摘要:

Journal of the Chemical Society,Faraday Transactions IISSN 0300-959J.C.S. FARADAY I AUTHOR INDEX VOL. 76 (1980) 1Abe, Yoshiyuki, 2531-41Abraham, Michael H., 869-84,Adams, Paul A., 21 14-23,1219-312 1 24-7Agarwal, Suraj P., 570-7,Akitt. J. W.. 2212-20.2259-842 187-93Albery, W. John, 1391-401Alesbury, Colin K., 244-55Alexander, David M., 118-25Allsopp, Stephen R., 162-73Amira, Mohamed F., 1773-8Amir-Ebrahimi, Valia, 1704-22Amodio, Christopher A.,Amouyal, Edmond, 2432-6Amu, Thomas C., 1433-41Anderson, Yvonne, 196-208Anichini, Anna, 2448-56Anpo, Masakazu, 1014-20Ashmawy, Fathy M., 2096-101Attwood, David, 570-7,2187-93Attwood, Philip A., 2310-21Azuma, Katuhiko, 588-96,2Backlund, Sune, 2035-42Bahadur, Lal, 1409-1 8Balaram, Padmanabhan,Baldwin, Michael A., 838-45Baldwin, Roy R., 825-37,Bamford, Clement H ., 107- 1 1,Baranski, Andrzej S., 1962-77Barber, Michael, 549-59Barnes, Geoffrey T., 1 18-25Barrer, Richard M., 180-95,Barri, Sami, 1038-51Bartocci, Carlo, 797-803Basahel, Sulaiman N., 107-1 1,Bassanelli, Roberto, 2003-10Bennett, Joan P., 1075-92,Bensasson, Rene V., 1800-10,Benziger, Jay B., 49-59Beyer, Hermann K., 332-44Bhattacharya, Ashok K., 126-34Bicknell, Roy T.M., 637-47Biehl, George E., 196-208Birdi, Kulbir S., 2035-42Blackburn, G. Michael, 9 1 5-22Blanch, Jan H., 1905-10Bolis, Vera, 1606-1 6Bolton, Anthony P., 84-91Bomchil, Guillermo, 201 1-16Bond, Geoffrey C., 889-9001723-34, 1735-561669-76PLATES1008-131075-92,2374-82,2396412112-17l03,8-Sl112-172396-4122432-6AUTHOR INDEX, 1980Bonnett, Raymond, 852-9Boodts, Julien F.C., 1689-93Boucher, Ernest A., 520-7,Boughy, Alain, 1547-6 1Bowker, Michael, 758-73Bradshaw, David I., 979-87Braga, Mauro M., 152-61Bridgewater, Alan J., 1811-20Brookes, Hugh C., 2296-309Brooks, Brian W., 1599-605Brouillard, Raymond, 583-7Brown, Norman M. D., 2335-46Buckland, Anthony D., 302-1 3Buelow, Martin, 597-61 5,2Bueno, Willie A., 1689-93Bullock, Anthony T., 648-53,Burch, Robert, 181 1-20,2285-9Bussiere, Paul, 1652-9Bystroem, Katarina, 1986-90Campbell, Kenneth C., 2322-34Candy, Jean Pierre, 616-29Canham, Paul A., 1857-67,lCanosa, Carlos E., 846-5 1Carless, Howard A. J., 1849-56Castellanos, Maria, 21 59-69Cebula, Deryck J., 3 14-2 1Chadwick, Alan V., 2194-205Chadwick, Andrew T., 1391-401Charalambides, A.A., 852-9Che, Michel, 1526-34Cichocki, Andrzej, 1380-7Clancy, Paulette, 174-9Clarke, E. Colin W., 191 1-16Clarke, John K. A., 345-56,Clayton, Paul R., 2362-73Clewley, John D., 196-208Clune, T. Gerard, 1 13 1-7Coles, Barry A., 1391-401Compton, Richard G., 1391401Conlin, Robert T., 322-3 1Cooper, Maureen, 192341,2Cordischi, Dante, 1147-57Cornet, Daniel, 95242Corti, Horacio, 21 79-86Costela, Angel, 30-42Cox, Alan, 162-73,797-803,Cox, Brian G., 1 13 1-7Crovetto, Rosa, 2179-86Czapkiewicz, Jan, 1663-8Czapkiewicz-Tutaj, Bozena,Dalsager, Soeren U., 2035-42Da Luz, h a M. P. R., 152-61Danil de Namor, Angela F.,14 19-32PLATES1296-300PLATE1640-51PLATES804-1 11663-8869-84Das, Rebati C., 2152-8Das, Suresh, 1779-89Dash, Upender N., 2152-8Datka, Jerzy, 70510,2437-47Davidson, Iain M.T., 1520-5Davidson, R. Stephen, 2587-603Davis, Burtron H., 92-100,Davis, Harold B., 1991-2002Dawkins, John V., 1263-74Defosse, Camille, 1677-88,Delannay, Francis, 988-97,21917-222052-64,1 PLATEPLATES, 1677-88,1766-72,2052-64,l PLATE, 2128-41,lPLATEDe Lisi, Rosario, 1660-2Delmon, Bernard, 929-38,988-97,2 PLATES, 1677-88,176672,2052-64,1 PLATE,212841,l PLATEDenny, Lisa R., 1868-74Derouane, Eric G., 1606-16De Roy, Gilbert, 1166-73,De Valera, Eamon, 560-9Devine, Clare, 1052-61De Violet, Philippe Fornier,Diekmann, Stephan, 446-7Doncaster, Alan M., 272-9Duke, Martin G., 1232-9Duncan, Robert H., 2212-20Dunn, Anthony G., 2362-73Duplatre, Gilles, 152-61Eastland, George W., 1868-74Ebeid, El-Zeiny M., 2170-8Eden, Joyce, 426-34Egawa, Chikashi, 280-90Ehrhardt, Klaus, 597-615,2Elef, D.D., 1388-90Engels, Siegfrid, 782-9Eriksen, Trygve E., 1402-8Evers, Edward L., 528-36Fairhurst, Shirley A., 1490-509Fawcett, W. Ronald, 1962-77Feakins, David, 560-9,637-47Fernandez-Prini , Roberto,Figuera, Juan M., 30-42Figueras, Francois, 1652-9Finger, Gerd, 597-61 5,2Fisicaro, Emilia, 2102-1 3Flanagan, Ted B., 196-208Flockhart, Brian D., 2026-34Flowers, Michael C., 2290-5Floyd, Robert B., 2335-46Forissier, Michel, 1652-9Fornasier, Roberto, 1301-10Fouilloux, Pierre, 61 6-292542-5 1578-82PLATES21 79-86PLATE2 J.C.S.FARADAY I AUTHOR INDEX VOL. 76 (1980)Frahm, Jens, 446-7Francis, Stephen R., 1455-65Fraser, David, 1585-98Freer, Robert, 1021-9, 1030-7Freiberg, Mira, 1825-37,French, Han T., 537-48Frennet, Alfred, 1704-22Frey, Henry M., 322-31,Friedt, Jean Marie, 1652-9Fromon, Michel, 1062-74Fukushi, Kohji, 291-301Funabiki, Masaki, 2237-50Furlong, D. Neil, 774-81Furlong, Donald N., 457-66,Furukawa, Kazuo, 1 185-95Gajardo, Patricio, 929-38,Garbowski, Edouard, 1942-52,Garrone, Edoardo, 2 102- 13Gascoyne, Peter R. C., 426-34Gault, Francois G., 1547-61,Gavin David L., 648-53Geiger, Alfons, 135-5 1Genet, Michel, 403-16,2Gentry, Stephen J., 2084-95Getoff, Nikola, 1576-84Ghiotti, Giovanna, 2102-13Gilbert, Robert G., 1323-43,Glew, David N., 191 1-16Goffredi, Mario, 1660-2Goncalves, Raquel M.C., 753-7Gonzalez-Elipe, Augustin R.,Goodwin, James W., 225-35Gramain, Jean Claude, 1 800- 10Grange, Paul, 929-38,988-97,2Grant, David J. W., 2417-31Gravelle, Pierre C., 512-19,Guarino, Angelo, 2003-10Gubbins, Keith E., 174-9,Guczi, Laszlo, 782-9Gunnarsson, Gudmundur,Haberlandt, Reinhold, 1569-75Hakala, Marja Riitta, 473-88Hales, Philip W., 2080-3Hall, Denver G., 386-93,Hansen, Finn Knut, 1240-62Hansford, Denise T., 24 17-3 1Harding, David A., 180-95Harriman, Anthony, 1978-85Harris, Kenneth R., 377-85Harrison, Philip G., 442-5, 1Hartland, Stanley, 457-66,Harvey, John M., 256-65Hawkett, Brian S., 1323-431838-481849-56467-72988-97,2 PLATES1 953-6 11704-22,1723-34,1735-56PLATES1344-551535-46PLATES2221-82496-5061287-9525 7 5-8 6PLATE467-72Healy, Thomas W., 1-8,9-18Hedge, Robyn M., 236-43Hemidy, Jean Francois, 952-62Hendrickx, Maria, 1166-73Hennebert, Paul, 952-62Herrmann, Jean Marie, 1138-46Hertz, H.Gerhard, 135-51Holbrook, Kenneth A., 1232-9Holt, Susan, 2362-73Honeyman, Malcolm R., 2290-5Houalla, Marwan, 1766-72,2128-41,l PLATEHoward, Christopher B.,1296-300Hughes, Barry D., 963-78Hurwitz, Henri D., 2558-74,1Ichikawa, Kazuhiko, 291-301Idris Ali, Khondoker M., 49-56Imanaka, Toshinobu, 998-1007Imelik, Boris, 1942-52,195361Indovina, Valeno, 1147-57Ingram, Malcolm D., 648-53Inui, Tomoyuki, 2237-50Iwasawa, Yasuhiro, 939-51Jackson, Susan E., 256-65Jacobs, Peter A., 3324,403-16,Jafelicci, Miguel, 674-82James, Robert O., 1-8Jaroniec, Mieczyslaw, 2486-95Jayson, Gerald G., 528-36Jenard, Andre, 2558-74, 1Jewur, Shantappa S., 746-52John, Christopher S., 1356-65,Johnson, G.R. Alastair, 1779-89Jones, Alan, 2084-95Jones, Malcolm N., 654-64Jones, Timothy G. J., 520-7,Joyner, Richard W., 357-61Kaeger, Joerg, 597-615,2Kaerger, Joerg, 717-37, 1562-8,Kane, Alan F., 1 6 6 5 1Kemball, Charles, 1366-79Kemeny, Gabor, 782-9Kemp, Terence J., 162-73,Kennedy, Lois V. F., 1356-65Khosla, Mohinder P., 2043-51King, David A., 758-73Kiss, Akos, 3 3 2 4Kittaka, Shigeharu, 728-45Klinowski, Jacek, 1038-5 1Koehler, Gottfried, 157684Koga, Osamu, 19-29Kondo, Yasuhiko, 812-24Koresh, Jacob, 2457-71, 1Kosugiyama, Otoya, 253 1-41Krumgalz, Boris S., 1275-86,Krzywicki, Andrzej, 131 1-22Kubokawa, Yutaka, 1014-20PLATE2 PLATESPLATE1366-791419-32PLATES1569-75797-803,804-11PLATE, 2472-85,2507-91887-904Kubota, Junichi, 588-96,2Ladd, Irwin R., 84-9 1Lally, Thomas P., 1857-67, 1Land, Edward J., 852-9Lansdowne, Stephen W.,Laub, Richard J., 362-7Lawrence, Kenneth G., 637-47Ledoux, Marc J., 1547-61Leeman, Hugo, 2519-30Lemaitre, Jacques, 1677-88Lenkait, Jan A., 1391-401Levy, Leon Y., 2558-74, 1Leyendekkers, Jean V., 1206-18Liew, Kong Yong, 2026-34Lilley, Terence H., 901-5,906-14Liszi, Janos, 1219-31Liukkonen, Simo, 2552-7Lobo, Lelio Q., 1769,2496-506Logan, S.R., 578-82Luckham, Paul F., 674-82Lycourghlotis, Alexis, 1677-88,Maccoll, Allan, 838-45Machado, Jose C., 152-61Machado, Jose R. S., 2496-506McNicol, Brian D., 2310-21Maitra, A. Kumar, 1849-56Malatesta, Francesco, 25 l(r18Malcolme-Lawes, David J.,Manley, Philip, 654-64Marcantonatos, Minas D.,Marcus, Yizhak, 2347-61Marczewski, Marek, 13 1 1-22Marshall, Roger M., 846-51Martin, Margarita, 30-42Mason, Nigel B., 2285-9Mathieu, Michel V., 1942-52,Matijevic, Egon, 1240-62Matsumoto, Yoshio, 11 16-21,Matsuura, Ikuya, 2 128-4 1, 1Matusek, Karoly, 782-9Meehan, Peter, 201 1-16Mendelovici, Efraim, 1442-54Metcalfe, Alan, 489-95, 630-6Meyerstein, Dan, 1825-37,Mihalyfi, Judit, 332-44Mink, Janos, 782-9Mitchell, Philip C.H., 181 1-20Miyajima, Hiroyuki, 2531-41Miyake, Michihiro, 1185-95Moerke, Wolfgang, 782-9Moffat, John B., 746-52Momota, Hiroko, 790-6,2Monk, Cecil B., 1773-8Mooney, James, 2322-34Moore, P. B., 1388-90Morikawa, Akira, 1 196-205PLATESPLATE1344-55PLATE9 15-222052-64,1 PLATE860-81093-1 151953-6 11 122-30PLATE1838-48PLATEJ.C.S. FARADAY I AUTHOR INDEX VOL. 76 (1980) 3Morikawa, Hideki, 1185-95Morimoto, Tetsuo, 728-45Morishige, Kunimitsu, 728-45Moriyasu, Tsutomu, 728-45Morsi, Salah E., 2170-8Morterra, Claudio, 2102-13Mortimer, Michael, 236-43Moses, Edwin, 906-14Mott, Christopher J. B.,Moyes, Richard B., 979-87,Mruzek, Margaret N., 838-45Mulac, William A., 183848Munuera, Guillermo, 1535-46Nagashima, Akira, 253 1-41Nakamura, Teiji, 939-51Nakata, Kazuo, 1 196205Napper, Donald H., 1323-43,Nelson, W. John, 2335-46Newton, J.Michael, 2417-31Nicholas, John E., 1669-76Nitta, Yuriko, 998-1007Noszticzius, Zoltan, 2552-7Oakenfull, David, 1875-86Occhiuzzi, Manlio, 1147-57O’Donohoe, Cormac, 345-56Ogasawara, Sadao, 939-51Ohno, Hideo, 1185-95Okada, Kiyoshi, 1185-95Okamoto, Yasuaki, 998-1007Okura, Ichiro, 2209-1 1Olivier, Daniele, 1526-34Olofsson, Gerd, 1287-95Omar, Musa M., 71 1-16Onishi, Takaharu, 19-29,280-90Ono, Yoshio, 43541Otsuka, Kiyoshi, 1196-205Packer, Kenneth J., 1455-65Panda, Kshama N., 2 152-8Parayre, Patrick, 1704-22,Pass, Geoffrey, 2080-3Passiniemi, Pentti, 2552-7Paterson, Russell, 1052-61Patrykiejew, Andrzej, 2486-95Paul, Roger L., 2296-309Pawelka, Zbigniew, 43-8Pease, Wayne R., 1510-19,2Pekenc, Erdogan, 225-35Perez, Juan M., 30-42Pethig, Ronald, 426-34Pethybridge, Alan D., 368-76Pfeifer, Harry, 717-37, 1569-75Phillips, Courtenay S.G.,Pichat, Pierre, 1138-46Pickering, Ian A., 2374-82Pink, Richard C., 2026-34Poncelet, George, 403-16,2Porta, Piero, 2448-56Portefaix, Jean Louis, 1652-9Posadas, Dionisio, 1633-9Possagno, Elvira, 2003-10Pottinger, Ruth, 1849-561991-20021585-981344-5511 16-21,1122-301723-34PLATES683-700PLATESPratt, Graham L., 1694-703Price, Colin, 1857-67, 1 PLATEPrimet, Michel, 1942-52,Prinsloo, Jeremia J., 512-19,Purnell, J. Howard, 362-7Pyke, David R., 1174-82,2Ramanamurti, Medepalli V.,Rand, Brian, 225-35Rao, C.N. Ramachandra,Rao, Ch. Pulla, 1008-13Rao, Kalya J., 1617-28Rasko, Janos, 2383-95Rastogi, Pushti P., 2251-8Rauscher, Monika, 717-37Rayment, Trevor, 201 1-16Redszus, Christel, 597-61 5,2Reed, W. John, 162-73,797-803Reid, Robert, 1174-82,2Rendall, Henry M., 2575-86Rendall, W. Alan, 1757-65Renouprez, Albert J., 616-29Reucroft, Philip J., 1917-22Richard, Marie, 1526-34Riekel, Christian, 158598Ring, Morey A., 1520-5Rives-Amau, Vicente, 394-402Robb, Ian D., 528-36Rochester, Colin H., 302-13,Rogers, David, 1694-703Rogne, Otto, 1905-10Ronfard-Haret, Jean Claude,Rooney, John J., 345-56Roscoe, John M., 1757-65Rosenholm, Jar1 B., 473-88Rossemyr, Leif I., 1905-10Rouquerol, Francoise, 7768 1Rouquerol, Jean, 774-8 1Roussy, Georges, 1547-61Rouxhet, Paul G., 147689Rundqvist, Stig, 196208Russell, Sayra N., 19 17-22Ruthven, Douglas M., 60-70,Sampson, Christopher, 1585-98Sanchez, Jean Pierre, 1652-9Sangster, David F., 134455Sanz, Jesus, 1535-46Schirmer, Wolfgang, 597-61 5,2Schmidt, Klaus H., 1838-48Scholes, George, 449-56Schoonheydt, Robert A.,Schulz, Ronald A., 869-84Scokart, Paul O., 1476-89Scott, Kevin F., 683-700,Segall, Robert L., 1510-19, 21 953-6 12221-8PLATES1409-181008-13PLATES804-1 1PLATES1158-65,146675,2142-512432-671-83PLATES25 19-302065-79PLATESSendoda, Yoko, 435-41Senna, Mamoru, 7 9 0 4 2Sermon, Paul A., 885-8,889-900Shahidi, Fereidoon, 101-6Shalvoy, Richard B., 19 17-22Shamir, Jacob, 2347-61Shankar, S.Ude, 489-95,630-6Sheppard, John G., 21 14-23Sheppard, Norman, 394-402Sherwood, John N., 1021-9,Shindo, Hitoshi, 280-90Shippey, T. Ann, 2251-8Short, Richard T., 2310-21Sikand, Arvind, 180-95Sinclair, Roy S., 417-25,852-9Sing, Kenneth S. W., 774-81Sjoeberg, Lars, 1402-8Smart, Roger St. C., 1510-19,2Smith, Richard, 442-5, 1 PLATESmith, Robert W., 225-35Sobczyk, Lucjan, 43-8Soffer, Abraham, 2457-71,lSoffer, Neomy, 2347-61Solymosi, Frigyes, 2383-95Soma, Mitsuyuki, 1122-30Soria, Javier, 1535-46Sostero, Silvana, 162-73,Staveley, Lionel A. K., 174-9,Stenius, Per, 473-88Steyaer, Herman, 209-19Stock, Colin J., 496502Stokes, Roin H., 537-48Struve, Peter, 597-61 5,2Stubbersfield, Rita B., 1857-67, 1Summers, Dennis M., 362-7Sundar, H. G.Keshava, 1617-28Sutcliffe, Leslie H., 1490-509Swallow, A. John, 528-36Symons, Martyn C. R., 244-55,Taba, Shahab Soltani, 368-76Tadros, Tharwat F., 66573,Tait, David, 41 7-25,852-9Takagi, Michihiko, 790452Takamatsu, Kenichi, 939-5 1Takegami, Yoshinobu, 2237-50Tamaru, Kenzi, 19-29,280-90,Taplin, John H., 2229-36Tasker, Ian R., 90614Taylor, Graham, 1263-74Teranishi, Shiichiro, 998-1007Theobald, Francois, 1652-9Thomas, Robert K., 236-43,Thomson, Samuel J., 1923-41,2Thuan, Nguyen Kim, 2209-1 1Thun, Harry P., 209-19PLATES1030-7PLATESPLATE, 2472-85,2507-9797-8032362-73,2496-506PLATESPLATE256-65,1868-74,2251-8674-82PLATES1116-21, 1122-30314-21,2011-16PLATE4 J.C.S.FARADAY I AUTHOR INDEX VOL. 76 (1980)Tilley, Richard J. D., 1174-82,2Tokura, Niichiro, 8 12-24Tonellato, Umberto, 1301-10Topham, Susan A., 302-13Traverso, Orazio, 162-73,Treiner, Claude, 1062-74Trenwith, Antony B., 266-71Truscott, T. George, 417-25,Turco Liveri, Vincenzo, 1660-2Turner, Peter S., 151&19,2Tyler, J. Kelvin, 1356-65Valle, Luis, 30-42Van Amstel, Jan A., 2310-21Van de Berg, Jan, 1606-16Vandickelen, Rita, 2542-5 1Van Ewyk, Robert L., 2194-205Vansant, Etienne F., 1166-73,Van Wouwe, Dirk, 2519-30Varadarajan, R., 2017-25Vedrine, Jacques C., 1606-16Verbeek, Frans, 209-19Verbeek, Ronald M. H., 209-19PLATES797-803,804-11852-9PLATES2542-5 1Verdonck, Jos J., 403-16,2Viana, Cesar A.N., 753-7Vickerman, John C., 549-59Villalba, Rafael, 1442-54Vincent, Brian, 66573,674-82Vink, Hans, 1790-800Volkmer, Peter, 1562-8Waghorne, W. Earle, 560-9,Waigh, Roger D., 2187-93Walker, Raymond W., 825-37,Walker, Robert W., 825-37Walmsley, D. George, 233546Walmsley, Elizabeth, 91 5-22Walsh, Peter T., 2084-95Walsh, Robin, 272-9Walter, Andreas, 717-37Ward, Anthony J. I., 1131-7Watkins, Paul E., 503-1 1Weeks, Thomas J., Jr., 84-91Wells, Cecil F., 2017-25Wells, Peter B., 979-87, 1585-98Wennerstroem, Haakan, 2287-95West, Anthony R., 2159-69PLATES1131-71075-92,237682,2396-412White, John W., 236-43,314-21White, Lee R., 963-78Whittle, Eric, 496-502, 503-1 1Widom, Benjamin, 2043-5 1Williams, John O., 2170-8Williamson, James G., 1356-65,Willsher, Charles J., 2587-603Wolstenholme, John, 549-59Wolthuizen, Jillis P., 1606-16Wood, Robert H., 901-5Woolf, Lawrence A., 377-85Wright, Christopher J., 1585-98Wright, John D., 2194-205Yariv, Shmuel, 1442-54Yates, David E., 1-8,9-18Yong, Geok Hua, 1 158-65,Yoshida, Takeshi, 8 12-24Young, Colin A., 665-73Yucel, Hayrettin, 60-70, 71-83Yuki, Kazumi, 812-24Yun, Cheboc, 1014-20Zacharov, Anatolei, 1287-95Zamboni, Roberto, 2510-18201 1-161366-791466-75,2142-5J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 5SUBJECT INDEX, 19805AABSORPTIONApplication of absolute rate theory to intracrystalline diffusion in zeolites, 1569-75Benzophenone triplet properties in acetonitrile and water.Reduction by lactams, 1800-10Surface energetics of the wetting of a hydrophobic powder, 2417-31Infrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedPhotochemistry of anhydrides. Part 4. Photolysis of perfluoren-butyric anhydride. Reaction ofReactions of methyl radicals with oxetan, 2-methyloxetan and 2,4-dimethyloxetan, 1232-9Benzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-1 0Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofambient gas, 2194-205Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Effect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide.Variabletemperature proton magnetic resonance study, I 13 1-7Infrared study of the adsorption of N,N-diethylacetamide and three N,Ndiethylaminoketones on silicaimmersed in carbon tetrachloride, 2142-51Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbontetrachloride, 302-1 3Secondary ion mass spectra of some simple organic molecules, 549-59Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylacetate, 1857-67, 1 PLATEAdsorption and decomposition of isopropyl alcohol over zinc oxide.Infrared and kinetic study, 19-29Secondary ion mass spectra of some simple organic molecules, 549-59Solvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Raman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394-402Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in amodified proportional counter, 19234,2 PLATESStudy of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofmolecular sieving, 2457-7 1, 1 PLATEPartial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of C I , ~aminocarboxylic acids, 101-6Solubility of synthetic calcium hydroxyapatites, 209-19Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbontetrachloride, 302-13Aqueous solutions containing amino acids and peptides.Part 11. Enthalpy of dilution of single andbinary solute solutions of N-acetyl-glycine amide, N-acetyl-L-alanine amide, N-acetyl-L-valineamide and N-acetyl-L-leucine amide at 298.15 K, 91 5-22Heterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedmetal oxides, 1240-62Enthalpies of proton dissociation of poly(acry1ic acid). Comparison between experiment and theory for apolyelectrolyte system, 1287-95Electromotive force studies of electrolytic dissociation.Part 13. Dissociation constants of somedicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8Interaction of boric acid and borates with carbohydrates and related substances, 199112002Kinetics of the oxidation of formic acid by aquacobalt(II1) ions in aqueous perchlorate media, 2017-25Densities of binary liquid mixtures near their consolute points, 2043-51Thermodynamics of dissociation of m-malic, maleic, and fumaric acids in water and water + dioxanepolystyrene sulfonic acid membranes, 2558-74, 1 PLATEperfluoropropyl radicals with cyclohexane, 494-502ABSTRACTION.ACCEPTORACETAMIDEACETATE IACETONEACETONITRILERadiation and electron spin resonance study, 244-551062-74ACETYLENEACI6 J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980)ACID(contd)mixtures, 21 52-8at 6-60", 2347-61polystyrene sulfonic acid membranes, 2558-74, 1 PLATEIonic dissociation of aqueous hydrobromic acid. Part 2. Estimate from proton magnetic resonance dataInfrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedThermochemistry of hydroxylammonium and hydrazonium zeolites, 3 3 2 4Spectroscopic study of anatase properties. Part 3. Surface acidity, 2102-1 3Structural properties of antimony and tin mixed oxide catalysts, 1652-9Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylACIDITYACROLEINACRYLATEacrylate/carbon tetrabromide and styrene/methyl acrylate/ I-butanethiol and some general considerati-ons, 112-17metal oxides, 1240-62ACRYLICHeterocoagulation. Part 5.Adsorption of a carboxylated polymer latex on monodispersed hydratedAdsorption and activation of ethene by zeoliteH-ZSM-5, 1606-16Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-Stability of parameter estimates made using three- and four-parameter extended Arrhenius and Van'tThermodynamic functions for the system ethanol + pxylene from vapor pressures, enthalpies of mixingMolybdenumsarbon catalysts for reforming reactions, 18 1 1-20Extraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylElectron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogenACTIVATIONpentyl chloride in water, 21 14-23Hoff equations, 2124-7and volume of mixing and their interpretation in terms of association, 537-48ACTIVITYADDNradical and of the orientation of hydrogen atom addition to isobutene, 846-51comDounds and olefins.1490-509ADDUCTADSORBEDSelf-diffusion of n-Daraffins in NaX zeolite. 7 17-37ADSORPTIONTitanium dioxide-electrolyte interface. Part 1. Gas adsorption and tritium exchange studies, 1-8Influence of dipole interactions on surface reactions, 49-59Use of the Gibbs equation to calculate adsorption into monolayer-covered surfaces, 118-25Reaction mechanism of ammonia decomposition on tungsten, 280-90Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonThermochemistry of hydroxylammonium and hydrazonium zeolites, 3 3 2 4Adsorption maxima from solutions of ionic surfactants. A thermodynamic analysis, 386-93Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andnickekopper catalysts containing preadsorbed carbon monoxide, 5 12-1 9Hydrogen adsorption on platinum catalysts.Quantitative determination of the various speciespopulation, 6 16-29Interaction of oxygen with evaporated silicon films. An infrared study, 630-6Adsorption of small, positive particles onto large, negative particles in the presence of polymer.Part 1.Adsorption isotherms, 665-73Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Adsorption equilibrium and kinetics as a function of temperature, 674-82Interaction of hydroxyl groups in NaHY zeolites with physically adsorbed alkanes, 705-1 0Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-81Interaction of water with some silicas, 885-8Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption anddecomposition of nitric oxide, 1 1 16-21Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltoxide-magnesium oxide, 1 147-57Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Sorption in partially hydrated NaA and CaA zeolites, 1 166-73Heterocoagulation. Part 5.Adsorption of a carboxylated polymer latex on monodispersed hydratedPulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilInfrared study of silica immersed in 2,2+trimethylpentane + toluene + propionitrile mixtures, 146675tetrachloride, 302-1 3metal oxides, 124&62silica, 1455-6J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 7ADSORPTION(contd)Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 147689Photoadsorption and photodesorption of oxygen on highly hydroxylated titania surfaces. Part 3. Role ofSolution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,Adsorption and activation of ethene by zeolite-H-ZSM-5, 1606-16Ionic specific adsorption at the metal-solution interface, 1633-9Mechanism of isomerization of hydrocarbons on metals.Part 9. Isomerization and dehydrocyclization ofMechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 1. Benzene adsorptionSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 2. Hydrogenation ofNeutron diffraction from benzene adsorbed on graphite, 201 1-16Electron transfer at alumina surfaces. Part 6. Redox properties of fluorided aluminas, 2026-34Effect of sodium on the cobalt-molybdenumly-alumina system.Part 2. Influence of sodium content andpreparation methods on the state of dispersion and nature of molybdenum supported on y-alumina,Spectroscopic study of anatase properties. Part 3. Surface acidity, 2102-1 3Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaElectron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofTransformations of but-l-ene molecules adsorbed in NaHY zeolites studied by infrared spectroscopy,Study of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofStudy of molecular sieve carbons. Part 2. Estimation of cross-sectional diameters of nonsphericalTheory of adsorption from multicomponent liquid mixtures on solid surfaces and its application to liquidMolecular sieving range of pore diameters of adsorbents, 2507-9Analysis of electrical double-layer measurements, 2575-86Zeolite RHO.Part 2. Cation exchange equilibriums and kinetics, 1038-51Nitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Aggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneCatalytic conversion of alcohols. Part 10. Influence of pretreatment on the selectivity of magnesium andDielectric and electrical properties of hydrated bovine serum albumin, 426-34Catalytic conversion of alcohols.Part 10. Influence of pretreatment on the selectivity of magnesium andAdsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Reactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withEffect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Catalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withInelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumStructural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedReactions of aliphatic free radicals with copper cations in squeous solution.Part 2. Reactions with cuprichydrogen peroxide in photodesorption of oxygen, 1535-461599-6052-carbon-13-labeled 2,34imethylpentane on a 10% platinum-alumina catalyst, 1704-22of 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34on supports, 1942-52adsorbed species, 1953-612052-64, 1 PLATEimmersed in carbon tetrachloride, 2142-51ambient gas, 2194-2052437-47molecular sieving, 2457-7 1, 1 PLATEmolecules, 2472-85adsorption chromatography, 2486-95AFFINITYcalculated electron afinities, 1402-8AGGREGATIONosmometry, 2035-42calcium oxides, 92-100AIRALBUMINALC, calcium oxides, 92-100Adsorption isotherms, 665-73Adsorption equilibrium and kinetics as a function of temperature, 674-82cuprous ions: a pulse radiolysis study, 183848the selectivity, 1917-22oxide, 2335-46on temperature and pressure dependence of rate constants, 753-7ions: a pulse radiolysis study, 1825-37ALCOHOLYSISALIP8 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)ALKCarbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toInfrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedSmall angle neutron scattering from dilute aqueous dispersions of clay, 314-21Studies in ion solvation in nonaqueous solvents and their aqueous mixtures.Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Ionic viscosity B coefficients in dimethyl sulfoxide at 25, 35 and 45"C, 63747Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withCarbon-13 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toThermal transformation of goethite into hematite in alkali halide disks, 1442-54Electroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Ionic liquid mixtures. A modified quasi-lattice theory, 2296-309Infrared investigation of ionic hydration in ion-exchange membranes. Part 1.Alkaline salts of graftedHomologation of n-alkanes on metal films. A novel aspect of metal-carbene chemistry, 345-56Interaction of hydroxyl groups in NaHY zeolites with physically adsorbed alkanes, 705-10Self-diffusion of n-paraffins in NaX zeolite, 7 17-37Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Application of absolute rate theory to intracrystalline diffusion in zeolites, 1569-75Reactions of alkanes and cycloalkanes on platinum-gold alloy films, 1640-5 1Free radical mechanism in olefin isomerization. Isomerization of (ZFbut-2-ene and (Z)-[ 1,2-Interaction between lysozyme and n-alkyl sulfates in aqueous solution, 654-64Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Diffusion in n-alkylbenzenes.Diffusion of 1,1,2,2-tetrabromoethane in a homologous series of n-Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-Ionic limiting partial molal volumes in various solvents, 1887-904Electroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Diffusion in n-alkylbenzenes. Diffusion of 1,1,2,2-tetrabromoethane in a homologous series of n-New Zealand allophanes: a structural study, 2542-51Surface composition of palladium-gold alloys, 1 388-90Enthalpy of hydrogen in palladium alloys at constant interstitial volume, 2285-9Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Cracking of (5-13C)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-9 1Extended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-61Superacidity of modified y-alumina.Structure of active site and catalytic activity, 131 1-22Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 147689Effect of sodium on the cobalt-molybdenum-y-alumina system. Part 1. Influence of sodium content onthe state of dispersion and on the nature of the cobalt supported on y-alumina, 1677-88Joint studies by x-ray photoelectron spectroscopy and analytical electron microscopy of the dispersion ofnickel oxide supported on silica and silica-aluminas, 1766-72Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites.Part 1. Benzene adsorptionon supports, 1942-52Electron transfer at alumina surfaces. Part 6. Redox properties of fluorided aluminas, 2026-34Effect of sodium on the cobalt-molybdenumly-alumina system. Part 2. Influence of sodium content andpreparation methods on the state of dispersion and nature of molybdenum supported on y-alumina,Surface composition and catalytic activity of chromia-alumina catalysts, 2096-101amides, 1008-13polystyrene sulfonic acid membranes, 2558-74, 1 PLATEALKALIsome alkali metal chlorides at 298.15 K, 906-14amides, 1008-13polystyrene sulfonic acid membranes, 2558-74, 1 PLATEALKANEALKENE2H~lethylene over siloxene, 435-41ALKYLAdsorption isotherms, 665-73alkylbenzenes, 1433-41dimethylacetamide + water mixtures at 35", 1409-18ALKYLAMMONIUMALKYLBENZENEalkylbenzenes, 1433-4 1ALLOPH ANEALLOYALLY LMOLY BDENUMEssential factors for catalysis and reaction mechanisms, 939-5 1ALUMINA2052-64,l PLATJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 9ALUMINA(contd)Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumoxide, 2335-46ALUMINATEDistribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminate(CoGa,Alz-x04) spinel solid solutions, 2448-56Heterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedmetal oxides, 1240-62Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-molybdenum trioxide-alumina catalyst, 1356-65H ydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-alumina and molybdenum disulfide catalysts, 1366-79Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumoxide, 2335-46Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide.Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Carbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toamides, 1008-13Excitation energy effects on the fluorescence quantum yield in solution.Deactivation pathways foraromatic amines, 1576-84Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumoxide, 2335-46Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of a,*aminocarboxylic acids, 101-6Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of a,*aminocarboxylic acids, 101-6Aqueous solutions containing amino acids and peptides. Part 1 1. Enthalpy of dilution of single andbinary solute solutions of N-acetyl-glycine amide, N-acetyl-L-alanine amide, N-acetyl-L-valineamide and N-acetyl-L-leucine amide at 298.15 K, 91 5-22Partial molar volumes of organic compounds in water.Part 7. Sodium and hydrochloride salts of a,*aminocarboxylic acids, 101-6Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of a,*aminocarboxylic acids, 10 1-6Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaimmersed in carbon tetrachloride, 2 142-5 1Reaction mechanism of ammonia decomposition on tungsten, 280-90Infrared spectra of ammonia adsorbed on evaporated germanium films, 489-95Quenching of the photoluminescence of porous Vycor glass by oxygen and ammonia, 1014-20Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofTitanium dioxide-electrolyte interface.Part 2. Surface charge (titration) studies, 9-1 8Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Relative scale of free energy of transfer of anions from water to 1,2-dichloroethane, 1663-8Ionic limiting partial molal volumes in various solvents, 1887-904Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inHeterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousSpectroscopic study of anatase properties. Part 3. Surface acidity, 2102-13Surface energetics of the wetting of a hydrophobic powder, 2417-31Photochemistry of anhydrides. Part 4. Photolysis of perfluore-n-butyric anhydride. Reaction ofPhotochemistry of anhydrides.Part 5. Photolysis of perfluorosuccinic anhydride, 503-1 1ALUMINUMAMIDEAMINEAMINIUMAMINOAMINOCARBOXYLATEAMINOCARBOXYLICAMINOKETONEAMMONIAambient gas, 2 194-205AMMONIUMdetermined by neutron diffraction, 23643AMPHIPHILICaqueous solution, 21 87-93suspension of titanium dioxide, 1 138-46ANATASEANGLEANHYDRIDEperfluoropropyl radicals with cyclohexane, 496-5010 J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980)ANILINEExcitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forDetermination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarFormation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltNew method of separation of the viscosity B-coefficient of the Jones-Dole equation into ionicTube electrode and electron spin resonance.First-order kinetics, 1391-40 1Relative scale of free energy of transfer of anions from water to lY2-dichloroethane, 1663-8Some reactions at a mercury(I1) sulfide photoanode, 2587-603Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Calorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-Structures of tin oxide-antimony oxide catalysts, 1174-82,2 PLATESStructural properties of antimony and tin mixed oxide catalysts, 1652-9aromatic amines, 1576-84phases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36oxidemagnesium oxide, 1 147-57contributions for nonaqueous electrolyte solutions, 1275-86ANIONANODEANTHRACENEI), 2003-10ene photodimer, 21 70-8ANTIMONYAPATITESolubility of synthetic calcium hydroxyapatites, 209-19APROTICSpectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Effect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Improved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Solubility of synthetic calcium hydroxyapatites, 209-19Precise conductimetric studies on aqueous solutions of 2:2 electrolytes.Part 2. Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Transport in aqueous solutions of Group IIB metal salts. Part 7.Measurement and prediction of isotopicdiffusion coefficients for iodide in solutions of cadmium iodide, 1052-61Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Photochemistry and exciplex of the uranyl ion in aqueous solution, 1093-1 15The Tammann-Tait-Gibson model. Application to the heat capacities of aqueous electrolyte solutions,Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-Electromotive force studies of electrolytic dissociation. Part 13. Dissociation constants of someProperties of the borate ion in dilute aqueous solutions, 2179-86Proton nuclear magnetic resonance studies of the hydrolysis of the tetraaquaberyllium dication, 2212-20Proton nuclear magnetic resonance studies of the hydrolysis of the tetraaquaberyllium dication, 221 2-20Effect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Effects of wet vibro-milling on the polymorphic conversion of aragonite into calcite, 790-6,2 PLATESStructure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,New Zealand allophanes: a structural study, 2542-5 1Analysis of electrical double-layer measurements, 2575-86Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-81Exo-lectron emission from platinum wires cooling in hydrocarbons and other gases as observed in aExcitation energy effects on the fluorescence quantum yield in solution.Deactivation pathways forMagnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Mechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationAQ1062-741206-18dimethylacetamide + water mixtures at 35", 1409-18dicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8AQUAAQUABERYLLIUMAQUATIONARAGONITEAREAdetermined by neutron diffraction, 236-43ARGONmodified proportional counter, 1923-41,2 PLATESaromatic amines, 1576-84AROMAROM ATIZATIONof 2-carbon- 1 3-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-3J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 11ASSOCNThermodynamic functions for the system ethanol + pxylene from vapor pressures, enthalpies of mixingand volume of mixing and their interpretation in terms of association, 537-48Investigation of the self-association of an amphiphilic drug in aqueous solution, 570-7Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withsome alkali metal chlorides at 298.15 K, 906-14Aqueous solutions containing amino acids and peptides. Part 1 1. Enthalpy of dilution of single andbinary solute solutions of N-acetyl-glycine amide, N-acetyl-L-alanine amide, N-acetyl-L-valineamide and N-acetyl-L-leucine amide at 298.15 K, 9 15-22Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inaqueous solution, 2187-93Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylradical and of the orientation.of hydrogen atom addition to isobutene, 846-51Tritium recoil ranges and their influence on the helium moderator anomaly, 860-8Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andState of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossThermodynamics of liquid mixtures of nitrous oxide and xenon, 2496506Solid-solid phase transitions in azoxy compounds, 1986-90Improved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Effect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide. VariableSpectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 1476-89Ferromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34Zeolite sorbents.Modification by impregnation with salts, 18&95Wall effects in measurement of surface tension using a vertical cylinder. Part 2. Experimental, 467-72Diffusion in organic liquids. Part 1. Appraisal of a gel sectioning technique and its application to self-Diffusion in organic liquids. Part 2. Isotope-mass effects in self-diffusion in benzene and cyclohexane,Nitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andDiffusion in n-alkylbenzenes. Diffusion of 1,1,2,2-tetrabromoethane in a homologous series of n-Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites.Part 1. Benzene adsorptionSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 2. Hydrogenation ofNeutron diffraction from benzene adsorbed on graphite, 201 1-16Study of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofBenzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Assignment of transient species observed on laser flash photolysis of pbenzoquinone and methylated pThermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 1 52-61Thermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 1 52-6 1ATOMAUGERdecomposition of nitric oxide, 11 16-21spectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30AZEOTROPEAZOXYBARIUM1062-74BARRIERtemperature proton magnetic resonance study, 1 13 1-7BASEBASICITYBEAMBENZENEdiffusion in benzene and cyclohexane, 1021-91030-7calculated electron affinities, 1402-8alkylbenzenes, 1433-41on supports, 1942-52adsorbed species, 1953-61molecular sieving, 2457-71, 1 PLATEBENZOPHENONEBENZOQUINONEBENZOYLBENZOYLHYDROXYLAMINEbenzoquinones in aqueous solution, 2432-12 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)BENZYLInelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumoxide, 2335-46BENZY LAMINEInelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumoxide.2335-46BERYLLIUMProton nuclear magnetic resonance studies of the hydrolysis of the tetraaquaberyllium dication, 221 2-20Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingDensities of binary liquid mixtures near their consolute points, 2043-51Carbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toamides, 1008-1 3State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30Catalytic conversion of alcohols.Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withthe selectivity, 1917-22Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylacetate, 1857-67, 1 PLATEKinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofiodine, 272-9Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaIonic viscosity B coefficients in dimethyl sulfoxide at 25, 35 and 45T, 637-47Interaction of boric acid and borates with carbohydrates and related substances, 1991-2002Properties of the borate ion in dilute aqueous solutions, 2179-86Interaction of boric acid and borates with carbohydrates and related substances, 1991-2002Dielectric and electrical properties of hydrated bovine serum albumin, 426-34Zeolite sorbents.Modification by impregnation with salts, 180-95Kinetic study of the reaction of lead metal with hydrogen bromide in the temperature range 448-548 K,Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47Structural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedon temperature and pressure dependence of rate constants, 753-7Nucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueoussuspension of titanium dioxide, 1138-46Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-dimethylacetamide + water mixtures at 35", 1409-18Ionic liquid mixtures.A modified quasi-lattice theory, 2296-309Thermodynamic study of disorder in lithium bromide monohydrate, 2362-73Electrolyte diffusion at very low concentrations in ionized water, 2552-7Kinetic study of the reaction of lead metal with hydrogen bromide in the temperature range 448-548 K,Diffusion in n-alkylbenzenes. Diffusion of 1,1,2,2-tetrabromoethane in a homologous series of n-Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylBIACETYLI), 2003-10BINARYupper consolute temperatures, 362-7BINDINGBLOCKBONDimmersed in carbon tetrachloride, 2 142-5 1BORATEBORICBOVINEBROMIDE442-5,1 PLATEBROMINATION442-5, 1 PLATEBROMOETHANEalkylbenzenes, 1433-41methacrylate/l-butanethiol, 107-1 1BROMOMETHANJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 13BROMOMETHANE(c0ntd)Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ l-butanethiol and some general considerati-ons, 112-17Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylacetate, 1857-67, 1 PLATEExo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in amodified proportional counter, 1923-41,2 PLATESDiffusion in 5A zeolite. Study of the effect of crystal size, 71-83Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylHomologation of n-alkanes on metal films.A novel aspect of metal-carbene chemistry, 34556Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Chlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryReactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylDehydration-dehydrogenation selectivity of butan-2-1 on cadmium phosphate catalysts, 746-52Structural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedReactions of aliphatic free radicals with copper cations in aqueous solution.Part 2. Reactions with cupricCatalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withSecondary ion mass spectra of some simple organic molecules, 549-59Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaFree radical mechanism in olefin isomerization. Isomerization of (Z)-but-2-ene and (Z>-[ 1,2-Isomerization of cis-but-2-ene enhanced by sulfur dioxide adsorbed over decationated-Y and NaYBut-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Reactions of n-butenes on nickel films, 1547-61Transformations of but- l-ene molecules adsorbed in NaHY zeolites studied by infrared spectroscopy,Secondary ion mass spectra of some simple organic molecules, 549-59Structural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedon temperature and pressure dependence of rate constants, 753-7Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylradical and of the orientation of hydrogen atom addition to isobutene, 846-51Temperature-dependent hyperfine coupling constants in electron spin resonance.Part 6. Planar andnonplanar nitroxide radicals, 1296-300Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-pentyl chloride in water, 21 14-23Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Nucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in theConductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-Photochemistry of anhydrides. Part 4. Photolysis of perfluoro-n-butyric anhydride. Reaction ofDehydration-dehydrogenation selectivity of butan-2-01 on cadmium phosphate catalysts, 746-52Transport in aqueous solutions of Group IIB metal salts. Part 7. Measurement and prediction of isotopicEffects of wet vibro-milling on the polymorphic conversion of aragonite into calcite, 7 9 0 4 2 PLATESBUTADIENEBUTANEmethacrylate/l-butanethiol, 107-1 1and tertiary alkyl chlorides, 838-45BUTANETHIOLmethacrylate/ 1-butanethiol, 107-1 1BUTANOLon temperature and pressure dependence of rate constants, 753-7ions: a pulse radiolysis study, 1825-37the selectivity, 1917-22BUTANONEimmersed in carbon tetrachloride, 2142-5 12Hzlethylene over siloxene, 43541zeolites, 1196-205BUTENE2437-47BUTYLBUTYLAMINEBUTYLAMMONIUMmixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24dimethylacetamide + water mixtures at 35", 1409-18perfluoropropyl radicals with cyclohexane, 496-502BUTYRICCADMIUMdiffusion coefficients for iodide in solutions of cadmium iodide, 1052-61CALCIT14 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)CALCIUMDiffusion in 5A zeolite. Studv of the effect of crystal size.71-83Catalytic conversion of alcohols. Part 10. Influeke of pretreatment on the selectivity of magnesium andImproved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Solubility of synthetic calcium hydroxyapatites, 209-19Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Investigation of the self-association of an amphiphilic drug in aqueous solution, 570-7The Tammann-Tait-Gibson model. Application to the heat capacities of aqueous electrolyte solutions,Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 161 7-28Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Evaluation of Debye-Hueckel limiting slopes for water between 0 and 150", 191 1-16Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-Stability of parameter estimates made using three- and four-parameter extended Arrhenius and Van'tThermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneThermodynamic study of disorder in lithium bromide monohydrate, 2362-73Capillary phenomena. Part 10.Behavior of grooved rods at fluid/fluid interfaces, 520-7Capillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofInteraction of boric acid and borates with carbohydrates and related substances, 1991-2002Diffusion in 5A zeolite.Study of the effect of crystal size, 71-83Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( 1 OO), 126-34Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andnickel-copper catalysts containing preadsorbed carbon monoxide, 5 12-1 9Chemisorption of carbon monoxide on tungsten( 110) and tungsten(320) adsorption, desorption and stateinterconversion, 758-73Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Carbon-13 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toamides, 1008-1 3Diffusion in organic liquids.Part 2. Isotope-mass effects in self-diffusion in benzene and cyclohexane,1030-7Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption anddecomposition of nitric oxide, 11 16-21Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltoxide-magnesium oxide, 1 147-57Sorption in partially hydrated NaA and CaA zeolites, 116673Spectroscopic study of anatase properties. Part 3. Surface acidity, 2102-1 3Dynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Platinum on carbon fiber paper catalysts for methanol electrooxidation. Part 1. Influence of activationInfrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideStudy of molecular sieve carbons.Part 1. Pore structure, gradual pore opening, and mechanism ofStudy of molecular sieve carbons. Part 2. Estimation of cross-sectional diameters of nonsphericalMolecular sieving range of pore diameters of adsorbents, 2507-9Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthaipies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of a,*aminocarboxylic acids, 10 1-6Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbontetrachloride, 302-1 3Reactions of aliphatic free radicals with copper cations in aqueous solution.Part 2. Reactions with cupricions: a pulse radiolysis study, 1825-37calcium oxides, 92-100CALCNCAMPHORSULFONATECAPACITY120&18pentyl chloride in water, 21 14-23Hoff equations, 2 124-7mixtures, 21 52-8CAPILLARITYinfinite extent meeting solids in a gravitational field, 1419-32CARBOHYDRATECARBON2237-50conditions on catalytic activity, 23 10-21over chromia/alumina and chromia/silica, 2383-95molecular sieving, 2457-7 1, 1 PLATEmolecules, 2472-85CARBONATECARBOXYLATJ.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 15CARBOXYLICInfrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonEnthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,Thermodynamic properties of polyelectrolyte solutions.Part 2. Influence of the polyelectrolyte chargeThermodynamic properties of polyelectrolyte solutions, Part 2. Influence of the polyelectrolyte chargeAdsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousIsomerization of cis-but-2-ene enhanced by sulfur dioxide adsorbed over decationated-Y and NaYFunctional micellar catalysis. Part 3. Quantitative analysis of the catalytic effects due to functionalHydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-But-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Photoadsorption and photodesorption of oxygen on highly hydroxylated titania surfaces.Part 3. Role ofReactions of n-butenes on nickel films, 1547-61Reactions of alkanes and cycloalkanes on platinum-gold alloy films, 1640-5 1Cracking of (5-13C)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-91Catalytic conversion of alcohols. Part 10. Influence of pretreatment on the selectivity of magnesium andHomologation of n-alkanes on metal films. A novel aspect of metal-carbene chemistry, 345-56Extended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-61Raman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394-402Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andField-emission microscopic study of catalytic decomposition of methanol on metal surfaces.Part 1.Hydrogen adsorption on platinum catalysts. Quantitative determination of the various speciesGas-chromatographic studies of hydrocarbon hydrogenolysis on a nickel-silica catalyst, 683-700Dehydration-dehydrogenation selectivity of butan-2-01 on cadmium phosphate catalysts, 746-52Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Studies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Gravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminacatalysts in their oxidic precursor forms, 929-38Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Essential factors for catalysis and reaction mechanisms, 939-5 1Genesis, nature and dispersion of active phase in sulfided cobalt-molybdenumly-alumina hydrodesulfur-ization catalysts.Investigation by analytical electron microscopy and x-ray photoelectron spectroscop-Surface state and catalytic activity and selectivity of nickel catalysts in hydrogenation reactions. Part 2.Surface characterization of Raney nickel and Urushibara nickel catalysts by x-ray photoelectronspectroscopy, 998-1007State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30Structures of tin oxide-antimony oxide catalysts, 1174-82,2 PLATESFunctional micellar catalysis.Part 3. Quantitative analysis of the catalytic effects due to functionalmicelles and comicelles, 1301-10Superacidity of modified y-alumina. Structure of active site and catalytic activity, 13 11-22Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-molybdenum trioxide-alumina catalyst, 1356-65Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-alumina and molybdenum disulfide catalysts, 136679But-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Hydrogen sorption by molybdenum sulfide catalysts, 1585-98Structural properties of antimony and tin mixed oxide catalysts, 1652-9Effect of sodium on the cobalt-molybdenum-y-alumina system.Part 1 + Influence of sodium content ontetrachloride, 302-1 32080-3CARBOXYMETHYLCARBOXY METHY LHYDROXY ETHY Ldensity, 1790-800density, 1790-800CARBOXYMETHYLHYDROXYETHYLCELLULOSECATALYSISsuspension of titanium dioxide, 1138-46zeolites, 1196-205micelles and comicelles, 1301-10alumina and molybdenum disulfide catalysts, 1366-79hydrogen peroxide in photodesorption of oxygen, 1535-46CATALYSTcalcium oxides, 92- 100nickel-copper catalysts containing preadsorbed carbon monoxide, 5 12- 19Tungsten, 588-96,2 PLATESpopulation, 6 16-29y, 988-97,2 PLATESthe state of dispersion and on the nature of the cobalt supported on y-alumina, 1677-816 J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980)CATALYST(contd)Mechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization of2-carbon-13-labeled 2,3dimethylpentane on a 10% platinum-alumina catalyst, 1704-22Mechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationof 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34Mechanisms of isomerization of hydrocarbons on metals. Part 1 1. Isomerization and dehydrocyclizationof carbon-1 3-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-56Joint studies by x-ray photoelectron spectroscopy and analytical electron microscopy of the dispersion ofnickel oxide supported on silica and silica-aluminas, 1766-72Molybdenum-carbon catalysts for reforming reactions, 18 1 1-20Catalytic conversion of alcohols.Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withthe selectivity, 19 17-22Electron transfer at alumina surfaces. Part 6. Redox properties of fluorided aluminas, 2026-34Extraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Kinetics of methanol oxidation over platinum wire catalysts, 2084-95Surface composition and catalytic activity of chromia-alumina catalysts, 2096-101Physico-chemical characterization of impregnated and ion-exchanged silica-supported nickel oxide,Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withVolumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickelDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Platinum on carbon fiber paper catalysts for methanol electrooxidation.Part 1. Influence of activationTracer studies of retained hydrogen and surface residues on nickel catalysts. Isotopic exchange andInfrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideDehydration-dehydrogenation selectivity of butan-2-1 on cadmium phosphate catalysts, 74652Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Studies of hydrogen spillover.Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Thermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Zeolite RHO. Part 2. Cation exchange equilibriums and kinetics, 1038-51Effect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide. VariableNew method of separation of the viscosity B-coefficient of the Jones-Dole equation into ionicTube electrode and electron spin resonance. First-order kinetics, 1391-401Proton nuclear magnetic resonance studies of the hydrolysis of the tetraaquaberyllium dication, 22 12-20Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateInfrared study of silica immersed in 2,2,&trimethylpentane + toluene + propionitrile mixtures, 1466-75Thermodynamic properties of polyelectrolyte solutions.Part 2. Influence of the polyelectrolyte chargeEnthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,Small angle neutron scattering from dilute aqueous dispersions of clay, 314-21Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withModerated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylModerated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylWall-less reactor studies.Part 4. Isobutane pyrolysis, 1694-703Titanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossLimiting single-ion molar volumes. Intrinsic volume as a function of the solvent parameters, 2259-842128-41, 1 PLATEhematoporphyrin catalyzed by hydrogenase, 2209- 1 1and nickel-copper catalysts, 222 1-82237-50conditions on catalytic activity, 2310-21reactivity toward ethylene, 2322-34over chromia/alumina and chromialsilica, 2383-95CATALYTICCATIONtemperature proton magnetic resonance study, 1 13 1-7contributions for nonaqueous electrolyte solutions, 1275-86(C0Ga,A12-~04) spinel solid solutions, 2448-56CELLCELLULOSEdensity, 1790-8002080-3CESIUMsome alkali metal chlorides at 298.15 K, 90614methacrylate/l-butanethiol, 107-1 1acrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17CHAINCHARGEspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-3J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 17CHARGEDCHEMILUMINESCENCECHEMISORBEDApparent molal volumes of some highly charged electrolytes in water, 25 10-1 8Cyanide radical emission in the reaction of active nitrogen with methanol, 1757-65Reaction mechanism of ammonia decomposition on tungsten, 280-90Tracer studies of retained hydrogen and surface residues on nickel catalysts.Isotopic exchange andAdsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbontetrachloride, 302-1 3Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phasein NaY zeolite, 403-16,2 PLATESInfrared spectra of ammonia adsorbed on evaporated germanium films, 489-95Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andnickel-copper catalysts containing preadsorbed carbon monoxide, 5 12-1 9Field-emission microscopic study of catalytic decomposition of methanol on metal surfaces.Part 1.Tungsten, 588-96,2 PLATESThermal desorption study of surface hydroxyls on zinc oxide, 728-45Chemisorption of carbon monoxide on tungsten( 1 10) and tungsten(320) adsorption, desorption and stateinterconversion, 758-73Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Spectroscopic study of anatase properties. Part 3.Surface acidity, 2102-1 3Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickelDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Improved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Enthalpy of mixing of liquid hydrogen chloride and liquid xenon. Comparison of experiment and theoryZeolite sorbents. Modification by impregnation with salts, 180-95Investigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsPrecise conductimetric studies on aqueous solutions of 2:2 electrolytes. Part 2.Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 63747Structural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedon temperature and pressure dependence of rate constants, 753-7Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withsome alkali metal chlorides at 298.15 K, 906-14Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousAggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneEnthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inIonic liquid mixtures.A modified quasi-lattice theory, 2296309Chlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryreactivity toward ethylene, 2322-34CHEMISORPTIONand nickekopper catalysts, 2221-82237-50oxide, 233546CHLORIDE174-9225-3 51062-74suspension of titanium dioxide, 113846osmometry, 2035422080-3pentyl chloride in water, 21 14-23aqueous solution, 2187-93CHLORINEand tertiary alkyl chlorides, 838418 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)CHLOROKinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofChlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryChlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryChlorine kinetic isotope effects.Application of the transition state model to thermolysis of secondaryKinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofRelative scale of free energy of transfer of anions from water to 1,2-dichloroethane, 1663-8Reactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricChlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryZeolite sorbents. Modification by impregnation with salts, 180-95Gas-chromatographic studies of hydrocarbon hydrogenolysis on a nickel-silica catalyst, 683-700Extraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Theory of adsorption from multicomponent liquid mixtures on solid surfaces and its application to liquidSurface composition and catalytic activity of chromia-alumina catalysts, 2096101Infrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideThermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 1 52-61Inorganic photophysics in solution.Part 4. Deactivation mechanisms of the *E, state of chromium(II1)Surface composition and catalytic activity of chromia-alumina catalysts, 2096-101Infrared study of silica immersed in 2,2,4-trimethylpentane + toluene + propionitrile mixtures, 1466-75Isomerization of cis-but-2-ene enhanced by sulfur dioxide adsorbed over decationated-Y and NaYSmall angle neutron scattering from dilute aqueous dispersions of clay, 314-21Enthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,Investigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsGravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminacatalysts in their oxidic precursor forms, 929-38Genesis, nature and dispersion of active phase in sulfided cobalt-molybdenumly-alumina hydrodesulfur-ization catalysts.Investigation by analytical electron microscopy and x-ray photoelectron spectroscop-Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltoxide-magnesium oxide, 1 147-57Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-molybdenum trioxide-alumina catalyst, 1356-65Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-alumina and molybdenum disulfide catalysts, 136679Effect of sodium on the cobalt-molybdenum-y-alumina system.Part 1. Influence of sodium content onthe state of dispersion and on the nature of the cobalt supported on y-alumina, 1677-88Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Kinetics of the oxidation of formic acid by aquacobalt(II1) ions in aqueous perchlorate media, 2017-25Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateiodine, 272-9and tertiary alkyl chlorides, 838-45CHLOROALKANEand tertiary alkyl chlorides, 83845and tertiary alkyl chlorides, 83845CHLORODISILANEiodine, 272-9CHLOROETHANECHLOROFORMCHLOROBUTANEions: a pulse radiolysis study, 1825-37and tertiary alkyl chlorides, 838-45CHLOROPROPANECHROMATECHROMATOGadsorption chromatography, 2486-95CHROMIAover chromia/alumina and chromia/silica, 238S95CHROMIUMcomplexes from lifetime studies, 162-73CIRCULATIONCISzeolites, 1196-205CLAYCMC2080-3COAGULATION225-35COBALTy, 988-97,2 PLATESI), 2003-1J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 19COBALT(contd)COLLOIDCOMICELLE(CoGaxA12-x0,) spinel solid solutions, 2448-56Implications of elastic deformation on the direct measurement of surface forces, 963-78Functional micellar catalysis.Part 3. Quantitative analysis of the catalytic effects due to functionalSolid-solid phase transitions in azoxy compounds, 1986-90Transport in aqueous solutions of Group IIB metal salts. Part 7. Measurement and prediction of isotopicSurface composition of palladium-gold alloys, 1 388-90Surface composition and catalytic activity of chromia-alumina catalysts, 2096-101Numerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Precise conductimetric studies on aqueous solutions of 2:2 electrolytes. Part 2. Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Dielectric and electrical properties of hydrated bovine serum albumin, 426-34Conductance studies in amide + water mixtures.Part 5. Tetraalkylammonium bromides in N,N-dimethylacetamide + water mixtures at 35", 1409-1 8Adsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Capillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofSurface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofInfinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingDensities of binary liquid mixtures near their consolute points, 2043-51Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylRaman spectra of indium mono-, di-, and triiodides.Correlation between structure and thermodynamicDielectric properties of pure liquid N-methylacetamide, 7 1 1-16Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-Electromotive force studies of electrolytic dissociation. Part 13. Dissociation constants of someInfrared study of the solvation of halide ions by water and N-methylacetamide, 2251-8Surface energetics of the wetting of a hydrophobic powder, 2417-3 1New method of separation of the viscosity B-coefficient of the Jones-Dole equation into ionicCatalytic conversion of alcohols. Part 16.Attempt to correlate the ESCA oxygen 1s binding energy withReactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withHeterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedSurface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofFormation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylmicelles and comicelles, 1301-10COMPDCOMPLEXATIONdiffusion coefficients for iodide in solutions of cadmium iodide, 1052-61COMPNCONCNCONDCONDENSATIONCONEinfinite extent meeting solids in a gravitational field, 1419-32polystyrene and poly(dimethy1 siloxane), 1263-74upper consolute temperatures, 362-7CONFORMATIONCONSOLUTECONSTmethacrylate/l-butanethiol, 107-1 1properties of fused InxIl-x mixtures, 291-3011062-74dimethylacetamide + water mixtures at 35", 1409-18dicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8CONTACTCONTRIBUTIONcontributions for nonaqueous electrolyte solutions, 1275-86the selectivity, 1917-22ions: a pulse radiolysis study, 1825-37cuprous ions: a pulse radiolysis study, 1838-48metal oxides, 1240-62polystyrene and poly(dimethy1 siloxane), 1263-74acetate, 1857-67, 1 PLATECONVERSIONCOORDINATIONCOPOLYME20 J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980)COPOLYMNModerated copolymerization. Part 4.Penultimate unit effect in chain transfer: system styrene/methylModerated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrenelmethylmethacrylate/l-butanethiol, 107-1 1acrylate/carbon tetrabromide and styrene/methyl acrylatell-butanethiol and some general considerati-ons, 112-17nickekopper catalysts containing preadsorbed carbon monoxide, 5 12-1 9COPPERVolumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andStudies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Reactions of aliphatic free radicals with copper cations in aqueous solution.Part 2. Reactions with cupricReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withVolumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickelImproved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aTemperature-dependent hyperfine coupling constants in electron spin resonance. Part 6. Planar andLuminescence of porphyrins and metalloporphyrins. Part 1. Zinc(II), nickel(II), and manganese(I1)Cracking of (5-W)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-9 1Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Diffusion in 4A zeolite.Study of the effect of crystal size, 6CL70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Calorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofAssignment of transient species observed on laser flash photolysis of pbenzoquinone and methylated pDetermination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Photolysis of copper(I1) oxalato complexes in aqueous solution.Identification and reactions of anMechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in aCyanide radical emission in the reaction of active nitrogen with methanol, 1757-65Calorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-Calorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-Apparent molal volumes of some highly charged electrolytes in water, 2510-18Apparent molal volumes of some highly charged electrolytes in water, 2510-1 8Solid-solid phase transitions in azoxy compounds, 1986-901062-74ions: a pulse radiolysis study, 1825-37cuprous ions: a pulse radiolysis study, 1838-48and nickel-copper catalysts, 2221-8CORRELATIONCOUNTERmodified proportional counter, 1923-41,2 PLATESnonplanar nitroxide radicals, 1296-300porphyrins, 1978-85COUPLINGCRACKINGCRYPTANDCRYPTATECRYSTALdetermined by neutron diffraction, 236-43ene photodimer, 2170-8ambient gas, 2194-205benzoquinones in aqueous solution, 2432-6CUMOQUINONECUPCUPRICintermediate, 1779-89radio-frequency pulse discharge, 1669-76CYANIDECYAN0ene photodimer, 217CL8ene photodimer, 2170-8CYANOANTHRACENECYANOCOBALTATECYANOFERRATECYCLIJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 21CYCLOALKANECYCLOBUTANECYCLOHEXADIENEReactions of alkanes and cycloalkanes on platinum-gold alloy films, 1640-5 1Thermal unimolecular decomposition of 1,1,2,2-tetrafluorocyclobutane, 322-3 1Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( 1 OO), 126-34Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 12634Photochemistry of anhydrides.Part 4. Photolysis of perfluor*n-butyric anhydride. Reaction ofperfluoropropyl radicals with cyclohexane, 496-502Diffusion in organic liquids. Part 1.Appraisal of a gel sectioning technique and its application to self-diffusion in benzene and cyclohexane, 1021-9Diffusion in organic liquids. Part 2. Isotope-mass effects in self-diffusion in benzene and cyclohexane,1030-7Molybdenum-carbon catalysts for reforming reactions, 181 1-20Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption andStudies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Molybdenum<arbon catalysts for reforming reactions, 18 1 1-20Excitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forEvaluation of Deby+Hueckel limiting slopes for water between 0 and 150", 191 1-16Inorganic photophysics in solution.Part 4. Deactivation mechanisms of the 2E, state of chromium(II1)Inorganic photophysics in solution. Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Benzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Chlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryand tertiary alkyl chlorides, 838-45Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34Thermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 1 52-6 1Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofiodine, 272-9Reaction mechanism of ammonia decomposition on tungsten, 280-90Thermal unimolecular decomposition of 1,1,2,2-tetrafluorocyclobutane, 322-3 1Thermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Field-emission microscopic study of catalytic decomposition of methanol on metal surfaces.Part 1.Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andBut-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Tube electrode and electron spin resonance. First-order kinetics, 1391-401Reactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricKinetics of the thermal gas-phase decomposition of 2,3-epoxy- 1, 1, 1-trifluoropropane, 2290-5Implications of elastic deformation on the direct measurement of surface forces, 963-78Catalytic conversion of alcohols.Part 10. Influence of pretreatment on the selectivity of magnesium andAnalysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Dehydration-dehydrogenation selectivity of butan-2-01 on cadmium phosphate catalysts, 746-52Catalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withMechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization ofMechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationCYCLOHEXANECYCLOHEXENEdecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34CYCLOPENTANEDEACTIVATIONaromatic amines, 1576-84DEBYEDECAYcomplexes from lifetime studies, 162-73ed uranyl ion in hydroxylic solvents, 804-1 1DECHLORINATIONDECOMPNTungsten, 588-96,2 PLATESdecomposition of nitric oxide, 11 16-21ions: a pulse radiolysis study, 1825-37DEFORMATIONDEHYDRATIONcalcium oxides, 92-100the selectivity, 19 17-222-carbon-13-labeled 2,3-dimethylpentane on a 10% platinum-alumina catalyst, 1704-22of 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34DEHYDROCYCLIZATIO22 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)DEHYDROCYCLIZATION(contd)DEHYDROGENATIONMechanisms of isomerization of hydrocarbons on metals.Part 1 1. Isomerization and dehydrocyclizationAdsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Catalytic conversion of alcohols. Part 10. Influence of pretreatment on the selectivity of magnesium andThermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Dehydration-dehydrogenation selectivity of butan-2-01 on cadmium phosphate catalysts, 746-52Studies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Surface composition and catalytic activity of chromia-alumina catalysts, 2096-101Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 161 7-28Densities of binary liquid mixtures near their consolute points, 2043-5 1Thermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( 1 OO), 126-34Reaction mechanism of ammonia decomposition on tungsten, 280-90Thermal desorption study of surface hydroxyls on zinc oxide, 728-45Chemisorption of carbon monoxide on tungsten( 1 10) and tungsten(320) adsorption, desorption and stateComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Solution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsInorganic photophysics in solution. Part 6.Isotope effects in the nonradiative deactivation of photoexcit-Inorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedDeviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andMolecular sieving range of pore diameters of adsorbents, 2507-9Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonElectromotive force studies of electrolytic dissociation. Part 13. Dissociation constants of someThermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneRelative scale of free energy of transfer of anions from water to 1,2-dichloroethane, 1663-8Dielectric and electrical properties of hydrated bovine serum albumin, 426-34Dielectric properties of pure liquid N-methylacetamide, 7 1 1-16Conductance studies in amide + water mixtures.Part 5. Tetraalkvlammonium bromides in N,N-of carbon-1 3-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-56calcium oxides, 92-100DENSITYdimethylacetamide + water mixtures at 35", 1409-18DEPROTONATIONDESORPTIONinterconversion, 758-73DETERGENTDEUTERIUM196-208ed uranyl ion in hydroxylic solvents, 804-1 1state absorption and emission spectra, kinetics and energetics, 797-803lithium titanate-sodium titanate, 2 159-69DIAGRAMDIAMDICARBOXYLATEtetrachloride, 302-13dicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8mixtures, 2 152-8DICARBOXYLICDICHLOROETHANEDIELECdimethylacetamide + water mixtures at 35", 1409-18DIETHYLHydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaInfrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaInfrared study of the adsorption of N,Ncliethylacetamide and three N,N-diethylaminoketones on silicaInfrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaalumina and molybdenum disulfide catalysts, 1366-79immersed in carbon tetrachloride, 2142-5 1immersed in carbon tetrachloride, 2 142-5 1immersed in carbon tetrachloride, 2142-51immersed in carbon tetrachloride, 2142-5 1DIETHYLAMINEDIETHYLAMINODIETHYLAMINOKETONJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 23DIFFRACTIONHydrogen sorption by molybdenum sulfide catalysts, 1585-98New Zealand allophanes: a structural study, 2542-5 1Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Pressure and temperature dependence of the self-diffusion coefficient of water and oxygen-1 8 water,Self-diffusion of n-paraffins in NaX zeolite, 717-37Diffusion in organic liquids.Part 1. Appraisal of a gel sectioning technique and its application to self-Diffusion in organic liquids. Part 2. Isotopemass effects in self-diffusion in benzene and cyclohexane,Zeolite RHO. Part 2. Cation exchange equilibriums and kinetics, 1038-51Transport in aqueous solutions of Group IIB metal salts. Part 7. Measurement and prediction of isotopicDiffusion in n-alkylbenzenes. Diffusion of 1,1,2,2-tetrabromoethane in a homologous series of n-Comparison of predicted and nuclear magnetic resonance zeolitic diffusion coefficients, 1 562-8Application of absolute rate theory to intracrystalline diffusion in zeolites, 1569-75Electrolyte diffusion at very low concentrations in ionized water, 2552-7Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Diffusion in 5A zeolite.Study of the effect of crystal size, 71-83Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Aqueous solutions containing amino acids and peptides. Part 1 1. Enthalpy of dilution of single andbinary solute solutions of N-acetyl-glycine amide, N-acetyl-L-alanine amide, N-acetyl-L-valineamide and N-acetyl-L-leucine amide at 298.15 K, 91 5-22Enthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,2080-3Study of molecular sieve carbons. Part 2. Estimation of cross-sectional diameters of nonsphericalmolecules, 2472-85Calorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-ene photodimer, 21 70-8Effect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide.Variabletemperature proton magnetic resonance study, 1131-7Mechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization of2-carbon-13-labeled 2,3-dimethylpentane on a 10% platinum-alumina catalyst, 1704-22Effect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide. Variabletemperature proton magnetic resonance study, 1 13 1-7Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-dimethylacetamide + water mixtures at 35", 1409-18Mechanism of isomerization of hydrocarbons on metals.Part 9. Isomerization and dehydrocyclization of2-carbon-13-labeled 2,34imethylpentane on a 10% platinum-alumina catalyst, 1704-22Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1 263-74Thermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Thermodynamics of dissociation of m-malic, maleic, and fumaric acids in water and water + dioxaneIsomerization of cis-but-2+~1e enhanced by sulfur dioxide adsorbed over decationated-Y and NaYSpectroscopic study of anatase properties. Part 3. Surface acidity, 2102-1 3Effect of solvents on dipole moment of merocyanine, 43-8Influence of dipole interactions on surface reactions, 49-59Dielectric properties of pure liquid N-methylacetamide, 7 1 1-16Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisDIFFUSION377-85diffusion in benzene and cyclohexane, 1021-91030-7diffusion coefficients for iodide in solutions of cadmium iodide, 1052-61alkylbenzenes, 1433-41DIFFUSIVITYDILNDIMENSIONDIMERDIMETHYLDIMETHYLACETAMIDEDIMETHYLPENTANEDIMETHYLSILOXANEDIMETHY LVINYkOYETANEDIOXANEmixtures, 21 52-8zeolites, 1 196-205DIOXIDEDIPOLEDISCHARG24 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)DISCHARGE(contd)DISILANEof aqueous solutions, 648-53iodine, 272-9Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofThermodynamic study of disorder in lithium bromide monohydrate, 2362-73DISORDERDISPERSEExtended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-61DISPERSIONSmall angle neutron scattering from dilute aqueous dispersions of clay, 314-21Redox behavior of transition metal ions in zeolites.Part 8. Characterization of a ruthenium metal phaseDielectric and electrical properties of hydrated bovine serum albumin, 426-34Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofFerromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-Effect of sodium on the cobalt-molybdenum-y-alumina system. Part 1. Influence of sodium content onJoint studies by x-ray photoelectron spectroscopy and analytical electron microscopy of the dispersion ofAnalysis of electrical double-layer measurements, 2575-86How much may the equilibrium be shifted in a chemical relaxation experiment?, 583-7Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofElectromotive force studies of electrolytic dissociation. Part 13.Dissociation constants of someThermodynamics of dissociation of m-malic, maleic, and fumaric acids in water and water + dioxaneEvidence for modification of nickel oxide by silica. Infrared, electron microscope, and dissolution rateDetermination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarConstraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Extraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminate(CoGaxA12-x04) spinel solid solutions, 2448-56Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Carbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toamides, 1008-1 3Effect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 63747Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonNumerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Aggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneosmometry, 2035-42Thermodynamic properties of polyelectrolyte solutions. Part 2. Influence of the polyelectrolyte chargedensity, 1790-800Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofambient gas, 2194-205Evidence for modification of nickel oxide by silica.Infrared, electron microscope, and dissolution ratein NaY zeolite, 403-16,2 PLATESpolystyrene and poly(dimethy1 siloxane), 1263-74exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34the state of dispersion and on the nature of the cobalt supported on y-alumina, 1677-88nickel oxide supported on silica and silica-aluminas, 1766-72DISPLACEMENTDISPROPORTIONATIONiodine, 272-9dicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8mixtures, 21 52-8studies, 1510-19,2 PLATESphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36DISSOCNDISSOLNDISTRIBUTIONDMFDMSODODECANOATEtetrachloride, 302-1 3DODECYLDONNANDONORDOPANJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 25DOPANT(contd)DOUBLEstudies, 1510-19,2 PLATESElectroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Analysis of electrical double-layer measurements, 2575-86Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Carbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toInfrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedImplications of elastic deformation on the direct measurement of surface forces, 963-78Precise conductimetric studies on aqueous solutions of 2:2 electrolytes.Part 2. Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Dielectric and electrical properties of hydrated bovine serum albumin, 426-34State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30Analysis of electrical doublelayer measurements, 2575-86Electroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Platinum on carbon fiber paper catalysts for methanol electrooxidation. Part 1. Influence of activationTube electrode and electron spin resonance. First-order kinetics, 1391-401Electromotive force studies of electrolytic dissociation. Part 13.Dissociation constants of someAnalysis of electrical double-layer measurements, 2575-86Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisSome reactions at a mercury(I1) sulfide photoanode, 2587-603Titanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Improved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Precise conductimetric studies on aqueous solutions of 2:2 electrolytes. Part 2. Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76The Tammann-Tait-Gibson model. Application to the heat capacities of aqueous electrolyte solutions,120618Apparent molal volumes of some highly charged electrolytes in water, 2510-18Electrolyte diffusion at very low concentrations in ionized water, 2552-7Redox behavior of transition metal ions in zeolites.Part 8. Characterization of a ruthenium metal phasein NaY zeolite, 403-16,2 PLATESDetermination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Chemisorption of carbon monoxide on tungsten( 1 10) and tungsten(320) adsorption, desorption and stateinterconversion, 758-73State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30Nitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andcalculated electron affinities, 1402-8Exmlectron emission from platinum wires cooling in hydrocarbons and other gases as observed in amodified proportional counter, 1923-41,2 PLATESEffect of solvents on dipole moment of merocyanine, 43-8Luminescence of porphyrins and metalloporphyrins.Part 1 . Zinc(II), nickel(II), and manganese(I1)Platinum on carbon fiber paper catalysts for methanol electrooxidation. Part 1. Influence of activationAdsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Electroreduction of alkali metal cations.Part 1. Effects of solution composition, 1962-77DROPLETEARTHamides, 1008-1 3polystyrene sulfonic acid membranes, 2558-74, 1 PLATEELASTICELECELECTROCHEMconditions on catalytic activity, 23 10-2 1ELECTRODEdicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8ELECTROKINETICELECTROLYSISof aqueous solutions, 648-53ELECTROLYTEELECTRONELECTRONICporphyrins, 1978-85conditions on catalytic activity, 2310-21Adsorption isotherms, 665-73ELECTROOXIDNELECTROPHORESISELECTRORED26 J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980)ELECT ROST RICTIONPartial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of c t , ~Limiting single-ion molar volumes.Intrinsic volume as a function of the solvent parameters, 2259-84Primary processes in the low-pressure pyrolysis of methylsilane, 1520-5Chemisorption of carbon monoxide on tungsten( 1 10) and tungsten(320) adsorption, desorption and stateSeeded emulsion polymerization of styrene, 1323-43Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Solution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Dissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-71Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofInorganic photophysics in solution.Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Triplet states of porphyrin esters, 852-9Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Calculations on ionic solvation. Part 4. Further calculations in solvation of gaseous univalent ions usingone-layer and two-layer continuum models, 1219-3 1Relative scale of free energy of transfer of anions from water to 1,2-dichloroethane, 1663-8Complex formation between iodine and triphenylstibine oxide, 1689-93Catalytic conversion of alcohols.Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withThermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneIonic liquid mixtures. A modified quasi-lattice theory, 2296-309Surface energetics of the wetting of a hydrophobic powder, 2417-31Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Enthalpy of mixing of liquid hydrogen chloride and liquid xenon. Comparison of experiment and theory174-9Solution of hydrogen in nonstoichiometric phosphorus-deficient 3:1 palladium-phosphorus compounds196-208Thermodynamics of micellization and solubilization in the system water + sodium n-octanoate + n-pentanol at 25°C. Part 1.Partial molar enthalpies, 473-88Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Evaluation of Debye-Hueckel limiting slopes for water between 0 and 150°, 191 1-16Thermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxanemixtures, 21 52-8Enthalpy of hydrogen in palladium alloys at constant interstitial volume, 22859Surface energetics of the wetting of a hydrophobic powder, 24 17-3 1Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496506Enthalpy of mixing of liquid hydrogen chloride and liquid xenon. Comparison of experiment and theory1749Solution of hydrogen in nonstoichiometric phosphorus-deficient 3:1 palladium-phosphorus compounds196-208Studies in ion solvation in nonaqueous solvents and their aqueous mixtures.Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withsome alkali metal chlorides at 298.15 K, 906-14Calculations on ionic solvation. Part 4. Further calculations in solvation of gaseous univalent ions usingone-layer and two-layer continuum models, 12 19-3 1Complex formation between iodine and triphenylstibine oxide, 1689-93Solid-solid phase transitions in azoxy compounds, 1986-90Thermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneProperties of the borate ion in dilute aqueous solutions, 2179-86Ionic liquid mixtures.A modified quasi-lattice theory, 2296309aminocarboxylic acids, 10 1-6ELIMINATIONEMISSIONinterconversion, 758-73EMULSION1599-605ENERGYiodine, 272-9ed uranyl ion in hydroxylic solvents, 804-1 1the selectivity, 1917-22mixtures, 21 52-8ENTHALPYENTROPYmixtures, 21 52-J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 27ENTROPY (contd)EPOXYTRIFLUOROPROPANEEQUILThermodynamic study of disorder in lithium bromide monohydrate, 2362-73Surface energetics of the wetting of a hydrophobic powder, 2417-31Kinetics of the thermal gas-phase decomposition of 2,3-epoxy-l, 1, 1-trifluoropropane, 2290-5How much may the equilibrium be shifted in a chemical relaxation experiment?, 583-7Zeolite RHO.Part 2. Cation exchange equilibriums and kinetics, 1038-51Thermodynamic properties of polyelectrolyte solutions. Part 2. Influence of the polyelectrolyte chargeReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withInteraction of boric acid and borates with carbohydrates and related substances, 1991-2002But-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Solvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisMagnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltTube electrode and electron spin resonance.First-order kinetics, 139 1-401Electron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogenEffect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Electron transfer at alumina surfaces. Part 6. Redox properties of fluorided aluminas, 2026-34Stability of parameter estimates made using three- and four-parameter extended Arrhenius and Van’tTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Triplet states of porphyrin esters, 852-9Functional micellar catalysis.Part 3. Quantitative analysis of the catalytic effects due to functionalDiffusion in 4A zeolite. Study of the effect of crystal size, 60-70Application of absolute rate theory to intracrystalline diffusion in zeolites, 1569-75Exodectron emission from platinum wires cooling in hydrocarbons and other gases as observed in aSurface composition and catalytic activity of chromia-alumina catalysts, 2096-101Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Wall effects in measurement of surface tension using a vertical cylinder. Part 2. Experimental, 467-72Thermodynamic functions for the system ethanol + p-xylene from vapor pressures, enthalpies of mixingInelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumSurface energetics of the wetting of a hydrophobic powder, 2417-3 1Free radical mechanism in olefin isomerization.Isomerization of (Z)-but-2-ene and (Z)+ ,2-Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Adsorption and activation of ethene by zeoliteH-ZSM-5, 1606-1 6Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingInfinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingInfinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingNucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in thedensity, 179&800cuprous ions: a pulse radiolysis study, 1838-48ERIONITEESRRadiation and electron spin resonance study, 244-55of aqueous solutions, 648-53oxide-magnesium oxide, 1 147-57compounds and olefins, 149&509ESTHoff equations, 2 124-7ESTERmicelles and comicelles, 1301-10ETHANEmodified proportional counter, 1923-41,2 PLATESETH ANETHIOLalumina and molybdenum disulfide catalysts, 1366-79ETHANOLand volume of mixing and their interpretation in terms of association, 537-48oxide, 2335-46ETHENE2H2lethylene over siloxene, 435-41alumina and molybdenum disulfide catalysts, 1366-79ETHERupper consolute temperatures, 362-7upper consolute temperatures, 362-7upper consolute temperatures, 362-7ETHOXYETHANEETHY28 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)ETHYL(contd)mixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-alumina and molybdenum disulfide catalysts, 1366-79Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylacetate, 1857-67, 1 PLATEReactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Excitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forConductance studies in amide + water mixtures.Part 5. Tetraalkylammonium bromides in N,N-Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aTracer studies of retained hydrogen and surface residues on nickel catalysts. Isotopic exchange andReactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Titanium dioxide-electrolyte interface. Part 1. Gas adsorption and tritium exchange studies, 1-8Small angle neutron scattering from dilute aqueous dispersions of clay, 314-21Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Zeolite RHO. Part 2.Cation exchange equilibriums and kinetics, 1038-51Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Reactions of n-butenes on nickel films, 1547-61Physico-chemical characterization of impregnated and ion-exchanged silica-supported nickel oxide,Tracer studies of retained hydrogen and surface residues on nickel catalysts. Isotopic exchange andInfrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedPhotochemistry and exciplex of the uranyl ion in aqueous solution, 1093-1 15Inorganic photophysics in solution. Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aSolution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsThermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Infrared investigation of ionic hydration in ion-exchange membranes.Part 1. Alkaline salts of graftedMechanism of the photochemical reaction between ferrocene and iodine, 578-82Mechanism of the photochemical reaction between ferrocene and iodine, 578-82ETHY LAMINEaromatic amines, 1576-84dimethylacetamide + water mixtures at 35", 1409-18Adsorption isotherms, 665-73modified proportional counter, 1923-41,2 PLATESreactivity toward ethylene, 2322-34ETHYLAMMONIUMETHYLENEETHYLPEROXYEXCHANGEmolybdenum trioxide-alumina catalyst, 1356-65alumina and molybdenum disulfide catalysts, 1366-79212841,l PLATEreactivity toward ethylene, 2322-34polystyrene sulfonic acid membranes, 2558-74, 1 PLATEEXCIPLEXEXCITEDed uranyl ion in hydroxylic solvents, 804-1 1modified proportional counter, 1923-41,2 PLATES196-208EXOEMISSIONEXPANSIONFEPpolystyrene sulfonic acid membranes, 2558-74, 1 PLATEFERRICENIUMFERROCENEFERROCENOPH ANEMechanism of the photochemical reaction between ferrocene and iodine, 578-82FERROMAGNETICFerromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-Platinum on carbon fiber paper catalysts for methanol electrooxidation.Part 1. Influence of activationStudy of molecular sieve carbons. Part 1.Pore structure, gradual pore opening, and mechanism ofHomologation of n-alkanes on metal films. A novel aspect of metal-carbene chemistry, 345-56exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34conditions on catalytic activity, 23 10-21molecular sieving, 2457-71, 1 PLATEFIBERFILJ.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 29FILM(contd)FLASHInteraction of oxygen with evaporated silicon films. An infrared study, 630-6Assignment of transient species observed on laser flash photolysis of p-benzoquinone and methylated pInvestigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsExtraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79benzoquinones in aqueous solution, 2432-6FLOW225-35FLUIDCapillary phenomena. Part 1 1.Approximate treatment of the shape and properties of fluid interfaces ofinfinite extent meeting solids in a gravitational field, 1419-32FLUORESCENCEExcitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forLuminescence of porphyrins and metalloporphyrins. Part 1 . Zinc(II), nickel(II), and manganese(I1)Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Study of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofElectron transfer at alumina surfaces. Part 6. Redox properties of fluorided aluminas, 2026-34Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 147689Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Thermal unimolecular decomposition of 1,1,2,2-tetrafluorocyclobutane, 322-3 1Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofPhotochemistry of anhydrides.Part 4. Photolysis of perfluoro-n-butyric anhydride. Reaction ofThermal unimolecular decomposition of 1,1,2,2-tetrafluorocyclobutane, 322-3 1Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Photochemistry of anhydrides.Part 4. Photolysis of perfluoro-n-butyric anhydride. Reaction ofPhotochemistry of anhydrides. Part 5. Photolysis of perfluorosuccinic anhydride, 503-1 1Raman spectra of indium mono-, di-, and triiodides. Correlation between structure and thermodynamicImplications of elastic deformation on the direct measurement of surface forces, 963-78Field+mission microscopic study of catalytic decomposition of methanol on metal surfaces. Part 1.Tungsten, 588-96,2 PLATESFreezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingupper consolute temperatures, 362-7Field-emission microscopic study of catalytic decomposition of methanol on metal surfaces.Part 1.Tungsten, 588-96,2 PLATESPhotolysis of copper(I1) oxalato complexes in aqueous solution. Identification and reactions of anintermediate, 1779-89Dissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 26671Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37aromatic amines, 1576-84porphyrins, 1978-85I), 2003-10FLUORIDEmolecular sieving, 2457-71, 1 PLATEFLUORIDEDFLUORINATIONFLUOROdetermined by neutron diffraction, 236-43FLUOROBORANEambient gas, 2194-205perfluoropropyl radicals with cyclohexane, 496502FLUOROBUTYRICFLUOROCYCLOBUTANEFLUOROMETHANEFLUOROOCTANOATEdetermined by neutron diffraction, 236-43perfluoropropyl radicals with cyclohexane, 496-502FLUOROPROPY LFLUOROSUCCINICFORCEproperties of fused InxIl-x mixtures, 291-301FORMALDEHYDEFORMAMIDEFORMATEFORMATIO30 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)FORMATION(contd)FORMICFREEComplex formation between iodine and triphenylstibine oxide, 1689-93Infrared study of the solvation of halide ions by water and N-methylacetamide, 2251-8Kinetics of the oxidation of formic acid by aquacobalt(II1) ions in aqueous perchlorate media, 2017-25Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Calculations on ionic solvation.Part 4. Further calculations in solvation of gaseous univalent ions usingone-layer and two-layer continuum models, 12 19-3 1Relative scale of free energy of transfer of anions from water to 1 ,2-dichloroethane7 1663-8Complex formation between iodine and triphenylstibine oxide, 1689-93Thermodynamics of dissociation of m-malic, maleic, and fumaric acids in water and water + dioxaneIonic liquid mixtures. A modified quasi-lattice theory, 2296-309Surface energetics of the wetting of a hydrophobic powder, 241 7-3 1Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496506Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide.Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Reactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricions: a pulse radiolysis study, 1825-37Thermodynamics of dissociation of rx-malic, maleic, and fumaric acids in water and water + dioxanemixtures, 21 52-8Field+mission microscopic study of catalytic decomposition of methanol on metal surfaces. Part 1.Tungsten, 588-96,2 PLATESFunctional micellar catalysis. Part 3. Quantitative analysis of the catalytic effects due to functionalmicelles and comicelles, 1301-10Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingupper consolute temperatures, 362-7Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminate(CoGa,A12-x04) spinel solid solutions, 2448-56Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Diffusion in organic liquids.Part 1. Appraisal of a gel sectioning technique and its application to self-Infrared spectra of ammonia adsorbed on evaporated germanium films, 489-95Use of the Gibbs equation to calculate adsorption into monolayerxovered surfaces, 1 18-25Quenching of the photoluminescence of porous Vycor glass by oxygen and ammonia, 1014-20Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 161 7-28Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisInteraction of boric acid and borates with carbohydrates and related substances, 199 1-2002Aqueous solutions containing amino acids and peptides.Part 10. Enthalpy of interaction of glycine withAnalysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonThermal transformation of goethite into hematite in alkali halide disks, 1442-54Studies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Surface composition of palladium-gold alloys, 1 388-90mixtures, 2 152-8FREEZINGFUMARATEFUM ARICFUNCTIONFUNCTIONALFURANGALLATEGAMMAGELdiffusion in benzene and cyclohexane, 1021-9GERMANIUMGIBBSGLASSGLOWof aqueous solutions, 648-53GLUCOSEGLYCINEsome alkali metal chlorides at 298.15 K, 906-14GLYCOLGOETHITEtetrachloride, 302-1 3GOLJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 31GOLD(contd)GRAPHITEGRISEOFULVINGROOVEDGROUPReactions of alkanes and cycloalkanes on platinum-gold alloy films, 1640-5 1Neutron diffraction from benzene adsorbed on graphite, 201 1-16Surface energetics of the wetting of a hydrophobic powder, 2417-31Capillary phenomena. Part 10. Behavior of grooved rods at fluidlfluid interfaces, 520-7Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer.Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-lguanidine in acetonitrile and toluene, 1905-10Ionic viscosity B coefficients in dimethyl sulfoxide at 25, 35 and 45"C, 637-47Structural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedHeterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousThermal transformation of goethite into hematite in alkali halide disks, 1442-54Infrared study of the solvation of halide ions by water and N-methylacetamide, 2251-8Ionic liquid mixtures.A modified quasi-lattice theory, 2296-309Nitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andGUANIDINEHALIDEon temperature and pressure dependence of rate constants, 753-7suspension of titanium dioxide, 1138-46HAMcalculated electron affinities. 1402-8HARDNESSGlass formation in the ternarv sulfate svstem. Dotassium sulfatesodium sulfate-zinc sulfate, 161 7-28 r , A HEATKinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofiodine, 272-9Thermodynamics of micellization and solubilization in the system water + sodium n-octanoate + n-pentanol at 25°C. Part 1. Partial molar enthalpies, 473-88Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andnickel-copper catalysts containing preadsorbed carbon monoxide, 5 12-19Thermodynamic functions for the system ethanol + pxylene from vapor pressures, enthalpies of mixingand volume of mixing and their interpretation in terms of association, 537-48Studies in ion solvation in nonaqueous solvents and their aqueous mixtures.Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Sorption kinetics of n-hexane on MgA zeolites of different crystal sizes. Study of the rate-limitingtransport mechanism, 597-61 5,2 PLATESInteraction between lysozyme and n-alkyl sulfates in aqueous solution, 654-64Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-81Nucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withsome alkali metal chlorides at 298.15 K, 906-14Aqueous solutions containing amino acids and peptides. Part 1 1. Enthalpy of dilution of single andbinary solute solutions of N-acetyl-glycine amide, N-acetyl-L-alanine amide, N-acetyl-L-valineamide and N-acetyl-L-leucine amide at 298.15 K, 91 5-22Sorption in partially hydrated NaA and CaA zeolites, 1166-73The Tammann-Tait-Gibson model.Application to the heat capacities of aqueous electrolyte solutions,1206-18Enthalpies of proton dissociation of poly(acry1ic acid). Comparison between experiment and theory for apolyelectrolyte system, 1287-95Primary processes in the low-pressure pyrolysis of methylsilane, 1 520-5Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 1617-28Calorimetric determination of solution enthalpies of liquids with a small mutual solubility at 298.15 K,Complex formation between iodine and triphenylstibine oxide, 1689-93Evaluation of DebyeHueckel limiting slopes for water between 0 and 150°, 191 1-16Solid-solid phase transitions in azoxy compounds, 198690Enthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-1660-22080-3pentyl chloride in water, 21 14-232 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)HEAT(contd)Stability of parameter estimates made using three- and four-parameter extended Arrhenius and Van'tThermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneVolumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickelIonic liquid mixtures. A modified quasi-lattice theory, 2296-309Thermodynamic study of disorder in lithium bromide monohydrate, 2362-73Tritium recoil ranges and their influence on the helium moderator anomaly, 860-8Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonHeterocoagulation. Part 5.Adsorption of a carboxylated polymer latex on monodispersed hydratedThermal transformation of goethite into hematite in alkali halide disks, 1442-54Hoff equations, 2124-7mixtures, 21 52-8and nickel-copper catalysts, 2221-8HELIUMHEMATITEtetrachloride, 302-13metal oxides, 1240-62HEMATOPORPHYRINKinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withhematoporphyrin catalyzed by hydrogenase, 2209-1 1HEPTANEMolybdenum-carbon catalysts for reforming reactions, 18 1 1-20Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andExtraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofDissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-7 1Pulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilPulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilZeolite sorbents. Modification by impregnation with salts, 180-95Sorption kinetics of n-hexane on MgA zeolites of different crystal sizes.Study of the rate-limitingMechanism of isomerization of hydrocarbons on metals.Part 10. Isomerization and dehydrocyclizationMechanisms of isomerization of hyarocarbons on metals. Part 1 1. Isomerization and dehydrocyclizationMolybdenum-carbon catalysts for reforming reactions, 18 1 1-20Apparent molal volumes of some highly charged electrolytes in water, 2510-18Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylModerated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylHETEROGENEITYnickel-copper catalysts containing preadsorbed carbon monoxide, 5 12-1 9HETEROGENEOUSHEXACHLORODISILANEiodine, 272-9HEXADIENEHEXAMETHYLsilica, 1455-65silica, 1455-65HEXAMETHYLDISILOXANEHEXANEtransport mechanism, 597-6 15,2 PLATESof 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34of carbon-1 3-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-56HIGHLYHINDRANCEmethacrylate/l-butanethiol, 107-1 1acrylate/carbon tetrabromide ana styrene/methyl acrylate/l-butanethiol and some general considerati-ons, 112-17HOMOLOGATIONHOTHUECKELHYDRATEHYDRATEDHomologation of n-alkanes on metal films.A novel aspect of metal-carbene chemistry, 345-56Tritium recoil ranges and their influence on the helium moderator anomaly, 860-8Evaluation of Debye-Hueckel limiting slopes for water between 0 and 150", 191 1-16Thermodynamic study of disorder in lithium bromide monohydrate, 2362-73Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarDielectric and electrical properties of hydrated bovine serum albumin, 426-34Sorption in partially hydrated NaA and CaA zeolites, 1166-73phases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36HYDRATIOJ.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 33HYDRATION(contd)Properties of the borate ion in dilute aqueous solutions, 2179-86Infrared study of the solvation of halide ions by water and N-methylacetamide, 2251-8Infrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedThermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Ionic dissociation of aqueous hydrobromic acid.Part 2. Estimate from proton magnetic resonance dataUltraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption andZeolite sorbents. Modification by impregnation with salts, 180-95Gas-chromatographic studies of hydrocarbon hydrogenolysis on a nickel-silica catalyst, 683-700Molybdenum-carbon catalysts for reforming reactions, 18 1 1-20Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aSurface energetics of the wetting of a hydrophobic powder, 2417-3 1Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of c t , ~aminocarboxylic acids, 101-6Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inaqueous solution, 2 187-93HYDRODESULFURIZATIONGravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminacatalysts in their oxidic precursor forms, 929-38Genesis, nature and dispersion of active phase in sulfided cobalt-molybdenumly-alumina hydrodesulfur-ization catalysts. Investigation by analytical electron microscopy and x-ray photoelectron spectroscop-Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-alumina and molybdenum disulfide catalysts, 1366-79Catalytic conversion of alcohols.Part 10. Influence of pretreatment on the selectivity of magnesium andcalcium oxides, 92-1 00Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34Enthalpy of mixing of liquid hydrogen chloride and liquid xenon.Comparison of experiment and theory174-9Solution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compounds196-208Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phasein NaY zeolite, 403-16,2 PLATESKinetic study of the reaction of lead metal with hydrogen bromide in the temperature range 448-548 K,Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andnickel-copper catalysts containing preadsorbed carbon monoxide, 5 12-1 9Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Hydrogen adsorption on platinum catalysts. Quantitative determination of the various speciespopulation, 6 16-29Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisof aqueous solutions, 648-53Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylradical and of the orientation of hydrogen atom addition to isobutene, 846-51Studies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Gravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminacatalysts in their oxidic precursor forms, 929-38Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480"C, 1075-92Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Reactions of methyl radicals with oxetan, 2-methyloxetan and 2,44imethyloxetan, 1232-9Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Ferromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-Photoadsorption and photodesorption of oxygen on highly hydroxylated titania surfaces.Part 3. Role ofpolystyrene sulfonic acid membranes, 2558-74, 1 PLATEHYDRAZINIUMHYDROBROMICat 6-60", 2347-6 1decomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34HYDROCARBONmodified proportional counter, 192W1,2 PLATESHYDROCHLORIDEy, 988-97,2 PLATESHYDROGEN442-5, 1 PLATEmolybdenum trioxide-alumina catalyst, 1 3 5 6 5alumina and molybdenum disulfide catalysts, 1366-79exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34hydrogen peroxide in photodesorption of oxygen, 1535-434 J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980)HYDROGEN(contd)Hydrogen sorption by molybdenum sulfide catalysts, 1585-98Benzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aInfrared study of the adsorption of N,N&ethylacetamide and three N,N-diethylaminoketones on silicaVolumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickelDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Enthalpy of hydrogen in palladium alloys at constant interstitial volume, 2285-9Tracer studies of retained hydrogen and surface residues on nickel catalysts.Isotopic exchange andReactions of ethyl radicals with oxygen over the temperature range 400-540", 237482Study of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofMolecular sieving range of pore diameters of adsorbents, 2507-9Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withAdsorption and decomposition of isopropyl alcohol over zinc oxide.Infrared and kinetic study, 19-29Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andnickel-copper catalysts containing preadsorbed carbon monoxide, 5 12-19Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Studies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxidemolybdenum trioxide-Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites.Part 2. Hydrogenation ofDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Tracer studies of retained hydrogen and surface residues on nickel catalysts. Isotopic exchange andThermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Gas-chromatographic studies of hydrocarbon hydrogenolysis on a nickel-silica catalyst, 683-700Mechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization of2-carbon-13-labeled 2,34imethylpentane on a 10% platinum-alumina catalyst, 1704-22Mechanisms of isomerization of hydrocarbons on metals. Part 1 1. Isomerization and dehydrocyclizationof carbon-13-labeled 3-methylhexanes on platinum-alumina catalysts, 173 5-56Analysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Functional micellar catalysis.Part 3. Quantitative analysis of the catalytic effects due to functionalEffect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-Proton nuclear magnetic resonance studies of the hydrolysis of the tetraaquaberyllium dication, 2212-20Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Surface energetics of the wetting of a hydrophobic powder, 2417-31Heterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedmodified proportional counter, 1923-41,2 PLATESimmersed in carbon tetrachloride, 2142-5 1and nickel-copper catalysts, 2221-82237-50reactivity toward ethylene, 2322-34molecular sieving, 2457-71, 1 PLATEHYDROGENASEhematoporphyrin catalyzed by hydrogenase, 2209- 1 1HYDROGENATIONalumina and molybdenum disulfide catalysts, 1366-79adsorbed species, 1953-612237-50reactivity toward ethylene, 2322-34HYDROGENOLY SISHYDROHYDROXYURACILHYDROLYSISmicelles and comicelles, 1301-10pentyl chloride in water, 21 14-23HYDRONAPHTHALENEHYDROPHOBICHYDROXIDEmetal oxides, 1240-62HYDROXYSolubility of synthetic calcium hydroxyapatites, 209-19Solubility of synthetic calcium hydroxyapatites, 209-1 9HYDROXYAPATITEHYDROXYETHYLAMINEKinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withSpectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarhematoporphyrin catalyzed by hydrogenase, 2209-1 1HYDROXYLphases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-3J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 35HYDROXYL(contd)Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisInteraction of hydroxyl groups in NaHY zeolites with physically adsorbed alkanes, 705-10Thermal desorption study of surface hydroxyls on zinc oxide, 728-45of aqueous solutions, 648-53HYDROXYLAMINEThermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 1 52-61HYDROXYLAMMONIUMThermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44HY DROXY METHY LReactions of aliphatic free radicals with copper cations in aqueous solutions.Part 3. Reactions withInorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedInorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedSurface energetics of the wetting of a hydrophobic powder, 2417-3 1Zeolite sorbents. Modification by impregnation with salts, 18&95Physico-chemical characterization of impregnated and ion-exchanged silica-supported nickel oxide,Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 1617-28Raman spectra of indium mono-, di-, and triiodides.Correlation between structure and thermodynamicCapillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofInfluence of dipole interactions on surface reactions, 49-59Spectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Interaction between lysozyme and n-alkyl sulfates in aqueous solution, 654-64Interaction of hydroxyl groups in NaHY zeolites with physically adsorbed alkanes, 705-1 0Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Evidence for modification of nickel oxide by silica.Infrared, electron microscope, and dissolution ratestudies, 1510-19,2 PLATESCapillary phenomena. Part 10. Behavior of grooved rods at fluid/fluid interfaces, 520-7Capillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofinfinite extent meeting solids in a gravitational field, 1419-32Ionic specific adsorption at the metal-solution interface, 1633-9Limiting single-ion molar volumes. Intrinsic volume as a function of the solvent parameters, 2259-84Tube electrode and electron spin resonance.First-order kinetics, 139 1-401Construction of a kinetic model for the iodine iodomethane photodissociation laser. Calculation of crosssections and comparison with experiment, 3 M 2Raman spectra of indium mono-, di-, and triiodides. Correlation between structure and thermodynamicproperties of fused InxI1-x mixtures, 291-301Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Mechanism of the photochemical reaction between ferrocene and iodine, 578-82Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Transport in aqueous solutions of Group IIB metal salts.Part 7. Measurement and prediction of isotopicdiffusion coefficients for iodide in solutions of cadmium iodide, 1052-61Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueoussuspension of titanium dioxide, 1 138-46Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofiodine, 272-9Mechanism of the photochemical reaction between ferrocene and iodine, 578-82cuprous ions: a pulse radiolysis study, 1838-48state absorption and emission spectra, kinetics and energetics, 797-803state absorption and emission spectra, kinetics and energetics, 797-803HYDROXYQUINOLATOPLATINUMHYDROXYQUINOLINEIMMERSIONIMPREGNATION2128-41,l PLATEINDEXINDIUMproperties of fused InxIi-x mixtures, 29 1-301infinite extent meeting solids in a gravitational field, 1419-32INTEGRALINTERACTIONINTERFACEINTRINSICIODATEIODIDEIODIN36 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)IODINE(contd)IODOIND ATEComplex formation between iodine and triphenylstibine oxide, 1689-93Raman spectra of indium mono-, di-, and triiodides. Correlation between structure and thermodynamicConstruction of a kinetic model for the iodine iodomethane photodissociation laser. Calculation of crossSolvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Numerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Secondary ion mass spectra of some simple organic molecules, 549-59Mechanism of the photochemical reaction between ferrocene and iodine, 578-82Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45'C, 637-47Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Calculations on ionic solvation.Part 4. Further calculations in solvation of gaseous univalent ions usingonelayer and twc-layer continuum models, 12 19-3 1New method of separation of the viscosity B-coefficient of the Jones-Dole equation into ioniccontributions for nonaqueous electrolyte solutions, 1275-86Ionic specific adsorption at the metal-solution interface, 1633-9Ionic limiting partial molal volumes in various solvents, 1887-904Physico-chemical characterization of impregnated and ion-exchanged silica-supported nickel oxide,Properties of the borate ion in dilute aqueous solutions, 2179-86Limiting single-ion molar volumes.Intrinsic volume as a function of the solvent parameters, 2259-84Infrared investigation of ionic hydration in ion+xchange membranes. Part 1. Alkaline salts of graftedAdsorption maxima from solutions of ionic surfactants. A thermodynamic analysis, 386-93Ionic liquid mixtures. A modified quasi-lattice theory, 2296-309Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of a , wEnthalpies of proton dissociation of poly(acry1ic acid). Comparison between experiment and theory for aIonic dissociation of aqueous hydrobromic acid.Part 2 Estimate from proton magnetic resonance dataElectrolyte diffusion at very low concentrations in ionized water, 2552-7Spectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Infrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonInfrared spectra of ammonia adsorbed on evaporated germanium films, 489-95Interaction of oxygen with evaporated silicon films. An infrared study, 63&6Interaction of hydroxyl groups in NaHY zeolites with physically adsorbed alkanes, 705-10Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Infrared study of silica immersed in 2,2,4-trimethylpentane + toluene + propionitrile mixtures, 1466-75Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 1476-89Evidence for modification of nickel oxide by silica. Infrared, electron microscope, and dissolution rateAdsorption and activation of ethene by zeolite-H-ZSM-5, 1606-1 6Complex formation between iodine and triphenylstibine oxide, 1689-93Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites.Part 1. Benzene adsorptionSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 2. Hydrogenation ofInteraction of boric acid and borates with carbohydrates and related substances, 1991-2002Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaInfrared study of the solvation of halide ions by water and N-methylacetamide, 2251-8Transformations of but-l-ene molecules adsorbed in NaHY zeolites studied by infrared spectroscopy,Complexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30New Zealand allophanes: a structural study, 2542-51Infrared investigation of ionic hydration in ion-xchange membranes.Part 1. Alkaline salts of graftedproperties of fused InxIl-x mixtures, 291-301sections and comparison with experiment, 30-42Radiation and electron spin resonance study, 244-55IODOMETHANEION2128-41, 1 PLATEpolystyrene sulfonic acid membranes, 2558-74, 1 PLATEIONICIONIZATIONaminocarboxylic acids, 10 1-6polyelectrolyte system, 1287-95at 6-60', 2347-61IONIZEDIRtetrachloride, 302-13studies, 1510-19,2 PLATESon supports, 1942-52adsorbed species, 1953-61immersed in carbon tetrachloride, 2 142-5 12437-47polystyrene sulfonic acid membranes, 2558-74, 1 PLATJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 37IRONInfrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonMagnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Wall-less reactor studies. Part 4. Isobutane pyrolysis, 1694-703Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylDensities of binary liquid mixtures near their consolute points, 2043-5 1Infrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideZeolite sorbents.Modification by impregnation with salts, 180-95Secondary ion mass spectra of some simple organic molecules, 549-59Free radical mechanism in olefin isomerization. Isomerization of (Z)-but-2-ene and (Z)-[ 1,2-Isomerization of cis-but-2kne enhanced by sulfur dioxide adsorbed over decationated-Y and NaYBut-lkne transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Reactions of n-butenes on nickel films, 1547-61Mechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization ofMechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationMechanisms of isomerization of hydrocarbons on metals.Part 1 1. Isomerization and dehydrocyclizationThermal decomposition of cis-2,4dimethyl-trans-3-vinyloxetan, 1849-56Transformations of but-l-ene molecules adsorbed in NaHY zeolites studied by infrared spectroscopy,Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Adsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Wall-less reactor studies. Part 4. Isobutane pyrolysis, 1694-703Mechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in atetrachloride, 302-13ISOBUTANEISOBUTENEradical and of the orientation of hydrogen atom addition to isobutene, 846-51ISOBUTYRICISOCYANATEover chromia/alumina and chromia/silica, 2383-95ISOHEXANEISOMERISOMERIZATION2Hzlethylene over siloxene, 435-41zeolites, 11962052-carbon-1 %labeled 2,3dimethylpentane on a 10% platinum-alumina catalyst, 1704-22of 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34of carbon-1 3-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-562437-47ISOPROPANEISOPROPANOLISOPROPYLISOTHIOCYANATEradiwfreauencv Dulse discharge.1669-76 1 - A " I ISOTOPESolution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compounds196-208 -. - _ _ -Inorganic photophysics in solution. Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Chlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryDiffusion in organic liquids.Part 2. Isotopemass effects in self-diffusion in benzene and cyclohexane,Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-Kinetics of the oxidation of formic acid by aquacobalt(II1) ions in aqueous perchlorate media, 2017-25Temperature-dependent hyperfine coupling constants in electron spin resonance. Part 6. Planar andTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Secondary ion mass spectra of some simple organic molecules, 549-59Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaConstruction of a kinetic model for the iodine iodomethdne photodissociation laser.Calculation of crossed uranyl ion in hydroxylic solvents, 804-1 1and tertiary alkyl chlorides, 838-451030-7lguanidine in acetonitrile and toluene, 1905-10ISOTROPICnonplanar nitroxide radicals, 1296300IXKETONEimmersed in carbon tetrachloride, 2142-51sections and comparison with experiment, 30-42KINETI38 J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980)KINETICSInfluence of dipole interactions on surface reactions, 49-59Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Thermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 152-61Inorganic photophysics in solution.Part 4. Deactivation mechanisms of the 2E, state of chromium(II1)Zeolite sorbents. Modification by impregnation with salts, 180-95Dissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-71Kinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofReaction mechanism of ammonia decomposition on tungsten, 280-90Thermal unimolecular decomposition of 1,1,2,2-tetrafluorocyclobutane, 322-3 1Kinetic study of the reaction of lead metal with hydrogen bromide in the temperature range 448-548 K,Analysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Photochemistry of anhydrides. Part 4. Photolysis of perfluoro-n-butyric anhydride.Reaction ofperfluoropropyl radicals with cyclohexane, 496-502Photochemistry of anhydrides. Part 5. Photolysis of perfluorosuccinic anhydride, 503-1 1Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Mechanism of the photochemical reaction between ferrocene and iodine, 578-82Sorption kinetics of n-hexane on MgA zeolites of different crystal sizes. Study of the rate-limitingtransport mechanism, 597-61 5,2 PLATESAdsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Adsorption equilibrium and kinetics as a function of temperature, 67482Structural interpretation of solvolysis of tert-butyl chloride and tert-butyl bromide in tert-butanol basedon temperature and pressure dependence of rate constants, 753-7Nucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Chlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryand tertiary alkyl chlorides, 838-45Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylradical and of the orientation of hydrogen atom addition to isobutene, 846-51Zeolite RHO.Part 2. Cation exchange equilibriums and kinetics, 1038-5 1Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480°C, 1075-92Reactions of methyl radicals with oxetan, 2-methyloxetan and 2,44imethyloxetan, 1232-9Functional micellar catalysis. Part 3. Quantitative analysis of the catalytic effects due to functionalSeeded emulsion polymerization of styrene, 1323-43Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Primary processes in the low-pressure pyrolysis of methylsilane, 1520-5Solution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,Mechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in aWall-less reactor studies.Part 4. Isobutane pyrolysis, 1694-703Photolysis of copper(I1) oxalato complexes in aqueous solution. Identification and reactions of anBenzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Reactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withThermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites.Part 2. Hydrogenation ofElectroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Kinetics of the oxidation of formic acid by aquacobalt(II1) ions in aqueous perchlorate media, 2017-25Extraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Kinetics of methanol oxidation over platinum wire catalysts, 208495Surface composition and catalytic activity of chromia-alumina catalysts, 2096101Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-complexes from lifetime studies, 162-73iodine, 272-9442-5,1 PLATEmicelles and comicelles, 1301-10alumina and molybdenum disulfide catalysts, 1366-791599-605radio-frequency pulse discharge, 1669-76intermediate, 1779-89ions: a pulse radiolysis study, 1825-37cuprous ions: a pulse radiolysis study, 1838-48lguanidine in acetonitrile and toluene, 1905-10adsorbed species, 1953-61pentyl chloride in water, 21 14-2J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 39KINETICS(contd)Tarnishing kinetics of powders with lognormal particle size distributions, 2229-36Kinetics of the thermal gas-phase decomposition of 2,3-epoxy-l, 1,l-trifluoropropane, 2290-5Reactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Addition of pentenes to slowly reacting mixtures of hydrogen and oxygen at 480", 2396-412Study of molecular sieve carbons. Part 1.Pore structure, gradual pore opening, and mechanism ofBenzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Dynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Capillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofConstruction of a kinetic model for the iodine iodomethane photodissociation laser. Calculation of crossTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Assignment of transient species observed on laser flash photolysis of p-benzoquinone and methylated pAdsorption of small, positive particles onto large, negative particles in the presence of polymer.Part 1.Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Heterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydkatedSolution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsDeviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andlithium titanate-sodium titanate, 2159-69Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( loo), 126-34Solubility of synthetic calcium hydroxyapatites, 209-1 9Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Electroreduction of alkali metal cations. Part 1.Effects of solution composition, 1962-77Analysis of electrical double-layer measurements, 2575-86Kinetic study of the reaction of lead metal with hydrogen bromide in the temperature range 448-548 K,Inorganic photophysics in solution. Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Triplet states of porphyrin esters, 852-9Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inSolubility of synthetic calcium hydroxyapatites, 209-19Evaluation of DebyeHueckel limiting slopes for water between 0 and 1 50°, 19 1 1-16Titanium dioxideelectrolyte interface.Part 2. Surface charge (titration) studies, 9-1 8Improved representation of velocity correlations in aqueous electrolyte solutions, 13 5-5 1Small angle neutron scattering from dilute aqueous dispersions of clay, 314-21Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withDeviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andmolecular sieving, 2457-71,l PLATELACTAMLAMELLARdetermined by neutron diffraction, 234-43LANTHANUM1062-742237-50LAPLACEinfinite extent meeting solids in a gravitational field, 1419-32sections and comparison with experiment, 30-42benzoquinones in aqueous solution, 2432-6Adsorption isotherms, 665-73Adsorption equilibrium and kinetics as a function of temperature, 674-82metal oxides, 1240-62196-208LASERLATEXLATTICELAWLAYERLEAD442-5,1 PLATELEVELed uranyl ion in hydroxylic solvents, 804-1 1LIGHTaqueous solution, 2 187-93LIMELIMITINGLITHIUMsome alkali metal chlorides at 298.15 K, 906-140 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)LITHIUM(contd)LOSSLUMINESCENCElithium titanate-sodium titanate, 21 59-69Thermodynamic study of disorder in lithium bromide monohydrate, 2362-73Dielectric properties of pure liquid N-methylacetamide, 7 1 1-16Inorganic photophysics in solution. Part 4.Deactivation mechanisms of the 2E, state of chromium(II1)Inorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedInorganic photophysics in solution. Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Quenching of the photoluminescence of porous Vycor glass by oxygen and ammonia, 1014-20Photochemistry and exciplex of the uranyl ion in aqueous solution, 1093-1 15Luminescence of porphyrins and metalloporphyrins. Part 1. Zinc(II), nickel(II), and manganese(I1)Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Calorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-Densities of binary liquid mixtures near their consolute points, 2043-51Interaction between lysozyme and n-alkyl sulfates in aqueous solution, 654-64Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltCharacterization of the basicity of oxides through the infrared study of pyrrole adsorption, 147G89Deviations from Vegard’s law in oxide solid solutions. The systems lithium titanate-magnesia andTitanium dioxide-electrolyte interface. Part 2.Surface charge (titration) studies, 9-18Catalytic conversion of alcohols. Part 10. Influence of pretreatment on the selectivity of magnesium andcalcium oxides, 92-100Precise conductimetric studies on aqueous solutions of 2:2 electrolytes.Part 2. Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltoxide-magnesium oxide, 1 147-57Apparent molal volumes of some highly charged electrolytes in water, 2510-1 8Electrolyte diffusion at very low concentrations in ionized water, 2552-7Pulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilDistribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateThermodynamics of dissociation of m-malic, maleic, and fumaric acids in water and water + dioxaneThermodynamics of dissociation of m-malic, maleic, and fumaric acids in water and water + dioxaneLuminescence of porphyrins and metalloporphyrins.Part 1 . Zinc(II), nickel(II), and manganese(I1)Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Interaction of boric acid and borates with carbohydrates and related substances, 1991-2002Adsorption maxima from solutions of ionic surfactants. A thermodynamic analysis, 386-93Implications of elastic deformation on the direct measurement of surface forces, 963-78Cracking of (5-13C)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-9 1Inorganic photophysics in solution. Part 4. Deactivation mechanisms of the 2Eg state of chromium(II1)Free radical mechanism in olefin isomerization.Isomerization of (Ztbut-2-ene and (ZH1,2-complexes from lifetime studies, 162-73state absorption and emission spectra, kinetics and energetics, 797-803ed uranyl ion in hydroxylic solvents, 804-1 1porphyrins, 1978-85I), 2003-10ene photodimer, 21 70-8LUTIDINELYSOZYMEMAGNESIAoxide-magnesium oxide, 1 147-57lithium titanate-sodium titanate, 21 59-69MAGNESIUMMAGNETICsilica, 1455-65MAGNETISM(CoGaXA12-,O4) spinel solid solutions, 244&56mixtures, 21 52-8mixtures, 21 52-8porphyrins, 1978-85MALEICMALICMANGANESEI), 2003-10MANNITOLMAXMEASUREMENTMECHANISMcomplexes from lifetime studies, 162-732Hzlethylene over siloxene, 435-4J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 41MECHANISM(contd)Reactions of n-butenes on nickel films, 1547-61Mechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in aradio-frequency pulse discharge, 1669-76Wall-less reactor studies.Part 4. Isobutane pyrolysis, 1694-703Effect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Inorganic photophysics in solution. Part 4. Deactivation mechanisms of the 2E, state of chromium(II1)Structural analysis of molten silver sulfate, 1185-95Determination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Infrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedCapillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofKinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withMEDIAMEDIUMcomplexes from lifetime studies, 162-73MELTMEMBRANEpolystyrene sulfonic acid membranes, 2558-74, 1 PLATEinfinite extent meeting solids in a gravitational field, 1419-32hematoporphyrin catalyzed by hydrogenase, 2209-1 1MENISCUSMERCAPTOETHANOLMERCURICSome reactions at a mercury(I1) sulfide photoanode, 2587-603MEROCYANINEEffect of solvents on dipole moment of merocyanine, 43-8Small angle neutron scattering from dilute aqueous dispersions of clay, 314-21Homologation of n-alkanes on metal films.A novel aspect of metal-carbene chemistry, 345-56Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 63747Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Gravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminaReactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Ionic specific adsorption at the metal-solution interface, 1633-9Catalytic conversion of alcohols.Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withElectroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Luminescence of porphyrins and metalloporphyrins. Part 1 . Zinc(II), nickel(II), and manganese(I1)Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofIonic liquid mixtures.A modified quasi-lattice theory, 2296-309Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylHeterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedSurface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofHeterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Sorption in partially hydrated NaA and CaA zeolites, 1166-73Application of absolute rate theory to intracrystalline diffusion in zeolites, 1569-75Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aSolvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20.Enthalpies ofMETALcatalysts in their oxidic precursor forms, 929-38the selectivity, 19 17-22porphyrins, 1978-85I), 2003-10ambient gas, 2194-205METHACRYLATEmethacrylate/l-butanethiol, 107-1 1metal oxides, 1240-62polystyrene and poly(dimethy1 siloxane), 1263-74metal oxides, 1240-62METHACRYLICMETHANATION2237-50METHANEmodified proportional counter, 1923-41,2 PLATESRadiation and electron spin resonance study, 244-55transfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9METHANO42 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)METH ANOL(con td)Fieldemission microscopic study of catalytic decomposition of methanol on metal surfaces. Part 1.Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in theThermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Cyanide radical emission in the reaction of active nitrogen with methanol, 1757-65Kinetics of methanol oxidation over platinum wire catalysts, 2084-95Platinum on carbon fiber paper catalysts for methanol electrooxidation. Part 1. Influence of activationTitanium dioxide-electrolyte interface.Part 2. Surface charge (titration) studies, 9-1 8Construction of a kinetic model for the iodine iodomethane photodissociation laser. Calculation of crosssections and comparison with experiment, 3 M 2Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17Dissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-7 1Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 417-25Field-emission microscopic study of catalytic decomposition of methanol on metal surfaces. Part 1.Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Reactions of methyl radicals with oxetan, 2-methyloxetan and 2,4-dimethyloxetan, 1232-9Heterocoagulation. Part 5.Adsorption of a carboxylated polymer latex on monodispersed hydratedInfrared study of silica immersed in 2,2,4-trimethylpentane + toluene + propionitrile mixtures, 1466-75Primary processes in the low-pressure pyrolysis of methylsilane, 1520-5Mechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in aMechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationMechanisms of isomerization of hydrocarbons on metals. Part I 1. Isomerization and dehydrocyclizationMolybdenum-carbon catalysts for reforming reactions, 18 1 1-20Thermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1 849-56Catalytic conversion of alcohols.Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withKinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withDielectric properties of pure liquid N-methylacetamide, 7 1 1-1 6Carbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toEffect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide. VariableInfrared study of the solvation of halide ions by water and N-methylacetamide, 225 1-8Titanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Conductance studies in amide + water mixtures.Part 5. Tetraalkylammonium bromides in N,N-Excitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forDecomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Catalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withMolybdenum+arbon catalysts for reforming reactions, 18 1 1-20Pulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilMechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationMechanisms of isomerization of hydrocarbons on metals. Part 1 1.Isomerization and dehydrocyclizationTungsten, 588-96,2 PLATESmixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24conditions on catalytic activity, 23 10-21METHYLTungsten, 588-96,2 PLATESmetal oxides, 1240-62radio-frequency pulse discharge, 1669-76of 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34of carbon- 13-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-56the selectivity, 1917-22hematoporphyrin catalyzed by hydrogenase, 2209-1 1METHYLACETAMIDEamides, 1008-1 3temperature proton magnetic resonance study, 1 131-7METHYLAMMONIUMdetermined by neutron diffraction, 23W3dimethylacetamide + water mixtures at 35", 1409-1 8aromatic amines, 1576-84METHYLANILINEMETHYLBUTANEMETHYLBUTANOLthe selectivity, 1917-22METHYLCYCLOPENTANEMETHY LDISILOXANEsilica, 1455-65of 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34METHYLHEXANJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 43METHY LHEXANE(contd)METHY LOXETANMETHYLPENTANEof carbon-13-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-56Reactions of methyl radicals with oxetan, 2-methyloxetan and 2,4-dimethyloxetan, 1232-9Infrared study of silica immersed in 2,2,4trimethylpentane + toluene + propionitrile mixtures, 146675Mechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization ofComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-molybdenum trioxide-alumina catalyst, 1356-65Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 812-24METHYLPYRROLINEOXIDEElectron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisof aqueous solutions, 648-53Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Primary processes in the low-pressure pyrolysis of methylsilane, 1520-52-carbon-13-labeled 2,34methylpentane on a 10% platinum-alumina catalyst, 1704-22METHYLPHOSPHINEMETHYLPROPENEMETHYLPY RROLIDONEMETHY LSILANEMETHYLVINYLOXETANEThermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56MICELLEAdsorption maxima from solutions of ionic surfactants.A thermodynamic analysis, 386-93Numerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Functional micellar catalysis. Part 3. Quantitative analysis of the catalytic effects due to functionalmicelles and comicelles, 1301-10Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylacetate, 1857-67, 1 PLATEAggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneosmometry, 2035-42Thermodynamics of micellization and solubilization in the system water + sodium n-octanoate + n-pentanol at 25°C.Part 1. Partial molar enthalpies, 473-88Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal DhaseMICELLIZATIONMICROMICROEMULSIONMICROPROBEin NaY zeolite, 403-16,2 PLATESMICROSCOPYRedox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phaseMILLINGEffects of wet vibro-milling on the polymorphic conversion of aragonite into calcite, 790-6,2 PLATESMIXINGEnthalpy of mixing of liquid hydrogen chloride and liquid xenon. Comparison of experiment and theory174-9Thermodynamics of micellization and solubilization in the system water + sodium n-ctanoate + n-pentanol at 25°C. Part 1.Partial molar enthalpies, 473-88Thermodynamic functions for the system ethanol + pxylene from vapor pressures, enthalpies of mixingand volume of mixing and their interpretation in terms of association, 537-48Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Aqueous solutions containing amino acids and peptides.Part 10. Enthalpy of interaction of glycine withsome alkali metal chlorides at 298.15 K, 90614Enthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,208C3Ionic liquid mixtures. A modified quasi-lattice theory, 2296309Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496506Thermodynamic functions for the system ethanol + p-xylene from vapor pressures, enthalpies of mixingInfrared study of silica immersed in 2,2,4-trimethylpentane + toluene + propionitrile mixtures, 146675in NaY zeolite, 403-16,2 PLATESMIXTand volume of mixing and their interpretation in terms of association, 537-444 J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980)MIXT(contd)Densities of binary liquid mixtures near their consolute points, 2043-5 1Ionic liquid mixtures. A modified quasi-lattice theory, 2296-309Theory of adsorption from multicomponent liquid mixtures on solid surfaces and its application to liquidAdsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Tritium recoil ranges and their influence on the helium moderator anomaly, 860-8Superacidity of modified y-alumina. Structure of active site and catalytic activity, 131 1-22Structural properties of antimony and tin mixed oxide catalysts, 1652-9New Zealand allophanes: a structural study, 2542-51Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Partial molar volumes of organic compounds in water.Part 7. Sodium and hydrochloride salts of a , wInvestigation of the self-association of an amphiphilic drug in aqueous solution, 570-7Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inElectron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofStudy of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofStudy of molecular sieve carbons. Part 2. Estimation of cross-sectional diameters of nonsphericalMolecular sieving range of pore diameters of adsorbents, 2507-9Ionic limiting partial molal volumes in various solvents, 1887-904Apparent molal volumes of some highly charged electrolytes in water, 2510-18Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfatezinc sulfate, 16 17-28Properties of the borate ion in dilute aqueous solutions, 2179-86Limiting single-ion molar volumes.Intrinsic volume as a function of the solvent parameters, 2259-84Homologation of n-alkanes on metal films. A novel aspect of metal-carbene chemistry, 345-56Studies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Gravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminacatalysts in their oxidic precursor forms, 929-38Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Essential factors for catalysis and reaction mechanisms, 939-5 1Genesis, nature and dispersion of active phase in sulfided cobalt-molybdenumly-alumina hydrodesulfur-ization catalysts.Investigation by analytical electron microscopy and x-ray photoelectron spectroscop-Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-molybdenum trioxide-alumina catalyst, 1356-65Hydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-alumina and molybdenum disulfide catalysts, 1366-79Hydrogen sorption by molybdenum sulfide catalysts, 1585-98Molybdenum-carbon catalysts for reforming reactions, 18 1 1-20Effect of sodium on the cobalt-molybdenumly-alumina system.Part 2. Influence of sodium content andpreparation methods on the state of dispersion and nature of molybdenum supported on y-alumina,adsorption chromatography, 2486-95Adsorption isotherms, 665-73MOBILITYMODERATORMODIFICATIONMOESSBAUERMOLaminocarboxylic acids, 101-6aqueous solution, 2 187-93ambient gas, 2194-205molecular sieving, 2457-71, 1 PLATEmolecules, 2472-85MOLALMOLARMOLYBDENUMy, 988-97,2 PLATES2052-64, 1 PLATEMONOHYDRATEThermodynamic study of disorder in lithium bromide monohydrate, 2362-73Use of the Gibbs equation to calculate adsorption into monolayer-covered surfaces, 118-25MONOLAY ERMONOMERIZATIONCalorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9-cyanoanthrac-Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andChemisorption of carbon monoxide on tungsten( 1 10) and tungsten(320) adsorption, desorption and stateene photodimer, 2170-8nickelsopper catalysts containing preadsorbed carbon monoxide, 5 12-1 9interconversion, 758-73MONOXIDJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 45MONOXIDE(contd)Magnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andFormation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltSpectroscopic study of anatase properties.Part 3. Surface acidity, 2102-13Infrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxidedecomposition of nitric oxide, 1 1 16-2 1oxide-magnesium oxide, 1 147-57over chromia/alumina and chromia/silica, 2383-95MONTMORILLONITEInvestigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensions225-35Small angle neutron scattering from dilute aqueous dispersions of clay, 3 1421Thermochemistry of hydroxylammonium and hydrazonium zeolites, 3 3 2 4Theory of adsorption from multicomponent liquid mixtures on solid surfaces and its application to liquidDetermination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarSmall angle neutron scattering from dilute aqueous dispersions of clay, 31421Hydrogen sorption by molybdenum sulfide catalysts, 1585-98MORDENITEMULTICOMPONENTadsorption chromatography, 2486-95phases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36NAPHTHALENENEUTRONNEWNew Zealand allophanes: a structural study, 2542-5 1NICKELNumerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Volumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on supported nickel andGas-chromatographic studies of hydrocarbon hydrogenolysis on a nickel-silica catalyst, 683-700Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Surface state and catalytic activity and selectivity of nickel catalysts in hydrogenation reactions.Part 2.Surface characterization of Raney nickel and Urushibara nickel catalysts by x-ray photoelectronspectroscopy, 998- 1007Evidence for modification of nickel oxide by silica. Infrared, electron microscope, and dissolution ratestudies, 1510-19,2 PLATESFerromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34Reactions of n-butenes on nickel films, 1547-61Joint studies by x-ray photoelectron spectroscopy and analytical electron microscopy of the dispersion ofnickel oxide supported on silica and silica-aluminas, 1766-72Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-nickekopper catalysts containing preadsorbed carbon monoxide, 5 12-19I), 2003-10Physicoshemical characterization of impregnated and ion-exchanged silica-supported nickel oxide,212841.1 PLATEVolumetric and calorimetric study of the adsorption of hydrogen, at 296 K, on silica-supported nickelDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Tracer studies of retained hydrogen and surface residues on nickel catalysts.Isotopic exchange andComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Homologation of n-alkanes on metal films. A novel aspect of metal-carbene chemistry, 345-56and nickel-copper catalysts, 2221-82237-50reactivity toward ethylene, 2322-34NIOBIUMNITRATESalting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,1062-74Determination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1 4 1Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andInfrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideReaction mechanism of ammonia decomposition on tungsten, 280-90Electron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogenNITRICdecomposition of nitric oxide, 11 16-21over chromia/alumina and chromia/silica, 2383-95NITRIDEcompounds and olefins, 1490-5046 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)NITRONitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andNitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andNitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andNitrobenzenes: a comparison of pulse radiolytically determined one-electron reduction potentials andTitanium dioxide-electrolyte interface. Part 1. Gas adsorption and tritium exchange studies, 1-8Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Reaction mechanism of ammonia decomposition on tungsten, 280-90Thermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-81Cyanide radical emission in the reaction of active nitrogen with methanol, 1757-65Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aElectron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofStudy of molecular sieve carbons.Part 1. Pore structure, gradual pore opening, and mechanism ofKinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-Tube electrode and electron spin resonance.First-order kinetics, 139 1-401Functional micellar catalysis. Part 3. Quantitative analysis of the catalytic effects due to functionalKinetic isotope effect and tunneling in the reaction between 4nitrophenylnitromethane and pentamethy-Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Analysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Temperature-dependent hyperfine coupling constants in electron spin resonance.Part 6. Planar andSpectroscopic studies of water-aprotic solvent interactions in the water-rich region, 25645Carbon-1 3 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toEffect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide. VariablePulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilComparison of predicted and nuclear magnetic resonance zeolitic diffusion coefficients, 1 562-8Adsorption and activation of ethene by zeoliteH-ZSM-5, 1606-1 6Proton nuclear magnetic resonance studies of the hydrolysis of the tetraaquaberyllium dication, 22 12-20Cracking of (5-WEn-nonane with quartz wool, silica-alumina and type Y zeolite, 84-91New method of separation of the viscosity %coefficient of the Jones-Dole equation into ionicInorganic photophysics in solution.Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Study of molecular sieve carbons. Part 2. Estimation of cross-sectional diameters of nonsphericalcalculated electron affinities, 1402-8calculated electron affinities, 1402-8calculated electron affinities, 1402-8calculated electron affinities, 1402-8NITROBENZALDEHYDENITROBENZENENITROBENZONITRILENITROGENmodified proportional counter, 1923-41,2 PLATESambient gas, 2 194-205molecular sieving, 2457-71, 1 PLATElguanidine in acetonitrile and toluene, 1905-10NITROMETHANENITROPHENOLNITROPHENY Lmicelles and comicelles, 1301-10lguanidine in acetonitrile and toluene, 1905-10lguanidine in acetonitrile and toluene, 1905-10NITROPHENY LNITROMETHANENITROSYLNITROUSEssential factors for catalysis and reaction mechanisms, 939-5 1NITROXIDEnonplanar nitroxide radicals, 1296300NMRamides, 1008-1 3temperature proton magnetic resonance study, 1 1 31-7silica, 1455-65NONANENONAQNONRADIATIVEcontributions for nonaqueous electrolyte solutions, 1275-86ed uranyl ion in hydroxylic solvents, 804-1 1NONSPH E RI CAJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 47NONSPHERICAL(contd)molecules, 2472-85NONSTOICHIOMETRY196-208NORBORNENESolution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsElectron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogenStructure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Thermodynamics of micellization and solubilization in the system water + sodium n-ctanoate + n-Catalytic conversion of alcohols.Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withcompounds and olefins, 1490-509determined by neutron diffraction, 2 3 H 3pentanol at 25°C. Part 1. Partial molar enthalpies, 473-88the selectivity, 1917-22OCTANOATEOCTANOLOFFRETITEBut-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7OLEFINElectron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogenFormation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltTransformations of but-l-ene molecules adsorbed in NaHY zeolites studied by infrared spectroscopy,Benzophenone triplet properties in acetonitrile and water.Reduction by lactams, 1800-10Luminescence of porphyrins and metalloporphyrins. Part 1 . Zinc(II), nickel(II), and manganese(I1)Determination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Evaluation of Debye-Hueckel limiting slopes for water between 0 and 150", 191 1-16Aggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membranePhotolysis of copper(I1) oxalato complexes in aqueous solution. Identification and reactions of anReactions of methyl radicals with oxetan, 2-methyloxetan and 2,4-dimethyloxetan, 1232-9Thermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Adsorption and decomposition of isopropyl alcohol over zinc oxide.Infrared and kinetic study, 19-29Catalytic conversion of alcohols. Part 10. Influence of pretreatment on the selectivity of magnesium andInfrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonRaman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394-402Analysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Thermal desorption study of surface hydroxyls on zinc oxide, 728-45Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-8 1Studies of hydrogen spillover.Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Gravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenum,$-aluminacatalysts in their oxidic precursor forms, 929-38Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Essential factors for catalysis and reaction mechanisms, 939-5 1Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-62Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption anddecomposition of nitric oxide, 1 1 16-21Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltoxide-magnesium oxide, 1 147-57Sorption in partially hydrated NaA and CaA zeolites, 1166-73Structures of tin oxide-antimony oxide catalysts, 1174-82,2 PLATESUse of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-compounds and olefins, 149s509oxide-magnesium oxide, 1 147-572437-47OLIGOMERIZATIONOPTICALORBITporphyrins, 1978-85OSCILLATINGOSMOTICosmometry, 2035-42intermediate, 1779-89OXALATEOXETANOXETANEOXIDEcalcium oxides, 92- 100tetrachloride, 302-13Adsorption isotherms, 665-748 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)OXIDE(contd)molybdenum trioxide-alumina catalyst, 135665alumina and molybdenum disulfide catalysts, 1 36679studies, 1510-19,2 PLATESHydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 1476-89Evidence for modification of nickel oxide by silica.Infrared, electron microscope, and dissolution rateStructural properties of antimony and tin mixed oxide catalysts, 1652-9Complex formation between iodine and triphenylstibine oxide, 1689-93Joint studies by x-ray photoelectron spectroscopy and analytical electron microscopy of the dispersion ofCatalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withSpectroscopic study of anatase properties.Part 3. Surface acidity, 2102-1 3Physico-chemical characterization of impregnated and ion-xchanged silica-supported nickel oxide,Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,nickel oxide supported on silica and silica-aluminas, 1766-72the selectivity, 19 17-222128-41,l PLATEambient gas, 2194-2052237-50Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumoxide. 2335-46Infrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideStudy of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofThermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Extended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-6 1Redox behavior of transition metal ions in zeolites.Part 8. Characterization of a ruthenium metal phaseMechanism of the photochemical reaction between ferrocene and iodine, 578-82Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480"C, 1075-92Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousStructural properties of antimony and tin mixed oxide catalysts, 1652-9Kinetics of the oxidation of formic acid by aquacobalt(II1) ions in aqueous perchlorate media, 2017-25Kinetics of methanol oxidation over platinum wire catalysts, 2084-95Platinum on carbon fiber paper catalysts for methanol electrooxidation.Part 1. Influence of activationReactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Infrared spectroscopic study of isocyanate formation in the reaction of nitric oxide and carbon monoxideAddition of pentenes to slowly reacting mixtures of hydrogen and oxygen at 480°, 2396412Kinetics of the thermal gas-phase decomposition of 2,3-epoxy-l, 1, 1-trifluoropropane, 2290-5Pressure and temperature dependence of the self-diffusion coefficient of water and oxygen-1 8 water,Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 417-25Interaction of oxygen with evaporated silicon films.An infrared study, 630-6Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Triplet states of porphyrin esters, 852-9Quenching of the photoluminescence of porous Vycor glass by oxygen and ammonia, 1014-20Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480"C, 1075-92Catalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withExodectron emission from platinum wires cooling in hydrocarbons and other gases as observed in aReactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Study of molecular sieve carbons.Part 1. Pore structure, gradual pore opening, and mechanism ofMolecular sieving range of pore diameters of adsorbents, 2507-9Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86over chromia/alumina and chromia/silica, 2383-95molecular sieving, 2457-7 1, 1 PLATEOXIDNin NaY zeolite, 403-16,2 PLATESEssential factors for catalysis and reaction mechanisms, 939-5 1suspension of titanium dioxide, 1 138-46conditions on catalytic activity, 231CL21over chromia/alumina and chromia/silica, 2383-95OXIRANEOXYGEN377-85the selectivity, 19 17-22modified proportional counter, 1923-41,2 PLATESmolecular sieving, 2457-71, 1 PLATEPACKINJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 49PAIRMechanism of the Dhotochemical reaction between ferrocene and iodine, 578-82Thermodynamic &dies of cryptand 222 and cryptates in water and methanol, 869-84PALLADIUMSolution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsStudies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andState of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossSurface composition of palladium-gold alloys, 1388-90Enthalpy of hydrogen in palladium alloys at constant interstitial volume, 2285-9Redox behavior of transition metal ions in zeolites.Part 8. Characterization of a ruthenium metal phaseAdsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Tarnishing kinetics of powders with lognormal particle size distributions, 2229-36Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingThermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Relative scale of free energy of transfer of anions from water to 1,24ichloroethane, 1663-8Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inDissociation of lY3-hexadiene and the resonance energy of the pentadienyl radical, 266-71Kinetic isotope effect and tunneling in the reaction between 4nitrophenylnitromethane and pentamethy-Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-Secondary ion mass spectra of some simple organic molecules, 549-59Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480"C, 1075-92Infrared study of silica immersed in 2,2,&trimethylpentane + toluene + propionitrile mixtures, 1466-75Mechanism of isomerization of hydrocarbons on metals.Part 9. Isomerization and dehydrocyclization of2-carbon-13-labeled 2,3-dimethylpentane on a 10% platinum-alumina catalyst, 1704-22Thermodvnamics of micellization and solubilization in the svstem water + sodium n-octanoate + n-196-208decomposition of nitric oxide, 11 16-21spectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30PARTICLEin NaY zeolite, 403-16,2 PLATESAdsorption equilibrium and kinetics as a function of temperature, 674-82PARTICLESAdsorption isotherms, 665-73upper consolute temperatures, 362-7PARTITIONPAVATRINEaqueous solution, 2187-93PENTADIENYLPENTAMETHYLlguanidine in acetonitrile and toluene, 1905-10lguanidine in acetonitrile and toluene, 1905-10PENTAMETHY LGUANIDINEPENTANEPENTANOLpentand at 25°C.Part 1. Partial molar enthalpies, 47>88 ,PENTANONESecondary ion mass spectra of some simple organic molecules, 549-59Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaStudies of hydrogen spillover. Part 4.Factors affecting hydrogen spillover and its reversal, 889-900Addition of pentenes to slowly reacting mixtures of hydrogen and oxygen at 480", 2396-412Addition of pentenes to slowly reacting mixtures of hydrogen and oxygen at 480", 2396-412Effect of temperature on the specific heat of activation for the solvolysis of tert-butyl chloride and tert-Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylModerated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylimmersed in carbon tetrachloride, 2142-51PENTENEPENTENYLPENTYLpentyl chloride in water, 21 14-23PENTYLBUTYLAMMONIUMPENULTIMATEmethacrylate/l-butanethiol, 107-1 1acrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17PERCHLORATESolvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems50 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)PERCHLORATE(c0ntd)Radiation and electron spin resonance study, 244-55mixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in theThermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Photochemistry of anhydrides. Part 4.Photolysis of perfluoro-n-butyric anhydride. Reaction ofPhotochemistry of anhydrides. Part 5. Photolysis of perfluorosuccinic anhydride, 503-1 1Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Photoadsorption and photodesorption of oxygen on highly hydroxylated titania surfaces. Part 3. Role ofEffect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Enthalpy of mixing of liquid hydrogen chloride and liquid xenon. Comparison of experiment and theoryElectron transfer at alumina surfaces. Part 6. Redox properties of fluorided aluminas, 202634Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofTitanium dioxide4ectrolyte interface.Part 2. Surface charge (titration) studies, 9-1 8Effects of wet vibremilling on the polymorphic conversion of aragonite into calcite, 790-6,2 PLATESSolid-solid phase transitions in azoxy compounds, 198690Deviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andThermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 152-61Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumIonic viscosity B coefficients in dimethyl sul.foxide at 25,35 and 45"C, 637-47Tube electrode and electron spin resonance. First-order kinetics, 1391-40 1Excitation energy effects on the fluorescence quantum yield in solution.Deactivation pathways forInelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumThermal decomposition of solid chromium(II1) tris(N-benzoyl-N-phenylhydroxylamine), 1 52-6 1Luminescence of porphyrins and metalloporphyrins. Part 1 . Zinc(II), nickel(II), and manganese(I1)Complex formation between iodine and triphenylstibine oxide, 1689-93Dehydration-dehydrogenation selectivity of butan-2-1 on cadmium phosphate catalysts, 746-52Solution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Luminescence of porphyrins and metalloporphyrins.Part 1. Zinc(II), nickel(II), and manganese(I1)Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Solubility of synthetic calcium hydroxyapatites, 209-1 9Mechanism of the photochemical reaction between ferrocene and iodine, 578-82Heterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousPERFLUOROperfluoropropyl radicals with cyclohexane, 496-502PERFLUOROOCTANOATEdetermined by neutron diffraction, 23643hydrogen peroxide in photodesorption of oxygen, 1535-46PEROXIDEPEROXYPERTURBATION174-9PERYLENEambient gas, 2194-205PHPHASElithium titanate-sodium titanate, 21 59-69PHENYLPHENYLAMINEoxide, 2335-46PHENYLBORATEPHENYLENEDIAMINEPHENYLETHYLAMINEaromatic amines, 1576-84oxide, 2335-46PHENY LHY DROXY LAMINEPHENYLPORPHINEporphyrins, 1978-85PHENY LSTIBINEPHOSPHATEPHOSPHIDE196-208PHOSPHINEPHOSPHORESCENCEporphyrins, 1978-85I), 2003-10PHOSPHORICPHOTOCHEJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 51PHOTOCHEM(contd)suspension of titanium dioxide, 1138-46hematoporphyrin catalyzed by hydrogenase, 2209-1 1Benzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withPHOTOCURRENTSome reactions at a mercury(I1) sulfide photoanode, 2587-603PHOTODIMERCalorimetric, spectroscopic, and structural studies of the monomerization of crystalline 9<yanoanthrac-Some reactions at a mercury(1I) sulfide photoanode, 2587-603Construction of a kinetic model for the iodine iodomethane photodissociation laser.Calculation of crossTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Photochemistry of anhydrides. Part 4. Photolysis of perfluoro-n-butyric anhydride. Reaction ofPhotochemistry of anhydrides. Part 5. Photolysis of perfluorosuccinic anhydride, 503-1 1Photoadsorption and photodesorption of oxygen on highly hydroxylated titania surfaces. Part 3. Role ofExcitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forPhotolysis of copper(I1) oxalato complexes in aqueous solution. Identification and reactions of anAssignment of transient species observed on laser flash photolysis of pbenzoquinone and methylated pHeterogeneous photocatalysis. Oxidation of halide ions by oxygen in ultraviolet irradiated aqueousBenzophenone triplet properties in acetonitrile and water.Reduction by lactams, 1800-10Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withElectron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofSolid-solid phase transitions in azoxy compounds, 1986-90Small angle neutron scattering from dilute aqueous dispersions of clay, 314-21Homologation of n-alkanes on metal films. A novel aspect of metal-carbene chemistry, 345-56Extended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-6 1Hydrogen adsorption on platinum catalysts.Quantitative determination of the various speciesMagnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Inorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedStudies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Reactions of alkanes and cycloalkanes on platinum-gold alloy films, 1640-5 1Mechanism of isomerization of hydrocarbons on metals. Part 9. Isomerization and dehydrocyclization ofMechanism of isomerization of hydrocarbons on metals. Part 10. Isomerization and dehydrocyclizationMechanisms of isomerization of hydrocarbons on metals. Part 1 1.Isomerization and dehydrocyclizationExo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 2. Hydrogenation ofKinetics of methanol oxidation over platinum wire catalysts, 2084-95Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withPlatinum on carbon fiber paper catalysts for methanol electrooxidation. Part 1. Influence of activationFreezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-ene photodimer, 21 70-8PHOTOELECTROCHEMPHOTOLYSISsections and comparison with experiment, 30-42perfluoropropyl radicals with cyclohexane, 496-502hydrogen peroxide in photodesorption of oxygen, 1535-46aromatic amines, 1576-84intermediate, 1779-89benzoquinones in aqueous solution, 2432-6suspension of titanium dioxide, 1138-46PHOTOOXIDNPHOTOPHYSPHOTOSENSITIZERhematoporphyrin catalyzed by hydrogenase, 2209-1 1ambient gas, 219&205PHTHALOCYANINEPLASTICPLATELETPLATINUMpopulation, 616-29state absorption and emission spectra, kinetics and energetics, 797-8032-carbon-13-labeled 2,34methylpentane on a 10% platinum-alumina catalyst, 1704-22of 2-carbon-13-labeled 2-methylhexane on a 10% platinum-alumina catalyst, 1723-34of carbon-13-labeled 3-methylhexanes on platinum-alumina catalysts, 1735-56modified proportional counter, 192341,2 PLATESadsorbed species, 1953-61hematoporphyrin catalyzed by hydrogenase, 2209-1 1conditions on Catalytic activity, 23 10-21POIN52 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)POINT(contd)dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Densities of binary liquid mixtures near their consolute points, 2043-51Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andState of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossGlass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 1617-28Enthalpies of proton dissociation of poly(acry1ic acid). Comparison between experiment and theory for apolyelectrolyte system, 1287-95Thermodynamic properties of polyelectrolyte solutions.Part 2. Influence of the polyelectrolyte chargedensity, 1790-800Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ l-butanethiol and some general considerati-ons, 112-17Heterocoagulation. Part 5. Adsorption of a carboxylated polymer latex on monodispersed hydratedmetal oxides, 124&62Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylacetate, 1857-67, 1 PLATESurface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Raman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394-402Seeded emulsion polymerization of styrene, 1323-43Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Solution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,POISONINGdecomposition of nitric oxide, 11 16-21spectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30POLARIZATIONPOLYACRYLICPOLYELECTROLYTEPOLYMERPOLYMETHYLPOLYMN1599-605POLYMORPHEffects of wet vibro-milling on the polymorphic conversion of aragonite into calcite, 79M, 2 PLATESPOLYSTYRENEAdsorption of small, positive particles onto large, negative particles in the presence of polymer.Part 1.Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofInfrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedAdsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 1.Adsorption of small, positive particles onto large, negative particles in the presence of polymer. Part 2.Study of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofMolecular sieving range of pore diameters of adsorbents, 2507-9New Zealand allophanes: a structural study, 2542-51Titanium dioxide-electrolyte interface.Part 1. Gas adsorption and tritium exchange studies, 1-8Luminescence of porphyrins and metalloporphyrins. Part 1. Zinc(II), nickel(II), and manganese(I1)Triplet states of porphyrin esters, 852-9Titanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Zeolite sorbents. Modification by impregnation with salts, 180-95Small angle neutron scattering from dilute aqueous dispersions of clay, 3 14-21Aqueous solutions containing amino acids and peptides. Part 10. Enthalpy of interaction of glycine withAdsorption isotherms, 665-73Adsorption equilibrium and kinetics as a function of temperature, 674-82polystyrene and poly(dimethy1 siloxane), 1263-74polystyrene sulfonic acid membranes, 2558-74, 1 PLATEAdsorption isotherms, 665-73Adsorption equilibrium and kinetics as a function of temperature, 674-82molecular sieving, 2457-71, 1 PLATEPOLYVINYLPOREPOROSITYPORPHINEporphyrins, 1978-85PO WHY RINPOTASSIUJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 53POTASSIUM(contd)some alkali metal chlorides at 298.15 K, 90614Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 1617-28Apparent molal volumes of some highly charged electrolytes in water, 25 1@-18Determination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Electromotive force studies of electrolytic dissociation.Part 13. Dissociation constants of someAnalysis of electrical double-layer measurements, 2575-86POTENTIALdicarboxylic acids at zero ionic strength in water and 10% ethanol, 1773-8POTENTIOMETRICAnalysis of electrical double-layer measurements, 2575-86POWDERTarnishing kinetics of powders with lognormal particle size distributions, 2229-36Surface energetics of the wetting of a hydrophobic powder, 2417-31Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Use of the Gibbs equation to calculate adsorption into monolayer-covered surfaces, 1 18-25Thermodynamic functions for the system ethanol + p-xylene from vapor pressures, enthalpies of mixingAggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneThermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Catalytic conversion of alcohols.Part 10. Influence of pretreatment on the selectivity of magnesium andChlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryInfrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaMagnetic, infrared and catalytic studies of platinum-iron/silica catalysts, 782-9Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Use of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-Structural properties of antimony and tin mixed oxide catalysts, 1652-9Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide.Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Reactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricions: a pulse radiolysis study, 1825-37Infrared study of silica immersed in 2,2,&trimethylpentane + toluene + propionitrile mixtures, 1466-75Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aPhotochemistry of anhydrides. Part 4. Photolysis of perfluoro-n-butyric anhydride.Reaction ofNucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in theEffect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Titanium dioxide-electrolyte interface. Part 1. Gas adsorption and tritium exchange studies, 1-8Infrared study of the adsorption of N,Ncliethylacetamide and three N,N-diethylaminoketones on silicaimmersed in carbon tetrachloride, 2 142-5 1Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-lguanidine in acetonitrile and toluene, 1905-10PREFERENTIAL1062-74PRESSUREand volume of mixing and their interpretation in terms of association, 537-48osmometry, 2035-42PRETREATMENTcalcium oxides, 92-100and tertiary alkyl chlorides, 838-45immersed in carbon tetrachloride, 2142-5 1PROPANEPROPANONEPROPENEEssential factors for catalysis and reaction mechanisms, 939-5 1molybdenum trioxide-alumina catalyst, 135M5PROPIONAMIDEPROPION ATEPROPIONITRILEPROPORTIONALmodified proportional counter, 192341,2 PLATESperfluoropropyl radicals with cyclohexane, 496502mixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24PROPYLPROPY LENEPROTICPROTONPROTON ATIO54 J.C.S.FARADAY I SUBJECT INDEX VOL.76 (1980)PROTOPORPHYRINPSEUDOPLASTICITYTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Investigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsThermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Spectroscopic study of anatase properties. Part 3. Surface acidity, 2102-13Dissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-7 1Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Thermal transformation of goethite into hematite in alkali halide disks, 1442-54Primary processes in the low-pressure pyrolysis of methylsilane, 1520-5Wall-less reactor studies. Part 4. Isobutane pyrolysis, 1694-703Thermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1 849-56225-35PY RIDINEPYROLYSISPYRROLECharacterization of the basicity of oxides through the infrared study of pyrrole adsorption, 1476-89OUANTUM .Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Excitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forCracking of (5-W)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-91Relative scale of free energy of transfer of anions from water to 1,24ichloroethane, 1663-8Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Triplet states of porphyrin esters, 852-9Quenching of the photoluminescence of porous Vycor glass by oxygen and ammonia, 101420Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Construction of a kinetic model for the iodine iodomethane photodissociation laser.Calculation of crosssections and comparison with experiment, 30-42Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylmethacrylate/l-butanethiol, 107-1 1Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17Free radical mechanism in olefin isomerization.Isomerization of (Z)-but-2-ene and (ZH1,2-2Hzlethylene over siloxene, 435-41Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisof aqueous solutions, 648-53Formation of polymeric radical anions by adsorption of carbon monoxide on high surface area cobaltoxidemagnesium oxide, 1 147-57Reactions of methyl radicals with oxetan, 2-methyloxetan and 2,4-dimethyloxetan, 1232-9Tube electrode and electron spin resonance. First-order kinetics, 1391-401Electron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogenSolution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,Wall-less reactor studies.Part 4. Isobutane pyrolysis, 1694-703Reactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withEffect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Solvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Radiation and electron spin resonance study, 24455Analysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 49-56Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases.Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Mechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in aradio-frequency pulse discharge, 1669-76aromatic amines, 1576-84QUARTZQUATERNARYQUENCHINGI), 2003-10RADIATIONRADICALcompounds and olefins, 1490-5091599-605ions: a pulse radiolysis study, 1825-37cuprous ions: a pulse radiolysis study, 1838-48RADIOLY SIJ.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 55RADIOLYSIS(contd)Photolysis of copper(I1) oxalato complexes in aqueous solution. Identification and reactions of anReactions of aliphatic free radicals with copper cations in aqueous solution.Part 2. Reactions with cupricReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withRaman spectra of indium mono-, di-, and triiodides. Correlation between structure and thermodynamicRaman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394402Surface state and catalytic activity and selectivity of nickel catalysts in hydrogenation reactions. Part 2.Surface characterization of Raney nickel and Urushibara nickel catalysts by x-ray photoelectronspectroscopy, 998-1007intermediate, 1779-89ions: a pulse radiolysis study, 1825-37cuprous ions: a pulse radiolysis study, 183848properties of fused InxIl-x mixtures, 291-301RAMANRANEYRANGERATERAYTritium recoil ranges and their influence on the helium moderator anomaly, 860-8Extraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Extended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-6 1Redox behavior of transition metal ions in zeolites.Part 8. Characterization of a ruthenium metal phaseRelaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55New Zealand allophanes: a structural study, 2542-5 1Adsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Influence of dipole interactions on surface reactions, 49-59Kinetic study of the reaction of lead metal with hydrogen bromide in the temperature range 448-548 K,Temperature dependence of the disproportionation/combination ratio for hydrogen atom + tert-butylradical and of the orientation of hydrogen atom addition to isobutene, 846-5 1Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Essential factors for catalysis and reaction mechanisms, 939-5 1Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Addition of n-pentane to slowly reacting mixtures of hydrogen + oxygen at 480*C, 1075-92Functional micellar catalysis.Part 3. Quantitative analysis of the catalytic effects due to functionalHydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Primary processes in the low-pressure pyrolysis of methylsilane, 1520-5Reactions of n-butenes on nickel films, 1547-61Solution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,Reactions of alkanes and cycloalkanes on platinum-gold alloy films, 1640-5 1Cyanide radical emission in the reaction of active nitrogen with methanol, 1757-65Tarnishing kinetics of powders with lognormal particle size distributions, 2229-36Tracer studies of retained hydrogen and surface residues on nickel catalysts.Isotopic exchange andTritium recoil ranges and their influence on the helium moderator anomaly, 860-8Photochemistry of anhydrides. Part 4. Photolysis of perfluoro-n-butyric anhydride.Reaction ofDetermination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarSolution of the recursion equations for emulsion polymerization kinetics in the nonstationary state,Gravimetric study of reduction by hydrogen of hydrodesulfurization cobalt-molybdenumly-aluminaFerromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-Reactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withElectroreduction of alkali metal cations. Part 1. Effects of solution composition, 1962-77Surface composition and catalytic activity of chromia-alumina catalysts, 2096-10 1Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light within NaY zeolite, 403-1 6,2 PLATESREACTION442-5, 1 PLATEmicelles and comicelles, 1301-10alumina and molybdenum disulfide catalysts, 1 366-791599-605reactivity toward ethylene, 2322-34RECOILRECOMBINATIONperfluoropropyl radicals with cyclohexane, 496-502phases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36RECURSION1599-605REDNcatalysts in their oxidic precursor forms, 929-38exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34cuprous ions: a pulse radiolysis study, 1838-456 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)REDN(contd)REDOXREFLECTIONhematoporphyrin catalyzed by hydrogenase, 2209-1 1Electron transfer at alumina surfaces. Part 6.Redox properties of fluorided aluminas, 2026-34Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Molybdenum+arbon catalysts for reforming reactions, 18 1 1-20Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 161 7-28How much may the equilibrium be shifted in a chemical relaxation experiment?, 583-7Pulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilDissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-71Ferromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-Homologation of n-alkanes on metal films.A novel aspect of metal-carbene chemistry, 345-56Investigation into the existence of edgeface coagulated structures in sodian montmorillonite suspensionsZeolite RHO. Part 2. Cation exchange equilibriums and kinetics, 1038-51Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Interaction of boric acid and borates with carbohydrates and related substances, 199 1-2002Thermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Capillary phenomena. Part 10. Behavior of grooved rods at fluid/fluid interfaces, 520-7Capillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofEffect of different cations on the N-CO rotational barrier of N,N-dimethylacetamide.VariableIonic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phaseDynamic adsorption studies on nickel-based methanation catalysts using the continuous flow method,Titanium dioxide-electrolyte interface. Part 1. Gas adsorption and tritium exchange studies, 1-8Titanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Raman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394-402Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-8 1Zeolite sorbents. Modification by impregnation with salts, 180-95Investigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsIonic viscosity B coefficients in dimethyl sulfoxide at 25, 35 and 45"C, 637-47Carbon-13 nuclear magnetic resonance studies of the binding of alkali and alkaline earth metal salts toSalting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Thermodynamic properties of polyelectrolyte solutions.Part 2. Influence of the polyelectrolyte chargeDetermination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Small angle neutron scattering from dilute aqueous dispersions of clay, 314-21(CoGaxAlz-x04) spinel solid solutions, 2448-56REFORMINGREFRACTIVERELAXATIONsilica, 1455-65RESONANCEexchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34RHENIUMRHEOL225-35RHORHODIUMRIBOSERINGRODinfinite extent meeting solids in a gravitational field, 1419-32temperature proton magnetic resonance study, 1 13 1-7ROTATIONRUBIDIUMRUTHENIUMin NaY zeolite, 403-16,2 PLATES2237-50RUTILESALT225-35amides, 1008-1 31062-74density, 1790-800SALTING1062-74SCATTERINJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 57SCATTERING(contd)SCAVENGINGSEAWATEREffect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inSpectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65The Tammann-Tait-Gibson model.Application to the heat capacities of aqueous electrolyte solutions,Secondary ion mass spectra of some simple organic molecules, 549-59Diffusion in organic liquids. Part 1. Appraisal of a gel sectioning technique and its application to self-Seeded emulsion polymerization of styrene, 132343Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Molybdenum-carbon catalysts for reforming reactions, 18 1 1-20Catalytic conversion of alcohols. Part 16. Attempt to correlate the ESCA oxygen 1s binding energy withPressure and temperature dependence of the self-diffusion coefficient of water and oxygen- 1 8 water,Self-diffusion of n-paraffins in NaX zeolite, 717-37Diffusion in organic liquids.Part 1. Appraisal of a gel sectioning technique and its application to self-diffusion in benzene and cyclohexane, 1021-9Diffusion in organic liquids. Part 2. Isotope-mass effects in self-diffusion in benzene and cyclohexane,1030-7Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofDielectric and electrical properties of hydrated bovine serum albumin, 42634Capillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofInvestigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsStudy of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofStudy of molecular sieve carbons.Part 2. Estimation of cross-sectional diameters of nonsphericalMolecular sieving range of pore diameters of adsorbents, 2507-9Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Primary processes in the low-pressure pyrolysis of methylsilane, 1 520-5Cracking of (5-W)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-91Extended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-61Gas-chromatographic studies of hydrocarbon hydrogenolysis on a nickel-silica catalyst, 683-700Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-81Interaction of water with some silicas, 885-8Study of the partial oxidation of propene by oxygen and nitrous oxide over fixed molybdenum catalysts.Infrared study of the adsorption of amines on silica immersed in carbon tetrachloride, 1 158-65Pulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilInfrared study of silica immersed in 2,2,4trimethylpentane + toluene + propionitrile mixtures, 1466-75Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 1476-89Evidence for modification of nickel oxide by silica.Infrared, electron microscope, and dissolution rateJoint studies by x-ray photoelectron spectroscopy and analytical electron microscopy of the dispersion ofSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites.Part 1. Benzene adsorptionPhysico-chemical characterization of impregnated and ion-exchanged silica-supported nickel oxide,aqueous solution, 21 87-93120C18SECONDARYSECTIONINGdiffusion in benzene and cyclohexane, 1021-9SEEDSELECTIVITYthe selectivity, 1917-22SELF377-85SEMICONDambient gas, 2194-205SERUMSHAPEinfinite extent meeting solids in a gravitational field, 1419-32225-35SHEARSIEVEmolecular sieving, 2457-7 1, 1 PLATEmolecules, 2472-85SILANESILICAEssential factors for catalysis and reaction mechanisms, 939-5 1silica, 1455-65studies, 1510-19,2 PLATESnickel oxide supported on silica and silica-aluminas, 1766-72on supports, 1942-522128-41,l PLAT58 J.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980)SILICA(contd)SILICONInfrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaKinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofimmersed in carbon tetrachloride, 2 142-51iodine, 272-9Interaction of oxygen with evaporated silicon films. An infrared study, 630-6S I LOXAN ESurface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofPulsed nuclear magnetic resonance studies of the protons of hexamethyldisiloxane adsorbed on aerosilpolystyrene and poly(dimethy1 siloxane), 1263-74silica. 1455-65SILOXENEFree radical mechanism in olefin isomerization. Isomerization of (Z)-but-2-ene and (Z)-[ 1,2-2Hzlethylene over siloxene, 435-41SILVERSolvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems..Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Structural analysis of molten silver sulfate, 1185-95Ionic liquid mixtures. A modified quasi-lattice theory, 2296309Limiting single-ion molar volumes. Intrinsic volume as a function of the solvent parameters, 2259-84Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phaseConstraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Tarnishing kinetics of powders with lognormal particle size distributions, 2229-36New Zealand allophanes: a structural study, 2542-51Radiation and electron spin resonance study, 244-551062-74SINGLESIZEin NaY zeolite, 403-16,2 PLATESSLOPEEvaluation of DebyeHueckel limiting siopes for water between 0 and 150", 191 1-16SMALLDiffusion in 4A zeolite.Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Improved representation of velocity correlations in aqueous electrolyte solutions, 135-5 1Investigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsPrecise conductimetric studies on aqueous solutions of 2:2 electrolytes. Part 2.Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phasein NaY zeolite, 403-16,2 PLATESNumerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47Aqueous solutions containing amino acids and peptides.Part 10. Enthalpy of interaction of glycine withsome alkali metal chlorides at 298.15 K, 906-1 4Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 161 7-28Effect of sodium on the cobalt-molybdenum-y-alumina system. Part I . Influence of sodium content onthe state of dispersion and on the nature of the cobalt supported on y-alumina, 1677-88Aggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneosmometry, 2035-42Effect of sodium on the cobalt-molvbdenumh-alumina svstem.Part 2. Influence of sodium content andSODIUM225-35preparation methods on the statLof dispersion and natire of molybdenum supported on y-alumina,2052-64,l PLATEEnthalpy of dilution and enthalpy of mixing of sodium carboxymethylcellulose with sodium chloride,Deviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andEffect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules in2080-3lithium titanate-sodium titanate, 21 59-69aqueous solution, 2 187-9J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 59SOLSmall angle neutron scattering from dilute aqueous dispersions of clay, 3 14-21SOLIDCapillary phenomena. Part 1 1. Approximate treatment of the shape and properties of fluid interfaces ofSolid-solid phase transitions in azoxy compounds, 1986-90Deviations from Vegard's law in oxide solid solutions.The systems lithium titanate-magnesia andDistribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateTitanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Solution of hydrogen in nonstoichiometric phosphorus-deficient 3: 1 palladium-phosphorus compoundsAdsorption maxima from solutions of ionic surfactants. A thermodynamic analysis, 386-93Numerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Nucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Freezing temperatures of aqueous solutions containing formamide, acetamide, propionamide and N,N-dimethylformamide. Free energy of interaction between the carbonylimino and methylene groups indilute aqueous solutions, 901-5Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-dimethylacetamide + water mixtures at 35", 1409-18Ionic specific adsorption at the metal-solution interface, 1633-9Calorimetric determination of solution enthalpies of liquids with a small mutual solubility at 298.15 K,Thermodynamic properties of polyelectrolyte solutions.Part 2. Influence of the polyelectrolyte chargeReactions of aliphatic free radicals with copper cations in aqueous solution. Part 2. Reactions with cupricReactions of aliphatic free radicals with copper cations in aqueous solutions. Part 3. Reactions withIonic limiting partial molal volumes in various solvents, 1887-904Thermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneDeviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andProperties of the borate ion in dilute aqueous solutions, 2179-86Limiting single-ion molar volumes.Intrinsic volume as a function of the solvent parameters, 2259-84Thermodynamic study of disorder in lithium bromide monohydrate, 2362-73Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateElectrolyte diffusion at very low concentrations in ionized water, 2552-7Thermodynamics of micellization and solubilization in the system water + sodium n-octanoate + n-pentanol at 25°C. Part 1. Partial molar enthalpies, 473-88Constraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Some reactions at a mercury(I1) sulfide photoanode, 2587-603Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingEvaluation of Debye-Hueckel limiting slopes for water between 0 and 150", 191 1-16infinite extent meeting solids in a gravitational field, 1419-32lithium titanate-sodium titanate, 21 59-69(C0Ga,A1~-~04) spinel solid solutions, 2448-56SOLN196-2081660-2density, 1790-800ions: a pulse radiolysis study, 1825-37cuprous ions: a pulse radiolysis study, 183848mixtures, 2 152-8lithium titanate-sodium titanate, 2 159-69(C0Ga,A12-~04) spinel solid solutions, 2448-56SOLUBILIZATIONSOLUTEupper consolute temperatures, 362-7SOLVATEInfrared study of the solvation of halide ions by water and N-methylacetamide, 225 1-8SOLVATIONSolvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Radiation and electron spin resonance study, 244-55Thermodynamic functions for the system ethanol + p-xylene from vapor pressures, enthalpies of mixingand volume of mixing and their interpretation in terms of association, 53748Nucleophilic substitution in binary mixed solvents.Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Calculations on ionic solvation. Part 4. Further calculations in solvation of gaseous univalent ions usingEffect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-741062-74one-layer and two-layer continuum models, 12 19-3 60 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)SOLVATION(contd)SOLVENTInfrared study of the solvation of halide ions by water and N-methylacetamide, 2251-8Effect of solvents on dipole moment of merocyanine, 43-8Inorganic photophysics in solution. Part 4. Deactivation mechanisms of the 2Eg state of chromium(II1)complexes from lifetime studies, 162-73Spectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Infinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingupper consolute temperatures, 362-7Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24New method of separationof the viscosity B-coefficient of the Jones-Dole equation into ioniccontributions for nonaqueous electrolyte solutions, 1275-86Calorimetric determination of solution enthalpies of liquids with a small mutual solubility at 298.15 K,1660-2Ionic limiting partial molal volumes in various solvents, 1887-904Solubility of synthetic calcium hydroxyapatites, 209-19Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Diffusion in 4A zeolite.Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Zeolite sorbents. Modification by impregnation with salts, 180-95Sorption kinetics of n-hexane on MgA zeolites of different crystal sizes.Study of the rate-limitingSorption in partially hydrated NaA and CaA zeolites, 1166-73Hydrogen sorption by molybdenum sulfide catalysts, 1585-98Ionic specific adsorption at the metal-solution interface, 1633-9Densities of binary liquid mixtures near their consolute points, 2043-5 1Spectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Raman spectra of indium mono-, di-, and triiodides. Correlation between structure and thermodynamicExtended x-ray absorption fine structure studies of highly dispersed platinum catalysts, 357-6 1Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Secondary ion mass spectra of some simple organic molecules, 549-59State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossHydrogen sorption by molybdenum sulfide catalysts, 1585-98Luminescence of porphyrins and metalloporphyrins.Part 1 . Zinc(II), nickel(II), and manganese(I1)Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumAssignment of transient species observed on laser flash photolysis of pbenzoquinone and methylated p-Complexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30New Zealand allophanes: a structural study, 2542-51Effect of sodium on the cobalt-molybdenum-7-alumina system. Part 1. Influence of sodium content onStudies of hydrogen spillover.Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Electron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisLuminescence of porphyrins and metalloporphyrins. Part 1 . Zinc(II), nickel(II), and manganese(I1)Distribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateStability of parameter estimates made using three- and four-parameter extended Arrhenius and Van’tSurface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofSOLYSORPTIONtransport mechanism, 597-6 15,2 PLATESSPECIFICSPECTRAproperties of fused InxIl-x mixtures, 29 1-301spectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30porphyrins, 1978-85oxide, 233-6benzoquinones in aqueous solution, 2432-6SPECTROSCOPYthe state of dispersion and on the nature of the cobalt supported on ?-alumina, 1677-88SPILLOVERSPINof aqueous solutions, 648-53porphyrins, 1978-85(CoGa,A12-,0~) spinel solid solutions, 2448-56Hoff equations, 21 24-7polystyrene and poly(dimethy1 siloxane), 1263-74SPINELSTABILITYSTABILIZATIOJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 61STATEInorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedstate absorption and emission spectra, kinetics and energetics, 797-803Chlorine kinetic isotope effects. Application of the transition state model to thermolysis of secondaryand tertiary alkyl chlorides, 838-45Triplet states of porphyrin esters, 852-9Moderated copolymerization.Part 4. Penultimate unit effect in chain transfer: system styrene/methylmethacrylate/ 1-butanethiol, 107-1 1Moderated copolymerization. Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons. 112-17STERICSTIBINEComDlex formation between iodine and trbhenvlstibine oxide. 1689-93 L d STOP~EDExtraction of rate constant distributions from heterogeneous chemical kinetics, 2065-79Investigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsApparent molal volumes of some highly charged electrolytes in water, 251&18Moderated copolymerization.Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylacrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Seeded emulsion polymerization of styrene, 1 323-43Relaxation studies of the seeded emulsion polymerization of styrene initiated by y-radiolysis, 1344-55Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylModerated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylModerated copolymerization.Part 5. Penultimate unit effect in chain transfer. Systems styrene/methylSTRESS225-3 5STRONTIUMSTYRENEacetate, 1857-67, 1 PLATEmethacrylate/ 1-butanethiol, 107-1 1acrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17mixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24tetrachloride, 302-13STYRYLSUBSTITUTIONNucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in theInfrared study of the adsorption of carboxylic acids on hematite and goethite immersed in carbonPhotochemistry of anhydrides. Part 5. Photolysis of perfluorosuccinic anhydride, 503-1 1Zeolite sorbents.Modification by impregnation with salts, 180-95Precise conductimetric studies on aqueous solutions of 2:2 electrolytes. Part 2. Analysis of data formagnesium sulfate in terms of new equations from Fuoss and from Lee and Wheaton, 368-76Numerical computation of bulk ion concentrations in micellar solutions of sodium dodecylsulfate, 446-7Determination by pulse radiolysis of the distribution of solubilizates between micellar and nonmicellarphases. Naphthalene and its reduced free radical in aqueous sodium dodecyl sulfate solutions, 528-36Interaction between lysozyme and n-alkyl sulfates in aqueous solution, 654-64Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Structural analysis of molten silver sulfate, 1185-95Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 1617-28Aggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneHydrodesulfurization of ethanethiol and related reactions over cobalt monoxide-molybdenum trioxide-Hydrogen sorption by molybdenum sulfide catalysts, 1585-98Some reactions at a mercury(I1) sulfide photoanode, 2587-603Infrared investigation of ionic hydration in ion-exchange membranes.Part 1. Alkaline salts of graftedpolystyrene sulfonic acid membranes, 2558-74, 1 PLATEEffects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption andSUCCINATESUCCINICSULFATE1062-74osmometry, 2035-42alumina and molybdenum disulfide catalysts, 1366-79SULFIDESULFONICSULFU62 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)SULFUR(contd)decomposition of nitric oxide, 11 16-21State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30Isomerization of cis-but-2-ene enhanced by sulfur dioxide adsorbed over decationated-Y and NaYzeolites, 1196-205Electron spin resonance investigation of the persistent free radicals formed from sulfur-nitrogencompounds and olefins, 149&509Study of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofmolecular sieving, 2457-7 1, 1 PLATEGenesis, nature and dispersion of active phase in sulfided cobalt-molybdenumly-alumina hydrodesulfur-ization catalysts. Investigation by analytical electron microscopy and x-ray photoelectron spectroscop-SULFU RIZATIONy, 988-97,2 PLATESSUPERACIDSUPEROXIDESURFACESuperacidity of modified y-alumina.Structure of active site and catalytic activity, 13 11-22Effect of solvation on the electron spin resonance spectrum of the superoxide ion, 1868-74Titanium dioxide-electrolyte interface. Part 1. Gas adsorption and tritium exchange studies, 1-8Titanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Influence of dipole interactions on surface reactions, 49-59Use of the Gibbs equation to calculate adsorption into monolayer-covered surfaces, 118-25Solubility of synthetic calcium hydroxyapatites, 209-1 9Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Adsorption maxima from solutions of ionic surfactants.A thermodynamic analysis, 38693Wall effects in measurement of surface tension using a vertical cylinder. Part 1. Theory, 457-66Wall effects in measurement of surface tension using a vertical cylinder. Part 2. Experimental, 467-72Investigation of the self-association of an amphiphilic drug in aqueous solution, 570-7Implications of elastic deformation on the direct measurement of surface forces, 963-78Surface state and catalytic activity and selectivity of nickel catalysts in hydrogenation reactions. Part 2.Surface characterization of Raney nickel and Urushibara nickel catalysts by x-ray photoelectronspectroscopy, 998-1 007Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption anddecomposition of nitric oxide, 11 16-21Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofpolystyrene and poly(dimethy1 siloxane), 1263-74Surface composition of palladium-gold alloys, 1388-90Characterization of the basicity of oxides through the infrared study of pyrrole adsorption, 147689Surface composition and catalytic activity of chromia-alumina catalysts, 2096101Spectroscopic study of anatase properties. Part 3.Surface acidity, 2102-1 3Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofNew Zealand allophanes: a structural study, 2542-5 1Analysis of electrical double-layer measurements, 2575-86Use of the Gibbs equation to calculate adsorption into monolayer-covered surfaces, 1 18-25Adsorption maxima from solutions of ionic surfactants.A thermodynamic analysis, 386-93Interaction between lysozyme and n-alkyl sulfates in aqueous solution, 654-64Functional micellar catalysis. Part 3. Quantitative analysis of the catalytic effects due to functionalInvestigation into the existence of edge-face coagulated structures in sodian montmorillonite suspensionsSolubility of synthetic calcium hydroxyapatites, 209-1 9Structures of tin oxide-antimony oxide catalysts, 1 174-82,2 PLATESGlass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 161 7-28Deviations from Vegard’s law in oxide solid solutions. The systems lithium titanate-magnesia andElectron transfer at alumina surfaces. Part 6.Redox properties of fluorided aluminas, 202634Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofInfrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of grafteddetermined by neutron diffraction, 2 3 H 3ambient gas, 2 194-205SURFACTANTmicelles and comicelles, 1301-10SUSPENSION225-35SYSTEMlithium titanate-sodium titanate, 21 59-69TCNETCNQambient gas, 2194-205polystyrene sulfonic acid membranes, 2558-74, 1 PLATETEFLOJ.C.S. FARADAY I SUBJECT INDEX VOL.76 (1980) 63TEMPInfinite dilution liquid-gas partition coefficients of some volatile solutes with binary solvents exhibitingTemperature-dependent hyperfine coupling constants in electron spin resonance. Part 6. Planar andWall effects in measurement of surface tension using a vertical cylinder. Part 1. Theory, 457-66Wall effects in measurement of surface tension using a vertical cylinder. Part 2. Experimental, 467-72Investigation of the self-association of an amphiphilic drug in aqueous solution, 570-7Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylIonic limiting partial molal volumes in various solvents, 1887-904Diffusion in n-alkylbenzenes.Diffusion of 1,1,2,2-tetrabromoethane in a homologous series of n-Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Thermal unimolecular decomposition of 1,1,2,2-tetrafluorocyclobutane, 322-3 1Reactions of ethyl radicals with oxygen over the temperature range 400-54W, 2374-82Reactions of ethyl radicals with oxygen over the temperature range 400-540", 2374-82Use of the Gibbs equation to calculate adsorption into monolayer-covered surfaces, 118-25Wall effects in measurement of surface tension using a vertical cylinder. Part 1. Theory, 457-66Ionic specific adsorption at the metal-solution interface, 1633-9Ionic liquid mixtures. A modified quasi-lattice theory, 2296-309Enthalpy of mixing of liquid hydrogen chloride and liquid xenon.Comparison of experiment and theoryDissociation of 1,3-hexadiene and the resonance energy of the pentadienyl radical, 266-7 1Adsorption maxima from solutions of ionic surfactants. A thermodynamic analysis, 386-93Thermodynamic functions for the system ethanol + p-xylene from vapor pressuresJ enthalpies of mixingThermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Zeolite RHO. Part 2. Cation exchange equilibriums and kinetics, 1038-51Calculations on ionic solvation. Part 4. Further calculations in solvation of gaseous univalent ions usingComplex formation between iodine and triphenylstibine oxide, 1689-93Wall-less reactor studies. Part 4. Isobutane pyrolysis, 1694-703Thermodynamic properties of polyelectrolyte solutions.Part 2. Influence of the polyelectrolyte chargeConstraints of molecular packing on the size and stability of microemulsion droplets, 1875-86Thermodynamics of dissociation of DL-malic, maleic, and fumaric acids in water and water + dioxaneIonic liquid mixtures. A modified quasi-lattice theory, 2296-309Surface energetics of the wetting of a hydrophobic powder, 2417-31Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496506Adsorption and activation of ethene by zeolite-H-ZSM-5, 160616Infrared study of silica immersed in 2,2,&trimethylpentane + toluene + propionitrile mixtures, 146675Surface layer thickness in nonaqueous polymer dispersions stabilized by AB block copolymers ofMechanism of the decomposition of methyl thiocyanate, methyl isothiocyanate, and methyl cyanide in aModerated copolymerization.Part 4. Penultimate unit effect in chain transfer: system styrene/methylUse of simple test reactions to characterize the catalytic activity of a commercial cobalt monoxide-Structures of tin oxide-antimony oxide catalysts, 1174-82,2 PLATESupper consolute temperatures, 362-7nonplanar nitroxide radicals, 1296-300TENSIONTERMINATIONmethacrylate/l-butanethiol, 107-1 1TETRAALKY LTETRABROMOETHANEalkylbenzenes, 1433-41TETRAFLUORIDETETRAFLUOROCYCLOBUTANETETRAMETHYLTETRAMETHYLBUTANETHEORYTHERMODN174-9and volume of mixing and their interpretation in terms of association, 537-48one-layer and two-layer continuum models, 1219-3 1density, 1790-800mixtures, 21 52-8THERMOGRAVIMETRYTHERMOSTATICTHICKNESSpolystyrene and poly(dimethy1 siloxane), 1263-74radio-frequency pulse discharge, 1669-76methacrylate/l-butanethiol, 107-1 1molybdenum trioxide-alumina catalyst, 1356-65THIOCYANATETHIOLTHIOPHENETI64 J.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980)TIN(contd)TITAN ATEStructural properties of antimony and tin mixed oxide catalysts, 1652-9Deviations from Vegard’s law in oxide solid solutions. The systems lithium titanate-magnesia andTitanium dioxide-electrolyte interface. Part 2. Surface charge (titration) studies, 9-1 8Photoadsorption and photodesorption of oxygen on highly hydroxylated titania surfaces. Part 3. Role ofRaman spectroscopic study of the polymerization of acetylene on titanium dioxide (rutile), 394-402Differential energies of adsorption of argon and nitrogen on rutile and silica, 774-81Analysis of electrical double-layer measurements, 2575-86Wall effects in measurement of surface tension using a vertical cylinder.Part 2. Experimental, 467-72Infrared study of silica immersed in 2,2,4-trimethylpentane + toluene + propionitrile mixtures, 1466-75Assignment of transient species observed on laser flash photolysis of p-benzoquinone and methylated p-benzoquinones in aqueous solution, 2432-6Isomerization of cis-but-2-ene enhanced by sulfur dioxide adsorbed over decationated-Y and NaYzeolites, 1196-205Moderated copolymerization. Part 4. Penultimate unit effect in chain transfer: system styrene/methylmethacrylate/l-butanethiol, 107-1 1Moderated copolymerization.Part 5. Penultimate unit effect in chain transfer. Systems styrenelmethylacrylate/carbon tetrabromide and styrene/methyl acrylate/ 1-butanethiol and some general considerati-ons, 112-17Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Nucleophilic substitution in binary mixed solvents. Kinetics and transfer enthalpies of anions in themixed solvents methanol + propylene carbonate and methanol + N-methyl-2-pyrrolidone, 8 12-24Thermodynamic studies of cryptand 222 and cryptates in water and methanol, 869-84Relative scale of free energy of transfer of anions from water to 1,24ichloroethane, 1663-8Infrared study of the adsorption of N,N-diethylacetamide and three N,N-diethylaminoketones on silicaBut-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Thermal transformation of goethite into hematite in alkali halide disks, 1442-54Assignment of transient species observed on laser flash photolysis of p-benzoquinone and methylated pEffect of solvents on dipole moment of merocyanine, 43-8Homologation of n-alkanes on metal films.A novel aspect of metal-carbene chemistry, 345-56Effects of wet vibremilling on the polymorphic conversion of aragonite into calcite, 790-6,2 PLATESInorganic photophysics in solution. Part 6. Isotope effects in the nonradiative deactivation of photoexcit-ed uranyl ion in hydroxylic solvents, 804-1 1Chlorine kinetic isotope effects.Application of the transition state model to thermolysis of secondaryand tertiary alkyl chlorides, 83845Triplet states of porphyrin esters, 852-9Luminescence of porphyrins and metalloporphyrins. Part 1. Zinc(II), nickel(II), and manganese(I1)porphyrins, 1978-85Solid-solid phase transitions in azoxy compounds, 198690Quenching of organic singlets and triplets by a complex containing nickel(II), cobalt(II), or manganese(1-Electron donor-acceptor interactions and surface semiconductivity in molecular crystals as a function ofElectron spin resonance detection of spin-trapped radicals formed during the glow-discharge electrolysisKinetics and mechanism of the gas phase thermal decomposition of hexachlorodisilane in the presence ofKinetics of the thermal gas-phase decomposition of 2,3-epoxy-1, 1 ,1-trifluoropropane, 2290-5Investigation of the self-association of an amphiphilic drug in aqueous solution, 570-7lithium titanatesodium titanate, 2 159-69TITAN1 Ahydrogen peroxide in photodesorption of oxygen, 1535-46TITANIUMTITRNTOLUENETOLUQUINONETRANSTRANSFERimmersed in carbon tetrachloride, 2 142-5 1TRANSFORMATIONTRANSIENTbenzoquinones in aqueous solution, 2432-6TRANSITIONI), 2003-10ambient gas, 2194-205of aqueous solutions, 648-53TRICHLORIDEiodine, 272-9TRIFLUOROMETHYLTRIMETAPHANTRAJ.C.S.FARADAY I SUBJECT INDEX VOL. 76 (1980) 65TRIMETHY LTRIMETHYLBUTANETRIMETHYLPHOSPHINETRIPHENY LTRIPHENYLSTIBINETRIPLETComplexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Decomposition of 2,2,3-trimethylbutane in the presence of oxygen, 825-37Complexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Complex formation between iodine and triphenylstibine oxide, 1689-93Complex formation between iodine and triphenylstibine oxide, 1689-93Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Triplet states of porphyrin esters, 852-9Benzophenone triplet properties in acetonitrile and water.Reduction by lactams, 1800-10Tritium recoil ranges and their influence on the helium moderator anomaly, 860-8Diffusion in organic liquids. Part 2. Isotope-mass effects in self-diffusion in benzene and cyclohexane,Tube electrode and electron spin resonance. First-order kinetics, 1391-401Ultraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption andReaction mechanism of ammonia decomposition on tungsten, 280-90Homologation of n-alkanes on metal films.A novel aspect of metal-carbene chemistry, 345-56Field+mission microscopic study of catalytic decomposition of methanol on metal surfaces. Part 1.Chemisorption of carbon monoxide on tungsten( 1 10) and tungsten(320) adsorption, desorption and stateStudies of hydrogen spillover. Part 4. Factors affecting hydrogen spillover and its reversal, 889-900Reactions of methylsilane at the surfaces of nickel, rhodium and tungsten, 979-87Kinetic isotope effect and tunneling in the reaction between 4-nitrophenylnitromethane and pentamethy-Inelastic electron tunneling spectroscopy of selected alcohols and amines on plasma-grown aluminumNITTRITIUM1030-7TUBETUNGSTENdecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( 1 OO), 1 26-34Tungsten, 588-96,2 PLATESinterconversion, 758-73TUNNELINGlguanidine in acetonitrile and toluene, 1905-10oxide, 2335-46Moderated copolymerization. Part 4.Penultimate unit effect in chain transfer: system styrene/methylmet hacry late/ 1 -butane thiol , 1 07- 1 1PSUltraviolet photoelectron spectroscopic and thermal desorption studies of the chemisorption anddecomposition of benzene, cyclohexadiene, cyclohexene, and cyclohexane on tungsten( 1 OO), 126-34Effects of sulfur on a palladium surface on the adsorption of carbon monoxide and the adsorption anddecomposition of nitric oxide, 11 16-21State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30URACILAnalysis of radiolysis products of aqueous uracil + nitrous oxide solutions, 449-56Inorganic photophysics in solution.Part 6. Isotope effects in the nonradiative deactivation of photoexcit-Photochemistry and exciplex of the uranyl ion in aqueous solution, 1093-1 15Surface state and catalytic activity and selectivity of nickel catalysts in hydrogenation reactions.Part 2.Surface characterization of Raney nickel and Urushibara nickel catalysts by x-ray photoelectronspectroscopy, 998-1007URANYLed uranyl ion in hydroxylic solvents, 804-1 1URISHIBARAuvTriplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 417-25Inorganic photophysics in solution. Part 5. Bis(8-hydroxyquinolinato)platinum(II)-absorption, excitedComplex formation between iodine and triphenylstibine oxide, 1689-93Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 1. Benzene adsorptionSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 2. Hydrogenation ofDistribution of cobalt ions among octahedral and tetrahedral sites in cobalt gallate-aluminateComplexation and chemisorption of trimethylphosphine on nickel zeolites, 2519-30state absorption and emission spectra, kinetics and energetics, 797-803on supports, 1942-52adsorbed species, 1953-61(CoGaXA12-,04) spinel solid solutions, 2448-566 J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980)VAPORThermodynamic functions for the system ethanol + p-xylene from vapor pressures, enthalpies of mixingThermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Deviations from Vegard's law in oxide solid solutions. The systems lithium titanate-magnesia andImproved representation of velocity correlations in aqueous electrolyte solutions, 135-51Hydrogen sorption by molybdenum sulfide catalysts, 1585-98Effects of wet vibremilling on the polymorphic conversion of aragonite into calcite, 790-6,2 PLATESThermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Thermal decomposition of cis-2,4-dimethyl-trans-3-vinyloxetan, 1849-56Kinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withAggregation behavior of sodium dodecyl sulfate micelles in aqueous solutions studied by membraneDetermination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Pressure and temperature dependence of the self-diffusion coefficient of water and oxygen-1 8 water,Ionic viscosity B coefficients in dimethyl sulfoxide at 25,35 and 45"C, 637-47New method of separation of the viscosity B-coefficient of the Jones-Dole equation into ioniccontributions for nonaqueous electrolyte solutions, 1275-86Conductance studies in amide + water mixtures. Part 5. Tetraalkylammonium bromides in N,N-dimethylacetamide + water mixtures at 35", 1409-1 8Properties of the borate ion in dilute aqueous solutions, 2179-86Determination of the viscosity of molten potassium nitrate with an oscillating-cup viscometer, 253 1-41Partial molar volumes of organic compounds in water. Part 7. Sodium and hydrochloride salts of u , wThermodynamic functions for the system ethanol + p-xylene from vapor pressures, enthalpies of mixingGlass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 16 1 7-28Ionic limiting partial molal volumes in various solvents, 1887-904Densities of binary liquid mixturps near their consolute points, 2043-51Properties of the borate ion in dilute aqueous solutions, 2179-86Limiting single-ion molar volumes. Intrinsic volume as a function of the solvent parameters, 2259-84Thermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Apparent molal volumes of some highly charged electrolytes in water, 2510-18Quenching of the photoluminescence of porous Vycor glass by oxygen and ammonia, 1014-20Wall effects in measurement of surface tension using a vertical cylinder. Part 2. Experimental, 467-72Zeolite sorbents. Modification by impregnation with salts, 18&95Structure of the lamellar lyotropic liquid crystal, tetramethylammonium perfluorooctanoate + water,Solvation of silver ions in mixed methyl cyanide + water and methyl cyanide + methanol systems.Spectroscopic studies of water-aprotic solvent interactions in the water-rich region, 256-65Small angle neutron scattering from dilute aqueous dispersions of clay, 3 14-21Pressure and temperature dependence of the self-diffusion coefficient of water and oxygen- 1 8 water,Wall effects in measurement of surface tension using a vertical cylinder. Part 2. Experimental, 467-72Thermodynamics of micellization and solubilization in the system water + sodium n-octanoate + n-pentanol at 25°C. Part 1. Partial molar enthalpies, 473-88Studies in ion solvation in nonaqueous solvents and their aqueous mixtures. Part 20. Enthalpies oftransfer of alkali metal halides in the methanol + water systems from enthalpies of dilution, 560-9Thermal desorption study of surface hydroxyls on zinc oxide, 728-45Interaction of water with some silicas, 885-8and volume of mixing and their interpretation in terms of association, 537-48VEGARDlithium titanate-sodium titanate, 21 59-69VELOCITYVIBRATIONVIBROMILLINGVINYLVINYLOXETANEVIOLOGENhematoporphyrin catalyzed by hydrogenase, 2209-1 1osmometry, 2035-42VIRIALVISCOMETERVISCOSITY377-85VOLaminocarboxylic acids, 10 1-6and volume of mixing and their interpretation in terms of association, 537-48VYCORWALLWASHINGWATERdetermined by neutron diffraction, 2 3 H 3Radiation and electron spin resonance study, 244-55377-8J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980) 67WATER(contd)Salting constants of acetonitrile in aqueous electrolyte solutions and preferential solvation phenomenon,Calorimetric determination of solution enthalpies of liquids with a small mutual solubility at 298.15 K,Relative scale of free energy of transfer of anions from water to 1,24ichloroethane, 1663-8Benzophenone triplet properties in acetonitrile and water. Reduction by lactams, 1800-10Ionic limiting partial molal volumes in various solvents, 1887-904Evaluation of DebyeHueckel limiting slopes for water between 0 and 150", 191 1-16Densities of binary liquid mixtures near their consolute points, 2043-51Effect of the nature of the hydrophobic group on the mode of association of amphiphilic molecules inKinetics and mechanism of methyl viologen reduction and hydrogen generation by visible light withSurface energetics of the wetting of a hydrophobic powder, 2417-31Electrolyte diffusion at very low concentrations in ionized water, 2552-7Infrared investigation of ionic hydration in ion-exchange membranes. Part 1. Alkaline salts of graftedpolystyrene sulfonic acid membranes, 2558-74, 1 PLATESome reactions at a mercury(I1) sulfide photoanode, 2587-603Surface energetics of the wetting of a hydrophobic powder, 2417-3 1Exo-electron emission from platinum wires cooling in hydrocarbons and other gases as observed in aCracking of (5-W)-n-nonane with quartz wool, silica-alumina and type Y zeolite, 84-91Field-emission microscopic study of catalytic decomposition of methanol on metal surfaces. Part 1.Formation of wormlike micelles from a polystyrene-polybutadiene-polystyrene block copolymer in ethylEnthalpy of mixing of liquid hydrogen chloride and liquid xenon. Comparison of experiment and theoryStudy of molecular sieve carbons. Part 1. Pore structure, gradual pore opening, and mechanism ofThermodynamics of liquid mixtures of nitrous oxide and xenon, 2496-506Surface state and catalytic activity and selectivity of nickel catalysts in hydrogenation reactions. Part 2.Surface characterization of Raney nickel and Urushibara nickel catalysts by x-ray photoelectronspectroscopy, 998-1007State of sulfur on the palladium surface studied by Auger electron spectroscopy, electron energy lossspectroscopy, ultraviolet photoelectron spectroscopy, and x-ray photoelectron spectroscopy, 1 122-30Thermodynamic functions for the system ethanol + pxylene from vapor pressures, enthalpies of mixingand volume of mixing and their interpretation in terms of association, 53748Assignment of transient species observed on laser flash photolysis of pbenzoquinone and methylated pbenzoquinones in aqueous solution, 2432-6Triplet states of protoporphyrin IX and protoporphyrin IX dimethyl ester, 41 7-25Excitation energy effects on the fluorescence quantum yield in solution. Deactivation pathways forNew Zealand allophanes: a structuial study, 2542-51Diffusion in 4A zeolite. Study of the effect of crystal size, 60-70Diffusion in 5A zeolite. Study of the effect of crystal size, 71-83Cracking of (5-Wkn-nonane with quartz wool, silica-alumina and type Y zeolite, 84-91Zeolite sorbents. Modification by impregnation with salts, 180-95Thermochemistry of hydroxylammonium and hydrazonium zeolites, 332-44Redox behavior of transition metal ions in zeolites. Part 8. Characterization of a ruthenium metal phaseSorption kinetics of n-hexane on MgA zeolites of different crystal sizes. Study of the rate-limitingInteraction of hydroxyl groups in NaHY zeolites with physically adsorbed alkanes, 705-10Self-diffusion of n-paraffins in NaX zeolite, 717-37Reactivity of nitric oxide with nickel ions in A-type zeolite, 952-621062-741660-2aqueous solution, 2 187-93hematoporphyrin catalyzed by hydrogenase, 2209- 1 1WETTINGWIREmodified proportional counter, 1923-41,2 PLATESWOOLWORKTungsten, 588-96,2 PLATESacetate, 1857-67, 1 PLATE174-9molecular sieving, 2457-71, 1 PLATEWORMLIKEXENONX P SXYLENEXYLOQUINONEYIELDaromatic amines, 1576-84ZEALANDZEOLITEin NaY zeolite, 403-1 6,2 PLATEStransport mechanism, 597-61 5,2 PLATE68 J.C.S. FARADAY I SUBJECT INDEX VOL. 76 (1980)ZEOLITE(contd)Zeolite RHO. Part 2. Cation exchange equilibriums and kinetics, 1038-5 1Sorption in partially hydrated NaA and CaA zeolites, 1166-73Isomerization of cis-but-2-ene enhanced by sulfur dioxide adsorbed over decationated-Y and NaYzeolites, 1 196-205But-l-ene transformations on modified forms of a synthetic zeolite of the erionite-offretite type, 1380-7Ferromagnetic resonance study of dispersed nickel particles prepared by reduction of nickel ion-exchanged X zeolites by hydrogen molecules or hydrogen atom beams, 1526-34Comparison of predicted and nuclear magnetic resonance zeolitic diffusion coefficients, 1 562-8Application of absolute rate theory to intracrystalline diffusion in zeolites, 1569-75Adsorption and activation of ethene by zeolite-H-ZSM-5, 1606-16Spectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 1. Benzene adsorptionSpectroscopic studies of benzene hydrogenation on platinum-loaded zeolites. Part 2. Hydrogenation ofTransformations of but- l-ene molecules adsorbed in NaHY zeolites studied by infrared spectroscopy,Complexation and chemisorption of trimethylphosphine on nickel zeolites, 25 19-30Adsorption and decomposition of isopropyl alcohol over zinc oxide. Infrared and kinetic study, 19-29Thermal desorption study of surface hydroxyls on zinc oxide, 728-45Glass formation in the ternary sulfate system, potassium sulfate-sodium sulfate-zinc sulfate, 1617-28Luminescence of porphyrins and metalloporphyrins. Part 1. Zinc(II), nickel(II), and manganese(I1)on supports, 1942-52adsorbed species, 1953612437-47ZINCporphyrins, 1978-8

ISSN:0300-9599    

DOI:10.1039/F198076BA001

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980, 76, 9-18Titanium Dioxide-Electrolyte InterfacePart 2.-Surface Charge (Titration) StudiesBY DAVID E. YATES~ AND THOMAS W. HEALY*Colloid and Surface Chemistry Group, Department of Physical Chemistry,University of Melbourne, Parkville, Victoria 3052, AustraliaReceived 22nd March, 1977Surface charge-pH isotherms for TiOz in K+, Li+, Mg2+ and tetramethylammonium electrolytesolutions are reported for a TiOz colloid sample shown previously to be essentially holocrystallineand non-porous. The charge data are similar to other oxides with the exception of precipitatedsilica. The adsorption sequence obtained is MgZ+ % Li+ > K+ 21 (CH3)4N+.In the present paper we present the potentiometric titration surface charge pro-perties of the TiO,-electrolyte interface for various concentrations of 1 : 1 and 2 : 1electrolytes. The TiO, colloid sample was characterized in detail ; gas adsorptionand tritium exchange studies of the sample showing it to be non-porous are reportedin detail in the previous publication.Electrokinetic potential and coagulationstudies of the same sample have been reported in detail elsewhere.,The surface charge of the oxide-water interface can be determined by measuringthe uptake of the potential-determining ions, H+ and OH-, as a function of the pHof the suspension. The method is a modification of the potentiometric titrationtechnique used successfully by, for example, Lyklema et aL3~ to study the doublelayer at the Agl-solution interface.Potentiometric titrations were first applied to the study of oxide double layers byBolt with a-Fe,O, (haematite) sus-pensions.Their investigations confirmed the potential-determining role of Hf andindicated that the oxide double layers were significantly different from the doublelayers at the Hg and A@-solution interfaces.A different method of measuring the surface charge has been developed byAhmed;’ fresh dry samples of oxide are added to solutions freshly prepared atdifferent pH values. The surface charge is then calculated from the initial pH changesupon immersion. This technique has some advantage in that the oxide is, in principle,not given time to dissolve and so any effects due to soluble species are minimized.Detailed potentiometric titration studies on silica and earlier work by de Bruynand co-workers on a-Fe203 9* lo and later on Ti02 l1 and ZnO 12* l3 showed theuptake of the potential-determining ions occurs in two steps.The first adsorptionstep is rapid and complete within a few minutes, while the second is a slow processwhich may continue for weeks. The occurrence of the slow adsorption step meansthat cro against pH curves determined by potentiometric titration depend to a greateror lesser extent on the titration rate.The fast adsorption process has been attributed to the ionization of the surfacehydroxyl groups, as described by ionization equilibria, which by analogy to mostproton transfer reactions are expected to be practically instantaneous.t Present address : I.C.I. Australia Ltd, Central Research Laboratory, Newson Street, AscotVale, Victoria 3052, Australia.with SiO, sols and by Parks and de Bruyn10 TiO2-ELECTROLYTE INTERFACEIn general the rapid adsorption is the result of the surface charge development,while the slow adsorption reflects slow changes in the P.Z.C.Therefore, rapid acid-base titrations, which suppress the slow adsorption step, provide the most usefulinformation with respect to the oxide-solution interface. The reliability of the acid-base titration technique for determination of o0 values has been substantiated, at leastat low electrolyte concentrations, by direct determination of the concurrent counterion adsorption; results of Hingston et aZ.149 l5 show that the adsorbed counter-ioncharge is, within experimental error, equal and opposite to the surface charge forgoethite and gibbsite suspensions; similar results were obtained by Huang l6 foralumina and, in more detail, by Breeuwsma and Lyklema l7 and Li and de Bruyn l 8for haematite suspensions.calomel supporting suspensionelectrode electrolyte in supportingwith solution electrolytesalt bridgeEXPERIMENTALglasselectrodeMATERIALSThe pure rutile sample had been prepared by hydrolysis of re-distilled titanium tetra-chloride followed by drying and calcining at 150°C.It was cleaned by soxhlet extractionwith water and had a B.E.T. surface area of 19.8 m2 g-l. In the previous paper it wasfully described and shown to be non-porous.All distilled water was triply distilled, the second stage being from alkaline permanganate.All reagents used were A.R.quality unless otherwise stated. The KN03, NaN03, LiN03,Mg(N03)2 and N(CH3)&1 were further purified by recrystallizing from distilled water,after which the KN03 and NaN03, contained in aluminium dishes, were baked overnightat 100°C. The recrystallized LiN03 and N(CH3)&1 were made up as very concentratedsolutions and their concentrations determined by analysis of nitrate and chloride. Thetitrants, 0.10 mol dm-3 HN03 and 0.10 mol dm-3 KOH, were prepared from May andBaker or B.D.H. concentrated standard solutions. Nitrogen gas used to degas solutionsand to exclude C 0 2 was prepurified through concentrated NaOH, HN03 and two aqueousTi02 suspensionsD. E. YATES AND T.W. HEALY 11Following Bates 21 the pH of the suspension was determined relative to the pH of twostandard buffer solutions. The standard buffer solutions used were Merck (Titrisols)pH 4.00 citrate+HCl and pH 9.00 boric acid+ KClf NaOH where the pH is given by-log yk[H+] and y* is the mean ion activity coefficient and [H+] the proton concentration.The electrodes were calibrated in this way before and after each titration.Although at least slight irreversibility between rapid acid and base titrations appearsto be general for metal oxides, repeated titrations on the same suspension were found to bereproducible. Experiments also showed that adsorption isotherms determined on a seriesof identical suspensions were reproducible to better than k0.5 pC cmW2.Outside the pHrange 4-10 the reproducibility decreases due to the relatively large correction for the blank.The absolute accuracy of the titrations depends on the cancellation of the liquid junctionpotentials, which leads to an uncertainty in the pH measurements of w k0.05, and theaccuracy of the surface area determination discussed in the previous paper.lRESULTS AND DISCUSSIONSURFACE CHARGE AGAINST pH ISOTHERMSThe variation of surface charge density of Ti02 as a function of pH for four con-centrations of KN03 is shown in fig. 1. The point of intersection of the o0 againstciI 5\ Yb”2015105051 1 I 1 1 II 5 6 7 8 9 10PHFIG. 1.-Variation of the surface charge density of Ti02 as a function of pH in aqueous solutions ofKN03.A, 2.9 ; x , 0.1 ; 0, 0.01 ; A, 0.001 mol dm-3 KN03.pH curves for different electrolyte concentrations defines the P.Z.C. at pH = 5.8k0.1in KNO3. This value agrees well with the i.e.p. of 5.S5+0.1 for the same sample inKN03 determined by Wiese using microelectrophoresis and coagulation ratetechniques and is well within the range of values previously reported 22 for syntheti12 TiO2-ELECTROLYTE INTERFACEand natural Ti02.* The P.Z.C. also coincides with the inflection points of the lO-l,mol dm-3 curves. The general shape of the curves is typical of thereported ao-pH curves for synthetic oxides other than Si02. The ao-pH curveon 2.9 mol dm-3 KN03 appears to be approaching a maximum in a. at high pH.andPHFIG. 2.-Variation of the surface charge density of TiOz as a function of pH in aqueous solutions ofLiN03.A,A, 1.0; x, 10-1 ; 0, ; 0, mol dm-3.The results for LiN03 axe shown in fig. 2 where a number of different features areobserved. For LiN03 concentrations of 10-1 moldm-3 and lower, the P.Z.C. ispH 5.9k0.1, which is, within experimental error, the same as observed in KN03.However, in 1.0 mol dm-3 LiN03 the P.Z.C. shifts quite significantly towards lowervalues. Furthermore, the go against pH curves are much steeper and reach muchhigher values than were observed in KN03. The difference between the LiN03 andKN03 curves becomes larger with increasing concentration. This is similar to thebehaviour observed by Breeuwsma 1 7 9 2o for a-Fe203 in concentrated LiCl solutions.The titration of the 1.0 mol dm-3 LiN03 +Ti02 suspension also showed greaterhysteresis than the other titrations and when the suspension was equilibrated for* P.z.c.and i.e.p. definitions are as given by Lyklema and Healy (see Disc. Faraday Soc., 1971,52, 318)D. E. YATES AND T. W. HEALY 13several days at pH 4.8, the pH slowly drifted downscale, even though atmosphericCOz was rigorously excluded. Subsequent rapid acid-base titrations showed thatthe oo against pH curve was moved to lower pH values. This behaviour indicatesthat the slow adsorption step, discussed above, is not completely suppressed by therapid titration procedure and that slow adsorption of Li+ continues even at pHvalues below 5.0. All these trends indicate that Li+ is much more strongly adsorbedthan NO; and K+, i.e., Li+ is specifically adsorbed on TiOz.BCrubC and de Bruyn 23also observed high values of cro in the presence of 10-1 moldm-3 Li+, but did notreport any results for 1.0 mol dm-3 LiN03 or any shift in the P.Z.C.PHFIG. 3.-Variation of the surface charge density of TiOz as a function of pH in aqueous solutions of(CH&NCl. Scales are larger than those in fig. 4 ad 5. 77, 10-1 ; x , ; 0, rnol dm-3.and 10-1 mol dm-3 NaN03 again gave aP.Z.C. of pH 5.9 40.1 in good agreement with the P.Z.C. in KN03 and in 10-3-10-1 moldm-3 LiN03. The surface charge densities indicated that the magnitude of Na+adsorption was closer to the extent of Li+ adsorption than to K+ adsorption.The results for (CH3)4NCl are shown in fig. 3, where again the P.Z.C.ofpH = 6.0+0.1 agrees with the P.Z.C. determined in the other 1 : 1 electrolytes. Thecurves are qualitatively similar to the curves obtained in the other electrolytes butdiffer in that, for mol dm-3 (CH3)4NCl, go for the negative branch is higher thanin the presence of K+ or Lif and then does not increase as much with increasing con-centration. In the only other study of oxide surfaces in the presence of tetra-alkylammonium ions, Tadros and Lyklema 24 observed that oo for porous SiOz in(C2H.J4NC1 solutions was almost independent of concentration. This is a morepronounced version of the trend in the oo against (CH3)4NC1 concentration behaviourobserved here. In 0.1 mol dm-3 (CH3)4NCl, go = oo in 0.1 mol dm-3 KN03 and4 go in 0.1 niol dm-3 LiN03 or NaN03.In order to try and push the surface charge to higher values, a titration wascarried out in Mg(NO& solutions.The results are shown in fig. 4. The oo againstpH curves are much steeper and reach higher negative surface charges than wereobserved in equivalent concentrations of the 1 : 1 electrolytes. The P.Z.C. determinedA preliminary titration i14 TiO2-ELECTROLYTE INTERFACEfrom the intersection point of the and moldm-3 curves was againpH 5.8 k0.1. However, the P.Z.C. shifted with increasing Mg(N03)2 concentrationand the intersection point of the and 10-1 mol dm-3 curves was at pH 5.6A0.1.A further titration in 1.0 mol dm-3 Mg(N03), showed an inflection point and hencea probable P.Z.C. at pH 5. The maximum oo observed in 1.0 mol dm-3 Mg(N03)2was 73 pC cm-2 at pH 8.3 but the hydrolysis of aqueous Mg2+ made this titrationunreliable at pH values above 8.The shift in the P.Z.C. and the high surface chargesobserved both indicate that Mg2+ is specifically adsorbed and more strongly so thanLi+, which did not shift the P.Z.C. until the concentration was > 10-1 mol dm-3.Breeuwsma l7. l9 also found that Mg2+ shifted the P.Z.C. of a-Fe,03, although theshift was larger and occurred at lower concentrations [< mol dm-3 Mg(N03),]than the shift observed here on Ti02.In general the shape of the go against pH curves for Mg(N03)2 is similar to theshape in the 1 : 1 electrolytes except that the change in pH necessary to keep thesurface charge constant if the activity of the electrolyte is increased by tenfold, i.e.,the Esin-Markov ~oefficient,~~ is smaller in Mg(N03)2 than in the 1 : 1 electrolytes.This is in good agreement with the theoretical Esin-Makov coefficients calculatedby Lyk1e1n.a.~~I 1 I 1 1 I5 6 7 8 9PHFIG.4.-Variation of the surface charge density of TiOa as a function of pH in aqueous solutions ofMg(NO&. V, 10-1 ; A, ; 0, mol dnr3D. E. YATES AND T. W. HEALY 15Comparison of the cr, against pH curves described here with reported results forboth natural 26 and synthetic uncalcined rutile 2 3 9 27 reveal good qualitative agree-ment, although the magnitude of the cr, values found in the present study appears tobe slightly lower. A precise compaxison is not possible because different workershave used different electrolytes.The slightly lower cr, values may be a result of thecalcining of the present sample. Further comparison of the present cro against pHcurves with those of other oxides shows that the present sample also exhibits similardouble layer properties to most other metal oxides, in particular to a-Fe203,178 2oy 28* 29E - F ~ O O H , ~ ~ ZnO 12* l3 and Al2O3.l69 30 As with the other oxides, the cro valuesand differential capacities at high electrolyte concentrations are considerably greater(w 3-5 times) than the corresponding values for the classical mercury and AgIinterfaces. Of course, these high values were the reason for the proposal 24* 31 ofthe gel layer theory of oxide-water interfaces in which it is proposed that the surfacecharge and part of the counter-charge can be accommodated behind the surfaceproper.However, in this case our extensive studies of the nature of the Ti02surface revealed no evidence of either physical porosity or the presence of gel layersat the surface. It might be argued that a gel layer does exist while the oxide is insolution but collapses on out-gassing to form a non-porous crystalline surface so thatour surface characterization would not have revealed it. This is unlikely for tworeasons; firstly, the out-gassing was carried out under very mild conditions (i.e.,room temperature) and secondly, the gel layer must reform unexpectedly rapidlywhen wetted with aqueous solutions. This follows because Ahmed’s ’* 26 studiesshow clearly that the high surface charges are developed as soon as dry Ti02 and otheroxides axe wetted with electrolyte solutions. In view of the slow rates of crystal-lization and dissolution of most metal oxides, it is unlikely that a gel layer on rutilewould crystallize so readily or reform so rapidly.With regard to the maximum possible surface charge for Ti02, it is interesting tolook also at the work of Boehm 32 and Schindler and Gamsjager 3 3 on a pyrogenicsample (Degussa P25).These workers obtained maximum charges of w -65 and- 48 pC cm-2 in NaOH and NaC10, solutions at high pH compared to our maximummeasured value of -73 pC cm-2 in 1 mol dm-3 Mg(N03)2. However, none of thesevalues is expected to correspond to full ionization of the surface groups, as no definiteplateau has ever been observed on go against pH isotherms.In fact, in om previouspaper it was shown that the rutile surface carries z 6 OH groups per nm2 plus3 coordinated H20 molecules per nm2, which gives a maximum surface charge ofw - 190 pC cm-2 if all these groups were fully dissociated. Therefore the maximumobserved cr, values are all considerably less than the maximum possible charge, whichwas to be expected if the surface consists of exposed impenetrable crystal planes.The gel layer model of oxides would have allowed much greater cr, values.Therefore the present rutile sample exhibits typical oxide surface charges (i.e.,high), even though there is no independent evidence of any surface porosity. Henceit appears that while surface porosity to ions may, in some cases,** 24 contribute tothe high surface charge densities observed for oxides, it cannot be the general explana-tion.The present results have been used in two separate theoretical papers 3 4 y 35where site dissociation models of the e.d.1. of oxides have been used to analyse thedata.ION ADSORPTION SEQUENCESFinally, it is necessary to consider the important experimental approach of study-ing “ ion adsorption ” or ‘‘ ion specificity ” sequences.This approach was not use16 TiO,-E LE CTROL Y TE I N T ERF A CEextensively in the present study; only a brief comment is needed. The oo againstpH curves for 0.10 mol dm-2 K+, Li+ and Mg2+ nitrates are compared in fig. 5where it is clearly seen that the order of adsorption on the negative side iswhich reveals the importance of both the chemical nature and charge of the cation.It is also apparent from the agreement of the positive oo values in fig.5 that, withinexperimental error, there is no significant co-ion effect.P HFIG. 5-Variation of the surface charge density of TiOz as a function of pH in aqueous solutions of0.10 mol dm-3 K+(A), Li+(O) and Mg2+(V) nitrates.For oxides the order in the specificity of adsorption of ions depends on the particu-lar oxide. For example, the adsorption of alkali-metal ions, given by the presentand other studies on Ti02 23 and a-Fe203,17* 2 1 ~ 2 8 increases in the orderLi+ > Na+ > K+ > Cs+, but on Si02 surfaces 24p 36 the sequence is reversed. Theorder observed for both mercury and AgI interfaces is the same as observed onSO2, i.e., Cs+ > Li+.The observed adsorption sequence of tht; halide ions onTiOz 24 and ZnO 12* l3 is C1- > Br- > I-, which is the reverse order of that foundon mercury. The most thorough study of ion specificity in 1 : 1 electrolytes has beenmade on a-Fe203 sols by Dumont and Watillon 37 using a coagulation technique.Where comparison is possible, their stability sequences are in agreement with corD . E. YATES AND T . W. HEALY 17responding adsorption sequences,17* 9 9 * higher adsorption corresponding to lowerstability. Dumont and Watillon 37 considered that the ion-surface interactionswere governed by Gurney 3 8 type “ structure making ” and “ structure breaking ”properties of the ions and of the surface itself.In solution, ions of like orderingattract, those of opposite ordering repel each other. Therefore their a-Fe203 and thepresent TiQ, behave as a structure-promoting surface, as “ structure making ” ionssuch as Li+ are adsorbed more strongly than “ structure breakers ”. Surfaces suchas mercury, AgI or SO,, which preferentially adsorb “ structure breaking ” ions likeCs+, act as “ structure breaking ” surfaces. Hence ion-surface interactions areregarded as analogous to bulk electrolyte ion-ion interactions. There are, however,several general hypotheses for explaining ion sequences on various surfaces, for theproblem is a difficult one and more fundamental knowledge of the relative and absoluterole of factors such as electrostatic attraction, specificity of ion interaction, ionhydration and water structure is required.CONCLUSIONSIn summary, the go against pH curves presented here clearly show that thepresent sample of TiO, is characteristic of TiO, samples studied by other workersand exhibits similar double layer properties to most other metal oxides, in particularto a-Fe2O3,l79 19* 2 8 * 29 WF~OOH,,~ ZnO l2.l3 and Al2O3.l6’ 30 As with theseother oxides, the go values at high electrolyte cuncentrations are considerably greater(= 3-5 times) than the cr0 values for mercury and AgI interfaces at correspondingpotentials and conditions. Nevertheless, although no limiting value of go has beenobserved, all the experimental go values are considerably lower than the possiblesurface charge produced by full dissociation of all the surface groups ; in particular,the values observed for go and the differential capacity were much larger than thecorresponding values for the classical mercury and AgI interfaces.Thus highsurface charges occur for rutile-aqueous electrolyte interfaces even when there is noindependent evidence of either physical porosity or the presence of gel layers at thesurface.It was not possible to completely exclude the presence of a gel layer when therutile is in solution. However, if such a gel layer is present in solution then it mustcollapse to form a non-porous crystalline surface under conditions as mild as roomtemperature outgassing. Furthermore, if a gel layer is responsible for the highsurface charges, it must reform rapidly when wetted with aqueous solutions. This isbecause Ahmed’s ‘9 26 studies clearly show that the high surface charges are developedas soon as dry TiO, and other oxides are wetted with electrolyte solutions.In viewof the slow rates of crystallization and dissolution of most metal oxides, it is unlikelythat a gel layer on rutile would crystallize so readily or re-form so rapidly. A sitedissociation model 349 35 appears more useful at present.This work was supported by the Australian Research Grants Committee.D. E. Y . acknowledges the award of a Commonwealth Postgraduate Research Award.D. E. Yates, R. 0. James and T. W. Healy, J.G.S. Furuduy I, 1980, 76, 1.G. R. Wiese and T. W.Healy, J. Colloid Interface Sci., 1975, 51, 434.M. J. Sparnaay, The Electrical Double Layer (Pergamon Press, New York, 1972).J. Lyklema and J. Th. G. Overbeek, J. Colloid Sci., 1961, 16, 595.G. H. Bolt, J. Phys. Chem., 1957, 61, 1166.G. A. Parks and P. L. de Bruyn, J. Phys. Chem., 1962,66,96718 TiO,-E LE CTRO LY TE INTERFACE' S. M. Ahmed, Oxides and Oxide Films, ed. J. W. Diggle (Marcel Dekker, New York, 1972),vol. 1, chap. 4, p. 230.D. E. Yates and T. W. Healy, J. Colloid Interface Sci., 1976, 35,9.G. Y. Onoda and P. L. de Bruyn, Surface Sci., 1966,4,48.lo Y. G. BCrubC, G. Y. Onoda, Jr. and P. L. de Bruyn, Surface Sci., 1967, 8,448.l 1 Y. G. BCrubC and P. L. de Bruyn, J. Colloid Interface Sci., 1968,27, 305.l2 L. Blok, Ph.D. nesis (State University, Utrecht, 1968).l 3 L. Blok and P.L. de Bruyn, J. Colloid Interface Sci., 1970,32, 518, 527 and 544.l4 F. J. Hingston, R. J. Atkinson, A. M. Posner and J. P. Quirk, 9th Int. Congr. Soil Sci. Trans.,l5 F. J. Hingston, A. M. Posner and J. P. Quirk, J. Soil Sci., 1972, 23, 177.l6 C. P. Huang, Ph.D. Thesis (Harvard University, 1971).l7 A. Breeuwsma and J. Lyklema, Disc. Faraday SOC., 1971, 52, 324.l8 H. C. Li and P. L. de Bruyn, Surface Sci., 1966, 5, 203.l9 D. E. Yates, Ph.D. Thesis (University of Melbourne, Australia, 1974).2o A. Breeuwsma, Thesis (Agricultural University, Wageningen, The Netherlands, 1973).21 R. G. Bates, Determination of pH, Theory and Practice (J. Wiley, New York, 1964).22 G. A. Parks, Chem. Rev., 1965,65, 177.23 Y. G. BCrubC and P. L. de Bruyn, J. Colloid Interface Sci., 1968, 28, 92.24 Th. F. Tadros and J. Lyklema, J. Electroanalyt. Chem., 1968, 17, 267."J. Lyklema, J. Electroanalyt. Chem., 1972, 37, 53.26 S. M. Ahmed and D. Maksimov, J. Colloid Interface Sci., 1969, 29, 97.27 H. J. Wright, Ph.D. Thesis (University of Sydney, 1972).28 A. Breeuwsma and J. Lyklema, J. Colloid Interface Sci., 1973,43,437.29 R. J. Atkinson, A. M. Posner and J. P. Quirk, J. Phys. Chem., 1967,71, 550.30 C. P. Huang and W. Stumm, J. Colloid hterface Sci., 1973,43,409.31 J. Lyklema, J. Electroanalyt. Chem., 1968, 18, 341.32 H. P. Boehm, Adv. Catalysis, 1966, 16, 249 ; Angew. Chem. Int. Edn, 1966,5, 541 ; Disc.Faruday SOC., 1971,52,264. ; M . Herrmann and H. P. Boehm, 2. anorg. Chem., 1969,368,73.33 P. W. Schindler and H. Gamsjager, Disc. Faraday SOC., 1971,52,286 ; Kolloid-Z., 1972, 250,759.34 J. A. Davis, R. 0. James and J. 0. Leckie, J. Colloid Interface Sci., 1978, 63,480.35 T. W. Healy and L. R. White, Adv. Colloid Sci., 1978, 9, 303.36 R. P. Abendroth, J. Colloid Interface Sci., 1970, 34, 591.37 F. Dumont and A. Watillon, Disc. Faraday SOC., 1971, 52, 352.38 R. W. Gurney, Ionic Processes in Solution (Dover Publications, New York, 1953).1966, 1, 669.(PAPER 7/502

ISSN:0300-9599    

DOI:10.1039/F19807600009

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980,76, 19-29Adsorption and Decomposition of Isopropyl Alcoholover Zinc OxideInfraed and Kinetic StudyBY OSAMU KOGA, TAKAHARU ONISHI* AND ~ N Z I TAMARUDepartment of Chemistry, Faculty of Science,University of Tokyo, Bunkyo-ku, Tokyo 113, JapanReceived 19th December, 1977The adsorption of isopropyl alcohol and acetone on zinc oxide was studied by an infraredtechnique which revealed that isopropyl alcohol is dissociatively adsorbed at room temperature toform zinc alcoholate and hydroxyl group on the surface, while the adsorption of acetone takes placein its enolic form. When adsorbed isopropyl alcohol was heated to 363 K, the zinc alcoholatespecies changed gradually to acetone adsorbed in its enolic form, which further desorbed at highertemperatures as acetone, being replaced by the attacking isopropyl alcohol.The behaviour of the adsorbed species during decomposition of isopropyl alcohol on zinc oxidewas studied in more detail, leading to the overall reaction mechanism described by eqn (V).The dehydrogenation of isopropyl alcohol over metal oxides is both technicallyimportant and is a basic catalytic reaction in view of its selectivity and catalyticactivity.Krylov studied a scheme for dehydrogenation of isopropyl alcohol overzinc oxide, a typical dehydrogenating catalyst. He considered the relation betweenthe activity of various catalysts and their properties and suggested an adsorbedalcohol " dissociated at a-hydrogen " and " enol- or keto-type of acetone " asreaction intermediate, and that the dehydrogenation step from dissociated alcoholto adsorbed acetone was rate-determining.Teichner and coworkers measuredthe pressure increase under various reaction conditions and concluded that the ratedetermining step is the dehydrogenation of adsorbed alcohol to form acetone, amechanism similar to that of Krylov. Both, however, obtained no direct informationabout either the adsorbed species or the reaction sites and assumed some partialequilibrium in their reaction sequences. Desorption of isopropyl alcohol from zincoxide was studied by Kemball and coworkers who reported that even at tempera-tures as high as 573 K some species are not removed from the catalyst surface; inparticular less acetone was desorbed in cornpaxison with hydrogen.In this report the adsorption of isopropyl alcohol and acetone on zinc oxide wasstudied by infrared spectroscopy, and the mechanism of decomposition of isopropylalcohol to produce acetone is elucidated by measuring not only its rate but also theadsorption and kinetic behaviour of adsorbed species during the reaction.EXPERIMENTALZinc oxide (Kadox 25 from New Jersey Zinc Co., surface area 10 m2 g-l) was pressedinto a self-supporting disc ( M 0.2 g), which was placed in an infrared cell and connected toa conventional closed circulating system, as reported previou~ly.~ The catalyst disc wasevacuated N m-2) at 690 K for 2 h and further treated for 2 h at 730 K in 13 kN m-2oxygen being circulated through a trap cooled by liquid nitrogen.120 ADSORPTION OF ISOPROPYL ALCOHOLIsopropyl alcohol and acetone were used after purification by repeated distillation.[2H8]Isopropyl alcohol and [2H6]acetone were obtained from Merck.The infrared spectra of the adsorbed species were measured in the region 4000-900 cm-l .If necessary, the 900-600 cm-I range was also measured by putting almost the same amountof catalyst in the reference beam.The procedure and apparatus employed in measuring the adsorption were similar tothose employed previo~sly.~ Zinc oxide catalyst ( m 3.0 g) for the kinetic study was usedin the form of a disc and treated under the same conditions as for the infrared study.Theadsorption and the rate of decomposition of isopropyl alcohol were measured in a circulatingsystem at 363 K.The amounts of the adsorbed alcohol and acetone were determined by the peak heightof the infrared spectra using the reference cell to compensate gas phase absorptions. Thecalibration curves for adsorbed isopropyl alcohol and acetone shown in fig.1 were deter-mined by measuring the 1129 and 1500 cm-l bands when known amounts of isopropylalcohol and acetone were separately adsorbed.The reactant and product gases were analysed by gas chromatography using a 1 mdioctylsebasate column at room temperature.1.61 . 41 . 21.00 80.60.40.220 40 60amount/pmol g1FIG. 1.-Calibration curve of adsorbed species at room temperature (shaded symbols) and 363 K(open symbols). 0, isopropyl alcohol (IPO), 1129 cm-I; A, A, acetone (En), 1500 cm-l.RESULTS AND DISCUSSIONINFRARED STUDYADSORPTION OF ISOPROPYL ALCOHOLThe infrared spectra of isopropyl alcohol adsorbed on zinc oxide at room tem-perature are shown in fig.2. The amount of saturated adsorption was nearl0. KOGA, T. ONISHI AND K . TAMARU 2160 pmol (g cat)-’. The sharp bands at 3616 and 3665 cm-l, due to the hydroxylgroup on zinc oxide, decreased on alcohol adsorption and a new broad band around3300 em-1 increased.wavenumber /cm-’FIG. 2.-Infrared spectra of adsorbed isopropyl alcohol (IPO). - - -, ZnO background ; -,adsorbed alcohol (IPOH); --- , adsorbed alcohol after exchange with D2 (IPOD) at roomtemperature.TABLE UP O INFRARED BANDS OF ISOPROPYL ALCOHOL, ITS ZINC ALCOHOLATE AND ITS ADSORBEDSPECIES ON ZnOadsor bedalcohol zinc species(liquid) alcoholate (this work) assignment/cm-l /cm-l /crn-l1470 vs1412 m1382 vs1372 vs1342 s1311 vs1162 m1130 vs1450 vs 1458 vs WH3)&CH)1366 vs 1380 vs WH3)1356 vs 1366 vs 6033)1330 s 1338 s wm&OH)1160 m 1159 m skeletal1133 vs 1129 vs skelet a1The hydrogen exchange reaction between adsorbed alcohol and deuterium gas(13 kN m-2) at room temperature was also studied and revealed that only hydrogenin the hydroxyl group of alcohol was exchanged.The broad band of hydroxylgroup around 3300 cm-l was shifted to 2500 cm-l by the exchange reaction, all theother bands staying unchanged (fig. 2).The spectrum in fig. 2 was compared with those of liquid alcohol and zincalcoholate in table 1.The table shows that the band positions are reasonably simila22 ADSORPTION OF ISOPROPYL ALCOHOLto those of alcoholate, which suggests that alcohol is adsorbed dissociatively to formzinc alcoholate and hydroxyl group on the surface, as follows,H H(1)I II IICH3-C-CH3- CH,-C-CH, + HI-0- .ZnO0-Zn-OHADSORPTION OF ACETONE ON ZnOTypical infrared spectra of small amounts of acetone [ZO pmol (g cat)-l] adsorbedon zinc oxide at room temperature are shown in fig. 3. There was no indicationthat the adsorbed acetone desorbed during evacuation at 383 K for a few hours.3600 2800 2000 1700 1500 1300 1100 900 700wavenumber /cm-FIG. 3.-Infrared spectra of adsorbed acetone (En). - - -, ZnO background, nearly the same amountof ZnO in the reference beam ; (a) adsorbed E2Ho]acetone, (b) adsorbed [2Hs]acetone.The spectrum of adsorbed acetone lacks the absorption band characteristic ofC=O stretching of acetone vapour at 1745 cm-l.In addition the following newbands appeaxed in the spectrum of adsorbed acetone; (a) a sharp band for OHgroup at 3360 cm-l with weak absorption of the H-C- group at 3040 cm-l and(b) a strong skeletal vibration band at 1500 cm-5To collect more information on the behaviour of hydrogen in the adsorbedstate, a hydrogen exchange reaction was carried out at room temperature betweendeuterium (13 kN m-2) and acetone [20 pmol (g cat)-l] adsorbed on zinc oxide.The results of the exchange demonstrated that the hydrogen atoms both in thehydroxyl and in the hydrocarbon group were exchanged, resulting finally in thecomplete exchange of all the hydrogen atoms in acetone?As the exchange reaction proceeded, the band around 1500 cm-l shifted graduall0.KOGA, T. ONISHI AND K. TAMARU 23to 1465 cm-l. The amounts of hydrogen and/or deuterium in the hydroxyl groupof the adsorbed species was estimated from their intensity. In fig. 4 the deuteriumcontent in the hydroxyl group of the adsorbed molecule (OD/OH+OD) is plottedagainst the peak position of the adsorbed molecule near 1500cm-l. The skeletalC=C bond shifts linearly with the deuterium content of the hydroxyl group, support-ing the idea that the OH group is directly attached to the C-C bond.0 0.2 0.4 0.6 0.8 1 .OOD/OH+ODFIG. 4.-Band shift of peak at nearly 1500cm-l for En under partial deuteration.OH (OD)represents OH (OD) concentration of En from the infrared absorbance at 3360 cm-l (2510 cm-l).Roginsky and coworkers observed an OH band in the region 3550-3750 c dand two strong bands at 1575 and 1515 cm-l in the range characteristic of the C=Ostretching vibration in the spectra of acetone adsorbed on NiO. They proposed anenolate type adsorption species as follows :CH3\1 CH3COCH3 --+ C=O - - - NiO.NiO".CH H/ \\/IC CC M-C\ /A M--- 11 T-/ \. H H H/ \H(1) (2) (3)which is a hybridized structure of (2) and (3).124 ADSORPTION OF ISOPROPYL ALCOHOLIn table 2 the characteristic infrared bands of acetone adsorbed on zinc oxideare compared with the enol type molecules.This comparison leads to the conclusionthat the adsorbed species on ZnO is an enol type as follows :CH3ICHO H\ / c=cNagai and Miyahara l5 studied the infrared spectra of acetone adsorbed on ZnOand found that the adsorbed acetone species is an enolate.When large amounts of acetone [ > 40 pmol (g cat)-l] were introduced onto zincoxide, the spectrum differed from that of fig. 2, as shown in fig. 5. This spectrum,which has a new peak around 1600 cm-l, is similar to that reported by Nagai et al.It is known that polymerization of acetone takes place on zinc oxide. Accordingly,the spectrum in fig. 5 can be assigned to a polymerized species of acetone such asacetylacxtone.1700 1500 1300 1100wavenumber/cm-lFIG. 5.-Infrared spectra of adsorbed acetone in excess amounts (52 pmol g-l)0.KOGA, T . ONISHI AND K . TAMARU 25TABLE 2.-cHARACTERISTIC BANDS OF ENOL TYPE SPECIES AND ADSORBED ACETONEadsorbed species(RCHZ- (this work)CMeOH)+Br- l4 C3HsC120-Pt l2 CH3COCH3 CD3COCD3 assignment1515 s3300 vs 3360 w 2510 m3020 w 3040 w2960 w 2220 w2930 w2880 w1545 s 1500 vs 1465 vs1435 m 1046 w1362 m 1350 s1301 s1080 w --__-__--.,1050 w ---------.,'::940 w930 w w o w765 vs 793 w752 w-OH(-OD)H-C==-CH3(-CD,)-CH3-CH3 c=c-CH3(-CDs) c-050 100 150 200 250When adsorbed isopropyl alcohol was heated to 363 K, the spectrum of theadsorbed species changed from that in fig. 2 to curve (a) in fig. 3 ; isopropyl alcoholatespecies on ZnO changed to an enol type acetone species at this temperature, indicatingFIG.6.-Reaction between En(a) and hydrogen (18 kNme2) to produce IPO(a) on ZnO at 363 K.reaction time/mi26 ADSORPTION OF ISOPROPYL ALCOHOLthat the first step in the decomposition of isopropyl alcohol is the dissociative adsorp-tion to alcoholate and hydroxyl groups on the surface which react further to enol(a)and hydrogen.When adsorbed acetone, En(a), was heated at 363 K in the presence of 18 kN m-2hydrogen, it was converted into isopropyl alcoholate (IPO) as shown in fig. 6, furthersupporting the reversible process H2 + En(a) + IPO(a) + H(a).(2) (3) (4)reaction timelminFIG. 7.-Decomposition of isopropyl alcohol on ZnO at 363 K. (1) Gas phase was removed by aliquid nitrogen cold trap just after introducing alcohol to the reaction cell.(2) Release of condensedgases from the trap. (3) Reintroduction of isopropyl alcohol. (4) Evacuation of gas phase.-0-, IPA, isopropyl alcohol in gas phase ; -@-, ACT, acetone (g) ; - x -, PP, propylene (g) ;--A-, Hz (8); -0-, IPO, adsorbed isopropyl alcohol (alcoholate); -El-, En, adsorbedacetone (enol).KINETIC STUDY OF DECOMPOSITION OF ISOPROPYL ALCOHOLIsopropyl alcohol decomposes over zinc oxide at 363 K to form mainly acetoneand hydrogen ( M 90 % selectivity) and small amounts of propylene and water (10 %).A typical result of the dynamic study at 363 K is given in fig. 7, where the changes inpartial pressure of the reactants and products and the amounts of each adsorbedspecies are shown. Soon after contact of alcohol with the catalyst, the gas phas0 .KOGA, T. ONISHI AND K. TAMARU 27components other than hydrogen were removed by circulating the reacting gas andcondensing in a liquid nitrogen trap (period 1) ; after 2 h the condensed gases werereleased by removing the liquid nitrogen (period 2).During period 1 , the amounts of species adsorbed during reaction were estimatedfrom i.r. intensities, and by measuring the pressure and composition of the ambientgas and the amount of condensate (determined by gas chromatography at suitabletime intervals) in the trap. The amount of adsorbed alcohol decreased, whilehydrogen in the gas phase and the adsorbed acetone (enol species) increased withtime by almost the same amount. The adsorbed acetone desorbed negligibly asKemball et aL3 observed in the absence of alcohol in the gas phase.- P1 2log ([IPOIIWOl g-'1FIG.8.-Dependence of the initial rate of En formation upon IPO coverages.At the start of period 2, the adsorbed alcohol increased, whereas the adsorbedacetone decreased desorbing into the gas phase by amounts corresponding to therelease of condensed vapours from the trap. The decomposition of alcohol con-tinued subsequently, while adsorbed alcohol and acetone remained almost constant.Thus the following scheme for the overall reaction can be proposed to explain theseresults :IPOH(g) e IPO(a) + H(a)+ H(a) + En(a) -I- H,(g)(1)(2)(3) En(a) + IPOH(g) + IPO(a) + ACT(g)where IPOH(g), IPO(a), En(a) and ACT(g) show gaseous isopropyl alcohol, isopropylalcolate (adsorbed), enol type adsorbate and gaseous acetone, respectively.Step (3)represents the expulsion by alcohol vapour of the enol type acetone adsorbed specieswhich is adsorbed instead on the catalyst surface28 ADSORPTION OF ISOPROPYL ALCOHOLTo discover the role of adsorbed alcohol and acetone in dehydrogenation, therate of reaction (2) was examined at various alcohol and acetone coverages. Theresults using fresh catalysts are shown in fig. 8.1 . 2 c-bDH 5 1.0 .50 100 150reaction time/&FIG. 9.-Formation of En at various coverages of IPO and En. IPO coverage in pmol (g cat)-'.Vacant site (S) : 17.9 pmol (g cat)-I (see text). (a) IPO = 9.81, (6) IPO = 19.7, (c) IPO = 32.7, (d)IPO = 36.6, (e) IPO = 50.8.The initial rate of formation of enol type adsorbed species was second order withrespect to IPO(a) coverage in the initial stage of the reaction, which suggests thatinitially IPO(a) can react with dissociatively adsorbed hydrogen H(a) to form enolspecies.The preadsorption of acetone (En) inhibited this reaction, demonstratingthat the initial rate of En formation is proportional to the vacant site (S) for Enadsorption (fig. 9). Summarizing these data the following equation was obtainedd[En(a)]/dt = k[IPO(a)][H(a)][S - En(a)].An overall mechanism for the reaction is thus proposed :CH3ICCH3 CH3 CH3 CH3HzW I \\ /CHOH 0 1 Zn\ /CH ZnO l - 1 + H + HZC".. .. .:.' OHI 1Zn 0CH3 CH3 CH3 CH3 (V)\ /C\ /CHI + H + II 0 I 0I 0cH3\c y3HO ' '*___3Z0. KOGA, T. ONISHI AND K . TAMARU 290. V . Krylov, Catalysis by Nonmetals (Academic Press, London, 1970).Y. Dechatre and S. J. Teichner, Bull. SOC. chim. France, 1967, 8, 2804.D. J. Wheeler, P. W. Darby and C. Kemball, J. Chem. SOC., 1960, 332.K. Tamaru and T. Onishi, Appl. Spectr. Rev., 1975, 9, 133.K. Tamaru, Ado. Catalysis, 1964, 15,65.R. C. Mehrota and M. Arora, 2. anorg. Chem., 1969,370,300. ’ C. Tanaka, Nippon Kagakuzasshi, 1962,83,661.* K. Nagai, K. Tanaka and K. Miyahara, Bull. Chem. SOC. Japan, 1974,47,2847.Y. N. Rufov, A. A. Kadushin and S. Z. Roginsky, Proc. IVth Int. Congv. Catalysis (MOSCOW,1968), vol. 3.lo Y. Kubokawa, T. Ono and N. Yano, J. Catalysis, 1974,34,117.l1 N. Hillis, T. Francis, M. Ori and M. Tsutsui, J. Amer. Chem. SOC., 1974, 96,4800.l2 Y. Wakatsuki, S. Nozakura and S. Murahashi, Bull. Chem. SOC. Japan, 1969, 42,273.l 3 F. A. Cotton, J. N. Francis, B. A. Frentz and M. Tsutsui, J. Amer. Chem. SOC., 1973,95,2483.l4 J. K. P. Ariyaratne and M. L. H. Green, J. Chem. SOC., 1964, 1.l5 K. Nagai and K. Miyahara, J. Res. Inst. Catalysis Hokkaido Univ., 1975, 23, 110.(PAPER 7/2222

ISSN:0300-9599    

DOI:10.1039/F19807600019

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980,76, 30-42Construction of a Kinetic Model for the Iodine CHJPhotodissociation LaserCalculation of Cross-sections and comparison with ExperimentBY ANGEL COSTELA, JUAN M. FIGUERA, MARGARITA MART~N, JUAN M. PBREZInstituto de Quimica Fisica " Rocasolano ",C.S.T.C., Serrano 119, Madrid-6, Spain.AND LUIS VALLEReceived 20th November, 1978The known dependence of the reactivity of the methyl radical formed in CH31 photolysis uponirradiation wavelength has been explicitly introduced in an attempt to derive a kinetic model of theCH31 laser. The model was used to derive the cross-section for stimulated emission, u3+4 =5.6 x lo-'' cm2, in accordance with other reported values. Furthermore, the model gives a quantita-tive estimate of the final product concentrations, the effect of sulphur hexafluoride, the time-dependentbehaviour of the laser and the gain.These are all in reasonable agreement with previously deter-mined experimental results.Since the first reported laser emission in the flash photolysis of CH31 and CF31,'a variety of iodides have been shown to yield population inversion and laser action.However, only a few have the characteristics suitable for high energy operation (e.g.,for nuclear fusion investigation). From the photochemist's point of view two of thedesired features are: high yield of excited iodine atoms, I(2P4), shown in this workas I*, producing proportionally high population inversions (AN) and slow quenchingof these excited atoms. These characteristics have been studied for a variety ofsystems [e.g., ref.(2)]. With this background, attempts to construct kinetic modelsthat would pruvide additional information about the laser operation and quenchinghave been numerous. For example, a kinetic model has been proposed to interpretI2 formation in the flash photolysis of CH31 ; this suggests that the reaction,is of considerable importance.stress the role of quenching ofI* by the initially formed radicals. The high decomposition yields found undercertain conditions have been ascribed to pyrolysis.6* The rapid thermal equilibra-tion implied by this mechanism is explained by vibrational energy transfer from thehot radicals to the substrate. However, our preliminary report * on wavelengtheffects and repetitive operatiun of the CH31 laser introduces new observations thatthe reported models cannot explain.In particular, the pyrolysis hypothesis is toocrude ; a better approximation is required which takes into account the influence onsubsequent kinetic events, of the amount and type of energy (i.e., vibrational,translational, etc.) initially imparted to the photofragments. In this paper anattempt is made to develop an improved model. The different reactivities of vibra-tionally and translationally excited methyl radicals have been explicitly introducedinto the laser kinetic model and maximum use has been made of the data on elementaryreactions available in the literature. The number of arbitrarily chosen parametersI* +CH31 + CH3-+12,Other models used for CH31 and CF31 lasers 4 93COSTELA, FIGUERA, M A R T ~ N , PBREZ AND VALLE 31has been kept to an absolute minimum.On this basis we have tried to develop amodel for the CHJ laser that will approximate its time-dependent behaviour andpredict the after-lasing products and the gain, under different conditions of diluentgas pressures and illumination.The data presented indicate that the proposed model not only rationalizes previousresults but can yield information about some important laser parameters. Thecalculated cross-section for I* emission using this model agrees with the availableexperimental data. The results obtained have encouraged us to apply a similarapproach to lasers of more practical interest.THE MODELKINETIC MECHANISM USED IN THE MODELIn order to construct and probe the new model we have made extensive use ofexperimental data from ref.(8). The predictions made were compared to experi-mental results for the following cases: (A), methyl iodide with photolysis atil > 220 nm ; (B), as (A) but with the full arc of the Xe lamp ; (C), methyl iodidewith SF, in the ratio 1 :9 at ;Z > 220 nm and (D), as (C) but with the full Xe arc.Some of the observed laser parameters are sensitive to experimental conditions(cleanliness of windows and mirrors, alignment, etc.) and therefore exact agreementbetween calculation and experiment cannot be expected. We will return to thispoint later.The basic hypothesis from which the model is developed is the generation ofmethyl radicals with different kinds and amounts of energy according to the photolysiswavelength used.It will be shown later that this is supported by the availableexperimental data on CH31 photolysis. At wavelengths longer than 220 nmphotolysis of CH31 forms mainly low energy translationally excited methyl radicals ;on the other hand, below 220 nm the formation of highly energetic, vibrationallyexcited methyl radicals predominates. These radicals have different chemicalreactivities. The vibrationally excited radical is the more reactive, abstracting Hvery easily (E, = 9 kcal mol-l), while the main reaction of the translationallyactivated radical is recombination with other radicals. Evidence in favour of thesehypotheses is found in reported laser data and in results from stationary CHJphotolysis and photofragmentation spectroscopy.O Following this line of axgu-ment we first developed a model for the simplest case in which only translationallyexcited methyl radicals were formed (i.e., the case in which the photolysis is atil > 220 nm). Once this model performed satisfactorily we extended it to cover theexperiments performed with the full arc of the Xe flash lamp.For photolysis at wavelengths longer than 220nm the mechanism can be re-presented by reactions (1)-(19) of table 1. In the following discussion, reactionnumbers are those used in table 1 ; this table also includes the rate constants used inthe calculations and pertinent references.The process is initiated by the flash photolysis of CH31 when, for A > 220 nm,translationally excited methyl radical (CH,.), and atomic iodine ( R 90 % is excited2)are produced, reaction (1).The excited iodine can contribute to the laser emission,reaction (2), or it can be deactivated by collisional quenching with the substrate,reactions (3) and (4), or with other products, reactions (5)-(9).The quenching of I* by reactions (3)-(6) has been extensively studied 11-14 andwell established rate constants can be introduced into the model.Donobue and Wiesenfeld l1 found that the combined effects of reactions (7) and(8) on laser emission is five to ten times that of the alkyl iodide. They estimate32 IODINE CH3I PHOTODISSOCIATION LASERTABLE PHYSICAL AND CHEMICAL PROCESSES INCLUDED IN THE CH31 LASER MODELlengths are present processes (20)-(24) are included.Processes (1)-(19) are used for photolysis at wavelengths > 220 nm ; when shorter wave-processrate constant source/molecule-l cm3 s-l or footnote)(reference numberhv(1) CH3I + (CH3)t+I*(I)A > 220 nm(2) I* + I + ~ V a' = i 3 1 5 m(3)(4)I* + CH3I + I2 + CH3*I*+ CH3I + I+ CH3I( 5 ) I*+I2 + I+I,(6) I*(+ M) -+ I(+ M)(7) I*+ CH3- -+ I+ CH3-( 8 ~ ) I*+CH3*(+M)+ CH,I(+M)(8b)(9)(10)(1 1)(12)(13) I+I+CH3I+ Iz+C&I(14) I+I+I2 + 212(15) I+I(+ M) + I2(+ M)(16) CH3*+CH,*(+M) + C2H6(+M)(17) CH3*+12 + CH3Ii-I(18a) CH3*+I(+ M) + CH,I(+ M)(1 8b)(19) CH2I*+ CH21- + C2H4+12(20) cH31 + (CH3-),+1* i12 < 220 nm(22) (CH3.),+CH3I+ CH3-+CH31I*+ (CH3*)t -+ I+ CH3.(CH,*)t+ CH31 + CH4+ CH2I(CH,*)t+ CH31 + CH3*+ CH31(CH,*)t(+ M) 4 CH3*(+ M)hv(21)(23) (CH,*)v(+M)+ CH3*(+M)(24) (CH3*)v +I*+CH3* +I(CH,*)V+ CHJ + CH4+ *CHpI1.33 x 10-134.3 x 10-132 .4 ~ 10-173.6 x 10-l11 . 6 ~ 10-l21 . 6 ~ 10-l22.5 x 10-l12.5 x 10-l21 . 1 6 ~1 . 1 6 ~ 10-l21 . 6 ~ 10-133.1 x 10-312 . 5 2 ~ 10-304.1 x 10-333 . 6 6 ~ 10-l18.3 x1 . 1 6 ~1.5 x 10-lo2.5 x2.5 x1.ox 10-l12.5 x(a) Pure CH31 (Le., M = CH31); (b) same reaction, but M = SF6 (experiments withC&I-/SF6 in the ratio 1 :9) ; (c) estimated in this work, see text ; (d) used for estimation ofthe final ethylene concentration, assuming that (19) is the only CH21- reaction (it is notincluded in the kinetic scheme); (e) in cm6 s-l.k , +k, w 5 x cm3 molecule-l s-l.Palmer and Padrick obtained a similarvalue for k,. Of course, the presence of inert gases will influence k8 and the cor-responding reaction with ground state iodine. We will return to this point later.The quenching of I* by activated radicals, reaction (9), may play an importantrole when the substrate pressure is low and there is no inert gas present. The rateconstant for this process has been taken to be slightly higher than for the analogousreaction with thermal methyl radicals.In calculations for the cases without inert gases the combined effect of reactions(7)-(9) has been made roughly equal to that reported by Donohue and Wiesenfeld.llThe rate constants for translationally excited methyl radicals, reactions (10)-(12)COSTELA, FIGUERA, M A R T ~ N , P ~ R E Z AND VALLE 33have been deduced from our previously reported experiments.The formation ofz 1.5 % of methane allows us to estimate the rate constant for reaction (10) to beabout 1/70 of that for collisional radical deactivation with CH31. This rate constantfor collisional deactivation is given by Z/N, where 2 is the collision rate and N isthe number of collisions required to decrease the energy of the radical to < 1 kcalmol-l. The fraction of energy lost per collision, AE/E, may be obtained from theexpression, AE/E = 2mlm2/(ml+m2)2 where ml and m2 are the masses of thecolliding entities. The rate constants kll and k12 can be estimated.15Recombination reactions and the reaction of I2 with thermalized methyl radicalscomplete the model, reactions (13)-( 19).Reaction (19) is considered negligible andhas not been included in the kinetic model. This assumption is obviously unjustifiedin the case of massive photodecomposition but under such conditions the wholemechanism would be too complicated to be amenable to analysis. The inclusion ofreaction (19) is, however, necessary to explain the presence of ethylene in the photolysisproducts. These products may be of no importance during the laser emission, butthe model gives a rationale for their formation and also an estimate of their finalconcentrations.Reliable data are available for reactions (13)-(17), 6-20 consequently only reaction(18) need be discussed. The values available for the rate constant for this methylradical and iodine recombination differ by two orders of magnit~de.~.11* 21 Thisdifference and the crucial role of reaction (18) in the photodecomposition forced us tothink caxefully about this process. In other alkyliodides this rate constant has beenfound to be similar in magnitude to that for the alkyl radical recombination.22However, in CF31 a strong pressure dependence has been Some experi-mental data 24 helped to clarify this point. The CH31 photodecomposition quantumyield measured in our laboratory for the flash photolysis at 6 Torr for A > 220 nm,under the same conditions as used in the laser experiments, was found to be slightlybelow 0.9. This indicates that 10-15 % of the CHJ photolysed recombines to theoriginal substrate (the primaxy photodecomposition of CH31 has QD = 1).WhenSF6 is present in the ratio 9/1 the experimental OD is lowered to M 0.25; this isascribed to the effect of SF:, on recombination [reactions (8) and (18)]. These dataprovide the ratio of recombination to C2H6 to recombination to CH31. As themethyl recombination is well established, a good estimate for the other recombination(k18 + k,) can be obtained. The ratio k18/k8 can be deduced from the effects of theserate constants on the population inversion. The individual rate constants can thenbe obtained.When the full xenon arc is used, CH31 photolysis at A < 220 nm [reaction (20)lmust be added to the model. This process forms excited iodine I* and groundstate I and vibrationally excited methyl radical, (CH,.),.This radical may abstracthydrogen, reaction (21), or be collisionally thermalysed by the substrate, reaction (22),or by some inert gas, reaction (23). Finally, we have to include the analogue ofreaction (9), i.e., the quenching of I* by (CH,.),, reaction (24).The values of k21-k23 are based on the results of Callear and Van der B e ~ g h . ~ ~The ratio methane :ethane found indicates similar rates for abstraction and de-activation (i.e., kzl M kz2) in pure CH31 [see also ref. (26)]. The effect of SF6 onthis experimental ratio allows (k22/k23) to be estimated.PHOTON DENSITY RATE EQUATIONFour different processes that affect the photon density should be included in thisequation : spontaneous and stimulated excited iodine emissions, ground iodine1-34 IODINE CH3I PHOTODISSOCIATION LASERabsorption and cavity losses.The first is only important as a laser trigger; it wasneglected, but a small photon density was allowed at all times.The cavity losses, f, defined as WF/ Wl = 1 -f( W, and WI are the fkal and initialintensities, respectively), were estimated at 26 % for light travelling a complete cyclewithin the cavity. Losses for the numerical integration program could be definedas a rate constant of photon density + decrease (loss coefficient) : -d+/dt = p+.Integration over the time needed by the light to complete a cycle in the cavity,assuming intensity and photon density to be proportional, yields the equation :where L is the cavity length and the other symbols have their usual meaning.Thevalue of p obtained was 112 ,us1.The definition of the cross-section to be used in the photon density equationrequires some discussion, especially in connection with the hyperhe levels involvedin the transition.The collisional mixing or cross-relaxation between the upper hyperfine levels ofthe iodine transition is expected to be much slower than for the lower levels.27However, the results of Alekseev et aZ.28 show that cross-relaxation between theupper levels can be essentially complete at sufficiently high pressure and that oscillationof the F = 3 3 4 transition totally suppresses the other possible hyperfine transitions.If we assume that cross-relaxation is faster than any other process affecting thepopulations and that the hyperfine level populations are distributed according tolevel degeneracies, them we may write :where + is the photon density ; t, the time ; c73-,4, the cross-section for the I; = 3 3 4transition; gt=3 and g$=,, the degeneracies of the F = 3 and F = 2 levels of theexcited iodine; I* and I the total populations of the upper and lower levels, withtotal degeneracies g* and g, respectively ; and b, the loss coefficient.PUMPING SIMULATIONThe sum of two lorenzians, normalized and having the parameters described intable 2, gives an adequate representation of the flash (see fig.1). The total lightTABLE 2.-PUMPING SIMULATION AT 500 Jtime dependent proiileparameter of the lorenzian used aabsorbed photon density/photons ~ r n - ~I I1 A > 220 nm 1 < 220 nmf.w.h.m./,us 7 7.5 1.41 x 10l6 7.5 x 10l6time of maximumlps 10 22a Experimental data, ref. (8) and (24) ; normalization of the simulated curve to theexperimental flash was performed below 30 ,us where the match between them is goodCOSTELA, FIGUERA, M A R T ~ N , PBREZ AND VALLB 35quanta absorbed at A > 220 nm was determined in our laboratory, the quantumyield of I* used was 0.92.2 At A > 220nm both the quantum yield (taken asThe values used are givenin table 2. We have checked the dispersion for these figures (A > 220 nm) whichcan be introduced in the model and still give a reasonable description of the experi-mental results. Total decomposition is sensitive to the light absorbed and the laserpulse width to the I* quantum yield.We have observed that changes of -130 % inthe number of absorbed photons and about half of that for the I* quantum yield canbe tolerated by our model.= 0.5) and the light absorbed had to be estimated.0 5 10 15 2 0 25FIG. 1.-Flash profile introduced into the model (see text), dashed line. Experimental flash used,from ref. (S), solid line.NUMERICAL INTEGRATIONProgram DESUB 2 9 was used for the numerical integration of the differentialequations. The method is based on fitting the approximations to a rational functionof the discrete interval h and subsequent extrapolations to zero interval size, h = 0.Rational extrapolation is applied to a modified midpoint integration rule.ps and the con-centrations of the products were printed every 0.1 ps.On completion of the integra-tion, the program plots the evolution of the dependent variables against the inde-pendent variable.Some problem emerged in the first attempts to use the program. The integrationof the equations was initially unsteady; the computing time was excessive and theprogram did not converge. These difficulties are mainly due to the sudden and largechanges in the photon density value with time. The routine behaviour was consider-ably improved by using a relative error concept as the convergence criterion insteadof the initial standard error. However, attainment of adequate stability required theimposition of two restrictions, unless the photon density exceeded a minimum valueand the population inversion reached a threshold, rate of photon density change wastaken as zero.In ordinary conditions the initial integration step was 0.1 36 IODINE CH31 PHOTODISSOCIATION LASERMass balance was not explicitly introduced into the equation; therefore, itcould be used as a check on the reliability of the computed results.We found thatwith the program used, which gave concentrations to three significative figures, thesum of the rounding errors was higher than the mass balance deviation. Thisevidence suggests that the routine accumulative errors are < 0.1 %. Initial conditionswere those used in the experiments. *RESULTS AND DISCUSSIONDECOMPOSITION PRODUCTSThe products should properly be referred to as products formed in the flashphotolysis of CH3T, because their formation is not sensitive (within the errors ofcalculated and experimental data) to the attainment of laser oscillation in the experi-ment.Therefore, the products are unaffected by the rate of photon density changeand consequently by the cross-section for stimulated emission. For this reasoncross-sections are discussed later.The concentrations of CHJ and the main photodecomposition products, C2H6,CH4 and I,, are plotted against time in fig. 2 and 3. From the asymptotic characterof the resulting graphs (excluding I,) it can be deduced that the reaction after 30 p sis near completion. Therefore, values calculated at 30 p s can be considered a goodapproximation to final values and are compared with experimental results in table 3.The agreement between experimental and calculated values is reasonable.The model quantitatively explains the effects of the different factors that play arole in CH31 decomposition.Thus, the high level of decomposition found onirradiation without a filter or inert gas is shown by the model to be the consequence of2 0 LI I I 1 I i I0 5 10 15 20 25 30tlNFIG. 2.-Photochemical CH3I laser. Calculated methyl iodide concentration plotted against timefor the four cases studied. (-a - -), case (A), CH31, h > 220 nm ; (- - -), case (B), CH31, full Xearc ; (-), case (C), CH31/SF6 in the ratio 1 /9, h > 220 nm ; (- o - o), case (D), CH31/SF6 inthe ratio 1/9, full Xe arcCOSTELA, FIGUERA, M A R T ~ N , P I ~ R E Z AND VALLE 373.02.52.01.51.00.50 5 10 15 20 25 300 5 10 15 20 25 30 0 5 10 15 20 25 30tlPSFIG.3.-Photochemical CH31 laser. Calculated time evolution of the generated products, eachgroup of curves corresponds to one of the cases studied. (A), CH31, A > 220 nm ; (B), CH31,full Xe arc ; (C), CH3I/SF6 in the ratio 1 /9, h > 220 nm ; (D), CH3I/SF6 in ratio the 1 /9, full Xe arc.TABLE 3 .-MODEL CALCULATIONS OF THE CH3I LASER DECOMPOSITION PRODUCTSresults are given as percentages ofthe initial methyl iodide concentrationCH31 C2H6 CH4 C2H6conditions' calc. ref. (8) calc. ref. (8) calc. ref. (8) calc. ref. (8)(A) CH31, J. > 220nm 5.53 6.01 2.24 2.97 0.08 0.08 0.04 -(B) CH31, full uc 42.46 56.68 5.29 6.20 15.14 19.32 7.57 12.47(C) [CH3II/[SFc,I = 1.9,J.> 220 nm 2.77 1.83 1.18 0.90 0.008 0.03 0.004 -(D) [CH3Il/[SF,I = 1.9,full arc 10.15 9.35 4.09 3.57 0.77 0.89 0.39 0.66' Corresponding to the four cases studied in ref. (8)38 IODINE CH3I PHOTODISSOCIATION LASERtwo factors, (a) an important increase in light absorption (CH31 absorbs very stronglyat 3, < 220 nm) and (b) the role of the vibrationally excited methyl radical [reactionThe effects of wavelength and inert gases are, as seen in table 3, adequatelyreproduced by the program. The strong influence of SF6 on iodine-methyl radicalrecombination [reaction (8) and (18)] is noteworthy. The agreement between theresults and the calculated values is not surprising since the model was constructedusing the experimental results to introduce some of the unknown rates.Whatshould be stressed is the ability of the model to reproduce other laser parameters,such as gain, cross-section and time-dependent behaviour, under a variety of experi-mental conditions (see below).(201.POPULATION INVERSION CALCULATIONThe population inversion has been defined as AN = I* - (g*/g)I. The calculatedAN in the absence of laser emission is plotted against time in fig. 4. In these calcula-tions the rate of change of the photon density is made equal to zero and thereforethe calculated values of AN are not dependent on the cross-section, as mentionedpreviously.tlWFIG. 4.-PhotochedcaJ CHJI laser. Calculated population inversion in each case studied.(- - .), case (A), CH31, X > 220 nm ; (- - -), case (B), CH31, full Xe arc; (-): case (C),CH31/SF6 in the ratio 1 /9, A > 220 nm ; (- o - o -), m e @), CH31/SF6 in the ratio 119, fullXe arc.The values of several positive and negative contributions to AN when AN is amaximum are given in table 4.The most relevant features of these data are discussedbelow. Although in every case quenching by CHJ is the quantitatively dominantdeactivation factor, the other contributions largely determine the shape of the ANcurves. Thus, full arc photolysis of CH31 is characterized by an early maximum inAN [see curve (B), fig. 41. The formation of strong I* quenchers, mainly I2 andmethyl radical, causes a sudden decrease in AN when the pumping by the flash isintense (and still increasing).The introduction of SF6 has dramatic effects; ACOSTELA, FIGUERA, MARTfN, PkREZ AND VALLE 39(curve D) attains a higher and longer lasting maximum. This is not due directlyto the reduction in photodecomposition products as might be expected (see table 3),but to the combined effects of SF6 on the deactivation of" hot " methyl radicals andthe subsequent reaction of these radicals with I to reform the substrate [reaction (18)].This removal of I favourably influences the value of AN. Obviously, these effectsare strongly diminished if radiation with 3, < 220 nm is suppressed; both primarydecomposition and formation of " hot " radicals being drastically reduced, SF6 isalso less active. These trends are present in the results.TABLE 4.-cALCULATED RATES (molecules ~ r n ' - ~ S-' X OF DIFFERENT PROCESSES THATAFFECT THE POPULATION INVERSION AT A MAXIMUMquenching I* positivecontributionsto ANquencherreact ionbconditions" CH31(3-4) I2 CH3*(7-8) CH3,-+ CH3,m pumping (18)(A) CH31, 3, > 220nm 3.9 0.51 0.28 0.02 4.75 0.24(€3) C&I, full arc 10.0 2.7 1.3 1 .o 12.8 2.6(c) [CH3a/[SF61 = 1/993, > 22Onm 3.57 0.57 1.21 0.002 4.44 1.17(D) [CH3II/[SF6] = 1/92full arc 10.4 4.2 6.7 0.04 11.4 10.3-" Corresponding to the four cases studied in ref.(8) ; see table 1 for reaction identifi-cation.CALCULATION OF CROSS-SECTION A N D GAINThe cross-section of stimulated emission is one of the most important laserparameters and was required for the calculation of the laser's time-dependent charac-teristics.Its calculation employing our calculated values of AN was considered animportant achievement of the model and a positive check of its performance.The small signal unsaturated gain, G, can be calculated as :where AN,,, is the maxima of the AN curve (see fig. 4). The other symbols and theunderlying assumptions have been described previously.As previously explained, the calculated AN do not depend on C T ~ ~ ~ . Therefore,by introducing into eqn (25) the calculated AN,,, [fig. (4)] and the experimentallyobserved gain [determined under conditions for which eqn (25) holds], the value of03+4 can be calculated.This procedure was applied to the simplest case, CH31 with il > 220 nm. Inthis case the number of reactions and the number of undetermined rate constantsare a minimum; it should therefore provide the most accurate results.The cross-section was calculated to be 03+4 = 5.6 x This cm2 at 6 Torr of CH3140 I 0 D I NE CH3I P HOTODI SSO CI AT ION LASERTABLE 5.-MODEL CALCULATED GAIN AND CROSS-SECTION OF THE CH3I LASER AND COMPARISONWITH SOME EXPERIMENTAL VALUESconditionsa63'4 gainb/10-18cm2 calculated ref. (8)(A) CH31, 2. > 220nm 5.6'(B) CH3T, full arc 5.6 1.87 1.9(C) [CH31]/[SF6] = 1/9, A > 220 nm 3.9 1.44 1.6(D) [CH31]/[SF6] = 1/9, full arc 3.9 2.54 2.1a Corresponding to the four cases studied in ref. (8) ; see text for definition and methodsof calculation ; Zuev et aL30 give a value of 5.2 at 7 Torr CF31.DBtlwFIG. 5.-Experimental (-) and calculated (---) time-dependent behaviour of the laser.(A)CH31, h > 220 nm ; (B) CH31, h > 165 nm ; (C) CHsIISF6, A > 220 nm ; (D) CH3I/SF6,h > 365nmCOSTELA, FIGUERA, MARTfN, PeREZ AND VALLE 41value can be compared with the value of Zuev et aL30 for 7.6 Torr of C3F,I, cr3 j4 =5.2 x 10-l8 cm2 (calculated from their values for the bandwidth, 0.419 GHz, and thespontaneous emission coefficient, A = 5 s-l). Our value at 6 Torr can be extra-polated to the case in which SF6 is present, using a sF6 broadening factor of5 MHz T ~ r r - l , ~ l giving o3 j4 = 3.9 x cm2. Using these values for the cross-section we can calculate the gain for the different cases considered from eqn (25),see table 5. Clearly, the calculated value for case (A) has no significance as thecalculation is merely the reverse of that made to evaluate For the other cases,the agreement between calculated and experimental results is good, being slightlyworse for the cases in which SF6 is present.However, these small discrepancies arewithin the errors than can be expected from this approach to the problem.CALCULATION OF THE LASER EMISSION TIME-DEPENDENT CHARACTERISTICSUsing the cross-sections calculated above we can now consider the time-dependentbehaviour of the laser which, as mentioned previously, is highly dependent on theseparameters. Calculated and experimental time profiles of laser output are plottedin fig. 5. The experimental reproducibility of laser initiation and duration is fair ;however, reproducible intensities are difficult to obtain since small differences inalignment cause large differences in intensity.In addition the time constant of thelaser detector is x 1 ps and with this resolution the results reported in ref. (8) onlyrepresent the envelope of a combination of peaks for which the fine structure is notavailable. To these limitations must be added the crude kinetic description of thecomplicated phenomenon of laser emission.Taking into account these intrinsic difficulties, the calculations give a fair agree-ment with experiment The narrow, fast decay signal of CH31 photolysed with thefull arc, curve (B) of fig. 5, is reproduced quite accurately. The widening of thepulse produced by either removing the short wavelengths, curve (A), adding SF6,curve (D), or both together, curve (C), is approximately reproduced.This indicatesthat the AN calculations are basically sound, since their time evolution is, togetherwith the cross-sections, the source of the time-dependent behaviour of the laser.We axe grateful for the numerous suggestions and criticisms of Prof. R. M. Utrilla.A. C. and M. M. held Fellowships from the C.S.I.C.; L. V. from the InstitutoEspaiiol de Emigracibn. This research was partially supported by the Comisi6nAsesora de Investigacih Cientifica y TCcnica.l J. V. V. Kasper and G. C. Pimentel, Appl. Phys. Letters, 1964,5,231 ; J. V. V. Kasper, J. H.Parker and G. C. Pimentel, J. Chem. Phys., 1965,43,1287.T. Donohue and J. R. Wiesenfeld, Chem. Phys.Letters, 1975,33,176 ; T. Donohue and J. R.Wiesenfeld, J. Chem. Phys., 1975, 63, 3130.D. M. Haaland and R. T. Meyer, Int. J. Chem. Kinetics, 1974, 6, 297.V. Yu. Zalesskii, Soviet J. Quantum Electronics, 1975, 4, 1009.R. E. Palmer and T. D. Padrick, J. Chem. Phys., 1976,64,2051.V. Yu. Zalesskii and E. J. Moskalev, Soviet Phys. J.E.T.P., 1970,30, 1019.E. V. Arkhipova, B. L. Borovich and A. K. Zapol’skii, Soviet J. Quantum Electronics,6, 686.A. Costela, J. M. Figuera, M. Martin and L. Valle, Chem. Phys. Letters, 1978, 53,478.G. M. Harris and J. E. Willard, J. Amer. Chem. SOC., 1954,76, 4678.lo S. J. Riley and K. R. Wilson, Disc. Furaduy Soc., 1972, 53, 132.T. Donohue and J. R. Wiesenfeld, J. Phys. Chem., 1976, 80,437.l2 R. J. Butcher, R. J. Donovan, C. Fotakis, D. Fernie and A. G. A. Rae, Chem. Phys. Letters,1975, 30, 398.197642 IODINE CH3I PHOTODISSOCIATION LASERl3 D. H. Burde and R. A. McFarlane, J. Chem. Phys., 1976, 64, 1850 ; D. H. Burde, R. A.McFarlane and J. R. Wiesenfeld, Chem. Phys. Letters, 1975, 32,296.l4 R. J. Donovan and D. Husain, Trans. Faraday SOC., 1966, 62, 1050 ; R. J. Donovan and D.Husain, Ann. Report Chem. SOC. Ser. A, 1971, 68.l5 J. G. Calvert and J. N. Pitts, Jr., in Photochemistry (John Wiley, N.Y., 1966), p. 648.l6 R. Engelman, Jr. and N. R. Davidson, J. Amer. Chem. SOC., 1960,82,4770.l7 D. L. Bunker and N. R. Davidson, J. Amer. Chem. SOC., 1958,80,5085.l8 J. A. Blake and G. Burns, J. Chem. Phys., 1971,54, 1480.l9 F. K. Truby and J. K. Rice, Int. J. Chem. Kinetics, 1973, 5,721.2o M. C. Flowers and S. W . Benson, J. Chem. Phys., 1963,38, 882.21 S. W. Benson, in 23ermochemicaZ Kinetics (John Wiley, N.Y., 1968), p. 67.22 C. C. Davis, R. J. Pirkle, R. A. McFarlane and G. J. Wolga, I.E.E.E. J. Quantum Electronics,23 T. Ogawa, G. A. Carlson and J. C. Pimentel, J. Phys. Chem., 1970,74,2090.24 J. M. Figuera and L. Valle, unpublished work.25 A. B. Callear and H. E. Van der Bergh, Chem. Phys. Letters, 1970,5, 23.26 J. R. Majer and J. P. Simons, A h . Photochem., 1964,2, 137.27 E. A. Yukov, Soviet J. Quantum Electronics, 1973, 3, 117.28 V. A. Aleskseev, T. L. Andreeva, V. N. Volkov and E. A. Yukov, Soviet Phys. J.E.T.P., 1973,29 P. A. Fox, in Mathematical Sofware, ed. J. R. Rice (Academic Press, London, 1971), p. 477.30 V. S. Zuev, V. A. Katulin, V. Yu. Nosach and 0. Yu. Nosach, Soviet Phys. J.E.T.P., 1972,35,31 W. Fuss and K. Hohla, Z. Natwforsch., 1976,31a, 569 ; H. J. Baker and T. A. King, J. Phys. D,1976, 12, 334.36, 238.870.1976,9, 2433.(PAPER 8/2016

ISSN:0300-9599    

DOI:10.1039/F19807600030

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980, 76, 43-38Effect of Solvents on Dipole Moment of MerocyanineBY ZBIGNIEW PAWELKA AND LUCJAN SOBCZYK”Institute of Chemistry, University of Wroc€aw, 50-383 Wroclaw, PolandReceived 11 th December, 1978The energies of long-wave electron transitions and dipole moments of 3-ethyl-2-thio-5(3’-methyl-thiazolidyl-2’-ethylidene) oxasazolidine-2,4-diene(I) were determined in a number of solvents ofdifferent activity. Variations in both quantities correlated with one another and may be describedby the relative contribution of the resonance structures.In the generally accepted theory explaining strong solvatochromism of mero-cyanine dyes it is assumed that the electronic ground and excited states of a moleculeare described by two resonance structures : non-polar (quinoid) and polar(benzenoid)where D and A are the electron donor (basic) and electron acceptor (acidic) parts ofthe dye molecule, respectively.An increase in solvent activity (this term covers its ability to interact both non-specifically and specifically with the dissolved molecule) leads to a continuous shiftin the electron density distribution, making the dye structure closer to its polarresonance form.Indirect evidence of the shift induced by the environment througha conjugated n-electron system from the donor to acceptor end of the dye moleculeis the existence not only of strong solvatochromism (both positive and negative) butalso of a strong shift in the stretching vibration band vco of the carbonyl group in theelectron acceptor part of the molecule l o p and of the n.m.r.signal of the methineprotons.7* l2 Also, for weakly polar merocyanines in non-active solvents there is anapproximately lineax relationship between Amax and the root of the number of con-jugated double bonds (which is characteristic of the polyene structure), whereas inactive solvents there is a linear relationship between Amax and n (a structure similarto the polymethine system).** l3 Direct evidence of such changes in the electronstructure should be an increase in the dipole moment of the molecule. Quantum-mechanical calculations of solvation changes in the n-electron density distributionperformed recently for model dyes indicate that such an effect should be large enoughto be However, the above results have not been experimentally verifieduntil now, probably because of the low solubilities of most dyes.We have been studying the solvent effect on the polarity of rnerocyanine withthe structural formula (I)0 0D- $.CH=CH -f. ,CH=A D If: CH-CH+ .CH-AHZC-S0 NZC C=CH-CH=C-I I- \ /NICIC444 DIPOLE MOMENT OF MEROCYANINEThis dye, being sufficiently soluble in aromatic hydrocarbons, oxygen solvents andCHC13 for dielectric measurements, exhibits a strong positive solvatochromism. Anincrease in environment activity should then lead not only to changes in the groundstate energy but also to a measurable distortion in its electron density distribution.EXPERIMENTALThe absorption spectra of the dye in solvents under investigation were measured on aSpecord Carl Zeiss-Jena spectrophotometer.The reading error vmax did not exceed250 crn-l. Permittivities were determined by the superheterodyne beat method at 200 MHzin apparatus described earlier.14 The measuring circuit enabled us to measure the capaci-tance with relative error AC/C < 1 x Densities were measured by the pycnometricmethod and were accurate to 40.1 kg m-3 and the refractive index for the sodium D linewith an AbM refractometer was accurate to +O.OOO 02. All measurements were made at298.16+0.05 K. Within the concentration range 1 x < x2 < 1 x linear depen-dences of E, d and n2 against molar fraction of the dissolved dye were obtained. The slopesof the straight lines E = el(l+ax2), d = dl(l+px2) and n2 = nf(l+Yx2) and their root-mean-square errors were determined numerically by the method of least squares.Themolar orientation polarization at infinite dilution (P2,) was determined from the valuesof a, p and y, assuming two different models of the local electric field. In the case of non-polar solvents, Hedestrand’s formula l5 based upon the Lorentz field model was applied :where subscripts 1 and 2 denote the solvent and dye, respectively, and M is the molecularweight.For polar solvents the Onsager field model l6 is required for calculations. Accordingto this model, the orientation polarization is expressed by the formula :( E - n2)(2& + n2)E(n2 +2)2 . P =Assuming that the polarizations are additive, the expression for the limiting value of theorientation polarization for a solute (P$%) was obtained by differentiating eqn (2) withrespect to x2 :Neglecting the dependence of solvent polarization against concentration, the final equationhas the form :In the light of the studies by Cumper and Langley l7 this assumption seems to be justifiedonly in the case when the Onsager procedure is applied.The solvents applied were purifiedand dried by standard methods.18 The measurements in chloroform and in trichloro-ethylene were performed with freshly purified solvents.RESULTS AND DISCUSSIONThe energy values of the lowest energy electron transition (ET(,)) determined forthe dye in a number of solvents with various properties are summarized in table 1and fig. 1. The dye is characterized by a strong positive solvatochromism whosemagnitude is close to that shown by a number of other merocyanine dyes.19-23 Thedye transfer from n-heptane to rn-cresol is accompanied by the highest variation iZ .PAWELKA AND L. SOBCZYK 45the n + n* transition energy of 29.4 kJ mol-l in the series of solvents studied. Fig. 1shows a correlation of the ET(I) values in various solvents with the correspondinglong-wave n -+ n* transition energies (denoted by Brooker et aL21 as xR) in weaklypolar merocyanine characterized by an unusually high positive solvatochromism.According to Brooker et aL21 the xR parameter is a sensitive indicator of most solventeffects which are essential for these dyes. The relationship between ETCI) and xRis described by the linear equation ET(I) = 158.31 3-0.532~~ with a high correlationcoefficient of 0.975 (without the point for m-cresol). Acceptable correlations are alsosatisfied (except for cresols) by the transition energies of a number of other com-pounds where a charge displacement takes place due to a conjugation.19-23 Com-parison of the band shift in aromatic solvents with the shifts in aliphatic solvents ofsimilar permittivities and dipole moments shows that the former have much higheractivities. The reasons for such behaviour should be attributed to the high polar-izability of their n-electron systems and hence to the considerable energy of polar-ization interaction.Highest energy shifts occur in solvents with proton donornature, such as phenol (244.1 W mol-l, 323 K), rn-cresol (242.1 kJ mol-l), aniline(248.1 W mol-l), acetic acid (253.9 kJ mol-l) and trifluoroacetic acid (249.5 kJmol-l).For this group of solvents the specific interaction through the hydrogenbond to the active centre of the acidic dye part [for (I) it is the carbonyl group] isxR/kJ moklFIG. 1 ,-Correlation between transition energies (in kJ mol-l)ET(I) and for various solvents.1, n-Heptane (271.5) ; 2, cyclohexane (270.2) ; 3, triethylamine (268.6) ; 4, carbon tetrachloride(266.9) ; 5, n-butyl ether (266.1) ; 6,p-dioxan ; 7, ethyl ether (267.9) ; 8,p-xylene (263.6) ; 9, n-butylacetate ; 10, mesitylene (265.8) ; 11, o-xylene (262.1) ; 12, toluene ; 13, benzene ; 14, tetrahydrofuran(262.1) ; 15, acetonitrile (260.6) ; 16, acetone (260.9) ; 17, chlorobenzene (259.4) ; 18, dichloro-methane (257.1) ; 19, 2,6-lutidine (259.1) ; 20, bromobenzene ; 21, n-butyl alcohol (258.1) ; 22,cyclohexanone (256.1) ; 23, chloroform ; 24, nitromethane (258.3) ; 25, ethanol (255.6) ; 26, pyridine(253.5) ; 27, benzonitrile (255.0) ; 28, methanol (255.3) ; 29, nitrobenzene (254.1) ; 30, aniline(248.1) ; 31, m-cresol(242.1)46 DIPOLE MOMENT OF MEROCYANINEpredominant.The energy of that interaction depends strongly on the electron donor(basic) properties of oxygen exhibited by this part of the molecule. Since theseproperties depend on the electron structure and thus vary from one dye to another,the shifts for cresols are excluded from a general correlation. For the Brooker dyethe deviation for rn-cresol (xR = 140.6 kJ mol-l) is 9.2 kJ mol-l.The magnitudeof the effect related to the formation of the hydrogen bond m y be evaluated in agiven case by comparing the effect of proton donor solvents and their methyl deriva-tives (under conditions where their macroscopic properties are similar). Energydifferences between the electron transitions in phenol and anisol = 258.5 kJmol-l) as well as aniline and N,N-dimethylanilnie = 256.8 kJ mol-l) are 14.4and 8.7 kJ mol-l, respectively.The charge distribution in the n-electron system of merocyanine depends, aboveall, on differences in the electron donor-acceptor properties of the conjugated mole-cular ends. This obvious statement is supported by the results of measurements ofthe dipole moments in a number of merocyanine dyes performed by Kushner andSmyth 24 and Syrkin and The latter authors found that a change in thelong-wave band position in a group of structurally similar dyes is correlated withchanges in the dipole moment.The effect of the environment on the dipole moment of merocyanine has beenuntil now proven only by semi-empirical quantum-mechanical calculations by theSCF m.0.TABLE 1 .-TRANSITION ENERGIES AND DIPOLE MOMENTS OF MEROCYANINE(I) IN VARIOUSSOLVENTSbenzene 262.1 28.1 1 f0.78 1.318&0.071 1.292k0.022 99.4k1.9 900.1 127.6 22.14k0.33toluene 262.6 23.86k0.42 1.421 f0.143 1.259h0.095 97.4k8.2 926.1 k23.6 22.44&0.27bromobenzene 258.6 16.06k0.32 -0.255+0.040 1.565k0.082 1 1 1.0k4.6 976.6S52.2 23.04-fO.60trichloroethylene 261.1 22.16&0.57 0.413+0.035 1.470&0.110 91.5k4.6 872.9rt49.4 21.81 h O .6 0dioxan 263.1 24.8110.76 0.518&0.040 1.128h0.034 91.6k2.0 793.8131.0 20.7810.40butyl acetate 264.3 8.23&0.21 0.799&0.091 1.101 4Z0.117 103.018.7 758.8-164.9 20.31 zt0.87(896.21 30.5)* (22.08 S0.37)*(902.4k 13.2)* (22.14&0.17)*chloroform 256.4 23.75zk0.71 -0.100&0.028 1.965h0.188 110.1 rt6.3 1171.8k93.1 25.25rt1.00(766.2&27.2)* (20.41 &0.37)** Calculated according to eqn (1).Our experimental results presented in table 1 indicate that a change in the dipolemoment really takes place and exceeds the experimental error. Note here somepurely methodological problems of dipole moment determination in merocyanines.First, it is striking to find good agreement between the dipole moments in non-polarsolvents determined by the Hedestrand and Onsager formulae.CHCl, and bromo-benzene exhibit a considerable increase in the molar refraction determined from therefractive index for the sodium D line and calculated by extrapolation of the Hede-strand formula. This increase results mainly from dispersion of the refractive indexalthough D&ne and Nolte 26 suggest that the n-polarizability of merocyanines showsa solvent dependence. It should be emphasized that dispersive variations of themolar refraction are comprised within the experimental error of overall polarizationand have no significant influence on the solvent dependence of the dipole momentfound above. In spite of the fact that theoretical calculations concern the n-electrondensity distribution and our values are the overall dipole moments, taking into accounZ.PAWEEKA AND L . SOBCZYK 47that solvent variations comprise mainly the n-electron system it is possible to findqualitative agreement between the results achieved by two different methods. Aquantitative compaxison of our results with those estimated theoretically is difficultmainly because the group of solvents we used in measuring the dipole momentscorresponds to a fairly nurow interval in the activity changes. Therefore, the solventinduced increase found in the dipole moment is not too high. It appeared impossibleto extend the solvents applied to the least active aliphatic hydrocarbons because of23-0I5.s 22-21 -20 -191 . 256 258 260 262 264&(I)/kJ mol-lFIG. 2.-Correlation between dipole moments and transition energies for merocyanine(1) in varioussolvents.limited solubilities of merocyanines. However, from a qualitative point of view,the theoretical predictions find a satisfactory confirmation in our results. Theactivity parameter ET(I) of the solvent may be roughly related to the hamiltoniandescribing the interaction between polarizable dye molecule and surrounding layerof solvent molec~les.~ The interaction term has the form H’ = A4LM, where c)LMis the potential created by the oriented solvent molecules and ;1 varies from zeroto unity depending on the activity of the solvent. In not too broad limits of 2 andETCI) values, a nearly linear relationship between the dipole moment and the ET(I)value should be expected. Within the solvent under investigation the relationshipbetween p and ETcI) presented in fig.2 is in fact linear. If this relationship were satisfiedover the entire activity range of solvents then the dye molecule transfer from n-heptaneto the most active rn-cresol would correspond to an increase in the dipole momentof x 16 x C m. This value is close to that obtained theoretically for penta-methinemerocyanine which is similar to (I) with respect to its electron structure.Dielectric studies confirm an insignificant effect of the dielectric permittivity, foundearlier by the spectroscopic method, as an electron structure disturbing factor. Thelargest difference in the dipole moments appears between n-butyl acetate and chloro-form (Ap = 5 x C m), Le., in media of similar permittivities.In the latter48 DIPOLE MOMENT OF MEROCYANINEwhich exhibits proton donor properties, specific interactions through H-bond forrna-tion ‘C=Od-. . . H-C- / might occur inducing an additional charge displacement./ \It seems that the solvent effect on the transition energy and polarity of merocyanineis similar in magnitude and direction to that found for hydrogen bonded complexesbetween p-nitrophenol and triethylamine investigated previ~usly.~’ The similarbehaviour results from a similar electron density distribution in both systems and theso lut e-solven t interact ion mechanism .The work was performed under a project supported by the Polish Academy ofSciences.Th.Forster, 2. Elektrochem., 1939, 45, 548.L. G. S. Brooker and R. H. Spraque, J. Amer. Chem. SOC., 1941, 63,3214.L. G. S. Brooker, G. H. Keyes, R. H. Spraque, R. H. Van Dyke, E. Van Lare, G. Van Zandt,F. L. White, H. W. J. Cressman and S. G. Dent, J. Amer. Chem. SOC., 1951, 73, 5332.A. I. Kiprianov and E. S. Timoshenko, Zhur. obshchei Khiin., 1947, 17, 1468.J. R. Platt, J. Chem. Phys., 1956,25, 80.E. G. McRae, Spectrochim. Acta, 1958, 12, 192.H. G. Benson and J. N. Murrell, J.C.S. Faraday II, 1972,68, 137.K. D. Nolte and S. Dahne, Adv. Mol. Relax. Inter. Proc., 1977, 10, 299.* S. Schneider, Ber. Bunsenges. phys. Chem., 1976, 80, 212.lo S. D h e , D. Leupold, H. E. Nikolajewski and R. Radeglia, 2. Naturforsch., 1965,2Qb, 1006.l1 D. Smith and P. J. Taylor, Spectrochim. Acta, 1976, 32A, 1503.l2 R. Radeglia and S. Dahne, J. Mol. Structure, 1970,5, 399.l3 F. Dorr, Thesis (T. H. Munchen, 1966), after ref. (12).l4 L. Sobczyk, Roczniki Chern., 1959,33,743.l5 G. Hedestrand, 2. phys. Chem., 1929,132,428.l6 L. Onsager, J. Amer. Chem. Soc., 1936,58, 1486.l7 C. W. N. Cumper and P. G. Langley, Trans. Faraday SOC., 1970,67, 35.l8 Technique of Organic Chemistry, Organic Solvents (New York, 1955), vol. vii.l9 S. Hunig and K. Requardt, Annalen, 1955, 592,180.2o M. A. Mostoslavskii and V. A. Izmail’ski, Zhur. obshchei Khim., 1962, 32, 1746.21 L. G. S. Brooker, A. C. Croig, D. W. Heseltine, P. W. Jenkins and L. L. Lincoln, J. Amer.22 J. Figueras, J. Amer. Chem. SOC., 1971,93, 3255.23 A. Le Benze, A. Botrel, A. Samat, P. Appriou and R. Guglielmetti, J. chim. Phys., 1978, 75,24 L. M. Kushner and C. P. Smyth, J. Amer. Chem. SOC., 1949,71,1401.25 E. A. Shott-L‘vova, Ya. K. Syrkin, I. I. Levkoe’v and M. V. Deichmeister, Doklady Akad.26 S . Dahne and K. D. Nolte, J.C.S. Chem. Comm., 1972, 1056.27 Z. Pawel-ka, and L. Sobczyk, Roczniki Chem., 1975,49,1383.Chem. SOC., 1965,87,2443.255.Nauk S.S.S.R., 1962, 6, 1321.(PAPER 812126

ISSN:0300-9599    

DOI:10.1039/F19807600043

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980, 76, 49-59Influence of Dipole Inter actions on Surface ReactionsBY JAY B. BENZIGER~Department of Chemical Engineering, Stanford University,Stanford, California 94305, U.S.A.Received 19th December, 1978Electrostatic interactions between dipoles of adsorbed molecules can influence reaction mechanismand kinetics. Repulsive interactions can increase the rate of surface reactions, whereas attractiveinteractions can decrease the rate of reaction because of an increased stability of the adsorbed species.With formic acid decomposition on Ni surfaces attractive dipole interactions resulted in the formationof a condensed surface phase, which decomposed with autocatalytic kinetics. The formation of thecondensed phase was affected by both crystallographic structure as well as adsorption temperatureby affecting the approach to an equilibrium configuration.Attractive dipole interactions also affect the orientation of molecules on a surface, thus facilitatingreactions that might not otherwise occur.The formation of methyl formate from formaldehyde on aW(100) - (5 x l)C surface has been attributed to the favourable alignment of formaldehyde moleculesstemming from attractive dipole interactions.Adsorbate-adsorbate (A-A) interactions affect the adsorption/desorptionbehaviour of gases on metal surfaces. LEED studies have shown that orderedphases are formed due to these interacti0ns.l Large changes in the isosteric heatsof adsorption result from repulsive interactions between adsorbates.2 In tem-perature programmed desorption experiments A-A interactions result in multipledesorption peaks.The effects of these interactions can be treated by statisticalmechanics and models have been developed to explain temperature programmeddesorption results in terms of adsorbate-adsorbate interaction^.^'^Most models have assumed the adsorbate interactions to be the result of indirectinteractions through the metal surface. Theoretical evidence for oscillatory indirectA-A interactions uia the substrate was first presented by Grimley.’ More recentlyEinstein and Schrieffer * have shown that the periodicity of this oscillatory behaviouris related to the periodicity of the substrate. These models have been useful inproviding a basis for the existence of A-A interactions, correlating well with theobservations for many ordered LEED patterns.Over forty years ago both Langmuir and Roberts examined some implications ofA-A interactions which they attributed to dipole-dipole interactions. 9-1 Mostmodern investigators have dismissed the importance of these dipole interactions ;however, recent studies of adsorption and reactions of organic molecules on singlecrystal metal surfaces indicate that dipole interactions are important in determiningreaction kinetics and in affecting reaction mechanisms. This paper discusses thenature of dipole-dipole interactions and how these interactions affected adsorption,surface reactions and reaction kinetics.DIP 0 LE-D I P 0 LE INTER A CTI ON SIn order to have dipole-dipole interactions an adsorbed species must possesseither a permanent dipole (e.g., the dipole of formaldehyde) or a dipole due tot Present address : Department of Chemical Engineering, Princeton University, Princeton, NewJersey 08540, U.S.A.450 DIPOLE INTERACTIONS I N SURFACE REACTIONSadsorption (e.g., oxygen adsorption on a metal will result in a polar M-0 bond).The adsorption of two such molecules can be represented as in fig.1. The totaladsorption energy for these two molecules can be written asEtotal = Eo + Econfigwhere Etotal is the total adsorption energy, Eo is the adsorption energy for isolatedmolecules and Econfig is the configurational energy due to adsorbate-adsorbateinteractions. The configurational term will include contributions both from theindirect interactions and the direct dipole-dipole interactions ; only the latter will beconsidered in the following discussion.FIG.1 .-Dipole orientation for adsorbed species.The interaction energy between two dipoles with dipole moments pl and p2 atlarge separation is given by classical electrostatics asPlP2 U = - -$2 cos O1 cos O2 - sin el sin O2 cos (41 - &)Iwhere Y is the distance between dipoles and the angles are as indicated in fig. 1. Ifit is assumed that the point dipole approximation is valid and that both adsorbedmolecules are in the same configuration then the above expression reduces toPLr3 u = --(3 cos 2e- 1). (3)The significance of eqn (3) is that it shows that the molecular orientation affects theconfiguration energy.If the dipoles were aligned normal to the surface the con-figuration would be repulsive ; whereas, if the dipoles lay in the plane of the surfacethe configuration would be attractive. The important feature to note is that if thedipole has a significant component in the plane of the surface it can lead to attractiveinteractions between adsorbates.The net effect of dipole-dipole interactions can be either attractive or repulsive,depending on the orientation with the surface. Both attractive or repulsive inter-actions will result in the binding energy being dependent on the adsorbate coverage ;however, the sign of the interaction will produce profoundly different effects in theadsorption process. At low coverage, repulsive interactions will result in adsorptionbeing approximately spatially random as that will minimize the effect of the repulsiveforces.Attractive interactions, on the other hand, will result in the adsorbedmolecules condensing into islands where the binding energy is enhanced comparedwith random adsorption. For a given attractive interaction potential (a) there willbe a critical temperature (T,) defined byu) Tc = -2R (4J . B. BENZIGER 51below which a condensed phase will exist in equilibrium with a diffuse phase on thesurface.12 Above the critical temperature a single diffuse phase will exist, withapproximately random distribution.The effects of A-A interactions can best be seen in temperature programmeddesorption experiments. Several previous investigators have treated the effects ofrepulsive A-A interactions on temperature programmed desorption using a quasi-chemical approximation.Adams has derived the following expression for therate of desorption from a square lattice when only nearest neighbour interactions areconsideredd8 l+& - - dt = r$)e[ 1 -1 +ys exp (-E,/itT)where 8 is the fractional coverage, Eo is the adsorption energy of an isolated moleculeand OJ is the interaction energy, This expression is also applicable for attractiveinteractions when the temperature is above the critical temperature, where randomdistribution is a reasonable approximation. Below the critical temperature, desorp-tion can be described as occurring from two phases, a condensed phase where the rateof desorption should be pseudo first-order and a diffuse phase where the rate ofdesorption is described as above.Desorption from the condensed phase can alsobe described by the above expression, but using a local fractional coverage which isunity in the condensed phase.Fig. 2 shows the desorption spectra as a function of adsorbate coverage for thethree cases of (a) no interactions, (b) attractive interactions and (c) repulsive inter-actions. For all three cases E,, was 102 kJ mol-l, the pre-exponential factor was1 x 1 O l 3 s-l and the heating rate (p) was 10 K s-l. An attractive potential of 2.6 kJmol-1 and a repulsive potential of 4.2 kJ mo1-1 were chosen as typical values ofdipole interactions in next nearest neighbour positions to generate the spectra shownin fig.2(b) and (c). (These values were obtained from assuming a dipole moment of1.7 D separated by 5 A. The orientations were 8 = 90" for the repulsive configura-tion and 0 = 30" for the attractive configuration.) The three cases can be seen togive quite distinctive desorption behaviour as a function of adsorbate coverage. Inthe absence of any interactions the dcsorption peak temperature shows no variationwith coverage. This was first pointed out by Redhead l3 and is the distinguishingfeature of a simple first-order reaction process. Atttractive interactions result inthe adsorbate being more stable on the surface than if no interactions were present.The enhanced stability causes the desorption peak to shift to higher temperaturewith increasing coverage, as shown in fig.2(b). This distinguishing feature ofattractive interactions has only been reported for polar molecules like formaldehyde,or formic acid,14* which has suggested the importance of dipole-dipole interactions.Repulsive interactions have been discussed previously with respect to through surfaceinteraction^.^'^ The desorption spectra in fig. 2(c) show that the binding energydecreased with increased coverage, due to repulsive interactions causing desorptionat lower temperatures than if no interactions occurred. In particular one observesa low temperature desorption peak above a fractional coverage of 8 = 3, as increasingadsorption above this point results in adsorbates being in nearest neighbour positionswhere the repulsive interactions are most significant.As will be discussed belowboth attractive and repulsive interactions have been observed experimentally andcan be explained as the result of dipole-dipole interactions52 DIPOLE INTERACTIONS I N SURFACE REACTIONStemperature/Kl.." t I I t 1 I I300 350 400temperature/J . B . BENZIGER 53I I I 1 I 1 I300 350 400temperature/KFIG. 2.-Temperature programmed desorption as a function of coverage for (a) 8 = 1 .O, (6) 8 = 0.75,(c) 0 = 0.50, (d) 8 = 0.25. (A) First-order desorption. (B) First-order desorption with attractiveinteractions w = 2.6 kJ mol-I. (C) First-order desorption with repulsive interactions w = 4.2 kJmol- l.EXPERIMENTAL EVIDENCE FOR DIPOLE-DIPOLE INTERACTIONSFORMIC ACID ON Ni(ll0) AND Ni(100)Attractive dipole-dipole interactions for adsorbed species were shown by Benzigerand Madix to have affected the kinetics of the decomposition of formic acid on Nisurfaces.Formic acid decomposed on Ni(ll0) and Ni( 100) via the dehydrationof two formic acid molecules to give a formic anhydride intermediate which sub-sequently decomposed by an autocatalytic process to yield H2, C02 and C0.15* l6Formic anhydride is a highly polar molecule and should display effects of dipole-dipole interactions. Benziger and Madix proposed that the dipoles are tilted at anangle of 37” to the surface such that there is an attractive interaction between theadsorbed intermediates, which explained the unusual kinetics observed. Thecalculated attractive interaction potential was 11 kJ mol-1 when all pairwise inter-actions were accounted for.The temperature for decomposition of the anhydridewas well below the critical temperature (T, = 660 K) so that one would predict thata condensed phase would form as the coverage increased. Condensation was clearlydemonstrated by the work of Ying l7 shown in fig. 3. At low coverages COz wasformed by the decomposition of the formic anhydride in the diffuse phase at 75OC.As the coverage was increased a condensed phase was formed, resulting in greaterstability of the formic anhydride intermediate, which thus decomposed at a highertemperature. The emergence of the high temperature peak was the indication ofcondensation54 DIPOLE INTERACTIONS IN SURFACE REACTIONSThe formation of a condensed phase on the surface was further exemplified bythe work of Falconer and Madix.18 Deuterated formic anhydride (derived fromDCOOH) decomposed at a higher temperature than normal formic anhydride.When DCOOH was first adsorbed on Ni(ll0) followed by adsorption of HCQOHtwo desorption peaks were observed for the CQ2 product, one coincident with D2desorption where the deuterated intermediate normally decomposed and the othercoincident with H2 desorption where normal formic anhydride decomposed.In25 50 75 100 125 150temperature/oCFIG. 3.-COZ desorption from formic acid decomposition as a function of c0verage.l'contrast to this behaviour was that for coadsorption of DCQOH and HCOOH,where a single C 0 2 desorption peak was found coincident with H2, D2 and HD at atemperature intermediate to those normally observed for HCOOH and DCOOHadsorption.These results clearly showed the formation of a condensed phase;consistent with the model for attractive dipole interactions proposed by Benzigerand Madix.One unique feature of these attractive interactions was the autocatalytic reactionkinetics. As desorption occurred the binding energy of the remaining adsorbatesdecreased as the configurational interaction decreased. This led to an accelerationof the rate with decreasing surface concentration, or in other words an autocatalyticprocess. Such autocatalytic behaviour was observed by Falconer et a P 9 where thJ . B. BENZIGER 55rate of reaction was observed to increase with decreasing coverage at constant tern-perature.To complete the discussion of formic acid decomposition on Ni the effect ofcrystallographic structure on the dipole alignment should be mentioned.TheNi(l10) and Ni(100) surfaces are shown schematically in fig. 4. Ying and Madix 2ohave shown that a four Ni atom cluster stabilized the formic anhydride on Ni(ll0)and proposed that the molecule was oriented such that the dipoles were alignedalong the (110) direction. As the (110) surface is misotropic there was a preferredOrientation for adsorption of the formic anhydride so that island condensation wasreadily effected. On the other hand, the (100) surf= is isotropic so that no preferredorientation for adsorption was indicated.The saturation coverage of the anhydrideon Ni(100) suggested that a six Ni atom cluster was required for adsorption of theanhydride. Initial adsorption in the diffuse phase on the Ni(100) surface wouldresult in the orientation of the molecules being random, inhibiting the subsequentalignment of the dipoles at higher coverages as shown in fig. 4 and hence reducing theoverall attractive interaction in the condensed phase. This was observed by Benzigerand Madix where the attractive interactions for Ni(100) were reduced by 50 % fromthose observed on Ni(110).15 . . . . .e l . .I. . @ t @ .(A) (B)atom; 'l , formic anhydride.FIG. 4.-Formic anhydride island structure on Ni surfaces. (A) Ni(l10), (B) Ni(100). e, NickelMETHANOL ON Ag(110)The oxidation of methanol to formaldehyde on an Ag(ll0) surface with adsorbedoxygen was studied by Wachs and Madix.21 They observed that the adsorption ofmethanol was induced by the presence of preadsorbed oxygen.Employing iso-topically labelled 1 8 0 2 and CH30D they were able to show that each adsorbedoxygen atom induced the adsorption of two methanol molecules which subsequentlyformed methoxy intermediates as shown in fig. 5. This figure shows that the methoxyintermediates were formed in pairs so that a pairwise dipole interaction was expected.The tetrahedral coordination of the carbon in the methoxy group forces the dipoleto be nearly normal to the surface so as to avoid repulsive interactions between themethyl group and the surface resulting in a repulsive force between the methoxyintermediates. The repulsive dipole interaction should then result in the decomposi-tion of the methoxy pairs by two sequential processes.In the first step the rate i56 DIPOLE INTERACTIONS I N SURFACE REACTIONSenhanced by the repulsive forces which reduce the stability of the methoxy inter-mediate. After the first methoxy has decomposed the second gains added stabilitybecause the repulsive dipole force has been eliminated and so the rate of decompositionis slower. The rate expression would bedo - = v(o, + 62) exp (- E,/RT) + V O ~ exp [ -(Ea- a)/RT]dt (6)where o1 is the coverage of the isolated methoxy, o2 is the coverage of the methoxypairs and u) is the repulsive interaction energy. In a temperature programmeddesorption experiment the dipole forces would result in two desorption peaks.D D CH,+ 2 H Z C O + H 2FIG.5.-Mechanism for methanol oxidation on Ag(l10).Furthermore, if repulsive dipole forces were important then one would expect theadsorbed oxygen sequentially to induce adsorption of one molecule, then another,resulting in the high temperature desorption peak growing to saturation followed bythe emergence of the low temperature peak. This behaviour, which is shownschematically in fig. 6 for v = 1013 s-l, E, = 105 kJ mol-1 and o = 10 kJ mol-l,is identical to the observations of Wachs and Madix for formaldehyde formationfrom methanol on Ag(l10). The repulsive interaction of 10 kJ mol-1 was deriveJ . B . BENZIGER 57by assuming a dipole moment of 1.7 D for the methoxy supposing it to be orientednormal to the surface and a separation of 4 A, which are typical values for methanoladsorbed at next nearest neighbour sties on the Ag(ll0) surface.22I I l a350 400 45 0temperature/KFIG.6.-Effect of pairwise repulsive dipoles on temperature programmed desorption.The repulsive interactions between methoxys were observed for low surfacecoverages (< 20 % of saturation coverage), indicating that the adsorbed intermediatesremained adsorbed in adjacent positions and did not establish an equilibrium con-figuration during the time period of the experiment. Establishment of equilibriumis dependent on the rate of diffusion across the surface. Diffusion is temperaturedependent so that the adsorption temperature will affect the approach to equilibriumand hence the interactions between adsorbates.This effect was also observed forformic acid decomposition on Ni( 110) where decreasing the adsorption temperatureof formic acid from 310 to 210 K resulted in an increase in the rate of decompositionof the formic anhydride and suppression of the autocatalytic kinetics.16 The loweradsorption temperature inhibited the diffusion of the formic anhydride to form acondensed phase, resulting in the increased reaction rate which occurred from thediffuse phase.FORMALDEHYDE O N w(100) -(5 X 1)cThe two previous examples have shown the effects of dipole-dipole interactionson the reaction kinetics. As a last example we consider a case where attractive dipoleinteractions influence the reaction mechanism.The adsorption of formaldehydeon a W(100) -(5 x l)C surface resulted in a complex reaction scheme in whichvarious hydrocarbons as well as CO and H2 were formed.14 The initial reactionstep was the decomposition of formaldehyde to CO and hydrogen, with much of thehydrogen reacting with adsorbed formaldehyde to form intermediates which led tohydrocarbon formation. The product desorption spectra were studied as a functionof formaldehyde exposure and showed the CO and H2 peaks, corresponding to theinitial decomposition step, shifted to higher temperature with increasing formaldehyd58 DIPOLE INTERACTIONS I N SURFACE REACTIONSevosure, similar to the effect seen in fig. 2 for attractive interactions. Furthermore,as the coverage was increased above some critical coverage methyl formate wasobserved to desorb at low temperature by a desorption limited process (i.e., methylformate desorbed at the same temperature as when methyl formate was adsorbed),below the temperature at which formaldehyde decomposed.H HHIRo.7.--Mechanism of methyl formate formation from formaldehyde.The coverage dependence of formaldehyde decomposition indicated that attractiveinteractions were important, so the alignment of the dipoles of two formaldehydemolecules was considered. Fig. 7 shows the alignment of formaldehyde moleculeson a surface due to attractive dipole-dipole interactions. As shown in fig. 7 thisorientation is favourable for a hydrogen transfer leading to the formation of methylformate.Attractive dipole interactions can thus influence the configuration ofadsorbed species facilitating reactions which might otherwise not occur.CONCLUSIONSA simple approach to the interactions between the dipoles of adsorbed moleculeshas been presented. In reviewing the experimental results for reactions of simpleorganic molecules on metal surfaces the importance of these dipole-dipole interactionshas been clearly demonstrated. The dipole interactions affect the orientation ofadsorbed molecules as well as the adsorption energy. The distances over which thesedipole interactions are of importance are much greater than the indirect interactionsdiscussed by Einstein and Schrieffer, so that for polar molecules the through spacedipole interactions would be expected to dominate.Furthermore, the dipole inter-actions can be strongly attractive, resulting in the formation of condensed surfacephases, as seen in the case of formic acid decomposition of Ni(l10).The author thanks Prof. M. Boudart and R. J. Madix for their encouragement inpreparing this manuscript. He also thanks the surface reactivity group of Prof. R. J.Madix for providing the fine experimental results supporting the ideas proposed here.This work has been done under the financial support of the Natonal Science Founda-tionJ . B . BENZIGER 59l G. A. Somorjai and H. H. Farrell, Ado. Chem. Phys., 1971,20, 215.J. C. Tracy and P. W. Palmberg, J. Chem. Phys., 1969,51,4852.J. C. Tracy, J. Chem. Phys., 1972,56,2736.D. L. Adams, Surface Sci., 1974, 42, 12.C. G. Goymour and D. A. King, J.C.S. Faraduy I, 1973,69,749.D. A. King, Surface Sci., 1975, 47, 384. ' T. B. Gridey, Adu. Catalysis, 1960, 12, 1. * T. L. Einstein and J. R. Schrieffer, Phys. Rev. By 1973, 7, 3629.J. K. Roberts, Proc. Roy. SOC. A, 1935,152,445.lo J. K. Roberts, in Some Problems in Adsorption (Cambridge University Press, Cambridge, 1939).l1 I. Langmuir, J. Amev. Chem. SOC., 1932,54,2816.l2 R. Fowler and E. A. Guggenheim, in Statistical Mechanics (Cambridge University Press,l4 J. B. Benziger, E. I. KO and R J. Madix, J. Catdysis, submitted.l5 J. B. Benziger and R. J. Madix, Surface Sci., 1979,79, 394.l6 J. L. Falconer, J. G. McCarty and R. J. Madix, J. Catalysis, 1973,30,235.l7 D. H. S. Ying, Ph.D. Thesis (Stanford University, 1978).l9 J. L. Falconer, J. G. McCarty and R. J. Madix, Surface Sci., 2974,42, 329.'O D. H. S. Ying and R. J. Madix, J. Inorg. Chem., 1978,17,1103.'l I. E. Wachs and R. J. Madix, Surface Sci., 1978,76, 531.22 Handbook of Chemistry andPhysics, ed. R. C . Weast (Chemical Rubber Co., Cleveland, 1968).Cambridge, 1956).P. A. Redhead, Vacuum, 1962,12,203.J. L. Falconer and R. J. Madix, Surfme Sci., 1974,46,473.(PAPER 8/2182

ISSN:0300-9599    

DOI:10.1039/F19807600049

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980, 76, 60-70Diffusion in 4A ZeoliteStudy of the Effect of Crystal SizeBY HAYRETTIN YUCEL-~ AND DOUGLAS M. RUTWEN*Department of Chemical Engineering, University of New Brunswick,P.O. Box 4400, Fredericton, N.B. E3B 5A3, CanadaReceived 15th January, 1979Sorption rates for N2, CH4 and C2H6 have been measured in different size fractions of synthetic4A zeolite crystals. Both the form of the uptake curves and the dependence of the time constanton crystal radius are entirely consistent with the assumption that the kinetics of sorption are controlledby intracrystalline diffusion, rather than by a surface barrier. Comparisons between differentsamples of crystals show large differences in diffusivity and the diffusivities are much smaller thanthe values derived from n.m.r.measurements,The large discrepancy between intracrystalline diffusion coefficients derived fromn.m.r. and from sorption rate measurements has been noted in recent publications.'.To explain this discrepancy Karger and co-workers have suggested that uptake ratesin a sorption experiment may be controlled by a surface barrier rather than by intra-crystalline diffusion? Evidence in favour of this hypothesis was derived from theresults of a recent series of sorption measurements carried out with crystals of differentsize.'. Diffusional time constants (D/r2) calculated from the uptake curves weresmaller than the n.m.r. values and did not show the expected dependence on thesquare of the crystal radius. However, the form of the uptake curves measured inthis and in other laboratories suggests diffusion control rather than a surface barriersince the initial uptake is generally proportional to the square root of time.Inprevious kinetic studies we therefore interpreted our uptake rate data in terms of thediffusion model but we had not previously confirmed directly the dominance of intra-crystalline diffusion by varying the crystal size. In view of the anomalous resultsobtained by Karger et aZ.,l. a more detailed investigation was required.The range of crystal sizes present in most commercial type A zeolites is = 1-4 pm.Crystals of this size are not easily separated into different size fractions and for adetailed investigation of the effect of crystal size, larger crystals are desirable.TOavoid the uncertainties involved in the comparison of crystals of different origin andthe possibility of differences arising from different degrees of ion exchange in smalland large crystals, we elected to synthesize our own crystals and to examine first thekinetic behaviour of the sodium form (4A), rather than the calcium form (5A). Inorder to minimize complications arising from concentration dependence of thediffusivity we confined our studies to the low concentration region in which theisotherms are essentially linear and the diffusivities nearly constant. The results ofthese studies show clearly that for a series of crystal samples of similar origin theexpected dependence of the time constants on the square of crystal radius is indeedobserved. There are, however, large differences in diffusivity between OUT own 4Acrystals and samples from various batches of commercial Linde 4A.t present address : Chemical Engineering Department, The Middle East Technical University,Ankara, Turkey.6H.YUCEL AND D. M . RUTHVEN 61EXPERIMENTALSamples of 4A zeolite crystals were synthesized by Charnell’s method and separatedinto convenient size fractions using Nitex micro-sieves. The crystals were identified byX-ray diffraction and chemical analysis. The diffraction patterns showed no perceptibledifference from commercial Linde 4A. Crystal sizes were determined by scanning electronmicroscope and optical photo-micrography and the size distributions of the various fractionsare shown in fig.1. The 21.5, 34 and 40 pm* crystals all originated from the same batchof crystals while the 7.3pm crystals were from a different batch, synthesized by the sameprocedure. Prior to the kinetic measurements the crystals were dehydrated slowly under avacuum of w Torr. In the initial dehydration the temperature was raised slowly(2-3 deg min-l) to 400°C and maintained at that level for 48 h. For subsequent regenerationa period of 12 h at 400°C was sufficient. Transient uptake curves were measured using aCahn vacuum microbalance system to follow the change in weight of a small sample of thezeolite (m 12 mg) when subjected to a step change in sorbate pressure. Diffusional timeconstants were calculated by matching the experimental uptake curves to the appropriatedimensionless theoretical curve calculated for an assemblage of cubic particles with theappropriate size distribution.The method of calculation was essentially similar to thatpreviously reported except that in the calculation of the theoretical uptake curve we useddirectly the measured crystal size distribution rather than approximating the size distributionby a normal distribution function. To avoid possible limitations from thermal effects orbed diffusion resistance: small samples were used and the sample was spread as thinly aspossible over the balance pan.1000.01 0.1 0.2 0.5 1 2 5 10 20 30 LO 50 60 70 80 90 95 98 99 99.5 99.8 99.9cumulative vol/ %(b) 21.5, (c) 34 and (d) 40 pm.FIG. 1.-Size distribution of 4A zeolite crystal samples plotted on log-normal paper.(a) 7.3,RESULTS AND DISCUSSIONThe equilibrium isotherms for the different size fractions of our own zeolitecrystals show good agreement, as may be seen from fig. 2. Henry’s law constants* These crystal sizes refer to the volume average diameters62 DIFFUSION IN 4A ZEOLITE( K ) and limiting heats of sorption (qo), calculated from the van't Hoff equation[K = KO exp (qO/RT)] are summarized in table 1 and comparative values of qo,obtained in previous studies, are given in table 2.Fig. 3 shows a representative set of uptake curves for N2 at O'C, measured overcomparable pressure steps with the three different crystal size fractions. Also shown1.61.41.21 .o0.80.60.40.20.02.8 11.4l O 6 I '**I 1.00.80.60.40.20.00.0 100 200 300 400pressure/TorrFIG.2.-Equilibrium isotherms for different size fractions of 4A zeolite crystals ( x , 40 ; 0, 34 ;A, 21.5 ; B, 7.3 pm). (i) 243, (ii) 273, (iii) 323, (iv) 348, (v) 389 and (vi) 423 K. (a) CH4, (b) CzH6,(4 NzH. YUCEL AND D. M. RUTHVEN 63are the uptake curves calculated from the diffusion model with D = 4.05 x 10-l2cm2 s-l, which is the average of the individual values calculated for each curve.Clearly both the form of the uptake curves and the variation in rate between thethree size fractions are well correlated by the diffusion model and there is no evidenceof any significant variation in diffusivity with crystal size.TABLE HENRY'S LAW CONSTANTS FOR SORPTION IN 4A ZEOLITEK/ 1 0-3 molecule &/I 0-6 molecule 40sorbate T/K cavity-l Tom-' cavity-l Tom-l /kcal mol-l15,) N2 243273323 0.721.33CH4 273323C2H6 323 13.7348389423 1.549.87 4.21.5 4.31.39 5.9The variation of the time constants (D/r2) with pressure and with crystal size isillustrated in fig.4. The equilibrium isotherms are essentially linear over the experi-mental range (except for C2& at 323 K and N2 at 243 K) and the diffusivities aretherefore essentially independent of sorbate concentration. The diffusivities forC2H6 at 323 K show a small increase with sorbate pressure, as is to be expected fromTABLE 2.-cOMPARISON OF HEATS OF SORPTION OBSERVED IN DIFFERENT INVESTIGATIONStemperature heat of sorptionsor bate references range/K /kcal mol-l194-273194-273194-323195-22321 5-277243-323194-273195-323195-223273-323296-273298-389273-293323-4236.8-6.45.1-5.05.7-3.37.1-54.354.25.4-5.34-2.85-44.36.47.047.55.64 DIFFUSION I N 4A ZEOLITEthe non-linearity of the isotherm ( D = Do d lnp/d ln c where Do is the correcteddiffusivity, based on a chemical potential driving force and d ln p/d In c is thegradient of the equilibrium isotherm in logarithmic form).Time constants calculatedfrom adsorption and desorption curves showed no significant difference.1.00.820.61cd c&-3 0.4ct:00.200 5 10 15 20 25 30 35dtls*FIG. 3.-Representative uptake curves for N2 at 273 K for three different size fractions of 4A zeolite.A, 7.3 ; 0, 21.5 and 0, 34 pm.The points are experimental, the lines are the theoretical curvescalculated according to the diffusion equation with D = 4.05 x lO-'O cm2 s-l. The correspondingand 0 , 1 . 4 x values of D/r2 are A, 30.3 x ; 0,3.5 xFig. 5 shows the diffusivities calculated from the experimental time constants(D/r2) for the different size fractions of our own crystals plotted against mean crystaldiameter. There is no significant trend of variation of the apparent diffusivity withcrystal size and the differences between the different size fractions are within themargin of experimental uncertainty. (An error of 10 % in the average crystal sizegives a 20 % error in the calculated diffusivity). Therefore, the kinetic data forsorption of N2, C2H6 and CH4 in our own 4A zeolite crystals are entirely consistentwith the assumption that intracrystalline diffusion is the rate controlling transportprocess and there is no evidence of a surface barrier.The temperature dependence of the diffusivities is shown in fig.6 and 7 in whichdata for several different samples of Commercial Linde 4A zeolite are included.Activation energies and pre-exponential factors are listed in table 3. For all threesorbates, our own zeolite crystals show the highest diffusivities although the valuesobtained for C2H6 by Brandt and Rudloff with very small crystals (0.7 pm) are verysimilar. In general the diffusivities of the commercial samples are smaller but thedifference is not related to crystal size, since there are quite large differences betweendifferent commercial Linde samples of similar crystal size.In order to confirm thatthe difference in diffusivities between the different samples is a real effect and notsimply the result of differences in experimental technique between different labora-tories, we carried out a series of experiments with the same sample of Linde 4Azeolite as used by Eagan and Anderson.ll Our data for C2H6 confirm exactly theextrapolation of Eagan's data. Although the diffusional activation energies aresimilar, the diffusivity for this sample is about half that for our own crystals undercomparable conditionsH . YUCEL AND D . M. RUTHVEN 658 006001 1 I I 1 I I .(4 pressurelTorr0.0 50 100 150 200 25010040I I I I(4 pressure/Torr-- +--44 002004 401I I I I I I0.0 25 50 75 100 125 150(b) pressure/Torr0.0 50 100 150 200 250 300(d) pressurelTorrFIG. 4.Dressure dependence of diffusional time constants for different size fractions of 4A zeolitecrystals.(a) CZH~ at 389 K; (b) CzHs at 273 K ; (c) Nz at 273 K ; (d) CH4 at 273 K. Averagecrystal diameter in pm as follows : +, 40 ; 0 , 34 ; A, 21.5 ; W, 7.3. Top dashed lines indicateLinde 4A : (a) and (b), Kondis (2.8 pm) ; (c) and (d), Eagan (4.1 pm).1-66crystal diameterlpmFIG. 5.-Diffusivities calculated from uptake curves for different size fractions of 4A zeolite crystals.(Error bars show k 15 % which was the range of experimental scatter in the individual time constantsfor each size fraction). (a) Nz, 273 K, (b) CzHs, 389 K ; (c) CH4, 273 K ; (d) CzHs, 323 K.FIG. 6.-Arrhenius plot showing tem-perature dependence of limiting dif-fusivity for Nz-4A.0, presentstudy with own 4A crystals; A,Eagan and Anderson; A, data ob-tained in this laboratory with zeolitesample of Eagan and Anderson, 0Ruthven and Derrah (Linde pellet) ;x , Habgood ; @, KumarH . YUCEL AND D . M. RUTHVEN 672.0 2.5 3.0 3.5 4.0103 KITFIG. 7.-Arrhenius plot showing temperature dependence of limiting diffusivity for CzHa-4A andCH4-4A. Except where indicated the data are for CzHs. 0, present study with own 4A crystals ; A, Eagan and Anderson; A, data obtained in this laboratory with zeolite sample of Eagan andAnderson ; +, Kondis, 4A crystal ; x , Kondis, crushed 4A pellet ; 0, Linde 4A lot 470017,present study ; V, Taylor, Linde 4A pellet ; , OKumar, Linde 4A pellet ; +, Brandt and Rudloff,Davison 4A.The data for N2 may be interpreted in a similar way.Our data for the N2system fall below the extrapolation of Eagan’s data and suggest a lower activationenergy. However, if our own data and Eagan’s data are taken together as one setcovering the entire temperature range 190-323 K, an acceptable Arrhenius plot isobtained with an activation energy similar to that for our own zeolite crystals.Despite the similarity in the activation energies the actual diffusivity values for Eagan’ssample are lower than the values for our own crystals by a factor of z 4.The diffusivities for some other samples of Linde 4A zeolite, determined in thislaboratory, are even smaller.Indeed, for C2H6 in Linde lot 470017 and for N2 in acrushed Linde 4A pellet l2 we observe diffusivities about two orders of magnitudesmaller than the values for our own crystals. The activation energy of N2 in thisLinde sample is essentially the same as for our own crystals but in the case of C2H68 DIFFUSION IN 4A ZEOLITETABLE 3 .-ACTIVATION ENERGIES ( E ) AND PRE-EXPONENTIAL FACTORS (D,) GIVING TEMPERA-TURE DEPENDENCE OF LIMITING DIFFUSIVITIES FOR VARIOUS SORBATES IN 4A ZEOLITE[Do = D , exp (-E/RT)]zeolite and av. temperature E D*investigator crystal diameterlpm rangelK jkcal mol-1 /lo-' cm2 s-laHabgood Linde 4A (0.5)Eagan and Anderson Linde 4A (4.1)lot 450339present study same sample (4.1)Derrah l2 Linde 4A (3.4)(crushed pellet)Kumar Linde 4A (3.5)(14-30 mesh)present study own crystals(7.3, 21.5, 34)CzHs-4ABrandt and Rudloff l3Kondis and Dranoff 14* l5Davison 4A (0.7)(lot 441079)Linde 4A pelletlot 450339Eagan and Anderson Linde 4A (4.1)Taylor Linde 4A (3.6)( 8 in.pellet)present study Linde 4A (x 3.2)(lot 470017)present study own crystals(7.3, 21.5, 34, 40)CHa4AaHabgood Linde 4A (0.5)Eagan and Anderson l1 Linde 4A (4.1)Kumar Linde 4A (3.5)(14-30 mesh)present study own crystals(7.3, 21.5, 34)194-273195-233243-32321 5-277304-363243 -3 23296-373298-389298-389273-323304-352323-389323-423194-273195-223305-366273-3234.075.86.16.05.67.45.665.237.25.66.38.27.48.26.45.80.00235.30.963 .O13.21.30.0620.0060.40.0050.0044.80.06360.410.9aThe mean crystal size of Habgood's sample was determined by the B.E.T.method whichis less reliable than photomicrography. The values of D, from Habgood's data are there-fore subject to some uncertainty. bThe data of Kumar were obtained by a chromato-graphic method while the other investigators used standard gravimetric, volumetric orpressure transient me tho ds .the activation energy for the Linde crystals appears to be smaller. However,in calculating the activation energy of C2H6 Kondis and Dranoff l4 and Taylor l 7take no account of the d h p l d In c correction factor. At the lower temperatureswithin their experimental range this factor is significantly greater than 1.0 and itsinclusion would therefore increase the activation energy of the limiting diffusivityH.YUCEL AND D. M. RUTHVEN 69The data for CH4 are similar although less extensive. There appears to be a largedifference in diffusivity between our own crystals and Habgood's commercial samplewith only a comparatively modest difference in activation energy. The data ofEagan and Anderson for CH4 do not extend over a sufficiently wide temperaturerange to permit a reliable determination of the activation energy.The consistency of the diffusivity values derived from the different size fractionsof our own crystals and the marked difference in diffusivities between our own crystalsand the Linde 4A pellet is further illustrated in fig.8 which shows data for N2 andAr at 273 I<. A slight decrease in the Ar diffusivity with increasing pressure isobserved for both zeolite samples whereas the diffusivity of N2 appears to be inde-pendent of pressure in this range. For both gases the diffusivity in the Linde sampleis lower by a factor of 30 compared with the value for our own crystals under com-parable conditions.lo-' '000 00 " 0 O0 0 w0 . . 07 10-gl .I 0 - mA - DL + t+I I I I + I t IPITorrown 4A zeolite crystals. (N2: A, 7.3 ; H, 21.5 ; 0 , 3 4 pm. Ar: 0, 34 pm).FIG. 8.-Comparison of diffusivities for N2 and Ar at 273 K in Linde 4A pellet (+ , x ) and in ourCONCLUSIONSThe results of the present study of sorption kinetics in a series of size fractions of4A zeolite crystals show clearly that for the systems investigated sorption rates arecontrolled entirely by intracrystalline diffusion and there is no evidence of anysystematic variation in diffusivity with crystal size.However, there are large differ-ences in diffusivity between some of the different zeolite samples, even though thereis no perceptible difference in the X-ray diffraction patterns. In paticular, for onecommercial sample, the diffusivity was nearly two orders of magnitude smaller thanthe value for our crystals. The reduction in diffusivity is generally associated with areduction in the pre-exponential factor, rather than with an increase in diffusionalactivation energy and in most cases the diffusional activation energy is actually lowerfor the slower diffusing sample.Such differences must be due to subtle changes inthe crystal structure which are not sufficient to cause noticeable changes in the latticeparameters and which therefore do not significantly alter the X-ray diffraction pattern.The most obvious possibility is a re-arrangement of the exchangeable cations. Com-mercial zeolite samples are generally marketed in dehydrated form so that the initia70 DIFFUSION IN 4A ZEOLITEdehydration is not controlled by the investigator. The importance of the initialdehydration conditions was clearly demonstrated by Kondis and Dranoff l5 whoshowed that by exposure to steam at elevated temperatures a reduction in diffusivityby more than an order of magnitude could be achieved, with little change in thediffusional activation energy, and that under these conditions there was no loss ofcrystallinity or sorption capacity.Such “ pore closure ” effects have been discussedby Breck.lRearrangement of the cations may be facilitated by exposure to steam at hightemperatures. A difference in cation distribution can produce small changes in thewindow dimensions which may alter the diffusional activation energy. However,the main effect is likely to be the complete blockage of a certain fraction of the win-dows. This will lead to large changes in the pre-exponential factor with little changein activation energy.lg This is the pattern of behaviour suggested by the presentdiffusivity data.The results of the present study stand in marked contrast to the results obtainedby Karger et aL3 for the 5A zeolite.A further study of the 5A system using differentsize fractions of the same zeolite sample was therefore carried out and the results arereported in the next paper.Of the systems studied in the present work the only one for which n.m.r. data arealso available is CH4-4A. N.m.r. self diffusivities for this system are w lo-’ cm2 s-lat 140 K with the activation energy < 2.0 kcal mol-1.20 This is very much largerthan the corrected diffusivity extrapolated from the present sorption data(Do M 1O-l’ cm2 s-l at 140 IS). However, the zeolite sample used in the n.m.r.studies was not a pure 4A sieve but contained w 20 % Ca2+.The present resultsshow that there may be considerable differences between the diffusivities for differentzeolite samples and, although it seems unlikely that such a large difference can beexplained simply on the basis of differences in the samples, it is evident that reliablecomparisons can only be made if identical samples are used.We thank Dr. R. B. Anderson of McMaster University for providing us with asample of the 4A zeolite used by Dr. Eagan in his diffusion studies.J. Karger and J. Caro, J.C.S. Faraday I, 1977,73,1363.D. M. Ruthven, A.C.S. Symp. Series, 1977, 40, 320.J. Karger, J. Car0 and M. Bulow, 2. Chem., 1976,16, 331.J. F. Charnell, J. Cryst. Growth, 1971, 8, 291.K. F. Loughlin, R. I. Derrah and D. M. Ruthven, Canad. J. Chem. Eng., 1971, 49, 66.Lap-Keung Lee and D. M. Ruthven, J.C.S. Farudczy I, 1979,75,2406.D. W. Breck, W. G. Eversole, R. M. Milton, T. B. Read and T. L. Thomas, J. Amer. Chm.Soc., 1956, 78, 5963.H. W. Habgood, Cunad. J. Chem., 1958,36,1384.’ Lap-Keung Lee, H. Yucel and D. M. Ruthven, A.C.S. Symp. Series, 1977,40,417.lo R. J. Farper, G. R. Stifel and R. B. Anderson Canad J. Chem, 1969,47,4661.l1 J. D. Eagan and R. B. Anderson, J. Colloid Interface Sci., 1975, 50,419.l2 D. M. Ruthven and R. I. Derrah, J.C.S. Faraday I, 1975,71,2031.l3 W. Brandt and W. Rudloff, J. Phys. Chem. Solids, 1965,26,741.l4 E. F. Kondis and J. S. Dranoff, Ado. Chem., 1971, 102, 171.l5 E. F. Kondis and J. S. Dranoff, Ind. Eng. Chem., Process Design Develop., 1971, 10, 108.l6 R. Kumar, Ph.D. Thesis (University of New Brunswick, Fredericton, Canada, 1978).R. A. Taylor, Ph.D. Thesis (University of New Brunswick, Fredericton, Canada, 1978).l 8 D. W. Breck, ZeoZite Molecular Sieves (John Wiley, New York, 1974), pp. 490-494, 645.l9 D. M. Ruthven, Cunad. J. Chem., 1974,52,3523.2o J. Caro, J. Karger, G. Finger, H. Pfeifer and R. Schollner, 2. phys. Chem. (Le@zig), 1976,257,903.PAPER (9/106

ISSN:0300-9599    

DOI:10.1039/F19807600060

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980,76, 71-83Diffusion in 5A ZeoliteStudy of the Effect of Crystal SizeBY HAYRHTTIN YUCELt AND DOUGLAS M. RUTHVEN*Department of Chemical Engineering, University of New Brunswick,P.8. Box 4400, Fredericton, N.B. E3B 5A3, CanadaReceived 15th January, 1979The kinetics of sorption of CF4 and n-C4Hlo have been investigated in different size fractionsof two different 5A zeolites with different Ca2+ contents. The results show that in the larger crystalsthe uptake rate is controlled entirely by intracrystalline diffusion while, in the small crystals, ratesare controlled by the combined effects of external heat transfer and intracrystalline diffusion.Diffusivities are independent of crystal size but there are larger differences between the differentzeolite samples.For both CF4 and n-C4Hlo, diffusion in conimercial Linde 5A crystals is verymuch slower than in the laboratory synthesized zeolite samples. Corrected diffusivities for butanein the fastest diffusing zeolite sample are within an order of magnitude of the values estimated fromn.m.r. relaxation measurements.The need for additional detailed studies of diffusion in 5A zeolite to clarify thediscrepancy between the results of Karger et aZ.lS who, in a study of the sorptionkinetics of CzH6, C3HS and n-C,H,, in 5A zeolite, observed a strong dependenceof the apparent diffusivities on crystal size and our own results, for the 4A zeolite,which show no such variation of diffusivity, was noted in the preceding paper.3The results of such a study are reported here for two sorbates (CF4 and n-C,H,,)in two different 5A zeolites with different Ca2+ contents.CF4 diffuses quite slowlyin 5A zeolite and, since the heat of sorption is relatively small (w 5 kcal mol-l),thermal effects are negligible and the uptake curves can be analysed according to thesimple isothermal diffusion model. Within the experimental range of temperatureand pressure the CF4 isotherms deviate only slightly from linearity and the diffusivityis therefore not strongly concentration dependent. By contrast n-C4Hl, is morestrongly adsorbed. Diffusion is faster and, since the isotherms are highly non-linear, diffusivities vary strongly with concentration. The Beat of sorption is higher(m 11 kcal mol-l) and uptake rates in the smaller zeolite crystals are stronglyinfluenced by heat transfer limitations.EXPERIMENTALThe experimental procedure was similar to that described in the preceding paper.3Details of the zeolite samples are given in table 1.The 34 and 7.3 pm crystals (samplesla and lb) were prepared by Ca2+ exchange from the appropriate size fractions of the 4Acrystals used in the preceding study. The 55 and 27.5 pm crystals (2a and 2b) were alsoprepared from the same original batch of 4A crystals as sample l a (34pm). In order toachieve a high degree of Ca2+ exchange (> 95 %) the crystals were contacted with calciumchloride solution for a prolonged period and then separated by sedimentation into two sizefractions with mean crystal diameters 55 and 27.5pm.The crystal size distributions areshown in fig. 1.t Present address : Chemical Engineering Department, Middle East Technical University,Ankara, Turkey.772 DIFFUSION IN 5A ZEOLITEElectron micrographs showed that the crystals of samples l a and 16 were well formedcubes with no noticeable cracks or defects whereas surface striations and defects were clearlyevident in the crystals of samples 2a and 26. It is not known whether these occurred duringion exchange or sedimentation. Details of the chemical analysis, as well as SEM photo-micrographs are given in the thesis of Y u ~ e l . ~TABLE DE DETAILS OF ZEOLITE SAMPLESmean crystal sidesample % Ca2+* /Pm originl al b2a 26 {>%by ion exchangepreceding paper7.3 from 4A samples ofby ion exchange andsedimentation from4A sample l a ofpreceding paper* Expressed as % of original Na+ ions replaced by Ca2f.crystal size/pm16 are as shown previously.)FIG. 1.-Crystal size distribution for samples 2u and 26.(The size distributions of samples la anH . YUCEL AND D. M. RUTHVEN 73.3I xY .As1 .a1.61 . 41 . 21 . o0.40.20.00.0 50 100 150 200pressure/TorrFIG. 2.-Equilibrium isotherms for CF4 in 5A zeolite crystals (0, 55 pm ; A, 27.5 pm).values of the Henry constants (molecule cavity-' Torr-') are : (a) 273 K, 0.021 ; (b) 323 K, 4.7 xI I(c) 362 K, 2.0 x 10-3.11 .O[The10-3;0 10 20 30 40 502/^f/S+FIG. 3.-Comparison of uptake curves for CF4 in samples 2a and 2b (55 and 27.5 pm crystals of 5Azeolite) measured over comparable pressure steps at 323 K.The theoretical curves are calculatedaccording to the isothermal diffusion model with the time constants D/r2 = 4.3 x loe4 (26) and9.1 x s-l (24. p = 41-24 Torr (2b) and 38-27 Torr (k)74 DIFFUSION I N 5A ZEOLITERESULTS AND DISCUSSIONSORPTION A N D DIFFUSION OF CF4The equilibrium isotherms for CF4 on the 27.5 pm and 55 pm 5A crystals areshown in fig. 2. There i s good agreement between the data for the two size fractionsand, except at the lowest tempzrature (273 K), the isotherms are nearly linear overthe entire pressure range. Correlation of the Henry constants (K, defined by c = Kp)according to a van't Hoff equation [K = KO exp (qo/RT)] gave KO = 1.49 x(molecule cavity-l Torr-l) and qo = 5.17 kcal mol-l.These values may be com-pared with the values obtained previously for Linde 5A zeolite (lot no. 550 045) : 5KO = 3 . 8 ~ qo = 5.9 in the same units. Over the experimental temperaturerange the Henry constants for our own zeolite sample are thus slightly higher thanthe values for the Linde sample.Representative uptake curves for the two different size fractions (samples 2aand 2b), measured over similar pressure steps, are shown in fig. 3. The curvesconform well to the simple isothermal diffusion model and the difference in uptakerates is essentially as expected from the difference in crystal size.(4 (b) (c)." 5 10 40 100 10 40 100 10 40 100p/TorrFIG. 4.-Variation of diffusional time constants and diffusivities for CFq in 27.5 pin (0, 0 ) and55 pm ( x ) crystals of 5A zeolite (samples 2a and 2b) with sorbate pressure.(a) 273, (6) 323 and(c) 362 KH. YUCEL AND D. M. RUTHVEN 75Fig. 4 shows the diffusional time constants, calculated by matching the experi-mental uptake curves to the appropriate solution of the diffusion equation, dulycorrected for the distribution of crystal size, plotted against sorbate pressure. At362 K the time constants are essentially independent of pressure but at the lowertemperatures there is a small increase with pressure which can be satisfactorilyexplained by the non-linearity correction (D = Do d lnpld la c). The time constantsfor the two size fractions show the expected difference (by a factor of w 4) so thatat all temperatures diffusivities calculated for the two size fractions are essentially thesame.The temperature dependence of the limiting diffusivity (Do), correlatedaccording to an Arrhenius expression [Do = D* exp (-E/RT)], is given in fig. 10and in table 3.50 100 0 50 100 150 0 50 100 0plTorrFIG. 5.-Equilibrium isotherms for n-C4Hlo in 5A zeolite crystals. (Sample la, x ; lb, 0 ; k, 6 ;2b, 0 ; Linde lot 550 045, +). (a) 50, (b) 82 and (c) 87°C.SORPTION AND DIFFUSION OF n-C4H,,The equilibrium isotherms for n-butane in the four samples of 5A zeolite areshown in fig. 5. The isotherms for samples la and lb (65 % Ca2+) and for 2a and2b (> 95 % Ca2+) are consistent but there is a significant difference between samples1 and 2, presumably reflecting the difference in Ca2+ content.The isotherm forcommercial Linde 5A crystals is considerably lower.The analysis and interpretation of the uptake curves for samples 2a and 2b isstraightforward. Diffusion in these samples is sufficiently slow that thermal effectscan be neglected, at least in the early stages of the uptake, and the time constantsmay therefore be calculated, as for the diffusion of CF4, from the simple isothermaldiffusion model. Both the form of the uptake curves, illustrated in fig. 6, and thedifference in the time constants for the two different size fractions are consistent withthe simple diffusion model. Over the entire pressure range the time constants forthe smaller crystals are about four times as large as for the larger crystals so that thediffusivities for both size fractions are essentially the same as may be seen from fig.7.Comparisons are made at constant pressure rather than at constant sample loadin76 DIFFUSION IN 5A ZEOLITEto avoid any errors arising from differences in the isotherms. As has been previouslynoted for this system the concentration dependence of the diffusivity appears to bedue entirely to the non-linearity correction (d In p/d In c) and the corrected diffusi-vities (Do) are essentially constant.0 1 2 3 4 5 6 7 8 9 10 11 12 13 1 4 1 5 1 6l/t/s+FIG, 6.-Experimental uptake curves for n-butane in difference size fractions of 5A zeolite crystals(sample 2a and 2b). (a) 360K, pressure step 13-9Torr; (b) 323K, pressure step 7.5-5Torr.0, 55; A, 27.5 pm.The interpretation of the kinetic data for sample l a (34 pm) is similar. Uptakecurves measured under comparable conditions with two different sample quantitieswere essentially the same showing that uptake rates are controlled by intracrystallinephenomena rather than by bed diffinsion or external heat transfer limitations.Thevariation of time constants with butane concentration, illustrated in fig. 8, is similarto that observed for samples 2a and 2b. However, under comparable conditions,the diffusivities for sample l a are lower than those for 2a and 2b and this differenceappears to reflect a real difference in mobility, rather than a difference in the non-linearity correction factors, as may be seen from fig. 10 and table 3.The behaviour of the smaller (7.3 pm) crystals (lb) is more complicated.If theuptake curves for this sample are interpreted according to the isothermal diffusioH. YUCEL AND D. M. RUTHVEN(A) (B)..INLQ\ Eu7 10-2- - 1r/) --- na. W10-377- I-0 - - x x : XX - o( OX - x o x-1s - g os i o O Po xX - o xx a- - o xO X -I I I I I I l l 1 I I 1 I 1 1 1 1 I I I I l l l l l I I I I 1 1 1 100 - 0 0-0 o o0 0 00 x x r - XX0 XX00XXX 0 xX 0X XXX XXX Xt 1 I I I l l l l I I I I I I l l I I I I I l l l l I I 1 1 1 1 1 1 ,1 10 100 2 10 100p/TorrFIG. 7.-Variation of diffusional time constants and diffusivities for n-butane in 5A zeolite crystals[sample 2u (55 pm), x ; 2b (27.5 pm), 03. (A) 50 ; (B) 87°C.model one obtains time constants which show a much smaller increase with sorbateconcentration than for the other three zeolite samples under comparable conditions.At low pressures the time constants for sample l b (7.3 pm) are about twenty timeslarger than the values for sample l a (34 pm) and this difference is approximatelyconsistent with the square of the crystal radius, in accordance with the simple diffusionmodel.However, at higher pressures this ratio falls to about 5.0. Under theseconditions the initial uptake rates for the 7.3 pm sample are very rapid and the formof the uptake curves no longer conforms to the simple isothermal diffusion model.This anomaly can be quantitatively accounted for if thermal effects are considered.Non-isothermal sorption kinetics have been discussed in detail in a previouspublication in which the following expression for the uptake curve was derived interms of two dimensionless parameters a and p :1-co = c n= 1where qn is given by the roots of the equation :In eqn (1) mJm, represents the fractional approach to final equilibrium in responseto a small differential increase in sorbate pressure. The parameters a and p aredefined by a = (ha/pc,)/(D/r2) and p 3 (AH/cJ(dq*/dT),, where h is the external3P(q,cotq,-l) = 4:-a.(278 DIFFUSION IN 5A ZEOLITE1.0 5 10 50 1.0 5 10 50 100p/TorrFIG. 8.-Variation of diffusional time constants and diffusivities for n-butane in 5A zeolite crystalswith 65 % Ca2+. [la (34 pm), 12 mg sample wt., 0 ; 30 mg sample wt., x .lb (7.3 pm), fromisothermal model, sl ; from non-isothermal model, e.] (A) 50, (B) 82°C.TABLE 2.-PARAMETERS FOR NON-ISOTHERMAL ANALYSIS OF UPTAKE CURVES FOR BUTANE INSAMPLE 1b AT 50°Cpressure step/Torr(Dlr 2)/s-1(is0 t hermal values)62-4141-25.525.5-1515-85.4-3.73.7-2.92.9-2.52.5-2.0a-5.40.0340.0270.0220.020.01 70.01 60.01 30.0120.01 1P0.250.260.270.300.290.280.280.270.26U(D/r 2) Is-1(non-i so thermal)0.881.111.542.43 .O4.05.06.78.30.1 10.090.0660.0420.0330.020.0250.0150.012(ha/pcs = 0.1 s-l ; c, = 0.5 cal g-l K-lH . YUCEL AND D. M. RUTHVEN 79heat transfer coefficient, a is the external surface area per unit volume of the sample,pc, is the effective thermal capacity of the sample plus the containing pan, -AH isthe heat of adsorption and (aq*/aT), is the temperature derivative of the equilibriumadsorbed phase concentration. In order to apply this model to the analysis of theuptake curves for sample 16 we take (ha/pcJ = 0.10 s-l, as determined from experi-mental uptake curves, measured under similar conditions using small crystals of 13Xzeolite, in which diffusion is very rapid and heat transfer is rate controlling. Valuesof /? were calculated from the equilibrium isotherms with c,, the effective heat capacityof sample and pan, taken as 0.5 cal g-l K-l which is the value obtained from analysisof the thermally limited uptake curves for the 13X crystals.Using these values ofhafpc, and p the experimental uptake curves were matched to the theoretical non-isothermal curves to determine the diffusional time constants (D/r2).The time1.0; 2 aI40.10.020 4 8 12 16 20 24t l sFIG. 9.-Experimental uptake curve (0) for butane in sample lb (7.3 pm) at 50°C, pressure step15-9 Torr, compared with theoretical curve for non-isothermal sorption calculated from eqn (1)and (2) with cx = 2.4, B = 0.3, D/r2 = 0.042 s-I. Also shown are the theoretical curve for isothermalsorption with the same time constant (-), the theoretical curve for complete heat transfer controland the experimental (isothermal) curve (0) for sample la (34 pm) measured over a similar pressurestep (17.5-12.3 Torr) (D/r2 = 2.2 x s-l)80 DIFFUSION IN 5A ZEOLITEconstants derived in this way are shown in fig.8 and the relevant parameters axe givenin table 2. In fig. 9 the experimental uptake curve for one of these experiments iscompared with the theoretical curve calculated from eqn (1) and (2) (the non-isothermal model). The expected curve for isothermal diffusion with the same timeconstant is also indicated as well as the very much slower (isothermal) uptake curveobtained at similar sorbate concentration with the 34 pm sample (la). It is evidentthat the uptake rate for the 7.3 pm sample under these conditions is significantlyreduced by heat transfer limitation and the non-isothermal model provides a verygood representation of the experimental curve. Clearly, if uptake curves measuredunder non-isothermal conditions are interpreted according to the isothermal modelerroneously low values of D/r2 will result.The values of D/r2, for sample lb,derived from the non-isothermal analysis show the same concentration dependenceas was observed for the larger crystals. At low pressures the correction for thermaleffects is ininor but at high pressures the true values of DJr2 are about twice theapparent values derived on the basis of the isothermal assumption. The apparentdifferences in behaviour between samples l a and l b can thus be explained by theintrusion of thermal effects and diffusivities for the 7.3 pin crystals, calculated accord-ing to the non-isothermal model, are in good agreement with the values for the larger34 ,urn crystals.DIFFUSIONAL ACTIVATION ENERGIESArrhenius plots showing the temperature dependence of the corrected diffusivities(Do) are shown in fig.10 and the activation energies and pre-exponential factors forboth CF4 and n-C4H,, are given in table 3 together with the values obtained inearlier studies of diffusion in commercial Linde 5A crystal^.^^ The diffusivities forthe Linde crystals are very much smaller than the values for our own crystals andthis difference is of the same order as that noted for 4A zeolite in the preceding paper.We have confirmed by replicate experiments using different depths of crystal sampleand also by chromatographic measurements that uptake rates in the Linde sieve areindeed controlled by intracrystalline diffusion, so that this difference represents a realdifference in the diffusional properties of the crystals and cannot be explained byextraneous effects such as external heat or mass transfer limitations.Despite theTABLE 3 .-ARRHENIuS PARAMETERS GIVING TEMPERATURE DEPENDENCE OF LIMITING DIF-FUSIVITY Do ACCORDING TO Do = D* exp (--E/RT)D,/cm2 s-l E/kcal mol-l1.9 x 10-52 . 5 ~2a (55 ym)2b (27.5 ym) 6.69.151 (lot 550 045) .I la(34Dm) . 9~ 10-7 4.52a (".bm) } 3.1 x 10-6 n-C4Hlo 2b (27 5 pm) 4.6Linde (3:6 pm) 7.3 x 10-9 4.0 I (lot 550 045H. YUCEL AND D . M. RUTHVEN 81very large difference in diffusivities, the diffusional activation energies (for butane)are practically the same for all samples. The much lower diffusivity for the Lindecrystals is due to a lower pre-exponential factor as observed previously for N2 andC2H6 in the 4A zeolite.This suggests that the lower diffusivity is due to completeblockage of some of the zeolite windows in the Linde crystals rather than to partialblocking or changes in the effective dimensions of the windows. For CF4 the differ-ence in intrinsic diffusivities between the Linde crystals and our own sample 2 crystalsis even greater than for butane but in this case there appears also to be a difference inactivation energy.2.8 3.0 3.2 3.4 3.6 3.8 - 2.8 3.0 3.2 3.4 3.6 3.8103 KIT(A) CF4; (€3) n-C4HIo.FIG. 10.-Arrhenius plots showing temperature dependence of corrected diffusivity (Do). x ,2a (55 pm) ; 0, 2b (27.5 pm) ; 0, la (34 pm); B, l b (7.3 pm); - - -, Linde 5A (lot 550 045).CONCLUSIONSAnalysis of experimental uptake curves shows that in the larger crystals (la, 2aand 2b) the kinetics of sorption of both CF4 and n-C,H,, are controlled by intra-crystalline diffusion.The diffusional time constants show the ercpected variationwith the square of the crystal radius and there is no significant difference in diffusivitybetween different size fractions of similar zeolite crystals. The apparent anomal82 DIFFUSION IN 5A ZEOLITEin the behaviour of the smallest zeolite crystals (lb) can be satisfactorily explainedby the intrusion of heat transfer effects and when these effects are properly accountedfor the diffusivities derived from the uptake curves for this sample are found to beessentially the same as for the larger (34 pm) crystals of similar composition.Thereis, however, a considerable difference in intrinsic diffusivity between the two differentbatches of crystals. The batches have different Ca2+ contents but it has not beenestablished whether this difference is due directly to the difference in Ca2+ contentor to some other difference in sample preparation.To explain the large difference between diffusivities derived from n.m.r. and fromsorption rate measurements it has been suggested that uptake rates may be con-trolled by a surface barrier rather than by intracrystalline diffusion. In contrastwith the results of Karger et al., which show a strong increase in apparent diffusivitywith crystal size,2 the present results show no variation of diffusivity with crystal size,and therefore do not support the surface barrier hypothesis.An apparent variationof diffusivity with crystal size can arise from the intrusion of heat transfer resistanceand such effects, which become progressively more important as the crystal size isreduced, are not always easy to detect without very detailed experimentation. Anyexternal mass transfer resistance or other time delays will also become more significantas the crystal size is reduced and it seems possible that the anomalous behaviour pre-viously observed may be due to such effects. However, the present study was con-cerned mainly with larger zeolite crystals (7.3-55 pm) and one cannot completelyexclude the possibility that surface effects may be more important in the smallercrystals studied by Karger et a2.l'Most of the earlier studies of uptake kinetics in the A zeolites, both in this labora-tory and elsewhere, were carried out on commercial Linde crystals whereas the n.m.r.measurements, which require in general larger crystals, have been carried out ex-clusively on laboratory synthesized samples.The present results indicate thatdiffusivities for the laboratory synthesized crystals are very much higher than for thecommercial Linde crystals. For butane at 25°C in the fastest diffusing sample(sample 2) the present results suggest a corrected diffusivity of z 1.3 x cm2 s-lcompared with the value of w 4 x cm2 s-1 estimated from n.m.r. relaxationmeasurements with the jump distance taken as 12.3 r f .This difference is verymuch smaller than was formerly supposed on the basis of comparisons with the uptakedata for Linde crystals.2* A difference of this order could well be due to differencesin the zeolite samples. In the comparison between sorption and n.m.r. diffusivitiesthe results for CH4-4A and butane-5A appear to point to opposite conclusions sincein the case of CH4-4A the discrepancy appears to be too large to explain simply bydifferences in the zeolite sample whereas for butane-5A this seems possible. However,the present results show clearly that the differences in diffusivity between differentsamples sf both 4A and 5A zeolites are very much greater than was formerly supposedand it is evident that the comparison between n.m.r. and sorption diffusivities canonly be resolved by comparing identical samples.We thank Jar. J. Karger (K.M.U., Leipzig) for providing us with advance copiesof ref. (1) and (2) and for helpful and informative discussions. The type A zeolitecrystals used in these studies were synthesized in these laboratories by Dr. W. I.Derrah according to Charnell's method. loJ. Karger, J. Caro and M. Bulow, 2. Chern. 1976,16, 331.J. Karger and J. Caro, J.C.S. Faraday I, 1977, 73, 1363.H. Yucel and D. M. Ruthven, J.C.S. F'raday I, 1980,76,71H. YUCEL AND D. M. RUTHVEN 83H. Yucel, Ph.D. Thesis (University of New Brunswick, Fredericton, N.B., Canada, 1978).D. M. Ruthven and R. I. Derrah, J.C.S. Faraduy I, 1972, 68,2332.D. M. Ruthven, R. I. Derrah and K. F. Loughlin, Canad. J. Chem., 1973,51, 3514. ’ Lap-Keung Lee and D. M. Ruthven, J.C.S. Favaday I, 1979,75,2406. * L. Labisch, R. Schollner, D. Michel, H. Rossiger and H. Pfeifer, 2. phys. Chem. (Leezig),1974,255, 581.D. M. Ruthven, Amer. Chem. SOC. Symp. Series, 1977, 40,230.l o J. F. Charnell, J. Crystal Gruwth, 1971, 8,291.(PAPER (9/107

ISSN:0300-9599    

DOI:10.1039/F19807600071

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Favaday I, 1980,76, S4-91Cracking of (5-13C)-n-Nonane with Quartz Wool,Silica-Alumina and Type Y ZeoliteBY THOMAS J. WEEKS, JR,? IRWIN R. LADD AND ANTHONY P. BOLTON"Union Carbide Corporation, Tarrytown Technical Center,Tarrytown, New York 10591, U.S.A.Received 30th January, 1979The cracking mechanism of (5-' 3C)-n-nonane has been studied over quartz wool, silica-aluminaand a type Y zeolite. The products observed at a reaction temperature of 510°C over quartz woolagree reasonably well with the currently accepted mechanism of free radical cracking. Reactionwith silica-alumina at 500°C and zeolite at 230°C results in a 13C labelled product distribution whichagrees with neither a thermal cracking mechanism nor the currently accepted mechanism of /%scissionof carbonium ion intermediates.Rather, the data suggest that the product distribution is a resultof the temperature-dependent random desorption and cracking of a complex polymeric precursor.The cracking of hydrocarbons over zeolite catalysts is of considerable comniercialimportance and has consequently been extensively studied. The results from thecracking of pure components have usually been interpreted in terms of a p-scissionmechanism involving carbonium ion formation, primary cracking and secondary~racking.l-~ However, some recent data on the cracking of (3-1 3C)-n-pentaneshowed that the 13C labelling of the cracked products, particularly propane, ap-proaches that of a totally random di~tribution.~ The complete redistribution of "Cand 13C in the products from the cracking of labelled hydrocarbons over H-mordenite has also been reported by Gault.6 On the basis of these data, it wasconcluded that the cracked products are formed from the breakdown of a sorbedcomplex polymeric material.However, pentanes and hexanes " do not containenough carbon atoms to allow the most probable carbonium ion cracking routes tomanifest themselves by the lowest energy pathways and axe therefore, in a sense,special cases ".' The molecule that is classically selected to illustrate the carboniumion mechanism of catalytic cracking is 2,2,4-trimethylpentane. Indeed, the crackedproducts are, as would be expected, isobutane and the butenes.* However, sincethere is but a limited number of ways that this particular molecule can undergoscission, studies using this molecule might inherently prejudice an evaluation of thecracking mechanism, A more satisfactory evaluation should be offered by studyinga large paraffin that possesses the possibility of cracking in a variety of ways.Thusthe paraffin n-nonane was chosen.As well as studying the cracking of n-nonane over a zeolite catalyst, additionalexperiments were carried out using silica-alumina and quartz wool. Possiblesimilarities or differences between the products from these materials should provideadditional insight into the mechanism of catalytic cracking over a zeolite.EXPERIMENTALMATERIALSThe zeolite was an ammonium-exchanged, hydrothermally stable Linde type Y molecularsieve (LXY-82).The zeolite, a silica-alumina cracking catalyst (Durabead-1 from MobilOil) and quartz wool had the following analysis :847 Present address : Ashland Chemical Company, P.O. Box 2219, Columbus, Ohio, U.S.AT. J . WEEKS, JR, I . R . LADD AND A . P. BOLTON 85quartz wool silica-alumina zeoliteA1203 /wt % 0 11.1 22.8SiOz /wt % 100 89.0 72.2NazO /wt % 0 < 0.1 0.2(NH4)20 /wt % 0 0 4.0surface area/m2 g-1 1.2 309 770~(5-13C)-n-nonane was obtained from Merck, Sharpe and Dohme of Canada and was 95 %enriched. Non-labelled n-nonane was from Matheson, Coleman and Bell and was usedwithout further purification ; chromatographic analysis showed it to contain 99.6 %n-nonane with trace amounts of other C9 isomers.PROCEDUREThe experiments were conducted in a 130cm3 glass reactor.The zeolite and quartzwool were activated in vacuum at 500°C in the reactor for 4 h. The silica-alumina wasactivated in steam at 550°C for 4 h followed by vacuum activation at 500°C for 2.5 h in thereactor. Because of the high cracking activity of the zeolite, less of this catalyst was usedin the experiments than the other two materials. After activation, the appropriate reactionconditions were adjusted to obtain the required conversions and the n-nonane was introducedinto the system. The following reaction conditions were used :quartz wool silica-alumina zeolitewt catalyst/g 1.037 1.006 0.100wt n-nonane/g 0.108 0.082 0.080reaction conditions temp/"C 510 500 230sampling time/min 5, 15 2.5, 7, 15 2.5,7, 15initial pressure/Torr 150 100 10010cm3 samples were taken at the indicated intervals and expanded into 50 or 500cm3vessels.Samples of the products were injected into an integrated gas chromatograph-mass spectrometer. The mass spectrometer was a JEOL JMS-D100 with a Texas Instru-ments 980B computer and Diablo disc. The mass spectrometer was operated at 17eVfor the silica-alumina and quartz experiments and 1OeV for the zeolite experiments. A20 ft, Q in. n-octane Porasil C 80/lOO chromatographic column was used in the silica-alumina and quartz wool experiments and a 20 ft, -$ in. 10 % OV-101 SO/lOO Supelcoportcolumn in the zeolite experiments. The mass spectrometer was repeatedly scanned at9 s intervals at a 20 s scan speed for the full range. The actual scan time was 5-6 s from26 to 170 m/z.Difficulty was experienced insufficiently separating by chromatography the relatively large number of products from thesilica-alumina catalyst for subsequent mass spectral analysis. Consequently, 3C labellingdata could not be obtained for all of these products.Beam conditions were 3 kV and 100 PA.RESULTSProduct distribution obtained by chromatographic analyses is shown in table 1.The experimental apparatus and conditions were not optimized to yield quantitativeconversion data, but rather to obtain precise labelling information. The 3Cdistribution and fragmentation patterns of the starting material, n-nonane, arepresented in table 2. Mass spectrographic analyses of the unreacted n-nonane inthe reaction products showed the labelling to be identical to that in the startingmaterial.The mass spectrographic data for the reaction products from the thre86 CRACKING OF LABELLED n-NONANE WITH VARIOUS CATALYSTSTABLE 1 .-CHROMATOGRAPHIC ANALYSES OF PRODUCTScat a1 yst quartz wool silica-alumina zeolitesampling timelmin 5 15 2.5 15 2.5 15product product distribution/mol %1.84.13.84.00.31.80.20.00.00.01.40.00.00.01.20.90.380.215.411.47.46.70.52.60.00.00.00.02.00.60.00.00.50.00.051.10.02.65.514.13.62.44.22.74.41.90.81.83.20.00.00.00.051 .O0.020.28.13 .O11.92.63.33.614.44.80.11 .o2.50.00.00.00.017.60.00.00.00.02.40.00.00.09.62.80.00.010.40.90.00.00.071.20.00.00.00.06.80.08.00.028.35.50.00.024.81.60.00.00.027.7catalysts me summarized in tables 3, 4 and 5.These data have been corrected fornaturally occurring isotopes and fragmentation observed in the non-labelled expek-ments. Calculations of isotopic labels was carried out by using the Mass SpectralSearch System (EPA) program LABDET. Although analyses were carried out atdifferent reaction times, no differences were observed in product labelling and henceonly those data from the 2.5 and 5 min samples are presented. These data are anaverage of 4 scans per peak from duplicate experiments. The precision of massTABLE MAS MASS SPECTROGRAPHIC ANALYSIS OF (5-1 3C)-n-NONANEion mlz mol %M+ 129128M-29+ 10099M-43+ 8685M-57+ 7271946937919891113C enrichment 10.4 T.J . WEEKS, JR, I . R . LADD AND A . P . BOLTON 87spectral measurement was estimated by calculating the standard deviation fromseven measurements of the M-29f ion of nonane recovered from the 5 min samplefrom the quartz wool reaction. The standard deviation for m/z = 100 and 99 were1.5 and 1.0, respectively. The tables also include the calculated 3C label distributionfrom two possible mechanisms ; one resulting from an intermolecular randomscrambling process in which the distribution is derived from the binomial expansion(a+ b)" where a, b axe the percentages of labelled and non-labelled carbon atoms,respectively, and n is the number of carbon atoms in the molecule ; the other from asimple unimolecular scission mechanism.Attempts to obtain quantitative informa-tion on the methane labelling from the quartz experiment were unsuccessful becauseof the small sample size. Qualitative results showed no labelled methane was presentafter 5 min.DISCUSSIONThe product distributions obtained from the cracking of n-nonane over the threecatalysts are shown in table 1. These data show the quartz wool to promote freeradical cracking which results in the formation of olefins together with quantities ofmethane and ethane.The zeolite yields a completely saturated product, principally isobutane andisopentane, which, incidentally, is very similar to that obtained by reacting an olefinover the zeolite at a comparable temperature. 9-1 The silica-alumina catalyst, onthe other hand, gives rise to a product more similar to that of the zeolite than thequartz wool but containing a substantial amount of olefins.The difference in productdistribution between the zeolite and silica-alumina is probably a reflection of thedifferent operating temperatures required to achieve reaction and is consistent withprevious studies.Mass spectrographic analyses of the starting n-nonane are shown in table 2.These data show not only the position of the label in this material but also the frag-mentation of a luge n-paraffin in a spectrograph. No rearrangement is observedupon loss of an ethyl, propyl or butyl group. The fragmentation patterns clearlyshow that the starting material is labelled in the 5-position, since the extent of labellingchanges little upon loss of ethyl, propyl and butyl fragments.As in a previous studyusing n-pentane, the mass spectrographic data of the unreacted n-nonane in theproduct was indistinguishable from the starting material.5 Thus the unreactednonane had not participated in any reactions on the zeolite surface.QUARTZ WOOL PRODUCTExamination of the mass spectrographic data from the quartz wool experimentshows that the butene, pentene and hexene are all produced from a simple scissionreaction. A radical chain mechanism for thermal cracking of paraffis was firstproposed by Kossiakoff and Rice.12 The initial propagation step is the abstractionof hydrogen from the paraffin to form a radical, followed by a @cission of the radicalto form an olefin and a smaller radical.A sequence of /?-scissions can occur untilsome small radical is formed for which /?-scission is replaced by hydrogen abstractionto yield a paraflin. The product distribution in this study is consistent with theproposed mechanism and similar to that reported for the thermal cracking of theisomeric hexanes.13 The formation of a C4 hydrocarbon by @-scission from an-nonane radical labelled in the 5-position would require the product to be m-labelled. The data in table 3 show this to be the case. Conversely, the formationof C5 and C6 hydrocarbons by p-scission would require both products to be essentiall88 CRACKING OF LABELLED n-NONANE WITH VARIOUS CATALYSTScompletely labelled.Again, the data in table 3 confirm the scission mechanism.The mass spectrometric fragmentation data for loss of a methyl group from the C5and C6 products show as expected the former to be labelled at a terminal carbon atomand the latter at a non-terminal carbon atom. The sequential formation of ethyleneaccording to the chain mechanism allows for this product to be singly labelled as thedata in table 3 show. If propylene were only formed by the initial scission of anonane radical, it would not be labelled. This was not observed experimentally.TABLE 3 .-MASS SPECTROGRAPHIC ANALYSES OF PRODUCTS FROM QUARTZ WOOLno. labelled isotopic calculated distribution/ %product carbons species/ % random unimolecularC2H4 M+ 21002278119800010021001s8211980001002100227800100325722100010053064001001-CSHlo M' 21008911834580946M-15 mlz 561-C6H12 M+10604021009281136520946M-15 m/z 70 108317However, product distribution data show that propylene is present in the productin a greater quantity than hexene, rather than in an equivalent quantity.This mustindicate that propylene is also derived from further sequential scissions of largerlabelled radicals. This would result in the single labelling of the propylene and beconsistent with the data in table 3. A similar argument apparently holds for thepresence of labelled ethane. The data obtained on the thermal cracking of paraffinshaving more than six carbon atoms are difficult to interpret and are open to somea.mbiguity.14 Thus, the labelling data on propylene and ethane may not be asinconsistent as they might at first appearT .J . WEEKS, JR, I . R . L A D D A N D A . P. BOLTON 89S I LI C A-A LUMI N A PRODUCTNot unexpectedly, both the product distribution and the mass spectrographicanalyses of the products confirm that the cracking mechanism over silica-alumina iscompletely different from that taking place over quartz wool. However, it is readilyapparent from the spectrographic data that, contrary to current opinion, the productscannot be produced by a simple /?-scission mechanism involving carbonium ionformation since the labelling data for the propylene, propane and butylene axe inclose agreement in every instance with that calculated for random distribution.This conclusion is supported by the carbon enrichment data which show that theisotopic content of the products is equivalent to that of the starting material. Thus,as the significant amount of double labelling in the products indicates, the crackedproduct must be derived from a completely random intermolecular mechanism.Incontrast to the singly labelled propylene in the quartz wool product, the propylenein the silica-alumina product is randomly labelled. The latter must result fromsynthesis via a randomly labelled polymeric precursor rather than from a simplescission of a radical or olefin.That the unreacted nonane present in the reactionproducts has the identical isotopic distribution to the starting material argues againstthe possibility of subsequent scrambling of primary paraffinic products. Even ifsome of the products were generated by a secondary reaction with the catalyst, theisotopic labelling data would not be so completely random. It is remarkable thatat similar reaction temperatures the quartz wool and the silica-alumina give rise tosuch different mechanisms. In view of the high surface area of the silica-aluminacatalyst, one might have expected at least some of the olefins to be produced by afree radical mechanism. However, the labelling data are particularly definitive onthis point. Although a random intermolecular mechanism is contrary to thecurrently accepted mechanism of catalytic cracking involving the B-scission of acarbonium ion, the data supporting the proposed mechanism are self-consistent andparticularly explicit and, moreover, not totally unexpected in view of a previousstudy on the cracking of n-~entane.~ The conclusion from the previous study mayalso be invoked to explain the carbon enrichment and labelling data of the silica-alumina products ; that they axe derived from a complex polymeric precursor on thecatalyst which bears no resemblance to the starting material.TABLE 4.-MASS SPECTROGRAPHIC ANALYSES OF PRODUCTS FROM SILICA-ALUMINAno. labelled isotopic 13C calculated distribution/ %product carbons species/ % enrichment/ % random unimo1ecula.rC3Htj M+ 210CjHs M+ 2101-C4Hs M+ 21022969426704326411.0 3257211.3 3257210.0 530640010000100001090 CRACKING OF LABELLED n-NONANE WITH VARIOUS CATALYSTSZEOLITE PRODUCTThe labelling data of the products from the zeolite cracking experiment are moredifficult to explain than those from the quartz or silica-alumina experiments.Theproducts have the same carbon enrichment as the starting material which precludesa simple unimolecular mechanism. However, only the labelling data of isobutaneare consistent with random distribution, those from the other products being neitherunimolecular nor random intermolecular.TABLE 5.-MASS SPECTROGRAPI-IIC ANALYSES OF PRODUCTS FROM ZEOLITEno.labelled isotopic I3C calculated distribution/ %product carbons species/ % enrichment/ % random unimolecularC&j M+ 210i-C4H10 M+ 210n-C4Hlo M+ 210i-C5H12 M+- 210n-C5HI2 M- 2100.53664334630.54257347503465012.3 3257210.0 5306410.8 5306410.6 8345810.4 8345800100001000010009460946The isotopic scrambling observed in the products from both the zeolite and silica-alumina cannot be explained in terms of subsequent interaction of either saturatedor unsaturated products from a direct scission mechanism. The cracked productsfrom a zeolite at M 200°C are characterized by the total absence of olefins and tosatisfy hydrogen stoichiometry it could be assumed that olefins are irreversiblyadsorbed on the zeolite and undergo further reaction.Thus, one may argue thatthe saturated products from the zeolite are derived from both the cracking reactionand a subsequent olefin condensation-polymerization reaction. This would yielda labelling distribution intermediate to that of random scrambling and simple uni-molecular scission. However, the carbon enrichment data of the products do notsupport this explanation. For example, if a portion of the isobutane were derivedfrom a simple scission, this material would contain no 13C and, therefore, wouldhave zero enrichment. The extent to which the total isobutane incorporates someisobutane from simple scission would reduce the overall enrichment of the productisobutane to considerably less than that of the starting material, i.e., 10.4 %.Infact, this is not the case since a value of 10.0 % was observed. Thus the primarT. J . WEEKS, JR, I . R. LADD AND A. P. BOLTON 91products from catalytic cracking must be formed directly from a sorbed polymericintermediate and not as a result of secondary reactions.It may be significant that the redistribution of 12C and 13C in the products fromthe zeolite is not as complete as that taking place over silica-alumina at the higherreaction temperature. This observation might indicate that both the productdistribution and the extent of 12C and 13C redistribution are more a function ofreaction temperature than the particular catalyst system. It has been suggestedthat the principal difference in products between amorphous and crystalline catalystsis due to the different temperature ranges over which these catalysts 0perate.l Theseinvestigators showed that at a reaction temperature where both catalysts could bedirectly compared the cracked products are remarkably similar.The suggestionthat cracked product distribution is primarily dictated by reaction temperatureimplies that a prerequisite for cracking activity is the possession of a pore system toact as a " pot " in which the reactants axe converted into a complex polymericprecursor and from which they randomly desorb as products characteristic of thattemperature.CONCLUSIONWe conclude from the labelling data that the results from the thermal crackingof n-nonane over quartz wool are in reasonable agreement with those from previousstudies.However, the labelling data from the silica-alumina experiments indicatethat the products are derived from an intermediate polymeric precursor and cannotbe explained in terms of p-scission of carbonium ion intermediates. The labeldistribution results from the zeolite study are less explicit, but the 13C enrichmentdata from the zeolite experiments together with both the labelling and I3C enrichmentdata from the silica-alumina study raise considerable doubts as to the validity of thecurrently accepted mechanism of catalytic cracking.We thank Dr. M. L. Poutsma for fruitful discussions on reaction mechanismsand Mr. P. W. Shafer for many stimulating talks.J. N. Miale, N. Y. Chen and P. H. Weisz, J. Catalysis, 1966, 6, 279.H. A. Benesi, J. Catalysis, 1967, 8, 368.P. B. Venuto and E. T. Habib, catalysis Rev. Sci. Eng., 1978, 18, 1.A. P. Bolton, I. R. Ladd and T. J. Weeks, Proc. VI Int. Congr. Catalysis, London, 1976, p. 316.F. G. Gault, Proc. V.. Int. Congr. Catalysis, London, 1976, p. 321. ' M. L. Poutsma, Zeolite Chemistry and Catalysis, ed. by J. A. Rabo, A.C.S. Monograph 171,(Amer. Chem. SOC., 1976), vol. 8, p. 506. * D. Barthomeuf and R. Beaumont, J. Catalysis, 1973, 30,228.T. J. Weeks and A. P. Bolton, J.C.S. Faraday I, 1975, 70, 1676.lo T. J. Weeks, C. L. Angell, I. R. Ladd and A. P. Bolton, J. Catalysis, 1974, 33, 256.l1 P. B. Venuto, L. A. Hamilton and P. S. Landis, J. Catalysis, 1966,44, 589.l2 A. Kossiakoff and F. 0. Rice, J. Amer. Chem. Soc., 1943,65,590.l3 J. A. Rabo and M. L. Poutsma, Molecular Sieve Zeolites-II, Adu. Chem. Series No. I02 (Amer.l4 D. A. Leathard and J, H. Purvell, Ann. Rev. Phys. Chem., 1970,21, 197.* S. E. Tung and E. J. Mininch, J. Catalysis, 1968, 10,166, 175.Chem. SOC., 1971, p. 284).(PAPER 9/148

ISSN:0300-9599    

DOI:10.1039/F19807600084

出版商:RSC    

年代:1980

数据来源: RSC

摘要:

J.C.S. Faraday I, 1980, 76,92-100Catalytic Conversion of AlcoholsPart lO.-T-fluence of Pretreatment on the Selectivity of MgO and CaOBY BURTRON H. DAVIS?Potomac State College of West Virginia University,Keyser, West Virginia 26726, U. S . A.Received 31st January, 1979With both CaO and MgO catalysts, the hydrogen pretreated material is a selective dehydroge-nation catalyst while the oxygen pretreated material has about the same activity for both dehydro-genation and dehydration. Initially the air (or oxygen) pretreated MgO sample produces an alkenedistribution from 2-01s that resembles that obtained with alumina ; as the reaction temperature isincreased a similar alkene distribution, different from the equilibrium value, is obtained with bothpretreatments. The three temperatures used with CaO yield an alkene distribution, with either pre-treatment, that resembles the highest temperature run with MgO. Pure cis-2- or trans-2-methylcyclo-hexanol undergoes extensive cis-trans isomerization ; the different alkene distributions from the twoalcohols suggest that a trans elimination pathway contributes to the dehydration mechanism.Group I1 metals form the most basic oxides of the group A elements that are notsoluble in water.A knowledge of the activity and selectivity of these group IIAoxides is necessary if we are to obtain comprehensive ideas and theories for thecatalytic action of metal oxides for the conversion of alcohols.Studies with these oxides suggest that the number of basic sites depends on thecalcination temperature; the maximum number appears to be present in a materialcalcined at 775-825 K.lm3 These basic sites may determine the catalytic ~electivity.~Most studies of alcohol conversion over MgO and CaO indicate that both oxides arevery selective dehydrogenation cataly~ts.~-l Only those materials that are con-taminated with COz (or carbonate) or which result from an incomplete decompositionof the carbonate appear to be active for alcohol dehydrati~n.~.~~ Propan-2-01 hasbeen employed for the majority of the studies of alcohol conversion but it can onlyform one dehydration product.In a study with a higher carbon number alcohol,butan-2-01, it was observed that, for the small amount of dehydration, the terminalalkene was greatly favoured.In another study, Canesson and Blanchard reportedthat the selectivity for hex-1-ene from hexan-2-01 paralleled the base strength reportedby Iisuka et aL3 Two recent studies have employed the microreactor technique(pulse method) to obtain the activity and selectivity for butan-2-01 conversion.Vinek et aZ.14 found that the dehydrogenation selectivity depended strongly upon thestorage time and calcination temperature; the increase in hydroxide layer anddecreasing basicity with storage changed the selectivity from dehydrogenation intodehydration. Thomke l 5 reported that the dehydration selectivity, at 50 % totalconversion, was 8 % for MgO and 70 % for CaO. The but-1-ene selectivity withMgO changed from =SO % at 673 K to 50 % at 773 K but with CaO the selectivityonly varied from 20 to 30 %.7 Present address : Kentucky Centre for Energy Research Laboratory, University of Kentucky,P.O.Box 13015, Lexington, Kentucky 40583, USA.9B. H. DAVIS 93These limited studies suggest that group IIA metal oxides may resemble otherAlumina has traditionally been viewed as a very selective dehydration catalyst.’selective a-olefin forming catalysts such as thoria.However, pretreatment in oxygen may impart a dehydrogenation activity that is atleast as great as the dehydration activity.17 Even though the pretreatment may playa major role in determining the activity and selectivity, it has not received muchattention for most of the metal oxide catalysts.The present investigation defined the influence of the hydrogen or oxygen pre-treatment on the dehydrogenation activity and the alkene selectivity of CaO and MgO.Hopefully, a unified picture of the catalytic selectivity will emerge as more oxides arestudied.EXPERIMENTALCATALYSTSMagnesium oxide was suspended in distilled water and heated near the boiling point for6 h.The solid was collected, dried at 390 K in air and then heated in air for G h at 1270 K.The CaO used for the runs with octan-2-01 [footnote (c), tables 1 and 21 was prepared byheating Fisher calcium hydroxide in situ in flowing oxygen or hydrogen to 825 K and holdingit at this temperature in the flowing gas. The CaO used for the other runs was prepared byadding ammonium carbonate to a calcium nitrate solution. The resulting calcium carbonatewas collected by filtration, dried at 390 K and then calcined in air at 875 K for four days.PROCEDUREA syringe pump was used to charge the reactant to a fixed bed glass reactor fitted with athermowell.The liquid products, after passing through a water condenser, were collectedat time intervals. The liquid was analysed for conversion using temperature programmedg.c. with a Carbowax 20M column. Alkenes were analysed using g.c. with the columnappropriate for the particular alkene mixture : UC-W, Carbowax 20M or P,P’-oxydipropio-nitrile. cis- And trans-2-methylcyclohexanol content was determined by g.c. with a di-glycerol column.Initially, the catalyst, in powder form, was pretreated in the reactor ; thereafter, a standardregeneration was used prior to the next pretreatment in air, hydrogen or oxygen.Theregeneration consisted of stopping the reactant flow and cooling the catalyst from the runtemperature to near room temperature. A flow of air was passed over the catalyst while itwas slowly heated (for 20-30 min) to 525 K and held at this temperature for M 3 h. Thetemperature was then increased to 790-825 K and held at this temperature for 3-6 h. Foran air pretreatment, the catalyst was then cooled to the reaction temperature in flowing air.For the other pretreatments the air flow was replaced by the pretreatment gas flow and thecatalyst was heated at 790-825 K for 3-6 h. In all cases, the catalyst was cooled to the re-action temperature in the pretreatment gas flow.RESULTSThe conversion data in fig.1 for 4-methylpentan-2-01 over MgO clearly show theinfluence of pretreatment on the dehydration m d dehydrogenation activity. Thecatalyst was about equally active for dehydration and dehydrogenation following anair pretreatment at 775 K [fig. l(a)]. After completing the run represented in fig. l(a),the catalyst was regenerated by the standad procedure and then pretreated withflowing hydrogen for 4 h. The sample now had about the same dehydration activitybut the dehydrogenation activity was two to three times greater than that of the airpretreated sample [fig. l(b)]. The decrease in dehydrogenation activity with time-on-stream for the air pretreated sample is not representative ; in most cases the activitychanged much more slowly (e.g., see the pentan-2-01 results in table 1).In comparin94 CATALYTIC CONVERSION OF ALCOHOLSthe data in table 1 it should be noted that the conversion range represents the high andlow conversion for the 4-6 samples collected during the duration of the run SO thatthere was little change in the activity during a run. Following the run fur fig. l(b),the sample was again given the standard air regeneration and air pretreatment ; thedehydrogenation and dehydration activity of the catalyst repeated the original airpretreatment [compare fig. l(a) and (c)].air-613K-eneI I I I I I I I 1 1 1100 200 300 400 100 200 300 400time/minFIG. 1 .-Influence of pretreatment on the conversion of 4-methylpentan-2-01 to methylpentenes and4-methylpentan-2-one over a magnesium oxide catalyst.TABLE DE DEHYDRATION SELECTIVITY FOR THE CONVERSION OF ALCOHOLS OVER MAGNESIUMAND CALCIUM OXIDE~ ~ ~length of conversionb dehydrationbalcohol pretreatment LHSV T/K runlmin range/mol % selectivityoct an-2-01pentan-2-01 air 0.130.260.51H2 0.130.260.51air 0.260.260.510.511.03H2 0.260.511.99590 360613 180633 105588 335608 160641 120523 230578 380598 325618 240633 175588 365608 29063 3 7029-2824-2425-2238-3939-4045-498-1015-1 812-1516-2317-2226-2727-3023-240.55-0.580.47-0.550.3 5-0.3 80.16-0.200.15-0.170.08-0.090.97-0.980.88-0.900.88-0.890.68-0.860.62-0.710.29-a. 3 10.24-8.250.1 5-0.1B.H.DAVIS 95length of conversionb dehydrationbalcohol pretreatment LHSV T/K run/min range/mol % selectivity4met hyl-pent an-2-01(cis + trans)-2-methylcyclo-hexanoltrans-2-methyl-cyclohexanolpentan-2-01octan-2-014met hyl-pentan-2-01(cis+ trans>-2-methycyclo-hexanoltrans-2-met hyl-cydo hexanolcis-2-met hyl-cyclohexanolairH2airairH2airH2air0 2332airH2airH2H2airJ32air0.13 587 2700.26 613 4800.51' 638 2050.13 589 3750.26 613 3400.51' 633 1950.51' 633 1300.13 589 4950.28 617 1700.51 633 2950.13 593 3700.26 613 4150.51 638 1300.26 613 1650.26 608 190CaO0.130.260.510.250.250.130.260.260.250.130.610.260.260.510.130.260.510.260.260.2660362364356356359361 363355860363359161864360362364362362362329520513043530538031030027036590305330245360370175808590-19-2419-214332-4238-401825-3 123-2516-2224-2541-4830-321 6-2229-3222-3518-2918-3221-4412-1628-4422-4328-5011-1430-5210-2915-2918-2528-3322-2 81 1-2421-331 1-2439-4527-420.58-0.730.46-0.620.43-0.520.22-0.250.13-0.150.83-0.870.71-0.740.62-0.630.58-0.620.20-0.260.29-0.370.8 1-0.860.28-0.290.290.600.54-0.550.36-0.480.45-0.520.11-0.140.47-0.500.36-0.620.46-0.630.09-0.170.43-0.620.3 5-0.740.07-0.140.18-0.240.17-0.210.52-0.660.58-0.690.55-0.630.52-0.600.3 3 -0.5 60.78-0.790.37-0.57~ ~ ~-~ ~a Liquid hourly space velocity (cm3 reactant per cm3 catalyst per h).b Values given are theextremes in conversion and selectivity for the 4-6 samples collected during the course of the run.C Runs with pretreatments of air, hydrogen and air (with regenerations between the runs) in succession.d Calcium hydroxide heated to 500 "C in flowing oxygen. e Sample given standard regenerationfollowed by hydrogen reduction. f Same as (d) except heated in flowing hydrogen96 CATALYTIC CONVERSION OF ALCOHOLSTABLE 2.-ALKENE SELECTIVITY FROM THE CONVERSION OF 2-OLS WITH CALCIUM AND MAGNES-IUM OXIDESalkene/mol %time conversionalcohol pretreatment LHSV T/K /min /mol % 1- trans-2- cis-2-pentan-2-01 air 0.130.260.51H2 0.130.260.51octan-2-01 H2 0.26pentan-2-01 air 0.130.260.51oc tan-2-01 0 2 0.13H2 0.13588 95205280360613 180633 105588 335608 160643 120608 215290CaO293230302422384045323022 24 5326 25 4924 31 4523 34 4322 32 4622 35 4316 55 2924 43 3329 34 3725 48 2728 42 30603 195295623 205643 130563 435563 30525221818231327 37 3626 36 3829 35 3629 35 3634 31 3534 32 34The selectivities for the conversion of pentan-2-01 and 4-methylpentan-2-01 overMgO are very similar for each temperature and pretreatment.Octan-2-01 and2-methylcyclohexanol also have similar selectivities at each temperature and pre-treatment ; however, MgO appears to be more selective for the dehydration of thesehigher molecular weight alcohols than for the pentanols.The CaO results in table 1 are similar to the corresponding runs using MgO andthe dehydration selectivity for each alcohol corresponds closely to that obtained withMgO.However, the conversion varies over a much wider range during the course of arun showing that CaO ages more rapidly than does MgO. The two materials appearto have a similar initial activity when compared on an equal catalyst weight basis. TheB.E.T. surface area of the catalyst was determined after use and storage for a monthor more; it is unlikely that the area measured is the same as it would be if it wasmeasured during use as a catalyst. The area, after evacuation at 473 K, was :MgO, 56 m2 8-l; CaO, 4.2 m2 g-l.This indicates that CaO, on an equal area basis,may be even more active than the MgO catalyst.With MgO the dehydration selectivity decreased with increasing temperature forboth pretreatments ; this trend was not as clear-cut with CaO.The alkene selectivity may also depend on the pretreatment. At 591 K, hydrogenpretreated MgO produced an alkene distribution that was constant with time and wasessentially the equilibrium distribution (fig. 2). The air pretreated sample yielded analkene distribution with cis-pent-2-ene as the major product ; as the reaction progressedthe alkene selectivity changed to produce more of the trans-2-isomer at the expense oB. H. DAVIS c- 6050X 40-E8 30-40\4 cd2010----air, 591 K pentan-2-01.H, 591 K1 I I 1 I 1 I I I 1 1r b A - I0 --- 1 I 197time/minFIG. 2.-Comparison of the alkene distribution from the conversion of pentan-2-01 over air andhydrogen pretreated magnesium oxide ; @, I-pentene ; A, trans-pent-Z-ene ; M, cis-pent-2-ene [opensymbols represent the equilibrium n-pentene composition calculated from data in ref. (26)].600 625 575 600 625 575 600 625FIG. 3.-AIkene composition from the conversion of pentan-2-01 over hydrogen and oxygen pre-treated magnesium oxide catalyst [(-) represents the equilibrium value calculated using datafrom ref. (26) ; the open symbols are for the hydrogen pretreated sample ; solid symbols are for theair pretreated sample].11-98 CATALYTIC CONVERSION OF ALCOHOLSthe cis-2-isomer. Initially, the alkene selectivity of MgO resembled that of alumina.l*Thus, the alkene selectivity of the air pretreated sample changed with time-on-streameven though the dehydration selectivity remained nearly constant with time. Thealkene distribution changed with increasing temperature to approach an alkenecomposition that was the same for both pretreatments ; this composition differs fromthe equilibrium value (fig.3). The alkene distribution from pentan-2-01 was represen-tative of the results obtained with MgO with the other acyclic 2-01s.CaO yielded essentially the same alkene distribution with the hydrogen or theoxygen pretreated material with octan-2-01 and 4-methylpentan-2-01. 0cta.n-2-01produced about equal amounts of the three alkenes allowed by /?-elimination.Thealkene distributions obtained with pentan-2-01 and 4-methylpentan-2-01 did notappear to change with temperature as was the case with MgO; the distribution withCaO was approximately the one that was obtained at the highest temperature usedwith the MgO catalyst.Calcium and magnesium oxide catalysts were similar for the conversion of 2-methylcyclohexanol. CaO may have been slightly more selective for dehydrationthan MgO was. With both catalysts the hydrogen pretreated material was 2-6 timesmore active for the cis-trans isomerization of the charged alcohol than the air pre-treated sample (table 3). With the hydrogen pretreated samples, the amount ofisomerized alcohol in the liquid product was as great as the total conversion by bothdehydration and dehydrogenation.trans-2-Methylcyclohexanol conversion over thehydrogen or air pretreated MgO led to the same alkene composition ; with CaO therewas only a slight difference in the alkene compositions from the two pretreatments.The &ene composition from tr~nst2-methylcyclohexanol with both catalysts and bothTABLE 3 .-PRODUCTS FROM THE CONVERSION OF PURE 2-METHYLCYCLOHEXANOL ISOMERS WITHCALCIUM AND MAGNESIUM OXIDE CATALYSTSalcohol* methylcyclohexenealcohol pre- time conversionisomer treatment T,K LHSV /min /mol % cis trans 4-b 3- 1-MgOtrans-2- air 613 0.26 40 22 4.7 95.3 3 42 5585 18 5.3 94.7 - 47 53165 16 - - - 48 52Hz 608 0.26 95 36 33 67 - 43 57160 32 33 67 - 46 54190 29 29 71 - 47 53CaOtrans-2- air 623 0.26 60 33 14 86 6.2 37 5780 22 9.3 90.7 5.4 37 57Hz 623 0.26 35 24 32 68 6.7 43 5185 21 22 78 6.3 42 52cis-2- air 618 0.26 50 45 87 13 1.8 23 7595 39 93 7 2.2 24 74a Composition of the alcohol in the liquid reaction products ; the alcohol reactant containedc 0.1 % of the other isomer.b May contain some methylcyclohexaneB. H. DAVIS 99pretreatments differed significantly from that with the cis-alcohol over CaO. Thealkene composition from the &-alcohol over CaO is similar to that obtained withother oxides in this temperature range l9 and is probably the equilibrium com-position (considering only methylcyclohex-1- and -3-ene).The kinetics for alcohol conversion with MgO 6 g 8 * 1 0 ~ 1 1 show an alcohol reactionorder varying between zero and one. In most cases our data gave reasonableArrhenius-type plots if the rate was assumed to be zero order in alcohol.However,the temperature coefficients calculated from these plots were only z 10 kcal mol-l.This low value could be accounted for by a rate with some order other than zero.DISCUSSIONWith both CaO and MgQ, the hydrogen pretreated material was a selectivedehydrogenation catalyst while the oxygen pretreated sample had about the sameactivity for both dehydrogenation and dehydration. The selectivity was imparted bythe pretreatment and the catalyst could be changed from one selectivity to the otherby the appropriate pretreatment. Hydrogen or oxygen pretreatment determines theselectivity for many catalysts 2o but in most cases we fuund a selectivity that was justopposite to that of CaO and MgO.For example, hydrogen pretreated alurnina is avery selective dehydration catalyst but oxygen pretreated alumina is as active fordehydrogenation as for dehydration.17The sites created by the pretreatment are catalytic. For example, a run with amixture of cis- and trans-2-methylcyclohexanol using air pretreated MgQ resulted inthe conversion of 50 mmole over 6.3 g of MgO having a total surface area of 345 m2.Estimating the minimum dimension of the catalytic site as 10 A2, a size only slightlygreater than that of an oxide ion, enables one to calculate that a minimum of 10molecules of alcohol were converted per site. Since the conversion remained nearlyconstant during the run it seems clear that sites are catalytic and not transient innature.The results from the conversion of trans-2-methylcyclohexanol suggest thatdehydration and dehydrogenation may occur on different sites.The alkene fractionfrom the conversion of the trans-alcohol over both the air and the hydrogen pre-treated MgO at 613 K contained the same amount of methyIcyclohex-3-ene. Thetotal alcohol conversion was also similar. However, with the air pretreated sample81-86 % of the conversion was dehydration while only 28-29 % of the total conversionwas dehydration over the hydrogen pretreated sample. At the same time, thedehydrogenation conversion was nearly equal to the amount of the cis-trans isomer-ization of the alcohol charge for both pretreatments, suggesting that the isomerizationoccurs on the same site that is active for dehydrogenation.An oxygen species, 0; or OOH-, may serve as a site for dehydrogenation.21Tench et aZ.22 observed that 0- on MgO abstracted the a-hydrogen from bothethanol and propan-2-01. The air pretreated sample should have a higher concentra-tion of oxygen species than the hydrogen pretreated sample and should be moreselective for dehydrogenation. Since we observed the opposite effect, it appears thatthe oxygen ion is not responsible for dehydrogenation with CaO and MgO catalysts.Derouane and Gieseke 23 found that the paramagnetic centres formed byevacuation at 653 K were decreased by the adsorption of hydrogen at 293 K.In-creasing the temperature to 443 K restored many of the paramagnetic centres ashydrogen was desorbed.These paramagnetic centres were active for H2-D2exchange 24 and dehydrogenation of alcohols could be viewed as a special H2-D2exchange. Since hydrogen adsorption decreased with increasing ternperat~re,~ 9 2100 CATALYTIC CONVERSION OF ALCOHOLSwe would expect alcohol dehydrogenation to likewise decrease; this is contrary towhat was observed.The alkene distribution from the acyclic alcohols suggests that the number andkind of dehydration sites change with temperature for MgO. At lower temperatures,an equilibrium distribution was obtained with the hydrogen pretreatment while thedistribution from the air pretreated sample resembled that obtained with alumina.Thus, the hydrogen pretreated material adsorbs the alkene product more strongly soit has time to isomerize or the dehydration reaction occurs through a differentintermediate on the two pretreated materials.The different alkene distribution from pure cis- and pure trans-2-methykyclo-hexanol rule out a mechanism with a common intermediate and is consistent with ananti elimination mechanism. However, the 50 % methylcycloliex-3-ene from truns-2-methylcyclohexanol suggests a contribution from a syn elimination or an isorneriza-tion of the alkene during formation or as a secondary reaction.In summaxy, the hydrogen or air (oxygen) pretreatment determined the dehydra-tion selectivity. The selectivity is imparted by the pretreatment and can be altered bythe next pretreatment.The ability to change from one selectivity to another suggeststhat the range of selecticities reported by earlier workers probably resulted from thepretreatment. It will require more work to decide which of the variety of paramag-netic sites, if any, determine the selectivity.The author thanks the Donors of The Petroleum Research Fund, administered bythe American Chemical Society, for the support of this research.K. Tanabe, Solid Acids and Bases (Academic Press, London, 1970).K. Saito and K. Tanabe, Shokubai (Tokyo), 1969,11,2068.T. Iisuka, H. Hattori, T. Ohno, J. Sohma and K. Tanabe, J. Catalysis, 1971,22, 130.P. Canesson and M. Blanchard, J. Catalysis, 1976, 42, 205.Y. Schachter and H. Pines, J. Catalysis, 1968, 11, 147.W.F. N. M. DeVleesschauwer in Physical and Chemical Aspects of Adsorbents and Catalysts,ed. €3. G. Linsen (Academic Press, London, 1970), p. 225. ' I. M. Hoodless and G. D. Martin, Canad. J. Chem., 1975,53,2729. * N. Takezawa, C. Hanamaki and H. Kobayaski, J. Catalysis, 1975,38,101.H. Vinek, H. Noller, M. Ebel and K. Schwarz, J.C.S. Faraday I. 1977,73,734.Z. Szabo, B. Jover and R. Ohmacht, J. Catalysis, 1975, 39, 225.l 1 E. R. McCaffrey, T. A. Micka and R. A. Ross, J. Phys. Chem., 1972,76,3372.l2 P. Sabatier, Catalysisin Organic Chemistry, translated by E. E. Reid (Van Nostrand, New York,l 3 0. V. Krylov and E. A. Fokiva, Kinetika i Kataliz., 1960, 1,421.l4 H. Vinek, J. Latzel, H. Noller and M. Ebel, J.C.S. Faraday I. 1978, 74, 2092.K. Thomke, Z. phys. Chem. (Frankfurt), 1977,106,225.l6 H. Pines and J. Manassen, Ado. Catalysis, 1966, 16,49.B. H. Davis, J. Catalysis, 1972, 26, 348.B. H. Davis, J. Org. Chem., 1972, 37, 1240.l9 B. H. Davis, unpublished results.2o €3. H. Davis, Colloid Interface Sci., 1976, 3, 115.21 D. G. Klissurski, E. F. McCaffrey and R. A. Ross, Canad. J. Chem., 1971,49, 3778.22 (a) A. J. Tench, T. Lawson and J. F. J. Kibblewhite, J.C.S. Faraday I, 1972,68,1169. (b) A. J.23 E. G. Derouane and W. Gieseke, J. Mol. Catalysis, 1975/76, 1, 411, and references therein.24 M. Boudart, A. Delboville, G. E. Derouane, V. Indovina and A. B. Waters, J. Amer. Chem.25 R. Martens, H. Gentsch and F. Freund, J. Catalysis, 1976, 44, 366.26 J. E. Kilpatrick, E. J. Prosen, K. S. Pitzer and F. D. Rossini, J. Res. Nat. Bur. S t u d , 1946,1923).Tench, J.C.S. Faraday I, 1972, 68, 1181, and references therein.SOC., 1972, 94, 6622.36, 559.(PAPER 91157

ISSN:0300-9599    

DOI:10.1039/F19807600092

出版商:RSC    

年代:1980

数据来源: RSC