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Determination of the purity of monomers by a catalytic bromination method |
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Analyst,
Volume 121,
Issue 7,
1996,
Page 987-990
Nibaran C. Dey,
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PDF (480KB)
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摘要:
Analyst, July 1996, Vol. 121 (987-990) 987 Determination of the Purity of Monomers by a Catalytic Bromination Method Nibaran C. Dey, Lakhimi Borah and Anil C. Ghosh Regional Research Laboratory, Jorhat, 785006, Assam, India Titanium(1v) chloride has been found to be an effective catalyst for the bromination of olefinic monomers using pyridine sulfate dibromide as the brominating reagent. This catalytic reaction has been successfully used for the quantitative determination of the purity of monomers such as styrene, acrylic acid, hexadecene, vinyl acetate, butyl methacrylate, etc. The results are comparable with other established methods of analysis. The catalytic effect of TiCI4 was found to be insensitive to light and, therefore, free from errors induced by the effect of light, as in the case of the HgI1 acetate catalyst currently being used.The use of TiC14 as a new catalyst eliminates the risk of handling and disposal of hazardous Hg" acetate and the related environmental problems. Keywords: Catalyst; monomer; bromination; titanium(iv) chloride Introduction Quality assurance in the plastics industry demands the con- tinuous monitoring of raw materials, of which the monomer is the most important. The determination of the purity of monomers is conveniently carried out by determining the unsaturation quantitatively. Nearly all chemical reactions used for the determination of unsaturation in monomers involve the addition of a reagent to the double bond. Methods based on reagents using halogenation, hydrogenation, epoxidation, nitra- tion, thiocyanation and mercuration or addition of mercaptans, bisulfite, amines, etc., are well studied text-book methods1 of classical analytical chemistry. Of the various halogenation reactions, the most popular one is the bromination reaction used in various reaction media.Thus, bromine in acetic acid and carbon tetrachloride have been used for the determination of olefinic unsaturation by early workers.2-4 Tribromide complexes in both methanol and water have been used by various workers.5 A hydrogen perbromide complex in chloroform and bromide-bromate reagent in water are some of the other bromination reagents.+* All of these reagents suffer from some inherent disadvantage, either diffi- culty in attaining completion of the reaction or the substitution reaction which take place simultaneously affecting the accuracy of quantitative determination. One of the more successful reagents for bromination is pyridinium sulfate dibromide (PSDB) originally used by Rosenmund, Kunhenn and co-workers.9JO The active bromine in this reagent does not take part in the secondary reactions of substitution or oxidation.However, the reaction rate is very slow in the absence of a catalyst. Rowe, Furnas and Bliss' used Hg" acetate as a catalyst in conjunction with PSDB for determining olefinic unsaturation. By using approximately 70% excess of reagent they obtained good results for olefinic unsaturation. Since then, the method has been in extensive use as a classical method for olefinic unsaturation, particularly for monomers in the plastics industry. The method has some disadvantages.For example, apart from the environmental problems associated with the handling and disposal of mercury, the catalytic bromination using Hg" acetate is highly light- sensitive. It is, therefore, necessary to carry out the work in the absence of direct sunlight or other light sources. There is no literature reference to an alternative catalyst for the bromination reaction using PSDB. Literature reference to titanium(1v) chloride as a catalyst in the bromination reaction is scanty. Cresp et a1.12 have described TIC4 as a catalyst in the selective bromination of ortho- carboxyphenol to give, predominantly, the 3-bromo derivative. In the absence of TiC14 the 5-bromo compound is formed exclusively. Selective substitution in the position ortho to the hydroxy group was considered to involve a six-membered ring titanium complex.Titanium(rv) chloride in the presence of pyridine in tetrahydrofuran has been described as a catalyst in the Knoevenagel condensation. ' 3 ~ 1 ~ Titanium(1v) chloride has so far not been used as a catalyst for bromination with PSDB reagent. In the present paper we describe Tic14 in acetic acid as a new catalyst for the bromination of the olefinic double bond with PSDB. Experimental Reagents Acetic acid, glacial. The acid used was of reagent grade, passing the dichromate test. Pyridinium sulfate dibromide (PSDB) solution. This solution was prepared as described in the literature.' The solution was stored in an amber bottle in the dark. Potassium iodide, reagent grade.This was used as a 30% (m/v) aqueous solution and was prepared freshly. Sodium thiosulfate, 0.05 mol 1-1 solution. The solution was prepared and standardized by the accepted method against standard potassium dichromate solution.15 Starch, 1 % aqueous solution. The starch indicator solution was prepared by the usual procedure.15 Anhydrous titanium (IV) chloride. This was transferred to a flask containing glacial acetic acid under a nitrogen atmosphere to give a concentrated stock solution (10-20%). It was found to be advantageous to add a few drops of concentrated HC1 for the purposes of preservation. A working solution (2.5%) was prepared from the stock solution by dilution with acetic acid. Mercury(r1) acetate, 2.5% solution (m/v). This solution was prepared in glacial acetic acid.Procedure Because only a small amount of monomer in the range 0.02-0.05 g was used, depending on relative molecular mass, a stock solution was prepared by using the reported proce- dure." Determination was carried out by following the same procedure as has been reported,ll using 20 ml of PSDB reagent. Instead of Hg" acetate, an appropriate volume of TIC14 solution988 Analyst, July 1996, Vol. 121 was used so as to adjust the concentration of the catalyst as described in Tables 1-3. The final volume of the reaction mixture was adjusted to 50 ml with glacial acetic acid. After a reaction period of 30 min, 150 ml of water were introduced slowly into the reaction flask, followed by 10 ml of 30% potassium iodide solution. Titration with sodium thiosulfate solution was carried out as reported, * using starch as indicator near the end of the titration. The blank was run simultaneously through the whole procedure, omitting only the aliquot of stock solution and substituting for it 10 ml of glacial acetic acid.The percentage of monomer is calculated as (B - A) X M X M X 100 ( 1 ) Mass in g of sample in aliquot where B is the blank titre value, A the sample titre value, M the molarity of thiosulfate and M the milliequivalent mass of sample divided by 2 n, where n is the number of active double bonds. ~~ ~~~ ~~~ ~ Results and Discussion The catalytic effect of TiC14 on the bromination reaction of PSDB depended on the concentration of the catalyst in the reaction mixture. By keeping the total volume of the reaction mixture constant, the effect of concentration of the catalyst on Table 2 Comparison of rate of bromination (96) in presence of catalysts for monomers Time/min Mass of Mono- mono- catalyst Styrene 0.03515 Hg acetate 0.2500 97.0 97.6 98.0 98.0 TiC1, 0.2600 97.2 97.5 98.0 98.0 Vinyl 0.0237 Hg acetate 0.2500 93.3 95.1 99.2 99.2 acetate TiC14 0.4110 94.0 96.5 99.3 99.2 Mass of mer mer/g Catalyst /g 10 20 30 45 - - 87.7 87.7 87.7 - 64.0 64.0 64.0 - Table 1 Effect of variation of TiC14 concentration on the percentage bromination of various monomers for a reaction period of 30 min in a reaction volume of 50 ml Experiment Monomer no.Styrene (98.0% by GC) I: 1; Acrylic A (99.8% by GC) I: !I Hexadecene (99.8% by GC) J: 13 I: I: Butyl methacrylate 1: I: I! r l Vinyl acetate (99.3% by GC) (98.0% by GC) ( 1 2-Hydroxyethyl methacrylate J (98.0% by GC) Hydroxypropyl methacrylate (98.0% by GC) Mass of sample/g 0.035 15 0.0329 0.0602 0.02738 0.03488 0.04032 0.06017 Volume of PSDB (0.05 mol l-')/ml 20 20 20 20 20 20 20 Mass of TiCldg 0.0000 0.0560 0.I335 0.1896 0.2670 0.3570 0.0000 0.2100 0.4200 0.6050 0.7500 I .0500 0.0000 0.0520 0.1028 0.2042 0.2569 0.3853 0.0000 0.2055 0.2504 0.3055 0.41 10 0.4580 0.0000 0.2005 0.3230 0.5504 0.6478 0.7503 0.0000 0.1050 0.2038 0.4038 0.5804 0.7200 0.0000 0.1050 0.25 10 0.5 138 0.7707 1.0068 Bromination (%)* 87.7 89.1 92.3 94.2 98.2 98.0 35.8 48.5 82.4 93.5 99.8 99.6 87.5 88.1 89.8 92.4 94.5 99.7 64.0 88.1 92.5 96.1 99.2 99.4 30.3 50.5 65.0 85.3 98.0 98.0 25.4 35.2 46.5 62.0 89.5 98,l 46.6 56.3 66.1 80.0 98.0 98.2 * The above results are average of duplicate measurements.Analyst, July 1996, Vol.121 989 Table 3 Determination of various amounts of monomers by using optimum catalyst concentration for a reaction time of 30 min Mass of Mass of Calculated Monomer monomer/g catalyst/g purity Mean k s Styrene Vinyl acetate 0.03500 0.03535 0.03570 0.03605 0.03640 0.03675 0.037 10 0.03745 0.03780 ~ 0.03815 0.2500 98.0 98.3 98.1 97.9 97.8 98.3 98. I 97.8 97.9 98.1 1 0.02700 ( 0.02727 0.02754 0.0278 1 0.02808 0.02835 0.02862 0.02890 0.029 17 0.02944 9.4 100 99.3 99.1 99.5 99.6 99.3 99.2 99.1 99.3 99.2 99.5 i 98.03 f 0.18 ; 99.11 +0.17 the percentage bromination of the monomer substance was evaluated for a fixed reaction time. The mass of the monomer substance was kept constant for a particular set of experiments. The various nionomer solutions that were used for the study included styrene, acrylic acid, vinyl acetate, hexadecene, 2-hydroxyethyl methacrylate, hydroxypropyl methacrylate, butyl methacrylate, etc.The results of the studies are summa- rized in Table 1. The percentage bromination indicated in the table is the average of duplicate experiments carried out. It can be seen from the table that with the increase in catalyst concentration in the reaction mixture, the percentage of bromination of the monomer, for a fixed time interval, increased. For each compound the optimum amount of catalyst for quantitative bromination varied, depending on the nature of the hydrocarbon chain and the position of the doubIe bond.It is interesting to note that those compounds which brominate easily with PSDB required only small amounts of catalyst for quantitative bromination within the fixed reaction time. Larger amounts of catalyst were required for substances which do not easily brominate with PSDB alone. However, in all instances quantitative bromination was obtained with increased TiC14 concentration within a reasonable limit in the reaction mixture for a reaction time of 30 min. That TiC14 acted as a catalyst and remained unchanged during the reaction was established by determining the Ti'" chloride in the reaction mixture after completion of the reaction using a standard method.16 The catalytic effect of TiC14 in the bromination reaction was specific for PSDB reagent only. When bromine alone was used in acetic acid, together with TiC14, no catalytic effect was observed.It was, therefore, felt that some form of titanium- PSDB complexation might be responsible for the observed catalytic effect. The reactions were repeated in different shades of light (bright sunlight, diffused light) and also under completely dark conditions. No difference in the percentage of bromination was observed for any of the above compounds, indicating that the catalytic reaction was not light-sensitive. This gave the catalyst an advantage over the Hg" acetate catalyst, which is light sensitive and, therefore, requires special care if accurate results are to be obtained. Table 2 shows the progress of the bromination reaction for styrene and vinyl acetate with PSDB in the absence of any catalyst, with the optimum amount of Hg" acetate and with the optimum amount of TiC14 in the same monomer concentration for a period of 45 min.It is seen that TiC14 is equally effective for the quantitative bromination and the time required for the completion of the reaction is also identical. Table 3 shows the reproducibility of the quantitative bromination using optimum catalyst concentration for different masses of the reactant monomer. The standard deviation indicates good reproducibility with the present catalyst. The stock solution of the catalyst was found to remain active for about 1 month, after which the catalytic effect gradually deteriorated. An amber coloured bottle was found to be more suitable for lengthy storage of the stock solution. This solution, however, required to be kept under stoppered conditions because of the tendency of TiC14 to react with atmospheric moisture.We conclude that an alternative catalyst, TiC14, for deter- mining the purity of monomers in the plastics industry with PSDB by using a titration method has been found. The new catalyst is environmentally more compatible and its use simplifies the operating conditions of the experiment since it is not light sensitive. We thank the Director, R. R. L. Jorhat, for permission to publish this paper. References 1 2 3 4 5 6 7 8 9 10 I 1 Mitchell, J., Jr., Kolthoff, I. M., Proskauer, E. S., and Weissberger, A., Organic Analysis, Vol. 111, Interscience Publisher Inc., New York, USA, 1956. Manchot, W., and Oberhauser, F., Z. Untri-such. Nuhr-.-u. Genussni., 1924, 47, 26 I . Uhrig, K., and Levin, H., fnd. Eng. Chem., Anal. Ed., 1941, 13, 90, 194. McIlhiney, P. C., J . Ani. Chem. Soc., 1899, 21, 1084. Kaufmann, H. P., Studien aufdem Fettgehiet, Verlag Cheniie, Berlin, Germany, 1935. Gal'perm, G. D., and Vinogradova, J. V., Nc.Jtyunoe Khoz, 1936, 1, 59. Vaubel, W., Z. Angew. Chenz., 1910, 23, 2078. Winkler, L. W., in Phamnropea Hungaricu, Budapest, Hungary, 3rd edn., 1909, p. XI. Rosenmund, K. W., Kuhnhenn, W., Rosenberg-Gruszynski, D., and Rosetti, H., Z. Untersuch. Nahr-.-u. Genussm., 1923. 46, 154. Rosenmund, K. W., and Kuhnhenn, W., Berichte, 1923, 56, 1262. Rowe, G., Furnas, C. C., and Bliss, H., fnd. Eng. Chem.. Anul. Ed., 1944, 16. 37 1 .990 Analyst, July 1996, Vol. 121 12 Cresp, T. M., Sargent, M. V., Elix, J. A., and Marphy, D. P. H., Charlot, G., Colorimetric Determination of Elements-Principle and J . Chem. Soc. Perkin Trans. I , 1973, 340. Methods, Elsevier, Amsterdam, the Netherlands 1964, p. 409. 13 Lehnert, W., Tetrahedron Lett., 1970, 4723. 14 Lehnert, W., Tetrahedron, 1973, 29, 635. Paper 6100426A 1.5 Vogel, A. I., A Text Book of Quantitative Inorganic Analysis, Received January 18,1996 Longmans, Green and Co., Harlow, UK, 1961, p. 9.51. Accepted March I I , I996 16
ISSN:0003-2654
DOI:10.1039/AN9962100987
出版商:RSC
年代:1996
数据来源: RSC
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Cumulative author index |
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Analyst,
Volume 121,
Issue 7,
1996,
Page 991-992
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摘要:
Analyst, July 1996, Vol. 121 99 1 CUMULATIVE AUTHOR INDEX JANUARY-JULY 1996 Abraham, Michael H., 51 1 AbramoviC, Biljana F., 401, 425 AbramoviC, Borislav K., 401, 425 Abroskin, Andrei G., 419 Acedo Valenzuela, M. I., 547 Adam, S., 527 Adeloju, S. B., 699 Aherne, G. Wynne, 329 Akhtar, M. Humayoun, 803 Al-Othman, Rashed, 601 Alazard, S., 527 Alegret, S., 959 Aleixo, Luiz M., 559 Almirall, J., 959 Analytical Methods Committee, Andrade, Francisco J., 61 3 Angeletti, R., 229 AntonijeviC, M. M., 255 Appleton, Mark, 743 Aratake, Sachiko, 325 Araujo, Pedro W., 581 Arias, Juan Jose, 169 Artjushenko, Slava, 789 Bacci, Mauro, 553 Baggiani, Claudio, 939 Balasubramanian, N., 647 Bannon, Thomas, 715 Barlett, Philip N., 715 Bamabas, Ian J., 465 Barroso, C. G., 297 Banvick, Vicki J., 691 Baxter, Douglas C., 19 Baxter, Pamela J., 945 Baya, Maria P., 303 Benedetti, A.V., 541 Benmakroha, Yazid, 52 1 Biancotto, G., 229 Bilitewski, Ursula, 119, 863, 877 Birch, David J. S., 905 Bjorklund, Erland, 19 Blais, Jean-Simon, 483 Blanco, Marcelo, 395 Bogan, Declan R., 243 Bond, Alan M., 357 Borah, Lakhimi, 987 Boswell, Stephen M., 505 Bouhsain, Zouhair, 635 Boukortt, Sheriffa, 663 Boutelle, Martyn G., 761 Boyd-Boland, Anna A., 929 Boyd, Damien, 1R Brereton, Richard G., 441, 575, 581, 585, 651 Brinkman, Udo A.Th., 61 Bru, E. R., 297 Buchet, Jean-Pierre, 663 Burgot, Jean-Louis, 43 Bye, Ragnar, 201 Cai, Xiaohua, 965 CallejBn MochBn, M., 681 Cammann, K., 527 Cao, Zhong, 259 Carbonnelle, Philippe, 663 Cardoso, A. A., 541 Cardwell, Terence J., 357 Carmona, Pedro, 105 Casajus, Rocio, 8 13 Casella, Innocenzo G., 249 Cassidy, Richard M., 839 CaviC-Vlasak, Biljana A., 53R Cela, R., 297 Cepas, Juana, 49 Ceramelli, Giuseppe, 2 19 Cerda, A..13 Cerda, V., I3 Chan, Wing Hong, 53 1 Chatergoon, Lutchminarine, 373 Chen, Guo Nan, 37 573, 889 Chou, Shu-Fen. 71 Christian, Gary D., 601 Christie, Ian, 521 Cirovic, Dragan A., 575, 581 Coello, Jordi, 395 Cole, S. Keith, 495 Collier, Wendy, 877 Copeland, D. D., 173 Corbella Tena, R., 459 Corti, Piero, 219 Cosano, J., 83 Craston, Derek H., 177 Crosby, Neil T., 691 Croteau, Louise G., 803 Crump, Paul W., 871 Crumrine, David S., 567 Cullen, Michael, 7.5 Cullen, William R., 223 Daenens, Paul, 857 de Jong, Dirk, 61 de Jong, Gerhardus J., 61 de la Guardia, Miguei, 635, 923 de Lacy Costello, Benjamin P.J., de Oliveira Neto, Graciliano, 559 Dean, John R., 465 Demidova, M. G., 489 Demir, Cevdet, 651 Deng, Jiaqi, 97 1 Deng, Zhiping, 671 Desai, Mohamed, 52 1 Desimoni, Elio, 249 Destradis, Angelo, 249 Devi, Surekha, 807 Dey, Nibaran C., 987 Dilleen, John W., 755 Dobrowolski, R., 897 Dodd, Matthew, 223 Dolmanova, Inga F., 431 Dreassi, Elena, 219 Dumasia, Minoo C., 651 Dumschat, C., 527 Dunemann, Lothar, 845 Economou, Anastasios, 97 Eigendorf, Guenter K., 223 Eikenberg, Oliver, 119 El-shahat, Moharned F., 89 El-Shorbagi, Abdel-Nasser, 183 Elbergali, Abdallah K., 585 Ellwood, Jo A., 575 Ernara, Samy, 183 Ernteborg, Haan, 19 Endo, Masatoshi, 391 Eng, Jimmy. 65R Escobar, Rosario, 105 Evans, Phillip, 793 Facer, M., 173 Fallon, Michael G., 127 Fawaz Katmeh, M., 329 Feam, Tom, 275 Fell, Gordon S ., 189 Fernandes, Julio Cesar B., 559 Ferreira, Valdir S.. 263 Fielden, Peter R., 97 Fillenz, Marianne, 761 Fitzgerald, Catherine A., 715 Fleet, Ian A., 55 Forster, Robert J., 733 Forteza, K., 13 Francis, John M., 177 Frech, Wolfgang, 19 Fugivara, C. S., 541 Fukasawa, Tsutomu, 89 Fung, Yingsing, 369 Gaal, Ferenc F., 401, 425 Galeano Diaz, T., 547 Gamble, Donald S . , 289 Gao, Xiao Xia, 687 Garcia, M., 959 793 Garrigues, Salvador, 635, 923 Genrich, Meike, 877 Georgieff, Michael, 901 Ghosh, Anil C., 987 Giannousios, A., 413 Giersch, Thomas, 863 Giraudi, Gianfranco, 939 Glennon, Jeremy D., 127 Godinho, Oswaldo E. S . , 559 Goldstein, Steven L., 901 Goosens, Elise C., 61 Gordon, Derek B., 55 Greer, James C., 7 I5 Grol, Michael, 119 Groves, John A., 441 Guiberteau Cabanillas, A., 547 Guiraum Perez, A., 681 Gurden, Stephen.P., 441 Hadjiivanov, K., 607 Hammerich, Ole, 345 Hansen, Elo H., 31 Harris, Roy, 913 Harrison, Iain, 189 Hartnett, M., 749 Hauser, Peter C., 339 Hayashi, Yuzuru, 591 Hayashibe, Yutaka, 7 Hays, Lara, 65R Hendrix, James L., 799 Hernandez, Oscar, 169 Hu, Yan, 883 Hulanicki, Adam, 133 Hyland, Mark, 705 Ibrahim, Naaim M. A., 239 Inagawa, Jun, 623 Ioannou, Pinelopi C., 909 Irwin, G. W., 749 Ishida, Yasuyuki, 853 Ishihara, Masahito, 391 Isomura, Shinichi, 853 Iturriaga, Hortensia, 395 Ivanova. Elena K., 419 Iwatsuki, Masaaki, 89 Jackson, Laurence S., 67 Jaselskis, Bruno, 567 Jiang, Chongqiu, 3 17 Jimknez, Ana Isabel, 169 Jimenez, Francisco, 169 Jimenez-Prieto, Rafael, 563 Jimenez Sanchez, J.C., 681 Jurkiewicz, M., 959 Kalish, N. K., 489 Karayannis, Miltiades I., 435 Karlsson, Lars, 19 Kettling, Ulrich, 863 Kimbrough, David Eugene, 309 Kimoto, Takashi, 853 Kindness, Andrew, 205 Knoll, M., 527 Konstantianos, Dimitrios G., 909 Korda, T. M., 489 Kozik, Andrzej, 333 Kratochvil, Byron, 163 Kuznetsova, Vera V., 419 Kwong, Daniel W. J., 531 Lan, Zhang-Hua, 21 1 Lancashire, Susan, 75 Lancia, Antonio, 789 Laurie, David, 951 Lawrence, Chris M., 755 Lee, Albert W. M., 531 Legouin, BCatrice, 43 Lei, Chenghong, 971 Lewenstam, Andrzej, 133 Li, Hao, 223 Lightbody, G., 749 Lin, Hui-Gai, 259 Link, Andrew J., 65R Lipkovska, N. A., 501 Lison, Dominique, 663 Littlejohn, David, 189 Lonardi, S., 219 Ldpez Carreto, Maria, 33R Ldpez-Cueto, Guillermo, 407 Lopez, Martin, 905 Lord, Gwyn A., 55 Loukas, Yannis L., 279 Lowry, John P., 761 Lowthian, Philip, 743, 977 Lowy, Daniel A., 363 Lu, Bin, 29R Lu, Changyin, 883 Lu, Zheng, 163 Lund, Walter, 201 Luo, Yongyi, 601 Luque de Castro, M.D., 83 Lyons, Michael E. G., 715 McAdams, Eric T., 705 McAlernon, Patricia, 743 McAteer, Karl, 773 McCormack, Ashley L., 65R MacCraith, Brian D., 785, 789 McDonagh, Colette M., 785 McEvoy, Aiding K., 785 MacLachlan, John, 1 1K McLaughlin, James A., 705 McNaughtan, Arthur, 11R Madsen, Gary L., 567 Magdic, Sonia, 929 Maines, Andrew, 435 Maj-Zurawskd, Magdalena, 133 Mannaert, Erik, 857 Marr, Iain L., 205 Marshall, William D., 289, 483, Martin, Patricia, 495 Martinez-Fabregas, E., 959 Martinez-Lozano, Carmen, 477, Mason, Andrew J., 951 Maspoch, Santiago, 395, 407 Masujima, Tsutomu, 183 Mathiasson, Lennart, 19 Matsuda, Rieko, 591 Meaney, Mary, 789 Melios.Cristo B., 263 Mieczkowski, JBzef, 133 Mierzwa, J., 897 Mihajlovic, R., 255 MilaEiC, Radmila, 627 Mills, Andrew, 535 Milosavljevik, Emil B., 799 MitroviC, Bojan, 627 Mizgunova, Ulyana M., 43 1 Mo, Songying, 369 Moane, Siobhan, 779 Mocak, Jan, 357 Mohamed, Ashraf A., 89 Molina, Marina, 105 Monaf, Lela, 535 Monaghan, John J., 55 Montelongo, F. Garcia, 459 Moollan, Roland W., 233 Moore, Andrew, 67 Mosello, R., 83 Mottola, Hordcio A., 2 11, 38 1 Mounsey, Andrew, 955 Mulcahy, David, 127 Muller, Beat, 339 Munro, C. H., 835 Murphy, William S., 127 Nakamura, Masatoshi, 469 Nakamura, Motoshi, 469 Nakanishi, Masami, 853 Newton, R., 173 Nie. Lihua, 883 Nielsen, Steffen, 3 1 Nolte, Joachim, 845 817 813992 Analyst, July 1996, Vol.121 Obendorf, Dagmar, 35 1 ObradoviC, Danilo M., 401 Odman, Frednk, 19 Ohtani, Hajime, 853 O’Keeffe, Michael, 779, IR O’Kennedy, Richard, 243, 767, Olmi, Filippo, 553 Oms, M. T., 13 O’Neill, Robert D., 761, 773 Oniciu, Liviu, 363 Orlando, Andrea, 553 Osipova, Nataliya V., 419 Ostaszewska, Joanna, 133 Owen, Susan P., 465 Packham, Andrew J., 97 Papadopoulos, C., 413 Paradowski, Dariusz, 133 Pardue, Harry L., 385 Parsons, Patrick J., 195 Patel, Sunil U., 913 Patterson, Kristine Y., 983 Paulls, David A., 831 Pawliszyn, Janusz B., 929 Pedrero, Maria, 345 Pkrez-Bendito, Dolores, 49, 563, PCrez-Bustamante, J. A., 297 PQez-Ponce, Amparo, 923 PCrez-Ruiz, Tomas, 477, 813 Pergantis, Spiros A., 223 Perruccio, Piero Luigi, 219 Piggott, Nighel H., 951 Pihlar, Boris, 627 Pingarron, Jose, 345 Piperaki, Efrosini A., 11 1 Piro, R.D. M., 229 Pitre, K. S., 79 Poe, Russell B., 591 Poole. Colin F., 51 1 Power, J. F., 451 Prodromidis, Mamas I., 435 Proinova, I., 607 Proskurnin, Mikhail A., 419 Qu, Yi Bin, 139 Quevauviller, Ph., 83 Quinn, John G., 767 Rader, W. Scott, 799 Rae, Bruce, 233 Raghunath, A. V., 825 29R 33R Rahmani, Ali, 585 Ramanaiah, G. V., 825 Ratcliffe, Norman M., 793 Razee, Saeid, 183 Reddn, Miguel, 395 Regan, Fiona, 789 Reimer, Kenneth J., 223 Reinartz, Heiko W., 767 Rigby, Geraldine P., 871 Rios, Angel, I Rodriguez Delgado, M. A., 459 Rodriguez-Medina, JosC F., 407 Rohm, Ingrid, 877 Rowell, Frederick J., 951, 955 Rowell, Vibeke, 955 Rubio, Soledad, 33R Ruzicka, Jaromir, 601, 945 Sadler, Peter J., 913 Sakslund, Henning, 345 Saleh, Gamal A., 641 Salinas, F., 547 San Martin Fernhndez-Marcote, Sanchez, Ma.J., 459 Santos, Jose H., 357 Sanz, Antonio, 477 Sato, Hidetoshi, 325 Satyanarayana, K., 825 Sayama, Yasumasa, 7 Schafer, E. A., 243 Schieltz, David, 65R Schmid, Rolf D., 863 Schoppenthau, Jorg, 845 Scobbie, Emma, 575 Scudder, Kurt, 945 Seibert, Donna S., 51 1 Sekino, Tatsuki, 853 Seviour, John, 95 1 Shah, Rupal, 807 Shanthi, K., 647 Shijo, Yoshio, 325 Shiraishi, Haruki, 965 Shukla, Jyotsna, 79 Shulman, R. S., 489 Silva, Manuel, 49, 563 Siskos, Panayotis A., 303 Slater, Jonathan M., 743, 755 Slavin, Walter, 195 Sloth, Jens J., 31 Smith, Clayton, 373 M., 681 Smith, Dennis C., 53R Smith, Robert F., 67 Smith, Roy, 321 Smith, W.E., 835 Smyth, Malcolm R., 779, IR, 29R Smythe-Wright, Denise, 505 Sokalski, Tomasz, 133 SOlC, s., 959 SolujiC, Ljiljana, 799 Stathakis, Costas, 839 Stegman, Karel H., 61 Stegmann, Werner, 901 Stevenson, Derek, 329 Stone, David C., 671 Strachan, David, 951,955 Stradiotto, Nelson R., 263 Stuart, Iain A., 11R Stubauer, Gottfried, 351 Subramaniam, K., 825 Suffet, I. H. ‘Mel’, 309 Sukhan, V. V., 501 Suliman, Fakhr Eldin O., 617 Sultan, Salah M., 617 Sumodjo, P. T. A., 541 Sweedler, Jonathan V., 45R Szklar, Roman S., 321 Tam, Wing Leong, 531 Tan, Yanxi, 483 Tang, Bo, 317 Tang, Shida, 195 Tegtmeier, M., 243 TepavEeviC, Sanja D., 425 Thastrup, Ole, 945 Thomaidis, Nikolaos S., 11 1 Thompson, Michael, 275, 285, 67 1,977,53R Thornes, R. D. , 243 Tian, Baomin, 965 Timperman, Aaron T., 45R Tomis, Virginia, 477, 813 Torgov, V. G., 489 Townshend, Alan, 832 Troccoli, Osvaldo E., 613 Tsuge, Shin, 853 Tudino, Mabel B., 613 Tyson, John D., 951,955 Tzouwara-Karayanni, Stella M., Ubide, Carlos, 407 Uehara, Nobuo, 325 435 Vadgama, Pankaj, 435,521, 871 Vaggelli, Gloria, 553 Valckcel, Miguel, 1, 83 Vassileva, E., 607 Veillon, Claude, 983 Verbeek, Alistair, 233 Viles, John H., 913 Villegas, Nuria, 395 Vos, Johannes G., 789 VukanoviC, B., 255 Walker, P. J., 173 Wallace, G. G., 699 Walsh, James E., 789 Walsh, Peter T., 575 Wang, Bin-Feng, 259 Wang, Chen, 317 Wang, Jin, 289, 817 Wang, Joseph, 345, 965 Wang, Ke-Min, 259, 531 Wang, Shi-Hua, 259 Watanabe, Kazuo, 623 Wheals, Brian B., 239 White, P. C., 835 Whiting, Robin, 373 Wickstrom, Torild, 201 Wilmot, John C., 799 Wittmann, Christine, 863 Wood, Roger, 977 Woolfson, A. David, 71 1 Wu, Weh S., 321 Xin, Wen Kuan, 687 Xu, Xue Qin, 37 Xu, Yuanjin, 883 Yamada, Shinkichi, 469 Yao, Shouzhuo, 883 Yates, 111, John R., 65R Yu, Ru-Qin, 259 Zanker, Kurt, 767 Zanoni, Maria Valnice B., 263 Zaporozhets, 0. A., 501 Zhang, Fan, 37 Zhang, Xiaogang, 317 Zhang, Zhanen, 971 Zhi, Zheng-liang, 1 Zhou, Dao-Min, 705 Ziegler, Torsten, 119 Zolotova, Galina A., 43 1
ISSN:0003-2654
DOI:10.1039/AN9962100991
出版商:RSC
年代:1996
数据来源: RSC
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