摘要:

J O U R N A L OF THE CHEMICAL SOCIETY. PAPERS READ BEFORE THE CHEMICAL SOCIETY. I.--Mod$cutions of Double Xulpliates. By SPEXCER UNFKEVILLE PICKERING, M.A. Oxon, Professor of Chemistry a t Bedford College. IB a previous communication t,o this Society (C71,em. h'oc. J., Trans., 1854, G86), attention was drawn to the great discrepancies which exist in the determinations of the heat of dissolution of anhydrous potassium magnesium sulphate, it being, according to Thomsen, 10,602 cal., and according to Graham only 7000 cal. An investiga- tion of the corresponding copper salt, CuKK,(S0J2, led to an esplana- tion of these discrepancies. Potassium Copper Xulphate. This salt may be prepared without any difficulty by mixing hot; concentrated solutions of the constituent sulphates in equivalent pro- portions, and allowing the mixture to cool.The liquid should not be heated to within 20" or 30" of its boiling point, otherwise an abundant crystalline precipitate will be formed, which, according to Bruriner (Poyg. A Y ~ , 15, 476), consists of a basic double salt having the composition C u K, ( S 0,) 2 , 2 C u S Og , Cu 0 ,4H.10, decomposable by water, leaving an insoluble residue of the te trabasic copper sulphate, cuSo*,3cuo. A considerable quantity of the crystallised salt, CuK2(SOJ,,6H20, having been prepared in the above manner, the crystals were powdered, washed, and dried by exposure to air, after which they VOL. XLIX. R2 PICKERINCI : MODIFICATIONS OF DOUBLE SULPHATES. were found to contain the theoretical percentage of water within experimental error.When heated a t loo", this hydrated salt parted quickly with the whole of its water, leaving the anhydrous salt in the form of a blue powder as dark in colour as the hydrated substance itself: when, however, this blue salt was heated to a temperature of 150--200", i t was found to lose its colour and become white, or very nearly white ; this white modification in its turn underwent a change when the temperature was further raised to about 300" or 400", and became again blue or bluish-green. This third modification remained apparently unchanged by any additional increment of temperature till the melting point of the salt was reached a t a low red heat. The molten salt forms an opaque green liquid, which solidifies to form a, glassy mass ; as soon, however, as the temperature falls sufficiently low, this glass suddenly crumbles into an opaque blue powder resembling in every respect the blue modification obtained at 400".The behaviour of the fused salt has been noticed by previous observers (Thomsen, J. pr. Chem., 18, 35), but the white modifica- tion has hitherto escaped observation ; indeed, when operating on small quantities of the salt, it appears difficult to obtain i t a t all. It is necessary to cool the fused or strongly heated salt as quickly as possible, for, if cooled slowly, it will often revert partially to the white form, and it is, moreover, necessary to fuse it in quantities not exceeding 5 or 6 grams, in order to avoid any decomposition, as i t begins to evolve sulphuric anhydride at a temperature very little above its fusing point.The curious changes of colour experienced by this salt suggested its existence in distinct modifications: which might be more fully investigated by measuring their heats of dissolution. Various specimens were, therefore, prepared and examined in this way. The results thus obtained are embodied in Table I (p. 6). The first column in this table gives the number by which the samples were designated for the convenience of future reference. Nos. 3415, 3424, and 3425 were obtained from a totally different preparation of the hydrated salt to that from which the others were obtained. w = weight of salt taken, W = the water equivalent of the calorimeter and its contents, the volume of the water in it being 601,678 + 0.016 To c.c., which, according to Berthelot's simplified method of calcul:tt8ion, is reckoned as being equivalent to the same number of grams with a specific heat of unity (see JIthanique Chiqnipue, 1, 190).Column VII records which therniometer was einplojed in thePICKERING : MODIFICATIONS OF DOUBLE XULPHATES. 3 experiment ; the temperature 7, t, and t' being given in the arbitraq- degrees of these instruments. 7 = temperature of the salt a t the moment of its introduction into the calorimeter. t = the initial, and t' the final temperatu1.e of the calorimetric liquid, corrected for (1) the temperature of the salt , where c is the specific heat of the ( t - 7)wc w + 20 according to the equation salt ; (2) the exposure of the mercurial column t o the temperature of the air ; ( 3 ) the calibration correction.The molecuhr heat of dissolution (Column XII) is given by the equation M = (" - 'IaW where M is the molecular weight of the salt (333*02), and a the mean value of the arbitrary degrees of the thermometers in degrees centigrade, this being in the case of ther- momet'er 81, 0*38663", and with 83, 0.38046". The next column gives the initial temperature in degrees centi- grade. The figures in the other columns will be explained shortly. The proportion of water to salt taken was about 800 : 1 mol. For experimental error, &c., see Trans., 1884, 686. Some small correction should be applied to some of the numbers given in this table, owing to the presence of a little basic and insolu- ble salt which the white speciAens always contained.The greatest quantity which was ever found amounted to 0.2 per cent. (in the case of the white modification), and would necessitate a correction of about + 12 cal.; some of the specimens of the third modification contained a similar impurity also, not exceeding, however, 0.06 per cent., corresponding to 6 cal.; these amounts are so small in corn- parison with the experimental errors that it was not thought neces- sary to correct for them. The first modifications as well as the fused specimens contained no such impurity. The majority of the experiments quoted in this table were per- formed a t an initial temperature of 18.25" C., and, confining our attention for the moment to thcse experiments only, it will be seen that all the blue specimens which were obtained a t low temperatures dissolved with practically the same evolution of heat, namely, 9709 cal.; t'he white specimens evolve a very much smaller amount of heat on dissolving, about G%UO cal.only, though the various numbers here are not so closely concordant as they are with the blae specimens, from a cause which will be mentioned shortly ; lastly, the blue specimens obtained at higher temperatures evolve an amoun t of heat differing from either of the others, namely, 8407 cal. There can be no doubt, therefore, that the successive changes of colour indi- W B 84 PICKERING : MODIFICATIONS OF DOUBLE SULPHATES. cate the formation of distinct modifications of the salt, which may be conveniently designated as a, p , "J. The method of preparation OF the different specimens was varied as much as possible. No difference is made in the nature of the a-modi- fication, whether it is obtained at the lowest tempwatnre at which dehydration is complete, or at the highest temperature (about 130" as indicated by a thermometer in an air-bath*) which can be employed without risking the formation of some of the white salt. The various white specimens were obtained either direct from the hydrated salt, or from t'he blue anhydrous modification, and a t temperatures ranging from 180" to 220°, but in all cases they yielded identical numbers, showing that this modification also has zt perfectly definite existence.The second blue or ymodification, which begins to appear a t 250- 300", is in a similar manner perfectly stable throixghout a considerable range of temperature, and even after fusion yields the same numbers on dissolution.The specimen, No. 2737, which alone gave numbers lower than the others, was known to contain some of the white modi- cation unaltered. The heat of dissolution decreases, of course, and decreases rapidly, with the temperature of the water, and we can examine those results ohtained with khe p- and ymodifications a t temperatures other than 1 8 2 5 O , only by comparing them with the heat of dissolution of the a-modification a t identical temperatuTes. Where nit, and Mp repre- sent the heats of dissolution of the a- and P-modifications respectively a t To, the heat of formation of the p- from the a-modification a t that temperature is Ma -MB. The values of Ma a t the necessary tem- peratures are given in Column XIV, having been deduced from numerous experiments, the details of which i t is not necessary to give here, and the values of (Ma--Mp) and (Ma-M,) are given in Column XV.These values, the heat, of transformation of the a- into the p- and cpmodificntions will, however, not be constant quantities, unless the specific heats of all the modifications are identical. Where this is not the case, the heat evolved, Q', in any chemical reaction at T', may be calculated from that evolved, Q, at any other temperature T by means of the equation Q-c'(T- T') = &'-c(T-T'), in which c represents the sum of the specific heats of the reacting substances, and c' that of the substances formed (see Berthelot, Me'c. Chim., 1, 105).It was necessary, therefore, to determine the specific heats of the salts in question ; the details of these determinations will be more conveniently given elsewhere, the general results only being here :* In snch a case, the tlierinometer being placed abme a dish containing some 100 grams of the salt, the lowcr portions of the salt get heated, no doubt, 20" or 30" sbore the thermometric reading.PICKERISG : RlODIFIChTIONS OE' DOUBLE SULPHATES. 5 stated. The molecular heats 01 the three modifications were found to be- c, = 56.025 c, = 58.735 cp = 51.24 Substituting these values for c and c' in the above equation, the results obtained a t the various temperatures were all reduced to 18-25", and entered in Column XVI of the table. I n the first place with regard to the y-modification, the numbers thus obtained are not identical, as they should be, but show a, regular increase with the temperature ; it is difficult to account for this fact otherwise than by assuming that the specific heat of this modification is considerably greater a t these temperatures (8-23') than experi- ment showed it to be a t 8-43".I n order to render the figures in the last column identical, the value of c y would have t o be 70 instead of 58.7, or at any rate the difference between the two specific heats C, and c,, would have to be five or six times greater than the determinations gave it. Such a supposition is scarcely admissible, and it will be pre- ferable to take those experiments only which were performed at 18*25", and which give + 1302 cal. as the heat value of the trans- formation of the a- into the ymodification at that temperature.The numbers in the last column, which refer to the formation of the white modification, show also a considerable variation, but here the variation may be accounted €or without difficulty. Berthelot has shown (,4nn. China. Phys. [5], 29, 295, et seq.) that most double as well as single salts after fusion do not a t once attain their normal and stable condition as regards their thermal properties, and it seems not improbable that a similar period of instability may intervene after they have been heated, even without fusion (see Trans., 1885, 99), especially if, as in the present case, this heating has been accompanied by some distinct molecular rearrangement.Unfor- tunately, at the time when these experiments were made, now nearlx two years ago, Berthelot's results had not been published, and tlie intervals which had elapsed between the preparation and dissolution of a sample were not accurately noted ; the dates which are given in Column IV are, therefore, for the most part approximations only; but, nevertheless, they show satisfuctody that the white samples dissolve 1%-ith an evolution of about 230 cal. more after they have been kept for some days than they do when freshly prepared. Taking the different samples separately- No. 2739 dissolved after three days with a heat evolution which gives the value of M,-Mp to be 3590 cal. (Expt. 9) ; after 10 daSs the value (calculated for 18.25") was reduced t o6 PICRERING : MODIFICATIONS OF DOUBLE SULPHATES.3326 (Expts. 16 and 17) and 3296 (Expts. 7 and 8) ; after 130 days, to 3396 (Expt. 14) and 3393 (Expt. 15) : an average reduct>ion of 264 + 294 + 194 + 197 - No. 2750 after three days gave the value 3476 (Expt. 12) ; after 10 days, 3299 (Expts. 18 and 19) ; and after 130 days, 3284 237 cal. 4 -> (Ii7 s Ig2 => (Expt. 13), showing an average reduction of 185 cal. in this value. No. 3425 dissolved after one day gave 3602 (Expt. 20) ; and after 60 days, only 3271 (Expts. 21 and 22) : a reduction of 331 cal. No. 2716 dissolved after one day gave 3528, Le., 200 cal. abore the average of other samples dissolved aft,er keeping. No. 3415 alone showed no change on being kept 44 days ; but as it gave only 3360 cal. as the value of the reaction when dis- solved immediately after preparation, it would appear as if some peculiarity in the details of its trent'ment had reduced i t a t once to that state in which this modification remains stable.Summing up these results, it seems evident that some change takes place which is complete in about 10 days, and which results in the salt dissolving with an evolution of about 230 cal. more than it does when freshly prepared, the actual numbers being 6159 cnl. a t first, and 6489 cal. eventually, the transformation of the a- into the p-rncdiiication evolving 3550 and 3220 C R ~ . , according as either the former or t,he latter of these above numbers is t'aken; preferelice should be, perhaps, given to the lat'ter, as it corresponds to the more stable condition.A compitrison of Expt. 6 with Expts. 1 to 5 shows that the a-modi- fication undergoes no change of this desrription ; and a comparison of Expt. 27 with 28, and of 34 with 31 to 33, shows the same fact with regard to the ymodification. Expt. 15 proves that prolonged heating of a, white specimen, at temperatures below that of its preparation, does not induce any change i n it. The heat development on the passage of one inodification into another, as given above, is calculated, of course, on the assumption that, all the three modification5 when dissdved in water, form iden- tical solutions, an assumption which tlie appearance and behaviour oE the solutions, as well as the absence of further thermic effects, fully justifies. The heat of formation of the double salt fi-om its constituenh sul- pliates, x, will be given by the following equation :- This number will therefore be adopted.TABLE I.-Heat of Dissolution of Anhydrous Potassium Copper Xulphate, CaK,(SOJ, = 333.02; wzol.= 12.488 grams. a XIV. 1 nest of lissolution of the a-modification at To C. 11. Colour. 111. Method of preparation. -- x. t'. IV. Date of experiment after that of preparation. V. W. VI. w. VII. Therni. VIII. 7. IX. t. XI. i'- t. XII. XIII. To C. I. 8 ample. Value of the change of the a- into the 6- or y - modification at M, Molecular heat of dissolution. XVI. 8 -25O C. XV. To C. "}2717 2. .... 4. 3*}2744 . . . 5. 2746 .... 614 -12 614 -12 614.12 614 *21 614.21 614 *21 18 *62 18'52 20 -35 26 -54 25 S9-E 21 -65 21 -456 21.3845 21 *397 21 - 7795 21,705 22 -3735 22.988 22 *8905 22 '948 23 *3385 23 *222 23 *910 ______ 34 -872 344 '9025 22 -5235 22 .$I3 22 -303 22 %a7 23 -483 23 *35% 23 -087 33 .51'2 33 -409 33 -429 33 .4.94 23.984 23 -945 24.032 18*066 18.354 18.194 18.190 -- ____ 35 -6395 35 -246 23 '523 23.004 22,556 23 *046 22 *844 23 -545 19 -265 19 '282 Crystals dehydrated at 100" ; sifted Crystals heated at 50'; sifted and Crystals heated at 80") and then and reheated at 100-130".reheated at 100-120". at 115". - }About 1 day . . ), 3 ), . * * * 1 *532 1 '506 1.651 1 '559 1.517 1.5335 1 a091 1 *082 0 -9615 0 '991 0*9605 0 -976 1.0145 1 *qo55 0.994 0 -944 0 *915 0 -956 0 '944 0 *782 0 T395 0.8255 0 -7405 0 -759 0 *752 0.758 ._ 1 *tzo95 1 *385 1.271 1.2875 1 -346 1 *337 1.306 1.235 1 *062 1 '069 12.392 12 * 434 12.588 12 *605 12 '4423 12 *471 12 *603 12 743 12 -435 12 *636 12 *329 12 ,478 12 -497 12 -589 12.416 12 * 377 12 *532 12 '610 12 ' 727 12 '551 11 '123 12 -382 12 *530 12 500 12 *456 12 * 633 81 81 81 81 81 81 81 81 81 81 81 81 81 81 81 83 83 83 a3 83 83 83 83 83 83 83 Blue...... { ,, . - . . a . { .......... .......... i Nearly white Quite white { %-&rlY { - Nearly white - c Quite white . ,9709 18 *25 - 3296 3590 3528 3476 3284 3396 3393 3326 3299 3602 3271 3360 3339 1252 1302 1444 )) 120 days., R 7.44 J 6. 2744 and 2746 6782 6115 6181 6233 6425 6313 6316 5807 5834 4848 5179 4661 4683 Crystals heated at 215" ; sifted and A blue specimen heated at 220" Crystals heated at 180" ; sifted and Some of 2739 after being reheated reheated at 195".- - aft& being sifted. reheated at 195". - - at 100-120" for 19 hours. { } About 10 days 614.27 614 -27 614 -12 614 -12 614 -12 614 -21 614 -21 614 -21 614 *21 614.03 614 *12 614.03 614.12 614 *06 614 * 08 614.08 614.02 614 * 02 614.02 61 i'0-3 35 * 6% 35.32 18 a45 17 -32 18 :20 25 '43 21 -57 21 -41 21 *m 37 '37 35 '87 37 -92 36 *47 22 *84 22 *63 23-02 17 '37 17 *2S 17.34 17 -56 33 '781 33 $8205 21 -552 21'452 21 -3425 21 -651 22 *4685 22 -352 22 '093 32 *598 32 -494 32'473 32 -550 23 -202 23 -2055 23 * 2065 17 -3255 17 * 595 17 -442 17 *432 34 *230 33 -861 21 *262 21 *7165 21 '210 21 *709 21 a 538 22 '310 19 *203 18'213 10100 9709 9110 8410 '1970 22 -91 I )- 1s *25 I ! \ 13 '37 1 } 9-85 } 7.64 22 -98 18 -25 7 *935 3318 - - - I - I 3303 3276 3562 3231 3309 3288 1239 - 1472 - 9.10'}2716 11. .... 13. 12.}2750 * . { 14. 2739 .... 15. 3087 .... :;:.}2739 .... .... 22. n>3415 .. { 26. Y ) 10 >) { -i 1 day.. .......... 60 days ........ 2 hours ........ 44days ........ Crystals heated at 180" ........ ........ -I. Crystals heated at 200" 1 614.27 614 *27 614 -12 614 *12 614 *12 614 *21 614 -21 318 -37 614 *03 614.03 34 -76 29-19 22 *70 22 -82 15 *25 23 -37 23 -47 22 -67 17 -15 1r *84 27. 2743, 2751 and 2752 28. 3069 .... !SO. r2g*} 2737 . . . 31. 2743 .... 32. 2751 .... 33. 2752 .... 34. 3069 .... 36. 35*} 3424 .... Blue.. ...... !) ....... )) ...... { . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .......... . . . . . . . . . . 88921 8866 12 *4t9 12.380 12 -608 12.334 12 -626 12 -549 12.383 5 -995 12 *536 12.743 81 81 81 81 81 81 81 81 83 83 - About 10 days .............. 10105 Fused.. ........................ A white specimen heated over a Hcat.ed below redness.. .......... Nearly fused.. ................. Fused.. ........................ Fused.. ........................ burner ;' not homogeneous. Partially fused.. ................ .. ; '. { .... .... .... ,. * . tyW7 9709 8030PICRERING : MODIFICATIONS OF DOUBLE SULPHATES. 7 in which MKMg, MK, and M,, are the molecular heats of dissolu- tion of the double salt of potassium sulphat,e, and of copper sul- phate respectively,* and N t'he heat disturbance on mixing solutions of the single sulphates. This latter quantity was found to be nil, in accordance with the observations of other physicists, and the values of M, and M,, were found by means of numerous experiments t o be - 6495 and 15633 respectively at 18.25O ; the algebraic sum of these is + 9138, and hence the heat of formation of the a double salt will be (9138 - 9709 =) - 571 cal., i.e., it is an endothermic com- pound.The other two modifications on the contrary would be formed hy exothermic reactions :- [K,80a + CuSOd = B-CuK2(SOJz] = 2649 cal., and [&SO, + CuSO, = yCilK,(SO,),] = 3 1 ,, That all these three salts are in reality componnds, and not mere mixtures of the uncombined sulphates of copper and potassium, is clearly shown by the fact that none of them dissolves with the heat evolution with which the mixed salts would, namely 9138 cai., and that those two modifications which approach most nearly to this quan- tity are both blue substances, whereas a mixture would be white; the only modification which is white dissolves with an evolution of as much as 2649 cal. less than a simple mixture would do.I t remains only to be added that whereas the first change under- gone by this salt, the passage of the a- into the /?-modification, is an exothermic action evolving 3220 cal., the second change, that of the /3- into the ymodification, is an endothermic act,ion, absorbing 1918 cal., 8,s measured a t 18.25". The mean of two determinations of the heat of dissolution of this salt which were made hy Thomsen gave 9396 cal. a t 17-27", whereas at this temperature the a-modification, according t>o my experiments, would evolve :I61 7 cal. on dissolving, indicating that l'homsen's speci- men had been overheated, and contained some of the P-modification.The experiments, however, are not strictly comparable xith mine, as he used a proportion of water amounting to only two-thirds of that used by myself. Potassizcna Magnesium Sulpltate. An investigation of potassium magnesium sulphate conducted on the same lines as that of its copper analogue was found to be com- plicated by various circumstances. * If the single sulphateB are dissolved in 400 molecules of water, the double sulphate must be dissolved in 800 molecules in order to make this equation correct. These proportions were taken.8 PICEERING : MODIFICATIONS OF DOUBLE SULPHATES. I n the first place, considerable difficulty was met with in preparing the salt itself in a state of purity.The double salt is considerably more soluble than its component snlphates, and, therefore, unlike the copper salt, it does not crystallise out on mixing saturated solutions of the two sulphates. The mixed liquids should be evaporated while hot, and then allowed to cool ; spontaneous evaporation should not be resorted to, and the magnesium sulphate should be present in considerable excess, otherwise the crystals separating out will con- tain a large quantity, or even consist entirely of uncombined potas- sium sulphate. Moreover, since the double salt is entirely decom- posed by an excess of water, the crystals should be washed free from mother-liquor only by means of a saturated solution of the double salt itself. After many unsuccessful attempts, a large quantity of the crystallised salt was prepared containing the theoretical pcr- centage of water ; from this, the anhydrous specimens were obtained.But here another difficulty arose. Just like magnesinm sulphate itself, the double salt does not lose its water at the same low tempera- ture, and with the same ease as the copper compound does. The whole of its water is not evolved below 155", and, as i t was feared that this temperature would be sufficiently high to induce some change in the constitution of the salt, the same expedient was adopted as in the case of magnesium sulphate (Trans., 1885, l O l ) , namely, dehydrating the salt as far as possible a t the required tempe- rature, and making a correction for any residual water which is still retained.This correction was made in the same way as for magne- sium sulphate, necessitating a knowledge of the heat of dissolution of the hpdrated salt as well as that of the anhydrous salt a t some par- ticular temperature. The former of these quantities was found to be - 9777, and the latter, as will be shown below, + 12037 at 22.28", and, consequently, the correction to be applied to the numbers obtained with a sample retaining, for instance, 0.6 per cent. of the total water present when fully hydrated would be - of (12037 + 9777) cal. The various corrections are given in Column X of Table I1 (p. 9), while the method of preparation and other details are given in the last column. All the experiments in this case were made a t the same temperature, 22-28' U., with the exception of those with sample No.3432, where the results a t a higher and a lower temperature gave the means of calculating what the number would have been obtained at, 22.28". The symbols used are identical with those in Table I. The sp. ht. of the salt was taken as 0.17. To begin with, we are met by the same fact observed in the case of the copper salt ; that all the specimens prepared a t low temperatures, ranging in this case from 110" to 155", are identical in nature, and give 0.6 100I. Sample. I. 3054 2. 3054 -- a. 2796 4. 3000 5. 2796 & 3000 6. 3039 7. 3039 8. 3432 9. 3432 10. 2794 11. 2794 12. 2i93 13. 3038 14. 3003 15. 8001 16. 3002 li. 3040 15. 3050 19. 3070 -- 20. 3070 TABLE lI.-lIeat of Dissolution of Anhydrous Potassium Magnesium Sulphate, MgK2(S04)2 = 293.64.3 - mol. = 11.013 grams, 80 - 11. W. - 11.067 11 -094 11 -184 11 -049 11'011 11'140 11.027 11 -240 11 -139 11 '037 11 '070 11 '138 11.171 11'118 11 '090 11*170 10.931 11 '011 11.014 10.946 - - - JII. w. 614.27 614.27 614'27 614.27 614.27 614.27 614.27 614.30 615-97 614.27 614.27 614-27 614.27 614 '27 614.27 614.27 614'27 614.27 614.27 614'32 - - IV. rherm -- 81 81 81 81 81 81 81 81 81 81 81 81 81 81 81 81 81 81 81 Iu) - - V. 7. -- 28 -68 28 236 36 '36 35 '06 32 '77 31 '53 32.19 36 '72 28 '84 30 '19 28 '08 30 '36 31 *96 32 -76 31 '17 31 *28 32 -3 1 32'21 34.23 -- 32 9 3 - VI. t . -- 32.117 32 *1875 32 '324 32 .Of325 32-230 32'2315 32 '2'285 37.1605 28 '859 32 '222 32 -027 32 '1 62 32 '221 32-276 32 *123 3' -200 32 '1455 32 '206 32.258 31 -444 VII.t'. -- 33 '3495 34'0385 34 '234 33'9515 34.134 34'163 34.116 39 'OG8 30 '59 0 33 938 33.772 33 '630 33.5715 33 '542 33 -352 33 '403 33 '309 33.4715 33 -438 32.601 ~- VIII. t'-t. -- 1 '83?5 1 '851 1 -910 1 '889 1 '9U4 1 -9315 1 -88i5 1 -847 5 1 '731 1'716 1 '745 1 '468 1 '3505 1 266 1 -229 1 -203 1'1635 1 2655 1 -180 1 -157 -- IX. M. 11603 11925 11925 12071 11475 a t 24.22" C i0878 at 21.01' C: ] - - X. Correction. --- + 417 + 120 + 54 + 87 0 0 XI. M corrected. 1 12020 XII. /_--- Hemarks. Prepared at 110' C.; retaincd 1.92 per cent. of the total water. Prepared a t 130"; retained 0.60 per cent. water. Prepared at 130' ; retained 0.25 per cent. water. 1 Prepared at 155"; anhydrous. 22-28' 11112 I Prepared at 170". :::;:] 10936 ,, 192'. 8440 240". 7949 920 1 ,, 215O.PrepaE)ed belaw a red heat. 7736 I -.. at a red heat. 7.718 rarii'ally fused. 8023 Fused. Dissolved 4 days after- 7431 1 Fused. \Yards. 7207 1 7570 wards. ' Fused. Dissolved 2 hours after- 7388( 1 prr;?. Dissolved 1 year after-10 PICRERING : MODIFICATIONS OF DOUBLE SULPHATES. the same evolution of heat on heing dissolved, namely 12037 cal. a t 22*28", the numbers obtained being very concordant, when it is remem- bered that a correction depending on the accurate determination of a very small quantity of water had to be applied to most of them. 15.5" appears, however, to be very near the lirnit within which such results are obtained; when heated to 170" the samples show a con- siderable clecrease in their heats of dissolution, just as in the case of tlio coppei.salt, and this decrease becomes rapidly greater as the temperature employed is higher, till it reaches a climax in the fused specimens, of which the heat of dissolution is only about 7400 cal., or not much more than one half of t,hat of the specimens prepared below 155", and which may be termed the a-modification. No modification intermediate between the a-modification and the fused salt appears here, as is the case with the copper salt, but it would, I think, be rash to say t'hat such does not exist. 1% is a character- istic of the magnesium salts, in contradistinction to the copper salts, that their dehydration, and the various changes which they undergo, not only take place a t higher temperatures, but are merged one into another, so that it is of ten difficult to obtain one of the products free from a certain amount of the others (see Trans., 1885, 101).Such is very probably the case with the double salt. It may be either that ,.tn intermediate modification is formed between 755' and a red heat, but that the range of temperature tlironghout which it is obtainable is so small that' the conditions of the present experiments never su6ced t o produce it unmixed with the other two modifications (in which case the fused salt should be termed the third or y-modificat'ion), or else it may be that the temperature a t which the clianges tjake place heing so much higher than they are in the case of the copper salt, the very highest temperature (a bright red heat) which the salt is capable of bearing without decomposition is high enough to form only the second instead of the third modification ; if this be so, the fused salt should be termed the /%modification.The latter riew is, perhaps, preferable. seeing that the heat of dissolution of this last modification is so much smaller than that of the first one, bearing towards it about the same ratio as the p- does to the a-pot'assium copper sulphate. The fused salt exhibits two peculiarities which the unfused samples do not. When thrown into water, it! dissolves with extreme slowness, it does not cake, but forms a milky liquid which becomes clear only after the lapse of about, 25 or 30 minutes. This has also been noticed by Berthelot (Ann. Chirn. Phys. [5], 29, 329), and resembles, thougli in an intensified form, the behaviour of monohydrat ed magnesiuni sulphate.The second peculiarity is that, when first put! into water, a full of nearly 0.1" precedes the rise in temperature : this, no doubt,PICRERING : MODIFICATIONS OF DOUBLE SULPHATES. 11 is due to its passage into the a-modification previous to its disso- lution. The length of time required f o r the dissolution of the fused speci- mens renders the beat determinations very difficult ; indeed, these can be regarded as approximations only. Omitting Expt. 18, which appears to be exceptionally high, the mean of the last fim experiments giws 7431 cal. as the heat of dissolution of /3-MgK,(S0,)2, and the value of the transformation of the a- into the /?-modification as + 4606 cal., measured at 22.28". According to my own experiments, potassium sulphate dissolyes in 400 mols.of water, a t this temperature, with an absorption of 6200 cal., and magnesium sulphate, under like conditions, with an evolution of 20722 cal. This gives the followir,g values for the heat G f formation of t,he double salt from its component sulphates :- [hfgSOA + K2S01 = a-BilgK2(SO,),] = 2485, [MgSO, + K,SO1 = /?-~IgK,(SO,),] = 7091, both reactions being exothermic. of the fused salt ; his results when reduced to 22.28" become- Dissolved at once , . . . . , . . . . Berthelot (Zoc. cit.) determined the heat of dissolution of a specimen (1) 8059 cal. '7132 ,) (6432 ), ,, after i3 weeks . . . . (4) ), and finely powdered 5588 ,,% from which he concludes that after being kept, this salt dissolves with a decreased evolution of heat, due to its parting witIh some of the heat it had absorbed during fusion, and further, that powdering facilitates this loss.' My own experiments, on the contrary, if they show any change at all in the behaviour o€ the salt when kept, show an increase i n the heat of dissolution (comp. Expt. 18 with 17, and 20 with 19), a change similar in nature to that which certainly takes place with the /3-copper salt.? The difficulties of experimenting in this case, however, are so great that much weight cannot be attached to these * Berthelot's actual numbers are-(1) a t 17", '7300 cal. ; ( 2 ) and (3) a t 20.1", 6880 and 6180 cal. ; (4) a t 20*8", 5421 caL Taking with these my own determinations of the lieat of dissolution of potassium ~ulphate and of magnesium sulphate a t these three temperatures-which are with the former -6600, -6340, and -6390, and with the latter 20353, 20610, and 20654 cal. respectirely-we get for the rnlue of the eqna- tion [MgS04 + K2S04 = /3-MgK2(S0,)2] 6483, 7390, 6432, and 5538 cal. in the four experiments, and the difference between these quantities and the sum of the lieats of dissolution of magnesium and of potassium sulphate a t 22.28" produces the numbers given in the text. t. Neither the fused copper nor any specimens of the y-modification showed any change on keeping.12 PICKERING : MODIFICATIONS OF DOUBLE SULPHATES. differences, and it will be sufficient to remark that, on the whole, Berthelot's experiments are fairly concord2nt with my own, the mean of his giving 6798, or that of his first t'hree 7201 cal." against t'he mean which I have taken for mine, 7431 cal. The salt examined by Thomsen (J, p ~ . Chem., 18, 27), dissolved with an evolution of 900 cal. less than that of the a-modification, showing that this preparation was either not anhydrous or that it had been over-heated and partially converted into the &modification. The great insolubility of anhydrous alum points, I think, to the probability of its being in reality different in constitution from the hydrated salt ; unfortunately this very insolubility and the difficulty with which it parts with its water renders any experiments similar to the present ones impossible. It appears to be a moot point whether anhydrous alum is absolutely insoluble or not ; so far as my experi- ence goes it is certaiiily not, but a t the same time I have found it quite impossible to deprive alum entirely of its water without causing i t to lose a very appreciable amount of sulphur trioxide. Pure anhydrous alum is probably unknown.

ISSN:0368-1645    

DOI:10.1039/CT8864900001

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

12 PICKERING : MODIFICATIONS OF DOUBLE SULPHATES. II.--,Mod$cations of Double 8ulphates.f Part 11. Spec@ Heat Deteriii iibations. By SPENCER. UYFREVILLE PICKERING, M.A. OXXI., Professor of Chemistry at Redford College. DOUBLE sulphates of the type M”M’( S0,),,6H20 were originally regarded by Graham (Phil. Mag., 6, 327, 417; 10, 216, &c.) as derived from the corresponding heptahydrated magnesian sulphates by the displacement of one of the molecules of water contained in them by one molecule of an alkali-metal sulphnte. T’homsen ( J . pr. Chem., 18, 29) controverted this idea by attempting to prove that the f All the specimens used by me were Anely powdered, but the powdering was performed as soon as the fused salt had solidified and while it was still quite hot. It is possible that a slight absorption of moisture during the powdering of Berthelot’s specimen, while cold, may be the cause of low results of Expt.4. The proportion of water used by Berthelot was smaller than that used in my own experiments, and hence an absolute concordance of results cannot be expected. f- This communication formed part of a paper entitled “ Notes on the Constitu- tion of Hydrated and Double Salts,” which was read before the Society. The theoretical portion of this paper will be published hereafter.PICKERING : MODIFICATIONS OF DOUBLE SULPHATES. 13 heat of combination of the various water molecules in the double sul- phate was very different from that of the water molecules in the cor- responding single sulphate. I have already shown, however (Trans., 1885, l02), that the experimental data on which Thomsen relied were incorrect, and I shall elsewhere endeavour to prove that his argument was founded on a theory which is quite inadmissible.Substitution or displacement is one of the many ideas in chemistry which do not admit of any exact definition, and we can only settle whether one substamce is a true substitution-product of another by general considerations as to the mode of its formation, and the exient to which it retains the fundamental characteristics of the parent, sub- stance. The case now under consideration is, I think, as true an instance of substitution as any which can be adduced. The manner in which the double sulphates are obtained is of the simplest character, and they exhibit the peculiarities of the sulphates from which they are ob- tained, even to the most minute details. The heptahydrated sulphates lose 6H,O a t about lOC)", leaving the monohydrate M"S04,H20, whilst at tlhe same temperature the double salts part with their 6H20, leaving the salt M"S04,K2S0,.I n the case of the copper compounds, both of theRe are of a light blue colour, and both, when raised to nearly ZOO", are decomposed, forming white substances, the anhydrous salt in the one case, and some differently constituted double salt in the other. The peculiarities which distin- guish magnesium sulphate from copper sulphate are accurately repro- duced in the double salts which it forms; the monohydrate is not obtainable a t loo", but requires a temperature of 150-160" for its formation, and begins t o suffer decomposition at a few degrees higher ; in like manner the doubie salt does not part with its water below 155", and begins to pass into another modification a t 170" ; the monohydrate cannot be completely decomposed a t a temperature below 250-300" instead of 200", as in the case of the copper salt, and the double salt also requires a temperature considerably higher than 200" to change it into the second modification.Person was the first to show that the specific heat of a hydrated salt, is equal to the sum of the specific heats of the anhydrous salt and of the water contained in it,. reckoned as solid water. Subsequent experiments have invariably confirmed this view, and, though I have reason to doubt its absolute correctness, it is probable that no direct determination of specific heats would be sufficiently accurate to detect any flaw in it.Now, if it were found that the specific heats of the double sulphates resembled those of the hydrated sulphntes in being equal to the sum of those of their constituents, such a fact would lend strong support to the view that they were similar in constitution to these14 PICRERING : MODIFICATIONS OF DOUBLE SULPHATES. hydrated salts. An investigation of the specific heats of the three modifications of anhydrous potassium copper sulphate was, therefore, undertaken. The method employed in these determinatioiis consisted in dis- solving a portion of the salt in water under precisely the same con- ditions as for the determination of the heat of dissolution, except that the temperature of the salt, instead of being nearly identical with that of the calorimetric water, was about 35" higher.The salt to be dissolved was weighed out into a short wide test-tube fitted with a small thermometer ; this tube was fixed in a short-necked flask nearly full of water, the whole being heated in mi air-bath to the required temperature. The flask with the water acted as a jacket to the tube coiitainirig the salt, thus allowing its renioval from the bath to the calorimeter without any appreciable alteration in temperature during the few seconds so occupied. This method cannot of course claini any of the accuracy attained by Pape, Kopp, and others using very elaborate apparatus, but it was found to give results suficiently accurate for the present purposes.The specitic heats of salts as given by different authorities difler so much that it was thought advisable to make determinations of those of copper and of potassium sulphate, a t the same time, and with the same apparatus as the double salts. The results are given in the accompanying table (p. 16), where the symbols used are similar to those in the tables in the previous comniunication. In each case the same sample was used both for the determination of the specific heat and of the molecular heat of dissolution, M.rn is the moleculai- heat of dissolution in the specific heat experiments without any correction f o r the salt temperature 7, which, in these cases, is given in degrees centigrade, as also is the interval through which the salt was cooled ( 7 - - t ) .The other temperatures Ere given in arbitrary degrees as pre- viously. c is the specific heat,, water = 1 ; and cm the molecular specific heat. The three modifications of potassium copper sulphate, it will be seen, are as clearly distinguished by their different specific heats as they are by their different heats of dissolution. The a: gives 56.025, or 0.168, the /j 51.24, o r G.154, and the y 58.735, or 0.176. Now the sum of the specific heats of copper sulphate and potassium sulphate is 544.46, or 0.164, but it is probable that this is somewhat smaller tliaii it should be, for, owing to the powdery nature of anhydrous copper sulphate, some particles of it often float on the calorimetric water before they sink, and these must consequently part with some of their heat to the air, thus giving too small a value for the specitic heat of the salt: were it not for this, the sum of the specific heats of the mixed sulphates would no doubt approach more nearly to that of thePICRERING : MODIFICATIONS OF DOUBLE SULPHATES. 15 a-modification of the double salt thau it does.Even as it is, howevei., the numbers are sufficiently concordant* to show that if any of the modifications has a specific heat nearly corresponding to that of i t mixture, it is the a-, and not the p- or y-modification. It is in the a;, therefore, if in any, that the potassium sulphate present appears to perform the same function as water in the hydrated single salt. Such a view is in full accordance with the fact that the a-modification is obtained from the crystallised salt a t the lowest possible tem- perature, and that this latter in its mode of formation and general characteristics closely resembles the fully hydrated single sul- phate.It will be noticed that the heat of combination of MgSO, + K2S0, = 2485 cal., whereas MgSO1 + H,O = 7016 cal. ; and again, that CuS04 + K,SO, = - 571 cal., whereas CuSO, + H20 = 5143 cal. ; the molecule of water which is combined with considerable energy being displaced by a molecule of potassium sulphate which combines mith lout feeble energy. I t must be remembered, however, that it is the hydrafed, and not the a d ~ ~ d r o u s salt which is prepared from the mixed sulphates, and when we take the heat-formation of this we find that in the case of the copper salt, whereas the sulphates K,SO, and CuS0,5H20 in crystallisiug out separately would evolve 9212 cal., the double salt would evolve 13,728 cal., and hence the facility with which it may be formed, and its perfect stability when formed ; the magne- sium salt, however, cannot be formed with the same ease, and is entirely decomposed by excess of water ;+ this is due to the fact that in crystallising out it would evolve only 9851 cal., a quantity smaller thau that wliich MgS04, 7H20, and K,SO, would separately, 10,310 cal.I t s formation is possible only in the presence of a large excess of magnesium sulphate, or else a t a high tetnperature, where the relative values of some of these quantities are no doubt changed. The absence of any thermal disturbance on mixing solutions of the component sulphates is generally taken as indicative of the non- existence of the double salts in solution.I n the case of the potassium magnesium sulphate this may be so, for this salt is entirely decom- posed by water, but i t can scarcely be so with the copper salt, for, if it were, it would be difficult to see why any of it should separate o u t at all on mixing the solutions, unless it be regarded as an insoluble * Quite as concordant, as they me found to be with hydrated salts. f- -4 sample of CuS04,K,S04,6H,0, which gave on analysis 24.45 per cent. of water (theorj 24.443) after being wwhed continuously till three quarters of it had been dissolved, contained 24,456 per cent., i.e., the same as before the washing. A eaniple of the magnesium salt containing 26f409 per cent.of water (theory 26.822), after being similarly treated was found to contain only 18 89 per cent., showing that it contained 30 per ceut. of uncombined potassium sulphate.1 6 PICRERING : MODIFICATIONS OF DOUBLE SULPHATES. substance, a view which is hardly reconcileable with its composition and properties." By means of the specific heats, the heat of formation of the various modifications of the copper salt may be calculated a t the temperatures at which they are actually formed. The conversion of the a- into the &salt at 18.25" C. = 3220 cal., and a t 200" i t will be 4089 cal., as given by the equation- H - cp(T' - T) = H' - ca(T' - T) (see p. 7), the heat of its formation, and therefore the tendency which it has to form increases with the temperature.The transformation of the 6- into the 7-modification is an endo- thermic reaction, absorbing 1918 cal. as measured a t 18*25", and its being such accounts, no doubt, for the ease with which it reverts to t?ie p-modification unless cooled rapidly (see p. 2), whereas the /3-modificntion being formed in an exothermic reaction, exhibits no tendency to revert t o the a-modification from which it is formed (see But here an anomaly arises : at about 300°, the lowest temperature a t which the ry-modification appears, its formation will be even more endothermic than a t 18.25O ; applying the equation given above, mutatis rnutnndis, it will be found to be - 4031 ca1.T when formed from the /3-modification, or 459 cal. when formed from the a-modifica- t'ion, the formation of the /3- from the a-modification at this same tem- perature being 4490 cal.In other words, although t'he tendency to form tJhe /3-modification (as measured by the heat, development) in- creases continuously with the temperature, and the tendency to form the ./-modification decreases with the temperature, yet a certain rise of temperature converts the former into the latter. The only conclusion which can be drawn from this is that the heat development is not the determining factor of this change. We have here a striking excep- tion to Berthelot's " Principe de Travail Maximum " (I@&. Chem., 2, 417), which has of late been attacked to no inconsiderable degree. * Satorated solutions of copper and potassiuui snlphates were mixed at 12'.About 48 per cent. of tlie sulphates present crystallised out in the form of the double salt. On performing a similar experiment with the magnesium sulphate, no crystallisation took place till about 45 per cent. of tlie water had evaporated, and then it was the uncombined salts which separated out. Zinc and nickel sulphates resemble copper sulphate in this respect, whereas those of iron and manganese resemble magnesium sulphate. The formation of the double salt in the liquid appears to be a process requiring a considerable time. In one case, it mas found that only 60 per cent. of the total crystals yielded had separated out after 12 hours, and in another case, after 24 hours, 95 per cent. J. According to the experiments on the heat of dissolution this number should be eren grrater than when based on the direct determination of the specific heats (see p.7). P. 7).8pec;fic Heat Determinutiom. -I t' - t or t - t'. -- 2'337 2 *318 2 *342 2 -346 2 *0125 2 *0045 -_I 5 -0495 5 *064 5 '023 5.036 5.655 5,319 - m. ~ t. -- 24 * 530 24.515 24 -515 24.491 24 -5215 24 -4765 ( r - t ) O C . W. -- 607 -92 607.92 607 -92 607' -92 607.92 607 *92 t'. -- 22 * 193 22 a197 22.173 22 *145 22 - 509 22 -472 -- 30 *491 30 %365 30.5315 30 4585 31 -0685 30 8905 -- 20 -1885 20 *571 20 -324 -- - 24.3495 24.356 1\11. Sample. m - M. 1055 1090 --- 687 748 -_- 1988 1040 -- 1G84 1732 1_1- 2099 2010 Therm. -- 83 83 83 83 83 83 -- 83 83 83 83 83 83 -- 83 83 83 to. 7. --- 24 -34 24 *35 24 * 3'7 24 -44 42 *59" C. 42 *98O C. -- 25.52 25 *?'l 26 * 11 25 -93 44 -75" C. 43 * 80" C. .-- - 18 -99 44 -23' C. 42 -39" C. -- I 43 '34O c. 43.05' C. -- - 43 -40' C. 42 *48" C. c. -- 0.188 0.192 12.980 12 *978 13 *062 13,092 13 -147 13 -169 -- 11 -945 11 *988 11 -907 11.946 12 -838 12 -023 -- 12.141 12.388 10 '096 - 7253 - '7223 (42 *59 - 10.35 =) 32.5 (42 -98 - 10 *34 =) 32 * t - G167 - 6132 7222 7222 32 -74 33.39 33 *OG5 614.05 G14.05 614 *05 614.05 614.09 614.09 614 -03 614 -03 614 -03 -- 21 and 22 614 -08 614.08 -- 35 and 36 6 14.08 614 *08 15687 15644 15670 15670 25 *4415 25.4725 25 * 5085 25 *4225 25 *4135 25,5715 18.9385 18.978 19 -032 -- - 23 -2345 23 *225 -- - 18.317 18 '249 16357 16418 (44.75 - 10.68 =)341* (43 '80 - 10 *745 =)33* 20.16 22.63 21 * 395 --- --- 8010 at 8 '21" C. 1,250 1 -593 1 -292 -- - 1 *115 1 -131 - 1 '372 1 * 460 10004 9956 8016 8016 55.24 56-81 44.23 - 8 '24 =) 35 *9I 4i2.39 - 8'24 =)34*lf --*._I 5179 at 9-86' C. See Expts. 12 -6M 12 -732 -- Bee Expts. 12.320 13 246 in Table I. 88 83 -- in Table I. 83 83 6863 6911 5179 5179 (43 '34 - 9 *86 G ) 33.4t (43 '05 - 9 '86 =) 33.11 50.30 52.18 - 19.689 19 -709 8664 8576 6565 6565 (43'44) - 7.97 = 35.4: (42.48 - 7*96 ={ 34.5: 69 * 24 58.23 58.735 -

ISSN:0368-1645    

DOI:10.1039/CT8864900012

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

17 111. An Eumzi,)iation of t h e Phenol! Constitzlenls of Blast-ficrnace TaT, obtained hy the Alexander and McCosh Process at the Gartshemie Ironworks. (Part I .) By WATSON SMITH, Lecturer in Chemical Technology in the Victoria University, Manchester, with Mews. J. F. H. COUTTS and H. E. BROTHERS. A PAPER was read by one of as before the Society of Chemical Industry (Liverpool Sectim), December 29th, 1583, '' On a Preliminary Examination of Blast-furnace Coal-tar," from the Gartsherrie furnaces, in which Scotch coals are used (mostly unsuitable for coke making). In this paper the following observation mas made in the examination of the higher boiling oils (gee Jozcr. Xoc. Chem. ha., 2, 495), when the losses by treatment with sulphuric acid and alkali respectively were determined by suitable measnrements.The oils of higher boiling poiiit contained more compounds abwrbed b y acids (basic constituents) a n d less plLe?zol constituents almwbed by sodu, than the oils boiling below them. It was now determined to ascertain approximately what proportions of crude phenols, and of amido- or basic-constituents, are contained in those portions of the tar-oils analogous to the carbolic-oil and creosote- oil of ordinary coal-tar. For this purpose, known volumes of the oil were repeatedly treated with caustic soda-lye until exhausted o phenol-constituents ; the la+ter were liberated by acid, collected, and measured, with the following results :- Per cent. by vol. of plienols obtained. By the 1st treatment with equal vol. of caustic soda of By the 2nd treatment with 0.65 of their volume of soda By the 3rd treatment with 0.75 of their volume of soda By the 4th treatment with 0.65 of their volume of soda 1.08 sp.gr. ................................ 17.5 of 1-15 sp. gr. .............................. 4.6 of 1 . 2 0 ~ ~ . gr. .............................. 0.7 of 1-25 sp. gr. .............................. 0.3 Total .............. 23.1 In order to determine the percentage of basic constituents present, 1160 C.C. of the blast-furnace tar-oils were shaken for a day with 840 C.C. of dilute sulphuric acid of about 1.2 sp. gr. After standing 12 hours, the aqueous layer was separated, and treated, first with a VOL. XLIS. C18 SMITH, COUTTS, AND BROTHERS : PHENOL certain excess of caustic soda, and then with common salt; after which it was allowed to stand in a graduated jar.The volume occu- pied by the layer of bask substances was read off, and it was then removed by means of ether ; the ethereal solution being heated to expel the ether, and the basic residue again measured. I t was observed that though t,he odour of the crude bases resembled that of the quino- line bases, yet it was by no means so marked in these bases as in the case of the basic oils obtained &om ordinary coal-tar oils by a similar process ; 1160 C.C. oils by this trea)tment gave 150 C.C. of crude bases = 11.09 per cent. by volume. These blast-furnace tars are consequently very rich in phenols, which may be roughly stated to constitute 20 per cent. of their volume. This proportion far exceeds what can be obtained in a similar mmner from ordinary coal-tar oils (gas-retort coal-tars), and we wodd point t o this circumstance as being to some extent a con- firmation of K.E. Schulze's theory with regard to the probable formation of, a t all events, a considerable proportion of the aromatic coal-tar hydrocarbons, by the breaking up a t higher temperatures of first-formed phenols into the elements of water and hydrocarbons (see Annalen, 227, 143). In such case, we should expect to meet with intermediate tars, which contain, in predominating quantity, these half-way pheiiol constitueiits, if they may so be termed. These blast-furnace tars (and probably t o a less extent the Jameson and Aitken coke-oven tar-oils) are of this intermediate character. If Schulze's theory be correct, amongst these phenols we ought to be able to find those members most nearly corresponding to the hydrocarbons which predominate in what we may term normal coal- tar, produced in gas-retorts a t the highest temperatures.For the purpose of testing this question, we have made a careful examination of the blast-furnace tar phenols, with the details and results which follow :- A rough quantitative fractionation was made of the crude phenols obtained (Jour. Soc. ChenL. Ind., 2, 497) by prolonged agitation of about 14 gallons off the tar-oils of sp. gr. 0.988 with an equal bulk of caustic soda-lye of sp. gr. 1.08, and subsequent treatment of the soda solution with excess of sulphuric acid (2 gallons of dark brown- coloured phenols of sp. gr.1.07 being obtained); this showed that whereas only 5.63 per cent. by volume distilled over between 180" and 210", no less than 30 per cent. passed over bet'ween 210" and 240'. The results of the fractional distillation were, in fact, as follows :-CONSTITUENTS OF BLAST-FURNACE TAR. 19 Below 190". ............. 190-200 .............. 200-210 .............. 210-220 .............. 220-230 .............. 230-240 .............. 240-250 .............. 2.50-260 .............. 260-270 .............. Per cent. by rol. 1.33 0.90 3.40 6.00 1 10.84 8.52 6.80 8.147 .............. 3*6*5 18.0 percent. 270-280 280-290 .............. 2-66) 290-300 .............. 3-72 300-360 .............. 2.88 360" to coking of residue. 13.50 91-70 The portion which distilled over below 180" consisted chiefly of water, and was disregarded. The other fractions, which remained liquid at .ordinary temperatures (that distilling from 360" to coking of the residue solidifies to a red semi-nolid resin), were now dried by remaining in contact with fused calcium chloride for some time.Each of these fractions was then decanted, and submitted to refractionation, all of such fmotions distilling below 300" being separated carefully into sub-fractions of 5" each, whilst those from 300" to 350" were, as far as possible, separated into fractions of 10" each. The fractionations were repeated, and the selections ma4e in the usual way, when it was found that by far the larger porhion of the phenols distilled between 210" and 29.5". During the distillation of thr portions boiling below 300°, much sulphuretted hydrogen was at first, evolved, and later on sulphurons acid ; a t the same time, a considerable deposit of fltee sulphur was formed in the condensing tubes. This evolution of sulphuretted hydrogen and sulphurous acid 3 with deposi- tion of sulphur, is most marked with the lower boiling portions, and is evidently due to the decomposition of peculiar sulphur compounds, unstable on distillation. After a few distillations, the evolution of gas ceased, and the phenols then possessed a much pleasanter .odouy.In fractionating the portion distilling from 300" to the coking point of the residne, it was observed that just at the coking point a peculiar decomposition occurred, both hydrocyanic acid and ammonia being evolved, distinctly recognisable by their odours.It is probable that this may be due to the decomposition of peculiar higher nitriles i n presence of a limited amount of moisture and hydrogen, ammonia and c 220 SMlTH, COUTTS, AND BROTHERS : PHENOL h-jdrocyanic acid being formed. It seems strange at first sight that nitrogenous compounds of this kind should be present in the phenols after the solution in soda and precipitation with acid ; but even such a non-basic substance as naphthalene is often found in crudephenols. For further operations, the final fractions were classified into three groups: (A) All the fractions boiling below 230"; (B) all boiling between 230" and 300" ; and (C) all boiling above 300". Examination of the Constituents of Group A . The fractions in this group were distilled until they boiled pretty constantly ; each was then placed in a freezing mixture, when that boiling from 180" to 185" at once crystallised to a solid mass, melting again at - 3".The next fraction showed signs of incipient crystal- lisation at - 13". The first consisted chiefly of phenol, C6H5-OH, but was not quite pure, as the low melting point shows ; it contained small quantities of meta-cresol. A larger proportion of cresol is pre- sent in the other fraction refusing to crystallise above - 13". The examination had not proceeded far before it was found that on dissolving %he various fractions in soda, milky solutions were formed, indicating the lingering presence of certain impurities Their removal was effected by shaking the milky solutions with ether, and separating the ethereal layer by means of a tap-funnel.Sulphuric acid then liberated the pure phenols, which were dried over calcium chloride and refractiontited. The solutions of the higher boiling phenols in caustic soda had a blue colour, increasing in depth with the rise in boiling point. So far it was satisfactorily proved that the phenols boiling between 180" and 200" consisted chiefly of phenol, C,H,*OH, and the cresols, but that the proportion of cresol to phenol was very much larger than in ordinayy crude phenol similarly extracted from gas-tar. It may be interesting, however, to mention that the relative amount of phenol, CeHS*OH, in the crude phenols of blast-furnace tar considerably exceeds that found in the crnde phenols extracted from the Aitken and Jameson tar-oils (that is, by using for a given volume of the different tar-oils the same proportion of caustic soda solution of the same strength).The following table, based on the results of the fractional distillations of the crude phenols obtained by the same process from blast-f urnace tar and from Jameson coke-oven tar, shows as far as such results can do, the similarity of these crude phenols as well as their chief difference, namely, that whereas the blast-furnace product abounds in the phenols boiliug between 200" and 230", that from the Jameson coke-oven tar is rather deficient in them. The relative proportions, however, of the different phenols in the fraction distilling between 230" and 250" are very similar in the two varieties.CONSTITUENTS OF BLAST-FURNACE TAR.21 TLr,ble compa.ring the Results of Fractionating the Crude Phenols frona Blast-furnace and Jameson Coke-oven Tars, t h e Water being deducted. Temperature centigrade. Below 180°.. ........ ,) 210 .......... .. 220.. ........ .. 230 .......... .. 240 .......... ,, 250 .......... .. 260 .......... .. 270.. ........ .. 280 .......... .. 290 .......... .. 300.. ........ .. 360 ......... 360’ to coking point . Coke and loss.. ...... Phenols from blast- furnace tar, per cent. 1 *4 4.5 6 -4 14.3 11 -5 9 *l 7.2 8.7 3.9 2 . 8 4.0 3 . 0 14 ’3 8.9 100.0 Phenols from Jameson coke-oren tar, per cent. Below .......... 5.5 223” .......... 10.0 235 } .......... 14.8 250 } .......... 9.6 270 .......... 5.6 300 Pibch (residue) 26 *Ci - LOBS ......14.8 - i 100.0 When similar methods of extraction are employed for oils distilling between the same temperatures, from- 1. Ordinary Lancashire gas-retort coal-tar ( L‘ carbolic oils ”), the yield is about 5 per cent. by volume of good crude phenols, containing 65 per cent. (vol.) of a carbolic acid, sufficiently pure t o crystal- lise a t ordinary temperatures with ease. 2. T h e blast-furnace tar, the yield was 17.5 per centl. by volume of phenols containing tbe small quantity of phenol, CsH5*OH, indicated in the table just given, and in the results recorded before t8he table. (By exhaustive treatment with alkali 23.1 per cent. was extracted.) 3. T h e Jameson coke-oaen tar-oils, the yield was about 5 per cent., and the amount of phenol, CsH5*0H, was extremely small, consider- ably smaller than that obtained from the blast-furnace tar.(By exhaustive treatment with alkali, about 8 per cent. could be extracted.) It will be seen how far these results; in the case of the blast- furnace tar, coincide with what we might expect, assuming the truth of Schulze’s theory, to the effect that in the formation of aromatic hydrocarbom by the destructive distillation of coal, phenols are primarily formed, and these subsequently suffer disruption at the higher temperatures, yielding water and hydrocarbons of the aromatic series. The Jameson product is scarcely a coal-tar, and may be regarded as a still nearer approach to the shale oils of the paraffin shale distiller.22 SMITH, COUTTS, AND BROTHERS : PHENOL We should be very slow, however, to decide that the aromatic hydrocarbons are always formed in this way during the destructive distillation of coal, though strongly inclined to believe that phenols arc more easily formed first and a t lower temperatures than the aromatic: hydrocarbons, and also that such phenols by decomposition a t the higher temperatures do give rise to a certain proportion of the hydrocaibons.Still, we think it is qnite possible that this may be entirely in accordance with facts, and yet that the theories of 0. Jacobsen (Bey., 1877, 853), Berthelot (Conzpt. rend., 62, 905-947), and Anschiitz (Bey., 1878, 1215), as to the synthetic formation of hydrocarbons of the benzene series, and of naphthalene, phenarithrene, and anthracene, may also hold good under special circumstances and conditions.It is needless to point out that were Schulze's theory the only solution of the problem, it would be difficult to account for the amount 'of benzene in gas-tam, seeing ,that amongst the phenols so abundantly present in low-temperature coal-tars and oils referred to in this paper, phenol itself is so scanbily present. But i t will now be necessary to proceed with the description of the results we obtained with the other higher boiling phenols in the group of fractions (A) boiling below 230". The portion passing over between 210" and 225", one of the largest fractions, was distilled over hot zinc-dust or passed over hot iron- borings, the product obtained was distilled, and the distillate shaken with caustic soda solution, t o remove any unaltered pheuols.The insoluble upper layer, smelling like the ordinary " solvent naphtha " of coal-tar, was then dried over calcium chloride and carefully frxc- tionated. It distilled between 115" and 150°, and apFarently, t,herefore, consisted of a mixbure of xylenes with a little toluene, irdicating tkat the material operafied on was probably a mixture of xylenols with a little cresol. The result of the fractionation showed that the chief portion of the hydrocarbons obtained distilled between 135" and 145". The fraction which boiled constantly a t 135-145", and smelt exactly like xylene, was analysed, and the following numbers were obtained :- I. 11. Calculated for xylene, CBHIO, per cent. per cent. per cent. Carbon.. . . . . 90.84 90.5 1 90.56 Hydrogen .. . 9.20 9.22 9.43 A vapour-density determination (Victor Meyer's method) gave 3-57 as the result, the calculated vapour-density of xylene being 3-67. The material passed over the hot zinc-dust consisted of a propor- tionate mixture of the fractions distilling between 205" and 230". One of the largest of these fractions distilled pretty constantly between 205" and 215". A portion of this shaken with water gave aCONSTITUENTS O F BLAST-FURNACE TAR. 23 blue colour on addition of a drop of ferric chloride, and an alcoholic solution of the phenol gave with ferric chloride a dark green tint, turning blue on addition of water ; unsymmetrical metaxylecol [l : 3 : 41 boils a t 211.5", and gives the same reactions with ferric chloride. A specimen bought as pure metaxylenol from the firm of Langfeld and Beuter of Rostock, gave the above react<ions, and on distilling a portion it was found to distil pretty much as our product did, between 205" and 215".Seeing that this specimen was prepared from pure materials designed to yield the xylenol in question, it may be considered as sufficiently proved that the substance we examined consisted of nietsxylenol [l : 3 : 4) ; and seeing that it composed the chief part of our phenol-product boiling between 205" and 230°, and that the xyleiies of gas-tar consist chiefly of metaxylene, we think there is sufficient coincidence between these results and K. E. Schulze's tlicorg, to be of interest, and to render them worthy of reeord. Exarninatiorb of the Constituewts of Group B.The fractions distilling between 230" and 3C 0" were redistilled several times, but no very definite or constant boiliiig points were attained. A mixture of them was taken and distilled over hot zinc- dust (tine iron-borings were found to answer quite as well), when a product smelling like coal-tar napht'ha was obtained. The portion of t h i s boiling below 180" was washed with caustic soda and water, dried over fused calcium chloride, and then fractioned. The portion of this boiling below 180" was washed with caustic soda and water, dried over fused calcium chloride, and again fractioned ; the portion boiling pretty constantly between 150" and 175" was taken, but there was too small a quantity of it to admit of making both a combustion and a vapour-density determination ; che odour bore a strong pesembl- ance to that of pseudocumene. A vapour-density determination by Victor Meyer's method gave 4.01, whilst the calculated vapour-density for trimethylbenzene is 4.15.Hence the chief phenol constituent pre- belit in the fraction named seems to be pseudocumenol. Mesitylol was not likely to hare heen present a t all, a t all events in more than traces, since its boiling point is 220", and the specimen distilled from zinc- dust only cornmenced to distil at 230". Pseudocumene, boiling a t 240", would he of coiirse included in this, and thus the trimethyl- benzene obtained, as before stated, might be expected to consist of yseudocumene with but traces of mesitjlene. The portion of the reduced product bailing above N O 0 , was now taken, and was found to have paytially solidified to a semi-crystalline mass.The liquid portion was poured off from this, and the crystal- lint: solid residue was washed with caustic soda and then with sul-24 PHENOL CONSTITUENTS OF BLAST-FURNACE TAR. phuric acid. I t passed over almost entirely between 205" and 220", whilst the fraction distilling between 210" and 220", solidified completely to a white crystalline mass, which readily sublimed on application of gentle heat, yielding beautiful crystalline plates, melting between 70" and 80". The odour of the substance, and its ready response to Vohl's cha- racteristic reaction, as well as its melting and boiling points, proved it to be naphthalene, and the amount obtained indicates the presence of naphthol* in considerable quantity in the phenols boiling between 220" and 300" from the blast-€urnace tar.It was washed again, dried, and finally distilled. Exanzination of the Constituents of GI-oup C. (Boiling above 300".) To remove all traces of hydrocarbons from these fractions, the phenols were each redissolved in strong caustic soda solution, the solution then largely diluted, and afterwards repeatedly shaken with toluene. After completely removing the toluene, sulphuric acid was added, the phenols liberated, collected, dried, and redistilled. On passing a mixture of t'hese higher boiling fractions twice over red hot zinc-dust, a product was obtained yieldins a fair amount of naphthalene, again testifying to the amount of naphthols in the tar. The higher boiling portion of the hydrocarbons consisted of a buttery-yellowish mass, in which we failed to detect any anthracene.It is proposed to examine this portion further so as to ascertain, if possible, what hydrocarbons do exist in it. On distilling over red hot zinc-dust o r iron-borings, it was observed that the higher boiling group of phenols, C, gave far less deposit of carbon than the lower one in groups A and B. So far then, we have proved that in the phenols obtained so abun- dantly from blast-furnace tars (the same remarks will probably be true of the phenols of the Aitken and Jarneson coke-oven tars), there are present- Ordinary phenol. . . . Cresols. . . . . . . . . . . Xylenols . . . . . . . . . . Trimethylbenzene- phenols . , . . . . . . Naphthols . . . . .. . . C1,B,.OH. The redistilled portions of the phenols boiling above 350" were tested to discover whether any azo-colours of acceptable shades could be obtained from them. For this purpose, sulphanilic acid was di- azotised, and the diazobenzenesnlphonic acid treated with small * See also Ber., 16, Ref., 150; and Ann., 227, 143 (K. E. Schulze). CeH5*OH. CsH4(CH,).0H (chiefly metacresol, 1, 3). CaEZ3(CEZ3),.0H (metaxylenol, 1, 3, 4). C,H,(CH,),.OH (pseudocumenol).GLADSTONE AND TRIBE : ALUMINIUM ALCOHOLS. 25 quantities of the phenols in alkaline solution ; brown and red dyes were obtained, but none of them were of inviting appearance. It is quite possible, however, that trials of this kind might lead t o unsatisfactory results, from the fact that none of the phenols tested could be other than mixed products. I n coi~clusion, we beg to state that we are far from asserting that nothing but phenols (the homologues of CsH,*OH) are present in the oils examined, and it is quite possible, for example, 6hat phenol-ethers may also be found in them. It is cerhin that some compounds not found in ordinary gas-tar phenols similarly extracted, are present, for whereas K. E. Schulze (Zoc. cit.), in his examination of the latter was able to isolate from t'he portions boiling behween 230" and 300", both a- and p-naphthols, we found it quite impomible to obtain them in the crystalline form from our blast-furnace tar-phenols when following Schnlze's method. Evidently some oily or resinous phenoloid bodies obstinately adhered to and accompanied the naph- thols and prevented crystallisation.

ISSN:0368-1645    

DOI:10.1039/CT8864900017

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

GLADSTONE AND TRIBE : ALUMINIUM ALCOHOLS. 25 IV.-Aluntiniuin Alcohols. (Part 111.) Alzwviniurn Orthocresglate and its Products of Decomposition by Heat. By J. H. C: LADSTONE, P h .D., F.R.S., and ALFRED TRIBE, F.T.C., Lechrer on Chemistrj in Dulwich College. TEN years ago (Chem. Xoc. J., 1875, 822) we described a reacticn, which was snbsequently extended, and named " The Alumininm Iodine Reaction '' (Proc. Roy. Xoc., 30, 546). By means of this :I number of aluminium-derivatives of the alcohols of the series CtrHzn+ ,*OH, and C,H,,-,*OH have been prepared. In a paper published in the Chemical Society's Transactions, lP82, p. 5, we described the products of the action of heat on several of these aluminium alcohols, and more especially on those obtained from aluminium phenylates and para- and meta-cresglates.The general effect of heat on these aluminium compounds is to produce alumina, more or less of the original alcohol, and the corresponding ether, and sometimes a hydrocarbon; but in the cases of the para- and meta- cresylates, they each furnished, in addition, a beautiful pearly com- pound, crystallising in hexagonal plates of the formula CIaH,,O. These compounds were shown t o be isomeric, and they were named provisionally para- and meta-cresyl ketones.26 GLADSTONE AND TRIBE : ALUMINIUM ALCOHOLS. I n the present paper, we describe the preparation of ort,hocresjlate of aluminium, and the action of heat, upoii it, thus completing the study of the destructive distillation of the cresylic aluminiuiii alcohols. Aluminium 0 y t hocresy 1 ate.The orthocresol employed in this reaction mas obtained from hlessrs. Kahlbaum. It melted a t 31-32', and boiled a t 186". Kekul6 gives 31-31*5" as the melting point, and 185-186" as the boiling point of orthocresol. Aluminium has no action on orthocresol a t ordinary temperatures) and the action is hardly perceptible for a minute or two even a t the boiling point of the compound; but after this the action visibly increases, and proceeds in an increasing proportion, As the action progresses, t8he aluminium foil becomes studded with black specks and patches-doubtless from the uncovering of certain electronegative impurities which, $being in juxtaposition withihe active metal, prohablj accounts f o r the .acceleration in the rate of chemical change already referred to.If a few fragments of iodine are dissolved in the cresol wlien near it's bailing point, and aluminium is added, the decompo- sition takes place a t once and proceeds rapidly. I n order to completely substitiite aluminium for the basic hydrogen in orthocresol, it was heated with an excess of thin aluminium foil until action ceased. The product., while still fluid, was strained through fine wire gauze in order to separate particles of the metal and impurities. On cooling, it solidified to a black vitreous mass, and gave on analysis 8.56 per cent. of aluminium. The percentage of this metal in a compound of the formula ~I~,(C,H,O)~ should be 7.813. The following equation would appear to represent the action :- 6C7H,,0H + 2A1 = Al,(C,H,O), + 3H2.Tlie aluminium orthocresylate readily dissolved in benzene, giving a dark-coloured liquid of a greenish tinge. This colour, and the black colour of the substance itself, we have reason to think, are due to it small quantity of some foreign substance. When the benzene solu- tion is exposed to the air, aluminium hydrate separates, probably from the decomposition of the cresylate by atmospheric moisture. Water and alcohol both decompose it rapidly, aluminium hydrate being formed, and probably the criginal cresol. Action of Heat. 8 68 grams of aluminium orthocresylate, prepared as described, were heated in a flask fitted with a wide, bent tube. I t quickly melted, andGLADSTONE AND TRIBE : -4LUNINIUJI ALCOHOLS. 27 a t a high temperature underwent decomposition, the products being alumina., some carbonaceous and tarry matter, and a dark-brown, viscid distillate.This liquid on cooling was found to contain some aluminium hydrates, but little or no solid organic compound, thus differing froin the corresponding volatile products of the destructive distillation of the para- and meta-cresylates. The distillate was divided by fractionation into three portions-(a) boiling between 140" and 200" ; ( b ) boiling between 200" and 300" ; and (c) boiling above 300". Fraction a.-This portion was a liquid of a light yellow colonr weighing 65 grams. It readily dissolved for the most part in a solution of potassium hydrate, from which it again separated on neutralisation with hydrwhloric acid. The liquid thus separated was dried over calcium chloride.It boiled a t 185-186"; its sp. gr. at 18.2" was 1.049 ; its refractive index for the line A was 1.5373, and for the line H, 1.5851. On heating with aluminium foil and a fragment of iodine, it quickly underwent decomposition with evolution of hydrogen. This fraction, therefore, consisted almost wholly of the original alcohol reconstituted. Fraction Sb.-Tliis portion weighed 200 grams, and was of a yellow- ish-brown colour. It was well shaken with a solution of potassium hydrate, and the residue washed with water and dried over calcium chloride. The liquid obtained was then fractionated some ten times, rejecting a t each distillation the small quantities boiling respectively below 200" and above 300". The product was further fractionated about 20 times, gradually eliminating portious having the greatest range of temperature.In this way a fraction was ultimately obtained (about one-eighth of the whole) which may be supposed to be a fairly pure specimen of the campound, of which ( b ) in a great part consists. The substance thus isolated was a colourless, moderately mobile liquid, which became slightly yellow on exposure to light. Its boiling point was 272-278", and at 24.3" its sp. gr. was 1.047 ; its refrac- tive index for the line A was 1.5638, and for the line H 1.6202. On combustion with oxide of copper and oxygen :- I. 0.238 gram gave 0.7456 gram CO, and 0.1502 gram H,O. 11. 0.870 ,, 0.8449 9, 0.1698 ,, The results expressed in parts per 100 give- I. 11. C .......... 85.43 85.34 H .......... 7.01 6-99 On the determination of its vspour-densitj-, 0.123 gram gave vapour28 GLADSTOKE AND TRIBE : ALUMINUM ALCOHOLS.= in volume to 20 C.C. (corr.). The numbers give 197.8 for the molecular weight of tho substance. Its most probable molecular formula is therefore C,,H,,O. Calc. for 100 parts. Found. Mean. Cid.. .... 168 84-84 85.38 HII. .... 14 7.07 7-00 0 ...... 16 8.09 7.64 (diff.) The odour of this substance resembles that of phenylic ether- namely, that of the geranium lea€,* but fainter, and is similar to the odour of para- and meta-cresyl ethers. We think we are therefore justified in concluding that the substance is also a cresyl ether. It did not crystallise when surrounded by a freezing mixture, from which it would appear not to be the para-modification already described.It seems also to differ in boiling point and sp. gr. from the rnetacresylic ether already described in the same way, and to about the same extent as the ortho- differs from the meta-cresylic alcohol. We conclude, therefore, from this, as. well as from the origin of the compouud, that it is orthocresylic ether. C resy lie a1 coh 01s. Ortho ................ Meta .................. Bciling Sp. gr. nt Specific Specific point. i 18.2". refraction. I dispersion. 185' C. 1 -049 0 *5122 0 -0456 196-202"C.I 1'043 1 0.5116 1 0 *0454 Cresylic ethers. Ortho ................ 272-278' 1 '047 0.5385 O*OZSS(F-Aj Meta ................. 1 284-288 I 1'088 I 0'5386 I 0 * 0266(F-A) It will be observed that each pair of isomeric compounds is practl- cally identical in specific refraction arid dispersion, which giyes great confidence in t,he purity of all four specimens.FV-action c.-This weighed 185 grams, and consisted of a dark- brown, highly viscous fluid. The portions of b boiling above 278" * This resemblance was so marked, that we examined a specimen of pure essential oil of geranium, in the hopes of finding that it contained our creayl ether ; but it did not. We were equally unsuccessful with the conipound knovn as ' I Indian geranium."GLADSTONE AND TRIBE : ALUMINIUM ALCOHOLS. 29 were added to this fraction, and the whole distilled several times; each time collecting, separately, small quantities of liquid which passed over below 280°, and rejecting other small quantities of a tarry non-distillable substance left in the retort.The distillate ultimately obtained was lighter in colour and much less viscous than the original fluid, and on cooling, and still more on standing for 24-48 hours, deposited small quantities of a yellow crystalline substance. I n order t o separate this solid from the liquid, rather more than a n equal volume of alcohol was added, and then enough ether to dissolve the liquid. This mixture wE61 eaibjected to a freezing mixture of ice and salt, yielded a small <iar.tity of the crystalline eubstance, which was removed by f i l t m ~ . ~ . , The alcohol and ether were next separated from the liquid bnbstance by distillation, and the residuum distilled, rejecting, as before, portions boiling below 280" and the tarry non-distillable residue. The distillate obtained was again mixed with alcohol and ether, and subjected to a freezing mixture when another portion of the crystalline compound separated. These operations were repeated some 15-20 times, as long as any quantity of the solid could be recovered.The total amount isolated weighed a little less than 2 grams. In crder to purify this substance, it was dissolved in boiling alcohol and recrystallised therefrom some four OT five times. It was then slowly distilled, and the distillate again crystallised from alcohol. The body was now lemon-yellow in colour, and consisted of fragments of very thin plates. On combustion with oxide of copper and oxygen, it gxve numbers agreeing with the formula C,,Hl40. I n 100 parts. r------h----- 7 Found. Calculated. Carbon .. .... 85-95 85-71 Hydrogen.. . . 6.60 6.66 7.45 7-63 (diff.) -- 100~00 100.00 The experience gained in the purification of some of the compounds described in the secoiid part of this research led us to suspect that the lemon-yellow colour of the substance above referred to was occasioned by its admixture with a small quantity of colouring matter. With the object of separating this impurity, the substance was slowly sub- limed, when brilliant, plates were obtained, but of no very definite form. These were dissolved in hot alcohol, and the solution on cooling deposited diamond- and star-shaped plates free from colour. The quantity of the substance thus purified was too small to allow of further quantitative examination. We have little doubt, however,30 BRTERLEY ON SOME NEW VANADIUM COMPOUNDS.but that its composition is expressed by the number given above, and that it has the molecular formiila C15H110. Whether the body is identical with either of the so-called ketones obtained from the aluminium meta- and para-cresylates, or is an isomeride bearing the same relation to orthocresol as these cornpounds bear to their respec- tive a h h o l s , we have no evidence, physical or chemical, which will enable us to decide, as we attach little or no importance to the difference in crystalline form. It appears from this investigation that the action of heat on the aluminium orthocresylate is generally similar to the action of heat on the para- and meta-modifications. Each of these compounds has yielded its hydrogen-derivative, or alcohol, the corresponding ether, and a crystalline sublimable compound of the formula C,5H,40, together with others not isolated. There are, however, one or two points of difference of some interest. Firstly, the different aluminium compounds have yielded very different quantities of distillate, and, still more, very different quantities of the so-called. ketones. This is shown in the following table of results :- Distillate from Solid from 1000 parks. 14300 parts. Aluminium paracresylate . . . . 609 106 ,, metacresylate . . . . 643 20 ,, orthocresylate.. . . 475 2.5 Another point which may perhaps account for the different amounts of distillate, is the different temperatures required to effect destruc- tive distillation of the several aluminium cresylates. This was especially noticed in the case of the para- and ortho-modifications. Besides probably accounting for the difference in the amount of the product, this observation is of interest as showing that a difference exists i ~ i the stability of these aluminium isomeridcs.

ISSN:0368-1645    

DOI:10.1039/CT8864900025

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

30 BRTERLEY ON SOME NEW VANADIUM COMPOUNDS. V.-On some New Vanadium Compounds. By J. T. BRIERLEY, Dalton Scholar, Owens College. THESE compounds are formed by the following remarkable reaction. If a blue solution of bypovanadic sulphate be mixed with a colourless solution of an nlkaline metavanadat'e, a dark-green liquid will be pro- duced, and if to this a slight escess of caustic soda is added, the colour of the solution quickly changes to a deep black. From this dark-BRIERLEY ON SOME XEW VANADIUM COMPOUNDS. 31 coloured solution, well-defined crystalline salts having a purple or dark- green colour and metallic lustre, can be obtained, in which the condition of oxidation of the metal is intermediate between the t'etroxide, VzOl, and the pentoxide V,05. I have succeeded in preparing five distinct numbers of this group of salts, viz.:- 1. A soluble sodium salt having the composition- 2VzOa,V2O5,2Na20 + 13H20. 2. A soluble potassium salt- 2V2O*,V205,ZK20 + 6H20. 3. An insoluble potassium salt- 2V,0,,4V,O5,5K2O + H,O. 4. A soluble ammonium salt- 2Vz04,2JT,05,(NH4>z0 + 14EzO. 5. An insolubIe ammonium salt- 2T,0,,4V20,,3(NH,),O + 6HjO. Intermediate Oxides. Professor Roscoe observed long ago that when black vanadium trioxide, TzO,, is exposed to the air for many months, it absorbs oxygen and moisture from the air, its colour changing to a pale gi-ass-green. On analysing a sample of such, an oxide which had been freely exposed to the air for a considerable length of time, I found that its composition, as regards its degree of oxidation, corresponds with that of the insoluble potassium and ammonium salts, viz., Vz04,ZV205 + 8HzO.Found. Calculated. Vanadium ........ 45.08 45.49 Oxygen .......... 33.45 33.19 Water. .......... 21.47 21.32 100~00 100~00 -- This oxide, dissolved in d'flute snlphnric aeid and neutralised with caustic potash, yields, when heated, the purple insoluble potassium salt. Another intermediate dark-green oxide, containing an equal number of molecules of tetroxide and pentoxide, may be obtained by the gentle ignition of the ammonium salt, No. 5. This oxide readily absorbs moisture from the air, its composition then being- 3(V204,TT20j) + 8HzO.32 BRIE RLEY ON SOME NEW VANADIUM COMPOUNDS. Found. Calculated. Vanadium. ....... 51-83 51.62 Water .......... 12-25 12.09 100.00 100*00 Oxygen.......... 35.94 36.29 This intermediate oxide, TT,O, can also be obtained in solution by adding strong sulphuric acid to a hot saturated solution of ammonium metavanadate, and then passing sdphur dioxide through the solution until the liquid attains a green colour. After driving off the excess of sulphur dioxide by boiling, the solution was titrated with perman- ganate and found to contain vanadium tetroxide and pentoxide in equal molecular .proportions. The green-coloured solutions thus obtained may also be prepared by suspending freshly precipitated hydrated vanadium tetxoxide in water, adding an insufficient quantity of dilute sulphuric acid t o stand several hours. changing colour from through a11 shades of yellow. t o dissolve it, and allowing the turbid liquid These solutions are very unstable, gradually absorption of a,tmospheric oxygen, passing colour, from dark-green to light-brownish Intermediate Salts. 1.SoluMe Sodium Salt, 2V20~,V,05,2Naz0 + 13R20.-In order to prepare this salt, 12 grams of finely powdered vanadium pentoxide is placed in a flask, an excess of a strong sdlution of sulphur dioxide poured on to it, and the solution heated t o the boiling point, small quantities of sulphuric acid being added from time to time. The deep blue solution thus obtained is then well boiled to expel every trace of sulphur dioxide. Six grams of vanadium pentoxide are separately boiled with an excess of caustic soda until completely dis- solved. The two solations are now mixed hot, and caustic soda added to the dark blackish-green liquid until it is slightly alkaline ; after standing for a short time, acetic aeicl should be added t o the liquid in very slight excess only, as an excess of caustic soda decomposes the green salt.On filtration after boiling, the filtrate contains t8he new salt together with sodium sulphate. As these .two salts possess nearly the same degree of solubility they cannot be separated by crystallisa- tion ; on adding to the cold solution a cold saturated solut.ion of sodium acetate, however, tlie new vanadium salt is precipitated in black shining crystals. These are deposited in large quantity and of con- siderable size if the liquid is heated after addition of the acetate, and then allowed to cool. The crystals shonld be washed with a saturated solution of sodium acetate until the washings are free from sulphuric acid, and the adhering acetate removed by washing with dilute alcoholBRIERLEY ON SOME NEW VANADIUM COMPOUNDS.33 until the latter no longer yields an acid distillate. Finally the crystals are dried over calcium chloride. The sodium salt thug obtained con- sists of black shining plates which, under the microscope, are seen to consist of groups of short hexagonal prisms, and have a sp. gr. of 1.327 at 15" compared with water at 15". A solution of the pure salt, on slow crystallisation, yields hexagonal plates of considerable size, having the form shown in the figure, and an angle between the faces of the pyramid and prism of 133" 45'. The salt is readily soluble in water, yielding a dark blackish-green solution which, on acidification with a few drops of sulphuric acid, instantly changes to a light grass- green, whilst alkalis restore the black colonr, unless an excess be added, when the compound is decomposed with formation of a red- brown solution.The sodium salt is insoluble in strong saline solu- tions-especially in those of the acetates in the cold ; if boiled with potassium or ammonium acetate, purple insoluble salts of these metals are formed. The quantity of the two oxides of vanadium present was ascertained by titration with a standard permanganate solution, care being taken, in the determination of the tetroxide, to use cold solutions, to displace all air by carbon dioxide, and to use well boiled water for dissolving the salt.The total vanadium was estimated by the same method after complete reduction with sulphur dioxide. In order to estimate the alkaline metal, the vanadium was precipitated as lead salt by basic lead acetate, the excess of lead removed by sulphuretted hydrogen, and the sodium weighed as sulphate. For the purpose of determining the water of crystallisation, the salt was heated to redness in a combustion-tube in a current of dry air, and the water collected in a weighed calcium chloride tube. The following are the results obtained :- V8L. XLIX. D34 BRIERLEP OK SOME NEW VANADIUM COMPOUNDS. Found. Calculated. * -, 2V204,V205,2Na20 + I 1st preparation. 2nd preparation. 13Hz0. VzOa . . . . 37.6'7 36.80 38.12 V20, . . . . 21-19 21.00 20.88 H20 .. .. 26.05 25.34 26.80 NhO... . 14-15 13.88 14.20 99-06 97-02 100~00 -- 2. Soluble Potassium Salt, 2V204,V205,2K20 + 6H20.-In order to prepare this salt, 20 grams of vanadium pentoxide were reduced by sulphur dioxide, and 10 grams also were converted into potassium metavanadate, the filtered solutions being mixed and caustic potash added to slight alkalinity. The resulting greenish-black liquid was then heated to the boiling point, filtered, mixed with a cold saturated solution of potassium acetate, and the mixed liquids evaporated on the water-bath to a small bulk. On cooling and standing, a mass of small dark crystals separated which, under the microscope, were seen to consist of imperfectly formed octohedrons having a purple colour, mixed with other dark-green four-sided crystals.The mixed crys- talline mass was then well washed on a filter with hot water, which dissolved the greenish-black crystals, leaving the purple insoluble salt behind. The dark-green filtrate was, as before, mixed with a concen- trated solution of potassium acetate, heated until the separated crys- tals redissolved, and the solution left to cool. On standing, fine greenish-black crystals were deposited from which all trace of potas- sium sulphate was removed by continued washing with weak alcohol. This compound has a sp. gr. of 1.389 at 15", compared with water at 15". Analysis of this salt gave the following:- Found. 7-- Calculated. 1st 2nd preparation. 2VzO,,V205,2K20 preparation. r--- 7 + 6H20. VzOa . . .. 42.02 40-83 40.16 41.04 VzOj . . . . 23.54 23.90 22.58 22.48 H,O .. . . 11-11 12.82 13.84 13-31 K,O , . . . 21.04 21.21 21.58 23.17 97.71 98.76 98-16 100~00 - -- -- Preparation No. 1 contains 5 mols. H20. 3. Insoluble Potassium Salt, 2Vz04,4V204,5K20 + H,O.-The purple insoluble salt above mentioned can be easily obtained pure from the mdtber-liquors of the sodium salt. This dark-green solu-BRLERLEY ON SOME NEW VANADIUM COMPOUNDS. 35 tion containing sodium acetate and sulphate is heated and filtered hot, to the hot liquid some solid potassium acetate is added, and the whole is well boiled. Small crystals having a metallic lustre soon form on the surface of the liquid, and, if the boiling be continued, the whole of the soluble sodium salt, may thus be converted into the insoluble potassiam compound. The sp.gr. of this salt is 1.213 at 15" compared with water at 15". In order t o determine the potas- sium in this insoluble salt, it was oxidised with strong nitric acid, and the pentoxide converted into the ammonium salt ; this was then precipitated with lead acetate as before, and sulphate. 7:- - Found. 1st preparation. 2nd preparation. v204 . . . . 20.75 22.81 vzo5 . . . . 47.47 45.98 KzO .. .. 28.24 29.83 H20 .. .. 2.26 1.17 98.72 99.78 -- -- the alkali weighed as Calculated. 2VzO4,4V2O,,5K2O + H20. 2 1.48 47.05 30-32 1.15 100~00 The amount of water in preparation No. 1 corresponds with 2 mols H20, whilst that in No. 2 agrees with 1 mol. H20. 4. Soluble Ammonium Salt, 2V2O4,2V2O,, (NH4),0 + 14H20.-This salt is formed by boiling vanadium pentoxide with ammonia until solution takes place, reducing two-thirds of the resulting solution to V20,, mixing this with the anreduced third, and adding ammonia to slightly alkaline reaction. A dark-green solution of t,he above ammonium salt is thus formed; this cannot be boiled, as the salt is thereby converted into the insoluble compound. By adding acetic acid t o the solution until faintly acid, and then alcohol, and allowing the mixture to stand after well shaking, a black crystalline precipitate separates.The supernatant liquid is decanted, and the precipitate thrown on a filter, and washed with a mixture of equal volames of alcohol and water until free from snlphuric acid. The salt thus obtained is then dried over calcium chloride. I t consists of greenish- black crystals which are very unstable, readily absorbing oxygen from the air.In order to determine the ammonia, the salt placed in a platinum boat was heated in a combustion-tube, and the ammonia collected and weighed as platinochloride. Analysis gave :-36 BRIERLEY ON SOME NEW VANADIUM COMPOUNDS. Found. 1st preparation. Calculated. VZO, . .. . 33.20 33.23 V20, . . . . 35.62 36.43 (NH4jz0. 5.67 5.19 H,O*. . . . 25.51 25.15 7 00.00 100~00 - * Water by difference, 5. Insoluble Ammolzium Halt, 2VzO~,4Vz0,,3(NH,jz0 + 6Hz0.- The foregoing soluble salt is readily converted into this insoluble compound by adding ammonium chloride to its solution rendered alkaline by ammonia, and gently heating the liquid for some time. Small purple crystals having a metallic lustre separate out-first on the sides of the vessel, and afterwards on the surface of the hot liquid. I t is not necessary for this purpose to prepare the pure soluble ammonium salt, as the dark-green liquid obtained by mixing equal parts of solutions of VZO, and of ammonium metavanadate readily yields this salt when rendered alkaline with ammonia and lieated. The crystalline precipitate is well washed with hot water until it is seen under the microscope to be perfectly homogeneous. Ib crystallises in small purple octagonal plates, of a metallic lustre, and yields a brown powder. Its sp. gr. at 15" is 1,335 compared with water at 15". Analysis gave :- Found. 7- - Calculated. preparation. -*- + 6Hz0. 1st 2nd preparation. 2V20,4V20,3 (NH&O Vz04 . . . . 25.64 24.77 25.15 25.09 VZO, . . . . 55.48 55.29 55.42 55.01 (NH4)ZO.. 11.68 12.40 11.51 11.76 HzO*. . . . 7.20 7.54 7.92 8.14 100~00 100*00 100*00 100~00 --- It Water by difference. In concluding my paper, I must thank Mr. Harden, of Owens College, for kindly confirming several of my results.

ISSN:0368-1645    

DOI:10.1039/CT8864900030

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

37 TI.-On the Vapour-pressures of Mercury. BY WILLIAM RAMSAY, Ph.D., and SYDNEY YOUNG, D.Sc. IN a recent paper in the Transactions (1885, 640-657), we described a method by which constant known temperatures could be maintained with great exactitude. In the tables which conclude t.hat papel-, Regnault's determinations of the vapour-pressures of mercury have been accepted as correct; on revision, however, they appear to be by no means so trustworthy as most of his work. In vol. 26 of the Mhnoires de l'dcadeinie Regnault quotes results described in vol. 21, p. 502, and uses these results for determining the formula devised by him to express the relation between temperature and pressure at low temperatures. On reference to vol. 21, it is evident from Regnault's own remarks, that he placed little confidence in the accuracy of his results.His words are as follows :-" Ces deux series d'exp8riences diff &rent notablement quand on compare les valeurs relatives qu'elles donnent pour leu forces Qlastiques de la vapeur mer- cnrielle; mais les differences absolues que l'on trouve entre les forces Qlastiques sont reelement tri?s-petites, et de l'ordre de l'incertitude des observations. Les experiences prQc6dentes su ffisent neanmoins pour montrer que la tension de la vapeur de mercure 8 LOO" est d'environ 0.5 mm. ; et qu'8 la tempkraturc de 50", elle s'Ql&ve B peine 8 0.1 mm. Elle est donc B peu prhs negligeable au dessous de 50"." These words refer to temperatures below 100". In a footnote he proceeds-" J'ai fait quelques determinations de la tension de vapeur du mercure & des tempQratures plus QlevBes, en chauffant le ballon dans un bain d'huile.Vers 200" les exphiences sont devenues Bvidemment fautives, par suite de la distillation du mercure. Quoiqu'il en soit, voici les nombres que j'ai obtenu : il conuient de ne les regaieder pue comme des arnroximations." (The italics are ours.) His numbers then follow. They are the results of eleven readings, and these are all which he gives at temperatures below 250". He also refers in vol. 26 to four determinations given in vol. 21, p. 230, made at the boiling point of mercury under atmospheric pressure, for the purpose of comparing his mercurial and air thermometers. His method in this instance differed essentially from the other methods employed ; i t consisted in heating an air reservoir terminating in a capillary tube in the vapour of mercury boiling under atmospheric pressure, sealing the tube, and when cold, breaking the point oE under mercury, and measuring the contraction of the air.These four experiments gave fairly concordant results, but owing to an evident misquotation in vol. 26, it is not38 RAMSAY AND YOUNG ON THE quite certain to what pressures his symbols 7~ and ho refer, as from h the mean of the four determinations would give the pressure '767.43, while from h, 765.29 is the mean. But as the temperatures them- selves differ by nearly 2" at the satme pressure, this slip is an unimpor- tant one. At higher pressures, Regnault employed a large iron still, containing 50 kilos. of mercury, into which dipped an iron tube con- taining the air thermometer.By applying pressure from an air reservoir, the boiling point of the mercury was regulated and observed. He states that the temperature was observed as soon as it had become constant, and the observations were repeated until it began to rise, by which time the greater part of the mercury had distilled over. He directs attention to the fact that, using this method, the temperatures are those of the boiling liquid, and not of the vapour. During distillation, the noise of the bumping was com- pared to blows of a hammer on an anvil. That these results cannot be relied on is shown by those referring to the atmospheric pressure, where a fall of 7.4 mm. in pressure corresponds to a rise of tempe- rature of 1.86" ; and the mean temperature (about 355.4") by no means corresponds with that obtained by the method previously described (358~5~).It is obvious that good results cannot be anticipated under such conditions. The importance of a correct knowledge of the vapour-pressures of mercury is evident, when it is considered that they enter into all calm lations of the determinations of vapour-pressures of liquids by the usual method at high temperatures; and that they must be allow ed for in determining vapour-densities by Hofmann's apparatus. Moreover, it is probable that thermometers based on a knowledge of the vapour-pressure of mercury will become available for accurate determinations of high temperatures. Owing to the discovery of certain relations between the vapour- pressures of different substances, which are described in the Philo- sophical Magazine for December, 1885, and January, 1886, we have been able, with small expenditure of time and labour, to obtain results which we think will be generally accepted as correct. Before describing the experiments, a short description of the generalisations may render the process intelligible.Although some of these apparently have little connection with the matter in question, yet from thermo- dynamical considerations, they are so interlaced, that we deem it advisable to state them all. For detailed description and proof of the following statements, we would refer to the articles already mentioned. 1. The amount of heat required to produce unit increase of volume in the passage from the liquid to the gaseous state at the boiling point under normal pressure, is approximately constant for all substances.VAPUUR-PRESSURES OF MERCURY.39 2. If the amounts of heat required to produce unit increase of volume in the passage from the liquid to the gaReous skate be com- pared at different pressures for any two bodies, then the ratio of this amount at the boiling point under a pressure pl to the amount at another pressure, p2, is approximately constant. 3. It appears probable, from the few data at present available, that if a diagram be constructed in which the ratios at the same pressure between the heats of vaporisation of two liquids, at various pressures, the same for both, form the abscissq and the absolute temperatures of one of the two liquids, corresponding to those vapour-pressures, form the ordinates, then the points representing the relations between these ratios and the absolute temperatures will lie in a straight line, 4.The products of the numbers representing the absolute tempe- rature into the increase of pressure per unit rise of temperature at those temperatures, are approximately the same for all substances at the same vapour-pressure; but the differences are real and are not due to error of experiment or calculation. 5. The rate of increase of this product with rise of pressure is very nearly constant for all bodies. 6. The deviation from constancy presents the following relations :- If a diagram be constructed in which the ratios at definite pressures of the product referred to in (4) for any two substances be made the abscisss, and the absolute temperatures of one of the bodies at corre- sponding vapour-pressures be made the ordinates, then the points representing the relations of these two quantities will fall in a straight line.7. A relation exists between the ratios of the absolute temperatures of all bodies, whether solid or liquid, whether stable or dissociable, which may be expressed in the case of any two bodies by the equation R’ = R + c(t’ - t ) ; where R is the ratio of the absolute tempera- tures of the two bodies, corresponding to any vapour-pressure, the same for both ; R‘, the ratio at any other pressure, again the same for both; c, a constant, which may equal 0 or a small plus or minus number ; and t’ and t the temperatures (absolute or centigrade) of one of the bodies corresponding to the two vapour-pressures.When c = 0, R’ = R, or the ratio of the absolute temperatures is a, constant at all pressures; and when c > 0, or c < 0, its value may readily be determined either by calculation, or graphically by repre- senting the (absolute) temperatures of one of the two bodies as ordinates, and the ratio of the absolute temperatures at pressures corresponding to the (absolute) temperatures of that body as abscissae. It is found in all cases that points representing the relation of the ratio of the absolute temperatures of the two bodies to the (absolute) temperature of one of them fall in it straight line.40 RAMSAY AND YOUNG ON THE On comparing such relations for different substances of which the vapour-pressures had been accurately determined, in twenty-three cases, this relation was found to hold absolutely ; for on calculating by means of this ratio the absolute temperatures of these substances corresponding to given pressures, the differences observed between calculated and experimental results fall well within the limits of ex- perimental error.On using Regnault’s determinations of the vapour- pressures of mercury, the case was different. Here a, curve, instead of a straight line, was obtained. Now it is evident that if satisfactory proof can be given that certain temperatures, sufficiently far removed from each other, when compared with the ratios between these absolute temperatures of mercury and some other liquid of known vapour-pressure, e.g., water, give points which fall in a straight line, the value of c is calculable, and as a consequence, the whole vapour- pressure curve of mercury.Mercury also formed the only excep- tion to statements ( 5 ) and (6). The temperatures chosen were-(1) the boiling point of methyl salicylate under atmospheric pressure ; (2) the boiling point of bromonaphthaIene under a pressure of 612.8 mm.: (3) the same under a pressure of 756.2 mm. ; (4) more reliance is to be placed on the boiling point of mercury under atmospheric pressure, deter- mined by Regnault, described in vol. 21 of the Meinoires, as the method he adopted seems to deserve greater confidence than his later method; and the mean of his four results may be taken as fairly correct ; ( 5 ) the boiling point of sulphur under atmospheric pressure, determined by Regnaulf.For the accuracy of our knowledge of the first three of these temperatures reference must be made to the Transactions (1885, p. 640 et seq.). Regnault determined the vapour-pressures of sulphur, using an apparatus similar to that with which he determined the vapour- pressures of mercury. He did not find it necessary to fill the still with liquid sulphur, and the boiling took place quietly, without bumping. He appears to place more reliance on his determinations of the vapour-pressures of sulphur than on those of mercury; and this conclusion is borne out by our experience ; for on comparing the vapour-pressures of sulphur with those of carbon disulphide, the ratios of the absolute temperatures form with the absolute tempera- tures of carbon disulphide, or sulphur, a straight line, when con- sidered as described in statement (7), and the results agree remark- ably well with statements (4), ( 5 ) , and (6).It is obvious that the temperature of the boiling point of sulphur under atmospheric pressure really amounts to an indirect reading of Regnault’s air thermometer ; and for the above-mentioned reasons we believe that the temperature in this case is correct.VAPOUR-PRESSURES OF MERCURY. 41 Closed limb of apparatus. -- For the determinations of the vapour-pressure of mercury, the process adopted in our late experiments was employed; and the apparatus is represented in a woodcut on p. 643 of the Transactions for 1885, modified as described on p. 651.A description is therefore unnecessary here. (1.) The detailed results are as follows :- Open Papour apparatus. mercury. limb of A. at A oo. Pressure a at oo. 2zz: pressure of Mean. ------------ 703.8 704.2 '701.1 704.3 704.5 - 0.7 -0.7 34.9 35-1 705.0 - 0.8 -0.8 35'2 35 -2 '708'0 -6.9 -6.65 - 41 -05 704.1 + 0.2 +0*2 34.1 34.2 34.45 NOTE.-TWO gauges and barometers were used, lettered A and B respectively. The mean reading of the two was taken. The pressure under which the methyl salicylate boiled was 746.95 mm. (reduced to 0")) and the corresponding temperature 222.15". The mean observed vapour-pressure of mercury at this temperatnro is accordingly 34.4 mm. (2) and (3.) The detailed results of our observations with bromo- naphthalene are given in our previous paper (Eoc.cit.). The numbers are as follows :- Pressure of bromo- Pressure of mercury Temperature from naphthalene vapour. vapour. Regnault's data. '756.2 mm. 157.15 mm. 280.6" 612-8 ,, 124.35 ,) 270.35". These temperatures are calculated from Regnault's formula for the vapour-pressures of mercury, and were made use of in determining the position of the curve representing the relations of temperatiire to pressure for bromonaphthalene. It was noticed at the time that this curve would not pass through both points representing the tempe- ratures of the bromonaphthalene; and as other readings had been taken with a mercury thermometer previously compared with an air thermometer, confirming the lower temperature, it was judged right to construct the curve on this basis.Eeading then from the curve we adopted, the higher temperature becomes 280.2", instead of 280.6". The justice of this correction has since been confirmed by a study of the relations between the absolute temperatures of bromonaphthalene and water. (4.) The relations obtained for mercury at the atmospheric pres-42 RAMSAY AND YOUNG ON THE sure by Regnanlt have already been considered. They are as follows :- Temperature. HI. Ho. 358-46" 769.59 mm. 770.27 mm. 357.48 768.40 ,, 766.76 ,, 359.27 768.08 ,, 766.11 ,, 358.68 763.65 ,, 758.02 ,, H, and El, are the barometric heights at the moment of closing the air thermometer, and of breaking the point off under mercury ; but it is uncertain from the text which symbol is to be used for the one and which for the other.The mean temperature is 358.47"; the mean of h, is 767.43 mm. ; and the mean of h,, 7'65.29 mm. (5.) In order to determine the vapour-pressure of mercury at the boiling point of sulphur, a, new form of apparatus was employed, which is shown in the accompanying figure. The apparatus AA' is constructed of barometer tubing of small bore. At the end A is blown a bulb so adjusted as regards size that the volume of the bulb is approximately equal to that of the hori- zontal portion of the stem, and when cold, containing mercury to the mark a. B is a vessel containing sulphur ; in one experiment this was a flask, as shown ; in the other, a wide test-tube. On applying heat, the sulphur vapour could be caused to completely surround the bulb A. The mouth of the flask was loosely closed with cotton-wool, to prevent escape of sulphur Tapour, or the formation of air currents. C is a jacketing tube in the form of a Liebig's condenser, whereby the horizontal portion of AA' could be maintained at a constant known temperature, shown by the thermometer D.The tube AA' was first graduated in millimetres from about a to the end ; it was then exhausted, filled with mercury, and repeatedlyVAPOUR-PRESSURES OF MERCURY. 43 boiled out under atmospheric pressure, until air bubbles ceased to come off from the glass. The end A' was next drawn out to a capillary tube, and was exhausted repeatedly with a Sprengel's pump, dry air, which had stood in contact with phosphorus pentoxide for some time, being admitted after each exhaustion.While the capillary tube was still connected with a, small drying tube of pentoxide, the tube AA was placed in a vertical position in a wide tube through which a current of water of constant known temperature ran ; the capillary end of AA' projected just above the surface of the water. The temperature of the water and the atmospheric pressure were then read, and the capillary was sealed, the position of the mercury in the tube being noted at the same moment. From these data, the volume of the air at known temperature and pressure was subsequently ascertained. The apparatus was then arranged as shown in the figure, and the sulphur made to boil. The ebullition took place quietly and easily, and thin deposit of liquid sulphar on the sides of the flask made it certain that the vapour was not superheated.Had this not been the case, the bulb would have been surrounded with asbestos. When the mercury in the bulb had become hot, it was driven by the pressure of its vapour nearly out of the bulb, and was forced along the horizontal portion of the tube, as fa.r as 6, compressing the air. The position of b was then read, and the temperature of the water in the jacket C was noted. The barometric pressure was also read, so as to determine the temperature of the sulphur vapour. When cold, the tube was broken close to the bend, and calibrated by weighing with mercury. The pressure of the mercury vaponr in the bulb is equal to that of the air in the gauge, plus the pressure of a column of mercury equal to the vertical distance between the level of the mercury in the bulb and that in the horizontal portion of the tube, this column being corrected for temperature. The detailed results are as follows:- I.(1.) Air at atmospheric pressure :- Pressure Temperature. (reduced to 07. 16.20" 743.7 mm. Volume. 0.91690 C.C. (2.) Air at high pressure :- Temperature. Volume. 16-60' 0.24440 C.C. Pressure calculated from above data, 2794.0 mm. (3.) Column of mercury heated to 450°, 57 mm. These reduced to 0" become 52.8 mm. and 50.1 mm. respectively, 9 , >, ,, about loo", 51 mm.44 RAMSAY AND YOUNG ON THE The total pressure of the mercury vapour is therefore 2794 + 52.8 + 50.1 = 2896.9 mm. (4.) The barometric pressure when the sulphur wits boiling was 742.6 mm. (reduced to O O ) , and the corresponding temperature was 447.0°.11. (1.) Air at atmospheric pressure :- Temperature. Pressure. 16.24" 752.3 mm. Volume. 0.53546 C.C. (2.) Air at high pressure :- Temp era ture . Volume. 15-40" 0.14385 C.C. Pressure calculated from above data, 2791.0 mm. (3.) Column of mercury heated to 450", 52.5 mm. 9 9 7, ,, about loo", 66.0 mm. These reduced to 0" become 48.6 mm. and 64.9 mm. respectively. The total pressure of the mercu1.y vapour is therefore 2791 + 48.6 + 64.9 = 2904.5 mm. (4.) The barometric pressure when the sulphur was boiling was 754.4 mm. (reduced to O O ) , and the corresponding temperature was 448.0". The whole of these results are shown in the following table :- Temperature (centigrade). 222 * 15" 270 '30 280'20 358.46 357 -48 359 *e7 358.68 447'0 448 - 0 Temperature (absolute).495 * 15" 543 - 30 553 -20 631.46 630 -48 632 '27 631 * 68 720'0 721'0 Pressure. Absolute temperature of water a t pressure p . 304 * 5" 329.2 334.2 373.35 373'37 373 *30 373.25 373 * 29 373'22 373 -13 372 * 93 415'26 415 * 36 Ratio of absolute temperature. 1 * 6262 1 -6504 } ;:::: 1 * 6889 1 * 6892 1 - 6938 1 * 6941 1 -6930 1.6938 1 -7338 1 * 7359 The accompanying diagram, in which the ratios are represented as abscissa, and the absolute temperatures of mercury in one case and of water in the other are the ordinates, represents the results obtained.VAPOUR-PRESSURES OF i1IIERCURY. 45 The ratios calculated from Regnault’s determinations give the dotted curve with absolute temperatures of water as ordinates. It will be noticed that in each case a straight line can be drawn through all the points.The value of c, if the temperatures of mer- cury are chosen as ordinates, is 0.0004788; if those of water are chosen, it is 0.0009792. The calculations of the vaponr-pressures of mercury from these two constants give slightly different results ; but the difference within the limits of temperature given in the ensuing tables is unimportant, although at higher temperatures it might become considerable. It was more convenient to employ the constant derived from the abso-46 RAMSAY AND YOUNG ON THE lute temperatures of mercury; and we now proceed to show the method of calculation. A point was read from the straight line, giving the ratio at any one temperature. The absolute temperature of water was calculated from the ratio.The vapour-pressure of water corresponding to this temperature is the same as that of the mercury, inasmuch as the ratios refer to equal pressures. Thus, at an absolute temperature of mercury of 50b", the ratio as read from the line was 1.6331. The 508 1.6331 absolute temperature of water was therefore ~ = 311.06". The vapour-pressure of water at 311-06", ascertained from Regnault's tables is 49.466 mm., and this is therefore the vaponr-pressure of mercury at an'absolute temperature of 508". The ratios corresponding to other absolute temperatures of mercury were calculated from the equation R' = R c(t' - t), the value of R beiig 1.6331, as given above. Of course other ratios might have been read from the straight line; but it seemed better to employ the factor 0.0004788 in the calculation.The data employed and the results of this calculation are as follows :- Temperature (centigrade). 135" 140 145 150 155 160 165 170 175 180 185 190 195 200 205 210 215 220 225 230 235 240 245 250 255 260 Absolute temperature of mercury. 408" 413 418 423 428 433 438 443 448 453 458 463 468 4'73 478 483 488 493 498 503 508 513 518 523 528 533 Ratio. 1 - 585220 1 * 587614 1 -590008 1 * 592402 1 * 594796 1 -597190 1.5995% 1 -601978 1 * 604372 1 *606766 1 * 609160 1.611554 1 - 613948 1 * 616342 1 * 618736 1 * 621130 1.623524 1 -625918 1.628312 1 * 630706 1.633100 1 - 635494 1*63'7888 1 - 640282 1 - 642676 1 -645070 Absolute temperature of water. 257 -38' 260.14 262.89 265 * 64 268.37 271 - 10 273 - 82 276 *53 279 -24 281 - 93 284.62 287 * 29 289 *98 292 -64 295 * 30 297 * 95 300.59 303 * 22 305.84 308 -46 311 *06 313.67 316 *26 318 -85 321.42 324.00 Vapour- pressure.1.409 mm. 1.754 ,, 2.172 ), 2-680 ), 3.28'1 ,, 4.013 ,, 4.879 ), 5.904 ), 7.116 ,, 8.535 ,, 10*204 ,, 12,137 ), 14.403 ), 17-015 )) 20 *028 )) 23.482 ), 27-447 )) 31-957 ,, 37'083 ), 42.919 ,, 49.466 ,, 56.919 ,, 65.241 ,, 85.010 ), 96-661 ), 74-59s ,)VAPOUR-PRESSURES OF MERCURY. Temperature (centigrade). 265" 270 275 280 285 290 295 300 305 310 315 320 325 330 335 340 345 350 355 360 365 370 375 380 385 390 395 400 405 410 415 420 425 430 435 440 a 5 450 455 460 465 470 475 480 485 490 495 500 505 510 515 520 Absolute temperature of mercury. 538" 543 548 553 558 563 568 573 578 583 588 593 598 603 608 613 618 623 628 633 638 643 648 653 658 663 668 6'73 678 683 688 693 698 703 708 713 718 723 '728 733 738 743 748 753 758 763 768 773 778 783 788 793 -- Ratio.1 - 647464 1 - 649858 1 - 652252 1 * 65 4646 1 * 657040 1 -659434 1.661828 1 *664222 1 - 666616 1 *669010 1 -671404 1 - 673798 1 -676192 1 - 678586 1 * 680980 1 -683374 1 - 685768 1 - 688162 1 * 690556 1 * 692950 1 * 695344 1'697738 1.700132 1 * 702526 1 * 704920 1 * 707314 1 - 709708 1 - 712102 1 * 714496 1*716890 1 * 719284 1 * '721678 1 724072 1 * 726466 1 "728860 1- 731254 1 - 733648 1 ' 736042 1-738436 1 * 740830 1 * 743224 1 * 745618 1 * 748012 1 - 750406 1 * 752800 1 * 755194 1 757588 1 759982 1 762376 1 -764770 1 -767164 1 - 769558 Absolute temperature of water. --- 326.55' 329-11 331.66 334.21 336.75 339.28 341 -80 344 - 31 346 - 81 349-31 351 *80 354 -28 356 -75 359.22 361 - 68 364.14 366 -59 369 - 04 371.48 373 * 91 376.33 378 -75 381.16 383 *56 385.95 388.34 390 - 72 393 * 09 395 -45 397 * 81 400.16 402 * 50 404.85 407 * 19 409 * 51 411.83 414.15 416.47 418'77 421-07 423 * 36 425 * 65 427 - 92 430-18 432 - 44 434 * 70 436 * 96 439 -21 441 * 45 443 *67 445 - 90 448'12 Vapour- pressure.-- 109.556 mm. 123.905 ,, 139-802 ,, 157.378 ,, 176-733 ,, 197'982 ,, 221'251 ,, 246'704 ,, 274.443 ,, 304,794 ,, 412'249 ,, 454.277 ,, 499.656 ,, 548.715 ,, 601.583 ,, 658-515 ,, 719-772 ,, 785.107 ., 855-223 ,, 930.335 ,, 1010*47 ,, 1096-22 ,, 1186.67 ,, 1253.71 ,, 1386'60 ,, 1495.60 ,, L611-19 ,, 1733.79 ,, L863-36 ,, 2145.57 ,, 3298-80 ,, 3459-41 ,, 3628.79 ,, 3807'53 ), 3996.06 ,, 3192.69 ,, 3399.50 ,, 3616.22 ,, 3843.68 ,, b080.10 ), E327.14 ,, E856-74 ), 5139.89 ,, 5434.99 ,, 5741.86 ,) jO59-16 ,, j391-49 ,, 336.60 ,, 337'753 ,, 373.528 ,) 2000*21 ), E585-95 ), In calculating pressures below 4.6 mm., Regnault's formula48 RAMSAY AND YOUNG ON THE expressing the relation between t,emperature and pressure of water between 0" and 100" has been employed.As it was impossible to calculate the vapour-pressure of mercury below 135", owing to our ignorance of the vapour-pressure of water at low temperatures; and as a knowledge of the lower vapour- pressures of mercury is necessary, the constants of a formula of the form employed by Regnanlt in calculating the vapour-pressures of water below 0" were calculated. log p = a + bat.The formula is- I n calculating this formula,, the temperatures and pressures made use of in determining the value of the constants were as follows :- Temperatures. Pressures. 160" 4.013 mm. 220 31.957 ,, 280 157.378 ,, The constants are therefore- a = 4.493745 log b = 0.5899797 b = - 3.890276. t = t o c. - 160 log a = 1.9980929. The table which follows shows the vapour-pressures of mercury at temperatures below 160°, calculated as above described. Temp. 4.0' 50 60 70 80 90 Pressure. 0.008 mm. 0.015 ,, 0-029 ,, 0.052 ,, 0.092 ), 0.160 ,, Temp. 100" 110 120 130 135 --- Pressure. -- 0 *Z70 mm. 0-445 ,, 1.137 ,, 1.419 ,, O''r19 )) Temp. 140' 145 150 155 160 --- Pressure. 1 963 mm. 2.181 ,, 2.684 ,, 3-289 ,, 4,013 ,, As these numbers are extrapolated from 220", it appeared neces- sary to control them by a determination at a lower temperature.The vaponr-pressure of mercury was therefore directly determined at the boiling point of chlorobenzene under a pressure of 754.2 mm., corre- sponding to a temperature of 131*8", by the method employed for its determination at the boiling point of methyl salicylate. Twenty- three readings were taken, the level oE the mercury in the vapour- pressure tube being altered from time to time. The mean result was 1-58 mm.; the mean probable error was 0.14 mm. The calculat,ed pressure is 1.24 mm. ; but we think that the experimental result is asVAPOUR-PRESSURES OF MERCURY. 49 close as can be expected from the very small amount to be measured, and we regard it as a sufficient confirmation of the accuracy of the table given above.At 132" Regnault's pressure is 2.30 mm., and this is manifestly too high. In order to afford data whereby the temperatures of mercury vnpour used as a jacket may be easily ascertained froin the read pressure, we append a table of the vapour-pressures for each degree centigrade. This table is to be substituted for the one published in the Trans., 1885, p. 656. The results given were smoothed by the method of differences, and each degree was calculated by differences. Tmp. -__- 2'7(J0 271 272 2 73 2 74 275 276 277 279 290 281 282 283 285 286 287 283 289 290 291 292 293 294 295 296 29 7 298 299 3G0 278 284 Pressure. 123 '92 mm 126.97 ,, 130.08 ,, 133-26 ,, 136.50 ,, 139.81 ,, 143.1% ,, 146.61 ,, 150.12 ,, 153 *70 ,, 1.57 -35 ,, 161.07 ,, 164.86 ,, 168.73 ,, 172.67 ,, 176.79 ,, 180-88 ,, 185.05 ,, 189.30 ,, 193.63 ,, 198*0% ,, 202.53 ,, 207.10 ,, 211 .76 ,, 216.50 ,, 221.33 , J 226.25 ,, 231.25 ,, 236.34 :, 241.53 ,, 246.81 ,, Temp.__-I- 301" 302 303 304 305 306 31 17 308 309 310 31 1 312 313 314 315 316 317 318 3i9 320 32 1 322 323 324 325 326 327 329 330 331 328 Pressure. -- 252.18 mm 257.65 ,, 263.21 ,, 268.87 ,) 274.63 ,, 280.428 ,, 286.43 ,, 298,66 ,, b04.93 ,, 311.30 ,, 317'78 ,, 324.37 ,, 331 *08 ,, 337.89 ,, 344.81 ,, 351.85 ,, 366.28 ,, 373.67 ,, 381 *18 ,, 388.81 ,, 396.56 ,, 404.43 ,, $12.44 ), $20.58 ,, $28 83 ,, 437.22 ,, $34.41 ,, $63.20 ,, 292.49 ,, 359.00 ,, kb3.75 ,, Temp. --- 332' 333 334 333 336 337 333 339 3 10 3 41 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 Pressure.472 -12 mm. 481.19 ,, 490 40 ,, 509.22 ,, 518.85 ,, 528.63 ,, 538'56 ,, 548.64 ,, 558.87 ,, 569.25 ,, 579 *78 ,, 590.48 ,, 601.33 ,, 612 .34 ,, 623'51 ,, 634-85 ,, 646.36 ,, 658.03 ,, 669.86 ,, 681.86 ,, 694.04 ,, 706'40 ,, 718.94 ,) 731 -65 ,, 757.61 ,, 770 -87 ,, '784'31 ,, 499.74 ,, 744.54 ,, The result of this investigation, we venture to think, furnishes a most convincing proof of the justice of the generalisations on which it is based. E50 JAMES : ACTION OF PHOSPHORUS PENTACHLORIDE ADDENDUM. Since reading the above paper, Professor Herbert McLeod has kindly directed our attention to two memoirs on the same subject, one by Hagen ( A m . Phys. Chem., N.F., 16, SlO), and one by Hertz (ibid., N.F., 17,193). The methods employed by both these experimenters in measuring temperature are open to criticism. Hagen's experiments appear to have beea conducted'with very great care ; but the results are abnormal, f o r he finds a pressure which must be greatly in excess of the truth a t low temperatures. Hertz employed a method analo- gous to ours, and the closeness of the coincidence between his results and ours is remarkable, when it is remembered that ours are extra- polated from measurements at much higher temperatures, the correct- ness of which was confirmed by their agreement with the relations mentioned in our paper. We think it advisable to reproduce their numbers at low temperatures, comparing them with those of Regnault and ourselves. Temperature. 0" ........... 10 ............ 20 ............ 30 ............ M ............ 50 ............ 60 ............ 70 ............ 80 ............ 90 ............ 100 ............ 120 ............ 140 ............ 160 ............ 180 ............ 200 ............ 220 ............ Regnault. --- 0.02 mm. 0.0268 ,, 0'0372 ,, 0'0630 )) 0.0767 ,) 0.1120 ,, 0.1643 ,, 0'2410 ,, 0.3528 ,, 0'5142 ,, 1'5341 ,) 0 -7455 ,) 3.0592 ,, 5'9002 )) 11*000 )) 19.90 ,, 34-70 ,, Hagen. 0 *015 0-018 0 '021 0 *026 0 *033 0 '042 0 -035 0 074 0'102 0 9 4 4 0 '210 - - - - - - Hertz. -- 0 *00019 0 *00050 0 *0013 0.0029 0 * 0063 0 '013 0.026 0 -050 0.093 0 -165 0 *285 0.779 1 *93 4 '30 9 *23 18 '25 34 -90 Ramsay and Young. - - - __ 0 *008 0 -015 0 -029 0 -052 0 -092 0.160 0.270 0 *719 1 *763 4'013 8.535 17.015 31 957

ISSN:0368-1645    

DOI:10.1039/CT8864900037

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

50 JAMES : ACTION OF PHOSPHORUS PENTACHLORIDE VIL-Action of Phosphorus Pentachloride on Ethylic D i e t k ylaceto- acetate. By J. WILLIAM JAMES, University College of South Wales, Cardiff. TEE action of phosphorus pentachloride on ethylic acetoacetate was first carefully investigated by Geuther (Jeiznische Zeitschrift, 4, Heft 4), who found that the ethoxyl-group was displaced by chlorine, giving rise t o the chlorides of two isomeric chlorocrotonic acids.ON ETHYLIC DIETHYLACETOACETATE. 31 Some years later, Rucker (Annalen, 201, 5 6 ) submit,ted an ethereal monalkylacetoacetate to the same treatment, and again found that the ethoxyl of the carboxyl-group was displaced by chlorine, the product being the chloride of a single monalkylchlorocrotonic acid. Judging from these results, it' was to be expected that the action of phosphorus pentachloride on a dialkylacetoacetate would give rise to the formation of the chloride of a dialkylchlorcrotonic acid ; this, however, is not the case, the chief result of the reaction being a mono-, and a di-chloro-substitution product, together with a small quantity of a nionalkylchlorcrotonic ethylic salt, as the following experimental results testify.100 grams (1 mol.) of ethylic diethylacetoacetate boiling a t 205- 215" was poured into a flask containing 225 grams of phosphorus pentachloride (2 mols.). No reaction took place a t the ordinary tem- perature or at' 100" ; the mixture was therefore gently heated in con- nection with a reflux condenser until all the chloride had dissolved, and was kept boiling gently for some time.The upper end of the con- denser contained a calcium chloride tube, which entered a cylinder filled half .full of water. A thermometer placed in the vapour of the boiling liquid remained very constant a t 85", so the temperature in theliquid could hardly have been much over 100". During the reaction, volumes of hydrogen chloride were evolved, and also some ethyl chloride which could be inflamed in the cylinder. After boiling for five hours, the liquid had become pale yellow, and on cooling about 25 gra.ms of unussd phosphorus pentachloride crystallised out. The liquid poured off from the crystals was now distilled until the thermometer showed 120", in order to remove most of the phosphorus oxychloride and trichloride, of which it mainly consisted.The residue, which was now brown in colour, was allowed to cool and poured into cold water; and then, as it could not be boiled under ordinary pressure without undergoing considerable decomposition, it was distilied in a current of steam. The oil which passed over very slowly was heavier than water, and insoluble in it. It was collected in three principal fractions of equal volume (I, 11, 111). The first drops which distilled possessed a peculiar odour, resembling that of the camphor compounds ; this was collected separately, but owing to the small quantity it has not been more closely examined; i t boils below ZOO", with slight decomposition. The last portion was also collected apart (about 3 c.c., Fraction IT). Each of the above fractions was separated from the water, dried over sulphuric acid, and afterwards analysed.The aqueous distillate had a strongly acid reaction, but after neutralising with sodium carbonate, evaporating to dryness and exhausting with absolute alcohol, only a small quantity was dissolved, the residue consisting of sodium chloride. Tlie liquid in the fla3L- E 252 JAMES : ACTION OF PHOSPHORUS PENTACHLORIDE also had a strongly acid reaction due to phosphoric and phosphorous acids. Ir'ractim 1.-A portion ( a ) )of this slightly yellowish liqnid, on dis- t illation, boiled from 210" to 220" with decomposition, hydrogen chlo- ride being given off whilst a dark-brown resicluc remained in the rc tort. This distillate was analysed, as was also another portion which had not been distilled ( b ) .( a ) . 0.2685 gram substance produced 0.530 gram CO, and 0 2023 gram H,O. 0.2195 gram heated with CaO gave 0.118 gram AgCI. 0.3145 gram Tinally produced 0.195 gram AgC1. ( b ) . 0.255 gram substance gave 0.517 gram C 0 2 and 0 187 gram H20. Calculated foil Found. CH,Cl*CO * C (C,HJ ,*CO OCZH,. r ------7 L____-,--J a. b. G o . . ...... 120 54.42 35.86 55.3 HIT.. ...... 17 7-72 8.3 8.14 0 2 . . . . . . . . 48 21.77 - - c1 ........ 35.5 16.09 13.3 15 32 -- 220.5 100.00 The substance, according to these analyses, consist,ed mainly of ethylic diethylmonocbloracetoacetate slightly contaminated with a compound richer in carbon and hydrogen, probably free from clilorine. EthyZic dieth~ZchZorscetoacetate is a colourless liquid, insoluble in water, and of a pleasant odour.It is miscible in all proportions with alcohol, ether, aud benzene. Fraction 11.-This might consist of a mixture of the two substances which composed fractions I and IIJ, that is, a mixture of mono- and di-chlorinated ethylic diethylacetoacetate, but also of ethylic ethyl- chlorcrotonate, CH,-CC1 : C (C,H,)*COOC,H,. Two chlorine estimations, in two samples separately prepared, gave 21.8 and 21.1 per cent. C1, which agree pretty well with the amount of chlorine in this last-named ether, but also equally consistently for a mixture of equal numbers of molecules of mono- and di-chlorinated ethylic diethylacetoacetate. This fraction was consequently again distilled in a current of steam until one-half had passed over, dried over sulphuric acid, and the chlorine determined.Fraction, IIa. It has a sp. gr. of 1.063 a t 15". 0.288 gram substance produced 0.200 gram AgCl = 17.1 per cent. Cl.ON ETHYLIC DIETHYLACETOACETATE. 53 Fractioia IIb. 0.277 gram substance produced 0.265 gram AgCl = 23.6 per Calculated for ethylic diethylmonochloracetoacetate 16.1 per cent. Calculated for et'hylic diethyldichloracetoacetate 27.8 per cent. Presuming that fractional distillation in a current of steam can be carried out with a fair amount of exactitude,* these results tend to show that a compound was present which was neither the monochloro- nor dichloro-substitution product, since in the first case the chlorine cent. C1. found would be too high, stantiated this supposition half, and analysing it. 0.3245 gram substance cent.C1. and in the second too low. I have sub- by again distilling Fraction IIb to one- Fraction I I b 1. produced 0.266 gram AgCl = 20.2 per 0.3140 gram substance produced 0.6200 gram CO, and 0.2005 gram HZO. Calculated for Found. CBgCC1: C(C2H,j-COOC,H5~ r - ~ - - 7 L---r--J I. 11. Ce .......... 96 b4.4 - 53-85 H13. ......... 13 i.36 - 7.09 0, .......... 32 C l . . ........ 35.5 20.11 20.2 - - - - - 176.5 Although the percentage of chlorine found agrees with the above formula, still the carbon, and especially the hydrogen: are too low. It is, I think, extremely probable that this substance consists mainly of pure ethylic ethylchlorcrotonate, as the evolution of ethyl chloride and the occurrence of phosphorus oxychloride can then be satisf'ac- torily accounted for.Fraction 111.-Analyses hare shown this fraction to be a dichloro- substitution product of ethylic diethylacetoacetate. I. 0.274 gram substance produced 0.297 gram AgCl. 11. 0.3135 ,, Y 7 ,, 0.5455 gram COz and 0.182 gram H,O. The oil was now distilled to one-half, and that remaining in the The percentage was found to flask dried and analysed for chlorine. be nearly the same. * I n these operations a long-necked flask was used, and the tube in connection with the condenser was about in. in diameter.54 JAMES : ACTION OF PHOSPHORUS PENTACHLORIDE 111. 0.2715 gram substance gave 0.319 gram AgCl. Calculated for Found. CHCl,.CO .c! (CQHj) ,*COOC,II,. .r--h-- 7 L---- -"------J I. 11. 111. Cl0 ...... 120 47-05 - 47-4 - 6.4 - H 1 6 . . . . . . 16 6.27 - O3 .. . . . . . 48 C1, ...... 71 27.84 26.8 - 28.4 255 - - - - E t h y l i c ~~ethyldichloracetoacefate is an oily, slightly yellow liquid, having a pleasmt odour. Tt is' insoluble in water, but miscible with alcohol and ether, and has at 15" a sp. gr. of 1.155. I t cannot be dis- tilled under the ordinary pressure. Fraction 1V.-This liquid, consisting of the last drops which were distilled, appears to contain about 50 per cent. of a trichloro-substi- tution product of othylic die thylacetoacetate, the percentage of chlorine in which is 36.8. 0.2115 gram produced 0.2655 gram AgCl = 31.06 per cent. C1. 11. Formation of Qxyketones-Action of Sodium Methylate o n EtliyKc Diethylchloracetoacetate. A solution of 4.2 grams of sodium (I mol.) in 40 grams of methyl alcohol was poured into 40 grams ,of ethy lic diethylmonochloraceto- acetate* contained in a flask; a reaction took place at once with considerable elevation of temperatlure, the liquid becoming brown.It was necessary to place the flask in oold water for a time, but after- wards the mixture was heated on the water-bath, and finally in sealed tubes for three hours at 100". The contents of the tubes were then distilled to dryness on an oil-bath, and the distillate fractionated. Most of the methyl alcohol was thus separated, and the residue, which boiled from about 80" upwards, was shaken with a saturated solution of calcium ohloride several times, and the upper layer separated and submitted to fractional distillation. From this liquid, I succeeded in obtaining two compounds ; one boiled at 1SO-132" and represented the principal part, the other passed over between 18t5-190" and was obtained only in small quantity.An analysis of the liquid boiling at 185-190", which still contained a little chlorine, gave the following numbers :- * Obtained from 100 gramo of diethylacetoacetate and PCI,. After dietilling 1 or 2 C.C. in a current of steam, tLe remainder was collected until about two-fifths of tile whole had passed over.ON ETHYLIC DIETHYLACETOACETATE. 53 0.2265 gram substance produced 0.5135 gram CO, and 0.1855 gram H20. Calculated for ---7 Found. c11H!2004- Cl,.. ...... 132 61-11 61.82 H2o ...... 20 9.21 9.09 0 4 . . - ...... 64 29.68 216 100.00 -- - This result agrees in the main with the composition of ethylic methoxydiethy lacetoacetate, CH2( 0 CH3) C0.C ( CzH5),*COOCzHi,.It is a pleasant smelling, colourless liquid, soluble in alcohol and ether, and heavier than water, in which it is insoluble. I have not been able t o obtain this compound free from chlorine. If an excess of sodium methylate is taken, in order to remove the whole of the chlorine, the substance boiling from 13@-13;1" is chiefly produced. Analjsis of the body boiling from 130 -132" :- I. 0.276 gram substance gave 0.6475 gram CO, and 0.268 gram 11. 0.2745 gram substance, obtabed from a second preparation, gave 0.6465 gram CO, and 0.2725 gram H,O. 111. 0.2465 gram of the same substance gave 0.5820 gram CO1 and 0.2415 gram H20. IV. 0 320 gram of the portion boiling from 125-130", which was very,little, gave 0:7600 gram COz and 0.317 gram H,O.C;HI,O,. r 7 r-~-----! 1. 11. 111. IV. C, ..... 84 64% $64.0 64.2 644 64.7 H,, .... 14 10.8 10.78 11-03 10.84 11.0 O2 ..... 32 24.6 130 100.0 HZO. Calculated for Found. L - - - - -- - These numbers agree pretty well with each other, and with the formula of an oxyketone, viz., methoxymethy I-ethyl-acetone (methoay- methyl bzctyZ ketone), CH2(OCH3)*CO*CH(CH3) (CzH5). It might certainly have been expected that a methoxx-diethy Z-acetone would hare been formed, according to the following equations :-56 JAMES : ACTION OF PHOSPHORUS PENTACHLORIDE CH,CbCO*CEt,*COOEt + CH,*ONa = CH2(OCH3)*CO*CEt,*COOEt + H,O = CH,(OCH:,).CO*CEt,*COOEt + NaCl. CH,(OCH,)*CO*CHEt, + CO, + EtOH. But this, according to the analytical results, does not appear to be the case.The place of one ethyl-group has been taken by methyl, and this displacemeiit is probably brought about by the excess of methyl alcohol. The researches of Geuther and Bachmann (Annulen, 218, 49) have already shown that in the case of the ketals (and this oxy- ketone is possibly nearly related t o them) a positive organic radicle can be displaced by another poorer in carbon, e.g., by the action of methyl alcohol on diethylacetsl, methylethylacetal and dimethyl- acetal are formed. MethoxyrnethyZ-ethy Z-ncetone is a mobile, colourless liquid, of sp. gr, 0.855 at ZOO, very miich resembling acetal. It has a burning taste and a very pleasant odour, and it can be mixed with aIcohol and ether, but is insolubIe in water. It boils at 130-132", and the vapour burns with a luminous flame tinged with blue, No compound with sodium hydrogen sulphite could be obtained. Action of Sodium Methylate on Ethylic Diethyldichloracetoacetate.A solution of 9.5 p r n s of sodium (2 mols.) in 70 grams of methyl alcohol was poured into a flask containing 50 grams of pure ethylic diethyldichloracetoacetate, and the mixture treated precisely as before described. In this case also, I finally obtained two liquids boiling at 134--135" and 190-200"; this last portion was very little, and consisted chiefly of ethylic dimethoxydiethylacetoacetate, as the fol- lowing analysis shows :- 0,211 gram substance gave 0.4445 gram C02 and 0.165 gram H,O. C12H2205. CI2 ........ 144 58.53 57.4 H22.. ...... 22 8.94 8.7 O6 ........ 80 32.53 - Calculated for r--'h-- 7 Found.-- -- 246 100.00 I have endeavoured, in vain, to obtain this substance in a purer state; it always contains a little chlorine, and since it is slightly decomposed by distillation, the chlorine compound cannot be got rid of in this way. An excess of sodium niethylate causes a further decomposition, as in the case of the monochlori nated derivative.OX ETHYLIC DIET HTLACETOACETATE. 57 Ethylic dimsthoxydiethy laoetoacetnte, C H ( 0 CH,) ,*C 0 CE t 2*C 0 0 E t, is a pleasant smelling, colourless liquid, heavier than water, in which it is insoluble ; it boils with partial decomposition about, 195". An analysis of the substance boiling a t 134-1.35" gave the fol- lowing result :- I. 0.3235 gram substance gave 0.7335 gram CO, and 0.3065 gram 11.0.239 gram substance gave 0.5455 gram CO, and 0.225 gram H,O. HZO. Calculated €or Pound. c9 tl1303: r--J'-- 7 r--A- 7 T. IT. C9.. ...... 108 62.06 61.83 62.24 H18.. ..... 18 10.34 10-52 10.46 05.. -- - ...... 48 27..60 174 100.00 -- - These numbers correspond very closely with the abore formula, which represents a d.lnze~~oxy-di~thyl-~cetone, CH(OCH,),*CO*CH(CzH,),. The following equations explain its formation :- CHCl,*CO*CEt,*COOEt + 2CH,*ONa = CH(OCH,),*CO*CEt,.COOEt + H20 = CH(0 CH3),2* C 0. CE t,* C 0 0 E t . CH(OCH,),*CO*CHEt, + CO, + EtOH. It, is a colourless, mobile, pleasant smelling liquid, having a burning iaste. It is inso- luble in water, but miscible with alcohol and ether in all proportions. Its vapour burns with R luminous flame. No compounds are formed with acetic anhydride or sodium hydrogen sulphite.It boils a t 134", and has a sp. gr. of 0.856 at 15". The yield of these two methoxyketones is by no means a good one ; this is chiefly because a considerable quantity passes over with the methyl alcohol, and cannot be separated by fractional distillation ; still, by adding powdered calcium chloride to the methyl alcohol dis- tillate until a syrup is formed, shaking with ether-which dissolves the oxyketones-and then removing the ether on a water-bath a t 50", I have succeeded in recovering a fair amount of these compounds. I am not aware that a methoxyketone has been previously de- scribed, altliough L. Henry has recently (Bey.,, 14, 2272) prepared the58 O'SULLIVAN ON TEE SUGARS OF SOME CEREALS ethyl salt of the alcohol of pyroracemic acid, CH3*CO*CH,*OC,II,, which he obtained from propargyl ether by means of mercuric bromide and water. .Ammonia alzd Etiiylic Diethy lacetoacetnte. By the action of concentrated aqueous ammonia on this substance, it was expected that amides would be obtained analogous to those produced from ethylic acetoacetate, at the same time its abnormal reaction with phosphorus pentschloride seemed to predict failure, and this prediction has been verified by experiment. No reaction takes place at 120-130" in sealed tubes, and on heating still higher, finally to 190-200", the etliylic diethylacetoacetate becomes decomposed, forming ammonium carbonate and diethylacetone boiling a t 135-137".

ISSN:0368-1645    

DOI:10.1039/CT8864900050

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

58 O’SULLIVAN ON THE SUGARS O F SOME CEREALS VITT.-On the Sugal:s of Xome Cermls and of Germinated Grain. ‘By C. O’SULDIVAN, F.R.S. IN the analyses of the cereals, and of germinated grain hitherto published, if sugar is mentioned as one of the constituents, the particular sugar OT sugars have not been specified. Kuhneman, Rer., 8, 202, indeed, stat,es that he isolated 0.6 to 1 per cent. sucrose (cane-sugar) from germinated barley ; the evidence for the statement, as published, is, however, unsatisfactory and unconvincing. As the question of the presence or absence of a sugar or sugars, and a determination of the particular variety thereof, is of considerable practical importance, I may be permitted to record the results of an investigation undertaken with this object in view.I shall describe the experiments with barley, as the operations employed in dealing with it answer also for the other cereals, raw rand germinated. The ground grain, when treated with water, yields the sugars to that solvent, but, a t the same time, other compounds are dissolved, which render it imposqibio to bring the .solution into such a condition as would admit of its being satisfactorily worked with. The amount of material which it is necessary to take requires the employment of much solvent, so that the washings are rery dilute, and the solution cannot be concentrated, unless, indeed, under diminished pressure, without the development of much colour, and the formation of decompoiition product,.. I have, on another occasion, pointed out thatAND OF GERMINATED GRAIN.59 alcohol, sp. gr. 0.90, yields a clean, fairly workable solution, but the amount of mucidin and fibrin dissolved is so great that it is almost impossible to concentrate the extract obtained with it by distillation, because, when the greater part of the alcohol has passed over, the liquid in the distilling flask froths up and is carried over in quantity. Strong spirit, in which the albuminoids are insoluble, cannot be used with advantage, as the sugars are not very soluble in it. I n consequence of these considerations, I found it necessary to proceed as follows. 200 grams finely ground barley (this was a convenient quantity to work with), were introduced into a flask 'capable of holding 1-5 litres ; 200 C.C. of alcohol (sp. gr. 0.9) added, and the.mixture allowed to stand for 2 4 hours. 400 C.C. alcohol, sp. gr. 0.84, were then added, and the whole digested a t 40° for four hours. The solution was filtered while still warm, and the filtrate kept by itself to cool; the residue being washed by decantation several times with alcohol, sp. gr. 0.85--0.86. It is well to keep the first 200 or 300 C.C. of washings by themselves, because they, as well as the first filtrate, deposit a considerable quantity of albumino'id on cooling. When the extract and the first portion of the washings had become clear, after cooling, they were mixed with the final washings and submitted to di,ctillation, 300 or 400 C.C. at a time. Each portion was concentrated to about 50 c.c., and the residues were collected and allowed to cool.Much albumino'id separated, and after 24 hours the supernatant liquid was bright. This was again decanted into a distilling flask, the insoluble deposit washed with a little water, the washings added to the contents of the flask, and the whole submitted to distillation until the residue was less than 100 C.C. and free from alcohol. This was shaken with a little aluminium hydroxide and filtered ; the filtrate with the washings was made up to 160 C.C. As the extraction and the washing had been carefully done, this 100 C.C. contained all the ready formed sugars of the 200 grams barley: the solution was sufficiently bright for optical observations. The sp. gr.* of the solution was found to be 1.02445; it had an optical activity = 10.1 divisions,t in a 200 mm.tube of a Soleil-Scheibler saccharimeter, and 12.159 grams of it reduced 0.1943 gram CuO. 80 C.C. of the solution * I n speaking of specific gravity it will be understood that I mean the weight of the solution compared with the weight of water, the bulks and temperatures being equal, and the weight expressed in the ratio of water = 1. I make the comparison at 15.5", and this may be indicated sp. gr. = 1. 15.0 -t In this paper, I employ the divisions of a Soleil-Scheibler instrument to express the optical activity, because they answer the purpose as well as angular values, and the trouble of calculation is thereby avoided. The observations are all 1i:tlde in a 200 m ~ u . tube aud at a temperature of 15.5".60 O'SULLIVAN ON THE SUGARS OF SOME CEREALS were digested in a flask with 0.03 gram invertase for 4 hours at 52-54' ;* after cooling, the contents of the flask were made up to the original bulk (80 c.c.) by the addition of a few drops of water, and filtered.The solution was then sufficiently bright for an optical observation. Occasionally, however, the filtrate, obtained in the way indicated, fi-om some material, requires tot be treated with a little animal charcoal ; in such cases, the least possible quantity should be used. The sp. gr. of the filtered solution was found to have increased to 1.02525, the optical activity to have diminished to - 2.51 divs., and the K to have increased-3.146 grams solution reduced 0243 gram CuO.. From these data, the K of the original solution was = 0.74 gram dextrose, which was increased to 3-58] grams by the action of invertase ; the loss in optical activity on inversion was represented by 12.61 divs.(10.1 + 2-51> ; and the increase of solid matter, as indicated by the sp. gr., was =3 0.21 gram.+ The original solution, therefore, con- tained a substance capable of being acted upon by invertase, yielding thereby a substance of increased reducing power, of diminished optical activity, and of increased sp. gr. These are some of the properties of sucrose; in fact, there is no other known sugar acted upon by invertase in the way described. Let us see how the factors observed agree with those belonging to that sugar-how the increase in reducing power agrees with the diminution in optical activity. The 2-84 grams (358 - 0.74) of reduction would be yielded by thc inversion of 2.69 grams sucrose, because 105.25 : 100 : : 2.84 : 2.69, the first term being the amoant of invert sugar yielded by 100 grams of cane-sugar.Now 1 gram sucrose in 100 C.C. solution, when acted upon by invertase, loses an optical activity = 5.18 divs., the observed loss was 12-61 divs.; hence, 12-61 + 5.18 = 2-43, the grams of sucrose in the 100 C.C. solution. the optical activity indicates 2.43 grams sucrose, and the reduction ,, 2.69 ,, sucrose. Further, 2-68 grams sucrose, on being inverted, take up 0.15 gram water; the observed increase in sp. gr. indicates 0.21 gram, including the invertase. In this experiment the agreement between the sucrose, calculated from the optical activity and the reduction, is not as close as usual ; in another experiment the optical activity yielded! 2.79 grams sucrose, and the reduction ,, 2.77 ,, sucrose; * If sulphuric acid were employed, it would act not only upon the sucrose, but t Part of th:s is, no doubt, due to concentration during filtration.We thus see that- also upon maltose and dextrose, should they be present.ASD OF GERMINATED GRAIN. GI and the results of very many determinations lie bet8ween these two cxtremes. Hence the evidence for the presence of sucrose is as con- clusive as need be desired. Having obtained this evidence, we may turn to an examination of the reducing power in the original 100 C.C. solution, and see if we can determine to what sugar or sugars it was due. It may have been due to inverted sucrose ; if so, the optical activity of the amount of reduction, taken as invert sugar, plus the optical activity of the sucrose found, should be equal to the optical activity observed.The original reduction corresponds t o 0.74 gram invert sugar, and we may take the sucrose a t 2.69 grams; now 1 gram sucrose in 100 C.C. solution is equal to 3.84 divs., and 1 gram invert sugar to - 1.23 divs. ; hence 2.69 x 3.84 = 10.33 less 0.74 x 1.23 = 0.91 = 9.42, the number of divisions corresponding to such a mixture ; the activity observed was 10.1 divs. These numbers do not agree sufficiently closely t o give any support to the supposition, and, even if the approximation were closer, the evidence for the inference would be far from con- clusive. Of course, if the quantity of sucrose indicated by the optical activity were taken for the purpose of the calculation, the difference between the observed and calculated numbers would be greater. A mixture of lamdose and dextrose could be worked out to fit in witli the ohserred optical activity, but this would be in no way satis- factory ; I, therefore, tried by other means t o obtain evidence of the character of the sugar. 66.939 grams of the inverted solution were sterilised by boiling and cooled ; 0.4 gram pressed yeast was added to them, and fermentation allowed to take place, first a t the ordinary temperatu-re, and then a t 20-2.2".The apparatas in which this operation was conducted con- sisted of a flask capable of holding 120 c.c., in which was the fer- menting liquid, and two small wash-bottles, through a few C.C.of water in each of which t?le carbon dioxide evolved was made to pass. At the end of 10 days, when all action had ceased, the fermented liquid was transferred to a distilling flask, the first rinsings being made with the water of the wash-bottles, and further with a few C.C. water, care being taken that the liquid and washings did not much exceed 100 C.C. The distillate was collected in a 100 C.C. vessel, as is done in the usual method of determining original gravities. When nearly 100 C.C. had passed over the operation was stopped, and the distillate made up a t 15.5" to 100 C.C. Of this the sp. gr. was found to be 0-99i72, which, according to Fownes' tables, is equal to 1-22 grams absolute alcohol in the 100 C.C. Now as only 66.93 grams original solution, sp.gr. 1.02525, were taken, we arrive a t the quantity of alcohol derivable from the whole 100 C.C. by the proportion- 66.94 : 102.53 : : 1.22 grams : 1.87 grams ;62 O'SULLIVAN ON THE SUGARS O F SOME CEREALS that is, the original 100 C.C. solution would have yielded 1-87 grams absolute alcohol. According to the best available determinations (Pasteur, Awn. Chim. Phys., 58, 323), 100 grams of a C,H,,O, sugar yield 48.5 grams alcohol ; the 1.87 gram is, therefore, the product of 3.86 grams sugar, for- 49.5 : 100 : : 1.87 : 3.86. The reducing power in the inverted solution was only = 3.58 grams of dextrose; hence, we have here an indication that a sugar with a less reducing power than invert sugar, or one with no reducing power a t d1, had fermented.Let us now compare these numliers with the amount of solid matter that disappeared from the solution during fermentation. The contents of the distilling flask were transferred to a 100 C.C. measure, and with the washings, were made up to the 100 C.C. mark at 15.5". The sp. gr. was found to be, with the yeast in, 1.00676, and, after the yeast was separated by filtration, 1.00620. The 0.4 gram yeast originally added contained 0.13 gram solid matter, whereas the presence of the yeast in the fermented liquid was indicated by a sp. gr. of 1*000.56 = about 0.14 gram ; consequently, the yeast may be considered to have done its work without having taken anything from, or yielding anything to the solution. Had the whole 100 C.C. been taken, the sp. gr. of the residue would have been 1.00948, because- 66.94 : 10253 : : 620 : 948; hence, 1.02525 - 0.00'348 = 1.01577, the sp.gr. in 100 C.C. of the matter fermented.. If we t'ake 1.00385 as representing the gravity of 1 gram sugar in 100 C.C. solution, the sp. gr. of the matter fermented indicates 4-09 grams, and this without, taking into account t,he glycerin,. succinic acid, &c., produced. We have then the following numbers for the sugars in the inverted solution :- 3.58 grams from reduction, 3-87 ,, ,, the alcohol on fermcntation, and 4.09 ,, ,, the gravity lost on fermentation. The numbers calculated from the alcohol and from the gravity lost on ferment,ation should agree better than they do in this case, aiid I may say, they usually do, but these results afford a clear indication of the facts generally observed.Without giving preference to any one number, we may, for our purpose, take that derived from the alcohol as the amount of sugar that had fermented. When we compare this XTith the amount of sugar representled by the reducing power, we observe that at least 0.29 gram (3.87 - 3.58) of matter which had noAND OF GERMINATED GRAIN. 63 reducing power fermented. This is a property of maltose, hut the body may be any non-reducing sugar not acted upon by invertase. Before we enter, however, into a consideration of this part of the subject, I must mention that the unfermented residue had no optical activity, and that 25 C.C. of it, boiled with 10 C.C. Fehling's solution properly diluted, gave no trace of reduction even after 15 minutes' boiling; a slight precipitate did form, it is true, but this was flocculent and white ; hence, all the sugars had fermented.This result is not always obtainable ; the residue very frequently exhibits an optical activity, and possesses a reducing power. Sometimes, the relaticjn of the reducing power to the optical activity is such as to indicate the presence of maltose, but, as a rule, the relation holds good for no known sugar, and the optical activity is high for the reduction, higher than would be indicated by dextrose, but no definite factors can be arrived at' the quantities are too small. The residual optical activity being a + quantity, the sugar cannot be laevulose, and i t must be less fermentable than that sugar, or i t would not have been left behind whilst the invert sugar disappeared. Now, to return to the matter fermented: it seems a t first sight, as if the 0.29 gram of non-reducing powel-, described above as disap- pearing during fermentation, might be due t o the presence and fermentation o€ 0.77 gram maltose (37.5, the non-reducing power of maltose : 0.29 : : 100 : 0*77), but when we consider that the optical activity due t o the sucrose is + 10.33 divs., whilst the original activity was only = 10.1, we see that the sugars other than sucrose must have a minus power = - 0.23, and, therefore, this could not under any circumstances be due to maltose alone, and probably not to any mixture of maltose with other sugars.If it were not for the disap- pearance of this non-reducing matter during fermentation, it would appear probable that the original reduciug power, judging from the optical ac#ivity, is due to dextrose and laevulose, the former being in excess.I may s t a h that when barley has been extracted with alcohol as described, if the residue is treated with water, the aqueous solution concentrated, and the amylans and other substances precipitated by alcohol, sp. gr. 0.84, the alcoholic supernatant liquid contains no optically active or reduaing substance. This I proved by distilling off the alcohol, and concentrating the residue to a small bulk. All the sugars of barley can, therefore, be dissolved by careful treatment with alcohol as described above. Such are the general indications regarding the sugars in barley. The results of the examination of at least 20 varieties may be sum- marised as follows :- 1st.The diminution in optical activity and the increase in reducing64 O'EULLIVBN ON THE SUGARS O F SOME CEREALS power, produced by the action of invertase, agree well with the factors of sucrose, and the numbers obtained show that barley contains between 0.8 and 1.6 per cent. of that body. 2nd. There is a variable quantity of a sugar or sugars present which reduce less than d.extrose, and the optical activitr of which is always a minus quantity, but I have not been able to establish any satisfactory constant relation between the optical activity and K. 3rd. Frequently the solution containing the sugars does not completely ferment ; when this is the case the residue has a positive optical activity and a K which are variable, and cannot be referred to any known sugar.Wheat, treated in the same way, yields not more than 0.5 per cent. sucrose, but there are indications of a moderately high laevorotary, non-reducing, fermentable sugar of which I hope to be able to say something at a future time. I n dealing with germinaked barley (malt), I found 100 grams sufficient for the purpose, but as it is well to have at least 125 C.C. of solntion, I employ 125 grams substance. 125 grams malt, finely ground, were digested at 40' with 500 C.C. alcohol sp. gr. 0.9 for six hours ; to this 700 C.C. of alcohol, sp. gr. 0.84, were added, and the mixture allowed to stand for 24 hours. The clear supernatant liquid was decanted through a filter, and the residue washed gradually with 400 to 500 C.C.of alcohol of the last- named strength. The filtTate was then treated in the same way as is described in the case of barley, and 125 C.C. of fairly colourless, bright, aqueous solution obtained. The sp. gr. of this solution was 1.4890, and its optical activity = 355 dim. In determining the reduction- The substance is less fermentable than laevnlose. 1st Exp. 2.793 grams solution gave 0 207 gram CuO. 2nd Exp. 2.920 ,, ? 7 ,, 0.217 ,, CUO. These numbers correspond to- 1st Exp. 3.52 grams dextrose in 100 C.C. solution, and 2nd Exp. 3.55 ,, 9, ,, solution. To 100 C.C. of the salution, 0.06 gram invertase was added, and the whole digested atl 5 0 5 3 " for fonr hours. This was sufficient to com- pletely invert any sucrose that may have been present. The solution was cooled to 15*5", and then made up witth a few drops of water to 100 C.C.The sp. gr. of this solution was 1.05020, and its optical activity = 11.2 dim. :- 1st E X ~ . 1.322 grams of it gave 0.239 gram CuO, and 2nd Exp. 1.124 ,, ,, 0.204 ,, CuO.AND OF GERMINATED GRAIN. 65 These numbers correspond to- 1st Exp. 8-61 grams dextrose in 100 C.C. solution, and 2nd Exp. 8.64 ,, 9 , ,, solution. The increase in reduction i p , therefore, equal to 5.11 (8.64 - 3-53 = 5.11) grams dextrose or invert sugar, corresponding to 4.85 grams The optical activity in the original solution was 35.5 divs. ; after inversion, i t was 11.2 diva. ; there was consequently a loss of 24.3 divs. ; a loss of 5-18 divs. corresponds to 1 gra,m sucrose in 100 c.c., and E3 = 4.69, the number of grams sucrose iadicated by the decrease 5-18 in optical activity. We have then, in the 100 C.C.solution, 4.85 grams sucrose indicated by the increase of reduction, and 4.69 grams sucrose indicated by the decrease in optical activity. These numbers, it will be observed, are percentages on the malt t,aken. I n order to obtain some knowledge of the character of the reducing bodies in the original solution, the inverted solution was submitted to fermentation. Before examining the results of this experiment, i t may be as well to consider with what compounds we are likely to have to deal. We may take it that the original solution contained 4.7 grams sucrose in 100 c.c.; the optical activity due to this is 18.05 divs. (4.7 x 3.84) ; hence, 35.5 - 18.05 = 17.45 divs., are due to the Eugars represented by the 3-53 grams of reduction.If the reduction be taken as dextrose, the optical activity is too high, if as maltose, too low; it mixture of maltose and dextrose could be calculated to agree with it, and one in which lawulose was also present could be made to fit in, but as we have no evidence of the presence of either sugar at present, we must turn to the fermentation experiment to throw some light on the subject,. 102.4 grams of the inverted solution were sterilised and submitted to fermentation with 0.5 gram pressed yeast, the usual precautions being taken to make the carbon dioxide evolved pass through two wash-bottles containing a little water. Towards the end, it was neces- sary to add 0.002 to 0.003 gram active diastase t o ensure the complete fermentation of the optically active and reducing bodies. The fermentation finished, the solution yielded on distillation- 100 C.C. alcohol, sp.gr. 0.99193, and 100 C.C. residue, sp. gr. 1.01473 with yeast in, and sp. gr. 1.01392 ,, out. VOL. XLXX. F66 O'SULLIVAN ON THE SUGARS OF SOME CEREALS The clear filtered residue was optically inactive and had no reducing power. The sp. gr. of the distillate indicates 4.50 grams alcohol in the 100 c.c., and if it be admitted that this is derived from a CsH,,Oc sugar, we get from the proportion 48.5 : 100 : : 4.5 : 9-28 the number of grams of sugar whence i t was derived. 102.4 grams of the original solution were employed, the proportion Now as only 102.4 : 105.02 : : 9.28 : 9.51 gives the grams fermentable in that solution.On the other hand the total reduction was equal only to 8.64 grams dextrose ; hence, it would appear from this, that 0.87 gram of matter not indicated by reducing power fermented, but as we have no evidence that all the alcohol was derived from a C6H1206 sugar, the factor is not of so much value as is desirable. Let us see what can be made of the difference between the original sp. gr. of the solution and that of the residue. As pointed out above, the 102.4 grams solution gave 100 C.C. residue, sp. gr. 1.01473 with yeast in, and 1,01392 after the yeast was sepa- rated by filtration. The amount of yeast in the residue was repre- sented, therefore, by 100 c.c., sp. gr. 1.00081. 4.264 grams of the pressed yeast employed, suspended in 100 C.C.water, gave a sp. gr. = 1.00466; the 0.5 gram used would, therefore, give a sp. gr. = 1.00054, thus leaving a quantity of matter represented by 100 C.C. solution, sp. gr. 1*00027 (0.00081 - 0*00054) : this does not amount to more than 0.07 gram, and as we do not know at present whence it is derived, we may neglectj it. The unfermented residue that was left on the fermentation of the 102.4 grams inverted solution amounted to 100 C.C. of sp. gr. 1.0139%, which, calculated out in the same way as was the barley residue, gives the matrter disappearing during fermentation as 9.33 grams; but this figure can, as was before shown, only be taken as an approximation. The number calcn- lated from the alcohol is 9.51, but this may be too high, a C12H,,01, sugar may have yielded a portion of it, whereas that derivedfrom the gravity must be too low, as the glycerin, succinic acid, &c., were not allowed for.I f , therefore, the mean of the numbers be taken, we cannot be far from the truth ; in this way we arrive at 9.42 grams as the amount of matter fermented. The reduction before fernlentation represented 8-64! grams sugar, and as 9.42 grams fermented, 0.78 gram of matter without reducing power must have disappeared. If this be attributed to maltose, we have 2-08 grams of that compound, because 37.5 : 100 : : 0.78 : 2.08 ;AND OF GERMINATED GRAIS. 67 and 9-42 - 2.08 = 7-34 grams other sugars. 4.7 grams sucrose yield 4-94 grams invert sugar (reduction), and 2.08 grams maltose give 1.30 grams reduction ; consequently, the original solution coiitained 2-40 grams of other reducing sugars- 8.64 - (4.94 + 1.30) = 2.40.Admitting the quantity of sucrose and maltose to be correct, let us see what optical activity will belong to these sugars. Sucrose ........ 4.7 x 3.84 = 18.05 divs. Naltose ........ 2.08 x 8.02 = 16.68 ,, -- Total ...... 34.73 ,, The observed activity was 35.5 divs., thus leaving a dextro-power = 0.77 divs. for the 2.4 grams sugar. These may be leoulose and dextrose, the latter being in excess. The quantity of each, in 100 c.c., may be calculated thus:- - 5*52 2’4 -t 0*77 = 1-65 gram dextrose, 2-56 + 5.52 and 2.4 - 1.65 = 0.75 gram lzevulose; - 5.52 and 2.96 being the number of divisions due to 1 gram lzevulose and 1 gram dextrose respectively in 100 C.C.solution; 2.4 the total sugar in grams, and 0.77 the optical activity in divisions due to them. From these data, the malt employed contained- Sucrose. . . . . . . . . . . . 4.70 per cent. Ma1 t ose. . . . . . . . . . . . 2.08 , , Dextrose . . . . . . . . . . 1-65 ,, Lzevulose .......... 0. i 5 , , Total sugars. ..... 9.18 ,, 0.24 for the hydration of sucrose, and we get ...... 9-42 the amount of matter that disappeared during fermentation. Results similar to these have been obtained for all the malts worked with. I have tried to give, as clearly as possible, the evidence for the presence of each sugar; that for the sucrose leaves little to be desired, it is satisfactory ; with regard to the maltose the evidence is not so convincing, for, although a certain quantity of matter without reducing power disappears during fermentation, and the solution has a sufficient optical activity to admit of the presence of the amount of maltose calculated therefrom, as we have no means of checking one result by the other, we cannot say that tjhe observed facts are due -- Add ..............68 O’SULLIVAN ON THE SUGARS OF SOME CEREALS absolutely to maltose ; of that for the laevulose and dextrose all that can be said is, that there is a reducing power with which certain mixtures of them correspond, and, that when the cane-sugar is low in a malt, its place is taken by a reducing power and optical aotivity which san be referred to laevulose and dextrose.I shall, however, show that it. is not difficult to strengthen the evidence for the presence of maltose.In nearly all cases, in the fermentation experiments, unless a little a d v e diastase had been added to the solution, it was, after the fermentation had ceased, optically active and reduced copper solution, the optical activity being, as a rule, but not always, equal to that of maltose calculated from the reduction. This is usually the case when the fermented solution gives a reduction* equal to from 0.6 to 0.8 gram dextrose, correspond- i n g to 0.9 to 1.1 of maltose in 100 C.C. Sometimes, indeed, the optical activity is greater than the maltose calculated from the reduc- tion ; this may be attributed to a little dextrin or malto-dextrin, and it very probably is due to one or both, but I have no farther evidence to prove it. I met with the indication only in a few malts.Before summing up the results, I should state that it is very diffi- cult to free malts from sugars by treatment with alcohol; indeed. although I have made at least 20 estimations, I have only succeeded in a few cases in obtaining a residue perfectly free from sugar. To determine the point, the residue was treated with water at 40°, the extract evaporated to a small bulk, which is, in this case, easily accomplished without the development of much colour, and 40 to 50 C.C. hot alcohol (0.85) added ; this throws down mnch flocculent matter, and the clear supernatant liquid contains the sugar. This is usually maltose, as invertase produces no change, and the reducing power and optical activity corresponds to maltose. In this way, I have found as much as 0.7 gram sugar left behind on treating 100 grams malt. This may be due to the action of water and a little diastase on the broken starch granules, but I think it is hardly so, as very little, if any, of the transforming agent can be present.The chief results obtained from the analyses of over 20 samples of malt, from various sources, by the method described, may be sum- marised as follows :-- * The est,imation of the reduction in the fermented solution leaves much to be desired, in consequence of the precipitation of other matter with the copper sub- oxide. When sufficient reduction is given by 12 to 15 C.C. of the solution, and these are heated to boiling, and added to the boiling dilute copper solution gradually, the precipitate represents the reduction fairly accurately, but when the reducing power is low, and 25 to 30 C.C.of the fermented solution have to be ttlkea, the pre- cipitate is decidedly impure ; it blackens on drying, and, on ignition, burns like tinder.AND OF GERMINATED GRAIN. Before gcrinination. 69 After germination. 1st. Malts contain from- 2.8 to 6.0 per cent. sucrose, 1.3 to 5.0 ,, maltose, 1.5 to 3.0 ,, dextrose, and 0.7 t o 1.5 ,, laevulose. This does not mean that any variety contains only the maximum or the minimum of all the sugars, but that the numbers given were those observed in individual cases. 2nd. As a general rule, the sncrose and maltose are high in highly germinated grain, and, when the sucrose is low in such grain, its place is taken by the products of its inversion, laevulose and dextrose.3rd. The numbers given as the results of the above described experiment may be taken as fairly typical. Without going into details, I ma'y say that germinated wheat yields similar results. That some idea may be conveyed of the changes that take place in the sugars duriiig germination, I give the results of the analyses of two barleys before and after germination, calculated per cent. on the dry matter of the barley, the yield of dry malt being known. Before germination. Sugars. After germination. I Sucrose . . . . . . . . Maltose . . . . . . . . Dextrose . . . . . . Lsvulose ...... 1 -38 J 4 - 5 1.98 1'57 { 0.71 -1----I----I 0.9 4-5 1 *2 0'2 No. 2 bn~ley. From this, i t is clear that during germination sucrose increases largely, and that there is a decided production of maltose, dextrose, and laevulose. The high dextrose in No. 1 germinated barley is frequently observed, but then, as in this case, the maltose is low, thcl fact pointing apparently to a conversion of that body. Starch disappears to a considerable extent during germination ; from it the maltose is most probably derived. The source of the sucrose, and of the products of its inversion, is not so easily indicatetl. I need hardly point out that sucrose can be easily detected in unfermented malt-wort by the loss of optical activity on addition of * Sugars other than sucrose, by fermentation experiment.70 O'SULLIVAN ON THE PRESENCE OF iiivertase. This inversion also takes place immediately on the addition of yeast, or in a short time if the wort be kept after exposure to the air, doubtless from the growth of fortuitous yeast. I n a wort sp. gr. 1.065, a diminution of as few as 5 and as many as 10 divs., corresponding respectively to 5.7 and 11.4 per cent. sucrose on the wort matter, have been observed on digestion at 50-52" with i nvertase. In conclusion, I may say that I have simply given the evidence from which my inferences are drawn ; this evidence must be taken for what it appears to be worth; for myself, I shall not be satisfied until each individual sugar is separated, crystallised, and examined by itself. Further, I have as briefly as possible indicated how the data were obtained ; if I were to give all the analytical numbers upon which the inferences are based, I should have to occupy much more space than the facts outside the inferences are worth. My thanks are due to my brother James, and t o nig friend Mr. F, W. Tompson, for much assistance in doing this work.

ISSN:0368-1645    

DOI:10.1039/CT8864900058

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

70 O’SULLIVAN ON THE PRESENCE OF I X - O I L t h e Presence o j ‘‘ Rafinose ” in B a d e y . By C. O’SULLIVAN, F.R.S. IN the preceding communication, I pointed out that, although the evidence for the presence of certain sugars in barley was moderately conclusive, we conld not be absolutely satisfied until each sugar was isolated and examined by itself. So convinced was I of the truth of this proposition that eight or ten years ago, early in my investigation on the sugars of the cereals, I made an attempt to crystallise them. With that object in view, 2 kilos. of ground barley were extracted with alcohol in the same way as is described for the 200 grams in the last. paper. The solution, freed from alcohol, was evaporated to a syrup, which was dissolved in the least possible quantity of boiling alcohol, sp.gr. 0.83. This solution, on cooling, deposited a syrup which was itgain dissolved in just sufficient alcohol to hold it in solution when cold ; a little ether was then added to produce a slight turbidity, and the whole put aside to crystallise. In a short time, cauliflower-like segregations began to form, and aft’er a few months they ceased to increase. These were collected, washed with strong alcohol, and put aside labelled “ Suci.ose (cane-sugar) from barley,” for no other reason than that they appeared under pretty much the same conditions as those under which Kuhneman (Ber., 8, 202) said he isolated cane-" RAFFINOSE " IN BARLEY. 71 sugar from malt. The quantity I obtained was not large ; it did not amount to more than 1.4 grams, or about 0.07 per cent.of the barley employed. Although t,his was amply sufficient t o determine whether i t was sucrose or not, so certain was I that it was, its crystal- line appearance notwithstanding, that I did not think it necessary to examine it. Working with the barley of the season 1878, I believe, in the same way, I obtained 4.55 grams of the cauliflower-like segregations from 5 kilos. material. This too I put aside, labelled '' Cane-sugar from barley." Recently, while arranging the material f o r the preceding paper, I thought it desirable t o examine more closely the two preparations described above. If they were sucrose, I had no doubt I could, by recrystallisation, obtain recognisable crystals of that substance. Before dissolving them, I examined a little of each preparation under the microscope ; I found the crystals were elongated, flattened prisms terminated by a dome parallel t o the shorter axis, the groups or segregations consisting of the crystals radiating from a centre. Both samples were alike, hence I had undoubtedly t o do with a sub- stance altogether different in crystalline form from sucrose.I pro- ceeded to examine the preparations farther. A determination of the optical activity of the dry matter in the one gave [ a ] j = 125", and in the other [ a ] j = 1 1 4 O . Both preparations were impure, for each contained a considerable quantity of ash, but it was evident that I had the same substance to deal with. I dissolved them together in a little water, filtered from some insoluble matter, and added strong alcohol until a precipitate began t o appear.This solution, on standing, was filled with radiating groups of beautiful silky crystals, which were collected, and washed with alcohol so regulated in strength as to produce no turbidity in the mother-liquid, the sugar being precipitated as a syrup on adding strong alcohol to the concentrated solution. The crystals are well-defined, flat, probably rhombic prisms, FIG. 1. EIb. 2. FIG. 3.72 O'SULLIVAN ON TBE PRESENCE OF terminated by a brachydome. Figs. 1, 2, and 3 give a fair idea of their shape. A second crop of crystals was obtained by concentrating the mother- liquor to a syrup, and again adding a little strong alcohol. On determining the optical activity of these, I found the results did not quite agree; the first crop gave [ a ] j = J 29.8" (c = 4*142), and the second [ a ] j = 132" ( c = 2.392) ; both still contained ash.As, however, the opt>ical activity was so near, and the quantity of sub- stance at my disposal so small, I mixed the two specimens, and sub- mitted the mixture to recrystallisation. A first and second crop of crystals were obtained as in the first instance. I now found that both preparations had practically the same optical activity, viz., for the substance dried in a vacuum over sulphuric acid and then in dry air at 100" until the weight was constant, [a]j = 134-135" (c = 4 to 5); hence, I concluded I had purified the substance. 1st Exp.-O.992 gram of the crystals, first allowed t o remain in dry air until the weight became constant, lost in a vacuum over sulphuric acid 0.142, and then, in dry air at loo", a farther 0.008 gram, making a total loss of 0.150 gram.2nd Exp.-2.061 grams, dried in the same way, lost a total of 0.312 gram. These results iudicate- 1st Exp. 15.12 per cent. water. 2nd Exp. 15.14 ,, 9 , Submitted to combustion in a stream of oxygen, 0.3148 gram dry substance gave- COz = 0.4893 gram, and H,O = 0.1825 ; 0.0020 gram ash was left in the boat; this was chiefly potassium carbonate. The numbers give- Carbon.. . . . . 42.66 per cent. Hydrogen.. . 6.47 ,, 6-35 ,, Theory for CgHl6O8. 42-85 per cent. These percentages are sufficient to indicate the empirical formula of the body in the dry state, and, from the amount of water lost by the crystals, we get the formula- or by doubling it to eliminate the $ mol.HzO, CJLO,, 23H20, which probably represents the molecular formula of the substance." RAFFINOSE " IN BARLEY. 73 An aqueous solution containing 1 gram dry substance in 100 C.C. had a sp. gr. 1.003965 ; this shows conclusively that the substance as burned did not contain any water of crystallisation. The dry sugar absorbs water from the atmosphere and becomes a glassy mass. 2.227 grams dry substance in 50 C.C. solution gave aw optical activity = 31.4 divisions of Soleil-Scheibler's instrument ; from this, the specific rotary power for the dry sugar is [ a ] j = + 135.3". It does not reduce copper solution ; 0.1 gram boiled for 25 minutes with 25 C.C. Fehling's solution, properly diluted, yielded only a trace of copper suboxide.Invertase appears t o act upon it, but very slowly : to 25 C.C. of a solution possessing an optical activity = 28.2 divs., 0.015 gram invertase was added, and the mixture digested at 50-52" for three hours ; the optical activity of the cooled solution was = 25.divs. A little more invertase was added, and the digestion continued for another three hours ; the activity had then fallen t o 21 divs. This was a slow process, but does not leave a doubt that invertase has an invertive action. Had sucrose; in the same quantity, been in the solution, it would have been all inverted in the first three hours. A one per cent. solution of sulphuric acid at 100" reduced the optical activity, in one hour, from 28 divs. to 10 divs. In this case, the products of inversion had 5t sp.rt. pr. The amount of material at my disposal did not warrant farther experiments in this direction, so I did not continue then. Treated with 4 parts nitrioacid andtl part water, it yielded a little less than 30 per cent. on dry substance of an insoluble acid, which, from its general behaviour and appearance under the microscope, is muck acid. The filtrate from this acid, neutralised with ammonia and acidified with acetic acid, yielded a precipitate of calcium oxalate on the addition of calcium chloride. From these facts, it is highly probable that galactose is one of the products of inversion, and, from the composition, that two other sugars are produced. These must be sacchsric and oxalic acid yielding sugars. = 43.5", and a K = 80.8. The sugar is fermented by ordinary yeast.I had worked with this sugar some time under the name of " cerenlose," but the recent papers of Scheibler (Rer., 18, 1779) and Tollen (Bey., 18, 2611) leave no doubt on my mind, that it is the " rafinose " of Loiseau (Compt. rend., 82, 1058). Whether the sugar is Berthelot's mellitose as Tollens says raffinose is, I am not prepared to say. Scheibler can say whether my description of the crystals agrees with his observations. My analytical numbers agree well with his, for, although he burned the crystals, and I the dry substance, the VOL. XLIX. G74 ARMSTRONG AND MILLER: THE DECOMPOSITION AND results obtained lead to the same formula. The optical activity observed by me, sp. rt. pr. [ a ] j = 135*3", agrees with the numbers obtained by Scheibler and Tollens, [ a ] j = 114.7" ; they evidently, in this case also, have made the calculation for the crystals, I f o r the dry substance : 114.7" for C18H32016,5H20, is equal to 135.1" for C1,H3,O,,.The sp. gr. of a solution containing 1 gram in 100 C.C. is higher than that given by Tollens ; his figures (Ber., 18, 2616) Ieading to a true sp. gr. 1.003712 for such a solution, my figure is 1.003956. The yield of muck acid is practically the same as observed by Berthelot, Scheibler, and Tollens ; my number is, however, a little higher than that published by Scheibler, 30 per cent. against 26.7, but I cannot say with the quantity I had to work with that my experiment can lay much claim to absolute accuracy. My observations on the products of inversion do not quite agree with those published by Tollens. He says galactose, dextrose, and I~vulose are the pro- ducts. I found, for the products of the action of' sulphuric acid, [aJj = 43*5", and K = 431 ; now, if we suppose that the remaining 15 non-K was unaltered sugar, and the 81 composed of equal parts of galactose, dextrose, and lawnlose, we get a mixture the optical activity of which works out [ a J j = 36*1", a figure sufficiently removed from 43.5" to throw some doubt on the supposition; how- ever, as I have not sufficient substance to settle the point a t present, I must leave it. These facts, then, leave no doubt that I have been dealing with the " raffinose " of Loiseau, which Tollens says is Berthelot's mellitose ; the source whence I isolated ;it seems to me of sufficient interest to record. [&ID = 104" ;

ISSN:0368-1645    

DOI:10.1039/CT8864900070

出版商:RSC    

年代:1886

数据来源: RSC

摘要:

74 ARMSTRONG AND MILLER: THE DECOMPOSITION AND X.- The decomposition, and< glenesis of hydmcarbons at high tempera- tures. I. The products of the) manufucture of gas front petroleum. By HENRY E. ARMSTRONG and A. K. MILLER. 1. A PRELIMINARY account of our work W ~ B given to t,he Society in June of last year (Ckem. News, 49, 285), a somewhat lengthy descrip- tion of the manufacture of gas from oil, as practised in this country, having been previously communicated by Dr. Armstrong t o the Society of Chemical Industry in a paper read before their London Section in April, and printed in their Journal for September, 1884 (pp. 462468). 2. The investigation was commenced several years ago, and wasGENESIS OF HYDROCARBONS AT HIGH TEMPERATURES. 75 carried on almost uninterruptedly during 1884 and the first half of 1885, but the products are so numerous and their separation and iden- tification is attended with such difficulty, that the progress made is far from satisfactory.Nevertheless, a stage has been reached a t which it appears desirable to record the results, as they are in part highly suggestive and will lead to new inquiries being undertaken ; besides which the methods at our disposal are scarcely sufficient to enable us to unravel the very tangled skein which the investigation presents. An abstract of the present paper is given in the number of the Abstracts of the Proceediings 0.f the Chemical Society for June 18th, 1885. 3. The products of the manufacture of oil-gas are historically of great interest, as their examination led Faraday, in 1825, to his momentous discovery of “ Bicarburet of Hydrogen,” now known as benzene.* Another new compound described in the same paper was obtained from the most volatile portion of the condensed liquor from the oil- gas receivers.According to Faraday’s analysis, it cozltai ned carbon find hydrogen in the same proportions as olefiant gas, but was of double the density. This is the composition of butylene, the dis- covery of which hasatherefore always been attributed to Faraday ; we shall have occasion later on to consider whether the evidence he adduces is sufficient to warrant this conclusion. Faraday ’s memoir agords a considerable amount of information which we think jestifies the inference that the oil-gas of the present day differs but little from that then made, although the oils now used are derived from shale and petroleum and it was then customary to use fish or vegetable<oil.4. We have not been able to ascertain that any attempt has been made to add to our knowledge of the chemistry of the subject since Paraday’s investigation was published, notwithstanding the attention paid within recent years totthe manufacture of oil-gas, excepting that Greville Williams appears to have commenced ,the examination of the bye-products of its manufacture not long after Dr. Armstrong had begun t o study them (Chem. News, 1884, p. 197 ; see also Jour. SOC. Chem. I n d . , 1884, p. 462). 5 . In describing our work we propose to disregard the order in which the various constituents were separated or identi6ed ; our main object being to throw light on the nature of the changes resulting from the decomposition of petroleum hydrocarbons a t high temperatures, it will be desirable to give a connected account of the observations relating to each of the series of hydrocarbons which occur in one or other of the products examined, viz., the compressed gas itself; * “ On new compounds of carbon and hydrogen, and on certain otlier products obtained during the decomposition of oil by heat :” a paper read June 16th, 1825, by M.Bsraday, F.R.S., &c., Phil. Trans., 1825, 44-466. G 276 ARMSTRONG AND MILLER: THE DECOMPOSITION AND the liquid deposited during compression of the gas, either in a chamber attached to the compressing pump or in the reservoir in which the gas is stored; and the tar which is deposited from the crude gas prior to compression.I n this paper, however, we shall deal only with that portion of the gas which is absorbed by bromine and with t.he steam-distillable portion of the tar. I. Benzenoid hydrocarbons. 6. The liquid deposited during compression of the gas is wholly volatile in steam when recently obtained, and consists of hydrocarbons capable of being polymerised by sulphuric acid, benzenes and a relatively very small proportion of hydrocarbons unattackable by sul- pliuric acid ; the last-mentioned constituents are present in larger quantity in the steam distillate from the tar. 7. On mixing either liquid with moderately dilute sulphuric acid (2 vols. acid 1 vol. water) much heat is developed, and by its action the unsaturated hydrocarbons are for the most part converted into compounds which are not distillable in steam ; in order to effect as complete a conversion as possible, it,, is desirable when the action appears to be a t an end to separate the acid from the oil and to treat the latter with stronger acid-4 : 1.In dealing with small quantities a glass stoppered bottle is used ; but for large qnantities it is well to use a copper can with a tightly fitting metal plug :. there is then no danger of the vessel bursting, and it is much easier to quickly cool the mixture. The acid should be added in small quantity a t first, and care should be taken in agitating ; in working with large quantities it is desirable to steam-distil as soon as the treatment with 2 : 1 acid is at an end, and to well mix the distillate with the stronger acid, as owing to the viscid character of the product it becomes very difficult to complete the conversion of the unsaturated hydrocarbons into polymerides.The steam distillate finally obtained has a peculiar characteristic unpleasant odour, due apparently to the presence of volatile products of the action of the acid. 8. A large quantity of benzene may be directly crystallised out from the product so obtained from the liquid deposited from the gas during compression in the manner first described by Faraday and made popular maDy years later by Mansfield. We have employed a very simple apparatus for the purpose, consisting of a cylindrical vessel, closed only a t the bottom, 12 inches high and 4.5 inches in diameter, made of brass & of an inch thick ; into this fits fitirly closely a similar cylinder, the bottom of which has numerous fine holes bored through it.The larger cylinder is placed in a wooden pail o r tub, surroundedGENESIS OF HYDROCARBONS AT HIGH TEMPERATURES. 77 with a good freezing mixture, and the hydrocarbon is then poured into i t ; the walls of the cylinder soon become coated with crystals, which are detached by means of a stout metal rod, and this is fre- quently used in stirring the contenti3 of the cylinder. When crystal- lisation is complete, the smaller cylinder is pushed down upon the crystalline pulp, the pail is placed between the jaws of an ordinary long carpenters' cramp, a blwk of wood is placed across the mouth of the inner cylinder, and pressure is gradually applied by turning the screw of the cramp.The expressed liquid is syphoned off as it rises into the interior of ,the cylinder. Pressure having been applied to a sufficient exhent and during a sufficient length of time, the screw is released, the ram witbdrawn, the cylinder lifted out of the freezing mixture, and the small amount of liquid floating on the solid cake is poured out; the benzene is then caused to melt by lowering into it a tube fitted up after the m n n e r of a wash-bottle, through which steam is being passed. If the mother-liquor from the crystals be fractionally distilled, and the portions boiling near to SO" be then treated as above described, a further considerable quantity of crystalline benzene may easily be obtained.I n like manner the lowest fractions of the product obtained on agitating the steam distillate from the tar with acid, &c., also yield benzene. The benzene thus separated is by no means pure, and should be treated with alkaline permanganate, bromine, or sulphuric acid, fractionally distilled, and again crystallised. 9. A9 much of the benzene as possible having been removed, the residue is now extracted with hot concentrated sulpburic: acid, and the benzenes are recovered from the solution by hydrolysis (Chem. Soc. Trans., 1884, 14s). The acid should be placed together with the hydrocarbon in a vessel which can be closed-a stoppered bottle if a moderate quantity is to be treated, or a copper can if the quantity be large. To ensure intimate contact, the vessel is then very vigorously shaken.In the first instance cold acid may be used, as heat is developed by the dis- solution of the more easily attacked liydrocarbons ; afterwards the mixture of acid and hydrocarbon should be heated to 60-70". An insufficient quantity of acid is used in the first treatment, and the unattacked hydrocarbon is afterwards shaken with fresh acid ; finally it is violently shaken with weakly fuming acid in order to remove all the benzene. Care must be taken in doing this, as the action of the fuming acid usually gives rise to the production of gas-sulphur dioxide. 10. The residual unattacked hydrocarbon is then mixed with a little78 ARMSTRONG AND MILLER : THE DECOMPOSITION AND alkali and steam-distilled ;. the product is a brilliant colourless liquid, having the pleasant sweet odour Characteristic of a pure paraffin.11. On hydrolysing the crude mixture of sulphonic acids, after the whole of the benzenoid hydrocarbons have been recovered, a consider- able amount of black carbonaceous matter remains with the acid ; we have always regarded lhis as formed from pmducts of the polymerisa- tion of unsaturated hydrocai*bons by the dilute acid during the first treatment. 12. The method described is that which renders it. possible to sepa- rate the whole of the benzenoid hydrocarbons from the original oil-gas products. Much of the benzene, may, however, be obtained without destroying the unsaturated hydrocarbons by refrigerating the appro- priate fraction of the liquid deposited on compression of the gas or of the steam distillate from the tar.And it is scarcely necessary to point out, that either separate fractions of the original crude materials, or the crude materials as a whole, may be submitted to treatment in the above manner. 13. To separate the vasous constituents of the complex' mixture of benzenoid hydrocarbons thus obtained, it is fractionally distilled. From the lowest, fraction a considerable amount of benmne may easily be frozen out. To separate the toluene, the fractiona boiling below 115", from which no more benzene can be obtained by refrigeration, are shaken with hot concentrated sulphuric acid : as benzene is less readily attacked than toluene, it is possible b j fractional treatment with the acid to dissolve chiefly the latter, leaving a residue from which a further quantity of benzene may be crystallised out.The mixture of sulphonic acids with sulphuric acid is poured into water, the solution neutralised with whiting paste, and the resulting calcium salts are then converted into potassium ~ a l t s , &c. ; the liquid when sufbiently concentrated deposits a large crop of the characteristic crystals of potassium tolueneparasulphonnte, which are recrystallised and hydrolysed to recover the toluene. 14. The xylenes were separated by Jacobsen's method (Ber., 10,1009) from the fractians boiling at 135-145'. Metaxylene was identified by conversion into its characteristic trinitro-derivative ; independent evidence of its presence was afforded by the production of metatoluic acid in large quantity on oxidation of the fractions collected between 135-145" of the original steam distillate from the nil-gas tar.Para- xylene was obtained as sodium paraxylenesulphonate, CsH,*SO,Na-H,O ; and paratoluic acid was obtained on oxidation of the hydrocarbon separated by hydrolysis of this salt. Orthozylene was separated in the form of the highly characteristic sodium orthoxylenesulphonate, CsH9+3O3Na*5H,O. The three isomeric xylenes appear to us to occur in the oil-gas product very much in the proportions in whichGENESIS OF HYDROCARBONS AT HIGH TEMPERATURES. 79 they ordinarily occur in coal-tar xylene, metaxylene being by far the most abundant, and paraxylene the least abundant. 15. Mesitylene and pseudocumene were separated from the frac- tions boiling bstween 155-175" by our method of fractional hydrolysis, the hydrocarbon being for this purpose dissolved in sulphuric acid, the solution diluted with water, and steam passed into it at a tempe- rature not exceeding 100-105".The hydrocarbon thus separated was then reconverted into sulphonic acid ; the barium salt of the acid was almost pure mesitylenesulphonate, ( C9HI,*S0&Ba*H,O, which ia a very characteristic salt. The equally characteristic potassium -salt was also prepared. After separation of the main bulk of the mesikylene, the tempera- ture was raised, and the whole of the hydrocarbon present separated by hydrolysis ; it was then reconverted into sulfphonic acid, and the latter several times recrystallised from. dilute sulphuric acid, as recommended by Jacobsen (Annulen; 184,198)~ In4his way a cansider- able quantity of pure pseudocumenesnlphonic acid was readily obtained.The hydrocarbon separated from it had a constant boiling point, and the trinitro- and tribromo-derivative prepared from i t had ?all the properties of these derivatives of pseudocemene. Mesitylene and pseudocumene are, we think, also present i n about the same relative proportions in oil-gas tar as in coal-tar, but itr'is much easier to separate them from the 'foamer on account of tlie absence of basic compounds. 16. The fractions 180-190" and 190-200" were- separately con- verted into sulphonic acid, from which barium salts were prepared ; the salts did not crystsllise well, separating from a hot solution in an apparently amorphous state.The dry salt was higbly pulverulent, and much like barium 1:2:3:5t;etramethylbenzenesulphonate. The salt obtained from the 180-190" fraction was found tcrcontain 23-97, 24.02, 23.81 per cent. of barium. Theory indicates the presence of 24-33 per cent. barium in the sulphonate of a hydrocarbon of the formula CloH,,. The magnesium salt of the sulphonic acid prepared from the 180--190" fraction crystallised well in flat needles, containing 84.6 per cent. water and 5.21 per cent. of magnesium ; a salt of the formula ( C~oH13*S03)2Mg*8H20 should contain 24.24 per cent. water and 5.33 per cent. magnesium. Magnesium pseudocumenesulphonate was prepared for comparison, and was found to be a very similar salt ; it contained 26.32 per cent. of water and 5.5G per cent.magnesium. A salt of the formula 2[ (C,Hl,-S0,)2Mg].1 7H,O would contain 26.61 per cent. water and 5.68 per cent. magnesium. A small quantity of hydrocarbon separated from the barium salt prepared from the 180-190" fraction boiled at 178-188", chiefly a t 180- 185". It gave a solid bromo-derivative which, after recrystalli-80 ARJISTROSG AND MILLER : THE DECOJlPOSITION AND sation from alcohol melted a t 215" ; after repeated recrystallisation the melting point rose to 232.5". The analysis of an impure portion of this bromide gave 64.59 per cent. bromine, but only 0.09 gram of substance could be used, and probably this contained tiibromopseudo- cumene ; the amount corresponding with the formula C,,,H,,Br3 is 64.69 per cent. bromine. In the barium salt prepared from the 180-200" fraetion 23.12 and 23.36 per cent.of barium was found ; a salt of the formula ( CllH15+303)2Ba should contain 23.36 per cent. barium. These facts leave little doubt that a t 1east.one benzene higher in the series than trimethylbenzene is contained in the oil-gas product. Probably isodurene is present, but unfortunately the amount at our disposal was insuEcient to enable us to prove this.* 17. A large quantity of naphthalene separates from the fractions collected above 200". After its removal a comparatively small amount of hydrocarbon is left. Benzene being present in sueh large amount in the oil-gas product, i t appeared not unlikely that diphenyl would also occur in them. Notlwithstanding persistent efforts to isolate this hydrocarbon, however, we have entirely failed to discover it in the portions boiling between 250-260".Hitherto, indeed, we have been unable to determine the nature of any of the benzenoid hydrocarbons of higher boiling point than naphthalene ; the quantity obt,ained is very small, and i t is imposfiible to separate a pure substance by distillation. 11. Hydrocarbons of the CaHZfi-2 Series. 18. The separation and identification of the unsaturated hydro- carbons other than those of the benzenoid series is compassed with diffi- culty. By determining the amounts of bromine required to saturate the various fractions, i t was in khe first instance ascertained that not only ole fines, but less saturated .hydrocarbons were present. Moreover, that there were no true acetj1,enes among these, that is, hydrocarbons of the form CH*C*C,HI,,,,, at Once appeared from the fact that ammoniacal cuprous and argentic solutions were without appreciable action upon the liquid condensed from the oil-gas.This conclusion was confirmed by the observation made both at the Mansion House Station Works of the Metropolitan District Railway Company and at the Stratford Works of the Great Eastern Company that the gas Since this paper was placed in the printer's hands, K. E. Scliulze has announced (Ber., 18, 3032) the discovery of 1:2:4:5tetramethylbenzene (durene) in coal- tar. It may be added that, in a paper read a t the last spring meeting of the Iron and Steel Institute, Dr. Armstrong stated that the oil from the Jarneson coke oren contained benzenes different from those in ordinary coal-tay.GENESIS OF HYDROCARBONS AT HIGH TEMPERATURES.8 1 itself produced but a very small amount of precipitate in an amino- niacal cuprous solution. 19. On warming the crude liquid obtained from the reservoirs in which the gas is stored, distillation a t once sets in, much gas being a t 6rst given off; this gas is absorbed by bromine. On steam-distilling the resulting bromide, less than two-thirds passed over as a colourless heavy oil ; the residue became almost entirely solid on cooling, and from it a pure substance was readily obtained by crystallisation from alcohol. In like manner by paFsing the compressed oil-gas into bromine, a liquid bromide was obtained which was for the most part easily volatile, only about 7 per cent. remaining when oil ceased to distil over; the residue partially solidified on cooling, and from it more tban half its weight of a solid bromide was obtained identical with that referred to in the previous paragraph.The bromide in question crystallised from alcohol in small, glisten- ing plates, exhibiting under the microscope a very irregular outline ; it fused a t 116", and volatilised with extreme slowness in 8 current of steam. The percentage of bromine in it, as determined by Volhard's method of combustion with potassium nitrake and sodium carbonate, &c., was found to be S5.99. HenCelthere could be little doubt that it was a tetrabromide of the formula CaH6Br4, the percentage of bromine in which is 85.55. Judging from its properties, the bromide thus obtained is identical with the crotonylene tetrabromide prepared by Caventou from the liquid deposited on compressing coal-gas.Theoretically, four distinct hydrocarbons of the formula c4H6 are possible, viz. :- 1. Ethylacetylene ................. 2. Dimethylacetylene ............... CMe-CMe. 3. Methylallene ................... CHMe.C*CH2. 4. Vinylethylene (dirnethyleneethane) CH,*CH*CH*CH,. CH-CE t . Ethylacetylene is exclnded, as our hydrocarbon is not a true acetpl- ene; the hydrocarbon obtained by Caventou from crude butylene bromide gave a tetrabromide which volatilised somewhat readily in the air, and from Almedingen's experiments there is every reason to suppose that this hydrocarbon was dimethylacetylene (Ber., 14, 2073). By distilling erythrol with formic acid, Heninger obtained a hydrocarbon of the formula C4H6 yielding a bromide similar to that prepared by ourselves and apparently identical with that obtained by Caventou by the decomposition of fuse1 oil a t a red heat and from coal-gas : as this hydrocarbon is formed from erythrol it may almost certainly be regarded as dimethyleneethane or vinylethylene.On inspection of the four formuls it will be obvious that a study of the82 ARMSTRONG AND MILLER: THE DECOMPOSITION AND oxidation-products is calculated to afford the required proof : vinyl- ethylene should not yield acetic acid, which would, however, be a product of the oxidation of both dimethylacetylene and methylallene ; and ethylacetylene forms propionic acid. 20. To obtain the hydrocarbon for oxidation, we have employed a method which we believe will in the future be of great service in the investigation of unsaturated hydrocarbons.The usual practice is to withdraw the bromine from the bromides of these hydrocarbons by means of sodium, but there are numerous objections to this method : in many cases the change takes place only with difficulty and at a high temperature ; in others secondary products are formed owing to the high temperature locally developed ; and the sodium usually becomes coated with a protecting layer of bromide. It occurred to us that Gladstone and Tribe’s zinc-copper couple might be used with advantage, they having already shown that ethylene and propylene bromides are readily deprived of their bromine by its action in pre- sence of alcohol (Chem.Xoc. J., 1874, 406). The results have entirely surpassed our expectations; as in all cases hitherto examined we have olitained a practically theoretical yield of hydrocarbon by merely warming the bromide with alcohol and the couple. Moreover, the hydrocarbon thus recovered has always been found to be identical with that used in preparing the bromide-that is, it again yields the same bromide. Unfortunately this method was not made use of until nearly the close of our experiments ; had we known of it earlier, we feel sure that we should have been in a position to throw far more light on the nature of the products of the oil-gas manufacture. We may add that it is our intention fully to inquire into the application of this method to the separation of unsaturated hxdrocarbons from their compounds with halogens.21. The oxidation of the hydrocarbon separated from the bromide C,,H,Er., by the action of the zinc-copper couple was effected by displacing part of a 2 per cent. solution of potassium perman- ganate from a bottle full of it by means of the gas from 50 grams of the bromide-the gas having been collected over water in a holder and left for some time in contact with the water to remove alcohol-vapour. The permanganate was vigorously shaken to bring it into contact with the gas, and the oxidation being completed, sulphuric acid was added and the volatile acid removed by steam- distillation. The distillate was neutralised by the addition of about 1.6 gram of sodium carbonate ; the neutral liquid having been con- centrated, the required amount of silver nitrate was added, and the solution boiled : an amount of silver was precipitated practically equivalent to the silver nitrate used, and no trace of acetate could be detected in the filtrate.GENESIS OF HYDROCARBONS AT HIGH TEMPERATURES. 83 As formic acid is its oxidation-product, there can be no doubt that the hydrocarbon of the formiila CaH, from oil-gas is dimethylene- ethane or vinylethylene, CH2*CH*CH*C-H2.22. On steam-clistilling the bromides prepared from the fractions of the original liquid from the oil-gas reservoir collected within a few degrees on either side of 40°, dark-coloured viscid residues were obtained in which crystds gradually formed. It was easy to separate these mechanically, and to purify them by recrystallisation from alcohol.The pure substance crystallised in long, thin, narrow, well- defined prisms, melting a t 115". Analysis gave results agreeing with the formula C,H,Bra ; thus :- Subs. 0.1982 7 ) 0.2210 ,) ,02441 ), 0.2544 7, 0.2083 ,, 0,2612 7 7 09278 ,, 0.2612 ), 0.2278 AgBr 0.3828 ,, 0.4284 ,, 0-4935 ,) 0.4021 H,O 0.0471 ,, 0.0544 COO 0.1322 ,, 0.1526 ,) 0.4734 c, .......... 59.85 H, .......... 8-00 BrA.. ........ 319.04 Bromine per cent. 83-19 7 7 7 7 7 ,7 Hydrogen Carbon ,, 7 9 Percentages. 15.47 2.07 82-46 ,) 82.49 7 7 82-53 ), 82.55 ,, 82.15 I ! 2.30 7 7 2.31 ,) 15-82 7 ) 15.93 Mean results. 15.87 2.30 82.38 386.89 100~00 100.35 23. The hydrocarbon was separated from this bromide by warming it with the zinc-copper couple and alcohol ; the amount obtained was almost the theoretical.After several days' digestion with calcium chloride in a sealed tube it was distilled ; it boiled almost constantly a t about 45", leaving a few drops of a syrupy residue which exploded when heated on platinum, in this respect behaving somewhat like isoprene. It had the peculiar alliaceous odour so characteristic of the crude liquid deposited from oil-gas. It was reconverted into the original tetrabromide on careful treatment with bromine. J t was readily oxidised by a 4 per cent. solution of potassium permanganate : more than half of the volatile acid produced was formic acid, the rest being pure acetic acid. Five hydrocarbons of the formula C5H, are at present known: propylacetylene, isopropylacetylene, ethylmethylacetylene, piperylene and isoprene; ours appears to be a sixth.The first three o€ these are excluded from consideration on account of their behaviour on84 ARMSTRONG AND MILLER : THE DECOMPOSITION AND oxidation ; moreover, mr hydrocarbon is not a true acetylene, and cannot, therefore, be either propyl- or isopropyl-acetylene. Piperylene, according t o Hofmann (Ber., 14, 665), forms a tetrabromide crystal- lising from alcohol in glistening pZates. Isoprene yields a liquid bromide. Eight modifications in all are possible of a hydrocarbon of the formula C,H,; three of these are derived from acetylene ; the formulee of the remaining five are as follows :- cH2 c Hs ( 3 x 3 c H3 C(CH3)Z c H CH CH2 CH c H2 CH CH c: CH GHZ CH, C Hz c H3 CHz CH C c CH2 Allylethylene. Isoallylethylene.Ethylallene. Synimetrical Unsymmetrical dimethyl- dimethylnllene. nllene. Piperylene, according to Ladenburg (Bey., 16, 2059) is allylethylene ; and that this is not the composition of our hydrocarbon may be inferred from the fact that it yields acetic acid on oxidation. Ethyl- allene is also excluded as it would furnish propionic acid on oxidation. But three formula remain therefore, and we incline to select that of isoallylethylene on account of the simple relation which this hydro- carbon bears to normal amylene, from which probably our hydro- carbon is immediately derived :- CH3* CH,*CH,*CH* CH, = Propyle thylene. CH,-CH*CH*CH*C)H, = Isoallylethylene. If our argument be correct, isoprene must be either symmetrical or unsymmetrical dimeth y Zallene ; taking into consideration all that is known of the terpenes-to which it is so intimately related- the latter is the more probable.We are now engaged in the study of the hydro- carbons of the formula C5H, in the hope of solving this problem, which is one of considerable importance in connection with the ques- t$on of the constitution of the hydrocarbons of the formula CloH,,. 24. A faulty determination of bromine, made by Volhard's method, led us, in the first inst'ance, to regard the bromide just described as identical with Schorlemmer's so-called hexoylene tetrabromide, C,H,,Br4, whose description of this compound tallies very closely with that which we have given of our tetrabromide. Schorlemmer prepared his substance from a fmction boiling at about 80" of the more volatile products of the distillation of boghead cannel ; to this he added bromine in excess, and after removing the greater part of the admixed benzene by distillation, he heated the bromide with sodium t o regenerate the hydrocarbon ; this was again brominated.GENESIS OF HYDROCARBOXS AT HIGH TEMPERATURES. 85 The product was an oil from which the solid gradually crjstitllised out.It may be mentioned that Schorlemmer bases the formula C,H,,Br, on a single determination of bromine in only 0.1970 gram of substance. I n the hope, therefore, of obtaining hexoylene we very carefully fractioned out a portion boiling a t about 80-82" from our crude material, and this was brominated ; on steam-distilling the product much benzene passed over, then an oily bromide heavier than water, a moderately limpid dark-brown oil remaining ; no crystals whatever separated from this, and i t was therefore submitted to the action of the zinc-copper couple in presence of alcohol, The re- generated hydrocarbon wag again brominated and steam-distilled ; very little came over.A minute quantity of solid was, however, deposited in the condenser. The experiment was repeated with a considerable quantity of the fractions collected at 70-80" : after adding excess of bromine, the product was steam-distilled until exhausted ; traces of a solid. were again obtained. On extiacting the residue with alcohol coniparatively little dissolved and no crystals could be obtained from the alcoholic extract: the final residue was a carbonaceous mass.The solid referred to crystallised from alcohol in small, hard, well-formed, short prisms melting at, 185"; the quantity obtained was too small even for an analysis. 25. In all cases, on steam-distilling the crude bromides from the various fractions, decomposition was observed to take place more o r less; and the non-volatile residue from all but the lowest fractions was more or less carbonaceousj and alcohol extracted but very little oily matter, leaving a friable residue. The bromides which are thus decomposed are probably derived from hydrocarbons of the ClrH2n--2 series-or in part perhaps from less saturated hydrocarbons-such as Schorlemmer has shown to be present in cannel oils. The polymer- ides obtained by means of sulphuric acid were precisely of the character of those described, by Schorlemmer (Annulen, 1866, 139, 244).111. Hydrocarbons of the Ole$ne group. 26. Indication of the presence of these hydrocarbons is afforded by the behaviour with bromine especially of the lowest fractions of the " hydrocarbon " deposited during compression of oil-gas ; these frac- tions, if free from benzene, are entirely converted into polymerides and soluble bodies on treatment with sulphuric acid : they therefore con- sist of unsaturated hydrocarbons, but the amount of bromine which they will absorb is far less than would be the case if they contained only hydrocarbons less rich in hydrogen than the olefines. To isolate the pure olefines from mixtures such as those with which86 ARMSTRONG AND MILLEK: THE DECOMPOSITION AND we have had t o deal, no ordinary method will suffice ; had we become aware that the zinc-copper couple was applicable to the separation of unsaturated hydrocarbons from their bromides at an early stage instead of almost at the close of this portion of the investigation, it would undoubtedly have been possible to isolate the olefines ; but as it was we were obliged t o content ourselves with the proof that ole- fines mere present, and with an indirect determination of their nature.The method followed consisted in oxidising the various fractions by agihtion in a stoppered bottle with a cold 4 per cent. solution of potassium permanganate. I n selecting this method of treatment we were guided by the knowledge that the normal olefines-those of the type C,,H2n+ldH*CH2-are converted by oxidation into acids of the acetic series of the type C,H?n+lCOOH, the CH, group being elimi- nated as formic acid ; only true acetylenes-Le., hydrocarbons of the formula C,,,H,,+lC*CH-yield similar products, and, as these were known to be absent from our crude material, the production of the corresponding acid from a fradion of about the boiling point of any particular normal olefine would be conclusive proof of the presence of that olefine.Thus the normal amylene fraction should yield butyric acid, the normal hexylene fraction valeric acid, &c. The appropriate fractions having been oxidised, sulphuric acid was added, and the volatile acid separated by steam-distillation ; the dis- tillate was neutralised with sodium carbonate, concen trated, and then fractionally precipitated with silver nitrate ; the silver precipitates weye fractionally extracted with water, the solutions well boiled to decompose formate, and the dissolved salts crystallised out and analysed.When a silver salt of constant cotnposition was obtained, it was converted into the calcium salt, as tbe lower normal primary acids of the acetic series all furnish characberistic calcium salts. 27. The amylene, hexylene, and heptylene frautions treated in this way gave respectively normal butyric, normal valeric, and normal caproic acids. The higher fractions were similarly treated, but repeated experi- ments failed to yield any indication whatever of the presence of ole- fines higher than heptylene: formic and acetic were the only volatile paraffiiioid acids produced-these being associated with the oxidation- products of the benzenoid hydrocarbons present in the fractions examined.A very careful study of all the various fractions obhained has con- vinced us that besides the three normal primary olefines above men- tioned, no other hydrocarbons of the C,H2, series, or indeed of any other parxffinoid series, can be present, except such as yield acetic and formic acids on oxidation ; and we have no reason to suspect that any olefines other than those mentioned are present in the liquidGENESIS UF HYDROCARBONS AT HTGH TEMPERATURES. 87 products from the manufacture of oil-gas : our opinion being that the acetic acid obtained was derived from hydrocarbons less Raturated than the olefines. 28.We have already referred to the presence of the hydrocarbon C4H6 in the compressed oil-gas (9 19), and to the manner in which it was separated from the crude mixture of bromides obtained on passing the gas into bromine. On distilling the steam-distillate from this mixture of bromides some hydrogen bromide was evolved, but after a few distillations the constituent yielding this gas was practically all decomposed. By far the largest amount of the bromide separated by fractional distillation had about the boiling point of ethylene bromide, and a considerable quantity of this compound was crystallised out from this portion of the distillate by refrigeration. 29. The next largest fraction had about the boiling point of methyl- ethylene (propylene) bromide, and we have no doubt that it mainly consisted of this cornpoutid, as acetic acid was obtained in large quantity by direct oxidation of this fraction with permanganate. 30.Ethylene and propylene having thus beendetected in the oil-gas, and normal amylene, hexylene and heptylene in the liquid deposited from it, it was to be expected &at normal butjiene was also present. A quantity of abwt 4000 gmms of bromides from the gas gave, however, but a relatively small quantity boiling a t a higher tempera- ture than propylene bromide,.and as it was impossible to separate A pure product by distillation, the various fractions were directly oxidised with permanganate. 59 grams laoiling a t 148-153” The quantities used were :- 42 9 7 ,, 153-158 14 ,. ,, 158-164 5 1 9 , ,, above.164”. The acid distillate was t r e a t d with ledoxide in the manner recom- mended by Linnemann (Amalen, 160, 222), in order to separate pro- pionic acid, but this acid could not be detected ; in fact,.onlg acetic and formic acids were formed.We have before mentioned that a considerable quantity of bromides was obtained by passing into bromine the gas given off when we began to distil the liquid deposited from oil-gas on compression, and that a t least two-thirds of this was volatilised on steam-distillation, the residue consisting mainly of crotonylene tetrabromide ; it is pos- sible that the portion of the mixture of bromides volatile with water- vapour contained butylene bromide, b u t most unfortunately the whole of this material was lost in the fire which occurred in the laboratory of the London Institution during the course of the investigation. As butylene has a much lower boiling point than crotonylene, we88 ARMSTRONG AND MILLER: THE DECOMPOSITION AND should certainly expect to find its bromide among those obtained from oil-gas itself, as a considerable quantity of crotonylene tetrabromide is present ; our failure to detect it has led us to consider the evidence advanced by Faraday upon which the discovery of butylene among the oil-gas products is at,tributed to him, and we are of opinion that it is by no means conclusive."If a portion of the original liquid be warmed by the hand, or otherwise, and the vapour which passes off be passed through a tnbe a t 0" (Fahr.), very little condensed vapour will go on to the mercurial trough, but there mill be found after a time a, portion of fluid in the tube distinguished by t h e following properties.Though a liquid at O", it upon slight elevation of temperature begins to boil, and before i t has attained 32" is all resolved into vapour or gas. . . . . The sp. gr. of the portion I obtained was between 27 and 28, hydrogen being 1. . . . . When cooled t o 0" it condensed again, and inclosed in this state in a tube of known' capacity and hermetically sealed up, the bulk of it given weight of t6e substance a t common temperatures was ascertained. This compared with water gave the sp. gr. of the liquid as 0.627 at(54". . . . . Alcohol dissolves it in large quantity. . . . . Sulphuric acid condenses the gas in very large quantity : 1 volume of the acid condensing above 100 volumes of the vapour.Great heat is produced during the action; no sulphurous acid is formed ; the acid is much blackened, has a pecu- liar odour, and upou dilution generally becomes turbid, but no gas is evolved. A permanent compound of the acid with carbon and hydrogen is produced, and enters- as before mentioned into combina- tion with bases. A mixture of 2 volhmes of this vapour with 14 volumes of pure oxygen was made, and a portion detonated in a eudiometer- tube; 8.8 volumes of the mixture diminished by the spark to 5.7 volnmes, and these by solution of potash to 1.4 volumes, which were oxygen. Hence '7.4 volumes had been consumed, consisting of :- His words are as follows :- . . . . Vapour of substance .....................1.2 Oxygen ................................ 6.3 Carbonic acid formed. .................... 4.3 Oxygen in carbonic acid .................. 4.3 Oxygen combining with hydrogen. ......... 2.0 Diminution by spark ..................... 3.1 This is nearly as if 1 volume of the vapour or gas had required 6volumes of oxygen, had consumed 4 of them in producing 4 of car- bonic acid gas, and had occupied the other 2 by 4 of hydrogen to form water. Upon which view 4 volumes or proportionals of hydrogen = 4, are combined with 4 proportionals of carbon = 24, to formGENESIS OF HYDROCARBONS AT HIaH TEMPERATURES. 89 1 volume of the vapour, the specific gravity of which would therefore be 28. Now this is but little removed from the actual specific gravity obtained by the preceding experiments; and knowing that this vapour must contain small portions of other substances in solution, there appears no reason to doubt that, if obtained pure, it would be found thus constituted.. . . . Chlorine and the vapour were therefore mixed in an exhausted retort : rapid combination took place, much heat was evolved, and a liquor produced resembling hydro- chloride of carbon, or the substance obtained by the same process from olefiant gas. . . . . Further, it was composed of nearly equal volumes of the vapour and chlorine ; it could not, therefore, be the same as the hydrochloride of carbon from olefiant gas, since it contains twice as much carbon and hydrogen.” Taking into account our own observations, especially the fact that we have failed to detect butylene although crotonylene was obtained in considerable quantity, we are inclined to think that Faraday was the discoverer of crotonylene rather than of butylene.It is obvious that he could not have had a pure substance for examination; the ratio of the density of his gas to that of hydrogen was between 27 and 28, and these are numbers which represent the relative density of crotonylene and butylene respectively ; the results of his combustion- analysis are almost equally compatible with either formula, CaHs or C4Hs, always bearing in mind that probably both propylene and amylene were present as impurities; we are not aware that the behavionr of butylene with sulphuric acid has been studied, but it is scarcely probable that it would be so readily absorbed as Paraday describes ; khere remains but one fact which undoubtedly lends sup- port t o the conclusion that it was butylene, viz., that on mixing it with chlorine a chloride was formed, “composed of nearly equal volumes of the vapour and of chlorine.” Our proof of the absence of butylene, it should be added, holds good only on the assumption that the butylene present is athylethylene, as the two dimethylethylenes would yield acetic acid on oxidation.As, however, all the olefines which are proved to have been present are represented by the formula C,Hz,+l*CH*CHz, it does not appear probable that the butylene would form an exception, especially as the crotonylene which is so abundantly contained in oil-gas is indubitably a derivative of normal butylene.I V . Hydrocadons insoluble in sulphuric acid. 31. Our method of separating these hydrocarbons has already been described (§§ 7-10). They are contained almost exclusively in the portion boiling above 150” of the steam-distillate from oil-gas tar : for example, about 1800 C.C. of fractions boiling at 105-130” gave after VOL. xmx. H90 ARMSTRONG AND MILLER: THE DECOMPOSITION AND exhaustive treatment with sulphuric acid only 6 grams of insoluble hydrocarbons boiling at about 125-140'. As far as possible, with the limited amount of material at our dis- posal, the attempt was made to separate the mixture into its con- stituents by fractional distillation ; but no very decided separation was accomplished. Three fractions were analysed with the following results :- 160-165O.180-185". 200-205". Carbon percenhge . . . . . . . . 85.33 85.37 85.27 85.26 85.70 - 85.63 85.50 - 85-39 Hydrogen percentage.. . . . . 14.80 14.74 14.32 0" R,elative density, - 0" .'... - - 7 , 9 , ...... - 14.73 - 0.7775 0.7886 0.8050 9 , 20" 0.7637 0.7768 0.7980 " 20" . . " * The general mean of the eight carbon determinations is 85.43 per cent., and of the four hydrogen determinations% 14.63 per cent. These numbers are very nearly those which correspond to the formula C,H,,,, viz., 85.56 per cent. carbon and 14.32 per cent. hydrogen, A paraffin of the formula CloH2, contains only 84.47 per cent. carbon and 15.53 per cent. hydrogen ; while even that of the formula CL2H26 con- tains but 84-67 per cent. carbon and 15.33 per cent. hydrogen. The conclusion that our products did not in the main consist of hydro- carbons of the CnH2)r+2 type is confirmed by the comparison of our determinations of relat'ive density with the data given by Krafft ( B e y ., 15, 1687) for the normal parafins :- B. p. Density at 0". Density a t 20". CloHz2 . . . . . . . . 173.0" 0.7452 gram. 0.7304 gram. C11H2, .. . . . . .. 194.5 0.7557 ,, 0.7411 ,, C12H,, . . .. . . . . 214.5 0.7655 ,, 0.7511 ,, Our figures are in every case considerably higher, and the difference would be greater if a strict comparison were made by calculating the densities corresponding to our relative densities. We are satistied that this is not due to the presence of benzenoid hydrocarbons, as special care was taken to remove these by treatment with fuming sulphuric and nitric acids followed by distillation from sodium.* As a warning t o those who, like myself, are in the habit of using c2mpressed oxygen for combustions, I may mention that several hydrogen deterininations were lost, owing, as was afterwards discovered, to the presence of traces of hydrogen in the oxygen.-H. E. A.GENESIS OF HYDROCARBOXS AT HIGH TEAIPERATURES. 91 Our figures more nearly agree with those given by Markownikoff and Oglobine (Ann. Chim. Plz,ys., 1884 [6], 2,372) for the C,H,, hydro- carbons which they separated-probably in a state of only approximaDe purity-from Russian petroleum :- B. p. Density at 0”. C10H20.. ........ 161” 0.795 gram. CllHzz.. ........ 180 0.8119 ,, C12H24.. ........ 196 0.8025 ,, Hence we are of opinion that the portion icsoluble in sulphnric acid of the steam-distillate from oil-gas tar which we have examined con- tained both true paraffins and pseudoZeJiizes such as mainly compose Russian petroleum, the latter being probably the principal con- stituents.V. Summary a d discussion of r e s u l t s . 32. Thus far we have been led to recognise among the products of a. Paraffins, of which traces only may be said to be present. b. “ PseudoleJnes,” that is, saturated hydrocarbons of the CnH2,* series such as occur in Russian petroleum ; these also are present in relatively small amount. c. Olefines, viz., ethylene, propylene, normal amylene, normal hexylene and normal heptylene, all higher homologues being absent. Ethylene is an important constituent of oil-gas as used, and so also apparently is propylene.The liquid deposited from the crude gas on compression is moderately rich in amylene, hexylene and heptylene. d. “ Psevdacetyleize.~,” viz., crotonylene (dimethyleneethane), CH2*CH.CH*CH2, and isoallylethylene, CH3*CH*CH*CH*CH2. The former is probably an important constituent of the gas, being of high value as an illuminant. Besides these two, both the liquid deposited on compression of the gas and the tar are rich in hydrocarbons identical with, or very closely related to, those discovered by Schor- lemmer in cannel oils. e. Benzenoid hydrocarbons, vie., benzene, toluene, the three isomeric dimethylbenzenes, the two trimethylbenzenes-pseudocumene and mesitylene-and naphthalene ; the first mentioned is a specially im- portant constituent in point of quantity.There is reason to believe that other benzenoid hydrocarbons besides these are present, even in the portions of the tar volatile with steam. 33. We have had the opportunity of examining various samples of the oil-shale oil or crude petroleum-used at the works from which we have obtained our materials, and have satisfied ourselves that the the manufacture of oil-gas the following hydrocarbons :- H 292 ARMSTRONQ AND MILLER: THE DECOMPOSITION AND proportion of constituents in them volatile with water-vapour was small, and that they were of a different character from those met with in the bye-products from the manufacture ; we have therefore little doubt that practically all the above-mentioned substances are pro- duced in the course of the manufacture of the gas, 34.The paraffins are probably formed in the manner indicated by Thorpe andYoung (Proc. Roy. Soc,, 1873, 21, 184), although it is pos- hible that they are in part original constituents of the oil used. It is, however, noteworthy that whereas Thorpe and Young in their inves- tigation of the decomposition of solid paraffins by heat obtained mixtures of lower paraffins and olefines almost in equimolecular pro- portions from pentane upwards, our material, although rich in nmylene and its next two homologues, has not been found to contain the corresponding paraffins. 35. The " pseudolefines " are also more probably products of change than original Constituents. But it is to be remembered that accord- i n g to Beilstein and Kurbatow (Ber., 13, ZOSS), American petroleurn contains hydrocarbons of the C,H2, series similar to those in Russian petroleum: hence, assuming our view to be correct, the question arises whether the pseudolefines are formed by simplification of higher pseudolefines or by the removal of hydrogen from corresponding para5ns.Theoretically this question is one of considerable import- ance, and we are therefore making it the subject of special experi- mental study. 36. The presence of olefines in products of the distillation of camel, of coal and of paraffin, has been established by various observers, but no proof of their nature had hitherto been given; it is therefore a matter of interest that those detected by us are all of the type 37. Regarding the hydrocarbons of the C,H2,-2 series, it is to be noted that vinylethylene is present in much larger proportion than isoallyl- ethylene, and hence it may be inferred that the former is a much more stable compound.Judging from the behaviour on oxidation of the remaining unsaturated hydrocarbons, which it is to be assumed are t o a large extent also members of the C,H2,,, series, it appears probable that they are formed from corresponding normal para5ns by processes similar to those by which these paraffins are converted into normal olefines and by which vinylethylene and isoallylethylene are formed from the corresponding normal olefines or paraffins. 38. Since Berthelot's discovery of the formation of benzene from acetylene, the benzenoid hydrocarbons have always been regarded as built up from true acetylenes (comp. Jacobsen, Ber., 10, 853). The fact that true acetylenes are all but absent from oil-gas and the bye- products of its manufacture would lead us to doubt whether this is CnH2, + 1 C H* C H2.GENESIS OF HYDROCARBONS AT HIGH TEMPERATURES. 93 so entirely the case; and the question arises whether these hydro- carbons may not also be directly descended from corresponding parafins : whether, for example, benzene may not be obtainable directly from hexane by withdrawal of hydrogen. It is sufficient to point this out, and it would be useless to further discuss the questiou ; but we shall endeavour to solve it by experiment. It will suffice to have pointed out thus briefly the various problems which await experimental investigation arising out of the examina- tion of the products of the decomposition of petroleum hydrocarbons in the manufacture of oil-gas. By continuing the examination of these products, and also by the study of the changes undergone by a material of more definite composition than the oils used for the pur- pose, viz., solid paraffin, we hope to obtain facts which will serve to elucidate the nature of many of the changes in hydrocarbons which occur at higher temperatures. The subject is one of very great importance, both as bearing on the discovery of rational methods of coking coal and of manufacturing illuminating gas and also hydro- carbons such as benzene, naphthalene and anthracene. It has undoubtedly also a bearing upon the question as to the origin of the complex mixtures of hydrocarbons such as constitute the different varieties of natural petroleum. Dr. A.rmstrong has in his previous paper expressed his thanks to various gentlemen connected with the Great Eastern and Metro- politan District Railways for aid afforded him in carrying out this investigation. We desire on this occasion, however, to thank Mr. W. F. Pettigrew, Engineer in charge of the Great Eastern Com- pany’s oil-gas works, for his ever-ready assistance during the past year. City and Oziilds of London Irtstitate, Central Institution, December, 1885.

ISSN:0368-1645    

DOI:10.1039/CT8864900074

出版商:RSC    

年代:1886

数据来源: RSC