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Proceedings of the Chemical Society, Vol. 10, No. 141 |
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Proceedings of the Chemical Society, London,
Volume 10,
Issue 141,
1894,
Page 151-170
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摘要:
Issued 19/i/1894 PROCEEDINGS OF THE CHEMICAL SOCIETY. No.141. Session 1893-94. June 21st, 1894. Dr. Armstrong, President, in the Chair. Mr. E. F. Harrison was formally admitted a Fellow of the Society. Certificates were read for the first time in favour of Messrs. Alexander Cameron, 13, Stonenest Street, Tollington Park, N ; Charles A. Fogg, 48, Kent Street, Bolton. Of the following papers those marked * were read :-*31. “A specimen of early Scottish iron.” By Margaret D. Dougd. The specimen was found on the site of the Fasagh bloomeries, on the north-east shore of Loch Maree, Ross-shire-the neighbour-hood where the manufacture of iron in Scotland appears to have had its rise nearly three centuries ago. Full particulars of the mechanical cha,racters, determined by Professor Unwin in the engi- neering laboratory of the Central Institution, are given in the paper, as well as the details of the chemical analysis.Its chemical composition was C = 0.192 ; Si = 0.077 ; S = 0.012 ; P = 04N7 ; Mn = 0.038; Ti = 0.002 ; Te = 99.770 ; Total = 100.178. From a report by Mr.Ames, the art-metal worker, the metal was of excellent quality, resembling the famous Swedish iron used by the English smiths of the 17th and 18th centuries. “32. “The interaction of sulphide with sulphate and oxide of Lead.” By J. B. Hannay. In this paper the author examines the equations suggested by Percy to account for the smelting of lead in the reverberatory furnace. The two main reactions which are supposed to occur are usually represented by the equations PbS + PbXOa = 2Pb + 2S02, 152 and PbS + 2Pb0 = 3Pb + ,SO2; and although Percy relies on the first as representing what takes place, he also says that a mixture of the sulphate and oxide reduces the sulphide.The author finds thst a much more complex reaction takes place, since metallic lead, when formed, attacks the remaining sulphate, producing litharge, wbich in its turn reacts with the sulphide, while some of the sulphide is removed by being dissolved in the metallic lead, and some is vola- tilised as the volatile compound PbS202. The result varies accord- ing to temperature and the method of mixing the substances. The following equations correspond with the results the author has ob-tained :-(1.) Lead sulphide and sulphate mixed in molecular proportions and very finely ground, and brought to calm fusion :-12PbS + 12PbSO4 = 11Pb + 2PbS + 6Pb0 + 2PbS + SPbSO, -L .I Hard lead. Slag. + PbS202 + 16S02 -/Fume. 34% per cent. of lead was obtained instead of 76.5 as required by Percy’s equation. When the sulphide of lead is in small pieces, the reaction yields more lead, but otherwise pursues a similar course :-(2.) l2PbS + 12PbSOa = 14Pb + 2PbS + 4Pb0 + 2PbSO4 + PbS L-T--J v + PbS2O2 + 17x02. L-d With excess of sulphate the result is:- (3,) 15PbS + 12PbS04 = 15Pb + 3PbS + 4Pb0 + 2(PbS*PbO) + PbS20, + 2050,. -On fusing lead sulphide and adding solid sulphate, the result is :-(4.) 3PbS + 3PbSOk = 3Pb + 2Pb0 + PbSzO, + 4S0,.-On fusing the sulphate and adding solid sulphide, the result is :-(5.) 15PbS04+ 5PbS = 12Pb0 + 4PbS0, + 4PbS202+ 8S02. -The temperature in this last case was much higher owing to the high melting point of the lead sulphate, and thus a larger amount of fume was produced. 153 On mixing sulphate and oxide in the proportions which ought to form lead and sulphur dioxide, as by the equation :-12PbS + 6PbS0, + 12Pb0 = 30Pb + 18S02, no such result was obtained, but the reduction took this form :-12PbS + 6PbSOa + 12Pb0 = 16Pb + PbS + The author has shown in another paper, that the sulphide and oxide do not react to form lead, bnt combine together to form the sub- stance PbS*PbO, which is the basis of lead slags.DISCTXSION. Professor ROBERTS-AUSTENsaid that it would be within the recol- lection of the Fellows of the Society, that when Mr. Hannay’s paper was read, on the 27th of May last, he pointed out that Mr. Hannay would be doing good service if he really added to our knowledge of the condensible products formed during lead smelting. Professor Austen, however, considered that the author’s views had been stated in such a, way as to fully justify chemists in asking for further evidence. The next morning Professor Austen had begun certain experiments on the lines indicated by Mr. Hannay. The President, also, appeared to have attacked the question, with the advantage of the co-operation of Mr. Hannay. Mr. Hannay’s statements presented themselves under two main aspects. It might be well either (1)to test the accuracy of his views :ts to the action of atmospheric air on sulphide of lead, or (2) to endeavour to obtain evidence as to the existence of volatile gaseous compounds of sulphide of lead. The speaker had adopted the latter course.He stated that he had under- stood Mr. Hannay to say distinctly, that if a mixture of sulphide and sulphate of lead were heated strongly no reaction ensued; hence Professor Austen’s appeal in favour of the accuracy of certain of the equations which were given by Percy and accepted by metallurgists. He was glad, however, to find that Mr. Hannay did not maintain this extreme view. Professor Austen had experimentally confirmed the fact that the following equation is substantially correct :-PbS + 3PbSOa = 4Pb0 + 4S0,.This is a very important point, as it is one of Percy’s main equations; but he had pointed out on the previous occasion, that both this equation and the one which has hitherto represented the reaction between oxide and sulphide of lead are strongly endothermic, and in the case of an endothermic equation some explanation had to be sought ; energy in some form had to be imported into the system, and an endothermic equation would represent, a reaction which would be less likely to take place at a low than at a high temperature. In the case of the well known endothermic interaction between carbon and the oxides of iron, it was probable that the iron carbonyl played an im- portant part, which certainly pointed to the possibility of similar action on the part of gaseous metallic compounds in the metallurgy of lead.It had, therefore, appeared to him that the conditions should be carefully studied ; and. he proceeded to state the results of the experiments he had instituted. First as regards the volatility of lead sulphide in various gases. The well known statement, "that the volatilisation of sulphide of lead is promoted by currents of gas, such as proceed from the combustion of fuel," a statement made by Dr. Percy in 1870, might well be taken as a starting point. There could be no doubt that when galena is strongly heated in a porcelain tube between two plugs of asbestos in a current of sulphur dioxide, the galena is volatilised, and is driven right through the plugs, con- densing on the other side of them.Such experiments were made in the School of Mines laboratory, the temperature being carefully measured by the aid of a thermocouple, and it was found that at a temperature of 1357" C., 9 grams of galena lost 38.2 per cent. of its weight in sulphur dioxide in 20'; while 9 grams of galena lost 37.7 per cent. in nitrogen in 20'. At a still higher temperature, 1434"C., 9 grams of galena lost 50.2 per cent. of its weight in sulphur dioxide in 20'; while 9 grams of galena lost 72.3 per cent. of its weight in nitrogen in 20'. This result showing the volatility of galena in ordinarily pure nitrogen was not a little surprising; but Mi*. Rose had made a perfectly independent experiment, the result of which quite confirmed the volatilit'y of galena in nitrogen.Professor Austen had also ascertained the fact that at 1200" galena may be rapidly distilled in vacuo, and, so far, he had been unable to obtain any evidence in favour of the view that sulphur dioxide pro- motes the volatilisation of lead sulphide more than nitrogen does. He had, however, tried a further experiment. A kind of air thermo- meter was arranged, with a porcelain tube for a bulb, in which a certain amount of galena was placed in an atmosphere of sulphur dioxide. The tube was then heated strongly, and the expansion of the gas carefully measured by means of a moving index of mercury in a horizontal capillary tube.Tho presence of galena produced no abnormal change in the volume of sulphur dioxide such as might be expected to occur if a gaseous compound of sulphur dioxide and galena were formed. It should be remarked, however, that sulphur dioxide alone appears to exhibit contraction about lOOO", and the cause of this fact is being examined; but the presence of galena did not 155 increase the observed condensation. Metallurgists would welcome the proof of the existence of gaseous compounds of lead sulphide ; but although Mr. Hannay had undoubtedly shown that the whole metallurgy of lead should be further investigated, the existence, composition, and nature of the volatile compounds could not, as yet, be considered to be established. Mr. ROSEexhibited a porcelain tube in which 6 grams of galena, contained in a boat between asbestos plugs, had been heated at 1300" for half an houia in a dow current of nitrogen, the temperature being taken by Le Chatelier's optical pprometer.Practically the whole of the galena had b5en volatilised, and, passing through the plugs in both directions, had been condensed as crystals in the cold parts of the tube. He had tried to isolate the supposed compound, PbS,O,, by means of Deville's hot and cold tubes, galena being heated to about 1250" in a stream of sulphur dioxide, but had been unsuccessful, the sublimate on the cold tube consisting entirely of lead sulphide. It was to be remembered that several substances, such as ozone and oxide of silver, which, although more or less unstable at moderate tempera- tures, could exist at a white heat, had been prepared in this way, and the method had appeared to be the most likely one to succeed in effecting the isolation of PbS,O,. The failure was therefore not without significance.Mr. H. C. JENKINSsaid that some experiments had been carried out in the metaJlurgica1 laboratories of the Royal College of Science. It was found that lead sulphide (galena) was easily volatile in a vacuum at a temperature only a few degrees above its melting point. In a current of sulphiir dioxide the rate of volatilisation was, as would be expected, much increased, but a similar current of nitrogen gave even better results than sulphur dioxide. Very careful experiments were made with mixtures of galena and sulphate of lead, but, although some of the products resembled those that Mr.Hannay had described, yet the evidence obtained did not point to the existence of a vola- tile compound PbS,SO,. In some cases only the acting compounds were present ; in others the experiments were performed in an atmo- sphere of sulphur dioxide in the presence of furnace gas. Metallic lead was only seen as a separate product in the latter case, But it was found that pure metallic lead is capable of decomposing sulphur dioxide, forming sulphur and oxide. Experiments were still in progress with a view to obtain quantitative knowledge of the change. The existence of volatile lead c3mpounds would, if proved, offer an easy explanation of the cause of lead fume, but in view of the volatile character OE well known compounds of lead at furnace temperatures, much more experimental evidence khan has yet been afforded is needed to demonstrate the formatim of new compounds. The PRESIDENTsaid, that t.he discussions to which Mr.Hannay’s papers had given rise were of considerable value in calling attention to the many interesting points in the metallurgy of lead which still required investigation. The main question around which the interest of the discussion centred was that relating to the existence of volatile compouiids of lead sulphide. The experiments which he had witnessed certainly favoured the conclusion that sulphur dioxide exercised a specific effect, in volatilising lead sulphide ; but assuming that the evidence that combination took place was satisfactory, he could not regard Mr.Hannay’s observations on the extent to which volatilisation took place as satisfactory determinations of the compo- sition of the volatile compound ; such a compound would probably be dissociable, and, if so, it was not to be expected that the gas and galena would pass over and be collected in exact molecular ratios. The strongest evidence was undoubtedly that derived from passing air into molten galena ; the manner in which galena volatilised and passed away as lead sulphate under such conditions was extra-ordinary, and still more remarkable was the fact that,, as Mr. Hannny stated, just half the lead was obtained in the metallic state. Experi-ments made in his laboratory, under Mr.Hannay’s direction, had given this result, and it was certainly a remarkable coincidence if the result were but accidental. It appeared to him that, although Mr. Hannay could not be held to have established his point, he had called attention to peculiarities in the beliaviour of lead sulphide which were of groat interest to metallurgists, and that he had clearly made out a case for enquiry. Mr. HANNAY,in reply, said that he was glad to find it was now recognised that the simple equations of the text-books did not adequately represent the facts, and that nearly all the furnace reac- tions of lead compounds were very complex. As to the volatility of the sulphide and the formation of a definite compound with sulphur dioxide, this conclusion mas based on the action of air on molten galena, an action which alwap proceeded in the same manner, and was represented by the equation ZPbS + 0, = Pb + PbS*S04,as exactly one-half of the galena is reduced to lend and left in the metallic state, and one-half is volatilised with the sulphur dioxide.Whether this was a definite compound or a mere chance volatility in molecular proportions was a question which might still admit of experimental investigation, and it was to be hoped that some of those who had spoken would carry the work further. As showing that sulphur dioxide when set free in intimate contact with molten galena, does act in a special manner, it might be stated that while nitrogen and hydrogen gases passed at the rate of 1litre in three minutes through the molten sulphide, carried over the galena as 157 vapour at the rate of 3.5 grams per litre of gas passed, air under the same conditions carried over 5.2 grams per litre.Now if the amount carried over by the nitrogen of the air were the same as that carried over by pure nitrogen, there is a large excess ca,rried over by the sulphur dioxide (formed by the combination of the oxygen of the air with the sulphur of the galena), and this excess is present in nearly the proportion indicated by the formula PbS*S02 or PbS202. All the evidence pointed to the fact that when sulphur dioxide was formed in intimate contact with molten galena, every molecule of sulphur dioxide rendered volatile 1 molecule of galena, and subsequently deposited it on cooling.The volatility is so profoundly modified by temperature, that experiments are not comparable unless carried out at the same temperature, a result dificult to obtain, but Mr. Hannay hoped that Professor Roberts-Austen would test the matter, and lay down accurate data for future work, as all statements of temperature had hitherto been only the roughest approximations. “33. “The mineral waters of Cheltenham.” By T. E. Thorpe,D.Sc., F.R,S. This communication contains the results of the analysis of the waters of the following wells:-(A.) (1) Well Place; (2) Christ-church Road. (B.) (1) Lansdowne Well; (2, 3, and 4) Pitville Spas.The determinations, so far as applicable, are compared with the results of analyses by Abel and Rowney, made in 1847, from which it appears that the waters have experienced no sensible altera- tion in composition during the last half century. “34. “The oxidation of tartaric acid in presence of iron.” ByH. J. H. Fenton, M.A. This paper gives an account of the investigation undertaken by the author to explain the cause of a peculiar colour reaction cf tartaric acid observed by him some years ago. Free tartaric acid, or a soluble tartrate, is oxidised by certain agents in presence of a trace of ferrous salt, when, on addition of alkali, a beautiful violet colour is produced. The isolation of the substance which gives rise to this colour was, in the first instance, a matter of considerable difficulty, owing to the unstable nature of the solution, but a method has now been devised whereby it can be obtained in considerable quantities and in a state of purity.It has the appearance of a shining, white, crystalline mass with tt pearly lustre. The crystals are quite permanent in the air, but effloresce over sulphuric acid or when heated. Analyses and molecular weight determinations by different methods show that 158 the siibstance is a dibasic acid of the formula C,M,O,, which crys- tallises with 2H,O. It is very sparingly soluble in cold water, acts as a powerful reducing agent, and gives a violet colour with ferric chloride in presence of alkali, changed to a transient green by acids.On heating with hydrogen iodide, it gives snccinic acid, glycotartaric acid being an intermediate product. The aqueous solution decom- poses slowly at ordinary temperatures, and rapidly on heating, giving carbon dioxide and an aldehydic substance which is under examina- tion. Phenyl hydrazine gii-es two crystalline compounds, one a brilliant silver-white, and the other golden-yellow. The methyl salt is volatile at about 150", and may be sublimed in crystals ; the ammonium, sodium, and barium salts also are easily obtained in the crystalline forni. The acid somewhat resembles dioxytartaric acid in the sparing solubility of its sodium salt, but differs considerably from that acid in other respects. The constitution of the acid will be considered in a future com- munication, but the author intends also to investigate several side issues suggested by this work, such as the detection of peroxide of hydrogen under certain conditions, the preparation of glyoxylic acid, and the oxidation of other substarices in presence of ferrous salts."35. "The supposed relation between the solubility of a gas and the viscosity of its solvent." By T. E. Thorpe, F.R.S.,and T. W. Rodger. In .the Zed. fiirphysik. Chem., 9,171, 1892, appeared a short com-munication by TJ. W. Winkler, in which he attempted to account for the fact that the solubility of a gas in water diminished with rise in temperature. The conclusions which he arrived at may thus be stated :-(1.) For the same gas the percentage diminution in its absorp-tion coefficient for any temperature-interval is proportiollal to the corresponding percentage diminution in the viscosity of the solvent.(2.) For any gas the percentage diminution in its absorption coefficient for the same temperature-interval is proportionnl to the cube root of its molecular weight. These conclusions were based on Tinkler's own observations on the absorption coefficients of hydrogen, oxygen, nitrogen, nitric oxide, and carbonic oxide in water, and on the relative numbers given by Graetz for the viscosity coefficients. The authors, when endeavour- ing to ascertain how far these deductions were affected on employ- ing the values recently obtained by them for the viscosity coefficients of water, have found that, owing to imperfect mathematical treat- 159 ment, Winkler’s conclusions have to be modified.The deductions which the facts appear to warrant are :-(1.) For the same gas the diminution in solubility, and not the percentage diminution, is proportional to the corresponding diminution in viscosity. (2.) For any gas, the factor of proportionality is greater the greater its molecular weight, although the two do not appear to be simply related to one another. The authors also call attention to the fact that since the viscosities of a large number of organic liquids at different temperatures have now been determined, lack of data concerning the solubility of gases in such solvents alone stands in the way of a more complete investi- gation of the interdependence of solubility and viscosity.“36. “The specific character of the fermentative functions of yeastcells.” By Adrian J. Brown The usually accepted view as to the cause of the exhibition of the fermentation functions of yeast cells is, that it is a stamation phe- nomenon brought about by want of free oxygen during the life of the cells in a fermentable liquid; or, more briefly, that it is a phe-nomenon of “life without air.,’ This view was originated by Pasteur, a full account of the experimental results which led him to formulate this theory being given in Chapter VI of his “ Etudes de la Bihre.” In a paper on the influence of oxygen on alcoholic fermentation (J. Chem. Soc., 61, 369), attention was called by the author to the fact that some of the experimental result,s described appeared to be con-tradictory to Pasteur’s theory.Further work on this subject has led him to think that a review of the experiments on which Pasteur’s theory rests, in conjnnction with the results of some of his own, will not be out of place at the present time. Pasteur’s experiments may be divided into two cIasses, one con- taining experiments which appear to have suggested his theory, the other containing experiments undertaken for the purpose of proving its truth. It is not proposed to discuss the experiments in the first class, as, although they demonstrate most importnn t facts regarding the life and growth of yeast, they afford no proof that fermentation is a,consequence of “life without air.,, The attempted proof of this theory lies in those experiments by which Pasteur determines, under varying conditions of agration, the proportion of the weight of the yeast formed to the weight of sugar fermented.This ratio, or proportion, of yeast to sugar is, Pasteur considers, an expression of fermentative power ; and when consider- 160 ing the ratios established by different experiments, he treats them as comparable with each other. By thus comparing fermentative powers of yeast cells under varying conditions of aeration, he arrives at the conclusion that when agration is perfect, fermentative power ceases, and when aGration is reduced, fermentative power increases :the p~oof of Pasteur’s theory, indeed, rests upon this conclusion.As SO much turns on Pasteur’s interpretation of the experimental results by which he determines fermentative power, it is desirable to test it as thoroughly as possible. The ratio of yeast formed to sugar fermented in any experiment is an expression of fermentative power ; but if it is found desirable to cornpure fermentative powers determined from the results of two or more experiments, it becomes necessary to make sure that either the total fermentative power, or some known fraction of it, has been measured in each case, otherwise no true comparison can be made. The ratios determined in Pasteur’s experiments are used as though they represented the total fermentative powers of the yeasts con-cerned; but there is no evidence in support of this, and they may represent unknown fractions of the powers equally as well.In the majority of Pastenr’s experiments the sugar used was completely fermented, and exhibition of fermentative power by the yeast was thus limited by the amount of the sugar originally present in the fermentable liquid ; but there is no evidence that, under these condi- tions, the yeast had exerted all its fermentative power. If the amount of yeast formed during fermentation were. in direct propor- tion to the sugar fermented, t,he ratio of yeast to sugar would remain constant, however much or little sugar were available ; but experi- ments made by the author sham conclusively that such is not the case.The amount of sugar available during fermentation is a factor that has but little influence on yeast increase; there is, in fact, no direct proportion between weight of yeast formed ad sugar fer-mented. In order to show that the total fermentative power of yeast has not been measured in Pasteur’s experiments, a fermenta-tion was carried on under agrobic conditions until the sugar origin- ally present was decomposed. Afterwards, using the principle of overcrowding as a means of preventing reproduction, t,he crowded cells were fed with more sugar. Feeding was carried on at intervals until the yeast had fermented three times the amount of sugar originally present at the beginning of the experiment, but no in- ci-ease in the weight of yeast took place.Thus the fermentative power of the yeast was found to be at least threefold what it would have been if determined in the manner adopted by Pastour. In most of Pasteur’s experiments under aerobic conditions, the ap-parent deficiency in fermentative power of the yeast was doubtless 161 due to the quantity of sugar on which the yeast could exert its power being limited in amount. In two experiments Pasteur estimated fermentatlive power under asrobic conditions, the yeast being in contact with sugar at the ter- mination of the experiment, viz., in his experiments carried on in shallow dishes in order to expose the yeast to the maximum asration possible. Pasteur believed that, under these conditions, the fermen- tative power of yeast was reduced to such a point that practically the yeast was no longer a ferment, but lived the ordinary life of a fungoid growth in air.But these experiments are open tJothe serious objec-tion that, as they were allowed to continue during but a limited time, a time factor is introduced. Pasteur himself maintains t.Eiat time had nothing to do with fermentative power, yet it enters into the question when consideriag these experiments. Moreover, as cane-sn gar was used in these experiments, it must have been inverted before being fermentable. The author finds that inversion proceeds very slowly under the conditions of Pastenr’s experiments. As inversion must precede fermentation, and is a function of the yeast cell apart from that of fermentation (J.O’Sullivan, Trans., 61, 593), Pasteur’s measure of fermentative power in the experiments referred to is an expression of the action of the inversion and fermentation functions of yeast cells in a limited time. Under these circumstances no reliance can be placed in the figures Pasteur gives as representing the true fermentatire power of the yeast. Apart from the fact that Pasteur fails to prove the truth of his theory by comparing fermentative powers, his hypothesis is further weakened by the fact that none of the results of his experiments are contradictory to a hypothesis opposed to his. The agrobic and anaerobic life-history of yeast, as domonstrated by Pasteur, can be accepted without the truth of his hypothesis regarding fermentative being admitted.There is no prim6 facie reason why the fermentation functions of yeast cells should not be exercised independently of the cells’ environment, so far as the presence or absence of free oxygen is concerned ; and nothing in Pasteur’s experiments contradicts this. 37. “ Observations on the influence of temperature on the optical activity of organic liquids.” By Percy Frankland, Ph.D., F.R.S., and John MacGregor, M.A. The authors, after referring to the few isolated observations by Pictet, Perkin, and others, give the results of the polarimetric measurements which they have made at different temperatures between 0” and 35” C. with some of the ethereal salts of active gly- ceric and diacetylglyceric acids. Owing to the comparatively nn - 162 stable nature of the cthereal salts of glyceric acid, cnut8ion has to be exercised, or the effect of decomposition may be mistaken for the influence of temperature.It is shown that these glycerates havo a tendency, especially at higher temperatures, to partially decompose into alcohol and glyceric anhydride, and the latter remaining in solution in the undecomposed ethereal salt and alcohol, causes an increase in levorotatioii. By avoiding this source of error, however, it is shown that the rotation of methylic and ethylic glycerates undergoes very marked increase as the temperature rises, the in- crease being greater in 'the case of the methylic t-lian in that of the ethylic compound. The influence of temperature on the rotation of the diacetylglycerates is considerably greater, and, owing to their stability even at high temperatures, they lend themselves better to observations of this kind than do the glycerates.The results ob-tained with the glycerates and diacetylglycerates have been sum-marised, whilst for comparison there are also recorded the correspond- ing figures calculated from Pictet's determinations made with the tartrates at 20" and 100" C. In each of the three series of homologous compounds the percentage increase in rotation for a given rise in temperature is greatest for the methyl, and then for the ethyl, compound, whilst the higher members of each series exhibit in general successively smaller increments. Reference to the previous paper will show that it is precisely in the first few members of each series also that the addition of CH, causes the greatest increase in rotation, or, in other words, in those cases in which the degree of molecular dissymmetry is most increased by a rise of temperature, the dissymmetry is also most increased by an ad- dition of CH,, and vice versc2.38. "The maximum molecular deviation in the series of the ethereal salts of active diacetylglyceric acid." By Percy Frankland, Ph.D., F.R.S.,and John MacGregor, M.A. The authors have previously shown that in the homologous series of the ethereal salts of active glyceric acid, the rotation is increased by each addition of CH, in passing from methylic glycerate to normal butylic glycerate, whilst higher in the series the further addition of CHz, on the contrary, leads to a diminution in the rotatory power.This culmination of the rotatory power in the butylic glycerate is most strikingly exhibited by calculating what has been termed by Guye the molecular deviatiorh, [6]D, for each of the members of the series, according to the formula 163 in which a is the observed angle of rotation, L the length of the polarimeter tube, M the molecular weight, and d the density. The authors show in the present paper that there is the same phenomenon of a maximum rotation in the series of the ethereal salts of diacetylglyceric acid, and that this maximum is again reached at much the same point in the series, for whilst the rotation rises suc-cessively in passing from methylic to isobutylic diacetylglycerate, the normal heptylic and octylic compounds already exhibit a falling off in the rotation.The curves representing the molecular deviation of the ethereal salts of glyceric and diacetylglyceric acids respectively are in fact found to be roughly parallel, each diacetylglycerate possessing a rotatory power which is in excess of the rotatory power of the corresponding glycerate by a difference which does not undergo much change throughout the series. A particularly interesting feature in the series of diacetylglycerates is the circumstance that in the methyl compound there are two groups of equal mass, and again, in the ethyl compound, two other groups of equal mass attached to the asymmetric carbon atom, but these relations are not attended with any change of sign throughout the series.The authors have also commenced studying the effect of replacing the hydroxylic hydrogen in glyceric acid by higher negative radicles than acetyl, and have found that whilst methylic dipropionyl glycerate is slightly inferior in lzevorotatory power to methylic diacetylglycerate, methylic dibenzoylglycerate is powerfully dextrorotatory. 39. “The preparation of sulphonic derivatives of camphor. By F. Stanley Kipping, Ph.D., D.Sc., and William J. Pope. The method which the authors have previously given (Trans.,. 1893, 548) for preparing the sulphonic chlorides of camphor and of its halogen derivatives, by acting ou the sodium salts of the sulphonic acids with phosphorus pentachloride, is tedious and un- economical.The crude, hygroscopic sodium salts do not crystallise from the impure solutions in whicb they areobtained after sulphona- tion, and during the process of drying they undergo partial decom- position ; the resulting sulphonic chlorides are consequently very impure, and are only isolated with difficnlty, the yield being compara- tively small. Requiring large quantities of the pure sulphonic chlorides in order to study the halogen derivatAves of camphor, which may be obtained from them by the method indicated in a previous note, it seemed desirable, in the first place, to improve the mode of preparatioii. This was accomplished by employing the ammonium salt’s of the 164 sulphonic acids, which, unlike the sodium salts, are anhydrous, crys- tallise comparatively readily, and are easily obtained in a pure condi- tion, even from highly impure solutions.The crude sulphonic chloride8 prepared from these salts contain but little impurity and are very easily isolated, the yield being nearly theoretical ; the sulphonic bromides, which were very difficult to obtain from the crude sodium salts and phosphorus pentabromide, may be readily prepared from the pure ammonium salts. Bromocamphorsulphoic bromide, CloH140Br*S02Br,prepared from ammonium bromocamphorsulphonate, crystallises in large, trans-parent, lustrous octahedra, and is quite different in crystalline form from the corresponding sulphonic chloride ; it has no definite melting point, but decomposes at about 140"with evolution of sulphur di- oxide forming a new dibromocamphor, which will be described later.ChlorocanzplzorsuIphonic bTomide, CloH140C1*S02Br,obtained from the ammonium salt of chlorocamphorsulphonic acid, also forms large, colourless octahedra and undergoes decomposition when heated, giving a halogen derivative, which is being investigated. Camnphorsulphonic bromide, CI0Hl50*SO3Br,was prepared from the feebly active ammonium camphorsulphonic acid, as it was interest-ing to compare its behaviour with that o€ the inactive sulphonic chloride (Trans., Eoc. cit.) ; the crude product seems to consist of a mixture of optically active and inactive substances, as in the case of the sulphonic chloride, but the existence of a definite racemic modi- fication has not yet been establiahed. 40."Dextro-rotatory camphorsulphonic chloride." By F. StanleyKipping, Ph.D., D.Sc., and William J. Pope. Dextro-rotatory camphorsulphonic chloride has been previously described, but, owing to the great difficulty experienced in separating even a few grams of this substance from the inactive modification, it was not possible to make as complete a study of its derivatives as ap- peared desirable. It has now been ascertained that this optically active sulphonic chloride may be prepared in almost any quantity from the ammonium salt of bromocamphorsulphonic acid ; when the latter is reduced with zinc dust and ammonia, it is rapidly converted into the ammonium salt oE dextro-rotatory camphorsulphonic acid, from which the sulpbonic chloride may be obtained by acting with phosphorus pentachloride (see preceding note).The product crystallises in colourless, transparent tetrahedra melting at 137.5",and is shown to be identical with the optically active sulphonic chloride already de- scribed, not only by these properties but also by crystallographical measurements. Its production in this way not only makes it possible to push the investigation of its derivatives further, but is also of 165 theoretical interest, inasmuch as it proves that on sulphonating eit,her camphor or bromocamphor the sulphonic gi’oup becomes united with one and the same carbon atom, unless the highly improbable assump- tion be made that camphor contains two similarly orientated groups from which hydrogen may be displaced. Dextro- rotatory camphomulphonic bromide, CIoH,,O.SO,Br, has also been prepared in a similar manner; it crystallises in well-defined transparent octahedra, isomorphous with the crystals of the active sulphonic chloride, and resembles the latter very closely in ordinary properties.The halogen derivatives obtained by heating these two active com- pounds will be described later. 41. “On the combination of chlorine with carbon monoxide under the influence of light.” (Preliminary Notice.) By Gibson Dyson, Ph.D., and A. Harden, Ph.D., M.Sc. Equal volumes of chlorine and carbon monoxide were mixed by diffusion in an apparatus consisting of two cylindrical bulbs with water jackets, connected by a capillary tube with a gauge containing sulphuric acid, the space abore the acid being filled with carbonyl chloride, so that only the two gases and the product of their combina- tion were present. The action of light upon the mixed gases was studied by burning a measured piece of magnesium ribbon at a constant rato and at a measured distance in front of one of the bulbs, and observing the movement of the acid in the gauge. As soon as equilibrium was restored, a second piece of magnesium was burned and the gauge again observed.It may be assumed that in these experiments rise of the acid in the capillary tube of the gauge is proportional to the amount of combination produced.The experiments hitherto carried out show that when a mixture of equal volumes of the two gases, half saturated with moisture, is exposed to the action of the light from burning magnesium ribbon, there is a well marked period of photochemical induction. This is illustrated by the following numbers, taken from one of oar numerous experiments, which give the rise of the acid in the gauge in scale divisions caused by successive equal amounts .of light. Scale Divisions. 1 .................... 1 2 .................... 8.5 3 .................... 18 4 .................... 20 5 ................. 24 Constant. The action of light upon exactly equivalent volumes of the two gases under various conditions is now being investigated, and experi- ments are being made on the combination of chlorine with other gases.We hope at no distant date to be able to lay the results of these experiments before the Society. 42. “Solution and pseudo-solution.” Part 11. By S. E. Linder and Harold Picton. This is a continuation of previous work by one of the authors on arsenious sulphide solutions. The previous series of arsenious sulph- icie solutions has been extended, a solution having been prepared by the action of sulphuretted hydrogen on more dilute arsenious acid, which is filterable through a porous pot in addition to being diffusible. The following different solutions have now been prepared : As,& (a), with aggregates visible under microscope ; As2Sj(p), invisible, but not diffusible ; As2S3(y), diffusible, but non-filterable ; As,S, (a), diffusible and filterable, but showing a polarised beam in Tyndall’s experiment.The following experiments have been made with the “higher grade ” solutions (y and 8). 1. Coagulative Power.-Metallic salts are found to arrange them- selves in sharply-divided groups as regards their power of coagulating solutions of arsenious sulphide. The group into which a metallic salt will fall depends on the valency of the metal. The trivalent metals have the highest coagulative power, divalcnt metals about one-tenth, and monovalent metals less than one five-hundredth of this power. These differences are also shown by the same metal (e.g., iron) when exhibiting varying valencies.The negative group also causes varia- tion, and it is noteworthy that the coagulative power of the halogens is very similar, and so, also, is that of the arsenic and phosphoric acid radicals. The effect of successive additions of salts of the same group is a corresponding increase in the amount of coagulation, whilst that of salts of different groups is to hinder coagulation, the latter effect attaining a maximum when a certain quantity of the first salt has been added. Thus if potassium chloride is first added and then strontium chloride, the addition of more potassium chloride increases up to a certain maximum the amount of strontium chloride required to complete the coagulation. Certain applications of these results have suggested themselves.Thus, coagulative power might possibly be applied to check the valency of a metal in different compounds. Again, it is noteworthy that there is an unusual difference between the coagulative powers of free arsenic and phosphoric acids and their salts. It is also sugges- tive that, free stilpliurous acid differs widely in coagulativc power from sulphuric acid, while sodium sulphite differs only comparatively slightly from sodium sulphate. PossiblF relative coaguulative powers may have an interesting bearing on questions of constitutional rela- tionship. 2. Relative Density.-This varies quite regularly with dilution, t,he relation between relative density and dilution being represented hg a straight line.This agrees with the results obtained with fairly dilute sugar solutions (B per cent.), while strong sugar solutions (18 per cent.) and dilute salt solutions (0.2 per cent.) show a smaller diminution of relative density indicative of the formation of hydrates. 3. Volume-change on Coagulation.-It is found that when coagu- lation is conducted in a very sensitive apparatus, consisting of a flask of about 350 C.C. capacity fitted with a ground stopper carrying a c.apillary tube, there is absolutely no volume crlange on coagulation. Calcium chloride was used as the coagulant, and to eliniinate the con-traction produced hy it, equal quantities of the same solution were used inclosed in tliin glass bulbs. Two determinations with distilled water gave a volume change of O.OL77 and 0.0174 C.C.With the sulphide solution the contraction was 0.0175 C.C. 4. Snrface-tension.-As determined by the rise of the solution in a capillary tube, the surface-lension of water is unaffected by the presence of dissolved arseniocs sulphide. Cane-sugar, on the other hand, causes a small but distinct increase of surface-tension. 5. Osmotic Pressure.-The results of osmotic pressure measure-ments are very variable, but the authors think themr;elves justified in concluding that an osmotic pressure exists. Thus, a 4 per cent. solu-tion has yielded a pressure of 17 mm. of water. No comparative dcterminations seem reliable, but a distinct pressure is always ob-served with diffusible solutions, but this is not observed with filterable substances.The smallness of the pressure would suggest exceedingly great molecular complexity. Among new solutions examined may be mentioned the uranium and iron dextrosates, kindly placed at our disposal by Mr. Chapman. These scatter light and are non-filterable, but the iron compound, in presence of animoiiin and ammonium chloride, does not scatter light, :~ndis filterable. The complicated tungstate, 60WO,.3P,O,.VzC5.V0?.1_8Rf10 + 150HT,0,does not scatter light and is filterable. 43. "Solution and pseudo-solution." Part 111. By Harold Picton and S. E. Linder. Tho authors describe fiirther work on the electrical repulsion of certain solutions, The results are fully tabulated in the paper.Itt may be well to recall that iE an attempt is made to pass a current through arsenious sulphide solution, the sulphide is repelled as a whole from the negative electrode, and also to a certain extent from the positive electrode, without appreciable elec troljsis. A large num- ber of solutions showing characteristic repulsions have now been investigated. Thus aniline blue (of various kinds) is repelled from the negative electrode, M-agdala red and methyl violet from the positive, sulphur and iodine are repelled from the negative electrode. It seeins impossible to obtain repulsion in an absolutely non-con- ducting medium. For instance, iodine in carbon disulphide is not repelled. Again, on doubling the length of an arsenious sulphidc column, the rate of repulsion is approximately halved.Indigo in water is repelled from the negative, in naphtha it is not repelled. In general, when solutions exhibiting opposite repulsions are mixed, complete coagulation of the dissolved substance occurs. Under cer-tain conditions of dilution the coagulation may be avoided, but in this case the mixture descends to a lower “grade” of solution. The aggregates of this I‘ lower grade ” solution are repelled as a whole from one electrode. Further, in two suitable cases the experiment was made of adding R new solvent (alcohol). The aggregates of the “lower grade ’’ mixture were then found to dissociate and to be repelled individually from their characteristic electrodes. These facts are all illustrated by t’he cases of aniline blue mixed with Magdala red, and aniline blue mixed with methyl violet.Aqueous solutions of aniline blue with weak alcoholic Magdala red coagulate ; aqueous aniline blue with aqueous Magdala red yield a ‘‘ lower grade ’’ solu-tion, which is repelled from the negative electrode unless the Magdaln red is much in excess. On dissolving the coagulation of (1)in strong alcohol, a higher grade solution is obtained, in which the aniline blue and Magdala red are repelled separately. If a degraded solution of two oppositely repelled substances is taken, e.g., an aqueous solution of aniline blue and methyl violet, on adding a third snbstaiice (e.g., ferric hydrate) the combined aggre-gates in the solution are carried down as wholes, and the result is that all three substances separate out.On the other hand, if we take an alcoholic and dissociated solution of aniline blue and methyl violet, on adding ferric hydrate (positive) only the aniline blue (negative) is carried down, while the methyl violet (positlive) is left in solution. This affords an additional test of “ degradation ’’ where the optical test fails. Thus aniline blue in alcohol with ferric hydr- ate in alcohol do not combine, for on coaguls,ting with potassinm sulphate only the ferric hydrate is carried down. The aqueous solu-tions do combine, as is shown by the Dotasaium sulphate causing bot,h to separate. Filtration also af’fords a test of combination. Thus 169 arsenious sulphide (positive or negative) does not coagulate with aniline blue (negative), but combination occurs, as on filtering no aniline blue passes through the porous pot.APPOINTMENT OF ASSISTANT SECRETARY AND LIBRARIAN. The Council of the Chemical Society having decided to appoint a.n Assistant Secretary and Librarian, applications are now invited for this ofhe. They should be sent to the Secretaries, at Burlington House, not later than July 25th. The Assistant Secretary will be provided with assistance in the Library, and will be required to devote his whole time to the duties of the office. The salary will be $150 per annum, rising to $200. Candidates will be expected to produce evidence of having received a chemical training. RARBISON AND SONC3,PBINTEB.S IN OBDINAEY TO HER ;UAJESTY,ST.XAPTJX’B LAPIE
ISSN:0369-8718
DOI:10.1039/PL8941000151
出版商:RSC
年代:1894
数据来源: RSC
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