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Proceedings of the Chemical Society, Vol. 14, No. 188 |
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Proceedings of the Chemical Society, London,
Volume 14,
Issue 188,
1898,
Page 21-32
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摘要:
Issued 10/2/1898. PROCEEDINGS OF THE CHEMICAL SOCIETY. EDITED BY THE 8ECRETARIEX. ~~~ No. 188. Session 1897-8. February 3rd, 1898. Professor Dewar, F.R.S., President, in the Chair. Certificates were read for the first time in favour of Messrs. Charles Baskerville, North Carolina University, Chapel Hill, North Carolina ; Alfred Campion, 637, Alexandra Parade, Dennistown, Glasgow ;Robert Martin Caven, University College, Nottingham ; F. Hudson-Cox, 67, Surrey Street, Sheffield ; John Arnold Fleming, Britannia Pottery, Glasgow ; Harry Pearson Hodgson, Caldew Bank, Cummersdale, Carlisle; Edwin Charles Jee, 45, Pepys Road, New Cross, S.E.; Edward Jones, Vine Cottage, Tudor Road, Kingston-on-Thames ; Walter Ratcliffe, 21, Mawdsley Street, Bolton ; Henry Somerville 33, Vincent Square, S.W.; Harry St. John, Thornfield, Sunderland. Of the following papers those marked * were read :-*8. “The volumetric estimation of sodium,” By H. J. H. Fenton, M.A. Dihydroxytartaric acid, in presence of dilute sulphuric acid, is readily oxidised by potassium permanganate at the ordinary tempera- ture, the reaction affording a very convenient method for the estima- tion of the acid or its salts. A method has been devised for the quantitative estimation of sodium based upon this relation and upon the sparing solubility of sodium dihydroxytartrate. The solubility of the sodium salt at 0’is shown to be extremely small, and in presence of excess of a dihydroxytartrate is practically negligible. The substance to be examined, in concentrated neutral solution, is mixed with excess of potassium dihydroxytartrate and the mixture is kept at 0’ for half an hoiir. The precipitated sodium salt is washed with a little ice-cold water, dissolved in excess of dilute sulphuric acid and titrated with potassium permanganate.The results obtained with sodium sulphate, chloride, nitrate, acetate, and with rochelle salt, are accurate within 0.3per cent. The presence of magnesium does not interfere with the accuracy of the results, but ammonium salts, if present in excess, lead to low results. Full details for working the process are given in the paper. The potassium and ammonium salts of dihydroxytartaric acid have been prepared and examined, and, together with other derivatives of the acid, will be described in a future communication. DISCUSSION.Mr. HEHNERsaid that analysts would welcome the method. It was remarkable that sodium, the most widely distributed element, had hitherto been without a direct method of quantitative estimation. He would suggest that the process should be conducted gravimetrically. Mr. NEWLANDSmentioned that he had at one time been accustomed to determine sodium as acid oxalate with approximate accuracy by titration either before or after incineration. Dr. LAWSONasked how Mr. Fenton's method for the production of dioxytartaric acid compared, as regards yield, with that usually em- ployed. The sodium salt was of technical importance in the prepara- tion of a valuable dye-stuff, and it would be of interest to know whether the results were comparable with those obtained by decom- posing nitrotartaric acid.Mr. FENTON,in reply, said that he had suggested in the paper that the process might be conducted gravimetrically, but he considered that the volumetric method would find most favour. He had experimented with other sparingly soluble sodium salts, but did not think that any could nearly compare with the dihydroxytartrate as regards in-solubility. In reply to Dr. Lawson, he said that the process possessed many advantages as compared with the usual method of preparing the sodium salt from nitrotnrt'aric acid. "9. ('The atomic weight of boron." By F. P. Armitage. The determination of the water of crystallisation was the method used.The values for the ratio Na,B,07 : H,O obtained by previous workers are not sufficiently concordant to allow of the values for the atomic weight of boron, calculated from them, being regarded as very trustworthy. The discrepancies are probably to be traced to the slight efflorescence which occurs during the preliminary drying of the crystals of borax. A new method of drying was consequently applied, the borax being washed with alcohol and ether successively, and the ether expelled by exposure for 6 hours in a vacuum. A given weight 23 of the dry crystals was dehydrated in a stream of air, the final traces of water being expelled by fusion over the Bunsen burner and not over the blowpipe.In a series of six experiments, the greatest difference in the per- centage value for the water of crystallisation was 0*41S, and the mean atomic weight of the element as calculated from these values 10.959, a number differing by 0.006 from that recently obtained by Ramsay and Aston in their experiments on the distillation of sodium diborate with hydrochloric acid and methyl alcohol. Certain results are also given in which the method of titration (cf. Rimbach, Ber,, 1893, 26, 164) is applied with a view of ascertaining the possible degree of its accuracy. Thus, a given weight of fused borax was dissolved in water and titrated with dilute sulphu ric acid, the strength of which had been determine1 (i) by titration with solution of pure soda of known strength, (ii) as barium sulphate.The value 10.928 was obtained for the atomic weight of boron as :L mean of two experiments performed by this method. DISCUSSION. Mr. VELEYsaid that methods of determination of atomic weights based upon the elimination of water from a crystalline salt pre- sented the difficulties, firstly, of the mechanical inclusion of water within the walls of the crystals, however fine, and, secondly, of the possible efflorescence and deliquescence of such salts, These difficulties, as also that of the intumescence of the anhydrous salt, when heated with the blowpipe, induced Ramsay and Aston to reject this method. It appeared that the author had overcome these difficulties to a great extent by removing the adherent water by washing with absolute alcohol and subsequentIy with ether, which was pumped off, as also by heating the anhydrous salt only at a temperature obtained by the Bunsen burner, and not at that of tha blowpipe, when loss occurred either on account of the volatilisation or the decomposition of the borax.The experiments of the author also showed that the method of determining the atomic weight, proposed by Rimbach, though not of the degree of exactitude necessaty for such determinations, was probably more accurate for the purpose of acidimetry than that of sodium carbonate, which was not readily obtained of the composition required by its molecular formula. Mr. GBOVESasked whether the volatilisation observed when the crucible was heated in the blowpipe flame might not be due to the action of water vapour and carbonic anhydride which would diffuse through the perforated cover.Dr. SCOTTwas astonished that any one now should attempt to determine atomic weights through calculations of the amount of water of crystallisation contained in hydrated salts. The experiments of J. W. Mallet on ammonia alum and of many other experimenters had shown how unsatisfactory such determinations must always be. It was evident that as such salts produced a determinate vapour pressure of water depending on the temperature, if the air in which they were dried contained less than that amount the salt must lose water during its drying. The PRES~ENTconsidered it superfluous to record weighings to six places and the atomic weight to three places of decimals, having re- gard to the method adopted.With reference to the process employed by the author in drying the borax, he failed to understand why, if borax is an efflorescent salt, it loses no water of hydration when washed with absolute alcohol. He suggested that in investigating this point the influence of time should be taken into account. Mr. ARMITAGE,in reply, said that he had not examined the subliniate formed on the lid of the crucible when ignited with the blowpipe, as his object was to show merely that a loss of weight would occur if this method is adopted. The standard of atomic weight taken was oxygen =16. The time occupied for each washing by absolute alcohol was 3-4 minutes.“10. “Rate of escape of ammonia from aqueous solution.” By E. P. Perman, D,Sc. If a current of air is drawn through a dilute aqueous solution of ammonia at a uniform rate, the amount of ammonia q in solution when a volume Pof air has passed through the solution, is accurately represented by the equation log q =a -bV, a and b being constants. The volume of air was measured by a meter. The equation does not express the results given by a concentrated solution; the solution used in most of the experiments contained 70 grams of ammonia per litre. A number of experiments, conducted at different temperatures, prove that the logarithmic formula holds good between 0’ and 46’; it was also found to hold good when the pressure was varied.The value of b is a measure of the rate of escape of the gas from the solution under any specified conditions ;such values were obtained at various temperatures, and a simple connection was found between b and temperature to, vix., log b=u+pt, u and p being constants. Combining the two logarithmic equations, log q=u--y, if log y=a+log V+@, From this expression the amount of ammonia left in a solution aEter a certain volume of air has been drawn through it can be at once calculated, provided that, at the beginning of the aspiration, the strength of the solution was not much greater than that mentioned above. DISCUSSION. The PRESIDENTremarked that the subject investigated by the author was a very complicated one.He thought that the variations in the tension of the ammonia solution used in the experiments should be determined, as a valuable addition to the paper. It was probable that the results would be expressed by the equation-log p=A-B/T-where A and B are constants and T is the absolute temperature, which was applicable to many similar cases. Dr. PERMAN, reply to a question by Mr. Groves, stated that in the conditions of volatilisation of ammonia from the solution had been varied by using flasks of different capacities and tubes of different diameters. In reply to Dr. Wilderman, he said that he considered that his results confirmed Henry’s law for ammonia in dilute solution. In reply to the President, the author said he had found approximately the vapour-pressure of the ammonia solution used in most of the experi- ments at a temperature of 20’ ;it was about 70 mm.although he had not found the vapour-pressure of solutions of different strengths, but intended to do so. He regarded the method of expressing the results given in his paper as the most convenient for the present, though as yet it was only empirical, 11. On the dissociation of potassium platinichloride in dilute solution : and the production of platinum monochloride. ” By E. Sonstadt. A solution of potassium platinichloride in 1000 parts of water undergoes no sensible change on heating for an hour or two. But a solution in 10,000 parts of water becomes turbid almost immediately on heating, and the turbidity increases until, after some hours, the liquid becomes nearly opaque.On continuing the heating for some days, water being added from time to time to maintain the bulk, a sediment forms and the liquid partially clears, By increasing the quantity of water during the heating, the clearance is facilitated. The reactions that take place are, first,t,he dissociation of the potassium platinichloride ; (1) K2PtC1, =2KC1+ PtCl,, and then the decomposition of the platinic chloride, with formation of platinum monochloride (PtC1 or Pt,Cl,) hydrochloric acid, and hydro- gen peroxide, thus : (2) BPtC1, + 6H,O =2PtC1+ 6HC1+ 3H20,. The yellow, non-crystalline precipitate of hydrated platinum mono-chloride is difficult to collect, for it passes through the filter until the pores are clogged, and then the filtration is exceedingly slow.The precipitate should not be dried on the filter, but washed off, as far as possible, into a dish, and the water evaporated. When dried on the water bath, the salt is brown ;it still retains water, the last traces of which can scarcely be expelled before incipient decomposition begins ; the anhydrous salt is black, or nearly so. The clear filtrate, when concentrated, is strongly acid, and on drying and dissolving the residue in a little water, potassium chloride may be crystallised out. There is also a small proportion of potassium platini- chloride, which may be either a portion of the original salt that has escaped decomposition, or may have been formed by a reverse action due to solution of the monochloride in the hydrochloric acid set free as described, in presence of hydrogen peroxide and air.The hydrated salt, when treated on the water bath with strong soda solution, turns brown, and dissolves to a slight extent. But the brown residue is only partially dehydrated, and recovers its original colour after washing and exposure. The soda solution deposits the unchanged salt on dilution and long exposure to the air. It dissolves readily in hydrochloric acid; slightly in hot dilute sulphuric acid, apparently without decomposition ;in moderately dilute nitric acid, used in large proportion, it dissolves to a deep brown liquid, which, evaporated to dryness on the water bath until no acid odour is perceptible, leaves a dark brown residue, This dissolves in hot water to a clear, dark brown liquid, which, on further heating, suddenly deposits the whole of the original salt, less any impurities present, which remain in the solution.The precipitate, when collected on a filter, is deeper coloured than before, being of an orange tint. The filtrate is free from platinum ;but on continued washing with water, the salt dissolves slightly, and the filtered liquid becomes clouded. Advantage was taken of this process of purification to obtain the monochloride for analysis. An attempt to analyse about 0.1 gram of the salt partially failed, owing to the presence of impurities taken up from the enormous proportion of distilled water used in its preparation.The monochloride, purified as described, was washed into a dish, and after drying on the water bath, was transferred to a small porcelain crucible. The salt weighed 0.2575 gram. The crucible was cautiously heated, with frequent application of the cold lid. Traces of nitric acid came off as well as water, When moisture ceased to be given off, the salt weighed 0.2315 gram. It was then more strongly heated, when chlorine came off and a final trace of water. The heat was then raised until the decomposition was complete. The platinum obtained weighed 0.1945 gram, which corresponds to 0.229 YtCl, a result which may be considered fairly satisfactory. It might be supposed that platinic chloride itself, instead of dissociated from potassium chloride as in the described process, would be preferable, when it is desired to obtain platinum monochloride.But the presence of free acid in the best-dried specimens of platinic chloride renders it unfit for the purpose. A specially dried specimen of platinic chloride dissolved in 10,000 parts of water gave a barely perceptible reaction, With 15,000 parts of water, after heating for some hours, the liquid became turbid, and gave a slight deposit, but not equivalent to that obtainable from a corresponding solution of potassium platinichloride. If, however, a solution of platinic chloride be evaporated on the water bath with nitric acid, the residue dissolved in water, and the solution evaporated again two or three times, the platinic chloride is not appreciably decomposed, but retains a little nitric acid instead of the hydrochloric acid with which it is otherwise associated.A solution of platinic chloride thus prepared, heated in 5,000 parts of water, gives a distinct turbidity, but the reaction is more nearly complete with double that proportion of water. The precipitate differs slightly in its properties from that obtained from the potassium salt; it is of a deeper tint, and is but slightly soluble in nitric acid. When treated with nitric acid and the solution evaporated over the undissolved portion, a weak solution only is obtained on adding water, which, on concentrating, deposits the salt, but not instantaneously. After evaporating the aqueous solution, the hydrate of platinum mono- chloride is insoluble in water, except, as in the former case, on con- tinued washing.A specimen of the hydrate thus obtained weighed after drying on the water-bath, 0.1700 gram; when anhydrous, it weighed 0.1549 gram, and after expulsion of the chlorine by ignition 0.1316 gram of platinum remained. Theory requires from this quantity of platinum 0.1552 gram PtC1. The potassium platinichloride used in the experiments had been several times recrystallised, and was perfectly free from acid. The yield of platinum monochloride was about five-eighths of that theoretically obtainable. The author has math. some experiments with the view of directly proving the presence oi hydrogen peroxide in the liquid, though, con- sidering the conditions of dilution and temperature, the quantity present at any time must be exceedingly suall-the total amount pro- duced according to the equation, assuming the reaction to be complete, being in the proportion of from 1: 100,000 to I: "10,000 to the liquid present.Id a solution that had been heated for five days, the author, using the chromic acid and ether test, obtained a faint colora- tion, hardly visible except to an observer of great sensitiveness. The author then prepared a solution in about 15,000 parts of water of some very pure crystals of potassium platinichloride (a previous trial with a salt of only ordinary purity having failed), and heated the solution for several hours at a temperature slightly below 709 There was only a slight turbidity, for the temperature was too low for good 28 progress.On testing the solution the next day, a faint, bluish tint in the ether was perceptible. That hydrochloric acid is a product of the reaction was proved as follows. A hot, strong solution of potassium platinichloride was poured into a large quantity of a nearly saturated solution of pure potassium chloride. The pre- cipitated platinichloride was collected, well washed with water, and after- wards with alcohol, and dried on the water bath. A solution of about one part of this salt to 10,000 of water was heated for five days, the precipitate allowed to settle, and filtered off. A portion of the solution was concentrated in an open dish to about one-fifth of its bulk, and was then distilled.Silver nitrate added to the distillate gave a precipitate of silver chloride insoluble in nitric acid. 12. "Effect of the mono-,di-, and tri-chloracetyl groups on the rotatory power of methylic and ethylic glycerates and tartrates.'' By Percy Frankland, F.R.S., and Thomas Stewart Patterson, Ph.D. With a view of ascertaining the rotatory effect of the halogens when attached at a point in the molecule remote from the asymmetric carbon- atom, the authors have introduced the mono-, di-, and tri-chloracetyl groups into the methylic and ethylic tartrates and glycerates. This was effected by acting in each case with the acid chloride on the ethereal tartrate and glycerate respectively. The acid chlorides were in all cases prepared by heating the halogen-substituted acetic acid with phosphoric anhydride in m current of hydrochloric acid.Two acidyl groups were in all cases introduced, excepting in that of trichlor- acetyl, of which only one equivalent could be made to substitute in methylic and ethylic tartrates, whilst two equivalents reacted with the corresponding glycerat es. The rotations were in all cases determined at several different temperatures so as to ascertain the influence of the latter. The results are summarised in the following table :-[.]pa [.yo Methylic glycerate ........................ -4-80" -8'31"* (calculated). ,, diacetylglycerate ............... -12.04 -19'24* (calculated). [43-44". ,, di-monochloracetylglycerate..-12.91 -17'99 b.p. 197"(15mm.);m.p. ,, di-dichloracetylglycerate...... -13'96 -17-18 b. p. 207" (20 mm.). ,, di-trichloracetylglycerate ... -14-20 -15'30 b. p. 199-200° (15 mni.). Ethylic glycerata ........................... -9.18 -12-55" (calculated). ,, diacetylglycerate............... -16'31 -23.09" (calculated). ,, di-monochloracetylglycerate... -16'80 -22.08 b. p. 198" (15 mm.). ,, di-dichloracetylglycerate ...... -18'20 -21'10 b. p. 203" (15 mm.). ,, di-trichloracetylglycerate ...... -18.70 -18'40 b. p. 202" (15 mm.). * These values for [a],at 100" for methylic and ethylic glycerates and diacetyl- glycerates have been calculated from the data given in a paper by P. Frankland and Madregor (Trans., 1894, 65, 768). 29 [a12,up [q,ooP Methylic tartrate ...........................+2'14" +5'99" m. p. 48".* ,, diacetyltartrate................. --m. p. 103. ,, di-monochloracetyltartrate ... -0.62 +2.57 h.p. 217" (18 mm.);m. p. 55. ,, di-dichloracetyltartrate ...... 411.9 +10'9 b.p. 220-221" (15mm.) ;m.1'. ,, mono-trichloracetyltartrate.. . +8.4 -t10.15 m.p. 79-80". [64-65". Ethylic tartrate .............................. + 7-66 +13'29 ,, diacetyltartrate .................. -t -m. p. 66.5". ,, di-monochloracetyltartrate $... +7*67 +11'81 b. p. 217" (15mm.) ;1n.p. 27-. ,, di-dichloracetyltartrate......... 4-16-3 +17*08 b. p. 225" (15 mm.).), inono-trichloracetyltartrate... +15*5 +17*6 b. p. 185" (16 mm.). Methylic' and ethylic di-monochlorncetylt artrates have also been pre- pared by Freundler (Bull.SOG. chim., 1895, [3], 13, 1055-1063), who only obtained them as liquids with the following rotatory powers :-1:" a[Methylic di-monochloracetyl tartrate = + 3.5' [a]$"= + 9.40"Ethylic 9, 9, In consequence of this discrepancy between Freundler's results and those of the authors, these two compounds have been prepared again (see next abstract), with the result that the authors' figures have been confirmed, 13. ''The rotation of ethylic and methylic di-monochloracetyl- tartrates." By Percy Frankland, F.R.S.,and Andrew Turn-bull, Ph.D. The ethylic compound has been again twice prepared by the authors, using diff went proportions of monochloracetylchloride and ethylic tartrate :-First preparation, [a]y= + 7.90'.Second ,, [ + 7.76'. The substance subsequently crystallised (m. p. 27'), after which the rotation [a]%*= + 7.61' was found. The methylic compound was also prepared, and again gave the m. p. 55"; the rotation was -0.68'. Thus the results obtained with both compounds by one of the authors (see previous abstract) were confirmed, whilst additional evidence of their accuracy was afforded by the ethylic compound being obtained in the crystalline state. Ethylic mono-monochloracetyltartrate in a state approaching purity was also prepared, and it was found to possess a considerably higher dextrorotation than the corresponding di-acidyl compound, thus [u]"r= + 11-44'. * [a];5' = -15.1" (in absolute alcoholic solution)..F a. = + 5" (t=25, 2~1).::See next abstract. 30 It is, therefore, inferred that the higher figures obtained by Freundler may have been due to the presence of monacidyl compounds, and this is borne out by the lower densities and boiling points which he records. ADDITIONS TO THE LIBRARY. I. By Purchase. Boyle. Some Considerations Touching the Usefulness of Experi-mental Natural1 Philosophy. First Part : On its usefulness in reference to the minde of man. Pp. 127. Second Part : Of its usefulness to Physik. Pp. 417. Oxford 1663, Campredon, L. Guide pratique du Chimiste M6tallurgiste et de I’Essayeur. Pp. iv + 808. Paris 1898. Du Clos. Observationes super aquis mineralibus Galliae. Leiden 1685. One volume with :-Lister, Martin.Thermarum ac Fontium Anglis. Leiden 1686. Nietzki, Rudolf. Chemie der Organischen Farbstoff e. Dritte ver- mehrte Auflage. Pp. x + 343. Berlin 1897. 11. Donations. Bolas, Thomas. Glass Blowing and Working, for Amateurs, Expe- rimentalists and Technicians. Pp. 212. London 1898. From the Author. Patents for Inventions, Abridgments of Specifications. Class I. Acids, Alkalies, Oxides, and Salts. Inorganic. Periods 1884-88. London 1896. From the Patent Office. Royal Society, The Record of the. No. 1. 1897. Pp. vi+224. London 1897. From the Royal Society. Royal Society, Yearbook of the, 1896-9’7. No. 1. London 1897. From the Royal Society. Pamphlets. Don, J. R. The Genesis of certain Auriferous Lodes. Pp. 105. Read before the American Institute of Mining Engineers.February, 1897. From the Author. Headden, W. P. Some Products found in the Hearth of an old Furnaceupon the dismantling of the Trethellan TinWorks, Truro, Corn-wall. (Read before the Colorado Scientific Society, November, 1897). From the Author. 31 Mallet, J. W. On the Solubility of Ammonia in Water at Tempera-tures below 0°C. _I_ Note on a somewhat remarkable case of the rapid Polymerisation of Chloral. (Reprinted from the American, Chemical Journal, vol. xix. 1897). From the Author. Manch, R. Ueber die Loslichkeit von Alkaloiden, Glykosiden und Bitterstoffen in concentrieter wassriger Chloralhydratlosung und die Verwerthung des Chloralhydrats in der toxikologischen Analyse. Pp. 26. Strassburg 1897.From the Author, Schaer, 1897. E. Arzneipflanzen als Fischgifte. Pp. 65. Strassburg. From the Author, Spegers, C. L. Molecular Weights of some Carbon Compounds in Solution. (Reprinted from the Jozcmccl of Physical Chemistry, December, 1897). From the Author. Symons, Brenton. A Geological Sketch of the Coolgardie Gold- fields. Pp. 49. London, 1896. From the Author, Wood ward, H. B.,F.R.S. h Memoir of Thomas Beesley, J.P.,F.C.S. Warwick 1897. From the Author. Zen&ti, Paul. Mikrokrys tallinisc he Nieder schlage der Pi krin saure mit Alkaloiden. Strassburg 1897. From the Author. At the next meeting, on February 17th, there will be a ballot for the election of Fellows, and the following papers will be read. ‘(Observations on the influence of the silent discharge on stmob-pheric air.” By W. A. Shenstone and W. T. Evans. ‘‘Some lecture experiments.” By J. Tudor Cundall, 16.5~. “On the condensation of formaldehyde with ethylic rnalonate : am; on cis- and trans-tetramethylenedicnrboxylicacid.” By E. Hawortl and Vr’. H. Perkin, junr., F.R.S. RICHARD CLAY AND SONS, LIMITED, LONDON AND BUNGAY.
ISSN:0369-8718
DOI:10.1039/PL8981400021
出版商:RSC
年代:1898
数据来源: RSC
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