摘要:

JANUARY 1908. Vol. XXXIII. No. 382. THE ANALYST. PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS AND OTHER ANALYTICAL CHEMISTS. THE monthly ordinary meeting of the Society was held on Wednesday evening, December 4 in the Chemical Society’s Rooms Burlington House. The President, Mr. E. J . Bevan occupied the chair. The minutes of the statutory meeting and of the ordinary meeting held on November 6 were read and confirmed. Certificates of proposal for election to membership in favour of Messrs. Charles Edward Cassal F.I.C. Town Hall Kensington W. Public Analyst ; James Kear Colwell F.I.C. Finsbury Town Hall E.C. Public Analyst ; Frankland Dent M.Sc. (Victoria and Leeds) Ph.D. (Munich) F.I.C. Singapore Government Analyst, Straits Settlements ; Reginald Doresa F.I.C. 2 Broadway Westminster S.W.chief assistant to Mr. R. H. H. Stanger ; Francis Salsbury Earp M.A. Ph.D. (Giessen), 35 Porter Street Kalgoorlie Australia Public Analyst ; and Rudolf Lessing 317, High Holborn W.C. analytical and consulting chemist were read for the first time ; and certificates in favour of Messrs. F. H. Duprd P. V. Duprd J. C. Kirkaldy and E. H. Merritt B.Sc. were read for the second time. Mr. C. REVIS was elected a member of the Society. Messrs. W. P. SKERTCHLY and L. MYDDELTON NASH were appointed Auditors of The PRESIDENT announced the Council’s nominations of Officers and Council for President.-R. R. Tatlock. Past-Presidents (limited by the Society’s Articles of Association to eight in number).-M. A. Adams F.R.C.S. ; E. J. Bevan ; Bernard Dyer D.Sc.; Thomas Fairley; W. W. Fisher M.A.; Otto Hehner; Sir Thomas Stevenson M.D., F.R.C.P. ; J. Augustus Voelcker M.A. B.Sc. Ph.D. the Society’s accounts for the year 1907. 1908 as follows : Vice-Presideitts.-A. Bostock Hill M.D. ; E. W. T. Jones ; John White. Hon. Treaszmr.-E. W. Voelcker A.R.S.M. IiToilz. Sewetaries.-AAlfred C. Chapman ; P. A. Ellis Richards. Otlzer Members of Council.-Bertram Blount ; Cecil H. Cribb B.Sc. ; J. T. Dunn, D.Sc. ; A. E. Ekins; John Golding ; J. T. Hewitt D.Sc. Ph.D. M.A. ; Arthur R. Ling ; L. Myddelton Nash ; F. W. Richardson ; H. Droop Richmond ; G. E. Scott Smith; L. W. Stansell 2 THE ANALYST. The following papers were read ‘‘ The Action of Dimethyl Sulphate (Valenta’s Reagent) upon Oils of the Aromatic and Aliphatic Series,” by T. W. Harrison B.Sc., and F. Mollwo Perkin Ph.D. ; ‘‘ Titration with Permanganate in Presence of Hydro-chloric Acid,” by T. W. Harrison B.Sc. and F. Mollwo Perkin Ph.D. ; “ Routine Methods for the Bacteriological Examination of Water,” by Arnold R. Tankard ; and “The Quantitative Separation of Barium from Strontium,” by Miss Zelda Kahan B.Sc

ISSN:0003-2654    

DOI:10.1039/AN9083300001

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

2 THE ANALYST. THE ACTION OF DIMETHYL SULPHATE UPON OILS OF THE AROMATIC AND ALIPHATIC SERIES.* BY THOMAS WEATHERILL HARRISON, B. Sc., AND FREDERICK MOLLWO PERKIN, Ph.D. VALENTA (Chenz. Zeit., 19G6, 30, 266; ANALYST, 1906, 31, 202) has described the action of dimethyl sulphate upon aromatic and aliphatic oils, and mixtures of these. He pointed out that, since tar oils are often used to adulterate mineral oils, it is important to obtain a quantitative method for determining the one in presence of the other. Whilst it is not a difficult matter to distinguish between aromatic and mineral oils, or rosin and mineral oils, it is by no means 80 easy to distinguish a mixture in which aromatic or rosin oil is incorporated with the mineral oil. This chemist found that dimethyl sulphate dissolves oils of the benzene series, such as occur in coal-tar, at ordinary temperatures, and is miscible with them in all propor- tions.But it does not dissolve oils of the aliphatic series, such as petroleum ether, benzine, cleaning oil (putziil), or other petroleum oils in the cold ; it also has very slight action upon rosin oil. Consequently dimethyl sulphate is a good reagent for separating aromatic oils from aliphatic oils and quantitatively determining the proportions in the mixture. If the statements of Valenta are correct, they constitute w valuable addition to the analytical methods of oil separation and it seemed important to check this method, and, if possible, confirm it. Unfortunately, after a long series of carefully conducted experiments,we have not been able to do so.That aromatic oils are soluble in all proportions we agree, but that mineral oils are insoluble is not the case. In the first place we tested the action of dimethyl sulphate upon hydrocarbons of the aromatic series and of the aliphatic series separately. I n each case, unless otherwise stated, approximately 1Q volumes of dimethyl sulphate was taken to 1 volume of the oil. The oil was measured into a burette, and then the requisite volume of dimethyl ’sulphate added. The two substances were well mixed by shaking, and then allowed to stand until a clear line of demarcation was obtained. This generally occupied from half to one minute. * This y r k was carried out in accordance with the ternis of the “Analytical Chemistry Invcstiga- tion Scheme.THE ANALYST.3 TABLE I. ... ... . . . ... Spindle oil ... . . . Cylinder oil (sp. gr. 0-903) . . . . . . ... ... No. 1 Russian oil (sp. gr. 0.89i) ... ... ... 9 , 2 Y , ,, ( ,, 0.900) . . . . . . ... American (sp. gr. 0.875) ... ... ... ... ,, ( ,, 0.903) ... ... ... . . . Queen's spindle oil ... . . . . . . ... .-. Scotch oil (sp. gr. 0.885) ... ... ... ... Galician ... ... . . ... ... ... Petroleum ether ... Kerosene (sp. gr. 0.798) ... ... Mineral oil, 160" to 300" C. (kerosene) ... ... ,, 2 volumes of dimethyl sulphate ... Petroleum (Roumanian) (sp. gr. 0.803) ... ... Purified blast furnace oil ... ... ... ... Naphtha ... ... ... ... . . . No. 1 burning ... ... ... Shale Pearline sp. gr. (0.865 to 0.870) ... ... ... ... . . . ... . . . ... ...Form turbid emulsions, from which the oil only separates after a long time. Turpentine (American), 2 vol. of dimethyl sulphate Rosin oil :I: (sp. gr. 0*915), 1 volume of dimethyl Rosin oil, 2 volumes of dimethyl sulphste ... i oils 1G.s oil J ... Turpentine (Russian) ... ... sulphate ... ... ... ... ... ... l'erceii tnge dissolved. 3.3 0 2.3 0 5.0 1.1 4.4 7.6 7 -6 17.2 3.4 7.2 14.4 12.0 36.0 20.5 14.0 13.0 28.3 29.0 24.0 44.0 Olive oil forms an emulsion which gradually deepens in colour to brown. In a few minutes this separates into two turbid layers; none appears to dissolve. Cotton- seed and rape oil behave in a similar manner. Glycerine forms an emulsion which soon separates ; no coloration or rise in temperature takes place. By repeated extraction with dimethyl sulphate, it was possible to dissolve additional amounts of the hydrocarbon.For example, 80 per cent. of the Roumanian petroleum was dissolved, and in this case the dimethyl sulphate seemed to be saturated by 8.5 per cent. of its volume of the extracted substance--i.e., the dimethyl sulphate will dissolve 8.5 per cent. of the petroleum. With blast-furnace oil (purified by removal of the phenols and bases, and then by continued shaking out with concentrated sulphuric acid, until, on distillation, a permanently colourless product boiling at 200" to 240" C. was obtained) 70 per cent. was dissolved; in this case the point of saturation was 26% per cent. by volume. By using excess of the dimethyl sulphate, larger quantities of kerosene than mentioned in the table may be dissolved.Thus in three extractions, using 2-9 C.C. of kerosene and, in total, 14.3 of dimethyi sulphate, 16 per cent. was dissolved. A Scotch shale oil of unknown origin dissolved to about 5 per cent. of the sulphate used. In the case of Galician oil, dimethyl sulphate takes up 4 per cent. of its volume. * According to Valenta, oiily very slightly soluhIe.4 THE ANALYST, Cylinder oil is too viscid to employ for accurate experiments, as it cannot readily be shaken up, and if heated to render it more fluid, the conditions are altered. It was diluted with its own volume of petroleum ether and none of the mixture dis- solved ; this was unexpected, because petroleum ether per se does dissolve (17.3 per cent. in 1.5 volumes of dimethyl sulphatej. With American turpentine three extractions dissolved 70 per cent.of the turpentine ; the last separation mas not definite. Considerable heat was developed and the turpentine darkened. With Russian turpentine, 1;- volumes of dimethyl sulphate dissolved 28.3 per cent. of turpentine, 2$ volumes 40.6 per cent., and 3.7 volumes 46.2 per cent. The aromatic hydrocarbons are soluble and miscible in all proportions with methyl sulphate. Nitrobenzene, nitrotoluene, phenol, the cresols, and all bases are soluble ; in this latter case the reaction is very vigorous. Ethyl ether is also readily soluble. SEPARATION OF MIXTURES OF AROMATIC OILS WITH OILS OF THE ALIPHATIC SERIES. In the first series mixtures of commercial xylenes with various mineral oils were experimented with. Xylene and dimethyl sulphate, as already stated, are com- pletely miscible, but the mineral oils are themselves partly soluble.It was, however, thought that possibly the dimethyl sulphate would only attack the aromatic oil, and then be so diluted that it would have no further action upon the mineral oil. Valenta suggested that exactly 14 volumes of dimethyl sulphate should be taken, and unless otherwise stated we used this quantity. An examination of Table 11. will show that the results are not even concordant among themselves. It would be expected that the greater the quantity of the xylene, the less satisfactory the separation, owing to the difiiculty of dissolving it all out from the mineral oil. Consequently, the addition of a larger quantity of dimethyl sulphate in such cases should result in obtaining a larger percentage of the diesolved hydrocarbon.Take, for ex&mple, No. 1 ; here the increase to 2 volumes would appear to be a decided advantage, the amount of xylene dissolved out corresponding closely to the quantity that was present. But with No. 3 there are remarkable differences. Thus, with 1B volumes, 29 parts are extracted where 46 were added ; by employing 2 volumes, 38 parts are withdrawn, and this would appear to bear out the results obtained with No. 1; but then, when 22 parts of xylene are added, only 8 parts are extracted by means of 2 volumes of dimethyl sulphate. Even 18 volumes of dimethyl sulphate may work very well with large quantities of xylene, as shown by No. 7. Here, out of four dilutions, the best results are obtained with the lowest addition, 11 per cent., and the higheclt, 88 per cent., the intermediate extractions not being good. Petroleum ether was used because it was hoped it might be a diluent for thick oils; the numbers obtained in the mixture, and also separately, show, however, that it would be quite unsuitable.Valenta states in his paper that tar oil (boiling-point 240° to 300" C.) is largely In some cases this is so, but in others different results are obtained.1. 3. 3. 4. a. 6. 7. 8. 9. 10. 11. 12. 13. THE ANALYST. TAI~LE IT. Mixtures of Various Quantities of Xylene and Mineral Oils. 5 Oil. Spindle oil ... ... . . . 1 1 91 ... ... ... ... ... ... Russian, No. 1 (sp. gr. 0,903) Rus:ian, NO.'^ (sp. gl(.’O.SSi) 9 , 9 9 1 9 9 9 7 2 9 9 9 ) 9 1 9 9 American (sp.gr. 0,903) ... 9 7 1 9 9 9 7 7 9 9 1 1 ... ... ... Queen’s spindle (sp. gr. 0.900) Kerosene (sp. gr. 0*79S) ... 9 9 I 9 9 9 7 9 9 9 ... Galician (sp. gr. 0.884) . . . 9 1 2 9 1 9 9 9 9 9 9 9 ... ... ... Scotch (sp, gr. 0.885) ... American (sp. gr. 0.8’75) ... 9 1 9 9 ... 11 9 9 9 9 9 ) .. ... Petroleum (Roumanian) ... 9 9 9 9 1 9 9 ’ ... ... Petroleum ether ... ... Blast-furnace oil ... .., Rosin oil (sp. gr. 0,915) ... Percentage Volume of Xylem in Oil. 43 5s 43 23 35 33 46 22 46 51 27 36 51 17 47 50 11 22 48 88 18 47 31 41 65 28 59 51 19 51 32 9.6 Volume pe Cent. ah- sorbed. 36 49 41 9 21 25 29 8 38 41 27 29 48 17 37 12.5 43 12 16 36 8 4 13 36 28 33 57 33 61 52 24 72 54 Remarks. 2 vols. dimethyl sulphate 2 vols. dimethyl sulphate 2 vols.dimethyl sulphate 9 1 7 1 9 7 9 7 9 9 9 1 2 vols. dimethyl sulphate 7 7 11 2 vols. dimethyl sulphate 7 9 1 7 9 1 9 1 9 7 7 9 2 vols. dimethyl sulphate employed as an adulterant for mineral oils, and isoften added to varnishes and to colours for letterpress printing. We inquired from several sources whether such a fraction of tar oil was obtainable in this country, and whether it was used for adulteration purposes. Dr. G. W. Monier Williams, of the Gas Light and Coke Company, informed us that the only oil boiling about this range was one obtained from the creosote fractions, and mas generally known as ‘‘ sharp oil.” Mr. Wilton, the manager of the works, kindly supplied us with a specimen of this oil. I t was carefuIly purified from phenol by shaking up several times with 10 per cent.sodium hydroxide, and from6 THE ANALYST. TABLE 111. __ 1 2 3 4 5 6 7 8, 9, 10, 11, 12, 13. 14. - Oil. Spindle oil ... ... ... Russian, No. 1 ... . . . Russian, No. 2 ... ... ... ... ... 9 9 9 ) 9 9 '> 7 9 ... ... ... ... ... * . . 9 9 9 9 . 9 9 9 9 ... ... American (sp. gr. 0.903) ... 9 9 , 9 9 9 9 9 ... ... QueenJe spindle ... ... 9 9 9 9 9 9 9 9 9 ) 9 9 ... ... ... ... ... ... Kerosene (sp. gr. 0.7981) ... Galician (sp. gr. 0.8845) ... 9 9 ' J 9 9 9 9 ... ... 9 9 ... ' 9 ... ScoiLh ... ') ... ... ... 9 , ... ... 9 9 ... ... . I . American (sp. gr. 0.875) ... 9 9 Y Y ... Mi&al oil B (sp. i r . 0.8096j 1 9 9 J 9 , Y J Y Y ) J Petroleum, Roumanian ... Y Y 9 9 ... ... 7 9 NapiCha (shale) ... ... No. i' Burnilg (shale) ... Pediine ( s h e ) 'I..... ... 7, 9 8 9 9 ... 9 7 1 9 ... 9 9 ... 9 ) 9 Y ... -.. 9 9 9 9 9 9 9 , ... ... ... ... Volume Per Cent. of Coal-Tar Oil taken. 24 51 30 1 4 47 18 37 51 53 26 53 18 31 44 55 16 524 41 37 26 37 26 38 49 29 46 46 20 38 52 38 46 23 46 20 61 6 19 664 8 13 26 48 454 Volunie Per Cent. absorhed. 17 43 21 10 37 10 26 42 36 21 43 14 26 35 51 20 484 37 42 22 46 24 29 42 22 37 40 25 35 50 42 53 39 59 37 76 16 2% 454 70 18 17 30 50 Remarks. 3 vols. dimethyl sulphate 9 ) 9 7 2 vols. dimethyl sulphate 2 vols. dimethyl sulphate 9 9 9 9 Approx. 2 vols. dimethyl 2 vols. dimethyl sulphate 2 vols. dimethyl sulphate sulphate 9 9 9 , Approx. 2 vols. dimethyl sulp hate 2 vols. dimethyl sulphate 2 vols. dimethyl sulphate 2 vole. dimethyl sulphate7 THE ANALYST.bases by washing with sulphuric acid. It was then steam-distilled, and finally fractionated. The oil so obtained boiled from 190" to 270" C. ; it was slightly brown and quickly darkened. Therefore, if this is the oil which is used as an adulterant, it would necessarily be added in small quantities to colourless or very light oils. The oil was then employed as the adulterant, with the results shown in Table 111. As before, except where otherwise stated, the amount of dimethyl sulphate employed was 14 volumes. I t will be noticed that, although the numbers obtained with the heavier coal-tar oil are also erratic, they are slightly better than is the case with the lower boiling xylene. Taken on the average, the 9merican oils seem to give somewhat better results than the Russian or Scotch.I t is worthy of note that with the mineral oils the amount of tar oil extracted is less than the quantity put in, but with the shale, Roumanian, and Galician oils the volume extracted is greater than the volume of tar oil originally present. On referring to Table I. it will also be seen that the Galician, Roumanian, and the shale oils are also more soluble in the dimethyl sulphate than the American and Russian oils, But it cannot be said that in any case the numbers are quantitative, or approximately quantitative. Occasionally a quantitative result is obtained, but this must be purely a coincidence. For example, with Galician oil and xylene, 11 per cent. of xylene was taken, and 12 per cent. obtained. But the Galician oil is soluble to 7 per cent, Again, with No.1 burning oil (shale) 45.5 per cent. was added and obtained, the shale oil itself being soluble to 14 per cent. Since nitrobenzene is soluble in dimethyl sulphate, and it dissolves oils, Valenta suggests its use for diluting oils which are too thick to be conveniently shaken with dimethyl sulphate. We therefore experimented with certain oils containing tar oil diluted with nitrobenzene, with the following results : Mineral Oil. TABLE IV. Volume of Coal-Tar Oil Per Cent. American (specific gravity 0.903) ... Russian, No. 2 ... ... ... ... Queen's spindle ... ... ... ... Russian, No. 1 ... ... ... ... 9 , 9 , ... ... ..I 2 , - * . 9' - * a ... ... ... ... 9 7 ... ... 9 , ... 14 21 17 20.5 17 23 20 Volume of Nitrobenzene added. Volume Per Cent.absorbed. 31 15.5 30.5 36 23.5 37 26 The volume of dimethyl sulphate taken was in every case one and a half times the total volume of the oil plus nitrobenzene. After deducting an amount equal to the volume of nitrobenzene used, the remaining increased volume expresses the percentage absorbed. For example, in No. 1 the actual quantities taken were: American oil, 3.6 C.C. ; tar oil, 0.6 C.C. = 14 per cent..; nitrobenzene, 3.5 C.C. ; khe8 THE ANALYSTc total volume of the mixture being 7.7 C.C. Then 12.1 C.C. of dimethyl sulphate was added. After shaking up, the lower layer, which consisted of dimethyl sulphate and dissolved oil, was 16.9 C.C. ; therefore the increase was‘ 16.9 - 12.1 = 4.8 C.C. After deducting the nitrobenzene, 4.8 - 3-5 = 1.3 c.c., or 31 per cent.This table shows that the presence of nitrobenzene affords misleading results. Probably the solution of nitrobenzene in dimethyl sulphate has itself a solvent action upon the mineral oil. This is borne out by increasing the volume of the nitrobenzene, when it will be noticed far greater quantities of the mineral oil are dissolved by the dimethyl sulphate. Seeing that the volumes of the *‘ coal-tar oil ” extracted were in most cases less than the theoreticd, and that the mineral oils are distinctly soluble in dimethyl sulphate, we expected to find a portion of the dimethyl sulphate would be found dissolved in the layer of mineral oil. The upper layers, obtained from Queen’s spindle oil plus tar oil, and from kerosene plus tar oil, were boilvd with alcoholic potash, the alkaline solution separated from the oil, acidified with hydrochloric acid after dilution with water, and barium chloride added, Only a faint opalescence was produced, showing that the dimethyl sulphate had not dissolved in the mineral oil, but that the failure to extract the whole of the tar oil was due to a portion of it remaining dissolved in the mineral oil., Recently Graefe (Chem. Rev. Fett. ZL. Harx. had., 1907, 14, 112; ANALYST, 1907, 32,225) submitted the ‘ I Valenta method ” to a systematic examination. He confirins our experiments in so far as that the mineral oils of low boiling-points are decidedly soluble in dimethyl sulphate. Thus, 1 volume of dimethyl sulphate dissolves 15 per cent. of ligriiin, 2 volumes 22 per cent., and 4 volumes 34 per cent.‘‘ The solubility, therefore, is proportional to the volume of dimethyl sulphate employed.” He also gives the solubilities of brown coal oils, which may be compared to shale oils, and of petrol oils, with 14 volumes of dimethyl sulphate. TABLE V. Brown Coal Oils. Per Cent. Benzin (sp. gr. 0.792) ... ... 20 Solarol (sp. gr. 0.827) ... ... 30 Rotol (sp. gr. 0.879) ... ... 24 Gasol (sp. gr. 0-892) ... ... 29 Hesvy oil (sp. gr. 0.918) ... ... 18 Petrol Oils. Per Cent. Light oil (sp. gr. 0.651) ... ... 12 Heavy benzin (sp. gr. 0.735) ... 15 Russian petrol (sp. gr. 0.821) ... 6 0.7YO) ... ... ... ... 4 Galician petrol (sp. gr. 0.805) ... 7 American water, white (sp. gr. When the solubilities of these oils in dimethyl sulphate and the complete solubility of aromatic hydrocarbons are considered, the results he obtains with mixtures are surprising.For example, a mixture of Russian petroleum and tar oil was treated with 13 volumes of dimethyl sulphate, with the results shown in Table VI.THE ANALYST. Percentage Tar Oil Taken. 9 Percentage Percentage Tar Oil Percentage Dissolved. 11 Taken. Dissolved. TABLE VI. Percentage Tar Oil Taken. 10 20 30 40 50 Percentage Dissolved. Percentage Tar Oil Taken. 12.5 20.0 30.0 40.0 50.0 60 70 80 90 Percentage Dissolved. 61 75 85 97 Russian petroleum is, according to his figures, soluble to 6 per cent. Again, gas oil, which he found to be soluble to the extent of 29 per cent. in dimethyl sulphate, gave the following results when mixed with tar oil : TABLE VII. 10 20 30 40 50 11 20 30 39 50 60 70 80 90 60 70 81 91 I I1 I The most remarkable case is perhaps that of brown coal oil and tar oil.Here the error is always about 10 per cent.; therefore, by subtracting 10 per cent. from the numbers obtained, correct results are arrived at. But when dealing with unknown oils such a calculation is not possible. I n connection with the greater solubility of the Galician and Roumanian oils in dimethyl sulphate, it should be noticed that these oils are stated to contain small quantities of aromatic hydrocarbons (Joum. Clzem. Soc., 1907, 91, 883). CONCLUSIONS.--TO quantitatively estimate the quantity of aromatic oil mixed with a mineral oil, Valenta’s method cannot be recommended. If an accurate result is arrived at, it is a coincidence. When dimethyl sulphate is shaken up with hydrocarbons of the aromatic series mixed with mineral oils, the bulk of the aromatic oil is dissolved, and in most cases only a small quantity of the mineral oil.If the dimethyl sulphate layer be saponified with alcoholic potash, on diluting with water and extracting with ether, the hydrocarbon‘oil mixed with only a small portion of mineral oil, is recovered. It can then be tested, to prove that it is an aromatic oil. The fact that dimethyl aulphate dissolves a portion of an oil is no proof that the dissolved portion is an aromatic hydrocarbon. Consequently, it is essential to saponify and employ additional tests. As a qualitative method it is of use. Hoiiocc:ii POLYTECHNIC INSTITUTE, LONLJON.10 THE ANALYST. DISCUSSION. The PRESIDENT remarked that in two cases the solubility seemed to be in inverse ratio to the specific gravity, but, of course, one could not judge properly from these instances alone.Mr. L. MYDDELTON NASH asked for particulars of the spindle oil referred to. American oil (specific gravity 0.885) was generally known as spindle oil, but this oil had been mentioned separately. He should like to hear something about the (‘ blast- furnace oil,” as the name was unknown to him. The authors had .spoken of Roumanian petroleum as well as kerosene. What was the kerosene uqed? A good deal of the kerosene now on the market consisted, he believed, of Roumanian, or a blend of Roumanian and some other petroleum, probably Texas. In the case of rosin oil there were considerable variations in composition, some kinds being more or less free from acid, while others contained a great deal, depending on the method of manufacture.Possibly the reason that the authors’ results differed from those of Valenta was due to the acidity or neutrality of the oils 3 If the oil were free from acid, it might be insoluble, whereas if it contained much acid, the solubility might be accounted for, Would the authors say whether they considered that the proportion of mineral oil in an adulterated rosin oil could be determined by this method with m y degree of accuracy? He had never met with tar oil in mineral oil, but was surprised that no mention had been made of Borneo oil., of which a great quantity was used. I t was an interesting oil in that its fractions differed from similar fractions of other mineral oils in some of their properties, and would probably behave differently from them with dimethyl sulphatc.Mr. RICHMOND asked whether, if the oil were treated with three successive quantities of 18 volumes of the reagent, the same or practically the same diminution of volume was observed each time. Dr. PERKIN said that as far as he remembered the difference in volume wag slightly less on each successive occasion, but for practical purposes it might be regarded as approximately constant.‘:: Mr. RICHMOND said it had occurred to him that possibly, by two or three succes- sive treatments, the proportion of aromatic oil present might be determined with considerable accuracy. He was reminded of some experiments which he had made on the analysis of mixtures of ether, petroleum ether, and alcohol.It was found that, when such a mixture was shaken with water saturated with ether, in order to estimate the alcohol, the petroleum ether dissolved from the water a certain quantity of ether. The ethereal layer was shaken a second time with etherised water, the second reading affording data for the correction of the results of the first. Probably in a single treatment with dimethyl sulphate the aromatic oils would dis- tribute themselves between the reagent and the hydrocarbon oils, according to the well-known solubility law, and so be incompletely extracted ; but with successive extractions one might not only be able to deduce the volume of the aromatic oil present, but also approximate closely to the amount of hydrocarbon oil dissolved, and * On fiirther examination of the nnmbers obtained, the nutliors find that the differences are not suficicntly constant to serve even approsiniately as a quantitative guide.THE ANALYST.11 possibly thus get some idea of the nature of the latter. He would also suggest that the authors should, if they had not already done so, make similar experiments with mixtures of hydrocarbon oils and aroniatic oils, as he thought the results would show that by the application of simple corrections the very crude determinations obtained by a single estraction could be rendered very much more accurate, Dr. PERKIN said that in one case in which they had tried successive treatments they had found it possible to dissolve a hydrocarbon oil in increasing quantity up to 80 per cent.In that particular case the dimethyl sulphate seemed to be saturated to the extent of 8.5 per cent. of its volume-a ratio which was approximately constant. Mr. CHAPMAN remarked that this paper afforded an excellent example of the kind of work with which the Council's investigation scheme was intended to deal. The statements made by Valenta were such that one might have expected the method soon t o become a standard ono, but the authors, in showing that the results, generally speaking, were unsatisfactory, had probably saved others a good deal of laborious work, and prevented the obtaining of results which afterwards could not have been confirmed. He asked for the authors' views as to the reputed poisonous properties of dimethyl sulphate, which were said to render it objectionable to mork with. Dr. PERKIN said that the rosin oil they had used was obtained from Messrs. Butler, of Bristol. I t was washed with alklali, steam-distilled, and fractionated, a colourless oil being thus obtained which had a specific gravity of 0.915 and boiling- point 130" to 200" C. Such oil, but generally of a lower boiling-point and specific gravity, was often used for adulterating turpentine, and for this purpose it must be colourless. In the few cases in which no solution took place the oils were very heavy cylinder oils, so it seemed as though the solubility did vary inversely as the specific gravity, as the President had suggested, although no quantitative rule could be given. The spindle oil was a moderately thin American oil, but not particularly thin for spindle oil. It was the kind of oil usually used for light machinery. They would be lnuch interested in examining the Borneo oil referred to by Mr. Nash, if he would let them have a sample of it. The reagent had a slight odour of sulphurous acid, but otherwise they had no observations to make on the poisonous properties of dimethyl sulphate. I n any case, as they always worked at atmospheric temperatures, there was not much danger of inhaling the vapour.

ISSN:0003-2654    

DOI:10.1039/AN9083300002

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

IS THE ANALYST. QUANTITATIVE SEPARATION OF BARIUM FROM STRONTIUM.* BY ZELDA KAHAN, B.Sc. Introd~~ctory.-From time to time various attempts have been made to separate barium, strontium, and calcium quantitatively. The best method so far employed is undoubtedly that of Skrabal and Neustadl (Zeit. anal. Chenz., 1905, 44, 742); but even this one is based on the double precipitation of the barium, and is conse- quently both troublesome and hardly likely to lead to very accurate results. Moreover, experiment has shown that some of the details given for effecting the estimation might lead to serious errors. Thus, ignition of the precipitate in a platinum crucible is recommended, but in doing this the precipitate almost invariably turns green, and the yellow colour is not restored on further heating; also; when a Gooch crucible containing barium chromate thoroughly dried at 200" C.was placed in a larger crucible and heated to redness for about five minutes, the precipitate thrned slightly green and lost nearly 2 mgm. in weight. E~z~eri?neiztaZ.-Starting from the idea that the solubility of barium chromate depends on the number of free acid hydrogen ions in the solution, ammonium acetate was employed to diminish the acidity. To avoid a double separation of the strontium it is necessary that the minimum amount of strontium chromate should be formed, Consequently, only the least possible excess of ammonium bichromate was used for precipitation. When ammonium bichromate is added to an aqueous solution of barium chloride, a precipitate is not immediately formed ; but if ammonium acetate is added, a precipitate separates at once, even if there be only a trace of barium salt present ; and if insufficient chromate has been added, the solution very soon becomes colourless.When the same experiment is performed with a strontium salt, a yellow solution is formed, but no precipitate separates even on standing overnight. If in either case the solution is boiled, it turns slightly green ; all the experiments were therefore performed in the cold. The following solutions were prepared : I n the later experi- ments 60 C.C. of this solution wag made up to 500 C.C. The salts employed were usually purified by repeated recrystallisation. 1. Ammonium bichromate, containing 120 grams per litre. 2. Neutral animonium acetate, containing about 300 granis per litre.3. Barium chloride, containing 0.1109 Ba per 10 C.C. Estimated in the soh- 4. Strontium chloride, containing 0.0651 Sr per 10 C.C. } tions as sulphate. The experiments described below were performed in the following manner : Measured volumes of barium and strontium chloride solutions were introduced in a beaker, and the solution made up to a definite volume. The bichromate was then added drop by drop with constant stirring, until precipitation was nearly complete ; then ammonium acetate until the solution became colourless; a few more drops of chromate were added, so that the solution became very pale yellow, after which * This work was carried out iii accordance with the twins of the '' Analytical Cheiliistry IIlvestiga- tion Scheme."~ No.~ 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. - 3aCrO, found. Volume of Solutions used. Ba. Theory for 10 C.C. =0'1109. 10 C.C. BaCl, 10 C.C. SrCl, 1 I 1 10 C.C. BaCl, 10 C.C. SrCl, 10 C.C. BaCI, 10 C.C. SrC1, 10 C.C. BaC1, \ 10 C.C. SrCl, 10 C.C. BaCl, 20 C.C. SrCl, 10 C.C. BaC1, 7 20 C.C. SrCl, 10 C.C. BaC1, 7 20 C.C. SrCl, 10 C.C. BaCl, 7 20 C.C. SrC1, J 20 C.C. BaC1, 7 10 C.C. SrCI, 1 10 C.C. BaCl, 1 40 C.C. SrCl, J 10 C.C. BaCl, 1 30 C.C. SrCl, J 3.2095 0.2110 0.2039 0.2015 0.2044 0.1977 0.2026 0.2037 0,4090 0.2017 0.2052 VOl. 100 C.C. 50 C.C. 100 C.C. 150 C.C. 150 C.C. 150 C.C. 150 C.C. 150 C.C. 250 c.c, 150 c.c 200 c.c 0.1135 0.1145 0.1105 0.1092 0.1108 0.1072 0.1099 0.1104 0.2217 0.1094 0.1115 dolume of Bichro - mate. About I C.C.in excess. - A few hops in excess. - 1 or 2 drops in excess. - - - - - -- rotal.Am- monium Acetate. 18 C.C. added before precipi- tation. - 6 C.C. - - 8 C.C. 3 C.C. 3 C.C. 2.5 C.C. 3 C.C. 3 C.C. I Error. + 0.0026 + 0-0036 - 0.0004 - 0*0017 - 0*0001 - 0.0037 - 0 0010 - 0.0005 - 0*0001 - 0.001t + 0.0002 SrSO, found. 3.1326 3.1320 - I 0.2766 - 0.2764 - - - 3.40'75 Sr. Theory for 10 C.C. =0'0651. Error. - 0*0018 - 0.0021 - - t 0.0017 - + 0~0016 - - - - 0.001 Strength of Ammonium Acetate used in Washing Precipitate. Per Litre. 40 C.C. 30 C.C. 20 C.C. 25 C.C. 30 C.C. 40 C.C. 20 C.C. 20 C.C. 20 C.C. 20 C.C. 300 c.c.use( 20 C.C. Further Remarks. The strontium was here estimated as sulphate, with previous coiirer- sion into carbonate. Stood orcrnight before filtering. Stood overniglit.The motlier-liquor of Ex- periments 3 t o 11, tested spectroscopically, con- tained no barium; but thewash-solution, tested in the same way, showed the I'resence of bariiiiii, which, however, was not precipitated on standing overnight.14 THE ANALYST, more ammonium acetate was added. After allowing the beaker and its contents to stand for a certain time, the precipitate was filtered through a Gooch crucible. I t was first washed by decantation four or five times with diluted ammonium acetate, and then in the Gooch crucible until the filtrate gave only a slight coloration with neutral silver nitrate solution. The crucible was dried at 180" to 260' C. When a constant weight had been obtained at 180" C., there was no further change on heating even above 260" C.The crucible should be left in the balance case at least an hour before weighing. The experimental results given in the table are some of the typical ones obtained. An attempt was made to deduce a volumetric method for estimating the barium by means of ammonium bichromate, but the yelIow precipitate interferes, and the point at which the change in colour occurs cannot, therefore, be determined sufficiently accurately. All attempts at effecting the separation of barium and stron- tium by means of their titanium, vanadium, and molybdenum salts were unsuc- cessful. I t is thus evident that the results obtained, although not very accurate, are yet not inferior to those obtained by Skrabal and Neustadl; b n the other hand, this method has the advantage of being quicker and easier to execute. Possibly, too, with some modifications, it may be made to yield very accurate results, especially when the proportion of barium to strontium is relatively large. It was noticed that unless the vessel in which the barium chloride solution is kept is previously well steamed, a small quantity of precipitate-probably barium silicate-is formed after four or five days' standing. In conclusion, I wish to thank Sir W. Ramsay for the interest he has taken in the work during its progress. UXIVEIlSITY COLLEGE, 60\VEll STKEET, LOSl>O?;.

ISSN:0003-2654    

DOI:10.1039/AN9083300012

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

14 THE ANALYST, ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. Sensitive Reaction for Antipyrin. F. A. Steensma. (.Phnrm. Zeit., 1907, 52, 851 ; Pharnz. Jozcm., 1907, 79, 677.)-An acid alcoholic solution of para-dimethyl- amidobenzaldehyde gives a bright red colour with as little as 0.001 mgm. of antipyrin, even in the presence of pyramidon, when a little of the substance, solid or in solution, is evaporated to dryness at 100' C. with 5 C.C. of this reagent. The test-solution is prepared by dissolving 1 gram of para,-dimethylamidobenzaldehyde and 5 C.C. of 25 per cent. hydrochloric acid in absolute alcohol, and making up with alcohol to 100 C.C. For the detection of minute quantities of antipyrin the test-reagent should be diluted with an equal volume of water.A. R. T.THE ANALYST. 15 Coloration of Brown Bread. G. Bertrand and W. Mutermilch. (Bull. SOC. Chirn., 1907 [iv.], 1, 1048-1051.)-As the result of their experiments, the authors find that the colour of brown bread is due to the action of a ferment existing in wheat bran. The action takes place in two stages : in the first a protease, which it is proposed to call glutenase, sets free a colourless chromogen having the characteristics of tyrosine, whilst in the second stage atmospheric oxygen combines with this chromogen to produce the brown colour. The glutenase is active only in neutral or acid solutions ; it hydrolyses the proteins of flour, and also casein, with the production of tyrosine. w. P. s. Estimation of Cineol in Eucalyptus Oil.Schimmel and Co. (Senzi- zlizizual Report, October, 1907, 45.)--The method depends upon the solubility of the addition-product which resorcinol forms with cineol, in a, concentrated solution of resorcin itself. Ten C.C. of the oil are thoroughly shaken for five minutes in a Hirschsohn flask (of 100 C.C. capacity) with about 70 C.C. of a 50 per cent. aqueous solution of resorcinol. A further quantity of resorcinol solution is then added to bring the insoluble portion of the oil into the graduated neck of the flask, where it is measured after it has stood sufficiently long to allow the insoluble portion to separate completely, and the lower layer of resorcinol solution is practically clear. The percentage of cineol by volume is obtained by difference. The resorcinol can be recovered from the solution by evaporation to dryness, which treatment expels the cineol present.Oils rich in cineol are diluted with an equal vohme of turpentine oil, and 10 C.C. of this mixture used for the determination, by which means crystallisa- tion of the whole liquid is prevented. The test-analyses are good, and show the method to give somewhat high results, but within 2 per cent. of the truth. The United States Pharmacopoeia method (using phosphoric acid) is shown to be unsatisfactory. A. R. T. The Composition of the “Crude Fibre” of Cacao. H. Matthes and F. Streitberger. (Ber. deut. Chem. Ges., 1907, 40, 4195-4199.)-Konig (ANALYST, 1906, 31, 406) has suggested that his method for the estimation of cellulose, lignin, and cutin in “ crude fibres ” might be useful for detecting the presence of husks in powdered seed-products, such as cocoa or pepper.Fincke (,~NALYST, 1907,32,172), on investigating the process in the case of cocoa, found, however, that the determination of these constituents gave no more reliable information as to the purity of the sample than was afforded by the yield of total (‘ crude fibre ” itself. The authors have also examined the method as applied to cocoa powder, and find that the crude fibres ” prepared from the same sample by different methods vary both in yield and com- position. All of them contain coloured extractive matters and greater or smaller quantities of nitrogenous matters, these impurities being determined as (( lignin ” in Konig’s process. Moreover, the reagent employed for removing the lignin (ammoniacal hydrogen peroxide) is not without action upon cellulose itself, since filter-paper, when treated with it, not only loses 3 to 4 per cent.or more in weight, but is broken down into a powdery, hygroscopic product. The amounts of so-called cellulose, lignin, and cutin varied very greatly in the preparations of I ‘ crude fibre ” obtained by different16 THE ANALYST. methods. For instance, the '' crude fibre" obtained by Weende's method, with a, yield of 7-83 per cent., showed a ratio of lignin : cellulose of 1 : 0.95; that prepared by Konig's method (yield 12.56 per cent.) showed a lignin : cellulose ratio of 1 : 0 5 (Fincke, Zoc. cit., found 1 : 0*6), and this preparation, after extraction with boiling alcohol according to Matthes and Miiller (yield 7-34 per cent.), showed a ratio of 1 : 1.37 : the '( crude fibre " obtained by Ludwig's method (yield 6.21 per cent.) had a lignin : cellulose ratio of 1 : 2.87.crude fibre" it is always necessary to specify the method employed, since a reduction in yield appears to be accompanied by an increase in the '' cellulose." A satisfactory separation of lignin from cellulose by Konig's method is not possible in the case of cacao. Thus in estimations of J. F. B. Analyses of Ginger and Extracted Ginger. R. Reich. (Zeit. Untermch. Nahr. Ge?zz6ssm., 1907, 14, 549-567.)-For the valuation of ginger and for the detec- tion of adulteration in the same it is recommended that estimations be made of the volatile and non-volatile ether extract, the alcohol extract, the alcohol extract after extraction with ether, the petroleum spirit extract, the methyl-alcohol extract, the mineral matter, and the separation of the latter into its soluble and insoluble con- stituents.The following are the average percentage results obtained from the analyses of eighty-seven various samples of ginger : Ether Extract. Icnhol Extract. Mineral Matters. e a, c, B Kind of Ginger. a 3 ta 11 *64 12.59 10'40 4.18 4.98 3 -33 2'33 2-96 1-64 0.15 0.20 0.05 1-38 1-65 1 -05 3 '40 3.77 3 '02 Average ... ... Lowest ... ... Highest ... ... 3.96 4.54 3-49 5 *SO 6-44 5.08 2.19 2 '49 1.95 3.06 3 *72 2.51 4'43 4'94 4'14 7-19 7 '86 6'26 1 *eG 2.11 1'49 3.45 4'46 2.69 4.65 6.44 3-24 7.06 9.33 5 *48 - 2-04 3-04 1 5 2 0 -30 0.52 0.14 1 *39 1 -89 0.90 4.48 5-16 3 * i 2 11%8 13-80 9-20 12.51 13'85 11-69 Lowest ...... (Average .. . .. . Bengal Highest ... ... Average ... ... Lowest ... ... (Lowest ... .., 3-45 4-51 2.56 2.05 3.79 1.21 1-60 2-15 1.15 1 *88 2-98 1'12 4-36 5.35 3-24 2-46 3.09 1-96 5'43 6 - 4 6 3'82 3-97 4'94 2.94 6 5 0 8.08 5 '66 12-74 13.65 11'16 4-37 6 '22 3 *29 1.97 2-56 1 '63 0'84 2.47 0 -08 2-54 3-08 2-10 T '47 9'58 6'22 1-54 1 -90 1 -70 2.42 1 a39 0.67 0.55 4-64 5 . 7 i 3'19 0.69 0-54 6 *64 5 -05 5 *so 1.50 1 -30 Extracted Cochiii Ginger . . . ,, Bengal Ginger ... 3 '28 4.52 - 0.48 0 '46 1.32 1 *18 0.99 1 '93 0.11 0.97 13.26 13'42 The last two samples had been extracted with alcohol for the preparation of ginger essence. w. P. s. * Winton, Ogden and Mitchcll, 22nd and 23rd Annual Report of the Connecticut Experimental Agricultural Station.THE ANALYST.17 Estimation of Cotarnine, Codeine, and Morphine by Means of Dinitro- phenylmethylpyrazolone. H. Matthes and 0. Rammstedt. (Zed. a d . C7zemg, 1907, 46, 565-574.)-The authors have already shown (ANALYST, 1907, 32, 216) that strychnine, brucine, hydrastine, and pilocarpine can be estimated by means of the insoluble salts they form with dinitrophenylmethylpyrazolone (picrolonic acid) ; similar salts are formed in the case of cotarnine, codeine, and morphine, and the method now described is based on this reaction. It is particularly applicable to the estimation of the alkaloids in the presence of sugar. A quantity of tbe powder or tablet under examination, containing about 0.5 gram of alkaloid, is dissolved in a little water and precipitated by the addition of a few C.C.of -& alcoholic picrolonic acid solution. The picrolonate soon separates out as a yellow crystalline powder, and, after standing for fifteen hours at the ordinary temperature, is collected cn a weighed asbestos filter, washed with the least possible quantity of water, dried at 1 1 0 O C . for half an hour, and weighed. The composition of the salts is : cotarnine picro- lonate, C,,H,,N0,.C,,H,N,05 ; codeine picrolonate, C,,H,,N O,.C,,H,N,O, ; morphine picrolonate, C,7H,,N0,.C,,H,N,0,. w. P. s. Examination of Jalap Resin. Deer. (Jpoth. Zcit., 1907, 22, 861; Clwn. Zcit. Rep., 1907, 31, 555.)-To identify and test the purity of jalap resin, 1 gram of the powder is shaken at intervals during six hours in a stoppered flask with 10 grains of ether (free from alcohol), the liquid filtered, the residue washed three times with 5 or 6 C.C. of ether, the filtrate and washings evaporated, and the residue dried at 100" C.This residue, which should not amount to more than 0.1 gram, is insoluble in hot ammonia solution. The portion of the resin insoluble in ether when dried on the water-bath, and heated to 30" or 40" C. with 5 grams of ammonia solu- tion in a closed flask, should yield a clear solution, which does not become turbid for some time when diluted with twice its volume of water and acidified with dilute acetic acid. The presence of colophony (in excess o€ 5 per cent.) and of guaiacum resin may be detected by adding a drop of concentrated sulphuric acid to a solution of 0.02 gram of the jalap resin in 2 C.C.of acetic anhydride. A rose coloration (or blood-red when the amount exceeds 10 per cent.) indicates the presence of colophony, whilst with guaiacum resin the colour becomes dirty green. C. A. M. Analyses of Condensed Milk. F. J. Lloyd. (Clierr~. Ncios, 1907, 96, 225.)- The author finds that the brands of conclensed milk most frequently sold in this country are machine-skimmed products containing about 1 per cent. of fat, and many vendors sell no other kind. Only three brands of full-cream milk, one of these an unsweetened product, appear to be at present on the market. I n each case the condensation had been carried to tho extent of about one-third of the original volume. Although one sample of machine-skimmed milk prepared in Holland bore the label ( ( Unsuitable for the use of infants and invalids," this warning is not always given.Even in the case of one of the full-cream milks, the directions on the label stated that for puddings, tea, etc., the milk may be diluted with 4 or 5 parts of water. There can thus be little doubt that many users of condensed milk dilute the pro- duct until it becomes practically a, mixture of equal parks of normal milk and18 THE ANALYST. 0*10-1'85 0'03-0*05 0'70-1'40 water. that of fresh milk. A. R. T. The price of these condensed milks compares in all cases unfavourably with 30'6-42'7 13'04-16*30 0*26-1*04 15'3-19*0 24'34-26'88 1.19-1 '28 4.4-5'55 30'44-32'60 0*54-0*96 Estimation of Fat in Milk. H. Timpe. (Chem. Zeit., 1907, 31, 1107-1108.)- I t has been shown previously (ANALYST, 1899, 24, 205) that Soxhlet's areometric method for the estimation of fat in milk resulted in too low results being obtained, and that the loss was due to the saponification of a small, but varying, quantity of the fat by the alkali employed.The following modification of the process is there- fore proposed, sulphuric acid being used instead of alkali to dissolve the proteins, etc., of the milk : Fifty C.C. of concentrated sulphuric acid are added gradually to 100 C.C. of milk ; when the casein is completely dissolved, 50 C.C. of water are added and the mixture is cooled. The solution is now shaken with 60 C.C. of dry absolute ether, the ether is allowed to separate, and its specific gravity determined.From the latter the percentage of fat in the milk is ascertained, as in the original Soxhlet method. w. P. s. 1'54-3'62 0*80-1*03 1.68-2'14 Estimation of the Specific Gravity of Milk Serum. N. Schoorl and F. Con. (Zeit. Untersuch. Nahr. Gemsswz., 1907, 14, 637-643.)-Experiments are described in which the coagulation of milk by acetic acid, as a preliminary operation in the estimation of the specific gravity of milk serum, is investigated. The influence of the amount of added acetic acid, the temperature, and time of heating are ascertained, and the following method of obtaining the serum is recommended : One hundred C.C. of milk are treated with 2 C.C. of 20 per cent. acetic acid, and the mixture is heated for two to five minutes in a water-bath, at a temperature of 70" to 75" C.After rapid cooling, the solution is poured on a filter, the first 10 C.C. of filtrate is rejected, and the remainder of the filtrate is used for the determination of the specific gravity. The above-mentioned acetic acid has a specific gravity of 1.0284 (15'/15' C.), and the addition of from 2 to 5 C.C. to 100 C.C. of milk has practically no influence on the specific gravity of the serum, the actual difference between the two quantities being 0.00003. Many more analyses must be made before fixing limits for the specific gravity of milk serum thus obtained, but the process has advantages (rapidity, etc.) over the methods in which the milk is allowed t o curdle spontaneously. W. P. S. 6'02-8'81 3.64-4-75 4-32-6'68 Analysis of Black Pepper, and the Detection of Adulterants in the Same. F. Hartel and R. Will. (Zeit. Untersuch. Nahr. Genussm., 1907, 14, 567- 579.)- The following results were obtained on the analysis of fifteen samples of black pepper, the figures expressing percentages on the air-dry material. Three samples of pepper hulls and two examined. samples of empty or sterile (taube) peppercorns were also Dextrose Crude Resin. Sand' 1 Value. 1 Fibre. 1THE ANALYST* 19 The authors consider that a good grade black pepper should not contain an undue proportion of empty corns ; the samples to which the above figures refer contained less than 15 such corns per 100 peppercorns. For the detection of hulls and empty corns, estimations OE the crude fibre aud ‘‘ dextrose value ” (ANALYST, 1907, 32, 292) of the sample give the most useful data. If the amount of crude fibre in a sample exceeds 17 per cent., and the ‘‘ dextrose value ” be lower than 30 per cent., the pepper is almost certainly adulterated with hulls. The ash should not exceed 6-5 per cent. w. P. s.

ISSN:0003-2654    

DOI:10.1039/AN9083300014

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

THE ANALYST* 19 BACTERIOLOGICAL, PHYSIOLOGICAL, ETC. The Guaiacum Reaction for the Detection of Blood. A. Bolland. (Zeih. anal. Chem., 1907, 46, 621-643.)-The following modification of the guaiacum test is recommended for the detection of blood in the presence of iron, iron-rust, or ferrous salts. The substance to be tested is moistened with 1 C.C. of concentrated ammonia, and then set aside at the ordinary temperature for from twenty-four to forty-eight hours, until the ammonia has evaporated. From 3 to 4 C.C. of water are then added, and, after the lapse of 8: few hours, the solution is filtered, and the filtrate evaporated on the water-bath to a small volume. To the residue are added 0-15 C.C. of 1 per cent. citric acid solution, 5 C.C. of 0.5 per cent. alcoholic guaiaconic acid solution, and 1 C.C.of oil of turpentine, and the mixture is shaken. If only 0-0007 gram of hzmoglobin be present, a positive reaction will be obtained. I t is shown that, under the above conditions, the coloration is t h e to the presence of blood, and not to that of iron salts. The action is perfectly sensitive with blood four months old. w. P. s. Estimation of Pepsin in Gastric Juice by Means of Ricin. J. Witte. (Bed klin. Woch. Apoth. Zeit., 1907, 22, 930; Pharm. Journ., 1907, 79, 677.)- The gastric juice, diluted with water, is filtered and further diluted, nearly neutral- ised with TG sodium hydroxide solution, and made up with water to a 1 per cent. solution. Half a gram of commercial ricin is dissolved in 50 C.C. of 5 per cent. sodium chloride solution, and the solution filtered.A series of five numbered tubes is prepared, each containing 2 C.C. of the ricin solution, and to the first four tubes 0.5 C.C. of =& hydrochloric acid is also added, causing a thick turbidity. To tube 1 is now added 0.1 C.C. of the 1 per cent. gastric juice and 0.9 C.C. water; to tube 2, 0.2 C.C. juice and 0.8 C.C. water; to tube 3, 0-5 C.C. and 0.5 C.C. ; to tube 4, 1 C.C. of the 1 per cent. gastric juice. These dilutions represent 1 : 1000, 1 : 500, 1 : 200, and 1 : 100. Tube 5 contains the ricin solution and 1 C.C. of water, and acts as a control. The tubes are kept at blood-heat for three hours, when the tube containing a practically clear solution is noted. The proportion of pepsin is expressed in units, 100 units indicating the pepsin content of 1 C.C.of gastric juice, which gives a clear solution when diluted and treated as described. This is the strength of the normal secretion. A. R. T. A Quantitative Measure of Proteolytic Action : Titration of Amino Acids in Presence of Formaldehyde. S. P. L. Sorensen. (Conzptes reyzd. du Lab. de Carlsbcrg, 1907, 7, 1-55.)-The essential structural type which characterises theTHE ANALYST. proteins is represented by a collection of amino-acid residues, linked together by anhydride bonds between the amino group of one unit and the carboxylic group of another-this is the polypeptide linkage. When such a body undergoes hydrolysis by the action of acids or proteolytic enzymes, these anhydride bonds are broken, the molecule is split at that place, and amino and carboxylic groups are opened out.A method which permits of the determination of either of these groups affords a measure of the degree of proteolytic action at any stage, and an indication of the position of the products on the scale of complexity. The method now standardised by the author is based on the reaction, first studied by Schiff, whereby the basicity of the free amino groups is masked by conversion into methylene derivatives by the addition of formaldehyde, whilst the acidity of the carboxylic groups is for that reason fully developed. The reaction in the case of alanine is formulatcd by the following equation : CH3.CR.NH2.COOH +H,C:O + HOH = CH,.CH.N:CH,.COOK + 2H20 Schiff failed, however, to arrive at a satisfactory acidimetric method, because the reaction is reversible, and the results are seriously affected by variations in the quantities of the substances brought into play.The tendency for the reaction to proceed in the desired direction is, however, increased by largely increasing the quantity of formaldehyde present, and decreasing the quantity of water. An increase in the concentration of hydroxyl ions or a decrease in the hydrogen ions has a similar effect. For this reason, in performing the titration, it is best to use an indicator which changes colour at a very low concentraqtion of hydrogen ions. In using phenol- phthalein, three phases, ranging from pale pink through distinct rose up to a vivid red, are available as neutral points, and the last, the most alkaline of these, yields the best results for the estimation of the amino acids in presence of formaldehyde.For instance, in water only 2 drops of alkali are sufficient to determine the change from the second to the third of these phases, but in the titrat'ion of some of the amino acids there may be a difference of 0.5 C.C. or more, I n most cases thymol- phthalein, which changes colour at a lower concentration of hydrogen ions than phenolphthalein, gives more accurate results, but it requires a certain amount of alcohol to keep it in solution, and this sometimes precipitates the protein deriva- tives. Whichever indicator be employed, the results must be corrected by those of a blank titration with water, instead of the amino-acid solution, coloured, if necewary, to match the latter by means of an orange or brown dyestuff.The conditions as regards the volumes of the various solutions must be as nearly as possible identical in the two titrations, and the blank titration Berves as a colour standard for the neutral point selected. This must be on the alkalino side, but a further addition of alkali should still produce a further change. Whenever possible, solution of barium hydroxide should he employed, but in cases where this cause8 a precipitate of protein compounds sodium hydroxide must be substituted. For the titration with phenolphthalein a solution of 0.5 gram of the indicator in 50 C.C. of absolute alcohol is diluted with 50 C.C. of water. The formaldehyde solution, which must be freshly prepared, is made by adding 1 C.O. of the phenolphthalein solution to 50 C.C.of commercial formalin, and neutralising to a faint pink wibh $barium hydroxide. TheTHE ANALYST, 21 blank titration is then made 138 follows: A quantity of boiled water equal to the quantity of amino-acid solution to be taken (in most cases 20 c.c.) is mixed with 10 C.C. of the formaldehyde solution, and a quantity of $ barium hydroxide (generally 5 c.c.) equal to half that required by the amino-acid is run in. The liquid is then titrated back with hydrochloric to the pale pink tint, and the distinct rose or the vivid red selected as the standard neutral point is then restored by the additio2 of 1 to 3 drops of the baryta solution. In the case of thymolphthalein, 0.5 gram of the indicator is dissolved in 1 litre of 93 per cent.alcohol. The formaldehyde solution is then prepared by mixing 50 c.c, of commercial formalin with 25 C.C. of absolute alcohol and 5 C.C. of the indicator solution, and the mixture is neutralised with In this case 15 C.C. of the above solution are employed in the titrations, the neutral tint (a bright blue) being established as in the case of the phenolphthalein. The quantity of amino-acid solution used should be equivalent t o about 10 C.C. of the barium hydroxide, and should lie between the limits of 10 C.C. and 30 c.c., the higher concentration giving the best results ; but in any case the quantity of formaldehyde solution should be constant. The amino-acid solution is titrated in the same manner as the blank, without allowing too great a time to elapse between the two titrations.Two amino acids give bad results-proline too low, and tyrosine, on account of its phenolic hydroxyl, too high. Salts of guanidine, creatine, creatine and urea, react as neutral bodies ; ammonium salts react as monobasic acids. In the C&80 of phenylalanine, baryta gives precipitates, and soda must be employed. The author quotes a number of examples of the application of his process for the study of the rate of proteolysis of polypeptides and typical proteins by acids and enzymes. When acid or alkali is added to assist the digestion, it is neutralised by the addition of an equivalent quantity of alkali or acid before titration. The results are expressed in terms of nitrogen, 1 C.C. of barium hydroxide being equivalent to 2.8 mgrns.of nitrogen, J. F. B. barium hydroxide. Titration of' Uric Acid in Presence of Formaldehyde. S. P. L. Sorensen. (Comptes rend. du Lab. de Carlsberg, 1907, 7, 55-57.)-Uric acid may be titrated with sodium hydroxide in presence of phenolphthalein with a fair degree of accuracy, but it is necessary to use a large quantity of water in order to maintain the sodium urate in solution. With barium hydroxide the titration in the ordinary way is almost impossible, owing to the formation of basic precipitates which are hydrolysed slowly. In the presence of formaldehyde, by the method described in the preceding abstract, the titration of uric acid in small quantities of water is readily effected. The uric acid, 0.3 to 0.5 gram, is mixed with 20 C.C. of water and the prescribed quantities of formaldehyde and phenolphthalein, On the addition of a slight excess of sodium hydroxide, the uric acid is rapidly dissolved, and behaves as a monobasic acid when the solution is titrated back with $ hydrochloric acid.barium hydroxide is employed, the uric acid requires ten to fifteen minutes to dissolve, but the titration is equally accurate. Thymolphthaleiu, on account of the insolubility of the barium urate in alcohol, ie not recommended. When J. F. B.22 THE ANALYST. Estimation of Arsenic in Urine. C. R. Sanger and 0. F. Black. ( h u m SOC. Chem. Ind., 1907, 26, 1123-1127.)-The method depends upon the distillation of the arsenic from the urine after acidification with hydrochloric acid, and its estimation by Marsh’s method, or the modification of Gutzeit’s method described on p.28. Two hundred C.C. of the urine are concentrated on the water-bath to about 35 c.c., and introduced into the distillation flask of the apparatus shown in duplicate in the figure. The flask holds 300 c.c., and has a neck 20 cm. in length with a side tubulure 20 cm. long, the out- let of which is connected by means of a rubber stopper with a vertical condenser having an inside tube 60 cm. in length. The end of the con- denser passes through a rubber stopper, over which is slipped a tube 15 cm. in length with a bulb of about 25 C.C. in capacity, the object of which is to prevent any of the distillate being drawn back into the condenser. The end of this tube dips into a flask containing 25 C.C. of con- centrated nitric acid. The concentrated urine in the flask is mixed with 100 C.C. of pure strong hydrochloric acid, and the mixture distilled over a small flame so that about half the liquid passes over in thirty to forty minutes. The distillate, which will contain all the arsenic originally present, is mixed with 25 C.C. of strong nitric acid, evaporated to a small volume, 3 to 5 C.C. of strong sulphuric acid added, and the evaporation continued until all nitric acid has been expelled. Any residual organic matter is destroyed by adding a few drops of nitric acid, and heating the mixture until the sulphuric acid is colourless. The residue is then diluted to about 25 c.c., and the arsenic estimated in an aliquot portion. Even if the arsenic is present in the urine in the form of arsenate, it is c9mpletely converted by the concentrated hydrochloric acid into arsenic trichloride. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9083300019

出版商:RSC    

年代:1908

数据来源: RSC

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22 THE ANALYST. ORGANIC ANALYSIS. General Reaction for the Identification of Multiple Bonds in Un- saturated Compounds of the Aromatic and Aliphatic Series. E. Molinari. (Ber. deut. Chem. Ges., 1907, 40, 4154-4161.)-1~ the aromatic series it is necessary to distinguish between compounds which are definitely unsaturated and contain double bonds in the nucleus, as formulated by Kekulk, and compounds which combine with halogens only by substitution, having a structure more in accordance with Baeyer’s centric formula. I n the aliphatic series it is necessary to distinguishTHE ANALYST. 23 between unsaturated compounds with double bonds of the ethylene type and those with triple bonds of the acetylene type. The test proposed by the author depends on the fact that unsaturated compounds containing double bonds, whether aliphatic or aromatic, combine rapidly with ozone, forming ozonides.Aliphatic compounds con- taining triple bonds do not absorb ozone, but they possess a high iodine absorption value, Aromatic compounds to which Baeyer’s centric structure must be assigned do not absorb ozone. I n applying the test qualitatively, a few decigrams of the substance are dissolved in a few C.C. of a liquid which does not absorb ozone. A stream of ozonised air is passed through the solution, and its absorption or non-absorption is ascertained by potassium iodide and starch paper. I n the case of aliphatic compounds with double bonds, the absorption of ozone may be determined quantitatively by increase of weight. The absorption takes place in the ratio of 1 molecule of ozone (0,) to each double bond.If the iodine absorption value is distinctly greater than its equivalent ozone absorption value, it may be inferred that the substance is a mixture of compounds with double bonds and triple bonds. Amongst the aromatic compounds which absorb ozone are the polyhydric phenols, benzoquinone, phenanthrene, anthracene, naphthalene, quinoline, etc. Benzene and its homologues, phenol, pyrocatechol, anthraquinone, etc., do not absorb more than traces of ozone. J. F. B. Alkaline Saponification of Alkyl Nitrates in Presence of Hydrogen Peroxide. T. Carlson. (Bcr. deut. Chcnz. Ges., 1907, 40, 4191-4194.)-ln a previous paper, Klason and Carlson had shown that alkyl nitrates, on saponification by alcoholic potash, behave partially as if they were nitrites of alkyl peroxides.These peroxides, under the influence of the alcoholic alkali, tend to break down into aldehydes and water, and the aldehydes then undergo resinification and other profound changes. The simultaneous presence of a mercaptan prevents this change, the peroxide being reduced and the normal alcohol regenerated. The production of a peroxide and a nitrite as primary products of alkaline saponification of an alkyl nitrate is the converse of Baeyer and Villiger’s observation that ethyl nitrate is formed by the action of nitrous acid on ethyl peroxide. With the nitrates of monovalent alcohols, the production of nitrite during saponification increases with the molecular weight of the alkyl complex, whether mercaptan be present or not, but the nitrite obtained in presence of inercuptsn is always higher than in its absence.The nitrates of polyvalent alcohols, such as glycerol or cellulose, yield very large pro- portions of nitrite on saponification by alcoholic potash. With these nitrates the alkyl complex is almost entirely destroyed, owing to the action of the alkali on the peroxide first formed. The peroxide, however, may be decomposed in the nascent state by carrying out the saponification by means of alcoholic potash with the addition of hydrogen peroxide. By the interaction of the two peroxides, oxygen is liberated, and the alcohol, glycerol or cellulose is regenerated without destruction. The quantity of oxygen evolved is equivalent to the quantity of nitrite produced.J. F. B. Estimation of Halogens in Organic Substances. James Moir. (Proc. Chm. SOC., 1907, 23, 233.)-The process previously described by the author24 THE ANALYST. (ANALYST, 1906, 31, 420) is now improved by adopting the Volhard method of back titration with standard thiocyanate solution. The contents of the nickel crucible after heating are dissolved and treated with a crystal of bisulphite to reduce manganate. A measured quantity of standard silver solution is added, and the mixture then acidified with nitric acid, heated to 70" C., filtered through a Buchner funnel, using hardened paper, and the residue on the filter extracted with hot dilute nitric acid. The filtrate is cooled t o 40' C., and then titrated with standard thio- cyanate and iron alum.Each C.C. of decinormal silver solution, by difference, is equal to 0.0080 gram of bromine, A. R. T. Estimation of Hydrazine. A. W. Browne and F. F. Shetterlg. (Bey. dezk Chent. Ges., 1907, 40, 3953-3962.)-The usual method of estimating hydrazine is that proposed by Hofmann and Kiispert (ANALYST, 1898, 23, 95), which consists in oxidising the hydrazine in acid solution by means of ammonium metavanadate, ac- cording to the equation : N2H4.H,S0, + 2 0 = N, + 2H20 + H,SO,. The quantity of metavanadate reduced is then determined by titration with permanganate. An alternative method proposed by the same chemists consists in performing the oxida- tion in a current of carbon dioxide, and collecting and measuring the nitrogen evolved in a nitrometer. The authors have found, however, that the reaction does not proceed entirely according to the above equation, but that larger or smaller quantities of hydraeoic acid and ammonia, depending on the conditions, are produced, thus : The error thus introduced in the method of estimation described (Zoc. cit.) amounts to about 4.5 per cent.in the nitrometer method, but only to about 1 per cent. in the permanganate method. The end-point with the permanganate is not very sharp, and consequently a small excess of permanganate has to be added before the end of the titration is certain; this slight excess makes the error of the per- manganate method less than it would otherwise have been. 2N2H, + 2 0 = N,H + NH, + 2H20. J. F. I%. The Reaction of Phloroglucinol-Hydrochloric Acid with Essential Oils.K. Kobert. (Zezt. a n d Chcm., 1907, 46, 711-714.)-1t has been shown previously by Rosenthaler (ANALYST, 1905, 30, 247) that certain essential oils give colorations when treated with vanillin and hydrochloric acid, and the author now describes tho reactions which take place when these oils are mixed with phloroglucinol and hydro- chloric acid. The reagent is prepared by dissolving 1 gram of phloroglucinol in 10 C.C. of alcohol; 1 C.C. of this solution is then mixed with 9 C.C. of concentrated hydrochloric acid. On shaking a few drops of the essential oil with 0.5 C.C. of the reagent, a bright red coloration is obtained in the case of mustard oil, clove oil, pimento oil, dill oil, orange-blossom oil, tarragon oil, basil oil, bay oil, lavender oil, Peru balsam oil, geranium oil, parsley oil, sassafras oil, and the oil from jaborandi leaves.A brownish-red coloration is given by cassia oil, bergamot oil, aniseed oil, eucalyptus oil, mint oil, rosemary oil, and lemon oil. I t appears that the red colora- tion is given only by those essential oils, or their constituents, which contain an ally1 group in their molecule. w. P. s.THE ANALYST. 25 Note on Fucose and the Estimation of Methylpentosans in Natural Products. W. Mayer and B. Tollens. (Journ. Landw., 1907, 55, 261 ; Chem Z e d Rep., 1907, 31, 531.)-Tragaca,nth is not suitable for the preparation of fucose, because the product is contaminated with large quantities of arabinose, but from 19 kilograms of seaweed the authors obtained 70 grams of pure fucose. The osazone melts at 177.5' C.; thus it has the same melting-point as rhodeosazone. Fucose is decomposed by hydrochloric acid more slowly than rhamnose, and for the estimation of the methylfurfural it requires a longer distillation. For this reason the yield of methylfurfural is lower than with rhamnose, since the aldehyde is gradually converted into other products. With 0.05 to 0.1 gram of fucose it is necessary to distil over more than the usual 360 to 400 C.C. before the distillate ceases to give the methylfurfural reaction. A quantity of phloroglucinol equal to that of the fucose taken is added to the distillate, and the liquid is put aside for one and a half to two days until the precipitate has settled. The phloroglucide is collected in a Gooch crucible, washed with 150 C.C.of water, dried in the water-oven for four hours, and weighed in a stoppered bottle. The quantity of fucose is calculated from the formula already given (ANALYST, 1907, 32, 300), or from tables drawn up by the authors. When arabinose is present the phloroglucide consists of a mixture of the furfural and methylfurfural derivatives. These may be separated, after drying and weighing the precipitate, by repeatedly extracting the latter in the crucible with hot alcohol. The meth ylfurfural compound is dissolved, and the insoluble furfural phloroglucide is then dried and weighed. J. F. B. Melting-Point of d-Phenyl-Glucosazone. Frank Tutin. (Proc. Chenz. Soc., 1907, 23, 250.)--The phenyl-osazones obtained from the sugars present in various plants were found in many instances to melt at a temperature considerably higher (up to 219' C.) than the usually accepted melting-point of d-phenyl-glucosaxone-- namely, 205" C.Analyses of these compounds of high melting-point showed them to be osazones of hexoses, and it was at first supposed that they were identical with a-acrosazone (melting-point 217O C.). By careful recrystallisation from pyridine, however, all the osazones were obtained melting between 216" to 218" C. The method adopted was to dissolve the osazone in a small quantity of boiling pyridine, add some hot alcohol and then a little water, and allow the solution to cool. On similarly purifying a specimen of d-phenyl-glucosazone (prepared from dextrose and melting at 205' C.), this also melted-at 217O C., while another specimen of the same compound, carefully prepared with recently distilled phenyl-hydrszine, showed an initial melting- point of 216" C.Thus d-phenyl-glucosazone, when pure, melts at about 217' C., and not at 205' C., as stated by Fischer (Ber., 1884, 17, 579). A. R. T. Colour Reactions of Rosin Spirit. C. Grimaldi. (ChesIL. Zeit., 1907, 31, 1145-1146.)-Rosin spirit, and more particularly that portion of it which boils at a temperature of 170" C., gives an emerald green coloration when heated with hydro- chloric acid and zinc, whilst turpentine, camphor oil, mineral oil, etc., yield yellow or brown colorations. The sample to be tested for rosin epirit is distilled, and the portion26 THE ANALYST. passing over at 170" C. is heated with an equal portion of concentrated hydrochloric acid and a small piece of zinc for five minutes in a boiling water-bath.During the heating the mixture should be shaken frequently. Rosin spirit also gives a yellowish- green coloration with Halphen's test-phenol and bromine vrtpour (ANALYST, 1903, 28, 9)-whilst turpentine is not coloured at all, and rosin oil, camphor oil, mineral oil, etc., give violet or red colorations. w. P. s. Vulcanisation Tests with Plantation Rubbers. C. Beadle and H. P. Stevens. (Chem. News, 1907, 96, 235-236,)-A determination of the specific gravity of the vulcanised samples described in a previous communication (ANALYST, 1907, 32,337) showed that this value tended to increase on keeping, especially in the case of fully cured rubber. Over-cured samples, whether of plantation or (' hard-cure " Para rubber, showed a relatively high specific gravity after being kept for some months, and, as a rule, a decrease in tensile strength was attended by a decided increase in the specific gravity.In the case of freshly vulcanised samples of different types of rubber, some of which were under-cured and others over-cured, but small differences were observed in the specific gravities, although different methods of preparation were used. As a rule this value is not lower than 0.94, and seldom reaches 0.96, unless the rubber has been over-cured and kept for some months, in which case it may reach 0.913. Samples tested for tensile strength show a lower specific gravity than the untreated rubber if examined immediately after the test, but recover their former value when kept for some time.A specimen of the best Ceylon biscuit rubber gave the following results on analysis : Moisture, 0-5 ; albuminoids, 0.1 ; resin, 2.8 ; ash, 0.4 ; and caoutchouc (by difference), 96.2 per cent. When vulcanised under various conditions the average tensile strength of the product differed but little from the results given by "hard- cure " Para rubber (Zoc. cit.). C. A. M. Poison Sumach. A. B. Stevens and L. E. Warren. (Amer. Journ. Pllzarm., 1907, 79, 499-522.)-The juice of the poison sumach (Rhus vernis), which grows in swamps in North America, has varnish-forming properties resembling those of the juice from the Japanese lac-tree (R. vernicifera), and has the same poisonous action upon the skin. The fresh juice examined by the authors was slightly acid, and had a specific gravity of 0.9976 at 20" C.I t contained from 9.9 to 18.9 per cent. of water, 76 to 84 per cent. of crude resins " soluble in alcohol, and 5.2 to 8 per cent. of a gumlike substance insoluble in alcohol, but soluble in water to the extent of 1.7 to 2.6 per cent. This gum had a strong enzymic action, turning guaiacum tincture blue, and causing the separated resins to become black in the same way as the fresh juice. The crude resins contained a poisonous oily substance to which the odour of the juice was attributed. The fruit of the tree contained a large amount of a greenish-white fat with a peculiar odour and a taste like that of tallow. It gave the following values: Specific gravity at 25'/25O C., 0.9749 ; melting-point, 38' to 39" C.; saponification value, 236.3 ; and iodine value, 13-1. The residue left after recrystallisation from petroleum spirit and from alcohol had an elementary composition agreeing with that of myristin. The The separated resins were also found to be poisonous.THE ANALYST. 27 fruit contained no starch, alkaloids, or glucosides, but the residues left after extraction of the ftlt were rich in nitrogen. No poisonous constituent was found in the ripe fruit. C. A. &I. The Titration of Tannin by Iodine : An Answer to Cormimbamfs Note. F. Jean. ( A m . Clzirn. a n d , 1907, 12, 426-427 ; compare ANALYST, 1907, 32,426.)- The author claims that his method gives exact results when properly carried out, working with a solution saturated in the cold with sodiuni bicarbonate. The iodine solution must be separately standardised against pure tannic acid and against gallic acid, as these bodies absorb different quantities of iodine. A.G. L. The Estimation of Tartaric Acid in the Presence of Malic and Succinic Acids. J. v. Ferentzy. (Chem. h i t . , 1907, 31, 1118.)-The method is based upon the insolubility of basic magnesium tartrate in a mixture, in equal parts, of alcohol and water, and the ready solubility of the corresponding salts of malic and succinic acids in the same solvent, The solution containing the three acids is concentrated to a small volume, and' sufficient alcohol added to bring the alcoholic strength to 50 per cent. I t is next treated with magnesia, mixture and 10 C.C. of ammonia solution, the alcoholic strength again brought to 50 per cent., and the whole thoroughly shaken and allowed to stand for twelve hours.The crystalline preci- pitate is then collected, washed with 50 per cent, alcohol, dried, ignited, and weighed. The amount of magnesium oxide multiplied by the factor 1.875 gives the corresponding amount of tartaric acid. C. A. If. The Examination of Turpentine Oil. W. Flath. (Farben Zeit., 1907, 13, 78; Clzem. Z e d . Rep., 1907, 31, 564.)-The specific gravity of pure turpentine oil usually lies between 0.860 and 0.870 at 15' C., but may be somewhat higher or lower. If the specific gravity of a pure oil were particularly high, the value might still remain normal after the addition of 10 per cent. of heavy petroleum, which would also not be recognissble by the odour. Even larger quantities of heavy petroleum may be mixed with refined tar oil without appreciably affecting the specific gravity. According to the author, pure turpentine oil, mixed with an equal volume of freshly distilled aniline, gives a clear solution, whereas in the presence of petroleum the liquid remains turbid. The substitution of American wood turpentine oil for Russian or Swedish turpentine oil may be detected by shaking 2 C.C. of the sample with 1 C.C. of concentrated sulphurdioxide solution. In the case of Russian or Swedish turpentine oil a bright yellow or greenish coloration is produced, whilst with pure American or French turpentine oil the liquid remains white and turbid. The addition of 5 or 10 per cent. of a Russian oil causes a perceptible greenish coloration to appear. This reaction is given by all turpentine oils obtained from wood, and is due to an apparently inseparable constituent of the oil. C. A. N.

ISSN:0003-2654    

DOI:10.1039/AN9083300022

出版商:RSC    

年代:1908

数据来源: RSC

摘要:

28 THE ANALYSTo INORGANIC ANALYSIS. Quantitative Estimation of Arsenic by the Gutzeit Method. C. R. Sanger and 0. F. Black. ( J o z L ~ . SOC. Chem. Ind., 1907,26,1115-1123.)-1f the arsenuretted hydrogen be made to act along the surface of the sensitised paper instead of against it, there is no difficulty in differentiating between the stains caused by various amounts of the gas. Cold-pressed Whatman drawing-paper gives better results than filter- paper. It should be cut into strips of 4 mm. in width, which are sensitised by being drawn repeatedly through a 5 per cent. solution of recrystallised mercuric chloride, then dried on a horizontal rack of glass rods, cut into lengths of 7 cm., and kept in the dark in a bottle containing calcium chloride, covered with a layer of cotton-wool until required for use.The apparatus consists of a 30-C.C. bottle, closed by a pure rubber cork, through which is passed a small thistle funnel, reaching nearly to the bottom, and also an outlet tube for the gas. This tube is bent first at a right angle and then back again in the form of a c, and is connected by means of a rubber stopper with a bulb tube about 12 mm. in diameter, terminating in a longer tube with au internal diameter slightly over 4 mm. The bulb of the tube is loosely filled with dry cotton-wool, and a strip of the sensitised paper slipped into the open end of the tube to a definite digtance. The bottle is charged with 3 grams of arsenic- free zinc, 15 C.C. of pure dilute hydrochloric acid (1 : 6) introduced through the funnel, and the hydrogen allowed to pass over the paper for at least ten minutes.The solution (not exceeding 15 c.c.) of the substance under examination is now intro- duced, and in the presence of arsenic the coloured deposit appears on the paper in a few minutes, and reaches its maximum intensity within thirty minutes. The amount of arsenic may then be found by comparison with standard bands prepared from known quantities of arsenic. A set of standards may be kept without much alteration for some months, if sealed up in glass tubes about 5 mm. in diameter, containing at the end a little phosphorus psiitoxide covered with dry cotton-wool. If the colour bands be developed by treatment with hydrochloric acid (I : I), they are rendered some- what more permanent, whilst development with N-ammonia solutions changes them into black stains, which are much more permanent than the originals.They should, however, be sealed up in glass tubes containing a little powdered fresh quicklime. Sfter ten or twelve estimations, the atmosphere in the deposition tube becomes too moist, and it is necessary to replace the cotton-wool in the bulb tube; otherwise the bands on the paper will be too short. Hydrogen sulphide may be eliminated by inserting a strip of lead acetate paper into the deposition tube. Small amounts of antimony do not prevent the detection of arsenic, but may inter- fere with its estimation. In the case of arsenates, the slower reduction to arsenuretted hydrogen causes the bands on the paper to be smaller than would result in the same time from an equivalent quantity of arsenious acid.An approximate valuation may be made in such cases by comparing the bands with standards prepared from known quantities of arsenic acid or by multiplying the readings of the ordinary standard bands by 2 or 2.5. For more accurate work, however, the solution containing an arsenate (or after oxidation with nitric acid) should be treated with sulphur dioxide solution in sufficient quantity to reduce the arsenate to arsenite, and the excess of sulphurTHE ANALYST. 29 dioxide expelled by partial evaporation of the liquid, care being taken not to carry the evaporation so far as to cause loss of arsenic when chlorides are present. The method is said to be capable of detecting is$aa mgm. to && mgm. of arsenic, but i+GG mgm.is suggested as a working limit. C. A. M. Reduction of Arsenic Trisulphide and Pentasulphide to Arsenic Di- sulphide. R. Ehrenfeld. (Ber. dezct. Chenz. Ges., 1907, 40, 3962-3965.) .- I t sometimes happens that in following out the ordinary routine of qualitative analysis, antimony instead of arsenic is found when tin is also present in the mixture. When the sulphides of the tin group are digested with ammonium carbonate, and the filtrate is acidified, tbe arsenic appears in the form of an orange-red precipitate instead of a yellow one. I t is now proved that this orange precipitate is arsenic disulphide (As$,) which may readily be prepared by heating either the trisulphide or the pentasulphide with a solution of stannous chloride in hydrochloric acid.J. F. 13. Note on the Volumetric Estimation of Bismuth. R. Ehrenfeld. (Zeit. unal. Chenz., 1907, 46,710-711.)-The author has endeavoured to render the phosphate method for the estimation of bismuth volumetric (C'. ANALYST, 1906, 31, 54) ; the bismuth solution, containing a slight excess of nitric acid, was precipitated with a measured excess of sodium phosphate solution, and the excess of the latter titrated back with uranium acetate after the addition of sodium acetate, but the difficulty of observing the end-point of the titration caused the results to be untrustworthy. The quantities found varied from - 9 to + 25 per cent. of the amounts of bismuth trioxide taken. w. P. s. The Constants and Variables of the Parr Calorimeter. S. W. Parr. (Jozmz. Amer. Chem.SOC., 1907,29, 1606-1622.)-The author discusses the accuracy of the results given by his calorimeter (ANALYST, 1901,26, 52 ; 1907,32, 62). He shows that with proper care the results obtained are within 1, or at most 2 per cent. of those given by the Mahler-Attwater bomb. In cases where unburnt carbon is left, this should be filtered off, weighed, and taken into account. He finds that the empirical factor, 73 per cent., by which the results must be multiplied, to be correct for both carbon and hydrogen, and to agree well with the theoretical heat of formation of sodium peroxide. As accelerator, he prefers potassium chlorate ; if 0.5 gram of this is used, 0.040" C. must be deducted from the observed rise of temperature, whilst the correction is 0 . 1 0 8 O for 1 gram of the reagent.A mixture of 2 parts of potassium persulphate with 1 of ammonium persulphate rnrty also be used; the correction amounts to 0.197' per 0.5 gram. Using 0.5 gram of the fuel, the other corrections which must be made are : 0.006" for every 1 per cent. of sulphur; 0.001" for every 1 per cent. of silicious ash ; 0.0033" for every 1 per cent. of combined water, amounting to about 0.033" for bituminous coals, 0.066" for black lignites, and 0.111" for brown lignites; and 0*008" for the ignition wire. The author mentions that '' pure " naphthalene generally contains appreciable quantities of sulphur. A. G. L.30 THE ANALYST, Estimation of Carbon Monoxide in Atmospheric Air. J. L. R. Morgan and J. E. McWhorter. (Joz~m. Amer. Chem. SOC., 1907, 29, 1589-1592.)-1n the estimation of carbon monoxide by passing it over heated iodine pentoxide, the authors find that traces of animal fat, such a8 might be derived from the lubricant used with glass stoppers, react violently with the pentoxide at 100" C., or even 16ss.Hence this reagent should be contained in glass tubes, the endsof which are drawn out after filling. The authors work at a temperature of 150" C., and pass the iodine and carbon dioxide, products of the reaction between iodine pentoxide and carbon monoxide, first through potassium iodide solution, and then through barium hydroxide solution. A check is obtained on the results by titrating both the iodine obtained and the residual barium hydroxide. Moreover, by passing the air through a barium hydroxide tube before it enters the purifying chain leading to the iodine pentoside tube, the carbon dioxide in the air may be determined on the same sample.A. G. L. Adsorption of Iodine by Carbon. Oliver C. M. Davis. (Tmns. Chem. SOC., 1907, 91, 1666.)-The adsorption of iodine, dissolved in various organic solvents, by means of animal, sugar, and cocoa-nut charcoal, has been definitely proved to consist of a surface condensation and a diffusion into the interior of the carbon, since the adsorption is rapid a t first until a "surface equilibrium" is produced, and then proceeds slowly for lengthened periods. The effect of temperature is small, but the time allowed has a marked influence on the adsorption. The adsorption values of animal- and sugar-carbon are approximately equal, and mainly due to surface condensation, while thah of cocoa-nut carbon is much smaller, and due chiefly to diffusion into the interior. A.R. T. Two Volumetric Methods for the Estimation of Chromium. A. W. Gregory and J. McCallum. (Jo?im. C l m t . SOC., 1907, 91, 1846-1849.)-1n the absence of manganese, 20 C.C. of a 1 per cent. solution of silver nitrate and 10 grams of ammonium persulphate are added to the nitric acid solution of chromium. The liquid is then boiled for five minutes, when a few C.C. of a dilute solution of man- ganese sulphate are added. If any persulphate remains undecomposed, a pink colour will be produced, which is just destroyed by the addition of hydrogen peroxide, drop by drop. After once more heating the liquid to boiling, it is cooled and titrated with ferrous sulphate and standard potassium bichromate in the usual manner.If manganese is present, the nitric acid solution is boiled, its before, with silver nitrate and ammonium persulphate. A quantit'y of ammonium chloride is then added sufficient to precipitate nearly all the silver as chloride. On boiling again, the permanganic acid is decomposed with formation of the hydrated peroxide. After making the liquid up to a definite volume, this is filtered off on an asbestos filter, and chromium determined in half the filtrate as above. A. G. L. Rapid Analysis by Electrolysis without Rotating Electrodes. F. C I Frary. (Jourw. A?izer. Clzem. SOC., 1907, 29, 1592 -1596.)-Electrolysis can be rapidly carried out with stationary electrodes by circulating the liquid.This isTHE ANALYST. 31 effected by surrounding it by a magnetic field. The author describes two forms of apparatus, both of which can be obtained from the Vereinigte Fabriken fur Labora- toriumsbedarf, Berlin. I n the first, 500 turns of 1.5 mm. copper wire are wound on a copper cylinder, 6 cm. in diameter and 11 cm. high, with sheet-iron flanges. A hollow iron cylinder, 4 cm. high, with walls 1 cm. thick, stands in the lower part of the copper cylinder. The beaker in which the electrolysis is carried out is placed inside the solenoid, on the top of the iron cylinder. A cylinder of platinum gauze is preferably used as cathode ; it should fit the beaker fairly closely. The anode may be a spiral wire in the centre of the beaker. The solenoid will take a current of up to 5 ampBres, and is generally connected in series with the electrodes.As heat is developed, the beaker may be water-cooled if necessary. The bottom of the beaker is given an annular form and rests on the solenoid, the iron core of which extends upwards into the central space. The beaker is surrounded by an iron ring acting as the other pole of the electro-magnet. The solenoid is enclosed in an iron mantle 2 mm. thick. The second form of apparatus is designed for use with a mercury cathode. A. G. L. The Ignition Temperatures of Gaseous Mixtures. K. G. Falk. (Jou7-n. Amer. Chem. Soc., 1907, 29, 1536-1557.)-The ignition temperatures of a number of gaseous mixtures were determined by suddenly compressing the gases contained in steel cylinders until explosion occurred.The compression was effected by droppiug a weight on a piston fitting the cylinder, and was so rapid as to be adiabatic ; conse- quently, the temperature reached could be calculated from the initial and final pressures, To eliminate various errors, four pieces of apparatus, holding different quantities of gas, were used, but the results obtained agreed very closely with each other. The effect of the pressure on the ignition temperature is disregarded, but should be small. The following table shows some of the results obtained : Mixture. Ignitioii Teniperature. I I Mixture. Igii it ion Tern pera ture. 878' C. 813' C. 787" c. 803" C. 844" C. 6CO + 0, 4CO + 0, H, + 0, + CO 2 c o + 0, co + 0, 994" c. 901" c. 874" C. 904" C. 812" c.The ignition temperature of mixtures of hydrogen, oxygen, and nitrogen can be calculrtted from the (empirical) formula : T = T, + 30n (a), where T' is the ignition temperature as given by the abom table, and n equals the volume of inert gas divided by the volume of H, or of 0,, whichever is the smaller. The calculated results agree well with those observed. Similarly, the ignition temperature of mixtures of carbon monoxide, oxygen, and nitrogen can be found from the formula : T=T,+80d ( b ) , where T, is the ignition temperature as shown by the table, and n'34 THE ANALYST. equals the volume of inert gas divided by the volume of carbon monoxide. For mixtures of hydrogen, carbon monoxide, and oxygen, the ignition temperatures should be calculated aecording to both the above equations, assuming in one case that hydrogen is an inert gas, in the other that carbon monoxide is inert.The lower of the two results found will approximate closely to the observed ignition temperature. The author also shows the reaction between hydrogen and oxygen to be bi- molecular, hydrogen peroxide probably being the first product, and that between carbon monoxide and oxygen to be trimolecular. With excess of hydrogen or of carbon monoxide present, the reactions do not follow any simple law of chemical kinetics. The velocity coefficient per 10" C. rise in temperature is calculated to be 1.31 at 800" C. and 1.13 at 900" C. for the reaction between hydrogen and oxygen, and 1-24 at 900n C. and 1-14 at 1000" C. for that between carbon monoxide and oxygen.A. G. L. The Occurrence of Helium in Natural Gas and the Composition of Natural Gas. H. P. Cady and D. F. McFarland. (Joz~rn. Amer. Chem. SOC., 1907, 29, 1523-1536.)-Analysis of forty-one samples of natural gas from various parts of the United States showed helium to be present in every case except one. l t s quantity varied from a trace up to 1.84 per cent., and tends to increase, although not directly, with that of the nitrogen. It was found possible to trace lines of "iso- helium " and '' iso-paraffin " content across the State of Kansas, these lines following approximately the lines of outcrop of the various geological strata. The helium was isolated by absorbing the other gases not liquefied by liquid air in cooled cocoanut charcoal, according to Demar's method.The authors find that this absorbs hydrogen rather freely, neon much less than hydrogen, and helium practically not at all. Some typical analyses are given in the following table : Locality. Dexter, Kansas ... Garnett, Kansas.. . Arkansas City, Kansas ... Blackwell, Okln.. . . Sheffield, Mo. ... Kansas City, Mo.. . Butler, Ohio ... Marion, Ind. ... Iforgantown, W. Va. ... ... Jennings, La. ... Los Angeles, Cal. c G 0 tc 3 0.20 trace 0.20 0.20 0.10 0.05 - - - 1.81 2.86 - 0 20 0.10 0.83 0.60 0.73 0.24 1.80 6.68 __ - - 0.16 0.10 0-61 0.50 1 90 0.40 0.86 0.65 0.80 0-20 14.85 94.30 81.10 83.40 92.90 87.20 70.00 77-40 88-10 88.40 83.70 0.41 0.36 11-95 10.31 7.03 16.75 14.18 7.37 1-03 - -_ E 4 .r( 3 2 1.84 0.37 0.159 0.16 0.04 1 0.013 0.15 0.167 0.09 trace - 88.70 4.61 6.39 5.19 5.43 3.65 12-38 6.66 3.60 5-76 6.31THE ANALYST.33 The last two samples contained air. I n a sample from Bartlesville, Ind. Terr., helium was found to be present, but its amount was not determined. A. G. L. Volumetric Estimation of Lead. H. Bollenbaeh. (Zeit. axal. Clze??~., 1907, 46, 582-588.)-1n the method proposed the lead solution is titrated with potassium permanganate. The lead solution is first treated with sodium hydroxide until the precipitate which forms is redissolved, and the whole is then diluted t o a known volume. Fifty C.C. of this solution are run slowly from a pipette into a measured volume (which must be an excess) of standard permanganate solution placed pre- viously, together with about 400 C.C. of hot water and 5 C.C.of 8 per cent. sodium hydroxide solution, in a 500-C.C. flask. During the addition of the lead solution the mixture is well agitated. The excess of permanganate is then titrated back by means of The titration is complete when the violet coloration disappears. lead nitrate solution. The reaction proceeds according to the equation : GPb(NO,), + 2KMn0, + 12NaOH = 2Mn0, + 3Pb,0, + 2KOH + 12NaN0, + 5H&. The permanganate solution is standardised on & lead nitrate solution. The results are not influenced by the presence of chlorides, bromides, or sulphates, but iodides, sulphides, acetates, nitrites, arsenic and mercurous salts, and other substances which reduce permanganate, must not be present. w. P. s. Volumetric Estimation of Magnesium. L. Rosenthaler.(Zeit. a d . Chem., 1907, 46, 714-716.)-The magnesium is precipitated in ammoniacal solution by the addition of standard potassium hydrogen araenate solution, and the excess of the latter is titrated after the removal of the magnesium ammonium arsenate by filtration. The magnesium solution is placed in a graduated flask, a measured excess of potassium hydrogen arsenate (KH,AsO,) solution ie added, and the mixture is diluted to a known volume with 10 per cent. ammonia. After three hours, the solu- tion is poured through a dry filter, and a definite quantity (as large as possible) of the filtrate is evaporated to dryness on the water-bath. The residue is taken up with the least possible quantity of water, the solution is poured into a stoppered flask, and the basin is rinsed with a cold mixture of equal parts of sulphuric acid and water, or with concentrated hydrochloric acid, the rinsings being also added to the flask.A concentrated potassium iodide solution is now added to the acid solution ; usually a precipitate forms (if not, a little more acid is added), and is dissolved by the addition of just sufficient water. After standing for fifteen minutes, the liberated iodine is titrated with thiosulphate solution (cf. ANALYST, 1906, 31, 416). The potassium hydrogen arsenate solution should contain about 9 grams of the salt per litre, and it is standardised on the thiosulphate solution. The quantity of arsenate precipitated by the magnesium is thus found in terms of thiosulphate solution, and the magnesium is calculated from the latter.Each C.C. of Fi thiosulphate solution is equivalent to 0*002018 gram of magnesia, (MgO). The proportion of the quantity of filtrate taken to the total volume is, of coume, taken into account in the calculation. w. P. s.34 THE ANALYST. Modiflcations for Shortening Volhard's Method for the Estimation of Manganese. E. W. Mayer. (Zeits. nngew. Chem., 1907, 20, 1980-1981.)-The method originally described by Volhard for the estimation of manganese in iron and steel involves a considerable expenditure of time and labour, and various proposals have been made with a view to its simplification. The author has investigated the four modified methods described below, comparing the results obtained with those yielded by the original Volhard method. 1. One gram of ferro-manganese, 4 grams of pig-iron, or 8 grams of steel, are dissolved in strong hydrochloric acid and oxidised by cautiously adding potassium chlorate. The liquid is boiled until it no longer smells of chlorine, and is transferred with water into B litre measuring flask.The iron is precipitated by means of zinc oxide paste, water is added up to the mark, and the liquid is mixed and filtered through a dry filter. An aliquot portion of the filtrate is then titrated with perman- ganate without the addition of nitric acid. 2. The hydrochloric acid solution of the metal is oxidised with concentrated nitric acid instead-of with potassium chlorate, and the procedure described under 1 is followed. 3. The metal is dissolved in nitric acid (specific gravity 1.2); the solution is concentrated to a small bulk, then diluted and treated as before.4. The metal is dissolved in nitric acid (specific gravity 1.2), and a few drops of strong hydrochloric acid are added to increase the oxidising effect ; further treatment a8 before. The results showed that none of the above modifications is more accurate than the others, but that all are available for technical analyses. Noteworthy differences between these methods and the original Volhard's method only occur in the case of alloys rich in manganese. This is due to the incomplete oxidation of organic compounds by the wet methods, and the error may be allowed for by deducting 0.2 to 0.3 C.C. of i! permanganate from the quantity consumed. The author prefers to dissolve the metal in nitric acid because this acid is more rapid in its action than hydrochloric acid.The chlorate method is not so convenient because it is necessary to remove the excess of chlorine before proceeding with the analysis. J. F. B. Estimation of Mercury by Reduction of Mercurie to Mercurous Chloride by Hydrogen Peroxide. A. Kolb and A. Feldhofen. (Zeits. angezo. Chenz., 1907, 20, 1977-1980.)-1t was observed some years ago that mercuric salts under suitable conditions may be reduced by means of hydrogen peroxide to mercurous chloride or metallic mercury, and the authors have now worked out a method for the estimation of mercury by weighing the mercurous chloride produced, or prefer- ably by titrating it with iodine. The reduction to mercurous chloride only takes place in neutral or slightly acid- solutions ; in alkaline solutions metallic mercury is formed.In the reduction of mercuric chloride hydrochloric acid is set free, and a salt of a weak organic acid must be added to remove it, for which purpose ammonium tartrate is most suitable, For the estimation, 25 C.C. of mercuric chloride solution (5 grams per litre) are mixed with 10 C.C. of 2N hydrochloric acid and 25 C.C. of ELTHE ANALYST 35 10 per cent. solution of tartaric acid. The liquid is then neutralised with strong ammonia (3.8 c.c.), and again made faintly acid with tartaric acid. The liquid is warmed, and 10 C.C. of 3 per cent. hydrogen peroxide are added. Further quantities of the peroxide are added, 5 C.C. at a time, at intervals until, after about forty-five minutes, 25 to 30 C.C.have been used. The liquid is then left for fifteen minutes on the water-bath, and diluted with an equal volume of water. After settling, the mercurous chloride is collected on a tared filter and weighed after drying, or else the moist filter and precipitate are placed in a bottle with excess of iodine and 10 C.C. of 10 per cent. potassium iodide, and the excess of iodine is titrated back with thiosulphate. Mercuric chloride may be estimated in the presence of arsenic, antimony, tin, cadmium, and bismuth, but not in presence of lead or copper. The presence of nitrates, as in the case of bismuth nitrate, exerts a retarding influence on the reduction ; double the usual quantity of peroxide must be used, and the reduction is only complete after about three hours.J. F. B. The Volumetric Estimation of Potassium as Cobaltinitrite. W. A. Drushel. (Zcit. anorg. Chenz. , 1907, 56, 223-229.)-The solution of the potassium salt, which must not contain more than 0.2 gram of potassium oxide and must be free from ammonium salts, is treated with a fairly large excess of an acetic acid solution of sodium cobaltinitrite, and evaporated to a paste-like consistency on the water-bath. The residue is cooled, treated with 50 to 100 C.C. of cold water to dissolve the excess of sodium cobaltinitrite, allowed to stand, and the precipitate collected on an asbestos filter, and washed with cold water. I t is then introduced, together with the asbestos, into a known quantity of nearly boiling & potassium permanganate solution, and stirred for five or six minutes until oxidation is complete. From 5 to 25 C.C. of sulphuric acid (1 : 7) are then added, and the solution stirred and allowed to stand for some minutes, after which a measured excess of N-oxalic acid solution, containing 50 C.C. of concentrated sulphuric acid, is introduced, and the temperature maintained at a little below the boiling-point until the manganese hydroxide has completely separated. The liquid is then titrated back with perman- ganate solution, and the quantity of potassium calculated by multiplying by the factor 1-09 , the oxygen value of the permanganate consumed by the original solution. I n applying the method to fertilisers, 10 grams of the sample are boiled for thirty minutes with 300 C.C. of water, and then made slightly alkaline with ammonia, and treated with suf3icient ammonium oxalate to precipitate all the calcium. The contents of the flask are next made up to 500 c.c., thoroughly shaken and filtered, 50 C.C. of the filtrate evaporated to 25 c.c., and the evaporation completed after the addition of 1 C.C. of sulphuric acid (1 : 1). The residue is cautiously ignited, the potassium sulphate dissolved in hot water, and the potassium estimated as above described. The method is more rapid than the platinum chloride method, or the cobalti-nitrite method of Adie and Wood (Jounz. Chern. SOC., 77, 1076), and, unlike the latter, does not require the use of a potassium solution of definite concentration. C. A. If.

ISSN:0003-2654    

DOI:10.1039/AN9083300028

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年代:1908

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36 THE ANALYST. APPARATUS, ETC. Apparatus for absorbing Acid Vapours given off during the Assay of Gold, Silver, etc. Dard. (Anu. Chiin. anal., 1907, 12, 425-42G.)-The apparatus, which is to be placed in the chimney through which the acid vapours pass, consists of 8, lead-lined box of hard wood having a perforated bottorri and filled with pieces of marble. The lead is turned over, and dips into a gutter made around the chimney; the gutter contains water and forms a water-seal, forcing the gases to pass through the box, where they are absorbed by the pieces of marble. A. G. L, f f i by the-use of this mixture, The oven is heated by a burner in the usual way ; when the alcoholic mixture boils, the vapours passing up the tube c (Fig. 2) are condensed in a condenser fitted to the top of the tube a, and fall back into this tube.During this time the tap d is turned so that the condensed liquid does not return to the oven (see Fig. l), but is conducted When sufficiant condensed liquid 9 FIG. 1. FIG. 2. through the opening h to avessel outside the oveu. 3---+- -11 quently, a wide range of temperature may be attained Apparatus for obtaining Constant Temper- atures in Drying Ovens. J. Habermann. (Zeit. aizal. Clicin., 1907, 46, 574-578.)--The apparatus is constructed of glass, and has the foriii shown in the figures. It is fitted, by means of the cork 9, into an opening at the top of the drying oven. The jacket of the latter is filled with a mixture of two liquids; in an illustration given a mixture of amyl and ethyl alcohols is employed.Amy1 alcohol, mixed with 1 per cent. of alcohol, boils at 120" C. ; with 2 per cent., at 100" C. ; and with 10 per cent., at 84" C. ; conse- has been run off to cause the mixture in the jacket to give the required temperature to the oven (as is ascertained by a thermometer inserted through another opening in the top of the oven), the tap is turned so that vapours condensing subsequently are returned through the tube b to the jacket of the oven. w. P. s. Collodion Membranes. S. L. Bigelow and A. Gemberling. ( JOZLIYZ. Amer. Cheiiz. Soc., 1907, 29, 1576-1589.)-Collodion membranes for dialysis may be easily made by NOVY'S method. A hole 1 or 2 mm. in diameter is blown in the bottom of a glass tube. This hole is then closed by touching it repeatedly with a cork carrying some collodion, but without allowing any of the latter to enter the tube.The tube is next coated with collodion by rotating it whilst just touching the surface of a collodion solution. As soon as the coating has set, and does not stick to the finger, the tube is plunged into water, and water is poured into the interior. The proper moment for this immersion is important, but is soon learnt by experience. TheTHE ANALYST- 37 membrane obtained should neither be too brittle nor adhere to the glass too firmly. Experiments made with sacs prepared in this way showed that collodion membranes B dialyse more quickly than parchment paper, but not so quickly as gold- beater's skin. At constant temperature, the quantity of water passing through collodion membranes is nearly a linear function of the pressure ; at 25" C.a change of 1 mm. in pressure causes a change equal to about 0.6 per cent. of the quantity of water passing with a pressure of 150 mni. With constant pressure, the quantity of water passing is not a linear function of the temperature, but an increase of 20" to 30" C. approxi- mately doubles the rate of flow, The membranes last from one to three months. A. G. L. Simple Gas Generator for Analytical Operations, James McC, Sanders. (Proc. Chcm, SOC., 1907, 23, 232.)-This apparatus consists of a glass tube open at one end, B (see figure), and having a tube of very small bore fused into the other end, C. For the pre- paration of sulphuretted hydrogen, for example, the ferrous sulphide is placed in the space A of the tube, a little dilute acid run in, and the mouth B of the tube closed by the finger, when the gas escapes at C through the fine tube.The apparatus may thus be introduced into a test-tube or other vessel, and employed as a stirrer at the same time. I n operations necessitating the heating of the apparatus it is allowed to touch the bottom of the vessel in which it is placed, and the heat then applied to the outer vessel. For quantitative work a larger form of appa- ratus is used, and the mouth of the tube closed with a cork. A. R. T. Apparatus for Use in Testing Sub- stances for Phosphorus. J. Habermann. (Zeit. a?inl. Chem., 1907, 46, 580-581.) - Nitecherlich's process for the detection of phosphorus in suspected cases of poisoning has the disadvantage that the distillation frequently produces an extremely disagreeable odour. To avoid the latter, the author has devised the piece of apparatus shown in the illustration. The distillation flask is attached to the tube c, the condensed vapours fall from the condenser b into the flask C, whilst volatile compounds distilling over, pass from the flask C through the tube j into the device g, whence they are carried away with the waste water from the condenser. w. P. s.

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DOI:10.1039/AN9083300036

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年代:1908

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38 THE ANALYST. STATEMENT AS TO LICENCES FOR STILLS. PREPARED BY THE REGISTRAI~ OF THE INSTITUTE OF CHEMISTRY. UNDER an Act entitled ‘‘ An Act to prevent the Use of Stills by Unlicensed Persons ” (9 and 10 Vict., cap. 90, 1846), an excise duty of 10s. is imposed on every person, not being a licensed distiller, rectifier, compounder of spirits, or vinegar-maker, keeping or using a still or retort for carrying on the trade of a chemist or other business requiring the use of a still. The duty is payable yearly, and the iicence, which expires on July 5 in each year, must be renewed so long as the still or retort is kept or used. Any infraction of any of the provisions enacted involves liability to a penalty of 230 and the forfeiture of the still, still-head, worm, or retort, in respect of which the oiTence is committed.The premises of any licensee may be entered by any officer of Inland Revenue at any time for the purpose of examining stills kept or used by such licensee; but if the officer enters the premises between the hours of eleven at night and five in the morning, he must be accompanied by a constable or other lawful peace officer (24 and 25 Vict., cap. 91). The Commissioners of Inland Revenue, who are entrusted with the management of the duty imposed by the Act, are empowered to grant exemptions from duty in the case of stills kept or used for experiments in chemistry, or for the manufacture of articles other than spirits or spirit mixtures. Manufacturers of coal-gas do not require a licence for the use of the ordinary retort, and a still used for the distillation oE tar or tar products is exempt, provided that no spirit mixture is used or produced on the premises, and that the name of the person keeping the still is registered by the proper officer.In these cases, however, the oficial right of entry to the premises is not affected, and care is taken to prevent any indulgence being abused. In consequence of representations made in 1893 by the Council of the Institute of Chemistry, the Board of Inland Revenue allow professors and teachers of chemistry, or analytical chemists who carry on no business involving the manufacture of any article for sale from, or containing spirit, to use a still or stills in the bona-jidc exercise of their profession without taking out a licence. By an Order of the Board, dated June 26,1893, works coming within the Alkali, etc., Works Regulations Act, 1881, do not require to be licensed provided a certificate of registration has been obtained from the Local Government Board, in accordance with the provisions of that Act.The Revenue Act, 1850, contains a clause empower- ing the Commissioners to suspend or revoke a licence to use a still or retort should the licensee be convicted of any offence relating to methylated spirit. What constitutes a, “still” within the meaning of the Act has not been specifically defined, but any apparatus capable of being used for the distillation of liquids is liable to licence duty, and the keeping of a still without licence is an offence, whether it is kept for use or for sale. Persons who desire to obtain exemption must make application to the Board of Inland Revenue; and if the application be made through the local supervisor of Inland Revenue, less time is generally occupied than if the communication is sent in the first place to Somerset House.THE ANALYST.39 The following excerpts from the Proceedings of the Institute of Chemistry will explain the position of. professional chemists in this matter : From the Proceedings, Part II., 1892. “The following letter, in reference to the use of stills, has been received in answer to a memorandum drawn up by Mr. M. Carteighe, who had an interview with the officials of the Excise, in accordance with the request of the Council of the Institute : (‘ ISLATI) REVENUE, ‘‘ ‘ SOJCEI:~ET HWSE, LOSDON, W.C., “ ‘ A?l{)ZGSt 2, 1892.( ( DEAR SIR, ( ( Having laid before the Board of Inland Revenue your letter of July 28, I am directed, in reply, to acquaint you, for the information of the Council of the Institute of Chemistry, that the Board have no desire to extend the obligation to take out a licence to analytical chemists using stills solely for purposes of distilling water. If an analytical chemist called upon to take out a licence by one of the Board’s officers will submit his case to the Board, they will be prepared to give it careful consideration. ( ( ‘ I am, sir, 6 ‘ Your obedient servant, ‘( ‘ (Signed) W. B. HERERDEN, ( ( Assistant Secretaiy. ‘ I ‘ M. C.~K’I’EIGHE, EsQ.’ ” From the Proceedings, Part I., 1893. ( ( Complaints having reached the Council regarding the action of the Board of Inland Revenue with respect to stills used by analytical chemists and other members of the Institute, a memorial setting forth the conditions under which the stills are used was laid before the Chairman of the Board by Mr.M. Carteighe. The letter received in reply (Proceedings, Part II., 1892, p. 5 ) not being quite satisfactory, further representations were made to the Board, with the effect that they have issued instructions to the officers of the Board that professors, teachers of chemistry, and analytical chemists shall be allowed the use of stills for purely professional work in all cases in which no manufacture of any article for sale from or with spirit is carried on.” From the Proceedings, Part I”., 1907. “StiZZs.-The Board of Inland Revenue having informed a Fellow of the Institute that the use of a still of more than one gallon capacity for distilling water will not be allowed without a licence being taken for it, the Council have com- municated with the Chairman of the Board of Inland Revenue, drawing his attention to the fact that, after representations had been made by the Institute in 1892, the right to apply for exemption from taking licences was granted to professors and teachers of chemistry and analytical chemists using stills solely for the purpose of40 THE ANALYST.distilling water without any restriction as to the capacity of the stills, and that it would seem unnecessary now to impose a 1imita.tion. Seeing that such restriction would be tantamount to removing the privilege which has already been granted, the Board has been asked to reconsider the matter.” The Board, in reply, expressed their regret that the circumstances of the application referred to above had not been fully taken into consideration when their previous decision was arrived at. They have no desire in general to recede from the position taken up by them in this matter as indicated in the letter addressed to hfr, Carteighe (Zoc. cit.). A h e n c e would not be required for the still in question.

ISSN:0003-2654    

DOI:10.1039/AN9083300038

出版商:RSC    

年代:1908

数据来源: RSC

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40 THE ANALYST. NEW BOOKS. A TEXT=BOOK OF ORGANIC CHEMISTRY. By A. F, HOLLEMAN, Ph.D. Translated from the third Dutch edition by A. JAMIESON WALKER, Ph.D., B.A. ; assisted by OWEN E. MOTT, Ph.D.; with the co-operation of the Author. Second English edition, rewritten. New York, U.S.A. : John Wiley and Sons. London : Chapman and Hall. Price 10s. 6d. An octavo volume, containing 562 pages of subject-matter, 80 illustrations, and index; 34 pages are assigned to introductory matters, 312 to the consideration of fatty compounds, 191 to aromatic compounds and substances related to them, 6 to alkaloids, and 15 to the proteids. ORGAXIC CHEMISTRY. Including Certain Portions of PHYSICAL CHEMISTRY for Nedical, Pharmaceutical, and Biological Students. With Practical Exercises. By H. D. HASKINS, AiB., M.D., and J. J. R. MACLEOD, M.B., D.P.H. First edition London : Chapman and Hall. . Price 8s. 6d. A duodecimo volume, containing 342 pages of subject-matter, 24 illustrations, a New York, U.S.A. : John Wiley and Sons. note to the instructor, certain reference tables, and an index. IMMUNE SEXA. By Dr. CHARLES FREDERICK BOLDUAN. Second edition, rewritten. New York, U.S.A.: John Wiley and Sons. London: Chapman and Hall. Price 6s. Gd. There are 10 illustrations. The book claims to be a, concise exposition of our present knowledge concerning the constitution and mode of action of antitoxins, agglutinins, haemolysins, bacteriolysins, precipitins, cytotoxins, and opsonins. X duodecimo volume, 154 pages, including index.

ISSN:0003-2654    

DOI:10.1039/AN9083300040

出版商:RSC    

年代:1908

数据来源: RSC