摘要:

THE ANALYST’. FEBRUARY, 1900. OBITUARY NOTICE. THE LATE MR. GEORGE JARi\llAIN. WE regret to have to chronicle the death, at the age of seventy-three years, of an old member of our Society, Mr. G. Jarmain, F.I.C., F.C.S., which took place at Huddersfield on January 16. Mr. Jarmain held the post of Public Analyst to the Huddersfield Corporation since the institution of that office. He was a native of York, and received his education at the Training College there. He first adopted the scholastic profession, but relinquished it for the study, and subsequently for the practice, of chemistry. He lectured at the Huddersfield Technical College for about forty years, resigning his post there only five or six years ago. His name is associated with several elementary works on chemistry, including his well-known and, for beginners, valuable little hook on ‘‘ Qualitative Analysis.” PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS.THFJ annual general meeting of the Society was held on Wednesday, January 24, in the Chemical Society’s Rooms, Burlington House. The President (Mr. W. W. Fisher, M.A.) occupied the chair. The minutes of the previous meeting were read and confirmed. A certificate of proposal for election to membership in favour of Mr. B. PI. J. Warren, A.I.C., was read for the second time; and certificates in favour of Messrs. Norman Parr Booth, sssistant to Mi.. Wm. Chattaway, Apothecaries’ Hall, London ; John Macallan, A.R.C.S.I., F.I.C., chief assistant to Sir Charles A. Cameron, Municipal Buildings, Dublin ; and C. T. Tyrer, Works Manager and Analytical Chemist, Stirling Chemical Works, Stratford, were read for the first time.Messrs. d. A. Foster, J. B. P. Harrison and 11. Lloyd Howard were elected members of the Society. The Hm. TREASCRER (Mr. 13. W. Voelcker), in presenting the accounts of the Society for the past year, said that the balance of receipts over expenditure during 1899 was considerably less than had been the case in the previous year. In 1898 he had been successfuI, with only one exception, in collecting all the subscriptions that30 THE ANALYST. were due, including nine outstanding from earlier years. Of the 1899 subscriptions nine remained in arrear at the end of the year, while there had only been one outstanding subscription to collect, and the balance of income for 1899 had been affected accordingly.The expenditure during the year had been carefully kept down. The cost of the ANALYST was slightly less than in the previous years. The expenses of meetings were somewhat higher, owing to the fact that one more general meeting and three more council meetings had been held. I n petty disbursements, postage, and expenses of a similar class, a considerable saving was shown, while in the case of printing and stationery there was an increase of about 63. A somewhat unusual item of expenditure appeared, namely, law charges, which had been incurred for the benefit of a, member whose interests had been in danger of being prejudicially affected by the action of a, certain County Council. I n the early part of 1899 the Society’s investments had been increased by the purchase of $100 25 per cent.annuities. The securities held by the Society comprised €300 Consols and $200 21 per cent. annuities, as against only 6150 Consols at the end of 1894, an increase which, made as it had been in the short space of five years, might be regarded with considerable satisfact ion. On the motion of Mr. G. ENBREY, seconded by Mr. P. A. E. RICHARDS, the accounts were unanimously adopted. Votes of thanks to the Hon. Treasurer and Auditors were unanimously passed. The President then delivered his annual address. A vote of thanks to the President for his address was proposed by Mr. HEHNEK, with the request that he would allow it to be published. This was seconded by Dr. DYER, and carried unanimously. The PRESIDENT, having responded, announced that the list of officers and members of Council nominated for the ensuing year had been without any exception accepted, and expressed his thanks to the Society for again placing him in the position of President. He felt that in that position he owed a great deal to the officers of the Society, and especially to the Hon. Secretaries as well as to the senior members of the Council. A vote of thanks was unanimously passed to the President and Council of the Chemical Society for permission to use their rooms during the past year.

ISSN:0003-2654    

DOI:10.1039/AN9002500029

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

THE ANALYST. 31 ON THE DB~TERMINATION OF THE IODINE VALUE. (IlecLtl tit the Xeeti?zq, December 6, 1899.) I RE.\U with great pleasure the paper by a h . Lewkowitsch on this subject recorded in the ANALYST, p. ‘257, and am desirous of making the following observations on the subject-matter of it : I. Iodine Vcdrtcs foiiiid j o i . Ally1 ,-IlcohoE.--I fully agree with Dr. Lewkomitsch that ally1 alcohol is not a substance specially suitable for deciding the respective values of the different methods for determining iodine values. The rapidity with32 THE ANALYST. which the addition process takes place in allyl alcohol being less than that of the oil which has the smallest rapidity (linseed-oil), allyl alcohol demands a greater additive force on the part of the liquid than is necessary in its ordinary application.From some experiments published in my first paper (Zeits. ,f. -17tn7. Cliew., 1898, 277), Dr. Lewkowitsch calculates for allyl alcohol the iodine value 392. These experiments are, however, unsuitable for this purpose. The whole series was made merely with a view to determining the splitting off of acid from the IC1-addition product, and in order to have this splitting-off process as uncomplicated as possible, and not affected by the formation of acid which always takes place when a Hub1 solution is allowed to stand for any length of time, the duration of the reaction was kept very short (quarter to half-an-hour). The iodine values calculated from these experiments are therefore much too low, particularly for substances such as allyl alcohol, linseed oil, or cholesterol, which posseqs a small rapidity of addition.Dr. Lewkowitsch obtained with IC1-acetic acid liquid for a sample of allyl alcohol iodine values of 419-420, and with the Hub1 method 421-428, whereas I found with the same sample with IC1-acetic acid liquid 429. and for another sample by Hubl’s method 425. The diflerence between the results obtained with the same method depends, as is evident from a letter I received from 111.. Ilewkowitsch, upon a different method of working, ic., having a different excess of iodine present. I always used an excess of about 75 per cent. of the quantity originally added, whereas Dr. Lewkowitsch writes that he also in every case employed an excess of 75 per cent., and in most cases considerably more, approximating to 100 per cent.It is evident that this can only have been 75 to 100 per cent. of the quantity of halogen absorbed, i.e., only 43 to 50 per cent. of the quantity originally added. I t is, therefore, not at all a matter of surprise that n r . rlewkowitsch obtained lower iodine values than mine. 11. E f e c t of Time o n the ICI-acetic i4citl Liquk/.--Dr. Lewkowitsch finds that a solution of iodine chloride in 95 per cent. acetic acid is much more liable to alteration (decrease) than a solution in an acid of 99 per cent. When the acid is pure and especially free from oxidizable matters, there is, theoretically, no possibility of any decrease, Dr. Lewkowitsch found that a solution in 95 per cent. acid, after sixty-four hours, had decreased 4 per cent.of its value; whereas I had stated (Berichte d . cleutsch. Chew,. Ges., xxxi., 750) the decrease to be 0.3 per cent. in ninety-six hours. I can find no other explanation for this difference than the assumption that Dr. Lewkowitsch’s 95 per cent. acid was not so pure as mine. 111. In the third place, Dr. Lewkowitsch writes that the iodiue determinations made with Riibl solution lead to correct results provided that the Hub1 niethod is applied in a proper manner, and further on he says that the solution should not be allowed to act longer than six or seven hours on the fat under examination. I must add here that this limitation to seven hours only bears reference to those cases in which, in the first place, fresh (e.y., sixteen-hours-old) iodine solnt’ion is used ; and, secondly, where an excess of about 75 per cent.of the added iodine is employed. When treating oils of a high iodine value (e.g., linseed oil) with a Hiibl solution that is not fairly fresh, say about five days old, twenty-four hours are required. I t is clear that what I call a proper application of the FTiibl method is but littleTHE -4N:ILPST. 3 3 different from the usual one carried out in the case of oils with a low iodine value; whereas in the case of oils with a high iodine value the difference is greater. I was therefore convinced that the iodine value of linseed-oil especially required a revision, and I niade one (Keviic ii. t l . Fett- unt7 Oeliiidustrie, 1899, 29). This paper not having appeared in the ANALYST in abstract form, I give a short account of it. I determined the iodine values of eighty-six samples of guaranteed pure linseed- oil, all from seeds of known origin ; sixty-nine were pressed from unmixed seeds, and seventeen froin mixed.The results were as fol!ows : Iodine Values. Dutch linseed oils ... ... Froni 191.5 to 201.8 Korth Russian (Baltic) oils . , . South Russian oils ... ... ,, 176.3 ,, 186 3 Indian oils ... ... ... ,, 182.2 ,, 187.5 La Plata oils ... ... ... ,, 174-7 ,, 182-7 North American oils ... ... ,, 1 ' i i . S ,, 18S.5 ,, 192.1 ,, 200.0 (only one had a value 188.5) The more rapidly-drying varieties (Outch and North Russian), which are only used for paints and varnishes, have higher iodine values than those used solely €or soap- making. I also determined the specific gravity a t 15' C.of twenty-four of these samples, and found the following relation between this constant and the iodine value : Iodine l'alues. Specific Gravity. One sample . . ... Higher than 200 ... ... ... ... 0.9352 Mean of four samples .,. ... Between 195.0 and 200.1 ... ... 0.9339 7 7 f ? 7 ) ... ... 190.0 ,, 195.1 ... ... 0.9329 9 , ?, 1 , ,, 185.0 ,, 190.1 ... ... 0.9322 9 , six 9 , ... . . . ,, 180.0 ,, 185.1 ... ... 0.931'7 7 , five Y , ... Lower than 180.1 ... ... ... 0.9310 J , ... ... DISCUSSION. Dr. LEWKOWITSCH said that although Dr. Wijs and hiiiiself were more or less in agreement on this subject,.there were one or two points raised in the paper which seemed to require correcting or amplifying. He was very glad that after all Dr.Wijs agreed with him in thinking that allyl alcclhol was not a, suitable substance to decide the question at issue. I t had, in fact, been introduced by it third party, and it was this that had led him (the speaker) to cslculate, from one of Dr. Wijs' former papersp the number 392. Dr. Wijs thought that he could explain the divergenca in the iodine numbers of the saiiie sample of allyl alcohol examined by both (viz. : Wijs, 436; Lewkowitsch, 420), by the fact that dift'erent excesses of the reagent had been used. There was, indeed, some misunderstanding as to the excess to be employed. Dr. Wijs considered that if from 100 parts of iodine added 25 were absorbed, an excess of 75 per cent. was used, whereas he (the speaker) should call that an escess of 300 per cent.However, he had started a number of experinients for the purpose of settling this point. The following figures showed that the variations bet ween different observations were sometimes greater than those due to differences of excess, and it would seein that it did not really much matter whether one worked with an excess--in JVijs' sense---of He quite accepted the author's remarks on this point.34 THE ANALYST. 75 per cent. or 43 per cent. (or, as he would call it, 300 per cent. and 100 per cent. respectively) : Excess of Iodine Substance. Ally1 alcohol ... ... I , 2 , Linseed oil ... . . . . . . . Candle-nut oil 7 7 9 7 Oleic acid ... 7 7 9 7 9 7 9 7 7 9 Y 9 ... ... ... ... ... ... ... ... ... .._ ... ... ... ... ... ... ... ... ... ... ... ... ... ... ...... ... ... ... ... . I . ... . . . ... ... ... ... ... Iodine Value. ... 413.2 ... 416.0 ... 416.0 ... 179.8 ... 180.9 ... 179.3 ... 178.6 ... 163.4 ... 1G34 ... 163.1 . . . 159.1 ... 163.9 . . . 163.9 . . . 169.1 ... 162.1 ... 53.9 ... 83-25 ... S2.81 ... H3.W in W . ’ a sense. Per cent. 73.7 52.8 33 *ti 77.6 76.0 57.2 52 -5 73.6 72.99 53.4 49.5 77-5 77.5 51.6 51.6 76.1 73.9 52.7 50.0 in L.’s sense. Per cent. 281.2 89.3 89.3 347 315 133 110 278 270-3 115-0 97-9 308.9 308.9 106 -8 106% 319-9 983.2 115.5 100.4 -4s a rule, the excess he used was not calculated beforehand, but left more or less to chance, and varied generally between, say, 100 per cent. and 150 per cent. (in his own sense). But even making the largest possible allowance, the difference of abmt 1 per cent.in the value of allyl alcdml did not explain the difference of Dr. Wijs’ own figures for allyl alcohol. He thoaght, therefore, that the matter might fairly be allowed to drop there, accepting the conclusion that it did not really inalter whether the excess was 300 per cent. or half of that, because, according to the law of mass action, secondary reactions were bound to occur with the possible formation of sub- stitution products, thus probably introducing greater errors than those due to differences in the excess. The temperature variations had only a very slight influence, as Dr. Wijs himJelf had shown. The explanation Dr. Wijs had given for the some- what rapid decomposition of the spe;tkdr’s solution, prepared with 95 per cent. acetic acid-viz., that the acid had been impure-did not hold good, it having been prepared from pure glacial acetic acid, it was the same sample from which the 100 per cent.glacial acid solutions were made later on. With regard to the figures given by Dr. Wijs for the various linseed oils, these numbers were very valuable as far as they went, but they ought not to be taken as indicating the order in which the oils derived from the various countries ranked in quality (or purity). He himself had examined some Indian linseed oils, the iodine value of which canie up to 193, tested by the old Hiibl process, allowing the solution to act from four to six hotzrs. The specific gravity table showed the regularity one would expsct, as tha h i g h the iodine value, i.e., the larger the quantity of linolic and linolenic acid present, the higher the specific gravity must be, since the specific gravities of linolic and linolenic acids were higher thanTHE ANALYST.35 that of oleic acid. But it would not be permissible to allow the rule shown by the table to pass into literature as a general one. Mr. A. MARSHALL said that, in his experience, solution made even with perfectly pure acetic acid, although it lost very little strength during the first few days, showed on keeping for some months a considerable decrease in strength, and became much darker, probably owing to chlorination of the acetic acid and reconversion of the iodine chloride into iodine. Dr. LEWKOWITSCH said that in Dr. Wijs’ process long hours of standing were not permissible at all. The author, in his fourth paper, had proved pretty accurately the occurrence of side reactions after a certain time, which affected the result in a reverse direction. This was well known to every observer, for if after titration of the iodine the solution were allowed to stwnd it becanie blue again. One of the chief points in Wijs’ work was in showing that the importance which had been attached t o a standard time for exposure was wall founded, and that it was necessary to adhere strictly to a certain period, sufficiently long to insure the reaction coming to an end. He (Dr. Lewkowitsch) had been able to show that Hiibl’s method gave identical results with that of Wijs’, but in the case of the latter the solution would keep for at least half a year, so that a blank determination was not absdutely necessary, and actually less time was required for a test than for a determination of the saponification value. I t was so easy in preparing the Wijs’ solution to hit exactly the point when the titer was doubled that thereseemed to b3 QO necessity for having a n excess of either chlorine or iodine. He considered that a point had bean reached when the discussions on, and the endless modifications of, the Hub1 process might with advantage cease.

ISSN:0003-2654    

DOI:10.1039/AN900250031c

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

THE ANALYST. 35 ON A METHOD FOR DISTINGUISHING BETWEEN HOPS AND QUASSI.4. BY ALFI~ED C. CHAPMAX, F.I.C. ( R e a d ut t h e M e e t i u g , Decenabey 6, 1899.) IN the course of an investigation of the resinous constituents of hop-flowers, the results of which have been published elsewhere, I observed that these substances, when extracted from the hops by means of ether, yielded a somewhat considerable quantity of valeric acid on oxidation with an alkaline solutioii of potassium per- in anganate. I t occurred to ine at the time that this fact inight serve as the basis of a method for distinguishing between hops and quassia in fermented and other beverages, and the following experiments which I have since made show that such is the case. In the first place, quassia-chips themselves were extracted with dry ether, and the small quantity of extract so obtained was submitted to the action of alkaline pernianganate solution, but no veleric acid was obtained.I n order to arrive at the best conditions for the application of this method, f'ermented liquids of various kinds, bittered with hops on the one hand and with quassia on the other, were prepared in the laboratory in the following manner:36 THE ANALYST. Cane-sugar solutions and malt-worts were prepared, containing in some cases 5 per cent., and in others 10 per cent., of dry solids. Each of these was divided into two portions, hops being added to the one at the rate of 10 grammes per 500 C.C. of the solution, whilst 2-5 grammes of quassia chips were added to the other. For equal weights, the quassia wood has roughly four times the bittering power of good strong hops, and if used to replace the latter, the quantity to be employed would probably be calculated on this basis.Both solutions were then boiled gently in covered beakers for one hour. At the end of this time they were filtered, yeast was added after cooling, and the solutions were allowed to ferment for several days. The ‘‘ artificial beverages ” so prepared were then submitted to the following treatment: 500 C.C. were evaporated on a water-bath in a porcelain basin, fine recently-ignited sand being added towards the end of the operation, and the mass constantly stirred with a steel spatula to prevent it from adhering strongly to the surface of the dish, The residue was then transferred to an air-oven, and when quite dry was finely powdered in a mortar.This powder was next digested for some time with ether in a stoppered bottle, and the ethereal extract filtered into a flask, the ether being recovered by distillation. The flask was placed on a water-bath to drive off the last traces of ether, and the small quantity of residual matter oxidized by the careful addition of an alkaline solution of potassium permanganate, containing 40 grammes of parmanganate and 10 grammes of caustic potash per litre. This solution should be added in very small quantities at a time, the flask being vigorously shaken, and if necessary warmed. When the permanganate ceased to be readily reduced, a few drops of a hot solution of oxalic acid were added to complete the reduction, and the colourless liquid was filtered from the oxides of manganese into a glass dish, in which it was evaporated to dryness.The dry residue was then acidified with dilute sulphuric acid, when the odour of valeric acid in the case of the hop- bittered liquid became at once apparent, being rather accentuated by the carbon dioxide liberated at the same time from the potassium carbonate formed during the oxidation. I may say that the smell observed is not that of pure valeric acid, but of valeric acid plus sonie other odorous compound, which serves to render it more characteristic. I n the case of the quassia experiment the liberated acid is chiefly acetic, with, of course, carbon dioxide, and only in a few cases was there any marked odour, which, however, was altogether different from that obtained from hops.In the above experiments old hops responded as readily to this test as new hops. Experiments were next made with beer itself. One litre of the beer was evaporated with sand, and the residue from the ethereal extraction treated as described above. I n one or two samples of mild ale the indication was uncertain, but in all the samples of bitter beer and i n the majority of the mild ales and porters exatniued this valeric smell was unmistakable. Camomile extract behaves in a similar manner to hops, but chiretta yields no valeric acid. This method is readily applicable to the examination of hop-bitter preparations (of a medicinal character), hop extracts, and similar products. I t is also capable of furnishing additiond evidence in the case of fermented beverages which have heenTHE ANALYST. 37 examined according to the systematic schemes in vogue, and which have yielded results of an uncertain nature. In applying this method, it is important not to carry the oxidation of the ether residue too far. At first the permanganate solution is reduced readily, the mixture becoming warm, but towards the end it is usually necessary to heat slightly. With a very little experience there is no difficulty in arriving at the proper conditions, which cannot be definitely laid down, since the matter extracted by the ether varies both in character and quantity, and it must therefore be left to the operator to decide when the oxidation has been carried sufficiently far.

ISSN:0003-2654    

DOI:10.1039/AN9002500035

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

THE ANALYST. 37 ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. (Aim. c7e Chiwz. a i d . , 1899, iv., 338-342.)-The author describes the tests used in the Municipal Laboratory in Paris. The one principally relied upon is that of Jorissen (ANALYST, xxii., 282), in which 25 C.C. of the milk are shaken with 10 C.C. of a solution of phloroglucinol (1 gramme per litre), and subsequently with 5 to 10 C.C. of a solution of pohassium hydroxide (1 of the ordinary laboratory solution with 2 of water). It has been found, however, that in the proportion in which foriiialin is frequently met with in milk in Paris (1 : 10,000) there is a possibility of the colour being mistaken for that given by the potassium hydroxide alone with milk which has previously been boiled or artificially coloured with annatto, turmeric, or chrysoin yellow, and to eliminate these chances of error the following preliminary tests are made : Ten C.C.of the milk are shaken with 20 C.C. of Adanis' arninoniacal mixture of alcohol and ether. If after a few seconds the lower layer is completely opaque instead of being semi-transparent, the milk is regarded as having been boiled, thus altering the nature of the casein. When the lower layer is of a greenish tint and slightly fluorescent, annatto is indicated, acd may be identified as described by the author in former papers (ANALYST, xxiii., 174 and 230). A red coloration of the lower layer points to the presence of turmeric, whilst chrysoin causes the upper layer to be golden yellow, and the milk itself gives a reddish-brown tint on treat- ment with potassium hydroxide.When, in the absence of these substances, formalin has been detected by Jorissen's reagent, confirmatory evidence is obtained by distilling the milk and testing the distillate with Gayon's reagent (0.1 per cent. aqueous solution of fuchsin, 1,000 C.C. ; sodium bisulphite solution, 30" Bh., 10 c.c.; and concentrated hydrochloric acid, 10 c.c.). The milk itself is also tested by Denigds' method (ANALYST, xxj., The Detection of Formalin in Milk. A. Leys. 285). c. L4. 11.38 THE ANALYST. Chemical Composition of Butter Fat. C. A. Browne, jun. (Joz~nz. Anzer.. Chenz. SOC., vol. xxi. [lo], pp. 807-$27.)-The quantities of mixed acids and corre- sponding triglycerides determined in the butter examined are : Dioxystearic .. . ... ... Oleic ... ... Stearic . . . Palmitic ... ... ... ... Lauric . . . ... ... ... ... ... ... Myristic ... ... . . . ... Capric . . . ... . . , ... Caprylic ... ... ... Caproic ... . . . ... ... Butyric ... . . . ... ... ... Acid. Per Cent. 1 .oo 32.50 1 -83 38.61 9.89 2.57 0-32 0.49 2.09 3.45 ... ... ... ... . . . ... . . . Trig1 yceride. Per Cent. 1.04 33.95 1.91 40.51 10.44 2.73 0.34 0.53 2-32 6.23 __ 94-75 100.00 The unsaponifiable matter, amounting to only about 0.1 per cent., was not further An elementary analysis of the fat gave results very closely according with the investigated. theoretical calculation from the above table, the values being : C. H. 0. E'er Ccmt. Per Cent. Per Cent. Actual ... ... ... 75.17 . . . 11.72 ...13.11 Theoretical ... ... 74-86 . . . 11.71 . . . 13-43 c. s. New Method of Estimating Starch. D. Crispo. (d?m. dc C'hhn. anal., 1899, iv., 289, 290.)-This is a rapid process, based on a polarimetric examination of an alkaline solution of the starch ; a 10.1732 per cent. solution of starch examined in a, 200 mm. tube, read at 100 Soleil-Ventzke-Scheibler divisions. 3.391 grammes of the sample are triturated with a little water, 50 C.C. of a 6 per cent. solution of potassium hydroxide added, and the liquid, after being diluted to about 140 c.c., kept for an hour on a boiling water-bath with constant agitation. When cold it is made up to 200 c.c., filtered, and examined with the polarimeter in a 200 mm. tube. The number of divisions, multiplied by 6, gives the percentage of anhydrous starch.The following results were thus obtained in the analysis of specimens of different commercial starches : Potato Starch. Maize Starch. Rice starch. ~~ Starch by polarization ... 81.3 80-7 81.6 85.45 85.05 . . . Ash ... ... ... 0.3 0.3 0.3 0.31 0.75 Proteid substances ... .,. 0.2 0.2 0.2 0.38 0.50 Water ... ... _ . . 17.9 17-9 17.9 14.42 14.56 99.7 99.1 100.3 100.56 100-86 -~ _ _ _ - ~ It has not yet been determined whether this niethod can be used for the determination of starch in cereals, but the lzvorotatory products formed by theTRE ANALYST. 39 action of the potassium hydroxide on the gluten and in the grain would probably be a source of error. other nitrogenous substances C. A. M. - Estimation of Starch in Yeast. D.Crispo. (Anit. de Chim. anal., 1899, iv., 220, 291.)-This is an application of the author's general polarimetric method (see preceding abstract). Fifty grammes of the yeast, which must be left until it has become soft, brown, and viscous, are stirred up in about 2 litres of water, and allowed to settIe for from ten to twenty minutes. The supernatant liquid is siphoned off, and the deposit again washed four or five times in the same way, until the washings are almost clear. Finally the deposit is transferred to a graduated flask, where it is mixed with water in the proportion of about 100 C.C. to each 1 to 2 gramines of starch. A solution of potassium hydroxide is then intro- duced, with continual agitation, so t'hat for each gramme of starch there is 1 gramme of alkali.The flask is filled to about three-fourths with water, heated on the water- bath for an hour, and the resulting solution examined with the s.-V.-s. polarimeter in a 200 mm. tube. The number of divisions, niultiplied by 0.10173, gives the percentage of anhydrous starch in 100 C.C. of the solution. The amount may be calculated on the moist yeast on the assumption that the latter contains on the average 18 per cent. of water. The mean correction for the starch removed during the washing has been determined experimentally by the author to be I1 per cent. The following analyses of test mixtures of yeast and starch were made by five different chemists, using this method : Starch added per cent. 13.8 5.66 1.96 3-85 6.00 4.00 2.00 100 5.0 C. A. M. >, found >, 13.0 6 4 2.29 4.35 6.50 4.00 2.02 10.32 4.97 The Detection of Sawdust in Flour.G. A. Le Roy. (Atin. de Clzim. anal., 1899, iv., 212, 221.)-After making experiments with various reagents used for the detection of woody fibre in paper, the author has obtained the most satisfactory results with an acid solution of phloroglucinol. This is prepared by mixing 1 grarnme of phloroglucinol with 15 C.C. ol 90 to 95 per cent. alcohol, 15 C.C. of water, and 10 C.C. of phosphoric acid syrup. I n examining a flour, 1 or 2 C.C. of this reagent are placed in a porcelain capsule, a pinch of the sample introduced, and the liquid warmed very slightly. After a few seconds any particles of sawdust present assume a rose tint which gradually darkens to carmine, whilst the cellulosic substances of the flour only become coloured subse- quently, and usually very slightly.The coloration given by maize and potato flour is much less pronounced than that of wood flour. sttempts to make this reaction quantitative have only given uncertain results. C. A. M. ~ -~ _ -40 THE ANALYST. Wines containing Citric Acid. R. Kunz. (Zcit. f i i r Unteuuch. C~CT Nahr. Z L I Z C ~ GeimssnzitteZ, ii., 692.)- Samples of so.called ‘‘ wine composition ” or “ wine essence ” examined at the Government Laboratory at Vienna were found to contain, besides tartaric acid, large quantities of citric acid. I t is believed that these preparations are used not only in the production of artificial wines, but also for adulterating natural wines, and this opinion is strengthened by the fact that many wines, particularly those of Italian origin, have been found to contain considerable quantities of citric acid. The detection of citric acid in wines having thus become a matter of importance, the following method is proposed as being reliable and free from possible objections : 50 C.C.of the wine are mixed with 5 C.C. of a 20 per cent. solution of lead acetate. The precipitate is filtered off, washed, stirred up with 50 C.C. of water, and 3 C.C. of a 20 per cent, solution of sodium sulphide added to separate the lead. Should any turbidity be produced, a few drops of acetic acid may be added. The lead sulphide is then removed 1)y filtration, the filtrate evaporated to dryness, the residue washed with the sinallest possible quantity of water into a beaker, ammonia added to slight alkaline reaction, double the volume of ammonium chloride solution added, and the tartaric acid thrown down by calcium chloride.The large excess of ammonium chloride present hinders the precipitation of the citric acid. On now evaporating the filtrate from the calcium talrtrate precipitate, the citric acid, if present, separates out in the foriii of crystals of calcium citrate. Or the filtrate from the calcium tartrate can be mixed with alcohol, the precipitate produced washed with alcohol, dissolved in a little hydrochloric acid, the solution made alkaline with ammonia and heated to boiling. This procedure has the advan- tage over the former that the removal of the aininoniurn chloride facilitates the precipitation of the calcium citrate.I n either case the crystals of calciuin citrate are identified by means of the microscope. 1%. H. B. S. Estimation of Succinic Acid in Fermented Liquids. J. Laborde and I;. Moreau. (Ainz. d e l’lmt. Q m t e u i * , 1899, xiii., 657 ; through Chew. Zeit. Rep., 1899, 283.)-Girard’s process, though accurate, is tedious owing to the low tempera- ture and slow speed of evaporation. If the Oemperature be raised, losses ensue, not because the succinic acid volatilizes, but because some of it combines with glycerin and does not take part in the final titration. The substance is preferably evaporated to dryness on the water-bath in presence of sand or fine shot, and the solid matter extracted with ether. The solvent is driven off, and in the dry extract free acid is estimated (1) by titration, (2) by saponification with an excess of potassium hydroxide, By adding the two yields together, the proportion of succinic acid is found ; but the results are generally 0.).to 0.2 granime too high per litre of sound wine. Proper correction, however, can be made by determining the volatile acids. Free tartaric acid may pass into the ether ; it must be converted into tartrate, estimated and deducted. If the original liquid contains more than 1 per cent. of sugar, extraction of the dry residue with ether is not coniplete; the sample inust be evaporated only to a syrup, mixed with alcohol in amount corresponding with theTHE ANALYST. 41 proportion of sugar, and then precipitated by the gradual addition of ether, repeating the whole process several times.F. K. L. The Limits to the Detection of Malt Substitutes in Beer. E. Prior. ( Z e k f i i r Ui~teuueli. der X d ~ r . uizd G e m s s m i t t e l , ii., 697-701.)-Experiments were made with the following mixtures : Forty-five grainmes of malt and 5 grammes of potato starch, 45 grammes of malt and 5 grammes of rice, 40 grainmes of malt and 10 granimes of potato starch, and 40 gramnies of malt and 10 grainines of rice. Each mixture was iiiashed in the manner customary in making malt analyses, the niash filtered, the graiu washed with hot water, and the wort boiled with 0.5 gramme of hops. After cooling and filtering, the proper quautity of yeast was added, and the liquid fermented. At the expiration of four days the beer was filtered and analysed. I n order to saccharify the added starch and rice as completely as possible, both were boiled to paste, and the rice in addition was steamed for three hours at 3 atmospheres’ pressure.The results are given in the following tables : diinlyses of the Potato StcLrclh C L ~ Eice. Ti1 the N2Ltural State. In the Dry State. Potato Starch. Rice. Potato Starch. Rice. Per cent. Per cent. Per cent. Per cent. - - Water ... ... 18.63 12-74 Water ... ... Starch ... ... 77.30 74-00 Starch ... 95.00 84.80 Nitrogenous matter - 8-25 Nitrogenous matter - 9.91 ... _ _ ~ _ _ _ _ _ _ _ : Starch. Starch. lialt. I Time of saccharification .. Condition of the wort ... Maltose in the extract ... 67.112 67.43% 1 69-03x Nitrogen in the extract ... 0*64~5/~ 0.5471; 1 0.279% A M t t IO,x Malt + 20% Rice.I Rice. 4:lErn. i 40-45 min. 67.15% , 68.30% 0.630% I 0.650% clear The following conclusions were arrived at : The time occupied in saccharifying is increased by the addition of starch or rice. With 20 per cent. of starch erythro-dextriu was still found at the expiration of an hour. The percentage of maltose and achroo-dextrin in the unferinented extract is not42 THE ANALYST. increased by the substitution of 10 per cent. of starch or rice, but is somewhat increased by a 20 per cent. substitution. The percentage of nitrogen in the unfermented wort extract is perceptibly reduced by the substitution of 10 per cent. of starch, and is reduced by more than half by the substitution of 20 per cent. Ten or 20 per cent. of rice does not reduce the proportion of nitrogen in the unfermented wort extract.The degree of fermentation of the beer is somewhat reduced by the substitution of 10 per cent. of starch, and more so by the substitution of 20 per cent. On the other hand, rice occasions a slight, increase. The percentage of maltose and achroo-dextrin in the beer extract is increased by starch or rice, especially by the former. The nitrogen of the beer extract is reduced but little below 1 per cent., and cer- tainly not below 0.9 per cent., by the substitution of even as much as 20 per cent. of starch. Rice increases the proportion of nitrogen in the beer extract. H. H. B. S. The Distinction of True Extract of Vanilla from Liquid Preparations of Vanillin. 1. Dilution Test.--A small quantity of the tincture, agitated with two volumes of water, should furnish a flocculent reddish-brown precipitate, but only slight turbidity, since milkiness indicates foreign resin, as does also niore than a slight turbidity ensuing on the addition of hydrochloric acid drop by drop to the diluted sample.If alkali has been used in preparing the extract, the turbidity is greater than otherwise, and the colour fades on addition of acid. 2. Testing the Resin.-Twenty-five C.C. of the extract under examination are evaporated on the water-bath to eliminate alcohol, and then made up to the original volume with water, The true resin forms an amorphous, flocculent, red to brown residue, separating out entirely on acidifying the solution with a little hydrochloric acid. It is soluble in caustic potash, giving a deep red solution, and is reprecipitated by acid.Unlike most other resins, this one gives little or no colour reaction with ferric chloride or hydrochloric acid in alcoholic solution. 3. CoZoz~i*i?zg Mnttc~:--(a) Caramel: A portion of the filtrate from the resin is concentrated on the water-bath until about as dark as the original tincture. Caramel, when present, will be thrown dom7n as a flocculent, yellowish-red precipitate on adding a few drops of strong hydrochloric acid and applying gentle heat. The precipitate is insoluble in water, strong alcohol, or ether, but soluble in dilute caustic potash, glacial acetic acid, or dilute alcohol. ( b ) Axo dyes: 9 portion of the filtrate is treated with ammonia-which deepens the colour of the true extract-and digested with zinc dust. If natural, the colour will revert to its original tint, or nearly so ; but azo dyes will be decolorized, the colour returning on exposure to air, or on addition of hydrogen peroxide.A portion of the original solution frotn the resin is tested for tannin, which should be present in sinall quantity only. Organic acids and extractives are contained in considerable quantity in the pure W. H. Hess. (Jorim. Amer. Chcvz. Xoc., vol. xxi. [9], pp. 719-723.)THE ANALYST. 43 extract, and their precipitation by lead acetate forms a decisive test of the genuine- ness of the sample. Couinarin, due to adulteration with Tonka extract, is detected by the method given in t J o u m . -diise?*. ( ' h m . soc., vol. xxi., p.256. c. s. Estimation of Essential Oil in Cinnamon-Water. M. Duyk. ( A I z ? ~ . dc Chim. anal., 1899, iv., 223, 224.)-The method employed consists in treating the preparation with phenylhydrazine and weighing the insoluble cinnamyl hydrazone formed. The cinnamon-oil of Ceylon and China consists almost entirely of cinnamic aldehyde, the proportion being as high as 90 per cent. in the Ceylon product. The phenylhydrazine solution is prepared by dissolving 1 gramme of phenyl- hydrazine hydrochloride and 1.5 gramme of potassium acetate in 10 C.C. of water. A suficient quantity of this reagent is added to the cinnamon-water to cause complete precipitation of the cinnamic aldehyde at the ordinary temperature, and the precipitate collected on a filter, washed, dried on a porous plate under a clock-glass, and weighed.In a test experiment the author dissolved 0.1 grainme of cinnamic aldehyde in 100 C.C. of water, and obtained 0.162 gramme of the hydrazone as against the theoretical amount 0.167 gramme. In an officinal sample the weight of the precipi- tate was 0.175 gramme, corresponding with rather more than 0.10 gramme of cinnamic aldehyde. The distilled waters of certain other essential oils, such as peppermint, rose, orange flowers, and camomile, do not yield any precipitate with phenylhydrazine, but the method is applicable to the estimation of benzaldehyde in cherry-laurel- water. As a general rule the presence of small amounts of alcohol in the waters do not interfere with the determination. C. A. M. Estimation of Santonin. J.Xatz. (-4 rch. P/tci?.??L., 1899, ccxxxvii. , 245 ; through C'hen?. Zeit. Rc~i., 1899, 233.)- The author rejects the processes hitherto employed, and proposes the following : Ten grammes of coarsely powdered santonica are extracted with ether in a Soxhlet for two hours. The solvent is distilled off, and the residue is cohobated for fifteen or thirty minutes with a solution of 5 grizmmes of crystallized barium hydroxide in 100 C.C. of water. After cooling, the liquid is saturated with carbon dioxide till it has an acid reaction, filtered quickly, and the carbonate washed twice with 20 C.C. of water. The filtrate is concentrated on the water-bath to about 20 c.c., mixed with 10 C.C. of 12.5 per cent. hydrochloric acid, and heated for another two minutes. The liquid is brought into a separating funnel, the crystals in the basin being dissolved in 20 C.C.of chloroform ; and basin, funnel, and filter are washed twice with 20 C.C. of the same solvent. The liquid is evapor- ated, and the residue boiled under a vertical condenser for ten minutes with 50 C.C. of 15 per cent. alcohol : the solution is filtered into a tared flask, and the insoluble matter treated twice again with 10 C.C. of boiling 15 per cent. spirit. After standing twenty-four hours, the flask and its contents are weighed, the alcohol is filtered44 THE ANALYST. through a weighed paper, flask and paper being rinsed with 10 C.C. of the same spirit (which is not included in the subsequent calculation). The filter is finally dried and weighed ; and to the weight of santonin so obtained a correction of 0.006 gramrne is added for every 100 gramnies of filtrate.F. H. L. The Assay of Cacodylates. R. Imbert and A. Astruc. ( J o z ~ m . Phnwn. C'him., 1899, x., 392-395.)-The fact that cacodylic acid--AsO-CH,-behaves as a neutral body with the indicator helianthine A, but is monobasic with phenol-phthalein, affords a rapid method of estimating it. Thus, in the case of sodium cacodylate, which is the salt most frequently met with in coiiimerce, 1 molecule of acid should be required to render the salt neutral to helianthine. But in practice the authors have found that the samples they have met with have not the theoretical neutrality to phenol-phthalein, but are, on the contrary, markedly acid. This they consider is probably due to the dissociation of the salt by water in a manner analogous to that of bimetallic glycerophosphates. In making an assay 1.6 grainiiie of sodium cacodylate is dissolved in 100 C.C. of water, giving a solution containing one-tenth of the molecular weight per litre. Ten C.C. of this liquid are neutralized with standard alkali, with phenol-phthalein as indicator, and then titrated with decinormal acid with helianthine as indicator. The number of C.C. required multiplied by 10 gives the percentage of pure sodium cacodylate in the salt. I n different commercial saniples the authors found by this method from 75.20 to 92-80 per cent. of pure sodium cacodylate, and from C)-G(i to 27.60 per cent. of free cacodylic acid. Cacodylic acid and cacodylates do not give the characteristic reactions of arsenates. C. A. M. 'OH \CH,,

ISSN:0003-2654    

DOI:10.1039/AN9002500037

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

44 THE ANALYST. ORGANIC ANALYSIS. The Detection of Acetylene by Means of an Ammoniacal Solution of Copper and Hydroxylarnine. L. Ilosvay and N. llosvay. (Berichte, 1899, xxxiii., 2697-2699.)- The colourless solution obtained by reducing an ainmoniacal solution of cupric sulphate with hydrosylamine can be used as a reagent for acety- lene, and the author has made experinients to determine under what conditions it is most sensitive and yields a copper acetylide of constant colour. He finds that the sensitiveness of the liquid is dependent on the amount of ammonia and hydroxylamine it contains. If the proportion of aininonia be only just sufficient to dissolve the copper salt and the hydrosylamine only sufficient to just decolorize the liquid, the precipitate formed by acetylene is at first yellowish- brown and subsequently green.If, on the other hand, the ammonia he in consider- able excess, and a correspondingly large amount of hydrosylamine present, the colour of the precipitate varies between a light and dark onion red. If there be tooTHE ANALYST. 45 little ammonia, a light yellow pulverulent substance (probably copper suboxide or cuprous hydroxide) is formed on the surface. This, however, does not destroy the sensitiveness of the reagent. As a general rule, the solution should contain from 2.5 to three times the amount of ammonia absolutely necessary, and from fifteen to eighteen times the quantity of hydroxylainine required to reduce the copper conipound. The author gives the following directions for preparing the reagent (50 c.c.) from the chloride, nitrate, or sulphate of copper : 1.Cupric ehloride (CuC1, 3H,O), 0.75 gramme ; ammonium chloride, 1.5 grainme ; ainmoiiiuin hydroxide (20 to 21 per cent. NH,), 3 C.C. ; and hydroxylamine hydrochloride, 2-5 graiiimes. 2. Cupric nitrate (Cu(NO:,),.5H,O), 1 gramme ; ammonium hydroxide, 4 C.C. ; and hydroxylamine hydrochloride, 3 grammes. ;3. Crystalline cupric sulphate, 1 grainine ; ainmoniuiii hydroxide, 4 C.C. ; and hydroxylamine hydrochloride, 3 grammeB. In each case the copper salt is dissolved in a little water, the arninonium hydroxide added, then the hydrosylainine hydrochloride, and the solution shaken and made up to 50 C.C. The solutions remain stahle for about three days, but on the fourth day become less sensitive, and subsequently begin to deposit a light red precipitate, whilst after fourteen days the metal is repidly reconverted into the cupric state.The presence of acetylene in coal-gas can be readily demonstrated by means of these solutions. A few C.C. of the reagent are placed in a 500 C.C. stoppered cylinder, the gas passed in until the liquid becomes rose-coloured, and the cylinder then closed and shaken, an immediate red precipitate being formed. C. A. M. Estimation of Invert Sugar in Presence of Cane-Sugar. H. Jessen-Hansen. ( X e d d e l e l s e i . ~ ~ a Carlsberg Lab., 1899, iv. [ 41, 314 ; through R & u m h in F N ? ~ L , ibid., p. 193.)--Bruhns has recently objected (ANALYST, 1898, xxiii., 297) to Kjeldahl’s method of estimating invert and other sugars with alkaline copper solutions ( h A L Y s T , 1895, xx., 227), on the ground that it is incorrect when cane-sugar is simultaneously present, for the latter precipitates a large and variable amount of copper, which vitiates the results of the analysis.Jessen-Hansen remarks that Kjeldahl was not dealing in his original communication with such materials as may contain cane-sugar, therefore the criticism is somewhat unjust ; but in order to render Kjeldahl’s process available when reducing sugars are mixed with large quantities of cane-sugar, he has reinvestigated the whole question. He finds that when 30 C.C. of Fehling’s solution, prepared according to Kjeldahl’s directions, but containing double the usual amount (10.4 instead of 5.2 grammes) of Rochelle salt are used, and when the time of boiling in a current of hydrogen is limited to five minutes, the weight of copper thrown down hy 10 grammes of cane-sugar is lowered from between 102 and 114 iiiiliigrammes to about 14 niilligramines, so that if the period of ebullition is governed exactly I)y means of a watch having a second-hand, concordant results can always be obtained.I t follows, therefore, that the figures given by Kjeldahl (ANALYST, 1895, ?ibi sup.) for46 THE ANALYST. invert sugar require modification in presence of cane-sugar ; and the present author accordingly appends to his paper a lengthy table for converting the weight of copper deposited into invert sugar (a) when the latter exists alone, and ( b ) when it is mixed with different proportions of cane-sugar.The figures for pure invert sugar also are not quite the same as those already recorded. F. H. L. The Odoriferous Principle of Jasmine Flowers. A, Verley. (l?zdZ. s'oc. Chim., 1899, xxi., 226-232.)---Numerous attempts have been made to isolate the essential oil of jasmine flowers by distillation with steam, but these have been unsuccesshl owing to the quantity of oil being very small, and to the fact that it is completely decomposed on boiling with acidulated water. The author has obtained it by enjlrzwnge in the cold. The fat saturated with the perfume was beaten with Vaseline-oil, and the latter extracted with acetone. On evaporating the acetone under reduced pressure a clear reddish-brown oil was left. A fractional distillation of 35 grammes of this substance under reduced pressure yielded 19 grammes between 70" and 180" c).under 15 mm. pressure, and a residue of 14 grammes of resinous matters. These 19 grammes on re-fractionation under 12 mm. pressure gave the following fractions: 70" to 100" C., 2 gramnies; 100" to 101" C., 11 grammes; 101" to 110" C., 3 gramnies; and 110" to 180" C., 2 grammes. The fraction distilling at 100" to 101" C. was a very mobile, slightly yellow liquid, with an intense odour of jasmine. I t had a density of 1.1292 at 0" C., and a composition corresponding with the formula C,,H,,O,. From its reactions it appeared to be the metliylene acetal of phenylglycol. To this substance, which was not quite pure, the author gave the name '' jasmal. C,H,. CH-CH., I / 0 0 This conclusion was confirmed by the synthetical preparation of that acetal. Fifty grizmmes of phenylglycol, 300 grammes of water, 125 grammes of sulphuric acid, and 100 grammes of formaldehyde were heated together on the water-bath, and the resulting clear supernatant oil removed by ether and rectified undp,r reduced pressure.It boiled at 100" C. under 12 mni. pressure, and at 218" under the ordinary pressure. In the pure state it had the characteristic odour of jasmine, and all the properties of the natural jasmal. When boiled with acidulated water phenylglycol and formaldehyde were regenerated. Homologous compounds were obtained in the same manner, another aldehyde of the fatty acid series being substituted for formaldehyde, but these had not so pronounced an odour of jasmine. Its density was 1.334 at 0" C.C. ,4. M. Essential Oil of Jasmine Flowers. A. Hesse and F. Muller. (li'ci~zchtc, 1899, xxxii., 565-574 and 765-779.)-The authors state that for some time past they have extracted the essential oil of jasmine by a method analogous to that described byTHE ANALYST. 47 Verley (see preceding abstract), but have found that it is preferable to purify the oil by distillation in steam rather than under reduced pressure. In this way they have determined the amount and characteristics of the oil recovered from numerous samples of jasmine pomade from the harvests of 1896 and 1897, and give the results of ten representative cases. I n these the amount of ethereal oil obtained from 1 kilo of pomade varied froin 3-95 to 5.95 grammes, and had the following characteristics : Specific gravity at 13" C., 1006-1018 ; optical rotation, + 2" 30' to + 3" 30' ; ester content in terms of linalyl acetate, 00*3-95*4 per cent.; in terms of benzyl acetate, 69.1-73.0 per cent. One of the authors showed in a paper some years ago that the high percentage of esters in ethereal jasmine-oil was to be attributed to the presence of large quantities of benzyl acetate. Since Verley has stated that the odoriferous principle in jasmine-oil is phenyl- glycol-methylene acetal, the authors have examined products obtained in exactly the same manner as described by Verley. Phenylglycol-methylene acetal prepared by the condensation of phenylglycol and formaldehyde, by means of dilute sulphuric acid, is not acted upon by alkalies ; but on treatment with oxalic acid it is decom- posed, with the liberation of phenyl glycol, which can readily be identified by its characteristic crystalline form, and the formation of phenyl acetaldehyde on heating it with dilute sulphuric acid.Having proved that in this way it was possible to detect small quantities of the acetal in the presence of linalol and of benzyl acetate (in large excess), the authors tested the different fractions yielded by the distillation of 60 grammes of jasmine-oil under reduced pressure, but in none of them could any trace of phenylglycol-methylene acetal be detected. The odoriferous principle was found to be due in the main to two substances, which together only amounted to 5 per cent. of the total volatile oil, and neither of which was Verley's acetal.I n order to determine the amount of the various constituents in jasmine-oil, a method based on the behaviour of these substances towards periiianganate was devised. It was proved experimentally that linalol, when thus oxidized, yielded carbonic an'd acetic acids, but no solid acid. Benzyl alcohol, however, was converted into benzoic acid, and in a test experiment 94-5 per cent. of the theoretical quantity was obtained. Crude linalyl acetate, prepared by boiling linalol with acetic anhydride and sodium acetate, behaved in an analogous manner to free linalol, and yielded carbonic and acetic acid and a small amount of an oily, soluble acid, but no solid acid. Benzyl acetate, in the absence of alkali, was not attacked by permanganate. As a test of the applicability of this method to the examination of jasmine-oil, a mixture *-as prepared consisting of 30 per cent, of benzyl alcohol, 50 per cent.of benzyl acetate, 10 per cent. of linalol, and 10 per cent. of crude linalyl acetate (con- taining about 59 per cent. of that acetate). This mixture had a saponification value of 201, the calculated value being 200.2. The mixture during oxidation was kept as neutral as possible by the addition of dilute sulphuric acid, and the temperature mas maintained at from 15' to 20" C. by48 THE ANALYST. adding ice. The permanganate was added at first in a 3 per cent. solution, and subsequently in the form of a fine powder, which was introduced little by little, with constant agitation, until the colour remained perinanent for about an hour.The excess of perinanganate was removed with bisulphite, and the oxidized liquid extracted three or four times with ether. The acid oxidation-products were removed from the ethereal extract by shaking the latter with a dilute solution of sodium hydroxide. The residual ethereal layer was washed with water, dried with calcium chloride, and evaporated to dryness at 40" C. in a weighed and exhausted flask. The alkaline extract was added to the original residue from the ethereal extrac- tion, the mixture rendered slightly alkaline, filtered, the filtrate concentrated by evaporation and freed as far as possible from inorganic salts by the addition of alcohol, and the benzoic acid determined by rendering the liquid acid and filtering. In this way, from 20 grammes of the above mixture, 9.8 gramtnes of benzyl acetate ( = 98 per cent.of the theoretical amount) and 6.6 grammes of benzoic acid (97.5 per cent. of the theoretical quantity) were obtained. From these results the authors concluded that the method was capable of determining the amount of these substances within 2 to 4 per cent. of the real quantity. Having proved qualitatively that the different fractions obtained in the fractional distillation of essential oil of jasmine consisted chiefly of linalol, linalyl acetate, benzyl acetate, and benzyl alcohol, the authors employed the oxidation method described above for a quantitative estimation, in which the percentage of linaljl acetate was calculated from the difference between the ester content of each fraction, and the amount of benzyl acetate actually found.From the results obtained in the examination of the fractions and of the original crude substance, they came to the conclusion that the essential oil of jasmine flower contains in round numbers : Benzyl acetate, 65 ; linalyl acetate (and other terpene alcohol esters), 7.5 ; benzyl alcohol, 6 ; other odoriferous constituents, 5.5 ; and linalol (and other sub- stances), 16 per cent. Hesse (Berichte, 1899, xxxii., 2611-2620) has continued the research on this subject commenced by himself and Rlliiller. He finds that, in addition to the oxygen compounds described in the former papers, certain nitrogenous coinpounds are present and have a considerable influence on the nature of the perfume. Of these the more important is indol (C,H,?N), which can be isolated by pre- cipitation with picric acid.The author also states that the constituent of the oil which reacts with picric acid and the '' aldehyde " of jasmine-flower-oil isolated by means of sodium bisulphite are identical. The methyl ester of anthranilic acid (NH,.C,H,.CO,.CH,) is also present in small amount (not exceeding 0.5 per cent.). This ester, which has also been found by Walbaum and Erdinann in neroli-oil, gives in dilute solutjon the blue fluorescence of jasmine-flower-oil. When present in greater quantity than 1 per cent., it can be precipitated as a snlphate by addiug a mixture of sulphuric acid and ether. Its influence on the jasmine perfume is much less than that of the indol. The residue was benzyl acetate.It amounts to about 2.5 per cent. of the crude oil.THE ANALYST. 49 A third new constituent has been isolated from the fraction of the jasmine-oil distilling between 105" and 107" under 5 mm. pressure. This is a ketone of the formula C,,H,,O, to which the author has given the name of jasmom. It is a light yellow oil, becoming darker on keeping, and having an intense odour of jasmine. It has a specific gravity of 0.945 at 15" C., and boils at 257" to 258" C., under a pressure of 755 mm. I t can readily be isolated as a semi-carbazone, which when purified by one crystallization from boiling alcohol melts at 204" to 206" C. The pure jasinone oxime (C1,H1,NOH) crystallizes from dilute alcohol in fine needles which melt at 45" C., and are volatile in a current of steam.Frorn the results of the investigations described in this and in the former papers, the author gives the following as the composition of the ethereal oil of jasmine flowers : Jasinone, 3.0 ; indol, 2.5 ; methyl ester of anthranilic acid, 0.5 ; benzyl acetate, 65.0 ; linalyl acetate; 7.5 ; benayl alcohol, 6.0 ; and linalol, 15.5 per cent. c. A. nl-. - Bishop's Reaction for Sesame Oil. H. Kreis. (Chenz. Zeit., 1899, xxiii., 802.) -In 1892 Ambiihl mentioned that on testing an old rancid sample of sesame5 with the Baudoin reaction, he obtained a Idue colour instead of the usual red, a peculiarity which has not hitherto been explained. Quite recently the present author, examining a saccharine secretion from larch needles with sesami: and hydrochloric acid in order to test for sugar, obtained a blue-violet colour when the oil was rancid, but the normal red tint when a fresh specimen of sesami! was substituted.I t seemed, there- fore, that this blue might be a mixture of the Baudoin red with the green, which, as Bishop discovered ( J o z L ~ . Phnmz. Clzi7u., 1889, [5], xx., 244), is produced when old sesaint: oil is shaken with 1-19 hydrochloric acid ; and experiments showed that, by mixing together the coloured acids from the two tests, Ambiihl's blue could be imitated in its various shades. The blue colour with rancid sesamb appears more distinctly when sugar is used than with furfural. Bishop's test gives at first a yellowish-green tint, which gradually changes to bluish-green, while the oil finally beconies pale violet.In the presence of resorcinol or phloroglucinol, Bishop's acid tnrns violet or orange-red, but other phenols exert no influence on the colour. Bishoprecomniended his test as a nieans of judging the age of sesami: oil, but as the reaction seems to be caused by oxidized products, substances similar to which may be present in other oils, it is not surprising that an analogous green colour is produced when certain other rancid fats mixed with fresh sesamC! are agitated with strong hydrochloric acid. For instance, an old olive oil (acid No. 5) gave no colour on shaking with acid, but after being mixed with an equal volume of a sesami! oil, which itself yielded no reaction, the whole immediately produced a green tint. The same phenomena were observed with old butter (acid No.6) and lard (acid No. 2) ; neither coloured the acid alone, but with indifferent sesami: oil both gave the Bishop reaction. The investigation of this subject is being continued ; in the meantime, it seems that Bishop's reaction is shown most strongly by those oils which still possess ;t normal acid number, but which are shown to be rancid by their taste. I?. H. L.50 THE ANALYST. Some New Reactions for Sesamb Oil. F. Breinl. (Clzenz. Zeit., 1899, xxiii., 647.)-The furfural test for sesame (ANALYST, 1896, sxi., 135) appears not only in presence of strong hydrochloric acid, but also if other dehydrating agents are used, such as sulphuric acid diluted with water, or preferably with glacial acetic acid. Other aldehydes--presumably all the aromatic compounds-give similar reactions ; but the exact colours vary with the reagent employed.Benzaldehyde and cuininol yield an orange ; o-nitrobenzaldehyde, an orange-yellow : 21-nitrobenzaldehyde, a yellow ; cinnarnic aldehyde, 0- and p-hydroxybenzaldehyde, vanillin, and piperonal all give a violet-red tint. Neither formaldehyde nor acetaldehyde produces a colour with sesame oil; but as cinnamic aldehyde does, it would seem that unsaturated fatty aldehydes should behave analogously. Crotonic aldehyde, even in very dilute solution, yields an orange coloration. As these colours are very similar to those given by furfural, etc., with albu- minous substances, it would appear probable that the actual cause of the reaction might, be a nitrogenous albumin-like body in the sesamCi oil.Evidence of this cannot be obtained ; nevertheless, repeated extraction of sesamh with strong hydrochloric acid removes froiii the oil the power of yielding colours, while the aqueous liquid shows a noteworthy colour. The acid extracts also contain a minute trace of nitrogen. Inasmuch as animal fats have been shown to contain alburninoids, it is not improb- able. that vegetable fats, especially those which have not been refined with strong acids, should contain proteids ; and as al1)urninoids give the above-inentioned furfural reaction, it is not surprising that some samples of olive and castor oils have responded to the Baudoin test. A few specimens of the latter have also reacted with piperonal and vanillin; hut the colours were so faint as to be overshadowed by the addition of 1 per cent.of sesamh. Experiments have been made to determine the comparative delicacy and general utility of the several aldehydes as reagents for sesame oil ; and seeing that many fats give red or brownish colours on shaking with strong hydrochloric acid alone, those substances are preferable which yield tints bluer than that produced by furfural. On the whole, p-hydroxybenzaldehyde, vanillin, and piperonal are to be recommended ; and their dcoholic solutions have the advantage of being permanent for months when exposed to light. On account of their higher molecular weights, however, they should be used as 3 per cent. solutions. F. H. L. Two New Colour Reactions for Sesame Oil. J. Bellier. ( a ~ ? ~ ? z . de C'hint, anal., 1899, iv., 217-220.)-0n shaking equal parts of this oil and a reagent consist- ing of sulphuric acid, 100 c.c.; water, 50 c.c.; and formaldehyde (40 per cent.), about 10 c.c., an emulsion is obtained which gradually assumes an inter,se and stable bluish- black colour; whilst with olive, cottonseed, earthnut, poppy, and nut oils the emulsion formed is of a more or less pronounced yellow.B y this ineansit is possible to detect as little as 1 per cent. of sesainJ oil in olive oil even in the case of Tunis oils, which give a relatively dark coloration with hydrochloric acid and furfural, but behave like other pure olive oils with this reagent. The followiug is said to be an equally characteristic test : Two C.C. of the oil areTHE ANALYST, 51 shaken with 2 C.C. of crystallizable benzene saturated with resorcinol, and 2 C.C. of nitric acid free from nitrous vapours (specific gravity 1.38). With sesame oil the mixture assumes an intense bluish-violet d o u r almost immediately, and the acid which separates has an intense bluish-green colour which lasts for five or ten minutes. In the case of olive oil the mixture sometimes remains aolourless, but generally, and especially with Tunis oils, has a more or less pronounced violet tint, while the acid which separates is at first pale yellow and finally orange yellow. Earthnut, cottonseed, poppy, nut, and linseed oils yield an intense violet-blue mixture, but, unlike sesamk oil, do not give a green-coloured acid on the layers sepa- rating, With olive oil containing l per cent. of sesamk oil the green colour of the acid layer is still marked after several minutes. c. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9002500044

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

THE ANALYST, 51 I N O R G A N I C A N A L Y S I S . Solubility of Lead Sulphate in Ammonium Acetate. (A4??zer. L‘herlt. Joimz., vol. xxii. [3], pp. 217, 2lS.)-A series of experiments made show that the maximum solvent effect is exerted on lead sulphate when the ammonium acetate solution is of 31 to 37 “volume per cent,” (29 to 34.3 per cent.) strength; therefore, to dissolve this lead salt, it should be boiled in 10 C.C. (for 1 gramme) of a 33 per cent. solution of the acetate (specific gravity 1*07), and filtered promptly. I t is found that, in recovering the lead sulphate, the evaporation and expulsion of the ammonium acetate without loss is greatly facilitated by an addition of 0.5 gramme of sulphuric acid. c). s. J. C. Long. Analysis of White Metal. H. Nissenson. (Chenz. Zeit., 1899, xxiii., 868.)- Lnder the name of ‘‘ metallic packing ” for engine glands, etc., two classes of alloys are frequently to be met with, containing about SO per cent.of lead with (a) 6 per cent. of antimony and 12 per cent. of tin, or ( b ) with 12 to 15 per cent. of antimony and 3 to 5 per cent. of tin. To analyse them, 1 gramme of the sample is mixed with 2 to 4 grammes (4 grammes for class a, 2 granimes for class b) of tartaric acid, 12 C.C. of water, and 4 C.C. of 1-4 nitric acid, warming till solution is effected. Four C.C. of strong sulphuric acid are then added to precipitate the lead, evaporating in such fashion that the nitric acid is driven off but the tartaric acid not decomposed. To attain this object, the liquid is heated in an Erlenmeyer flask as long as the red vapours are produced; and in order t o watch the process conveniently, the nitrous acid is blown out of the vessel with a tent piece of tubing periodically.Immediately the fresh bubbles of gas are white, the flame is removed; a little water is introduced, and the lead sulphate is collected. The filtrate is made alkaline with sodium hydroxide, 50 C.C. of a cold saturated solution of sodiuni sulphide are run in (any copper thrown down being removed), and the whole is electrolysed a t 80” C. with a current of 1.5 amphes at 3 volts. The liquid is poured off from the antimony, which is rinsed in a little water and dried. The sodium sulphide in the solution is pext converted into ammonium sulphide by treatment with 25 grammes of ammonium52 THE ANALYST. sulphate, and the tin is deposited with the same currentl, and at the same temperature as before.F. H. L. Determination of Chromium in Steel. R. W. Mahon. ( J o M ~ H . A?ner. Che7n. Soc., vol. xxi. [Ill, pp. 1057-1060.)--A modification of McKenna’s method gives good results, 3 grammes of the substance being dissolved in 50 C.C. of concentrated hydro- chloric acid, and boiled down to a moist cake. This is boiled for a few minutes in 50 C.C. of concentrated nitric acid, and, after cooling in the dark, is treated with 4 gramines of potassium chlorate, and concentrated to 25-50 C.C. After dilution to 300 C.C. with water, 15 C.C. of ammonia, specific gravity 0.90, are stirred in, and the (cool) solution passed through a ribbed double filter-paper to remove oxides of manganese.The filtrate and (cold water) washings are made up to about 450 c.c., and titrated with standard ferrous ammonium sulphate and potassium permanganate, preferably standardized by standard potassium bichromate. If the removal of hydro- chloric acid has been completely effected by uitric acid, about 2 grammes of potassium chlorate will suffice to oxidize the chromium present; but this salt is a more con- venient agent than nitric acid for eliminating the final traces of hydrochloric acid. The solution must be dilute and cold, as well as free from too great an excess of nitric acid, in order that reduction of the chromic acid by the filter-paper rimy be prevented. The manganese oxides on the filter may be utilized for the gravitnetric determina- tion of this metal, the precipitate being dissolved in hydrochloric acid, the iron thrown down as basic acetate, and the manganese as manganous aminoniuin phosphate.c:. s. Estimation of Chromium in Iron and Steel. E. Dohler. ( c l i c i i ~ . Zcit., 1899, xxiii., 868.)-When a hydrochloric acid solution of iron is precipitated with bariiim carbonate, not all the chrorniuni is thrown down. the first time ; if the sample contains much chromium (4 per cent.), even a third treatment is necessary to recover it all. 2.5 to 5 grainmes of the iron are dissolved by heating with 30 C.C. OF 1.19 hydro- chloric acid and 100 C.C. of water in a 750 O.C. flask closed with a valve-stopper. The liquid is diluted to about 600 C.C. with cold water, and a crearn of barium carbonate is added until, after half an hour’s standing, an excess is still noticeable. The precipitate, whicli should be slightly yellow owing to traces of iron, is allowed to rest in the well-closed flask for twelve hours, then filtered off through a covered funnel, and the filtrate is treated again with barium carbonate precisely as before. The mixed precipitates are ignited in porcelain with alkali carbonates and potassium nitrate, at first over a Bunsen flame, and finally for half an hour before the blowpipe. The mass is extracted with hot water, filtered froin iron and barium, freed from silica by evaporation with hydrochloric acid, again filtered, and the chrcmiuiii and aluminium separated as usual. Neither silver, nickel, nor platinum crucibles must be used, and a fresh porcelain one should be emploved each time. Too large an excess of barium carbonate is to be avoided, and the substance should be very finely subdivided. 3’. H. 1,.

ISSN:0003-2654    

DOI:10.1039/AN9002500051

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

THE ANALYST. 53 APPARATUS. A Simplification of Beckmann’s Boiling-point Apparatus. S. L. Bigclow. (Amer.. ChenL. JOZLWZ., vol. xxii. [4], pp. 280-287.)-The substitution of electric heating for gas enables the sealed platinum wire, the glass beads, asbestos stove, outer jacket, and its attached reflux condenser, of the Beckmann apparatus to be dispensed with, and also obviates danger arising from breakage and fire in the case of inflammable solvents. I n the drawing, ,4 represents the therniometer, and C,C two mercury tubes for conveying current to the platinum coil D, which is made of 0.1 millimetre wire wound to a diameter of about 1 milli- metre, and measures 1.3, to 2 centimetres in length, the free ends being preferably sealed into the mercury tubes To replace the outer jacket employed by Beckinann, the vessel may be immersed in a battery jar well lined with felt ; a Dewar \-acuuix jacket would, however, be preferable, to facilitate inspection.A current of about 1.8 ampches from an incandescent lamp circuit will boil 30 C.C. of water in five minutes; and 3 cells of a storage-battery furnished the author with good results in the case of readily volatile solvents. Care is necessary to avoid any great perpendicular length of wire at the ends af the coil, or the wire may become enveloped in vapour and grow red-hot. c. 8. Apparatus for determining the Flash-point of Lubricating (Cl~enz. ,%it., 1899, xxiii., 800.)-As shown in the illustration, ling. consists of a copper basin, 50 millimetres deep and 70 millimetres wide, filled with sea-sand, and containing a porcelain crucible to hold the oil, 45 inillimetres deep and 40 millimetres in diameter.The crucible is sunk into the sand till it projects 10 rnillimetres, and it is charged with oil to the same level The shade is made of heat-resisting glass, 250 millimetres high and 100 millinietres in diameter ; it protects the apparatus from draughts, and prevents the igniting flame from being blown out by sudden gusts of air. The main burner is of such power that the oil rises about 20 in temperature in thirty seconds, and tests are made at the same intervals of time, commencing as soon as the sample reaches 20” or 30” below its expected flashing point, A copper lid, provided with a slit for passing over the thermometer stem, and wi$h a handle, is used to extinguish the flame of the burning oil.Oil. R. Kiss- this apparatus P F. H. L.54 THE ANSLY ST. An Asbestos Filter - Tube. 0. Lohse. (L’er., 1899, xxxii., 2142.)--This consists of a piece of combustion tubing 12 centimetres long and 15 millimetres in diameter, expanded for about one-quarter of its length to a diameter of 20 millimetres, and closed like a test-tube at the end of its narrower portion with a hemispherical bottom, which is perforated with a number of small holes. It is charged with asbestos and fixed to a tube funnel for filtrations in the same manner as a Gooch crucible, while the shoulder enables it to be supported safely in a desiccator provided with a suitably perforated tray. The tube can he fitted with a glass stopper, if so desired, and by applying a cork and leading tube to its mouth the contained precipi- tate can be ignited in a current of gas.The author also describes various desiccators of somewhat obvious design, one of which holds caustic potash as well as calcium chloride. F. H. L. An Improved Potash - bulb,” and a Simple Apparatus for estimating Carbon Dioxide by Absorption. R. Schallar. (zcits. c w p v . C h e m , 1899, 878.)- The kind of vessel employed by the author to absorb carbon dioxide is shown by the tube marked V in the annexed illustration. R e claims for it that useful space is raised to a maximum, that useless spacs is reduced to a mi_n,imuni ; that the tube has very little external surface, but a high absorbing power. The wide limb of the LT is half filled with hollow round glass balls about 2 milliinetres in diameter, and it contains about 10 C.C.of 50 per cent. potassium hydroxide. ,4t the top, suspended by means of the tube through which the air passes out of the complete apparatus, hangs a smaJl test-tube 8 centimetres long, filled with 1 C.C. of strong sulphnric acid; the tube whereby the air enters the latter is formed as shown, and extends to just below the level of the liquid. The carbon dioxide enters through the narrow limb of the [J, and travels upwards through tbe moistened bulbs. The illustration as a whole represents apparatus for determining carbon dioxide by treating carbonates with acid in the vessel 111. I and 11, filled like V, free the current of air from carbonic acid ; I V is a drying tube similarly filled with sulphuric acid. The joint at the Iunnel is made with a tapering glass tube which enters the parallel funnel-tube ; it is rendered air-tight by a water-seal.The current of air is aspirated rather than driven through the apparatus ; and to ensure regularity of passage, either the final exit tube or both the exit and the first admission tubes are contracted to a fine point. The manipulation is obvious. F. H. L. For exact work V is used in duplicateTHE ANALYST. 55 Platinum Gauze as a Cathode for Electrolytic Analysis. C. Winkler. (Bey., 1899, xxxii., 2192.)-A piece of platinum gauze 10.5 centimetres long by 5.5 centimetres wide, composed of wires 0.12 millimetre in gauge, and with 250 meshes per square centimetre, has its edges bent over for a width of 2 or 3 milli- metres so as to strengthen it, and is then coiled into an open (C-shaped) cylinder 5 centimetres high by 3-5 centimetres in diameter, leaving a slit 5 millimetres wide for the insertion of the anode.This form of cathode weighs only 13 grammes, and is capable of bearing its own weight of copper without any danger of the deposit falling off when washed. Much higher current-densities can be employed than formerly, reducing the time required to electrolyse a solution to about one-quarter of its usual length. Copper may be safely thrown down from its sulphate with a current of 0.5 ampere (density, D1,,, = 5.1 amphes), and 13 grammes can be deposited in sixteen or eighteen hours. Very gratifying results have also been obtained with silver, nickel, cobalt, zinc, and antimony.F. H. L. A Dissolver. A. J. Hopkins. .4~no~. Chenz. JO~WW., vol. xxii. [ 5 ] , pp. 407-410.)-An ordinary glass cylinder of suitable capacity may be used, that shown in the figure holding 2,200 C.C. A straight 6-niillinietre tube is passed through one hole in the stopper, and connected below with a Y-tube, the other upper limb of which is connected to an upcast tube, bent over at the top above the surface of the dissolving liquid. When the cylinder is charged with solvent and the salt to be dissolved, air is drawn through the apparatus by an aspirator connected with the short bent tube on the right, and the inflowing current carries up with it from the Y-tube small columns of the saturating solution drawn through the lower limb, which are discharged at the top and are automatically replaced by fresh portions of the solvent descending the cylinder. The apparatus is very rapid in action, 30 grammes of copper sulphate having been dissolved in 200 C.C. of water at 19" C. in forty minutes; and with a, larger cylinder 1 kilo of ammonium carbonate wafi dissolved in 4 litres of water and 1 litre of ammonia in about half an hour. c. s. h i I 1 I I I L: c I %I I I I I 1 * I i G I - I

ISSN:0003-2654    

DOI:10.1039/AN9002500053

出版商:RSC    

年代:1900

数据来源: RSC

摘要:

56 THE ANXLY ST. SALE OF FOOD AND DRUGS ACT. (Ileprinted jrom the ‘( Times ” of February I, 1900.) THE Right. 11011. TT. 13. L o n ~ , M.P., President of the Board of Agriculture, has appointed a departiiiental coniinittee to inquire and report as to what regulations, if any, may with advantage be made by the Board of Agriculture under section 4 of the Sale of Food and Drugs Act, 1899, for determining what deficiency in any of the normal constituents of genuine rnilk or cream, or what addition of extraneous matter or proportion of water, in any sample of milk (including condensed milk) or cream shall, for the purposes of the Sale of Foods and Drugs Acts, 1875 to 1899, raise a presumption, until the contrary is proved, that the milk or cream is not genuine. The committee will consist of the following gentlemen, viz., Lord Wenlock, G.C.S.I., G.C.I.E. (chairman), Mr. George Barham, Mr. George Cowan, Major Patrick George Craigie (an assistant secretary of the Board of Agriculture), Mr. S. W. Farmer, Nr. Shirley P. Murphy, 11 D., Prof. Thorpe, F.R.S. (Principal Chemist of the Govern- ment Laboratories), and MY. J. Augustus Voelcker, 1’h.D. hlr. Robert Henry Rew, of the Board of Agriculture, m7ill act as secretary to the committee.

ISSN:0003-2654    

DOI:10.1039/AN900250056b

出版商:RSC    

年代:1900

数据来源: RSC