摘要:

AN IMPROVEMENT IN THE METHOD OF SEPARATING ZINC FROM NICKEL BY SULPHURETTED HYDROGEN I N A 4 SOLUTION CON- TAINING GALLIC ACID. BY ERNEST A. LEWIS. (Read at the Meeting, December 3, 1902.) I HAVE recently made some experiments to see if a more reliable method of separating zinc from nickel could be devised than those which are usually used. The separation of zinc from nickel in a solution faintly acidified with HC1 never gives accurate results, as the zinc sulphide always contains appreciable amounts of nickel and the zinc is seldom completely precipitated, and it is well known that zinc sulphide is one of the most difficult precipitates to wash owing to its tendency to give turbid filtrates. Methods involving the use of cyanides and sulphocyanides are objectionable owing to the poisonous nature of the vapour of prussic acid that is94 TEE ANALYST.liberated. The succinic acid method is not satisfactory, as it is necessary to have a saturated solution of the succinic acid, which sometimes crystallizes in the filter when filtering off the zinc sulphide. I have found that if tg a neutral or faintly acid (with H,SO,) solution of zinc and nickel, containing from 0.3 gramme to 9.6 gramme of each metal, 2 grammes of gallic acid dissolved in hot water be added, and then H,S passed through the perfectly cold and diluted solution, the zinc is precipitated as perfectly white sulphide not containing a trace of nickel. The zinc sulphide settles readily, can be filtered through a single Swedish filter-paper, and washed easily and rapidly; the filtration and washing seldom take more than half an hour, the filtrate is perfectly clear, and contains the whole of the nickel.The details of the method are as follows: To the solution of the two metals containing not more than 0-6 gramme of each, preferably in sulphate solution, sodium carbonate solution is added until a faint precipitate persists in the solution on stirring ; this is dissolved by adding a drop of dilute sulphuric acid. The solution is diluted to about 300 C.C. with cold water, 2 grammes of gallic acid dissolved in water are added, and the solution mixed ; a fairly rapid current of H,S is passed through the solution for half an hour, after which it is filtered through a single Swedish filter- paper, the precipitate washed four or five times with cold water, and then dried in the steam-oven.The precipitate is transferred as completely as possible to a Rose crucible, the paper, burnt to a complete ash in a coil of platinum wire, is then added, the precipitate, sprinkled with a, little pure sulphur, ignited over a Bunsen flame for five minutes in a current of purified dry hydrogen, and weighed as ZnS. The nickel may be estimated in the filtrate from the zinc sulphide as follows, but the instructions given must be carefully carried out, or low results will be obtained : The solution is evaporated down in an open beaker on a hot-plate until it is reduced to about 15 C.C. ; the cover is then replaced on the beaker, which is taken from the hot-plate and allowed to cool; 30 C.C. of strong HNO, are added, and the cover is kept on the beaker, which, when the first effervescence has ceased, is replaced, still covered, on the hot-plate.The solution, which is dark brown, is boiled until it again becomes green; the cover is then rinsed, 1 C.C. of H,SO, added, and the solution boiled down almost to dryness in a 6-inch porcelain dish on a water- bath. It is heated over gauze with a Bunsen burner until the sulphuric acid is volatilized, then more strongly to decompose the small amount of organic matter left, allowed to cool, the residue boiled with water containing a little sulphuric acid, and filtered. The filtrate received in a 500 C.C. Jena glass beaker; the residue is washed once with dilute sulphuric acid, and then four times with water ; 10 C.C. of strong ammonium hydrate are added, then 3 grammes of ammonium oxalate dissolved in water, and the solution is diluted to about 300 C.C.It is heated to about 40" C., and electrolysed with three Bunsen cells or their equivalent. The solution is kept at about 40" C. during the electrolysis, which is complete in three or four hours, the end of the process being ascertained by the addition of ammonium sulphide in the ususl manner. The platinum cone is well washed, first with cold water and then with alcohol, dried in the steam-oven, and weighed. Care must be taken that all the alcohol is driven off; sometimes the nickel deposit is onlyTHE ANALYST. 95 1 2 3 free from alcohol after drying for half an hour. This method gives very accurate results if the above instructions are carefully carried out.Unless, after the evaporation with sulphuric acid, the mass of nickel sulphate and organic matter is thoroughly charred, the organic matter will contain from 10 to 30 milligrammes of nickel, which cannot be washed out; hence the necessity for strongly heating after the sulphuric acid is driven off. The addition of ammonium oxalate causes the nickel to form a silvery deposit, and not a black deposit as when ammonia only is added. The following results were obtained in sulphate solution : Gramme. ! Gramme. a2999 1 - -2999 I -2975 *1199 -1190 i5IX.C. _ _ _ - -~ - -- I No. 1 Taken, 1 Found. I I - -- _ - - - -__I ~ _ _ ' ~ Gramme. I Gramme. 1 *2714 a2701 2 -3097 3 ~6194 4 -4045 5 -1300 6 a9291 7 -3251 8 *3251 -3096 -6195 -4032 -1304 -9287 -3248 ,3267 __ Error.- -0013 - -0001 + -0001 - -0013 + *0004 - ~0004 - -0003 + -0016 NICKEL. Taken. Found. about -3 gramme t l 9 9 7 , 7 , -1210 -1188 ~3065 el219 Error. I n Nos. I to 5 the nickel was from 10 to 30 milligrammes too low, owing to the The following results were obtained in 8, organic matter not having been destroyed. nitrate solution : - __- ~ ~ _ _ _ _ -~ - i I' ZINC. NICKEL. No. ' Taken. ~ Found. 1 Error. I' Taken. -__ /I - I 1 - 1 . ~ _ _ _ 'I Gramme. I - 1 Gramme. 1 Gramme. 1 1 1 -2985 -2962 - ~0023 -2671 2 1 -2985 -2960 - -0025 *I085 3 , -1194 a 1 1 8 3 1 -.0011 11 -2671 - i I - ~- And the following in a chloride solution : Found. Gramme. ~2674 -1098 -2666 Error. -b -0003 + -0013 - *0005 ZINC. NICKEL. I Gzrag. 1 Gramme. 1 - ,2146 I -*0023 -0867 *Of364 1 -*0003 -2160 1 -*0009 I - *000996 THE ANALYST.*3251 1 -3322 1 Cobalt I -4042 -3251 1 *3250 ' I Iron 1 -3204 -3251 a3277 , Aluminium i -2922 -3251 -3245 1 Manganese 1 ~4716 I I have also made experiments to see if zinc could be separated from cobalt, iron, aluminium, and manganese in a neutral solution containing 2 grammes of gallic acid. The following results were obtained : -403 -3213 -2919 ~4719 . -___ Metal. Zinc Zinc Zinc Zinc Taken. I Found. 1, Metal. Taken. Found. I/ I Gramme. 1 Gramme. ~- --_____-- I Gramme. I Gramme. I t is seen from these experiments that iron, aluminium, and manganese are com- pletely separated, but a little cobalt is precipitated with the zinc. The zinc sulphide had a greenish colour. For the analysis of German silver and similar alloys about 1 gramme of the alloy is treated with nitric acid, the excess of acid boiled off and the solution diluted.Any tin oxide is filtered off. The filtrate is diluted to 300 c.c., and 5 C.C. HC1 added. H2S is passed through to precipitate copper and lead; the sulphide precipitate is redissolved, reprecipitated with €&S, and filtered ; the copper being estimated volunietrically or electrolytically. The filtrates are boiled down to dryness with sufficient H2S0, to convert the zinc and nickel into sulphates. The solution is taken up with water, neutralized with Na,CO, till a faint precipitate persists in the solution, then 1 drop of dilute sulphuric acid is added to redissolve the precipitate and 2 grammes of gallic acid. The solution is diluted to 300 c.c., and the zinc precipitated as sulphide; the retnaindsr of the process being conducted in the manner described above.As these alloys seldom contain more than small amounts of tin, lead, iron, aluminium, manganese, and cobalt, these metals are best estimated in a separate portion, using 5 gramrnes of the alloy. In order to see if small amounts of nickel could be separated from comparatively large amounts of zinc, I took a solution containing about 3 grammes of zinc with 0.0245 gramme of nickel, added 8 grainnies of gallic acid, and passed H,S to satura- tion; filtering off the zinc sulphide. The filtrate was boiled down and the gallic acid destroyed with 70 C.C. of HNO,, followed by evaporation to dryness with 1 C.C. of H,SO, and the strong heating of the residue.The residue was redissolved in water containing a little dilute H,S04 neutralized with Na2C0,, 1 drop of dilute H2S0, added, 2 grammes of gallic acid, and H,S again passed ; a small amount of ZnS came down, which was filtered off, and the filtrate again evaporated with HNO, and H,SO,. The residue was taken up with water containing a little H,SO,, filtered, and electro- lysed after adding ammonia and amnionium oxalate; 0-0254 gramme nickel was found. This method can, therefore, be used for estimating the small amount of nickel usually present in commercial brasses by taking 7 grammes of brass, separating the copper with H,S, and then evaporating with sufficient H,SO, to convert the zinc, etc., into sulphates, separating the zinc by a double precipitation with H2S, asTHE ANALYST.97 described above, and estimating the nickel and iron in the filtrate. Messrs. L. E. Dance and L. J. Meyrick, have assisted me in these experiments. My assistants, DISCUSSION. Mr. ALLEN said that, while the use of a fixed organic acid like gallic acid certainly effected complete separation, trouble would probably arise, as the author had himself found, unless great care was exercised. He (iMr. AIlen) had used habitually two processes for the separation of zinc frorn nickel in alloys. Formerly he used to convert the two metals into double cyanides, then passing sulphuretted hydrogen, and obtaining ii perfectly white, slimy precipitate of pure sulphide of zinc, which was difficult to treat afterwards, requiring to be redissolved and being difficult to wash.For many years past he had used a process devised by Mr. Thomas Bayley, in which, after neutralization of the solution with sodium carbonate (ammonium salts must not b? present), twice its bulk of ordinary acetic acid was added, sulphuretted hydrogen being then passed throagh the liquid. The sulphide of zinc came down, not in a slimy condition, but as a granular precipitate, which was easily filtered. The nickel in the filtrate was present as sulphnte, and it was only necessary to evaporate the liquid in order to get rid of all the acetic acid, when the nickel could be determined without difficulty by any of the ordinary methods. The sulphide of zinc could be treated with sulphuric acid and converted into sulphate, which was the most convenient form in which t o weigh either zinc or nickel. A larger weight was obtained, and either sulphate would with- stand a dull red heat without decomposition, though in the case of nickel an obvious change to black oxide took place if overheating occurred. Zinc sulphate, however, was not so readily decomposed by heat. He had used to a limited extent the sulphocyanide process. The zinc came down quite well in an acid solution to which potassium sulphocyanide had been added ; but in this case also difficulty arose owing to the presence of another fixed organic acid-namely, free thiocyanic acid. The separation, however, was good.

ISSN:0003-2654    

DOI:10.1039/AN903280093b

出版商:RSC    

年代:1903

数据来源: RSC

摘要:

THE ANALYST. 97 NOTE ON THE ESTIMATION OF SULPHUR I N PIG-IRON. BY CLARENCE A. SEYLER, B.Sc., F.I.C. ( R e a d at the iYeeting, December 3, 1902.) THE following notes are the result of a few experiments primarily made to ascertain the best conditions under which the evolution method for the estimation of sulphur in pig-iron can be performed. I have to apologize for their incompleteness and the absence of any very definite conclusions. There are so many conditions which have t o be varied one at a time that the complete investigation of the subject requires an enormous number of experiments. The evolution method seems to be fairly satis- factory for steel; for pig-iron, however, the results are, as is well known, too low. The two chief reasons being that, firstly, some sulphur remains in an insolubie form in the residue of the attack ; secondly, part of the sulphur is evolved in the form of organic compounds which are not precipitated by the reagents for hydrogen sulphide,98 THE ANALYST.nor are they oxidized by bromine to sulphates. The latter defect can, it is claimed, be overcome by passing the gases, mixed with excess of hydrogen, through a porcelain tube heated to ‘( bright redness.” This involves a greater complexity in the apparatus, as well as an increase in the length of the time required for the experi- ment. A very attractive suggestion has recently been tested by G. T. Dougherty (Ch. N., 1902, vol. Ixxxvi., p. 28). This consists in simply annealing the sample by heating it in a porcelain crucible, with a piece of filter-paper to give a non-oxidizing atmosphere, to the full heat of a good Bunsen burner, cooling slowly, and proceeding with the evolution method in the ordinary way.The results given for low sulphur contents are very satisfactory. I n the following experiments the sample of iron was a white pig-iron, rich in sulphur and phosphorus. The total sulphur was very carefully determined by the oxidation method with aqua regia, as described by Blair and also by Bamber’s method.::‘ Both methods are somewhat tedious, and require a special correction for impurities in the reagents, and are not suited for rapid work. For the most accurate work I prefer Bamber’s method, as the total sulphur is obtained, and the precipitation is made in a solution free from iron. The aqua regia method gave 0,172 per cent.of S against 0-174 by Bamber’s method. The first series of experiments was made with the apparatus commonly used in American steel works--an evolution flask with tap funnel, but without condenser, no current of hydrogen being used to sweep out the gases, the contents being simply boiled until the water began to condense in the receiver, which W ~ R a Varrentrap nitrogen bulb. The absorbent used was a solution of potash, which, after being largely diluted, was acidulated with HC1 and titrated with standard iodine. An ammoniacal solution of cadmium chloride did not appreciably alter the results, which, though low, were consistent. The action was continued until all iron was apparently dissolved, though this was difficult to determine.The period of action was about thirty minutes, first in the cold, then with gentle heating, and finally boiling. Under these conditions dilute acid (equal volumes of strong acid and water) gave only 0.111 per cent. sulphur on the non-ignited sample. Igniting the sample increased the results slightly, giving 0.125 per cent. Strong acid did not improve the results on the non-ignited sample, but ignition raised them (with strong acid) to 0.142 per cent. Passing the gases mixed with hydrogen still further raised the results to 0.150 per cent. This maximum result is still, however, 0.02 per cent. below that of the oxidation method, and the deficit was found in the residue. It was ascertained that the increase of sulphur on ignition did not arise from absorption of sulphur from the coal-gas used in heating the muffle.Stronger ignition for fifteen minutes over the blowpipe caused a large loss of sulphur. With the above apparatus the results under any given conditions were consistent, and it seemed that the use of strong acid, as well as the ignition, were essential to * In Bamber’s method, 5 grammes of the sample are dissolved in 40 C.C. strong nitric acid, and 2 to 5 grammes of potassium nitrate added. The solution is evaporated to dryness in a platinum dish and ignited, ground up, treated with water containing a little sodium carbonate (0.5 per cent. solution free from sulphur), acidulated with hydrochloric acid, evaporated to dryness, filtered, taken up with water, heated to boiling, and precipitated with barium chloride.THE ANALYST.99 secure anything like an approach to approximate results. On altering the apparatus and using a current of hydrogen without a condenser, the results, to my surprise, became inconsistent. They varied from 0.124 to 0.136 per cent., and the use of strong or dilute acid or ignition made no improvement in the results. This was at length traced to the fact that the current of hydrogen (which was in every case purified by passage throagh silver nitrate) carried forward so much steam that the potash solution became hot. The use of a condenser at once raised the results to 0.14 per cent., the action being continued for an hour or more. Under these con- ditions the results with dilute or strong acid were the same, ignition making very little improvement.This seems to show that the low results previously obtained on the non-ignited sample were due to incomplete solution, the effect of the ignition being to cause the ignited sample to dissolve more completely in strong acid ; the evolution of the sulphur is then more rapid, and better results are obtained. My experience is, however, very unfavourable to the use of potash as an absorbent if the solution has to be titrated. This absorbent, which is recommended by Blair and is used by some American chemists, is preferable to the ammoniacal cadmium solution, because it is more easily washed out of the receiver, and affords a greater rapidity and sharpness in the end reaction. The end-point is slowly reached with cadmium; nevertheless, the use of potash is attended with the danger of obtaining low results if the solution is allowed to get hot.Direct experiment with known amounts of hydrogen sulphide received in potash showed that prolonged heating to a moderate degree reduced the results, and that they were uniformly lower than those obtained by titrating in the presence of cadmium. For these reasons the use of potash was abandoned, and the gases absorbed with bromine, Ledebur's apparatas, in which the gases pass through a long column of glass beads, moistened with brominated hydrochloric acid, being found superior to the Varrentrap bulb for the absorption. Using this apparatus, the non-ignited sample, without the aid of the furnace, gave 0.135 and 0.143 per cent. Ignition for a quarter of an hour raised the results by about 0.02 per cent.Ignited at 700" C. ... ... ... ... 0.154 ,, 750" C. ... ... ... ... 0.162 ,, 800" c. ... ... ... ... 0.154 This is still below the true amount. On the other hand, passage of the gases through a porcelain tube, heated to about 750' C., gave 0.172 and 0.174 per cent., thus approaching the actual amount of sulphur present, A few experiments upon a fresh sample gave results more favourable to the ignition method. The oxidation method gave 0.183 per cent., and passage of the gases (from the non-ignited sample) through the red-hot tube gave 0.186 per cent. This sample when not ignited gave in two experiments 0.154 and 0.151 per cent, of sulphur, while after ignition for a quarter of an hour to 750" C. strong hydrochloric acid expelled 0-184 and 0.187 per cent., thus practically agreeing with the oxidation method. Further experiments are needed with different kinds of iron, especially with a view to determining the best temperature for the ignition.The method with ignition is certainly, however, an improvement on the evolution process.100 THE ANALYST. The results hitherto obtained point to the following conclusions : 1. The use of strong hydrochloric acid is advisable in the evolution method. 2. Ignition to about 750' C. for a quarter of an hour approximately raises the results of the evolution method until they are nearly equal to those of the oxidation method. 3. The use of potash as an absorbent in the volumetric estimation of sulphur leads to low results, especially if the condenser be omitted.4. Passage of the gas, mixed with hydrogen, through a red-hot tube gives good results if strong hydrochloric acid is used. Finally, I wish to acknowledge the assistance of Mr. Sidney Crook in carrying out these experiments. DISCUSSION. Mr. ALLEN said that a difficulty which sometimes existed in connection with processes for the determination of sulphur and other constituents in iron and steel was that, while they worked very well with one particular class of metal, they were inapplicable to others. The disadvantage to which evolution processes generally were subject was the possibility that a certain proportion of the sulphur might be left behind in the evolution-flask. When once the sulphur was completely evolved in the form of hydrogen sulphide gas, there was no difficulty in its estimation.One source of dis- crepancy in sulphur determinations in pig-iron was the tendency of the sulphur to segregate itself together with the graphite. This occurred to a considerable extent in the case of gray pig-iron, and very careful preparation of the sample was neces- sary in order to avoid discrepant results. I n speaking of hydrochloric acid, he did not quite understand what meaning the author attached to the term '' strong acid." He (Mr. Allen) used that term to indicate, not fuming acid, but acid that distilled without change, having a specific gravity of about 1.11. That was the sense in which the term was used by Fresenius. It seemed desirable, in referring to any particular strength of acid, to express it in terms of specific gravity, and so avoid any possibility of misunderstanding.He hoped, too, that some mode of description of temperature might be used which was more definite than '' cherry-red " and similar expressions. Mr. JENKINS inquired whether the shortage obtained in the evolution method was confined to cast-iron or whether it extended also to mild steel, which would be a more convenient substance to experiment with. He had been struck by the apparent advantage attending the heating of the iron as a preliminary to the sulphur estimation ; and it was curious that the minimum temperature which Mr. Seyler had found to be advantageous-namely, 750' C.-practically coincided with the tempera- ture at which, in mild steel, there was a radical alteration in the structure and character of ths steel-there was a breaking up of the pearlite areas, the carbon from which diffused out by a process akin to cementation, and the iron itself also underwent an allotropic change at about the same temperature.I t was curious that the alteration in the condition of the sulphur took place at practically the same temperature as this general series of changes, and it might be of interest to ascertain whether any difference were found between the results of a sulphurTHE ANALYST. 101 estimation by the evolution method in a mild steel that had been annealed and in the same steel which had been quenched from a high temperature, in which latter case both the carbon and the iron would be in an abnormal condition corresponding to these high temperature changes.Mr. SEYLER, in reply, said that the idea of annealing the sample had attracted him owing to the fact that apparently the whole of the sulphur was evolved from the residue and passed in some form or other into the gas, and, in his view, that constituted the sole merit of the process, for an evolution method was obviously useless if the whole of the sulphur did not come off in the first instance. Whether the sulphur was evolved entirely in the form of sulphuretted hydrogen, or whether a portion was still in the form of carbon compounds, he was not quite certain, but he imagined that a certain proportion must still be in the form of carbon compounds. When referring to strong acid he had meant acid having a specific gravity of 1.16, such as was commonly sold as (' strong acid." He agreed with Mr. Allen in objecting to such terms as " cherry-red " ; but all the temperatures he had referred to had been determined by Le Chatelier's thermo-couple. The temperature in the red-hot tube was 750" C. I t was well understood, however, among those who worked with high temperatures, that the term '' cherry-red " indicated a temperature of about 800" C. ; and Le Chatelier gave corresponding temperatures for the various descriptive terms, so that no doubt need exist as to their approximate signification. In the case of mild steel the evolution method had been found fairly satisfactory. As a rule, there seemed to be much less difficulty in getting all the sulphur evolved from steel than from pig-iron, especially cupriferous pig-iron.

ISSN:0003-2654    

DOI:10.1039/AN9032800097

出版商:RSC    

年代:1903

数据来源: RSC

摘要:

THE ANALYST. 101 NOTE ON PURE AND COMMERCIAL CIVET. BY HERBERT E. BURGESS. (Read at the Meeting, December 3, 1902.) CIVET is of considerable value in perfumery as a fixing agent, and this may be due to the fact that its chief constituent is a fatty acid which is only slightly volatile. I n appearance it is of a light-brown colour, having a consistency similar to Vaseline, and is unctuous to the touch. I have taken every precaution to obtain samples of whose purity there can be no reasonable doubt, and have had placed at my disposal a small amount of civet which has been actually obtained from the cats kept by a large firm. Other samples-Nos. 1 and 2-have been obtained from the Zoological Gardens, Regent’s Park. These samples, although undoubtedly pure, differ somewhat from commercial civet, inasmuch as the secretion has been deposited on the sides of the cage and allowed to stand some considerable time.Consequently it is much dryer than com- mercial civet, which is taken from the pouches of the animals by means of a spoon. No. 3 is a sample obtained from a reputable firm in London, and invoiced as Absolutely Pure Civet.”102 THE ANALYST. No. 4, ordinary commercial civet. No. 5, pure civet, own extraction. On examination under the microscope it is always found to contain hair, wood- On distilling samples Nos. 1 and 2 with steam practically no oil This was insufficient On heating the civet to constant weight in a water-bath, which took twenty-four pulp, sawdust, etc. distilled over, but with Nos. 3 and 4 a few drops distilled over. for further identification.hours, the following results were obtained : Ash. Moisture and Volatile Matter. Per Cent. Per Cent. No. 1 ... 6.3 ... ... ... 2.7 No. 2 ... 4.5 ... ... ... 3.1 No. 3 ... 27.0 ... ... ... 2.1 No. 4 ... 12.3 ... ... >.. 1.1 No. 5 15.9 ... ... ... 3.3 ... The ash was dissolved in HCl, when a considerable amount of GO, was evolved. The insoluble portion was found to consist chiefly of calcium carbonate. I t contained aluminium, potassium, and magnesium, with chlorides and sulphates, also a con- siderable amount of SiO,. In the examination of civet, extraction with acetone and chloroform and titration of the resulting extract probably enables the most reliable opinion to be formed as to its purity. The method I adopt is to weigh out about 5 grammes of the civet into a tared filter thimble and extract with about 150 C.C. of chloroform, using an enclosed Soxhlet extraction apparatus, repeating the operation on another 5 grammes, using acetone as a, solvent.In cases where only a small amount of the sample is available for examination the acetone extract will give the more valuable information as to its purity, and this for reasons that will be apparent later on. RESULTS OF EXTRACTS. Saponification Number. Acetone. Chloro- Saponification form. Number. - - No. 1 ... 75.8 (43.1) No. 2 ... 75.35 (45.1) 69.6 (61.0) No. 4 ... 83.0 (113.8) 79.6 (112.0) No. 3 ... 43.6 (114.2) 47.2 (113.0) The amounts of residue found in the thimbles is shown in the following table : Acetone Saponifi- Chloro- Saponifi- Ash.cation Residue. form cation Residue. Extract* Number. Extract. Number. H,O, etc. - - 75.8 43.1 - No. 1 6.3 2-7 - No. 2 4.5 3.0 69.6 61 27.2 75.4 45.0 - No. 3 27-0 3.5 43-6 114 28.9 47.2 113.0 23 No. 4 12.0 1.1 79.6 112 4.7 83-0 114.0 33 No. 5 15.9 3 *3 60.0 33 21 *oTHE ANALYST. 103 Commercial civet has been found to be adulterated with butter, lard, soft soap, and various other fats, and quite recently vaseline has been found to be often used for purposes of sophistication. I am indebted to Mr. E. J. Parry for the following method of detecting this substance in a quantitative way, and have found that it worked in a fairly satisfactory manner with samples containing definite amounts of vaseline. The method of procedure is as follows: About 5 grammes of the civet are treated with 50 C.C.of acetone in the cold. After thorough mixing, it is filtered by suction, and washed with another 50 C.C. of acetone. After allowing to drain some time, the mass is removed from the filter-paper, transferred to a small beaker, treated with 50 C.C. of light petroleum spirit, filtered into a tared flask, and washed with a further quantity of petroleum spirit until the washings leave no residue on evaporation. I t is desirable to add a considerable amount of the spirit when samples containing large percentages of vaseline are examined, otherwise filtration is very slow. The spirit is then distilled off and the residue dried and weighed. I t is necessary to test the presence of vaseline by one of the usual methods, but, as bodies having a saponification number are almost invariably used to adulterate this substance, a titration with KOH will usually give a good idea as to the nature of the residue ; in fact, when vaseline has been used, I have generally been able to separate it in a fair state of purity by this method.Sample No. 1 gave by this method 4 per cent. of petroleum extract having a saponification number of 81, whereas sample No. 3 gave 11 per cent., having a saponification number of 95, and the same sample with 2 per cent. vaseline gave 12.7, a difference of 1.7 per cent. having a saponification number I may here quote a few determinations made by Mr. Parry by this method, which of 74.8. show that concordant results may be obtained. COMMERCIAL ADULTERATED SAMPLES. GENUINE CIVET.Vaseline found (two determinations). 3.26 3.40 3-22 3.10 3-12 3-30 4.06 3-94 6-04 6.3 9.95 9.88 6.4 6.2 5.3 5.14 4.02 4.24 6-00 6.14 7.24 7.02 2.2 1.90 2.4 2.20 1.9 1.8 4.82 4.6 3.3 3.55 0.3 0.4 0.25 0.3 I have made nitrogen determinations by the Kjeldahl method, and have found that civet contains about 1.3 per cent. of nitrogen, but I have not investigated the nitrogen-containing substance in order to determine its nature.104 TEE ANALYST. A. Hebert (Bull. SOC. Chem.) states that he has found skatol present. I have to thank Mr. T. H. Page, B.Sc., for assistance in the analytical have been unable to confirm. the paper. DISCUSSION. This I work of Mr. HEHNER inquired whether any knowledge existed as to the nature of the That it was a fatty acid, as the author had odoriferous substance in the civet. suggested, seemed improbable. Mr. CHAPMAN inquired what would be the effect of neutralizing the fatty acid. Mr. ALLEN said that it was interesting to bear in mind that some fatty acide (butyric acid and valeric acid, for instance) had distinct odours which were attractive to cats. It would be interesting to know the combining weight of this fatty acid, and whether it approached that of caproic or veleric acid, or whether it was one of the higher homologues. Mr. BURGESS, in reply, said that as yet nothing was known as to the constitution of the odoriferous substance, but he himself thought that it was undoubtedly the fatty acid he had referred to. The odour persisted when the acid was neutralized, and also after it had been converted into its potassium salt. He had not attempted to determine the combining weight of the acid, but he knew that it had a high boiling point.

ISSN:0003-2654    

DOI:10.1039/AN9032800101

出版商:RSC    

年代:1903

数据来源: RSC

摘要:

104 THE ANALYST. ON THE DETERMINATION OF GLYCEROL IN CRUDE GLYCERINES. BY J. LEWHOWITSCH, Ph.D. (Read at the Meeting, February 4, 1903.) THE two methods recognised as the best for estimating quantitatively glycerol in crude glycerine are the acetin method and the bichromate method, the latter especially in the form given to it by Hehner.‘;’ Whilst, personally, I favoured the former method, I did not dispute the accuracy of the latter. I may be allowed to quote what I wrote several years ago in my ‘‘ Chemical Analysis,” p. 808 : “Hehner has shown by a number of comparative experiments, using both the acetin and the bichromate processes, that the results agree very well. This has been borne out by a large number of experiments made by the writer.” In the course of the last few years, however, a number of crude glycerines came into my hands in which the agreement between the two methods was not of a satisfactory kind throughout. It was soon noticed that discrepancies between the two methods occurred in the case of those glycerines which contained somewhat considerable quantities of organic impurities.I give in the following table a number of analyses in support of my contention : * Joum. SOC. Chem. Ind., 1889, 5.THE ANALYST. 105 Acetin Method. TABLE I. Comparison of the Acetin and Bichrornate Methods for Determining the Percentages of Glycerol in CrzLde Glycerines. 1896-1897. Bichromate Method (Copper Sulphate). NO. Description. 1 2 3 4 5 6 7 8 9 10 Soap lye crude Chemically pure Soap lye crude Candlemaker’s crude Soap lye crude 7 7 7 7 77 7 7 7 9 7 7 7 ’ 7 7 ‘ 7 7 7 ’ 7 7 ) 9 ) 7 7 -77 86.66 86.15; 86.06 75-02 99.04; 99.17 80.51 ; 80.66 78-93 85.94 67-76 79-84 83.05 ; 83-07 86.45 86.01 ; 86.34 75-38; 75.10 101.00 ; 101.90 80.37; 80.04 79.41 85.43 67.67 79.23 83.99; 84-65 1900.No. I Description. Bichromate Method (Copper Sulphate). Acetin Method. Candlemaker’s crude Soap lye crude 89.91 ; 90.75 ; 90.43 78.48; 78.65; 78.89 80.46 ; 80.82 ; 80.28 ; 80.61 76.56; 77-45 90.69; 90.74 86.26; 86-16; 86.22 8 1 ; 44; 81.19 94.02; 94-12 93.68 ; 94.21 ; 94.71 ; 94.90 81-42; 81-60; 81.23 82.56 ; 83-03 ; 83.23 ; 83.89 79.36; 79.01 92.70; 93-08 89-70; 89-22 82.51; 82.61 97-21; 97.94 9 9 7’ 7 ’ 7 7 ’ 9 Y P Candlemaker’s crude 7 9 7 7 I Soap lye crude 8 Candlemaker’s crude 1901 - 1902. Bichromate Method (Copper Sulphate).Bichroina te Method (Silver Carbonate and Lead Subacetate). NO. Description. Acetin Method. 1 2 3 4 5 6 9 7 7 8 9 10 Candlemaker’s crude Soap lye crude 7 7 9 ’ 2 7 7 7 ? 7 7 ’ 7 9 ’ 7 7’ 7 7 ’ ? 7 7 Same crude, concen- Soap lye crude Candlemaker’s crude Soap lye crude Candlemaker’s crude trated further 83.51 ; 83.68 81 -42 79-13 75.20 72.98 72.01 74.73 77-31 83.1 ; 82-98 76.53; 76.61 85.23; 85-42 89-44; 89.73 82-21 8152; 81.94 7 8.79 76.04 77.44 78.35 77.96; 78-60 83.9; 83.56; 83.52 78.17 ; 78-24 86.72; 86.41 78.30; 78-33; 78.69 79.25 ; 79-53 -106 THE ANALYST. Where agreement occurs the glycerine was fairly pure ; in the other instances this was not the case. The fact that I did obtain concordant results for a number of years is seen by a glance at the first series of figures, and this fact disposes at once of a possible objection that the bichromate method has not been carried out as directed.I may say that I found it more convenient to use copper sulphate and caustic potash for purifying the crude glycerine than silver oxide and lead subacetate, or, preferably (acting on a private communication from Mr. Hehner), silver carbonate and lead subacetate. In order to invalidate any objection on that score, some of the samples were treated side by side with copper sulphate, and with silver carbonate and lead subacetate. Curiously enough, the results obtained with the help of the latter reagents are a little higher, a fact which Richardson and Jaff6 also have noticed (Journ. Xoc. Chem. Ind., 1898, 332).I may point out that this is not due to an error caused by the larger volume of the precipitate obtained with silver carbonate and lead subacetate. Of course, if the volume of the precipitate should be somewhat considerable, it is imperative to filter off and fill up the filtrate to a known volume. The duplicate tests, I may distinctly mention, were all done with separately weighed quantities of the samples. I think that the numbers given in the table warrant me in uttering a note of warning against the exclusive use of the bichromate method. It is true Hehner advises using both methods in the examination of a sample, and taking the mean of the two results. As to this suggestion, I remarked some years ago that it entails too much work in commercial analysis, and that it is therefore preferable to make two tests by the acetin method.If Hehner's suggestion be adopted, such large discrepancies as I have shown to occur will no doubt lead the analyst to entertain serious misgivings as to the accuracy of one of the two methods, or possibly of both. I for one adhere to the acetin method as the more accurate one, and if attention is paid to all the details, very concordant results indeed are obtained in duplicate tests. Unfortunately, the acetin method lends itself only to fairly strong crude glycerines, containing, say, above 60 per cent. glycerol, and is therefore not applicable to the examination of soap lyes in their original state. I n the latter case the bichromate method seems to be the more convenient one, but here also I find that the bichromate method leads to too high results if the lyes are very impure.A correct method of testing the glycerine is, as I have stated elsewhere, to take 1,000 C.C. or 1,000 grammes, purify the lye, and concentrate down so as to prepare a crude glycerine, in which the glycerol may be estimated by the acetin method. In my own practice, based on a number of checked experiments, I rapidly heat the ether-alcoholic solution of the crude glycerine, after evaporating off on the water- bath, to 150" C., weigh, burn off the glycerine, and weigh again. The difference represents the contents of glycerol. The following table (No. 1I.j gives a number of lyes tested by both methods. I t brings out the same point which I have illustrated by the first table-namely, that agreement is only obtained in the case of pure lyes, but that the bichromate method yields too high results if the lyes are impure.THE ANALYST.107 No. TABLE 11. Comparison of the Acetin and Bichromate Methods for Determining the Percentages of Glycerol in Soap Lyes. Specific Gravity. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 1.120 1.114 1.216 1-1025 1.0975 1.1050 1.0925 1.1025 1 *09 5 1.2025 1.0925 1.09 1.085 1-22 - - Free Alkali, a.s Na,O, per Cent. 2-39 0.58 0.927 0.452 0.678 0.809 1.6 0.863 1.933 0.51 0.768 0-657 0.49 - - - Glycerol, per Cent. Bichroniate Method (Copper Sulphate). 1,000 C.C. Method. 6.62 ; 6.80 8.48; 8.43 5.89; 5.81 7.45; 7.33 5.90; 6.09 5.34 ; 5.43 5.92 ; 5-88 5.65 6.92; 6.93 9.68; 9.67 6-95; 7.07 6.78; 6.42 5.42; 5.45 4.59 7.66; 7-69 12.5 ; 12.6 5.86 7.36 5-70 6.69 5.90 5.25 6-10 5.64 6.95 9.75 6.96 6.62 5.70 11-57 3.57 7.55 The bichromate method suffers from the inherent fault that everything which is oxidizable to carbonic acid is reckoned as glycerine, whereas the acetin process accounts only for those substances which contain hydroxyl groups.The chief impurities are, of course, lower fatty acids, which in the bichromate method are oxidized. In the acetin method, impurities of a, non-alcoholic nature do not interfere with the accuracy of the results. But even if an impure crude glycerine did contain trimethyleneglycol, the acetin method would rather indicate lower results than the true one, whereas the bichromate method would yield too high a number. Chau*meil (Bull. Soc.Chim., xxvii., 629) prefers iodic acid as an oxidizing agent to bichromate, and proposes a method of determining glycerol, which is based on the reaction expressed by the equation : 5C,H,O, + 7I,O, = 15C0, + 20H20 + 71,. I have not examined this method, as it has the same inherent fault as the bichromate test-namely, that everything oxidizable counts as glycerine. It appeared, therefore, unnecessary to carry out any experiments, all the less so as Bernard (Pharm. Central-Halle, xliii., 541) has shown that the method is unreliable even in the case of distilled glycerine. Gailhat’s oxidation method, using permanganate in presence of manganese sulphate, need only be noticed in passing. Verley and Bolsing proposed (Berichte, 1901, 3354) as a general method for the quantitative estimation oi alcohols, and amongst them of glycerol, a modification of108 THE ANALYST.the acetin method, consisting in the addition of pyridine to the acetic anhydride, their contention being that the pyridine accelerates the reaction so considerably that the determination can be carried out by warming on the water-bath for a quarter of an hour without even requiring a reflux condenser. I have tested this method on crude glycerine and also on chemically pure glycerine, but the results obtained were utterly unsatisfactory. The ideal method for the determination of glycerol would, of course, be one which would enable us to isolate the glycerol either as such or in the form of a derivative; therefore the method proposed by Zeisel and Fanto (Zeit. f.d. Zand- wirthsch. Versuchswesen in Oest., 1902) naturally attracted my attention, The method is based on the reaction expressed by the folIowing equation : The glycerol is converted by means of hydriodic acid of 1-7 and even 1.9 into isopropyl iodide, and the latter distilled over into an alcoholic solution of silver nitrate. The iodine, which is formed s t the same time, is retained by red phosphorus. Silver iodide is precipitated and weighed as such, and each molecule of AgI calculated to 1 molecule of glycerol. I have made two series of experiments on crudeglycerine, but the results have been so much below the truth that I do not feel encouraged to continue my experiments. Besides, the method is so cumbersome when compared with those in vogue that there is little inducement for adopting it in the estimation of crude glycerine.Messrs. C. D. Robertshaw and G. Warburton have assisted me in the experiments enumerated above. C3H5(OH)3 + 5HI = C,H$ + 3H,O + 21,. The test is carried out in the apparatus shown on the lecture table. DISCUSSION. Mr. HEHNER said that it had long since been pointed out that, while the results of the bichromate method had a tendency to be too high, the tendency of those of the acetin process was in the reverse direction. The hydrolysis of triacetin was very readily brought about, and if, in the neutralization of the free fatty acid in the acetin process, any alkaline reaction at a11 were allowed to occur, the result would be a partial hydrolysis of the triacetin, and as a consequence the final result would be too low.Evidently, however, some change (which no doubt Dr. Lewkowitsch would be able to point out) had taken place in the actual conditions of manufacture since the time when he (Mr. Hehner) had compared the two methods and had found them to give substantially agreeing results with both soap and candle glycerines. Possibly, as a result of more rapid boiling at higher temperatures, there was now a tendency towards the formation of condensed glycerines or polyglycerines, which, while being oxidized by bichromate almost in the same way as glycerine, would certainly not be acted upon to a corresponding extent by acetic anhydride. He had investigated the question of the possible oxidation by bichromate of those lower fatty acids which were not precipitated by lead acetate or silver carbonate, and had come to the con- clusion that, with proper precautions, no such oxidation occurred.Certainly there was no oxidation in the case of butyric acid, provided there was not too much sulphuric acid present.THE ANALYST. 109 Dr. LEWKOWITSCH said that undoubtedly the acetin process was a somewhat difficult one to carry out accurately, but his own work included a great number of glycerine analyses, so that there was full opportunity in his laboratory for attention to even the smallest details, and consequently, in such a matter as the avoidance of an alkaline reaction in neutralization, the proper limit was not overstepped. The fact was that since 1897 the prices of raw materials had risen so greatly that both Roap-makers and candle-makers had been obliged to fall back upon the cheapest materials they could get.Soap-makers, especially the smaller ones, could not afford to buy high-priced tallow, oils, or fats, and had to use bone-grease, skin-grease, and like materials, containing, as a matter of course, large amounts of free fatty acids, and, what was especially important in the present case, of lower fatty acids, which were brought down into the crude glycerine. Theoretically, the lower fatty acids ought to boil away, but they did not, and were to some extent retained in the impure crude glycerine. They were then, in the course of the analysis, oxidized by bichromate, especially on heating, although the pure fatty acids might not be oxidized so readily. In candle-making, in consequence of this forced utilization of materials of low quality, acid saponification methods had to be resorted to, with the result that, starting with impure materials, the crude glycerine was likewise impure.I n all the cases in which large discrepancies were shown between the two methods, the glycerines contained large proportions of ash. In crude candle glycerine, for instance, the ash ought not to exceed about 0.5 or 0.6 per cent., whereas in these samples it amounted to nearly 2 per cent., consisting mainly of sulphate of lime or some other sulphate. Polyglycerines would, of course, not be accounted for in the acetin process ; but, as a matter of fact, polyglycerines were only to be found in distilled glycerines, or in crude glycerines which had been subjected to distillation, and not in such ordinary crude glycerines to which the present paper was confined.The tempera- ture at which such glycerines were concentrated rarely exceeded 90" C., which was insufficiently high for polymerization to take place. Mr. HEHNER suggested that the relative accuracy of the two methods might be to some extent tested by ascertaining the amount of specific gravity due to glycerine, after deducting that due to ash. If there were present a sufficient proportion of, say, caproic acid to appreciably affect the result yielded by the bichromate method, the specific gravity of the sample would be lower than that indicated by the glycerine and ash percentages. Dr. LEWKOWITSCH said that, as a matter of fact, the influence of the glycerine on the specific gravity was slight as compared with the influence exercised by the ash, and both were liable to variation. In the concentration of glycerine counter- acting influences were exercised, on the one hand, by the salt dropping out of solution, and on the other by increase in the proportion of glycerine. At every stage of the process there existed an equilibrium between the water, glycerine, and salt ; and if that equilibrium were disturbed by the dropping out of some of the salt, the specific gravity could only be raised by increasing the amount of glycerine and decreasing the amount of water.

ISSN:0003-2654    

DOI:10.1039/AN9032800104

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年代:1903

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110 THE ANALYST. ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. Estimation of Ethyl Alcohol in Essences and Medicinal Preparations. T. E. Thorpe and J. Holmes. (Proc. Chem. Soc., 1903, xix., 13.)-The following method is used in the Government Laboratory for estimating ordinary alcohol in essences and medicines containing essential oils and volatile substances, such ether, chloroform, benzaldehyde, camphor, and compound ethers. Twenty-five C.C. of the sample are placed in a separating funnel, diluted with water to 150 c.c., and the solution is saturated with sodium chloride. The mixture is then shaken for five minutes with 50 C.C. to 80 C.C. of petroleum spirit (boiling below 60" (2.). After standing thirty minutes, the lower layer is drawn off, extracted a second time with petroleum spirit, and introduced into a distillation flask.The petroleum layers are washed several times with saturated sodium chloride solution, the washings being added to the main solution in the flask. Distillation is then proceeded with, the distillate is made up to 100 c.c., and the specific gravity taken. To allow for the fourfold dilution of the original spirit a correction must be applied to the amount of alcohol found from the specific gravity of the distillate. The mean error for alcohol below 40 per cent. proof is +0.2, so that 0.8 per cent. must be subtracted from the percentage of proof spirit found. Details of the method of determining this error for other strengths are given, as are also the results of analyses of prepara- tions containing known quantities of ethyl alcohol.w. P. s. On the Composition of Cows' Milk. H. C. Sherman. (Joarrt. Amer. Chem. SOC., xxv., 132.)-From his monthly analyses, extending over a period of two years, of the milk from one herd of cattle, the author shows that the percentage of protein, like that of fat, varies with the season, being higher in autumn and spring than in w i n k and summer. The percentage of milk-sugar remains nearly constant through- out the year. A milk rich in fat is also generally rich in protein, the excess of protein above the normal averaging about one-third the excess of the fat. The author agrees with Richmond's conclusion (ANALYST, xxv., 225) that any deficiency of solids-not-fat is due chiefly to a deficiency in the milk-sugar, any excess above 9 per cent.being due chiefly to an excess of protein. The relation found by Richmond (ANALYST, xxvi., 310) between the ash and protein-namely, ash = 0.36 + 0.11 protein-applies very nearly to the author's results, which correspond, however, a little more closely to the formula, ash = 0.38 + 0.10 protein. A. G. L. Detection of Sesame Oil in Butter obtained from Cows fed on Sesame Cakes. A . J. Swaving. (Zeit. fiir Untersuuch. der Nalar. und Genussmittel, 1903, vi., 107-115.)--As the result of a number of feeding experiments with sesame cakes,THE ANALYST. 111 the author states that the constituent of sesame oil which gives the coloration in Baudouin’s and Soltsien’s reaotions, is not to be found in the butter-fat of the COWS so fed.In no case could a coloration be obtained. w. P. s. A Method for Comparing the Aroma of Coffee. Lebbin. (Zed. far 6feiztl. Chem., 1902, viii., 455-461.)-0ur knowledge of the constituents of coffee has hitherto been limited to data which, though they well serve to define its chemical constitution, and are useful in detecting its adulteration, afford no clear indication as to its pecuniary value. The value of a coffee is determined by the consumer almost exclusively from its richness or poverty in aroma, less notice being taken of other constituents, such as tannin, bitter principle, etc. The author has endeavoured to find out a satisfactory method of chemically determining the amount of this aroma, which is as follows : One hundred grammes of ground roasted coffee are mixed with 400 C.C. of water in a flask, and distilled over an oil-bath.300 C.C. of distillate are collected, the heat being so regulated that this quantity comes over in from one to one and a half hours. After mixing, one-half of the distillate is treated with succinic acid to remove pyridine. 50 C.C. of the rectified solution are then mixed with 50 C.C. of 7 per cent. iodic acid solution, and allowed to stand for ten minutes. The liberated iodine is Bhaken out with three successive quantities of chloroform, and titrated with i& sodium thiosul- phate solution. The number of C.C. of the latter used multiplied by six gives the quantity corresponding to the 100 grammes of coffee taken, and this the author terms the aroma value. On keeping in glass vessels, the value gradually decreases to about one-third at the end of eighty days.Kept for the same time in paper bags, the aroma diminishes to about one-eighth of the original value. When coated with sugar or shellac, very little loss of aroma takes place. The author states that the reduction of iodic acid is proportional to the amount of aroma in the coffee. It is necessary to shake out the liberated iodine with chloro- form before titrating, as a small quantity of iodine in the presence of much iodic acid gives no blue colour with starch solution. The author is at present engaged in ascer- taining the chemical composition of the constituent or constituents from which coffee derives its aroma. w. P. s. Freshly roasted coffee has a value from 75 to 105. A New Cinnamon Adulterant.W. Schmitz. (Zeit. fiir ofentl. Chem., 1903, ix., 32-33.)-The author has recently met with two samples of ground cinnamon adulterated with powdered galangal root (Rhizoma gakange). A microscopic examina- tion showed the presence of yellowish-brown splintered fragments, similar to powdered shellac. These particles were not attacked by alkalies or acids and were insoluble in alcohol, ether, and chloroform. As no yellow oil-cells could be observed, the galangal root had probably been previously extracted. w. P. s. Ferric chloride turned the fragments black. The Action of Certain Artificial Colours of the Aromatic Series on the Digestive Process. ( R z m k i Wratsch, 1902 [50] ; Biochem. Centralblatt, 1903, i., 232.)-The author has studied the influence of twenty-five A.I. Winogradow.112 THE ANALYST. different colouring matters upon the artificial peptic digestion of egg-albumin, and has found that the following twelve added in the proportion of 0.01 to 0-1 per cent. have a strong restrictive effect : Saffron, Ponceau R.R., azofuchsin, orange II., caerulein S, phloxin R. B. N., iodeoain, chrysaniline, Magdala red, azoflavin, benzo-purpurin, and cerise. The following also interfered with the digestive process, though to a much smaller extent than the others : Chinolin yellow, methylene green, acid green, iodine green, azo-acid yellow C, yellow T, naphthol yellow, aniline green, primulin, aurarnin 0, aniline orange, Martius' yellow, and metaniline yellow. C. A. M. A Reaction of Pyramidon. G. Rodillon.(Joum. P1zal.m. Chim., 1903, xvii., 172, 173.)-Pyramidon (dimethyl-amido-dimethyl-oxyquinizine) in aqueous solution has the property of giving a blue coloration with gum arabic in contact with the air at a temperature not exceeding 85" C. This reaction, which Deniges attributes to the action of an oxydase, can also be produced by the restricted action of an oxidizing agent, such as hydrogen peroxide, alkaline hypochlorites, manganese dioxide, etc. Thus, if 0.1 gramme of pyramidon be dissolved in 5 C.C. of water, and the solution treated with 1 drop of a solution of a hypochlorite, an immediate blue coloration is obtained; or the hypochlorite can be replaced by a few drops of hydrogen peroxide, but it is then necessary to heat the liquid to 60"-70" C. This reaction can be used as the basis of a colorimetric quantitative method. With ferric chloride, pyramidon gives an intense violet coloration similar to that given by phenols.C. A. M. The Reactions of Guaiacol. G. Guerin. (Jounz. Phann. Chim., 1903, xvii., 173, 174.)-Alcoholic solutions of guaiacol, treated with 1 drop of alcoholic ferric chloride solution, give a bright blue coloration, changing to green on the addition of more of the reagent. Aqueous solutions under the same conditions give brown colorations and become turbid. On adding ammonia and then an alkaline hypo- chlorite to an aqueous solution of guaiacol, and applying heat, a green coloration is obtained. An aqueous solution of guaiacol, treated with a few drops of a 10 per cent. solution of sodium nitrite, and then with 1 drop of nitric or sulphuric acid, yields a reddish-orange colour.With chromic acid solution (1 to 2 per cent.) aqueous solutions of guaiacol give brown colorations and precipitates; whilst with iodic acid solutions of the same strength they yield orange-brown colorations and orange precipitates. C. A. M. The Identification of Ordinary Tartaric Acid by Means of Lsevo-Tart aric Acid. (Zeit. anal. Cherm., 1903, xhi., 15-19.)--The following test , based on the insolubility of calcium racemate, is stated to be sensitive and applicable in all caseB. If a 1 per cent. aqueous solution of tartaric acid be treated with a slight excess of calcium acetate, crystals of calcium tartrate, CaC4H,0,.4H,0, are deposited after a few minutes. On now adding to the clear supernatant solution, J.N. Bronsted.THE ANALYST. 113 containing about 0.1 per cent. of tartaric acid, a few drops of a solution of l ~ v o - tartaric acid, a white precipitate of calcium racemate, CaC4H406.6H,0, is speedily formed. In solutions of greater concentration (0.6 per cent.) the reaction is less characteristic, whilst when the amount of tartaric acid is less than 0.1 per cent. longer standing is required for the precipitate to be formed. Tartaric acid can be detected in this way, even in the presence of a large excess of other substances giving precipitates with calcium acetate (e.g., oxalic and citric acids). Thus, the author identified tartaric acid in a 0.001 per cent. solution containing 0.5 per cent. of citric acid. In all cases the racemate crystals should be identified, under the micro- scope, if necessary after solution in dilute hydrochloric acid and reprecipitation by sodium acetate or calcium acetate.Racemic acid can be rapidly and accurately determined by precipitation from an acetic acid solution by means of calcium acetate; and, conversely, calcium can be determined by precipitation in the cold with ammonium racemate. Thus a solution of calcium chloride analysed by the usual method was found to contain 1-693 per cent. of calcium, whilst by the racemate method it yielded (1) 1.693 per cent. and (2) 1.692 per cent, of calcium. C. A. M. A Reaction of Cacodylic Acid and Cacodylates. J. Bougault. (Jozwn Pharm. Chim., 1903, xvii., 97, 98.)-A solution of hypophosphorous acid in hydro- chloric acid (strength not given) is a characteristic reagent for the identification of cacodylic acid and its salts, and for their detection in other arsenical compounds, particularly disodium methyl arsenate. A solution of 0.2 gramme of the latter salt in I to 2 C.C. of water is mixed with 10 C.C. of the reagent, and the tube closed and left for twelve hours. A strong cacodylic odour is then perceptible if the methyl arsenate contains as much as 0-5 milligramme of cacodylate. For the detection of other arsenical compounds in cacodylates 0.2 gramme of the salt is dissolved in 1 to 2 C.C. of water and mixed with 10 C.C. of the reagent. In the case of pure cacodylate no coloration or deposit of arsenic is produced in the liquid, whilst a trace of arsenic (less than 0.1 milligramme of arsenious or arsenic acid) causes a brown coloration or precipitate. Only by using very strong solutions of cacodylate is it possible to obtain a slow deposition of arsenic with this reagent. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9032800110

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年代:1903

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THE ANALYST. 113 TOXICOLOGICAL ANALYSIS. (Oestew. Chem. Zeit., 1902, v., 559.)-The author has reinvestigated the processes described by Rossel (ANALYST, 1902, xxvii., 367) and by Vitali (ibid., p. 329) for the recognition of blood-stains or blood in urine. Vitali's process works perfectly, and the presence of blood on iron, in the presence or absence of rust, or on dried fabrics, can be ascertained with it. As a solvent for the spots, the usual physiological solution of common salt may be employed. It is a matter of complete indifference whether the guaiacum tincture is that of the resin or of the wood; and in contradistinction to the test for heated milk fresh tinctures Detection of Blood. Utz.114 THE ANALYST. work as well as old ones; very old specimens, however, were not investigated.Nevertheless, Utz considers it advisable to carry out a confirmative test, either on 8, sample known to contain blood or by means of Rossel’s reaction. I n the Rossel test, after the ether has been shaken with the reagent and the liquid has settled, the aqueous layer is at first orange, but gradually changes to red. Utz has never found a cherry red to appear in ten minutes ; it requires much longer to develop-sometimes an hour if the proportion of blood present is small. It may, however, be hastened by allowing the mixture to rest quietly for fifteen or twenty minutes and then shaking it briskly. Generally the aqueous layer then appears pale carmine red, the ether having a faint wine-yellow colour. Vitali’s test is the more delicate, rapid, and distinct of the two; but Rossel’s reaction is specially suitable for corroborative evidence, particularly when there is not sufficient of the sample to examine in the spectroscope, when the formation of Teichmann’s haemin crystals is impossible, or when there is no serum to investigate.F. H. L. Notes on the Reactions of Blood with Guaiacum and Aloin. E. Schaer. (Zezt. a n d Chem., 1903, xlii., ‘i-lO.)-The blue coloration produced by the action of hydrogen peroxide or ozonized ” turpentine oil upon guaiaconic acid in the presence of an oxygen-carrying substance in the colouring matter of the blood has frequently been condemned as a test for blood-stains, on the ground that many other substances, e.g., enzymes and oxidizing metallic salts, produce the same results. In the author’s opinion, however, it is reliable if proper precautions be taken. Under analogous conditions aloin (barbaloin and natalaloin) forms a red com- pound, aloin red, which will afford confirmatory evidence, though control experiments must also be made in this case. The test is applied by extracting the blood-stains (even when very old) with a concentrated (70 to 75 per cent.) solution of chloral hydrate, mixing the extract with a weak solution of aloin and chloral hydrate, and pouring on to the surface of the liquid either <‘ ozonixed ” turpentine oil, or, for a more rapid reaction, hydrogen peroxide solution. In a short time a violet-red zone is formed, which gradually changes into a red coloration of the aloin solution. (Cf. ANALYST, xxiv., 266.) C. A. M.

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DOI:10.1039/AN9032800113

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年代:1903

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摘要:

114 THE ANALYST. ORGANIC ANALYSIS. Notes on the Biuret Reaction and the Cupric Reducing Power of Sugars. E. Schaar. The Biuret Reaction .-The characteristic bluish- or reddish-violeb colour given by biuret and certain proteids in the biuret reaction can also be produced by replacing caustic alkalies by other alkaline substances, such as barium and calcium hydroxides, alkali carbonates, ammonia, trimethylamine, coniine, piperidine, and atropine. The reaction takes place with nearly insoluble alkaline substances like magnesium oxide on heating as readily as in the ordinary method of applying the test,. (Zed. anal. Chem., 1903, xlii., 1-6.) Copper sulphate can also be replaced by any other soluble copper salt.TEE ANALYST. 115 The Reduction of Cupric Salts in Alkaline Solution by Szcgar.--This rea,ction presents many analogies with the biuret reaction.Thus, speaking generally, it may be asserted that the conditions under which a copper salt and alkaline substance give the biuret reaction with a proteid are the same as those under which reduction takes place with Fehling’s reagent. In this test the potassium or sodium hydroxide can also be replaced by barium or calcium hydroxide, or even by theonly slightly soluble magnesium oxide. Ammonia, too, which is used in addition to fixed alkali in certain sugar reagents, is also capable of effecting by itself energetic oxidation of glucose. I n Trommer’s reagent for sugar determination caustic alkali can be replaced by certain salts with alkaline reaction, such as potassium and sodium carbonates and borax, in which we may assume that dissociation and formation of sodium hydroxide takes place.On the other hand, other salts that undergo partial dissociation-e.g., sodium salicylate, sodium phosphate, sodium nitrite, .and aluminium acetate-are without action. The reduction of a solution of copper sulphate and lead acetate is to be attributed to the formation of copper acetate (Barfoed’s reagent), which has the same action on sugars as an alkaline copper solution. As regards the action.of organic alkaline substances, the author found that coniine, nicotine, piperidine, and triethylamine effected the reduction, whilst other bases, such as atropine and codeine, had little, if any, action, as was also the case with aniline, acetanilide, antipyrin, glycocoll, and urea, and with the non-basic substances, hydrocyanic acid and other cyanogen compounds, haloid salts, hydrogen peroxide, and colloidal platinum.As in the case of the biuret reaction, any soluble copper salt may be used in place of copper sulphate in the sugar reaction, and in the case of organic copper salts with weak basic alkaline substances the reduction is more rapid and complete than when copper sulphate is employed. The author points out that it may be possible to detect the presence of small quantities of basic substances in pathological urine by the simple addition of glucose and a solution of a neutral copper Ralt. C. A. M. Estimai?ion of Stearic Acid. 18. Kreis and A. Hafner. (&?it. fur UrtteYSUCh. der Nalar. und Genussmittel, 1902, vi., 22-27.)--From an investigation of the method of estimating stearic acid described by Hehner and Mitchell (ANALYST, 1896, xxi., 316-332) the following results were found : Palmitic acid is not as soluble in alcohol (94.4 per cent.by volume) as stated by Hehner and Mitchell, stearic acid being also slightly less soluble. The authors, however, employed pure ethyl alcohol, whilst in the method as originally given rectified alcohol obtained from methylated spirit was used. The solubility of stearic acid is not affected by the presence of palmitic and oleic acids. Provided that the alcohol be saturated with stearic acid at 0’ C., the strength of the alcohol was not found to be of importance, but spirit containing less than 94 per cent. of alcohol dissolves very little pelmitic acid.When only small amounts of stearic acid are present, supersaturation may take place and no yield be obtained. Not less than 0.5 gramme of the mixed fatty acids should be employed in an estimation. The author considers that the method may be useful for detecting116 T E E ANALYST. margarine in butter. Butter-fat was not found to be free from stearic acid, but the quantity of the letter was too small to be estimated. w. P. s. Detection of Rosin in Naphthalene. R, Hodurek. (Oesterr. Chem. Zeit., 1902, v., 555.)-The Storch-Morawski reaction does not serve to indicate the existence of small quantities of colophony in naphthalene. If, however, naph- thalene which does not contain too much rosin is melted and raised to such a temperature that it does.not solidify during the test, and a little strong sulphuric acid is run down the side of the tube containing it, a fine cornflower-blue colour appears at the junction of the liquids, which on gentle agitation passes to the naphthalene, but does not tint the acid. Larger proportions of rosin (which are not likely to be met with) yield reddish-brown colours, but the blue may be obtained by diluting the sample with pur; naphthalene.Crude naphthalene is not so amenable to the test, but with practice the reddish-violet colours may be recognised. I t is interesting to notice that this is a Storch-Morawski reaction obtained in the absence of chloroform and acetic anhydride. If colophony is dissolved in petroleum spirit, chloroform, ether, alcohol, etc. , and treated with sulphuric acid, no colour develops unless acetic anhydride is added ; in fact, the use of chloroform is unnecessary, and, indeed, harmful.The proper solvent for the body supposed to contain rosin is acetic acid or anhydride. By the same test rosin can be detected in toluene, and the higher coal-tar hydrocarbons, in presence of acetic or other organic acids, or of acetic anhydride. A sufficiently high temperature, however, is necessary ; for if naphthalene, just at its melting-point, is treated with sulphuric acid warmed to 80" C. no colour appears until the mixture is heated further. On adding a few drops of alcohol the blue naphthalene layer is bleached, and the acid becomes bright red. Ether, acetone, glycerol, formaldehyde, and large quantities of chloroform act similarly, hence, for this reason the presence of the chloroform in the Storch-Morawski test is said to be objectionable. F.H. L. The Quantitative Determination of Tannic Acid by Means of Ferric Salts. Ruoss. (Zeit. anal. Chem., 1902, xli., 717-'734.)-Handtke's method of precipitating tannin with iron (Zeit. anal. Chem., i., 104; iii., 126) suffers from the drawback that iron acetate yields precipitates in which the percentage of iron ranges from 17 to 39 per cent., that the precipitation is very tedious and incomplete, and that gallic acid is also precipitated. In the author's method the tannic acid is first converted into sodium tannate, and the solution treated with ferric sulphate, which precipitates a basic tannate, from which the excess of ferric hydroxide can be removed by treat- ment with dilute acetic acid (or can be prevented from forming), leaving a hitherto undescribed insoluble tannate, which, when dried at 100' to 120" C., has the com- position (C,,H,O,)Fe.The precipitate, in the author's opinion, is a basic tannate in which the hydrogen of the tannin carboxyl group is replaced by the monovalent group [FeO]. Thus : C,,H,O,(FeO) = (C,,H,O,)Fe + H,O.THE ANALYST. 117 The-solutions required for the determination are (1) 4 sodium carbonate solution, 71.3625 grammes per litre. strength- e.g., 50 grammes of ferric sulphate, or a corresponding quantity of ferric ammonium sulphate or ferric chloride in a litre. The liquid must not be boiled, and must be kept protected from light. (3) A solution of 5 grammes of sodium tartrate in a litre of 6 per cent.acetic acid. It is essential that the ferric sulphate solution should be at least equivalent to the sodium carbonate solution-i.e., when 10 C.C. of the two solutions are boiled together and filtered, the filtrate must not give an alkaline reaction with methyl orange. A further test of the suitability of the solutions is that on mixing 50 C.C. of water with 10 C.C. of the sodium carbonate solution and 10 C.C. of the iron solution, and immediately adding 25 C.C. of the sodium tartrate solution, the liquid must remain perfectly clear after being vigorously boiled for five minutes. The tannin solution may be neutral or faintly acid or alkaline, but must be of such a strength that the residue of ferric oxide eventually obtained does not exceed 50 milligrammes --i.e., must not contain more than 0.4 per cent.of tannin. In the determination, 50 C.C. of a tannin solution of the above approximate strength are shaken with 10 C.C. of the sodium carbonate solution and 10 C.C. of the iron solution (liberation of carbon dioxide), and then immediately mixed with 25 C.C. of the sodium tartrate solution, and well shaken. I t is then boiled vigorously for a minute and filtered, and the filter washed with hot water until the washings are free from iron. The precipitate is then dried, ignited, and weighed, and its weight, multiplied by the factor, (2) Solution of a ferric salt of not less that 321.22 0.7001 - 4.024, ~ _ _ _ ~ - 56 gives the amount of tannic acid (molecular weight = 321.22) in 50 C.C.of the tannin solution. The author gives the results of experiments showing that the precipitation of tannin is complete, and that only gallic acid, which gives a brown coloration, but no precipitate with the reagents, passes into the filtrate. The ordinary method of determining tannin by absorption with hide powder is shown by the author to have the drawback that a large amount of colouring matter is simultaneously absorbed. Reagents for Tannic and Gallic Acids.-The author asserts that the generally accepted statement that tannic acid gives black precipitates with ferric salts, and that it gives no coloration with ferrous salts, is incorrect. He finds that ferric acetate gives a black precipitate with tannic acid, and a black precipitate or coloration with gallic acid, according to the degree of concentration; and also that tannic acid gives a black precipitate with ferrous acetate.Moreover, on adding a solution of ferric salt, drop by drop, to a solution of tannic acid, no precipitate is obtained, but only a dark colour, since the iron tannate is readily soluble in excess of tannic acid. Gallic acid also behaves in the same way, so that a dark coloration with ferric salts is inconclusive. The following two reagents, however, have been found accurate and extremely sensitive. Reagent 1.-(I) Solution of 20 grammes of ferric sulphate per litre ; (2) solution of 28 grammes of crystalline sodium carbonate per litre; (3) acetic acid (specific118 THE ANALYST. gravity 1.04) containing 5 grsmmes of sodium tartrate per litre.The tannic acid solution is first diluted to such an extent that, on adding the iron solution drop by drop, the liquid is finally still slightly transparent. About 10 C.C. of such B solution are now mixed with the iron solution, added drop by drop until the colour no longer becomes perceptibly darker. The same number of drops of solution (2) are now added, and twice the quantity of solution (3). After being shaken and allowed to stand, a black precipitate is deposited, whilst in the case of gallic acid there is no precipitate. Reagent .II.-(l) Solution of 10 grammes of ferric sulphate + 15 grammes of sodium acetate + 1.7 gramme of sodium tartrate per litre ; (2) gelatin solution prepared by dissolving 1.25 grammes of gelatin in 125 C.C. of hot water, and adding 875 C.C.of acetic acid of specific gravity 1.064 (glacial acid). Ten C.C. of the tannin solu- tion are treated with solution (I), added drop by drop until the colour ceases to darken, and then with the same quantity of solution (2). After being shaken and left for some time, the liquid yields a flocculent blue-black precipitate containing the tannic acid. Oxidation Reaction.-When 10 C.C. of the diluted slightly acid or neutral tannin solution are shaken with one drop of the solution (1) of Reagent I., tannic acid gives a permanent dark coloration, whilst gallic acid gives a black colour, immediately changing to yellow, If ferric acetate be used instead of ferric sulphate, the dark coloration is also permanent in the case of gallic acid. Griessmayer’s reaction for tannic acid (Classen’s “ Handbuch der Qual.Anal. ,” fifth edition, p. 163) is inconclusive, since it is also given by gallic acid. The reaction is capable of detecting 0.001 per cent. of tannic acid. C. A. M. The Composition of 1ndiarubber.-At a, recent meeting of the North-Eastern Section of the American Chemical Society, at Boston, Mass., Dr. C. 0. Weber, of Manchester, England, gave an account of researches on rubber. Indiarubber, no matter from what source, is, when freed from albuminous and resinous materials, composed of two bodies : one, amounting to not more than 4 per cent., is insoluble in all solvents so far tried, and corresponds to the formula CSOH68010; the other is a, hydrocarbon C,,H,,. On dry distillation, this body gives isoprene, inactive limonene, and hevehe.Isoprene, on standing, polymerizes into rubber. Nitro-compounds have been obtained in quantitative proportion from rubber. They are, empirically, C,,H,,N,O, and CloH,,N,O, respectively, and may ultimately elucidate its composition. Rubber is probably a polymerized, unsaturated hydrocarbon with an open chain and three double bonds for CloHl,. Kondadoff has obtained synthetically a compound that seems to be a methyl derivative of rubber. Vulcanization is tho direct addition of sulphur when pure rubber is used. The proportion of sulphur ranges from that required by the formula Cl,oH,,,S,, to that required for C,,,H,,S. H. L. The Differentiation of Human and Animal Bones. A. Schutze. (Biochem. Centralblatt., 1903, i., 248.)-The Berum diagnosis method of distinguishing between the blood of different animals (ANALYST, xxvii., 250) can also be used for theTHE ANALYST.119 differentiation of the bones. For this purpose fragments of bone containing marrow substance were extracted with a 0-85 per cent. solution of sodium chloride and 5 C.C. of the clear filtered extract treated with 0-5 and 1 C.C. of the respective specific sera. I n this way the bones of the different species of animals could be readily identified, even when they had been kept at the ordinary temperature for three weeks. I t was not possible, however, to distinguish between bones only containing the compact tissue, which consists mainly of inorganic salts with but little proteid matter, nor could bones containing medullary substance be recognised after being heated for an hour in a steam kettle.C. A. M. Estimation of Chlorine in Urine, Sputum, Serum, and Defibrinafed Blood by the Magnesia Process. C. Strzyzowski. (Oesterr. Chem. Zeit., 1903, vi., 27.)- Five reagents are required: (1) Mqpesium oxide, free from chlorine if possible; (2) sulphuric acid, diluted till 10 C.C. dissolve 1 gramme of MgO; (3) precipitated calcium carbonate free from chlorine; (4) 10 per cent. solution of potassium chromate; and (5) silver nitrate, containing 29.075 grammes per litre, of which 1 C.C. is equivalent to 0.01 gramme of NaCl, or to 0.00606 gramme of C1. Having first ascertained the amount of chlorine in the magnesia, 1 gramme of the latter is placed in a small platinum crucible, and 10 C.C.of the sample, if liquid (5 to 10 grammes of a sputum), are added. The whole is dried down on the water-bath or over a small flame, and then ignited in the covered crucible to a moderate red heat. Before removing the lid to see if incineration is complete the burner should be taken away for fifteen or thirty seconds. The process takes about fifteen minutes or half an hour in the presence of much sugar or albumin, but may be accelerated by stirring the contents with a flat glass rod. The mass is then mixed with 5 C.C. of water, 10 C.C. of the prepared sulphuric acid being next added, and stirred till the magnesia has dissolved. The liquid is transferred to a beaker, the deposit rinsed off the lid, any carbonaceous residue, due to imperfect combustion or to the presence of blood, being removed by filtration.The excess of acid is neutralized by means of the calcium carbonate, 5 drops of the chromate solution are introduced, and the liquid is titrated with the silver oolution in the usual way. F. H. L. The Quantitative Separation of Leucine and Tyrosine. S. Habermann and R. Ehrenfeld. (Biochem. Centralblatt., 1903, i., 87.)-The method is based upon the difference of solubility of these substances in glacial acetic acid, 100 parts of which dissolve 10.90 parts of leucine and 0.145 part of tyrosine at 16' C. Even at the boiling temperature of the glacial acid the solubility of tyrosine is only slightly increased, 100 parts then dissolving 0.18 part. When crude mixtures of leucine and tyrosine, as obtained in the hydrolysis of casein by means of hydrochloric acid in the presence of stannous chloride, are boiled under a raflux condenser with glacial acetic acid, the leucine readily passes into solution, whilst the tyrosine remains undissolved, and can be filtered off, By the addition of an equal volume of alcohol (96 per cent.) to the acetic acid the tyrosine is randered quite insoluble, and in a series of test experiments120 THE ANALYST.with mixtures of known quantities the author recovered the theoretical amounts of leucine from their solution in this solvent. C. A. M. Liquid Baths for Melting-point Determinations. Heyward Scudder. (Jozmz. Amer. Chem. SOC., xxv., 161.)-For temperatures up to 3 2 5 O C. the author recom- mends the use of a mixture prepared by boiling together for five minutes 7 parts by weight of sulphuric acid (specific gravity 1.84) and 3 parts of potassium sulphate. This mixture does not solidify at ordinary temperatures. If 6 parts of acid and 4 of the sulphate are used, the resulting mixture boils above 365" C., and solidifies between 60" and 100" C. Both these mixtures are colourless, and give off so little vapour that rubber bands may be used to fasten the capillary to the thermometer. They may be freed from any organic matter by adding a little potassium nitrate, It also ?nay be freed from organic impurities by means of potassium nitrate, but must always be poured out of the beaker on to a tile after use, as it expands on cooling. For temperatures from 360" to 600" C. zinc chloride should be used. A. G. L.

ISSN:0003-2654    

DOI:10.1039/AN9032800114

出版商:RSC    

年代:1903

数据来源: RSC

摘要:

120 THE ANALYST. INORGANIC ANALYSIS. The Gravimetric Determination of Mercury, and its Separation from Arsenic, Antimony, and Copper. Charles J. Pretzfeld. (Journ. Amer. Chem. SOC., xxv., 198.)-The author shows that the method of weighing mercury as siilphide gives high results, whilst the various methods depending on the reduction to mercurous chloride and weighing of this precipitate give somewhat low results when the chloride is precipitated from mercuric chloride solutions, though they give good results when the metal is present as nitrate and the reducing agent added before the sodium chloride. Precipitation with sodium arsenate, and weighing the Hg,(AsO,), obtained after drying at 100" C., also gives good results when applied to solutions free from hydrochloric acid, but is inapplicable to these.Both the electrolytic method, due to E. F. Smith, and that in which a solution of the double sulphides of mercury and potassium is used, give good concordant results. For the separation of mercury from antimony, arsenic, and copper, the author recommends the following method, which is more satisfactory than the ammonium sulphide method, and yields good results: To the clear solution of the metals a considerable amount of tartaric acid solution is added ; after stirring for one or two minutes, potassium cyanide is added gradually till a considerable excess is present, after which hydrogen sulphide is led into the solution till saturated, the liquid beiug kept cold. The precipitated mercuric sulphide is filtered off, dissolved, and the solution electroly sed.A. G. L. Rapid Determination of Molybdenum in Steel. G. Anchy. (Jown. Amsr. Chem. SOC., xxv., 215.)-In using the method previously described (THE ANALYST, xxvii., 205) the author now recommends taking only 0.8 gramme of the steel drillings,THE ANALYST. 121 making the caustic soda precipitation in a volume of 200 c.c., and taking only 100 C.C. of the filtrate for reduction and titration, whereby much time is saved. An improve- ment in the method due to Brakes (Journ. SOC. Chem. Ind., xxi., 832) is to expel the nitric acid from the original solution by evaporating to fuming with 3 C.C. sulphuric acid, as it is essential that the nitric acid should be completely expelled. A. G. L. A Chemical Method for determining the Quality of Limestones.Alfred M. Peter. (Journ. Amer. Chem. SOC., xxv., 143.)--Certain limestones containing ‘‘ blue ” layers are less valuable for exposed construction than ( ( gray ” limestones, on account of their more rapid disintegration on exposure to air. According to t h e author’s observations, the blue material may be shaly and moderately phosphatic, or very phosphatic and not especially clayey ; but it invariably contains easily soluble ferrous compounds, and a small, but very notable, amount of organic matter, which makes its presence known when the material is dissolved in dilute acids by the odour of petroleum imparted to the escaping gas, and by the brown scum floating upon the liquid. The author attributes the colour largely to the presence of ferrous phosphate, and is of opinion that the rapid weathering of ‘‘ blue ” limestone is due to the presence of easily oxidizable substances, such as ferrous compounds and organic matter, the oxidation of which is favoured by the greater porosity of this as compared with “ gray ” limestone.The porosity increases with the quantity of phosphates, and is possibly dependent upon the presence of minute shells, which sometimes give the rock a structure somewhat resembling that of chalk. Such limestone also sometimes. contains finely granular pyrites, which on oxidation assists disintegration. The author suggests that a good index of the relative stability of different limestones may be obtained by measuring the relative amounts of easily oxidizable organic matters, phosphoric acid, and clay or insoluble matters. He dissolves the limestone in dilute sulphuric acid in an Erlenmeyer flask in the presence of a known quantity of potassium permanganate, and by subsequent titration determines the quantity of permanganate consumed in the process of oxidation during half an hour at 100” C.He operates upon 1 gramme of the finely-powdered dried sample with 25 C.C. of decinormal per- manganate, and 100 C.C. of a 10 per cent. solution of sulphuric acid. More perman- ganate is added, if necessary, to maintain an excess. A blank of permanganate and sulphuric acid should be run under the same conditions. The solution obtained is filtered from the residue, which is ignited and weighed as total insoluble residue (clay and sand), phosphorus being estimated volumetrically in the filtrate.In the insoluble residue obtained from a duplicate determination the sand is deter- mined by digestion of the (unignited) residue first with sulphuric acid, and then with sodium carbonate solution, followed by ignition of the residue, the difference between this and the total residue being taken as clay. The conclusion arrived at is that limestone which consumes from permanganate much more than 0.3 per cent. of oxygen, and at the same time contains as much as 1 per cent. of phosphoric acid (more especially if it contains much “clay”), will disintegrate rapidly on exposure to air and moisture, and will be undesirable for road- building or other exposed construction.122 THE ANALYST. Average.. . ... ... 1.129 1 3.70 Highest . . .... ... 2.120 ’ 9-10 Lowest ... ... ... 0.666 ~ 0.96 Results are given of the examination of nine good and nine bad limestonee, of which results the following is a summary : 10-92 17.43 4.20 1.91 I P,Op I --- I I per Cent. Per Cent. 1 Per Cent. Tough, hard, compact stone, I resisting weathering, mostly I I gray ” : Average . . . ... ... 0.165 1 0.48 1 1.75 Highest.. . ... ... 0.341 1 1.01 2.26 Lowest ... ... ... 0.048 I 0.16 1.34 I -- I 1 Soft, porous, or shaly stone, weathering rapidly, mostly (‘ blue ”: I “ Clay. ” Per Cent. 0.52 0.66 0.13 7.05 10.23 _. - Total Insoluble. Per Ceut. -- 2-04 4.15 0-88 12.73 25.66 2.06 I A. G. L. __ Estimation of Free Lime in Thomas Meals. M. Bischoff. (Chem. Zeit., 1903, xxvii., 33.)-TT7hen a particular sample of Thomas meal was treated by the Scheibler process, agitating it with a 10 per cent.solution of sugar, the amount of lime recovered from the liquid was 6.12 per cent. after two hours’ shaking and 7.50 per cent. after twenty-four hours’ shaking. When, however, plain water was used, employing 1 litre per 1 or 2.5 grammes of meal, the yields were 2.46 and 3.10 per cent. respectively. On boiling the sugar solution, a precipitate was obtained, which proved to be calcium carbonate, and was equivalent to 3-20 per cent. of CaO. I t is therefore evident that a sugar compound with calcium bicarbonate passes into solution along with the ‘‘ saccharate ” of calcium oxide. From this it follows that when Thomas meals have to be examined for the lime content, water only should be used as the extracting liquid.F. H. L. Estimation of Citrate-soluble Phosphoric Acid. M. Passon. (Chenb. Zeit., 1903, xxvii., 33.) -The additions which Kellner and Bottcher have recently stated to be necessary (this vol., p. SO), when phosphoric acid is being determined by the direct magnesia process in Thomas meal (basic slag) liable to contain silica, seem to make the method so complicated that the oxidation process described by Mach and Passon in 1896 would appear to be simpler. This process has been somewhat modified, and iiow atands as follows : 100 C.C. of the Wagner extract are brought into a Kjeldahl flask and treated with 20 C.C. of strong nitric acid, 10 to 15 C.C. ol strong sulphuric acid, and a drop of mercury. The whole is boiled, and before it is cold a pinch of sodium chloride is added, which throws down most of the mercury. The liquid is diluted to 200 c.c., and 100 C.C.of the filtrate (=0*5 gramme of meal) are mixed with 50 C.C. of &he usual ammonium citrate solution and 20 C.C. of strong ammonia. When cold theTHE ANALYST. 123 phosphoric acid is precipitated with 25 C.C. of magnesia mixture, the whole is agitated for 5 minutes, and then filtered through a Gooch crucible. The concentrated acids separate out all the silica, whatever its proportion may be; and the method has an additional advantage in requiring only five minutes’ agitation instead of the thirty minutes’ stipulated for by Bottcher. F. H. L. Estimation of Citric Acid-Soluble Phosphoric Acid in Presence of Silica. Wm. Naumann. (Chenz. Zeit., 1903, xxvii., 121.)-Five grammes of Thomas meal are agitated in a 4-litre flask with 2 per cent.citric acid solution for thirty minutes, and 100 C.C. of the filtered liquid ( = 1 gramme of substance) are collected in a 250 C.C. flask. About 8 C.C. (one-third of the quantity formerly used in the Naumann process) of nitric acid are added to prevent deposition of calcium citrate and to promote smooth boiling, and the mixture is concentrated over a small flame till the volume is reduced to about 25 C.C. and the liquid begins to boil badly. The flask is taken from the flame, allowed to cool slightly, and either 25 C.C. of strong sulphuric acid alone, or 25 C.C. of sulphuric acid and 5 C.C. of strong nitric acid are introduced. The flask is replaced over the flame and boiled for about ten minutes till the appearance of white vapours shows that the temperature has reached the boiling-point of sulphuric acid, and that the silica is thrown out.The liquid is cooled, cautiously diluted to 250 c.c., and 125 C.C. of the filtrate (= 0.5 gramme of meal) are treated with about 35 C.C. of strong ammonia, using rosolic acid as indicator, cooled, and agitated for half an hour with 50 C.C. of 24 per cent. ammonium citrate and 25 C.C. of magnesia mixture, filtering either immediately or when convenient. By adding the nitric acid in two portions as above described no oxidation of the citric acid occurs before the concentration of the solution. The process yields pure precipitates, which filter well. F. H. L. Separation of Quartz from Amorphous Silica. B.Sjollema. ( J . L U d W . , 1902, l., 371 ; through Chem. Zeit. Rep,, 1903, 2l.)-Quartz cannot be quantitatively separated from amorphous silica either by means of sodium hydroxide or by sodium carbonate solution. The former dissolves a little quartz as well as non-crystalline silica, and with the latter it is difficult to bring all the amorphous silica into solution. I t follows, therefore, that the work of Von Piedzicki, who determined the proportion of free silica in soils by boiling the samples’ for an hour and a half with 10 per cent. sodium hydroxide, is valueless. The separation, however, may be effected by the use of solutions of methylamine or, preferably, diethylamine. A 33 per cent. solution of diethylamine dissolves 0.6 gramme of amorphous silica to within 0.0002 gramme, if it is boiled therewith for about eight hours, and a 16.5 per cent.solution of msthylamine acts similarly. (cf. ANALYST, 1898, xxiii., 84.) F. H. L. Estimation of Bromine by means of Bromate Solution. W. Vaubel. (Chem. Zeit., 1902, xxvi., 1220.)-Since the hydroxyl and amido groups which exist in the ortho or para positions are rapidly displaced by bromine in acid solution from124 TEE ANALYST. bodies like phenol and the amines, while chlorine only acts in a similar fashion slowly, it might be thought that a mixture of potassium bromide and chloride could be analysed by adding standard potassium bromate solution in presence of a phenol and an acid until a reaction is obtained with potassium iodide starch paper- However, although potassium bromide, or bromine water, can be andysed in the nmnner indicated if sulphuric acid is used, the process does not work in the presence of hydrochloric acid, presumably because the bromine substitution product already formed increases the power of the phenol or aniline to take up chlorine.The Same method is nevertheless available for the titration of phenol and aniline, because an excess of bromide is always present. When it is employed, in the absence of hydrochloric acid, for the estimation of a bromide, only one-half the volume of bromate required must be calculated from, because the other half is used up in the formation of the tribromophenol derivative. F. H. L. The Detection of Hydrocyanic Acid in the Presence of Sulphocyanic, Wdroferrocyanic, and Hydroferricyanic Acids and their Salts.Louis E. Prsiss. (Amer. Chenz. Journ., xxviii., 240.)-All metals, except those belonging to the alkali group, are first removed by boiling with sodium carbonate sohtion. Ch-”tic potash and about 0.5 gramme aluminium filings are then added to the liquid As soon as a test with ferrous sulphate shows r e d u h ~ n to be compIete, which is usually the case after fifteen minutes, the solution is acidified with hydrochloric mid, and mercuric chloride added to precipitate the hydroferrocyanic acid. After shaking for a few minutes in the cold, the precipitate may be filtered off and washed with a little mercuric chloride solution. ?he solution is next made alkaline with caustic potash, the precipitated mercuric oxide filtered off, and the filtrate heated to boiling with a little ferrous sulphate, after which it is again filtered, acidified with hydrochloric acid, and ferric chloride solution added.After decolorizing any sulphocyanide formed by means of mercuric chloride, the blue Colour or precipitate due to the Prussian blue becomes apparent if any cyanide was present in the original substance. reduce any ferricyanide. A. G. L. Analysis of Cyanide Fume. L. Schneider. (Oesterr. ,%?its. Berg. U . Hiittenw., 1902, I., 498; through Chem. ,&it. Rep., 1902, 281.)-This dust contains the follow- ing cyanogen compounds : Potassium ferrocyanide, thiocyanate, cyanide, and cyanate. These may be recovered by passing it through water, when the solution also contains potassium hydroxide, chloride, and carbonate.To estimate the cyanogen compounds the liquid is made alkaline with ammonia, and silver nitrate is added; the ferrocyanide is filtered off, washed, dried, and the silver in it deter- mined by the dry process. The amount of ferrocyanogen can also be checked by an iron estimation. Part of the filtrate is acidified with nitric acid, when silver cyanide, chloride, thiocyanate, and cyanate fall. This precipitate is warmed with aqua regia, and in the filtrate the sulphuric acid coming from the thiocyanogen is determined. Another portion of the ammoniacal liquid is acidified and the silver salts collected ; these are then digested for one hour at 100” C. with 10 C.C. of nitric acid and 200 C.C.THE ANALYST. 125 of water ; silver thiocyanate, cyanide, and chloride remain undissolved ; potassium cyanate appears in the solution.To the filtrate hydrochloric acid is added, and the amount of silver chloride, which corresponds with the original cyanate, is ascertained. If the above-mentioned precipitate is heated for one hour at 100" C. with strong nitric acid (1 : I), the silver from all the cyanogen compounds passes into solution, except that of the chloride and the yellow silver perthiocyanate ; so that the silver chloride thrown out of the hot filtrate corresponds with the original thiocyanate, cyanide, and cyanate. The silver cyanide can thus be estimated by difference. It may, however, be determined by mixing the aqueous extract of the fume with ammonia, and ammonium carbonate, precipitating the ferrocyanogen with silver, treating the filtrate with potassium iodide, shaking, and filtering.Only silver cyanide remains in solution, and its amount can be deduced from the silver chloride obtained on acidification with hydrochloric acid. F. H. L. The Volumetric Determination of Nitric Acid. J. I(. Phelps. (Zeits. Anoyg. Chern., xxxiii., 357.)-The author's method, which is a modification of Holland's (Chem. News, xvii., 219), depends on the oxidation, in an atmosphere of steam, of a ferrous salt by the nitric acid in the presence of hydrochloric acid. The apparatus used consists of a 250 C.C. flask closed by a double-bored rubber stopper, carrying a tap-funnel with constricted stem and a short wide tube bent over downwards outside the flask, to serve as exit tube. By dipping the end of this tube into mercury contained in a test-tube, it is possible to increase the pressure in the flask.To carry out a determination, the solution containing the nitrate is placed in the flask, the stem of the tttp-funnel filled with water, and the tap closed, after which the solution is boiled down to a volume of about 10 c.c., the exit tube being kept 3 centimetres below the surface of the mercury. After the air has thus been expelled from the flask, a known volume of standard ferrous sulphate solution in fairly large excess is drawn into the flask by allowing it to cool slightly, and raising the exit tube in the mercury. A quantity of concentrated hydrochloric acid, about equal in volume to the contents of the flask, is then added in the same way, and the whole boiled down to a volume of 10 or 15 c.c., to insure thorough reduction of the nitric acid, the exit tube being kept only just below the surface of the mercury during this boiling.The excess of acid is then neutralized by means of sodium carbonate, the flask allowed to cool, and the excess of ferrous sulphate determined with potassium permanganate or iodine and arsenious oxide solutions. The method gives very satisfactory results. For exact work, ammonium salts must be absent, and hence ammonium ferrous sulphate should not be used in place of ferrous sulphate. A. G. L. Notes on the Iceland Spar Method for Standa.rdizing of Hydrochloric Acid. W. Heber Green. (Chem. News, lxxxvii., &)--The author has used this method, which was proposed by Masson (Chem.News, lxxxi., 73), for the last three years, and finds it superior to any other. The use of a pipette instead of a burette is recommended for the measurement of the acid, the average error of a 20 C.C.126 THE ANALYST. pipette carefully freed from grease by means of an alcoholic soap solution being only 0.003’ C.C. The beaker used should be of Jena glass, and should be boiled for three or four hours in acidulated water before being used, since after this treatment its weight remains practically constant even when expmed to the action of the hydro- chloric acid and calcium chloride solutions. Finally, the molecular weight of calcium carbonate may be safely assumed as 100.0 (0 = 16) for this determination, since the error in the measurement of the acid is greater than the uncertainty in the atomic weight of calcium.A. G. L. Estimation of Perchlorates. M. Honig. (Chem. Zeit., 1903, xxvii. , 32.)-If the material to be analysed is a salipetre, and does not contain more than 5 per cent. of perchlorate, 5 to 10 grammes of it are taken; but in other cases the sample is diluted with sodium or potassium nitrate free from chlorine till the proportion of perchlorate does not exceed that limit, and 5 or 10 grammes of the prepared substance are melted in a small nickel crucible over a gas-burner, which brings the mass to quiet fusion without causing the ’ vessel to be visibly red. Next 2 to 3 grammes of iron filings are added and stirred i n ; the crucible is covered with a watch-glass and kept over the flame for half an hour, stirring at intervals.Finally, the melt is cooled, taken up in warm water, filtered, and the chlorine determined gravimetrically. Powdered zinc, aluminium, and lead (already recom- mended by Selckmann) are less convenient reducing agents, for the mixtures obtained with them are less fluid unless the temperature is pushed to a point where volatili- zation of chlorine is probable. Tin acts too energetically unless the perchlorate is diluted with a carbonate, and its salts are troublesome in after-analysis. Magnesium reduces the perchlorate with almost explosive violence, even when the diluent is a carbonate. The examples quoted show maximum errors of -1-0.8 and - 1.1 milli- gramme when estimating amounts of potassium perchlorate up to 0.497 gramme in weight.F. H. L. On the Solubility of Boric Acid i n Hydrochloric Acid. W. Herz. (Zeits- Anorg. Chem., xxxiii., 355.)-The author has made some experiments to see whether the statement in Dammer’s ‘‘ Handbuch der Anorganischen Chemie ” to the effect that boric acid is more soluble in hydrochloric acid than in water is correct, and finds, on the contrary, that the opposite is true, the solubility steadily diminishing with increasing concentration of the hydrochloric acid. The solubility of boric acid in pure water was found to be 0.907 gramme-equivalents per litre; while in 9.51 normal hydrochloric acid the solubility is only 0.338 gramme-equivalents. A. G. L. __ - _ _ _ _ - On the Simultaneous Volumetric Determination of Boric Acid and Strong Acids. W. Herz. (Zeits.Anorg. Chem., xxxiii., 353.) - In solutions containing boric acid together with some strong acid both may be determined volumetrically as follows : The quantity of standard sodium hydrate solution required to give a neutral reaction to the solution, using nitro-phenol as indicator, is first ascertained. Nitro-THE ANALYST. 127 phenol, which is yellow in alkaline and colourless in acid solution, is not affected by boric acid, and hence the quantity of sodium hydrate found above corresponds to the strong acid present. Mannitol and a few drops of phenolphthalein solution are then added to the liquid, and the titration continued to the appearance of the pink colour, the quantity of sodium hydrate now used corresponding to the b6ric acid in the solution. A. G. L.~ _____ A Rapid Method for determining Sulphur in Coal and Coke. Carl Sund- strom. (Jozcm. Amer. Chem. Xoc., xxv., 184.)-Sodium peroxide is used as the oxidizing agent. In analysing coke, 0.7 gramme of the finely-powdered sample and 13 grammes dry sodium peroxide are intimately mixed in a 30 C.C. nickel crucible. A 3-inch fuse is inserted in the mixture, the crucible covered, supported on a triangle, and placed in about 9 inch of water; the fuse is then lit, and after three or four minutes, crucible and cover are placed in a small beaker with 30 C.C. water. As soon as solution has taken place, crucible and cover are removed, the solution is made acid with hydrochloric acid, and filtered ; in the filtrate, sulphuric acid is precipitated as usual. The fuses used are made by treating cotton wick with a mixture of 1 part fuming nitric acid and 2 parts sulphuric acid at 15' C. for twelve hours, washing in running water for twelve hours, drying at the ordinary temperature, then soaking in cold, nearly saturated potassium nitrate solution for an hour, pressing out the excess of solution, and again drying at the ordinary temperature.In analysing coal, the oxidation is effected in a small cylindrical steel bomb, the dimensions of which are : Internal diameter, la inches ; internal depth, I& inches; sides, bottom, and flange, Q inch thick; cover-plate, qK inch thick and 1% inches diameter. The cover does not touch the clamp, and is insulated from the bomb by a thin mica gasket, and from the screw by a piece of ordinary red fibre.For the deter- mination, 0-7 gramme of the coal and 13 grammes of sodium peroxide are mixed in the bomb, and compressed by means of a small vice. A thin iron wire, 4 inches long, is then inserted, one end being under the mica, touching the bomb, the other above the mica, in contact with the cover, the wire being looped so as to touch the mixture inside. A current of 4 ampAres is used to start the reaction, one terminal being applied to the cover, the other to the bomb. The product of the reaction is treated as for coke. The above methods give results practically identical with those given by Eschka's method in much less time and with cheaper apparatus, while there is also less chance of the in troductioa of extraneous sulphur. A. G. L. Determination of Selenium in Organic Compounds.H. Frerichs. (Arch. Phctrm., 1902, ccxl., 656 ; through Chem. Zed. Rep., 1903, 22.)-The organic matter in about 0.2 or 0.3 gramme of the sample is destroyed by the Carius process, by treating it with 1.4 nitric acid and about 0.5 gramme of silver nitrate. The mass is then brought into a porcelain basin by the aid of water, and evaporated to dryness. The residue is rubbed down with a few drops of water, rinsed on to a filter with128 THE ANALYST. alcohol, and washed with the latter as long as silver exists in the filtrate. The paper and precipitate are next transferred to a beaker, and boiled with 20 C.C. of nitric acid and 80 C.C. of water for about five minutes until everything has passed into solution. The liquid is diluted with 100 C.C.of water, mixed with 1 C.C. of a strong solution of iron-ainmonium'alum, and titrated with decinormal potassium thiocyanate. One C.C. of the latter corresponds with 0.00395 gramme of Se. The results are accurate. (Cf. this volume, p. 44.) F. H. L. Calculation of the Calorific Power of Coal. Goutal. (Ann. de Chim. anal., 1903, viii., 1-4. )-The formula originally proposed by the author: (Ann. de Chirn. anal., 1896, 169) was modified by De Paepe (ANALYST, xxiv., 107), who applied it to a wider range of coa,ls. Since then the author has examined more than 600 samples, and has found that the calorific power can be calculated with suficient accuracy for industrial purposes by means of the formula P = 82C + aV, where P represents the calorific power, C the percentage of fixed carbon, V that of the volatile substances, and n a factor depending upon the proportion of volatile substances. The author has plotted a curve of experimental results to determine the value of this factor, and from this has obtained the following values : Coal containing volatile Corresponding value of substances per cent. 5 10 15 20 25 30 35 38 40 a in calories ... ' ... 145 130 117 109 103 98 94 85 80 In the case of anthracite coals a is represented by a constant equal to 100 calories, and the formula becomes P = 82C + 1OOV. The difference between the values thus calculated and those actually determined is stated to rarely exceed 1 per cent., though in the case of certain anthracite or lignite coals it may exceed 2 per cent. The moisture is determined on 2 grammes at 110" C. ; the volatile substances by drying 2 grammes of coal and heating it in a covered platinum crucible over a Buasen burner, until flames no longer appear between the crucible and its cover, and then rapidly cooling the sample in a desiccator; and the ash by slow combustion in a muffle (cf. ANALYST, xxi., 21). C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN9032800120

出版商:RSC    

年代:1903

数据来源: RSC

摘要:

128 THE ANALYST. APPARATUS. A New Pyknometer. C. N. Riiber. (Chew. Zeit., 1903, xxvii., 94.)-The apparatus figured in the accompanying sketch is claimed to exhibit two chief advantages over other pyknometers. First, the liquid-.is brought to the temperature of observation in the separate flask A, this hastens the process much, and the pyknometer itself is not liable to become damp during a warming or cooling process ;THE ANALYST. 129 secondly, it is provided with a counterpoise C, which has exactly the weight of the pyknometer when filled with water at the standard temperature, and has also the same external volume as the pyknometer, so that, with the exception of the weights themselves (which in ordinary work may be neglected), the masses laid on each pan of the balance are identical, and corrections for displaced air, which are necessary if the results are to be exact to the fourth decimal place, are not required. The pyknometer contains 20 C.C.between the mark a on the right-hand tube and the point of the capillary b ; a cap is used to cover a if the liquid is very volatile. The flask A holds about 70 c.c., and in it the liquid is adjusted in temperature. By aspiration the pyknometer is filled a first time in order to bring the glass to the correct temperature; and then the liquid is allowed to run out, adjusted in temperature once more, made to fill B as before, and the excess withdrawn by applying a piece of filter-paper to the point b. The instrument easily gives an accuracy of O’OOO1 ; and if if is provided with an evacuated glass jacket its delicacy may reach 0.00001.I t is made by Sauer and Gockel, of Berlin, W. F. H. L. A Modification of Thorne’s Receiver for Distillations in Vacuo. Zd. H. Skraup. (uonatshe,t’te f. Chem., xxiii., 1162.)- The advantage claimed for this piece of apparatus is its simplicity. The end A of the receiver shown in the figure is connected to the distillation flask, the side-tube B to the pump. The tap D has one very wide bore; E is a three-way tap by means of which air may be admitted to the bottle. This is connected by B rubber stopper, which remains on the tube when the bottle is changed, which opera- tion is greatly facilitated by moistening the inside of the neck of the new bottle with a drop of the distillate. The rest of the manipula- tion is evident froffi the figure.I r;iD A. G. L.130 THE ANALYST. C. Schmitz’s Portable Apparatus for Gas An&lysis. (Chem. zed. 1902, xxvi., 1202.)-This apparatus has been specially designed for safe transport, and for con- venience in use by not requiring any dis- mounting of its parts. The filtering vessel e communicates at its right-hand end with the inlet rubber tube d, and at the left, past the three-way cocks at the top of each absorp- tion vessel and the burette, with the aspirat- ing ball g. By this arrangement practically all the gas left in the apparatus from a pre- vious test can be swept out before a fresh charge is admitted. The burette a is joined to its jacket, which contains water, by fusion. The absorption vessels, each filled with glass tubes, are also jacketed, and the reagents, admitted through the rubber tubes at the base of each, enter into the annuli. The necessary reagents are stored in bottles fitted with wired-clipped stoppers, which stand in separate compartments of the case. A t the point h in the case is a movable clip which carries both the inlet tube and the tube lead- ing to the aspirator; when this is drawn forwards the tubes extend horizontally and sideways from the case, and are held so that they cannot become kinked ; when the case is to be closed the clip is pushed back. The bottle .i goes into the space 0. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN9032800128

出版商:RSC    

年代:1903

数据来源: RSC

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130 THE ANALYST, APPEAL CASE UNDER THE FERTILIZERS AND FEEDING STUFFS ACT. KING’S BENCH DIVISION. (Before the LORD CHIEF JUSTICE OF ENGLAND, MR. JUSTICE WILLS, and MR. JUSTICE CHANNELL.) (From the “ Times ” of March 27, 1903.) KORTEN 2). WEST SUSSEX COUNTY COUNCIL. THIS was a case stated by Alderman Smallman, sitting at the Guildhall Justice Room, in the following circumstances : An information was preferred by the respondents against the appel- lant under the Fertilizers and Feeding Stuffs Act, 1893, charging that “ The Chemical Works, late H. and E. Albert,” sold to the Sheppy Glue and Chemical Works (Limited), as a fertilizer, 17 tons Thomas Phosphate Powder, and unlawfully caused or permitted an invoice or descrip- tion of the same to be given to the purchaser which was false in a material particular to the prejudice of the purchaser, in that it described the article as containing 38 to 45 per cent.total phosphates, and that the appellant abetted the offence. The following facts appeared from the case : The appellant was the managing director inTHE ANALYST. 131 London of a company trading as ‘‘ The Chemical Works, late H. and E. Albert.” The company entered into a contract with the Sheppy Glue and Chemical Works (Limited) for the sale of Thomas Phosphate Powder, and in accordance with request sent 17 tons on November 8, 1901, from their factory at Wednesbury to Mr. J. W. Stevens, at Petworth, Sussex. An invoice describing the goods as containing 38 to 45 per cent. of total phosphates was sent to the Sheppy Company. Mr.Stevens sold the powder to Mr. Watson, estate agent of Lord Leconfield a t Petworth, by whose orders it was delivered to certain farmers, each of whom took samples, which Mr. Watson caused to be analysed by an analyst, who was not the district analyst nor the chief analyst under the Act. The analyst reported that the samples contained only 31-15 per cent. of total phosphates. Other samples were taken, the analysis of which showed 30.76 and 30.52 per cent. The samples were not taken in accordance with the regulations made by the Board of Agriculture under the Act, nor were the samples a t any time submitted to the district analyst. The magistrate found, as a fact, that the description in the invoice that the powder contained 38 to 45 per cent. total phosphates was false.It was proved that the appel- lant was cognisant of the form of invoice; that he signed certain letters dealing with the 17 tons; and showing he knew basic slag to contain proportions of phosphates which might have to be ascertained in a particular way; that in the ordinary way sales of basic slag would come under his notice, and that invoices with a guarantee would not be sent out in the ordinary course without his knowledge. There was no evidence that he saw the particular invoice sent out from the London office or that he otherwise knew the contents to be false ; but there was evidence that the invoice in question would not be sent out in the ordinary course without the appellant’s knowledge. The questions for the Court were whether the magistrate was right in holding (1) that compliance with the Act (particularly Section 5 ) as to taking samples and analysis, and with the regulations of the Board of Agriculture were not conditions precedent to a prosecution under the Act, and (2) that there was evidence that the appellant abetted the offence of causing or permitting the invoice to be false in a material particular to the prejudice of the purchaser.The magistrate, having so held, fined the appellant 40s. and 25 guineas costs. Mr. Avory, K.C., and Mr. Chalmers were for the appellant; Mr. Herbert Smith was for the respondent. The LORD CHIEF JUSTICE, in giving judgment yesterday, said that on one of the points raised he had very great difficulty. The first point was whether the prosecution could be maintained at all, because the samples upon which the magistrate came to the conclusion that the stuff did not contain the guaranteed amount of phosphates had not been taken in the way contemplated by the Act.If the buyer or the person prosecuting had purported to rely on Subsection (5) of Section 5, for the purpose of proving his case, Mr. Avory’s point would be a very good one. But it was impossible to say that the taking of a sample by the buyer and submitting it to the analyst was a condition precedent to a prosecution. There was nothing that corresponded with Section 20 of the Sale of Food and Drugs Act, 1875 ; but he thought that the argument of Mr. Herbert Smith was well founded, that Section 7 only imposed a condition that might involve samples being taken and analysis made in a certain way in the case of a prosecution ‘&by the person aggrieved or by any body or association,” and it could not be said that where there was a prosecution by the County Council there was any necessity for samples being taken or analysis made in a particular manner.I t was open to argument whether there might not be cases of sending a false invoice or false description which did not require any analysis at all. Whether the samples were satisfactorily taken was a question of fact for the magistrate. Therefore the first point, that there was a necessity for the samples to be taken in a particular way as a condition precedent to the prosecution, failed. It was suggested for the appellant that, as the statement in the invoice that the stuff contained 38 to 45 per cent.of phosphates as a percentage must be a matter of uncertainty, there was no The next point was not directly raised, but was involved in the questions submitted.132 THE ANALYST. evidence of an invoice false in any material particular. He thought that that point was not a good one. The Act intended that the prima facie description of the percentage should be a warranty, and that it should be an offence if an invoice contairing that warranty was not delivered with the article. The particular invoice contained certain clauses, put in for the protection of the seller ; but they were not sufficient to negative the view that there was on the face of this invoice a warranty that there was a minimum of 38 per cent., and they did not prevent that guarantee from being an invoice or description false in a material particular.On the last point of the case he felt the gravest doubt-namely, on the question whether there was any evidence on which the managing director could be convicted of abetting the offence of causing or permitting the invoice to be given. He was cognisant of the form of invoice such as was used in the present case. He signed letters proving that he knew that basic slag contained various proportions of phosphates that might have to be ascertained in a particular way. Sales of basic slag would come under his notice, and it would not be sent out with a guarantee without his knowledge; but there was no evidence that he saw the particular invoice. The difficulty was whether it was necessary that there should be evidence that the person charged knew of the sending out of the particular invoice.After great doubt, which was not altogether removed, he concluded that there was evidence on which this gentleman could be convicted. The Act was passed for the protection of purchasers, who in nine cases out of ten would not take steps to hare an analysis made. The manager must be taken to know that with every parcel sent out there must go an invoice stating the minimum percentage of phosphates. I n Section 3 (1) (6) “ false ” meant “ untrue.” The word ‘‘ causes ” in that subsection did not create great difficulty, but the wider word “ permits ” had been put in. One had to face the view that, unless there was an express statement or necessary implication to the contrary, for a criminal offence guilty knowledge was, as a rule, necessary.The exceptions would be found in “ Sherras w. De Rutzen ” (1895, 1 Q.B., 918). His Lordship had come to the conclusion that “ permit ” was inserted to include the case of a false description that had been sent out by the permission of the person managing the works from which the goods were sent. I t might be said that he did not permit the description to be false in the sense of allowing this particular description to be false. To found an argument on the curious form of that subsection would be to defeat the Act. Section 3 (1) ( b ) was meant to indicate that a person causing or permitting to be sent an invoice in fact false was guilty of an offence. He had come to the conclusion that there was evidence that the manager caused or permitted a false invoice to be sent, and the appeal must be dismissed. Mr. JUSTICE WILLS was of the same opinion, but he did not feel the saiiie difficulty as to Section 3 (1) ( b ) . There was a great body of modern legislation in which, for the benefit of the community, offences were constituted to which the doctrine of mens rea was not intended to apply. His Lordship thought, from the general nature of the Act and the mischief it was intended to meet, that it was not intended that a guilty mind should be an ingredient in the defence. Mr. JUSTICE CHANNELL was sgreed as to the result ; but as to Section 3 (1) ( b ) he could not agree that men8 rea was not a constituent element of the offence. However, he agreed with the magistrate that there was evidence that the appellant allowed the statement to be made in the invoice without taking any steps to ascertain whether it was true. That was Section 3 (1) (a). The appeal was accordingly dismissed.

ISSN:0003-2654    

DOI:10.1039/AN9032800130

出版商:RSC    

年代:1903

数据来源: RSC