摘要:

THE ANALYST. 287 TOXICOLOGICAL ANALYSIS, The Detection and Estimation of Free Phosphorus in Oils and Fats. E. Loui'se. (Comptes Reizd., 1899, exxix., 394, 395.)-The methods used for the detection and estimation of phosphorus in toxicological work are not available when only traces of phosphorus are present in a large amount of oil. For it cannot be volatilized in a short time with vapour, whilst if the current be continued too long some of the phosphorus will be oxidized and left behind. Other methods based on the oxidation of the phosphorus are, in the author's opinion, also inapplicable under these circumstances.288 TRE ANALYST. This difficulty may be obviated by diluting the oil with acetone and precipitating the phosphorus by means of a comentrated solution of silver nitrate. Five grammes of the oil are made up to 100 C.C. with acetone and the liquid divided into 10 portions. To the first of these is added 1 drop of a 10 per cent. solution of silver nitrate, the liquid filtered, and the filtrate again tested with silver nitrate, If a coloration be obtained, the second tube is tested with 2 drops of the silver nitrate solution in the same way, and so on until the point is reached at which the precipitation is complete. Say, for example, that 2 drops have been found insufficient and 3 too many, Two drops of the 10 per cent. solution are then added to a fresh portion and the intermediate point determined by means of a 1 per cent, solution of silver nitrate. I n this way traces of phosphorus in oil can readily be determined in terms of standard silver nitrate. C. A. M.

ISSN:0003-2654    

DOI:10.1039/AN8992400287

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

288 TRE ANALYST. ORGANIC ANALYSIS. Influence of Temperature on the Specific Rotation of Sucrose, and Method of correcting Readings of Compensating Polarimeters. ( JOZLWZ. Amer. Chem. SOC., vol. xxi. [7], pp. 568-596.)--From the results furnished by a number of carefully-performed experiments on the alterations in the specific rotation of sucrose under the influence of temperature, and on the various factors affecting the same, all of which are given in detail, the author concludes that the mean varia- tion for each degree C. is 0.00994, the specific rotatory power at 17.5" C. being 66.547, whilst at 4" and 40" (the limits of temperature investigated) the readings were 66.657 and 66.299 respectively; i.e., the variation is in inverse ratio to the Gemperature. It appears, however, that the variations are not uniform, the rate of decrease being greater (nearly double), between 15" and 17.5"; 20"-25" and 30"-35" C.than elsewhere in the series. c. s. H. W. Wiley. The Estimation of Mannose in the Presence of Other Sugars. E. Bourquelot and H. Herissey. (Joz~m. Pharm. Clzinz., 1899, x., 206-209.)-The authors have devised a method for the estimation of mannose, founded on the insolubility of its hydrazone in cold water, which in its general principles is the same as that worked out by Lintner and Krober for the estimation of dextrose, laevulose, and sacchnrose (ANALYST, xx,, 167). They find that the results are accurate if the temperature be kept sufficiently low, and the solution contain from 3 to 5 per cent. of mannose. With weaker solutions the weight of the osazone is too low by about 0.04 to 0-05 gramme for each 100 C.C.of solution. The method is stated to be specially applicable to the determina- tion of mannose in the products of the hydrolysis of vegetable substances where the mannose is frequently accompanied by galactose, arabinose, and compounds allied to dextrins. The following examples may be quoted to show the authors' method of working, and the results obtained in test experiments : A solution of crystalline mannose (0.8 gramme) and galactose (1.20 grammes), inTHE ANALYST. 289 33.2 C.C. of water, was mixed with a solution containing phenylhydrazine (2.4 c.c.) and glacial acetic acid (2.4 c.c.) in 12 C.C. of water. The mixture was left for eight hours at a temperature of 10" C., and the precipitated osazone washed successively, on a double filter with the aid of a pump, with 10 C.C.of ice-water, 10 C.C. of alcohol, and 10 C.C. of ether, dried at 100" C. and weighed. The amount of osazone found was 1.195 grammes, as compared with the theoretical quantity, 1-20 grammes. I n like manner a mixture of 0.8 grammes of mannose and 1.20 grammes of arabinose yielded 1.195 grammes of osazone; and a mixture of mannose (1 gramme) and crude maltose containing dextrin (1 gramme), yielded 1.44 granime, as against the theoretical amount, 1-50 gramme. C. A. M. The Determination of Albuminous Substances in Urine. G. Denigba. (Joz~rn. Pharrn. Chim., 1899, x., 97-102.)-The method described here is an application of the author's method of estimating casein in milk (ANALYST, xxii., 11, and xxiii., 38).Although the weight of proteid precipitated is not proportional to the mercury com- bining with it, it is possible to make a correct estimation, when the amount of albumin in the urine required for the analysis (150 c.c.) does not exceed 15 to 16 centi- grammes. Twenty C.C. of the mercuric reagent are mixed with 2 C.C. of glacial acetic acid, and after the addition of 150 C.C. of the urine, which must not contain more than 1-10 gramme of albumin per litre, the liquid is made up to 200 C.C. and filtered. Of this filtrate 125 C.C. are added to 25 C.C. of an ammoniacal solution of potassium cyanide equivalent to 2G silver nitrate, the liquid filtered after two or three minutes, and 120 C.C. of this second filtrate titrated with decinormal silver nitrate solution until a faint but permanent turbidity results.The number of tenths of a C.C. (n) required, less the constant 48, gives directly the number of decigrammes of albumin in a litre of the urine. In the case of there being impurities in the reagent, the constant required may not be exactly 48. This should be determined by mixing 10 C.C. of the mercuric reagent with 20 C.C. of the cyanide solution and 100 C.C. of water, and adding deci- normal silver nitrate until there is a permanent turbidity, the number of tenths of a C.C. used giving the necessary constant. If the urine contain more than 1-10 gramme of albumin per litre, it must be so diluted that not more than that proportion is present. The author's mercuric reagent is prepared by dissolving 13.55 grammes of mercuric chloride and 36 grammes of potassium iodide in 100 C.C.of cold water, and diluting the solution to a litre. This method is not applicable when the urine contains less than 20 centigrammes per litre, and the author therefore recommends the following process in such cases : An albuminous urine, the albumin in which has been previously determined gravi- metrically, is distributed throughout a series of five tubes in such a manner that they contain albumin in the proportion of 1, 2, 4, 8 and 12 centigrammes per litre respec- tively. The liquid in each is diluted to 10 c.c., and 10 C.C. of the urine under examination is placed in a sixth tube. After the introduction of 2 C.C. of a 5 per cent.290 THE ANALYST.solution of sodium metaphosphate, and 4 drops of sulphuric acid into each, the tubes are placed for five minutes in boiling water, and the opalescence in the sixth tube compared with that in the standard tubes. This method gives good results with urine containing not more than 12 centi- grammes of albumin per litre, but above that quantity the precipitate formed in the tubes on warming is of a flocculent character. Therefore, in the examination o€ urines containing between 12 and 20 centigrammes per litre there must be a suitable dilution. When globulins are present in the urine, the total albuminous substances are estimated as described above, before and after saturation with magnesium sulphate, which removes the globulins. Two determinations are also necessary in the presence of alkaloids or peptones, viz., before and after the removal of coagulable albuminous substances by heat.C. A. M. A Reaction for Benzidine and Tolidine. J. WolK (Am. de Chim. Anal., 1899, iv., 263-264.)-A small portion of the substance under examination is dissolved in 1 C.C. of cold glacial acetic acid, the test-tube filled to about three-quarters with water, and a few drops of water, with lead dioxide in suspension, introduced. A bright blue colour is immediately produced, which lasts for some time, but disappears on heating. If to the solution of either of these bases in dilute acetic acid a few drops of bromine be added, there is a blue coloration, and on continuing the addition of bromine a blue precipitate is formed. The colouring matter thus obtained is stable at the ordinary temperature; it is insoluble in water and in alcohol.The colour disappears on adding ammonia, but reappears on again acidifying with acetic acid. In the presence of dilute mineral acids the oxidation of benzidine or tolidine does not give any blue coloration. The colour is obtained, though with less intensity, in the presence of dilute solutions of other organic acids such as citric, tartaric, and oxaJic acids. C. A. M. Determination by Combustion of Carbon and Hydrogen in Organic Substances containing Nitrogen. 0. F. Tower. (Journ. Anzer. Chem. SOC., vol. xxi. [7], pp. 596-605.)-From the results obtained in the investigations described, it appears that, in the case of amido-compounds, there is no need to use a copper spiral in the combustion-tube, since no oxides of nitrogen absorbed by concentrated sulphuric acid or by soda-lime are formed, whilst of the nitro-substances (nitraniline, dinitro- benzene, and picric acid) examined, only the last-named gave off oxides-probably for the most part nitrogen peroxide-absorbed by the reagents.The formation of nitric oxide is not impossible, but as it is not absorbed unless further oxidized, it does not affect the accuracy of the determination of carbon and hydrogen. C. S.THE ANALYST. 291 (Bull. SOC. Chim., 1899, xxi., 798-800.) -The author supplements the work of A. and P. Buisine (ANALYST, xxiv., 214), which dealt principally with suint oils, by analyses and remarks on the composition of pyrolignite oils. These are much less regular as regards the percentage of the various constituents.Thus, two samples contained about 23 per cent. of substances distilling below 90" C., and from 60 to 66 per cent. distilling between 90" and 110" C. ; while two other samples of different origin contained only 30 to 35 per cent. of the former, and 27 to 35 per cent. of the latter constituents. The following analyses are given to show the composition of three samples of acetone oil manufactured from gray acetate of lime, which the author found to contain only traces of propionates-a fact which accounts for the almost complete absence of methyl isopropyl-ketone and methyl propyl-ketone in the distillation products. The third sample was washed several times, as is customary in most Notes on Acetone Oil, R. Duchemin.French factories : I. Distilling between Per Cent, O c. 63- 70 20 cent. 70- 75 75- so 80- 85 85- 90 90-110 2-J Above 110 27 100 } 42 i: Insoluble in Insoluble in bi- * water ... tion ... ... -- ~ 70- 80 5 70" to 90°, 17 70" to 90", I 80- 85 4.l 18 per 2 41 per 85- 90 10 cent. 90-110 Above 110 80 39 I 100 -- iInsoluble in 1- 100 1 water ...I 70 -- iInsoluble in bi-1 76 48 2 ~ sulphite ...I 33 % 9 1 cent. _- 4 2 The variations in composition of commercial pyrolignite acetones are therefore to be attributed partly to difference in the composition of the calcium acetate and partly to the amount of washing which the acetone has received. According to the author, these oils can only contain traces of methyl propyl-ketone, but may contain up to 50 per cent. of their weight of products distilling below 90" C., and in particular of methyl ethyl-ketone. C.A. M. On Hazel-nut Oil. J. Hanus. (Zeit. fiir Undersuch. der nTahr. und Genz6ss- mittel, 1899, ii., 617-622.)-This oil is contained in the hazel-nut (CoryZZzcs avellana L.) to the extent of from 50 to 60 per cent. In the following table the constants found by the author are given side by side with those already published by other chemists, for comparison :292 THE ANALYST. Hanus. I. Natural oil : Specific gravity at 15" C. ... Saponification number Iodine number . . . ,.. 90.20 Hehner number . . . ... 95.60 Reichert-Meissl number . . . 1 0.99 Acetyl number . , . ... 3.2 Glycerin per cent. ... 10.41 11. Insoluble fatty acids : Saponification number , . , ' 200.6 Iodine number . , .... 90-60 Mean molecular weight . . . '279.0 111. Unsaturated fatty acids: 1 Saponification number . . . 198.50 Iodine number . . . ... 91.30 Mean molecular weight . . , ~ 282.0 Maumen6 number . . . ... 1 36.2 0.9169 . . . 1 193.7 Schadler. 0.9243 Filsinger. 0.9146 197.1 - - I 0.917 ~ 0.9164; 0.916 192.8 ~ 191.4 ! 187.0 86.3-86.9 83 2 1 87.0 - I - , 95.50 1 0.99 - \ - - - - I The results of the analysis of the oil are as follows: Oleic palmitic and stearic acids 10 per cent., glycerin (calculated from number) 10-41 per cent., and phytosterin 0.50 per cent. acid 85 per cent., the saponification H. H. 13. S. The Examination of Wood-Tar Creosote. L. F. Kebler. (Amer. Jount. Plzarnt., 1899, lxxi., 409-413.)-The composition of commercial creosote varies with the kind of wood employed for the distillation, and the methods employed for removing the creosote from the distillate.It consists of a mixture of phenoloid compounds, chiefly of several homologous series, and any of the following compounds may be met with : Phenol (boiling-point, 182" C . ) ; paracresol (203" C.); xylol (220' C.) ; guaiacol (200" C.) ; crcfol (219" C.) ; homocrejol, or dimethyl-guaiacol (230" C.) ; and ccerulignol, or propyl-guaiacol (241" C.). Wood-tar creosote was formerly regarded as consisting in the main of guaiacol and cresol, but at the present time the author states that it is difficult to purchase creosote containing more than 20 per cent. of guaiacol; and he regards the high per- centage found by some chemists as being probably due to faulty methods of analysis.The differentiation of different kinds of creosote is uncertain. Hirschsohn (Phurm. Zeit. RZLSS., 1898, xxxv., 801) Bas described tests to distinguish beech-wood tar from the tars of birch, fir, and juniper ; but, in the author's experience, the tests which will identify the unmixed products are uncertain in the case of mixtures. Oak-wood creosote is much more caustic than beech-wood creosote, owing t o the fact that the former contains a larger amount of monophenols and correspond- ingly less guaiacol than the latter. The proportion of cresol and its homologues is the same in both. Pine-wood creosote (Cowzptes Rend., cxix., 1276) distilling between 200" and 220" C., has been found to contain 40 per cent. of monophenols, 20.3 per cent.of guaiacol, and 37.5 per cent. of cresol and its homologues.TEE ANALYST. 293 As regards the specific gravity of creosote, the United States Pharmacopoeia fixes the lowest limit at 1.070, at 15" C, : while the British Pharmacopceia requires it to be not lower than 1.079, at 15" C. According to the author, the former limit can be readily met by a creosote which does not contain any guaiacol, and in his opinion the American standard should be raised. The following analyses of six samples from different American makers are given to show that it is possible to judge. as to the quality of a creosote by an analytical examination : Per Cent. of Substance distitling between the following Temperatures. C. corrected. -,\ -. - - . 2-200". 1 200"-205". I 205"-210".210"-315". 215"-220". ~ 220"-238". I 5 34 ~ 26 , 23 , 6 3 20 30 ~ 19 1 7 1 1.049 188-220 18 12 12 39 I 14 - 1.069 200-225 I 32 I 18 10 24 , 9 4 0 0 1 0 : 3 0 1 2 5 1 40 Specific Boiling I 1.0748 195-224 1,0748 195-222 20 1.0650 210-238 1.0642 208-238 0 0 2 37 I 21 36 ________--___ ___ ~ - __ 9 j Normal 4 1 Straw colour Neutral Y 9 5 1 Kear1.y I 7 7 1 8 Y 7 I -_- Crystals in 15 minutes ;I ~ solid in 40 minutes J I No crystals in 5 hours ; } ~ solid in 18 hours solid in 15 minutes Solid almost Crystals in 4 minutes ; Solid on cooling I 4i V B G % 9 LI - .r( a --- None None 8 16 - colourless , colourless I 6 1 Nearly I Faintly acid I 8 Normal Solid on cooling - I -- ' --_ The author points out that none of the samples complied with the requirements of the United States Pharrnacopceia.For the estimation of the guaiacol, the following process was used : 5 C.C. of the creosote are mixed with 50 C.C. of a 20 per cent. alcoholic solution of potassium hydroxide, and the resulting crystalline compounds of guaiacol and cresol, which deposit in from ten to thirty minutes, are pressed between filter-paper until dry. The mass is then mixed with 5 C.C. of 10 per cent. sulpburic acid, and the mixture heated for a moment until the guaiacol and cresol rise to the surface. Water is then added until the oily layer sinks to the bottom, the aqueous layer decanted off, and 4 C.C. of concentrated ammonium hydroxide added. The guaiacol immediately forms a hard crystalline compound, and after some time a semi-crystalline mass results from the combination of the cresol.On treating the mixed compounds with benzene (benzin), only the ammonium compound of guaiacol remains undissolved, and this can be294 THE ANALYST. separated by decantation or filtration and washed. Finally, the residue is rendered acid with 10 per cent. sulphuric acid, and the guaiacol extracted with benzene, evaporated in a weighed basin, and weighed. In order to diEerentiate creosote from coal-tar phenols, one volume of the sample is shaken with a mixture of glycerin and water (3 : I), and left to separate. The diminution in the volume of creosote indicates approximately the amount of soluble impurities. The barium hydroxide test for ccerulignol and other high-boiling constituents gave a negative result with each of the six samples.In the author's opinion, the pharmacopoeia1 requirements of creosote should be based on the following points : Physical appearance, reaction, solubility, specific gravity (not lower than 1.080, at 15" C.), boiling-point (200" to 220" C.), reaction with a 20 per cent. solution of potassium hydroxide in absolute alcohol, and a test for neutral oils, C. A. M. The Characteristics of the Oil and Terpenes of Aralia Nudicaulis. W. C. A l p r s . (Amer. Jozcm. Pharnz., 1899, lxxi., 370-378.)-The rhizomes used by the author contained from 40 to 60 per cent. of water, and after being dried at 100" C., yielded on the average 5.53 per cent. of ash, of which nearly a quarter consisted of chlorides and sulphates of sodium and potassium. The volatile oil which was obtained from 50 kilos of the fresh roots by distillation with steam, and extraction of the essential oil from the distillate with chloroform, amounted to from 0.04 to 0.12 per cent.I t boiled at 260" to 270" C. under ordinary pressure, whilst the larger proportion of it distilled at 185" to 195" C. under st pressure of 88 mm. It was found to consist principally of a sesquiterpene, C15H2*, and an alcohol, C,,H,;OH(?), with a small quantity of a clear blue oil distilling at about 300" C., probably azulene C,,H,,O (I3.P. 302" C.). The sesquiterpene had a specific gravity of 0.9086 at 20" C., boiled at 270" C., and had a specific rotation of [.IL, = - 7 to - 8". I t formed oily addition-compounds with hydrochloric acid and bromine, and derivatives with nitrous acid. When dissolved in three parts of glacial acetic acid, and mixed with an equal amount of glacial acetic acid previously saturated with dry hydrochloric acid, it gave a rose colour, which gradually became purple, and aubsequently, in about ten minutes, sky-blue.The latter colour was permanent, and the liquid on distillation in vacuo yielded a blue liquid at about 140" C. Other colour-reactions were obtained by dissolving it in chloroform and adding sulphuric acid, which produced a purple-red coloration, and by adding sulphuric acid to its solution in acetic acid which gave a light wine-red colour. As these reactions and properties distinguish this sesquiterpene from isomeric compounds previously described, the author proposes for it the name araliene. C. A. M. - The Composition of Colophony.R. Henriques. (Chem. Rev. Fett. zc. Harx. Ind., 1899, vi., 10G-lll.)-The work described in this paper was undertaken with theTHE ANALYST. 295 object of determining whether the ester value of colophony was due to the presence of esters, and if not, what class of compounds were present. Dark samples of colophony were used in the experiments, since these have a greater ester value than lighter specimens, Cold saponification was employed, as it was found that with hot saponification there was evidently a more deep-seated change. The saponification value was determined by treating about 2 grammes of the substance with semi-normal alcoholic alkali, shaking for ten minutes until clear, and leaving the solution for about sixteen hours before titrating. Concordant results were obtained in this way, but the author considers that the results (about 3 units higher) obtained by leaving the liquid for forty hours, or by using normal alkali and leaving for 16 hours, may possibly be nearer the truth.Dieterich concluded that there were no esters in colophony, since he was unable to isolate alcoholic bodies from the products of saponification, but the contrary is asserted by R. Schick (Zeits. nizgew. Chem., 1899, 28) and others. The author reasons that, if the ester value be due to the decomposition of esters, a new quantity of acids must result on saponification, so that if after complete saponification the resin acids be liberated, washed, and their acid value determined and calculated on the original amount of substance taken, this second acid value will be greater than the first, provided that there has been a decomposition of esters.Otherwise the two values will be identical or nearly so. In practical experiments they were found to agree within about a unit, and hence the author concluded that there could have been no decomposition of esters. As considerably higher saponification values were obtained by using normal alkali and leaving the solution for forty hours, it was considered possible that the alkali acted on the acids, producing soluble acids of lower molecular weight. But since in one specimen the acid value was raised by saponification, but not raised in the case of another, the author regarded the question as open. AS it was possible that the constant ester value of colophony might be due to the presence of lactones, attempts were made to isolate such bodies, but they were not found at all, or at most in small amount (1 to 1.5 per cent.), the main constituents being resin acids and unsaponifiable matter (8 to 12 per cent.).Finally, the conclusion was arrived at that part of the resin acids themselves were probably of a lactonic character, containing both carboxyl groups and anhydride groups, and forming, in addition to the alkali salts obtained by direct titration, higher basic salts on exposure to the action of alkali in excess. In the author’s opinion there is nothing to justify the view of Dieterich that the slow saponification of colophony is due to the presence of acids so weak that they can only combine with alkali gradually and after a long time.As opposed to this view, he points out that the whole of the colophony acids are soluble i n a cold aqueous solution of sodium carbonate, and that if colophony be treated with moderately concentrated cold solution of sodium hydroxide, ether extracts little but unsaponifiable matter from the liquid. As there is a relationship between oxy-acids and lactone acids, and also a certain degree of proportion between the amount of the ester value and the insolubility of the296 THE ANALYST. acids in petroleum spirit, the author has applied Fahrion's method of estimating oxy- acids to the separation of the lactone acids (ANALYST, xxiii., 275). Fifty grammes of colophony (saponification value, 189.8 ; acid value, 158.7) were left overnight in contact with four or five times the volume of petroleum spirit.The supernatant liquid was decanted, and the residue boiled with four successive portions of petroleum spirit, dissolved in a hot solution of sodium hydroxide, cooled and filtered. The filtrate was acidified, and the resin acids filtered off, washed and dried. They were then pulverized, again boiled with petroleum spirit, dissolved in ether, the solution filtered, the solvent evaporated, and the acids dried at 100" C. I n two determinations with the same sample of colophony they amounted to 36 and 37.2 per in petroleum spirit were of a light yellow colour, kinds of colophony. Their acid value was 164.4, and By further treatment with petroleum spirit, this ester much darker, and on treatment with alksli yielded an cent.respectively. The resin acids soluble resembling that of the finer their ester value 4.0 to 4.8. value was reduced still more. The insoluble acids were intense reddish-brown solution. Their saponification value was about 196, their acid value 151.3 to 151.7, and their second acid value 144.8 to 147.6. Under the influence of hot saponification these values were greatly increased and not concordant, saponi- fication values of 274 and 324, and a second acid value of 317.8, being obtained. A further proof of the greater decomposition effected by hot saponification was shown by the fact that the recovered acids were no longer completely insoluble in petroleum spirit, and, unlike those from the cold saponification, gave an intense yellow colour on treatment with that solvent. As additional evidence that the constant ester value of the acids insoluble in petroleum spirit was due to the hydrolysis of the lactone groups, these acids were converted into calcium salts before and after saponification, and the amount of calcium in each determined.cent. after saponification, of the lactone groups is complete. given by the insoluble acids as readily as by the soluble acids. This was found to be 7.11 per cent. The author has not yet determined the exact point at which The well-known Storch's reaction with acetic anhydride and before and 9.30 per this decomposition sulphuric acid was I t was found that the light yellow varieties of colophony also contain traces of the lactone acids insoluble in petroleum spirit.In one experiment the author isolated 0.4 per cent. with the same characteristics as that obtained from the darker specimens. From these experiments the following conclusions were finally arrived at : 1. Colophony does not contain esters. 2. Acid anhydrides are not present in any quantity, but in the main unsaponifi- 3. These acids can be separated by means of petroleum spirit into normal soluble 4. The soluble acids have only an acid value, whilst the insoluble acids have a able matter and free resin acids. acids and insoluble acids having the character of lactone acids. high constant ester value in addition to their acid value. C. A. M.THE ANALYST. 297 Analysis of Indiarubbsr Articles. R. Henriques. (Zeds. angezo. ohem., 1899, 802.)-The author’s processes, which were originally described in the Chem. Zeit., 1892, xvi., 1595 ; 1893, xvii., 707 ; 1894, xviii., 411 and 905 (ANALYST, xviii.13, 227 ; xix. 111 ; xxii. 134), have stood the test of time ; but, having been altered in certain particulars, are worth recording anew, (1) Estimation of total Xulphzw a d Metals.-A 6 cm. hemispherical porcelain basin holding 30 C.C. is charged with 10 C.C. of purs strong nitric acid, covered with a watch-glass, and placed on a warm water-bath. 1 gramme of the sample (rasped or cut up) is weighed off, and a fragment dropped into the acid; as soon as red vapours appear, the rest is cautiously added at such speed that the reaction is continuous without becoming stormy-it can be controlled by removing the basin from the water-bath, or by heating it more strongly.When everything is dissolved, the cover-glass is wiped with a few pieces of paper which are dropped into the liquid, the whole is evaporated to a syrup, 20 C.C. more nitric acid are introduced, and the evaporation is repeated till most of the free acid is driven off. The mass is then stirred up with a mixture of 5 parts of sodium carbonate and 3 parts of potassium nitrate, covered with a layer of the same (using about 5 grammes altogether), warming, if necessary, the water-bath till all carbon dioxide is evolved. The basin is then covered with a similar vessel, concave side down, and heated with great care and very e lowly over a minute flame, which is gradually urged till the mass becomes black. The temperature is next raised until the salts fuse, the upper basin being removed towards the end of the operation.If successful, the cover only contains brown products of distillation which are free from sulphur ; but if spitting has occurred, some particles may adhere to the upper basin, and must be separately fused with the saline mixture. Finally, the melt is extracted with boiling water and filtered; the solution is acidified and silica and sulphuric acid determined; the insoluble matter is taken up with warm hydrochloric acid to separate silica from the metals, which are then severally estimated as usual. I n the case of rubber goods containing cinnabar a separate portion is taken, which, after decomposition with nitric acid, must be treated with water, and in the filtrate the heavy metals must be thrown down with sulphuretted hydrogen.(2) Estimation of 12ubber Substitutes in Vulcanised Products.-This process, though tedious, has not been found capable of simplification; it remains as outlined in the Chem. Zeit., 1892, 1625, and 1894, 411 (ANALYST, as cited above). A small improvement consists in removing the partially-dried caoutchouc mass from the filter, drying and weighing it separately, instead of employing a tared paper and weighing rubber and paper together. ( 3 ) Estimation of Unsaponi3able Oils in Vzdcanised Products.--Mineral oils, rosin oil, and parafin are to be found in many varieties of rubber goods; especially such as have been worked up a second time. After the mass has been treated with alkali, dried and weighed, the product is rubbed out in a basin and extracted with ether as long as the solvent becomes coloured; the solution is simply poured off, the residue is dried again and weighed, the loss being unsaponifiable oils.Ash and combined sulphur are determined on the product freed from oil.298 TEE ANALYST. (4) Estimation qf Rubber Siibstitutes. in Non-vulcaniscd Prodt&s.-Although suited for the examination of non-vulcanised '' patent " rubber plates, the regular process is not available for the treatment of sheets composed of soft rubber and substitutes ; the dificulty, however, is only due to physical causes, and the following modification avoids i t : 5 grammes of the sample are boiled under an inverted condenser with 25 C.C. of benzene for an hour, and allowed to rest over-night. 25 c.c, of normal alcoholic alkali are added, and the boiling is repeated for four hours. The solvents are removed on the water-bath, and the residue is rinsed into a large basin with hot water. I t is extracted with boiling water several times, the alkaline liquor being simply poured away; the rubber that remains is kneaded and boiled till no longer alkaline, and it is finally dried to constant weight at 100" C. ( 5 ) Estimntion of Unsaponi$able Oils in Non-vulcanised Products.-The ether process described in (3) obviously cannot be employed in the present instance; hot acetone is used 'similarly. But as the residual rubber is not easily brought into a condition fit for weighing, the extracts are run into a flask a-rld the acetone distilled off; the oils are taken up in ether, filtered into a tared beaker, and themselves dried and weighed. (6) Estimation of Ccwbon Diolride.-Chalk, magnesium carbonate, white-lead, and zinc carbonate are common loading materials ; but as the respective oxides are sometimes employed in their stead, it is often necessary to determine the carbon dioxide. Vulcanised goods are finely rasped and treated in Geissler's apparatus, charging the reaction-flask with dilute copper sulphate solution in place of water, as sulphides are frequently present. Prom non-vulcanised goods, the rubber must be partly or wholly removed by boiling with nitrobenzene, and the residue powdered and examined as before. Henriques remarks that he is unable to obtain uniform satisfactory results with Weberis solvent for indiarubber (nitrobenzene). Non-vulcanised materials, and such as are only lightly vulcanised and loaded, dissolve readily; but neither hard rubber goods, nor soft and heavily-loaded articles, can be completely separated therewith ; the liquids yielded by the latter class of wares, moreover, are exceedingly difficult to. filter. F. H. L.

ISSN:0003-2654    

DOI:10.1039/AN8992400288

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

298 THE ANALYST. INORGANIC ANALYSIS. Modification of Pierce’s Method for the Determination of Arsenic in Ores. J. F. Bennett, junr. (Journ. Amer. Chem. Xoc., vol. xxi. [5], pp. 431-435.)-The original method being rendered inaccurate by the solubility of silver arsenate in an excess of acid or alkali and in ammonium nitrate, by the extreme fineness of the precipitate and by the inadequacy of litmus as an indicator, the author proposes the following modification : One-half gramme of the finely-powdered substance is fused with 3 to 5 grammes of sodium carbonate and potassium nitrate in equal parts, about one-third being used as a cover. The filtrate, which contains the arsenic as alkali arsenate, is strongly acidified with acetic On cooling, the mass is extracted with boiling water and filtered.THE ANALYST.299 acid, then boiled to expel carbon dioxide, and, after cooling, treated with a few drops of alcoholic phenolphthalein and sufficient sodium hydroxide to give an alkaline reaction, the purple-red coloration produced by an excess of alkali being discharged by acetic acid. ,4 slight excess of neutral silver nitrate is then well stirred in, and the whole left to settle, away from direct sunlight ; the supernatant liquid is poured off through a filter, and the precipitate washed by decantation with cold water, thrown on the filter and washed thoroughly. The funnel being then filled with water and 20 C.C. of strong nitric acid, this liquid is run through the filter into the original beaker, the residue wasbed thoroughly with cold water, and the filtrate made up to about 100 C.C.and titrated with standard potassium thiocyanate (Volhard) ; or the silver is determined by scorifging the filter and precipitate, and cupelling, the first method being adopted when chlorides are present, c. s. Valuation of Gold Samples. W. Witter. (Chem. Zeit., 1899, xxiii., 522.)- A short time ago Bock stated that the ordinary process of gold cupellation was no longer delicate enough for modern requirements, and he propounded a new method of investigation based partly on electrolysis (C'he~n. Xeit., 1897, xxi., 973 ; 1898, xxii., 358). The present article describes experiments carried out at the request of the Hamburg Mint to ascertain how great is the difference between the results of met analysis and dry assay, whether assay is accurate enough to govern large financial transactions, whether Bock's process is better than cupellation, and whether it is always applicable. Starting with four carefully-analysed samples of gold - an unmelted electrolytic product, commercial electrolytic fine gold, washed gold as sent from Hong-Kong, and gold coinage (900")-using always the same quality acids, lead, and cupels, and the London Mint system of treating the rolls (Rose, ( ( Metallurgy of Gold," 1896, 445), the author found, as first enunciated by Rose, that the temperature of the muffle is a most important, though often overlooked, factor in obtaining correct figures by cupellation.Employing Heraeus's platinum- rhodium element with a Keiser and Schmidt galvanometer, he deduced the following as the proper working temperatures: Chemically pure gold, 960" C.; less fine gold, 950" to 960" C.; gold containing a very little platinum, 1000" to 1010" C.; 973" malleable gold containing silver and copper, 960" C.; coinage metal (900 parts Au, 100 parts Cu), not exceeding 920" or 930" C. ; 720" gold with silver and copper, below 900" C. The detailed figures show also that when an approximately pure gold, such as an electrolytic product, comes to be assayed, the result of the test cannot be checked on absolutely pure metal; because (presumably) of the platinum in the former, which demands a higher temperature. Therefore the temperature of cupellation must be determined; and when a good pyrometer is not at hand, a series of alloys with melting-points rising by 20" or 25" between 850" and 1050" C., should be provided as guides.Analyses of the rolls obtained from the four varieties of metal mentioned above proved them to contain from 99.8576 to 99.8786 per cent. of gold, while the cupels retained 0.0370 to 0.0891 per cent.; the difference between the weights of the rolls and the true gold in them ranged between 0.1226 and 0.1424 per cent. ; therefore the proportion of gold volatilised was between 0,0335 and300 THE ANALYST. 0*0890 per cent. These results fairly bear out Napier’s statement that, according to the composition of the material, the difference between the amount of gold in the sample and in the roll (as determined by analysis) varies between 0.12 and 0.14 per cent. I t is thus necessary to watch that the weight of foreign metals in the rolls shall equal the weight of gold volatilised; but that this is practically possible the author’s experiments demonstrate.I n short, if the temperature be kept at the proper point, the yield of the cupellation process will not differ from the theoretical by more than 0.2 part per 1000. Now, especially with high-grade samples, a wet analysis cannot safely be conducted by determining directly the amount of gold ; for, as Kriiss’s researches have shown (Liebig’s AnnuZen, 1887, ccxxxviii., 67), precipitation of pure gold chloride may lead to errors ranging between - 0.4 or - 1.4 part to +Om3 part per 1000. Thus, the foreign metals must be estimated, a process which requires at least four weeks, and quantities of 50 or 100 grammes for its successful operation. Very low quality gold cannot be assayed, and analysis becomes necessary; but such specimens are rarely met with at the present time.Gold is usually sold in parcels of 5 to 25 kilos., each of which is tested; therefore the sum in dispute, assuming the two tests to differ by the maximum amount (0.4 part per IOOO), is comparatively small; and owing to the greater rapidity of assay, the interest on this sum is less than when a wet analysis is insisted on. On the whole, if properly conducted, cupellation yields quite satisfactory results, and an analysis is seldom of practical value. In Bock’s process the sample of gold is melted with silver in a graphite crucible, the product rolled out, melted again, once more rolled, and then treated as usual with nitric acid of the specific gravities 1.2 and 1.3.The rolls are next electrolysed for ten minutes, washed, etc., and ignited. Bock omitted to specify the exact strength of the current; Witter finds as the maximum to avoid danger of disintegration, 1 ampere (ND,,,) calculated on the cathode, using 1 part of 1.2 nitric acid and 5 parts of water as the electrolyte. It seems better, however, to allow the current to pass for twenty or thirty minutes at a density of less than 1 ampere (0.05 to 1.0) in order that all silver, and all other metals that are remov- able, shall be dissolved. Nevertheless, the whole of the silver and other metals cannot always be removed, and it is sometimes necessary to repeat the process; on the contrary, losses may occur in the crucible and by disintegration during boiling or during electrolysis.As the result of a large number of trials, Bock’s method appears to give average errors of +O to +0*2 part per 1000. Bock’s process has the advantage of not needing so much previous experience to bring it to a successful issue, and of leaving cupellation available as a check; but it is not suited to all varieties of impure gold. Primarily intended for coinage metal, it can also be employed on any silver and copper alloys that are malleable; brittle alloys, by simple fusion with silver, still remain brittle, and so they cannot be beaten or rolled out ready for the electrolytic treatment. In laboratories where frequent analyses of a uniform malleable quality of gold have to be made, Bock’s process is to be recom- mended; but in places where the samples vary widely, a preliminary dry assay is indispensable, and it depends entirely upon circumstances whether the electrolytic method is applicable to control the results.F. H. L.THE ANALYST. 301 Determination of Gold, and its Separation from Platinum and Iridium. L. Vanino and I;. Seeman. (Ber., 1899, xxxii., 1968.)-When a solution of gold chloride is mixed with hydrogen peroxide and sodium (or potassium) hydroxide, the metal is completely thrown down in the cold within the space of a few minutes; whereas precipitation with ferrous sulphate or oxalic acid requires several hours. So delicate is the reaction that it will dekect 0.03 milligramme of gold in 10 C.C. of a liquid, the other tests beginning to fail between 0.09 and 0.06 milligramme per 10 C.C.A test with ferric chloride, hydrochloric acid, and a fragment of zinc, stated by its author to be capable of detecting 1 part of gold per 1,000,000 (Pharm. C. H., xxvii., 321), is equally sensitive with the present one, giving a reddish coloration in fifteen minutes with 0.03 milligramme per 10 c.c., but failing with half that amount. For quantitative purposes a dilute solution should be warmed after the metal has fallen, and after warming hydrochloric acid should be added to bring the precipitate into a state fit for easy filtration; the acid, however, must not be. introduced before warming. Platinum and iridium are not precipitated by alkaline hydrogen peroxide in the cold, so that they can be separated frorn gold by the above process; ruthenium is attacked, and is therefore not amenable to like treatment.Silver may be estimated similarly. F. H. L. Separation of Iron and Aluminium by Volatilising the Ferric Chloride. F. A. Gooch and F. S. Havens. (Zeits. anorg. Chem., 1899, xxi., 21.)-When ferric oxide is heated to 180" or 200" C. in a stream of dry hydrochloric acid gas, the bulk of the material (about 90 per cent,) is rapidly converted into chloride and volatilises ; the residue is almost black, insoluble in water, slightly soluble in cold (aqueous) hydrochloric acid, but fairly soluble in the hot acid, yielding a solution of ferric chloride. This dark substance, presumably an oxychloride, is only attacked by gaseous hydro- chloric acid at the above temperature quite slowly, producing finally a whitish residue composed essentially of ferrous chloride, which is scarcely capable of volatilisation at 500" C.This phenomenon of dissociation can be prevented, and completle volatilisaticln attained, either by first heating the oxide to 450" or 500" C., and then passing a rapid current of hydrochloric acid vapour, or by carrying out the process at 180" or 200" C. in an atmosphere of hydrochloric acid containing a little free chlorine-the latter method is distinctly to be preferred. Mixtures of ferric oxide with alumina (0.1 to 0.2 gramme of each) can thus, as the examples quoted show, be quantitatively separated at 200" by treatment with the two gases for from half-an- hour to one hour. F. H. L. Volumetric Estimation of Nickel and Zinc in German Silver and Similar Copper Alloys.J. Jedlicka. ( L i s t y chemickd, 1899, xxiii., 25 ; through Chem. Zeit. Rep., 1899, 256.) - One gramme of the finely-powdered alloy is dissolved in the minimum of nitric acid, and evaporated on the water-bath with a little sulphuric acid. The residue is diluted, neutralized, freed from iron with sodium succinate, the copper is reduced with sulphurous acid, thrown down with potassium thiocyanate, and the sulphurous acid driven off from the filtrate. The liquid, which302 TEE ANALYST. contains the nickel and zinc (it must not contain any ammonium salts), is heated to boiling in a large porcelain basin, inixed with sodium carbonate solution, and oxidized with sodium hypochlorite, keeping the whole faintiy alkaline, so that the nickel may be completely thrown down as peroxide.In order to make the precipitate filter easily, only the smallest necessary quantities of the reagents are added ; and to prevent it adhering to the vessel, the parts of the basin uncovered by the liquid are cooled with water before introducing the hypochlo7ite. The precipitate, consisting of nickel peroxide and basic $&-carbonate, is boiled and washed by decantation three times, and filtered through asbestos. I t and the asbestos are next rinsed into a beaker, and decom- posed by stirring and warming to 40" or 50" C. with the needful volume of semi- normal oxalic acid, which is partly oxidized and partly combines with the nickel and zinc. When the last dark-coloured particles of nickel peroxide have disappeared, the carbon dioxide is driven off by boiling, and the solution is titrated with alkali ; it is then diluted sufficiently, acidified with sulphuric acid, and titrated with per- rnanganate containing 10 or 15 grammes of the potassium salt, per litre.Small amounts of cobalt (0.3 to 0.5 per cent.) cause a trifling error, but the process only occupies two or three hours, and with care gives results within 0.1 or 0-2 per cent. of the truth. F. H. L. The Volumetric Estimation of Sulphur in Iron by means of Arsenious Acid. (Zeit. anal. Chem., 1899, xxxviii., 342-344.)-This method is based on the liberation ol sulphuretted hydrogen and its subsequent absorption by decinornial arsenious acid solution, 1 C.C. of which is equivalent to 0.002556 gramme of hydrogen sulphide, or 0.0024045 gramme of sulphur.In making an estimation of the sulphur in iron, steel, etc., the usual method of liberating the sulphur as hydrogen sulphide, and absorbing the gas by a reagent, is followed, Care must be taken, however, that the hydrochloric acid used to dissolve the metal is added as slowly as possible. After the requisite quantity of acid has been added, and the contents of the flask have begun to boil, the flame is so regu- lated that the boiling only just continues. In this way the distillation of too much hydrochloric acid is prevented. For the absorption, the author prefers the apparatus devised by E. Franke, but states that the well-known apparatus of Weigert and von Reis can also be used, though with the latter it is advisable to place an additional condensation bulb between the generating and absorption flasks. The latter is charged with 25 C.C.of a decinormal solution of arsenious acid and 50 C.C. of a cold-saturated solution of sodium bicarbonate. When the iron is completely dissolved the current of carbon dioxide is passed through the apparatus until the whole of the sulphur has been precipitated as arsenious sulphide, which takes place in about ten minutes. The liquid is then rendered acid by means of a few C.C. of hydrochloric acid, made up to 500 c.c., shaken and filtered. The residual arsenious acid is titrated in an aliquot part of the filtrate in the usual manner. The following are some of the results obtained by this method and by the hydrogen peroxide method : J.Thill.THE ANALYST. 303 Hydrogen Peroxide Method. Sulphur, per cent. Arsenious Acid Method. Sulphur, per cent. Thomas pig-iron . . 0.108 ... 0.105 1 , 9 , ... 0.081 ... 0.083 1 2 11 ... 0.095 ... 0.090 P ? 1 1 ... 0.148 . . I 0.148 C. A. M. .~ - -_ The Use of Potassium F errocyanide for Preparing Standard Ferric Solutions for Volumetric Purposes. K. Schroder. (C'hem. Zed., 1899, xxiii., 533,540, 557.)- The author finds that potassium ferrocyanide is one of the best substances for preparing an iron solution for volumetric work. I t has the advantage over iron filings and wire of being homogeneous, and over solutions (of Mohr's salt, etc.) of being unaffected by changes in temperature. I t caD be converted into a ferric salt quickly and with little trouble ; and the usual destruction or removal of superfluous oxidizing material is avoided.Its purity need only be examined once, determining the pro- portion of water and that of iron by a gravimetric process; for it keeps indefinitely in brown or black bottles. From the commercial article a pure product is obtained by rapid recrystalliza- tion from a boiling saturated solution, draining the crystals with the pump, drying them for twenty-four hours between paper, then digesting them with absolute alcohol, draining and drying for forty-eight hours as before. For use, 4 or 5 grammes are rinsed into a 500 C.C. flask of Jena glass, with 20 or 25 C.C. of sulphuric acid (specific gravity 1.84) ; the vessel is placed slantingly on a tripod, and is heated over a, bare flame which does not touch the flask, till, after a few agitations, solution is afhted.The flame is raised till the carbon monoxide is wholly driven off, then raised further until the liquid boils briskly (using a coil of platinum to prevent bumping). I t was found by the author that the iron by this treatment was campletely converted into the ferric state, the salt formed being, according to Fownes, ammonium- potassium-iron alum- (NI-I,),SO,+ K,SO,-t 2Fe,(SO,),. After thirty minutes it is cooled, 25 C.C. of water are introduced and mixed with the solution; 10 or 15 C.C. of 1.19 hydrochloric acid are next run in, and the whole is boiled for five or ten minutes. The liquid which contains all the iron in the ferric state is ready to be employed as a means of standardizing stannous chloride or (obviously) iodine, if an excess of tin be taken, The titration must not be carried out in flasks with a pronounced yellow tint, or the end-reaction will be difficult of observation. The figures quoted by the author respecting the composition of re- crystallized potassium ferrocyanide show a satisfactory agreement with the formula K,Fe(CN), + 3H,O.F. H. L. Valuation of Persulphates. G. H. Mondolfo. (Chem. Zed., 1899, xxiii., 699.) -This process depends on the reaction : M'SO, + KI = M'KSO, + I. Two or three grammes of the sample are dissolved in 100 C.C. of cold water, 10 C.C. of the liquid are mixed with an excess (0.25 to Q.5 gramme) of potassiumYY4 THE ANALYST. iodide, and warmed for ten minutes to 60” or 80” C.The liberated iodine is titrated with decinormal thiosulphate and starch, 1 C.C. of the reagept corresponding to 0.0114 gramme of NH,SO,, or Go 0.0135 gramme of KSO,. F. H. L. Estimation of Acids from the Volume of Hydrogen they evolve on Treat- ment with Metals. (Chem. Zed., 1899, xxiii., 624.)-The author has already described (Zeits. anal. Clzem, 1891, xxx., 175 ; 1892, xxxi., 392) a process of determining nitric acid by reducing it to ammonia with nascent hydrogen, and noting the deficit of gas liberated when an excess of iron and a known quantity of sulphuric acid are employed to generate the latter. It has been suggested that occlusion might interfere with the accuracy of the method ; further experiments have therefore been instituted which disprove this objection, and show that the process is available for the gas-volumetric estimation of inorganic and many organic acids.To generate the hydrogen, 2.5 grammes of “ferrum pulveratum” and 10 drops of a 5 per cent. solution of platinic chloride are used, but within reasonable limits the exact quantities are immaterial. The volume of gas is read off after a few minutes’ shaking, for although a little continues to be evolved for several hours, the reaction is practically completed at once. The strength of the acid may vary within wide limits, but it should not be too weak [apparently it should be about decinormal]. Owing to solubility and the presence of oxygen, the yield of hydrogen is always slightly below the theoretical: 20 c.c. of decinormal sulphuric acid evolve 22.05 C.C. instead of 22.34 C.C.As an example of the accuracy attainable, normal sulphuric acid was pre- pared by diluting strong acid according to the indications of the above process; 10 C.C. finally neutralized 28.65 C.C. of baryta-water, whereas 10 C.C. of normal acid standardized on sodium carbonate neutralized 28.70 c. c. Hydrochloric acid may be treated similarly, also phosphoric acid, but owing to the formation of ferric phosphate, the latter reaction is slower, and the same portion of iron cannot be used so often. Oxalic, acetic, and succinic acids give correct results ; lactic acid (possibly by reason of impurity) comes out too low ; tartaric and citric acids present certain difficulties, liberating too much gas. I(. Ulsch. Further details are promised.F. H. L. Tests for Boric Acid. V. Lenher and J. S. C. Wells. (Journ. Amer. Chem. Xoc., vol. xxi. [5], pp. 417-420.)-An improved method of performing the flame-test has been devised by the authors, the apparatus employed being a test-tube containing the substance and reagents, and closed by a cork fitted with a small glass tube drawn out to a fine jet. Heat being applied to the test-tube, and the alcoholic vapour ignited, the flame will show the presence of 0.1 per cent. of boron trioxide, the test thus being ten times as delicate as the ordinary flame-test. Copper and barium salts do not colour this flame. The authors determined the limits of sensitiveness of the other tests in use, with the following results: Boric ether flame (old method), 1.0 per cent. ; glycerin method, 0.1 per cent.; potassium fluoride and acid sulphate, 1.0 per cent turmeric c. s. paper, 0.01 per cent.THE ANALYST, 305 Valuation of Hydrogen Peroxide. A. Sonnie-Moret. (Re$. Pharm., 1899, [3], xi., 289 ; through Chem. Zeit. Rep., 1899, 224.)-Three or four C.C. of the solu- tion are brought into a nitrometer filled with mercury, 1 or 2 C.C. of sodium hydroxide solution are added, and 0-3 or 0.4 gramme of finely powdered manganese dioxide is introduced into the liquid through the mercury by means The volume of gas is then read off. of a glass tube. F. H. L. its Percentage by Paul Parey, The Valuation of Basic Slag (Thomas Meal) on the Basis of of Soluble Phosphoric Acid. P. Wagner. (Pamphlet published Berlin, 1899.)--So many changes have been made during the past few years in the treatment of Thomas slag, with the object of increasing the solubility of the phos- phoric acid, that its composition now differs essentially from that formerly produced.The proportion of easily-decomposable calcium silicate now present is much greater than was formerly the case, with the consequence that the combined action of this and the free lime present is sufficient to so reduce the acidity of the official (German) citrate Solution, as to affect its solvent action upon the phosphoric acid of the slag. The author has carried out a series of experiments with the view of determining the relative manurial values of the slags now on the market, and of so modifying the oficial method as to adapt it to suit the altered circumstances.He finds that a citrate solution containing 2 per cent. of free citric acid is preferable to the official solution containing only 1.4 per cent. For testing pure slags, a simple aqueous citric acid solution may be used, but the acidified citrate solution has this advantage, that it affords a means of distinguishing between pure slags and those mixed with ground Redonda or Belgian phosphates. Thus, a Belgian phosphate treated with a citrate solution containing 2 per cent. of free citric acid showed a solubility of only 8 per cent., whilst the same phosphate treated with a 2 per cent. aqueous citric acid solution showed a solubility of 30 per cent. The following are abridged directions of the process recommended by the author : I. Solutions : 1. A 10 per cent.citric acid stock solution containing 5 grammes of salicylic acid 2. The same diluted to a 2 per cent. strength. 3. Molybdate solution : 150 grammes of ammonium molybdate to be dissolved in 500 C.C. of water, 1 litre of nitric acid of 1.19 specific gravity, and 400 gramrnes of ammonium nitrate to be added, and the whole diluted with water to 2 litres. The solution to be allowed to stand for twenty-four hours at 35" C., and then filtered. 4. Magnesia mixture : 110 grammes of magnesium chloride and 140 grammes of ammonium chloride to be dissolved in 1,300 C.C. of water, and 700 C.C. of 8 per cent. ammonia added. The solution to be allowed to stand for several days, and then filtered. 5. Citrate-magnesia mixture: 200 grammes of citric acid to be dissolved in a 20 per cent.ammonia solution, and made up to a litre with the same solution. This solution to be then mixed with 1 litre of the magnesia mixture. 11. The determination is carried out as follows: 5 grammes of the Thomas per 10 litres.306 THE ANALYEST. meal are placed in a half-litre flask contairhg 5 C.C. of alcohol, and the flask filled to the mark with dilute (2 per cent.) citric acid solution, at a temperature of 17+" C. The flask is then closed with a caoutchouc stopper, and shaken for thirty minutes in a rotating apparatus making thirty to forty revolutions per minute. The liquid is then filtered. Fifty C.C. of the filtrate are placed in a beaker, 80 to 100 C.C. molyb date solution added, the mixture warmed to 60" to 70" C., and allowed to cool. I t is then filtered, the precipitate washed with 1 per cent.nitric acid solution, and dissolved in about 100 C.C. of 2 per cent. ammonia. Fifteen C.C. magnesia mixture are then added, the mixture allowed to stand for two hours, the precipitate filtered 08, washed with 2 per cent. ammonia solution, dried, ignited, and weighed. H. H. B. S. Determination of Oxygen in Water. L. Mutschler. (Zeit. -fiir Untersuch. der Nahr. und Genzi,ssmitteZ, ii., 481-484.>-By means of the apparatus shown in The bottle is the accompanying figure, the author adapts Mohr's method, for the determination of oxygen in water in situations where the accommodation of a properly-equipped laboratory is not available. The apparatus consists of a strong bottle of about 1 litre capacity with a wide neck, to which is fitted a double-bored caoutchouc stopper.The tubes 2 , 3 , and 4 are made of thin glass, so that they can be easily fractured by means of the glass or agate ball 1. They are filled with the reagents and sealed up. The tube 4 is for the sulphuric acid. I t is of 15 to 20 C.C. capacity, and is fixed through the central hole in the stopper, as shown in the figure. The tube 2, of 5 to 8 C.C. capacity, is for the soda solution, and the tube 3, of 25 to 30 C.C. capacity, for a known quantity of ferrous ammonium sulphate solution. Through the second hole in the stopper a narrow-bore glass tube is fixed, flush with the under surface of the stopper, and projecting about 2 cm. above the top. On the projecting part is fixed a piece of caoutchouc tubing, which can be closed by means of a small piece of glass rod, thus providing a vent.filled with the water to be tested, the tubes are inserted, the The determination is carried out ,as follows : stopper fixed in its place, and the vent-tube closed. The bottle is then carefully shaken so as to fracture and release the contents of the ferrous salt and soda tubes without breaking the sulphuric acid tube. The latter is left intact until after the return to the laboratory, when its contents are similarly discharged, The bottle is then allowed to stand for 10 to 15 minutes until the fluid clears, after which it is washed out with boiled water, and the unoxidized ferrous salt determined by titration. H. H. B. S. Action of a Hard Water on Certain Metals. J. L. Howe and J. L. Morrison. (Joum. Amsr. Chem. Xoc., vol. xxi. [5], pp. 422-425.)-The water examined was foundTHE ANALYST. 307 to corrode brass fittings; it contained per 100,000 parts: Lime, 7.30, magnesia, 4.065, carbon dioxide, 30.196, sulphur trioxide, 0.2127 parts, chlorine a trace. Strips of brass, zinc, copper, iron, lead, and aluminium were immersed in the water during four months, with and without access of air, and duplicate tests were made with distilled water. The results of the subsequent examination of the metal and water lead to the conclusion that waters of the above class, free from chlorine, attack zinc more readily than distilled water does, and dissolve out this metal from brass ; they should therefore not be conveyed through zinc-lined iron pipes. The hardness of this water does not prevent it dissolving lead, the action being more than half as great as that of distilled water when protected from the air. When air is excluded, the action on iron is relatively elight, and this water has no influence on aluminium or nickel, c. s.

ISSN:0003-2654    

DOI:10.1039/AN8992400298

出版商:RSC    

年代:1899

数据来源: RSC

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THE ANALYST. 307 APPARATUS. An Electrically-heated Drying Oven. T. W. Richards. (Anzer. Chem. JOZLT., 1899, xxii., 45.)-The general construction of this oven is shown by the annexed drawing. G is a frame composed of two parallel porcelain clamps, such as are used for securing electric wires, held together by n?eans of glass rods passing through the screw- holes, and with larger glass tubes encircling the rods to act as distance pieces. Round the porcelain sides of the frame is wound a coil of platinum wire to act as the resistance. F is a stationary fan made by cutting radial slits in a circle of sheet tin or platinum, bending the sectors through an angle of 45"; or it may be constructed of mica vanes and a platinum centre, etc. Its object is to force the current of hot air to ascend in spiral in order to produce a uniform temperature in all parts of the oven; this it does to within 2".The walls, D, consist of two beakers with their bottoms cut off, the annular space being packed with asbestos, etc. L! E The cover is either a clock-glass, a porcelain basin, or a tile, C is 8 porcelain tile, B layers of asbestos, A a wooden base. The quantity of wire on the resistance must obviously vary according to circumstances. Richards quotes for a 52-volt current, and prescribes 5 metres of No, 32 B. and S. [about No. 35h S.W.G. =0*008 inch, or 0.2 millimetre] platinum wire. This when heated has a resistance of about 25 ohms, requires, therefore, 2 amperes (which can safely be taken from a lighting circuit), and absorbs 100 watts-an amount of energy that is capable of heating an oven large enough for most analytical laboratories. If the current be obtained from 8-volt accumulators, from 5 to 15 amperes should be needed, according to the dimensions of the apparatus; in this case thin platinum foil would make the best resistance.Tho fixed resistance is adjusted to give the maximum temperature; lower heats are308 THE ANALYST. produced by including other resistances outside, or by increasing the amount of air admibted. An ordinary 16 candle-power glow-lamp fixed inside a paraffin-lamp chimney, the whole jacketed with a tin caD, forms an efficient makeshift which will hold a crucible ; it gives a temperature of 120" C. or 130" C. F. H. L. The Incandescent Llectric Lamp as a Source of Heat in Ether Extraction. C. G. Hopkins. (Journ. Amer. Chern. SOC., vol. xxi. [S], pp. 645-647.)-For heating a battery of twenty Soxhlet apparatus, the author employs five ordinary 110-volt thirty-two candle-power lamps placed in an air-bath of galvanized iron, 36 x 3 x 6 inches, lagged with asbestos to prevent radiation, the removable cover being perforated by twenty 2-inch holes in two rows. The lamps are set 7 inches apart, under the centres of the squares formed by every four holes, thus equalizing the heat, which is sufficient to distil about 60 drops per minute in each apparatus. The usual tempera- ture of the bath does not exceed 75" C., but since, when all the holes are covered, the heat may attain the ignition point of ether, it is advisable, for absolute security in case of breakage of any of the flasks, to immerse the lamp-bulbs in water. The economy of these lamps is high, about 96 per cent. of the electrical energy being converted into heat. c. 8.

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DOI:10.1039/AN8992400307

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年代:1899

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308 THE ANALYST. R E V I E W . A TREATISE ON PRACTICAI, CHEMISTRY AND QUALITATIVE ANALYSIS. By FRANK CLOWES, D.Sc., Emeritus Professor in the University College, Nottingham ; Chemical Adviser to the London County Council, etc. Seventh edition. London : Churchill, 1899. This work, which has now reached its seventh edition, is so well known to students and teachers of chemistry, that any special review of it is almost unneces- sary, and criticism is disarmed. I t has, in fact, become a standard work, and may be regarded as one of the leading English text-books of Qualitative Analysis, It has perhaps ever been a vexed question whether detailed directions to the student are on the whole better than a brief outline of the tests to be made by him, but the unqualified success of Dr. Clowes’s work may be taken as a strong argument in favour of the former view ; and always provided that the student; can be induced to read, there can be no doubt that a conscientibus study of this manual will insure a sound knowledge of the subject, while the time of the teacher will be largely saved. The tables of differences constitute a very special feature, and in this and the later editions there is scarcely any branch of the subject which has not been more or less fully handled, notably many organic substances of importance, and the reactions of the rare metals. There is perhaps only one regrettable omission-that of the theoretical explana- tions of analytical processes; these I venture to think might still find a place in a new edition. Dr. Clowes is not unconscious of this omission, and alludes to it in his preface, H. W. H.

ISSN:0003-2654    

DOI:10.1039/AN8992400308

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

THE ANALYST. DECEMBER, 1899. THE SALE OF FOOD AND DRUGS ACT OF 1899. [I62 & 63 VIC., CH. 61.1 ARRANGEMENT OF SECTIONS. Section 1. 2. 3. 4. 5. 6. 7. 8. 9. 10. 11. 12. 13. 14. 15. 16. 17. 18. 19. 20. 21. 22. 23. 24. Precautions against impartation of agricultural and other produce insufficiently Power for Local Government Board or Board of Agriculture to sample articles Power for Local Government Board or Board of Agriculture to act in default Power for Board of Agriculture to make regulations as to analysis of milk, Extension of Margarine Act, 1887, to margarine-cheese. Marking of margarine and margarine-cheese. Provisions as to manufacturers of and dealers in margarine and margarine- Restriction on amount of butter fat in margarine. Provision as to name and address of person selling milk or cream in a public Division of samples taken in course of delivery or transit.Provisions as to condensed, separated, or skimmed milk. Notice of mixtures. Amendment of 38 RT 39 Vic. c. 63, as to samples. Taking samples in course of delivery. Amendment of 38 & 39 Vic. c. 63, as to registered parcels. Obstruction of officer in discharge of his duties. Penalties for offences under the Sale of Food and Drugs Acts. Articles sold in tins or packets. Time for proceeding and regulation as to summons. Provisions as to me of warranty or invoice as defence, and proceedings against Duty of court to send articles for analysis. Provisions as to certificates of analysis. Transfer of powers from Secretary for Scotland to Local Government Board. Application to Ireland.marked. of food. of local authority. cream, butter, or cheese. cheese. place. the warrantor.310 THE ANALYST. Section 25. Interpretation of terms. 26. Definition of ‘‘ food.” 27. 28. Short title arid gorqmencement. Repeal of enactments in schedule. Schedule. CHAPTER 51. AN ACT TO AMEKE THE LAW RELATING TO THE SALE OF FOOD AND DRUGS. [August 9, 1899.1 BE it enacted by the Queen’s most Excellent Majesty, by and with the advice and consent of the Lords Spiritual and Temporal, and Commons, in this present Parliament assembled, and by the authority of the same, as follows : 1.-If there is imported into the United Kingdom any of the following articles, (a) Margarine or margarine-cheese, except in packages conspicuously marked (‘ Margarine ” or ( ( Margarine-cheese,” as the case may require ; or ( b ) Adulterated or impoverished butter (@her than margarine), or adulterated or impoverished milk or cream, except in packages or uans conspicuously marked with a name or desckiption indicating that the butter or milk or cream has been so treated; or (8) Condensed separated or skimmed milk, except in tins or other receptacles which bear a label whereon the words (‘ Machine-skimmed Milk ” , or ‘( Skimmed Milk,” as the case may require, are printed in large and legible type; or ( d ) Any adulterated or impoverished article of food to which Her MFjesty may by Order in Council direct that this section shall be applied, unless the same be imported in packages or receptacles conspicuously marked with a name or description indicating that the article has been so treated; the importer shall be liable, on summary conviction, for the first offence to a fine pot exceeding twenty pounds, for the second offence to a fine not exceeding fifty pounds, and for any subsequent offence .to a fine not exceeding one hundred pounds.(2) The word ‘‘ importer ” shall include any person who, whether as owner, consignor, or consignee, agent, or broker, is in possession of, or in anywise entitled to the custody or control of, the article ; prosecutions for offences under this section shall be undertaken by the Commissioners of Customs; and subject to the provisions of this Act this section shall have effect as if it were part of the Customs Consolida- tion Act, 1876. (3) The Commissioners of Customs shall, in accordance with directions given by the Treasury after consultation with the Board of Agriculture, take such samples of consignments of imported articles of food as may be necessary for the enforce- ment of the foregoing provisions of this section. (4) Where the Commissioners of Customs take a sample of any consignment- in pursuance of such directions, they shall divide it into not less than three parts, and namely :THE AXALPST.311 send one part to the importer and one part to the principal chemist of the Govern- ment laboratories, and retain one part. (5) In aay proceeding under this section the certificate of the principal chemist of the result of the analysis shall be sufficient’evidence of the facts therein stated, unless the defendant require that the person who made the analysis be called as a witness.(6) If, in any case, the Commissionars of Customs are of opinion that an offence against this section has been comruitted, they shall communicate to the Board of Agriculture for their information the name of the importer and such: other facts as they possess or may obtain as to the destination of the consignment. (7) For the purposes of this section an article of food shall be deemed to be adulterated or impoverished if it has been mixed with any other substance, or if any part of it has been abstracted so as in either case to affect injuriously its quality, substance, or nature. Provided that an article of food shall not be deemed to be adulterated by reason only of the addition of any preservative or colouring matter of such a nature and in such quantity as not to render the article injurious to health.2.-(1) The Local Government Board may, in relation to any matter appearing to that Board to affect the general interest of the consumer, and the Board of Agriculture may, in relation to any matter appearing to that Board to affect the general interests of agriculture in the United Kingdom, direct an officer of the Board to procure for analysis samples of any article of food, and thereupon the officer shall have all the powers of procuring samples conferred by the Sale of Food and Drugs Acts, and those Acts shall apply as if the officer were an officer authorized to procure samples under the Sale of Food and Drugs Act, 1875, except that-- (a) The officer procuring the sample shall divide the same into four parts, and shall deal with three of such parts in the manner directed by section fourteen of the Sale of Food and Drugs Act, 1875, as amended by this Act, and shall send the fourth part to the Board, and ( b ) The fee for analysis shall be payable to the analyst by the local authority of the place where the sample is procured.(2) The Board shall communicate the result of the analysis of any such sample to the local authority, and thereupon there shall be the like duty and power on the part of the local authority to cause proceedings to be taken as if the local authority had caused the analysis to be made. 3.-(1) I t shall be the duty of every local authority entrusted with the execution of the laws relating to the sale of food and drugs to appoint a public analyst, and put in force from time to time, as occasion may arise, the powers with which they are invested, so as to provide proper securities for the sale of food and drugs in a pure and genuine condition, and in particular to direct their officers to take samples for analysis.(2) If the Local Government Board or Board of Agriculture, after communication with a local authority, are of opinion that the local authority have failed to execute or enforce any of the provisions of the Sale of Food and Drugs Acts in relation to any asticle of food, and that their failure affects the general interest of the consumer or312 THE ANALYST. the general interests of agriculture in the United Kingdom, as the case may be, the Board concerned may, by order, empower an ofTicer of the Board to execute and enforce those provisions, or to procure the execution and enforcement thereof in relation to any article of food mentioned in the order. (3) The expenses incurred by the Board or their officer under any such order shall be treated as expenses incurred by the local authority in the execution of the said Acts, and shall be paid by the local authority to the Board on demand, and in default the Board may recover the amount of the expenses with costs from the local authority.(4) For the purposes of this section an order of the Board shall be conclusive in respect of any default, amount of expenses, or other matter therein stated or appearing. (5) L4ny public analyst appointed under the Sale of Food and Drugs Acts shall furnish such proof of competency as may from time to time be required by regulation framed by the Local Government Board.4.-(1) The Board of Agriculture may, after such inquiry as they deem necessary, make regulations for determining what deficiency in any of the normal constituents of genuine milk, cream, butter, or cheese, or what addition of extraneous matter or proportion of water, in any sample of milk (including condensed milk), cream, butter, or cheese, shall for the purposes of the Sale of Food and Drugs Acts raise a pre- sumption, until the contrary is proved, that the milk, cream, butter, or cheese is not genuine or is injurious to health, and an analyst shall have regard to such regulations in certifying the result of an analysis under those Acts.(2) Any regulations made under this section shall be notified in the London and Edinburgh Gazettes, and shall also be made known in such other nianner as the Board of Agriculture may direct. 6.-The provisions of the Margarine Act, 1887, as amended by this Act, shall extend to margarine-cheese, and shall apply accordingly, with the substitution of ‘‘ margarine-cheese ” and ( ( cheese ” for ‘( margarine ” and “ butter,” and provided that all margarine-cheese sold or dealt in otherwise than by retail shall either be inclosed in packages marked in accordance with the Margarine Act, 1887, as amended by this Act, or be itself conspicuously branded with the words ‘‘ margarine-cheese.’’ 6.-(I) Where under this Act or the Margarine Act, 1887, it is required that any package containing margarine or margarine-cheese shall be branded or marked, the brand or mark shall be on the package itself, and not solely on a label, ticket, or other thing attached thereto.(2) The letters required t o be printed on the paper wrapper in which margarine or margarine-cheese is sold shall be capital block letters not less than half an inch long and distinctly legible, and no other printed matter shall appear on the wrapper. (3) The words “ o r with” in section six of the Margarine Act, 1887, shall be repealed. 7.-(1) Every occupier of a manufactory of margarine or margarine-cheese, and every wholesale dealer in such substances, shall keep a register showing the quantity and destination of each consignment of such substances sent out from his manufactory or place of business, and this register shall be open to the inspection of any officer of the Board of Agriculture.THE ANALYST. 313 (2) Any officer of the Board of Agriculture shall have power to enter at dl reasonable times any manufactory of margarine or margarine-cheese, and to inspeut any process of manufacture tberein, and to take samples for analysis. (3) If any such occupier or dealer- (a) Faik to keep such a register, or ( b ) Refuses to produce the register when required to do so by an officer of the Board of Agriculture, or ( c ) Fails to keep the register posted up to date, or (d) Wilfully makes any entry in the register which is.false in any particular, or ( e ) Fraudulently omits to enter any particular which ought to be entered in the he shaIl be liable on summary conviction for the first offence to a fine not exceeding ten pounds, and for any subsequent offence to a fine not exceeding fifty pounds.(4) The proviaions of section nine of the Margarine Act, 1887, relating to regis- tration of manufactories shall extend to any premises wherein the business of a wholesale dealer in margarine or margarine-cheese is carried on. ( 5 ) The registration of a manufactory or other premises shall be forthwith notified by the local authority to the Board of Agriculture. 8. I t shall be unlawful to manufacture, sell, expose for sale, or import any margarine the fat of which contains more than ten per cent. of butter fat, and every person who manufactures, sells, exposes for sale, or imports any margarine which contains more than that percentage shall be guilty of an offence under the Margarine Act, 1887 ; and any defence which would be a defence under section seven of that Act shall be a defence under this section, and the provisions of the former section shall apply accordingly.Provided that nothing in this section shall apply to any margarine manufactured or imported in fulfilment of any contract made before the twentieth day of July one thousand eight hundred and ninety-nine. 9. Every person who, himself or by his servant, in any highway or place of public resort sells milk or cream from a vehicle or from a can or other receptacle shall have conspicuously inscribed on the vehicle or receptacle his name and address, and in default shall be liable on summary conviction to a fine not exceeding two pounds.10. I n the case of a sample taken of milk in course of delivery, or of margarine or margarine-cheese forwarded by a public conveyance, the person taking the sample shall forward by registered parcel or otherwise a portion of the sample marked, and sealed, or fastened up, to the consignor if his name and address appear on the can or package containing the article sampled. 11. Every tin or other receptacle containing condensed, separated, or skimmed milk must bear a label clearly visible to the purchaser on which the words ( ( Machine- skimmed Milk,” or “ Skimmed Milk,” as the case may require, are printed in large and legible type; and if any person sells or exposes or offers for sale condensed, separated, or skimmed milk in contravention of this section, he shall be liable on summary conviction to a fine not exceeding ten pounds.12. The label referred to section eight of the Sale of Food and Drugs Act, 1875, register ,3r4 THE ANALYST. shall not be deemed to be distinctly and legibly written or printed wftlrin the meaning of that section unless it is so written or printed that the notice of mixture given by the label is not obscured by other mattier on the label: Provided that nothing in this enactment shall hinder or affect the use of any registered trade mark, or of any label which has been continuously in use for at least seven years before the commencement of this Act ; but the Comptroller-General of Patents, Designs, and Trade Marks shall iiot register any trade mark purporting to describe a mixture unless it complies with the requirements of this enactment.13. In section fourteen of the Sale of Food and Drugs Act, 1875, the words ‘‘ offer to ” and the words ‘‘ proceed accordingly and shall ” shall -be repealed. 14. The provisions of section three and section four of the Sale of Food and Drugs Act Amendment Act, 1879 (relating to the taking of samples of milk in course of delivery), shall apply to every other article of food: Provided that no samples shall be taken under this section except upon the request or with the consent of the purchaser or consignee. 15. I n section sixteen of the Sale of Food and Drugs Act, 1875, the words ‘I registered parcel” shall be substituted for the words 16. Any person who wilfully obstructs or impedes any inspector or other officer in the course of his duties under the Sale of Food and Drugs Acts, or by any gratuity, bribe, promise, or other inducement prevents, or attempts to prevent, the due execution by such inspector or officer of his duty un&er those Acts, shall be liable, on summary conviction, for the first offence to a fine not exceeding twenty pounds, for the second offence to a fine not exceeding fifty pounds, and for any subsequent dence to a fine not exceeding one hundred pounds.17.-(1) Where, under any provision of the Sale of Food and Drugs Act, 1875, a person guilty of an offence is liable to a fine which may extend to twenty pounds as a maximum, he shall be liable for a second offence under the same provision to a fine not exceeding fifty pounds, and for any subsequent offence to a fine not exceeding one hundred pounds.(2) Where, under any provision of the Sale of Food and Drugs Acts, a person guilty of an offence is liable to a fine exceeding fifty pounds, and the offence, in the opinion of the court, was committed by the personal act, default, or cuIpable negligence of the person accused, that person shall be liable (if the court is of opinion that a fine will not meet the circumstances of the case) to imprisonment, with or without hard labour, for a period not exceeding three months. 18. Notwithstanding anything in section seventeen of the Sale of Food and Drugs Act, 1875, where any article of food or drug is exposed for sale in an unopened tin or packet duly labelled, no person shall be required to sell it except in the unopened tin or packet in which it is contained.10.-(1) When any article of food or drug has been purchased from any person for test purposes, any prosecution under the Sale of Food and Drugs Acts in respect of the Sale thereof, notwithstanding anything contained in section twenty of the Sale of Food and Drugs Ach, 1875, shall not be instituted after the expiration of twenty- eight days from the time of the purchase. (2) In any prosecution under the Sale of Food and Drugs Acts the summons registered letter.”THE ANALYST. 315 shall state perticulars.of the offence or offences alleged, and also the name of the prosecutor, and shall not be made returnable in less time than fourteen days from the day on which it is served, and there must be served therewith a copy of any analyst’s certificate obtained on behalf of the prosecutor.20.-(1) A warranty or invoice shall not be available as a defence to any pro- ceeding under the Sale of Food and Drugs Acts unless the defendant has, within seven days after service of the summons, sent to the purchaser a copy of such warranty or invoice with a written notice stating that he intends to rely on the warranty or invoice, and specifying the name and address of the person from whom he received it, and has also sent a like notice of his intention to such person. (2) The person by whom such warranty or invoice is alleged to have been given shall be entitled to appear at the hearing and to give evidence, and the court may, if it thinks fit, adjourn the hearing to enable him to do so.(3) A warranty or invoice given by a person resident outside the United Kingdom shall not be available as a defence to any proceeding under the Sale of Food and Drugs Acts, unless the defendant proves that he had taken reasonable steps to ascer- tain and did in fact believe in the accuracy of the statement contained in the warranty or invoice. (4) Where the defendant is a servant of the person who purchased the article under a warranty or invoice he shall, subject to the provisions of this section, be entitled to rely on section twenty-five of the Sale of Food and Drugs Act, 1875, and section seven of the Margarine Act, 1887, in the same way as his employer or master would have been entitled to do if he had been the defendant, provided that the servant further proves that he had no reason to believe that the article was otherwise than that demanded by the prosecutor. (5) Where the defendant in a prosecution under the Sale of Food and Drugs Acts has been discharged under the provisions of section twenty-five of the Sale of Food and Drugs Act, 1875, as amended by this Act, any proceedings under the Sale of Food and Drugs Acts for giving the warranty relied on by the defendant in such prosecution, may be taken as well before a court having jurisdiction in the place where the article of food or drug to which the warranty relates was purchased for analysis as before a court having jurisdiction in the place where the warranty was given.(6) Every person who, in respect of an article of food or drug sold by him as principal or agent, gives to the purchaser a false warranty in writing, shall be liable, on summary conviction, fw the first offence to a fine not exceeding twenty pounds, for the second offence to a fine not exceeding fifty pounds, and for any subsequent offence to a fine not exceeding one hundred pounds, unless he proves to the satis- faction of the court that when he gave the warranty he had reason to believe that the statements or descriptions contained therein were true.21. The justices or court referred to in section twenty-two of the Sale of Food and Drugs Act, 1875, shall on the-request of either party under that section cause an article of food or drug to be sent to the Commissioners of Inland Revenue for analysis, and may, if they think fit, do so without any such request.22.-(1) At the hearing of the information in any proceeding under the Sale of316 THE ANALYST. Food and Drugs Acts, the production by the defendant of a certificate of analysis by a public analyst in the form prescribed in section eighteen of the SaIe of Food and Drugs Act, 1875, shall be sufficient evidence of the facts therein stated, unless the prosecutor requires that the analyst be called as a witness. (2) A copy of every such certificate shall be sent to the prosecutor at least three clear days before the return day, and if it be not so sent the court may, if it thinks fit, adjourn the hearing on such terms as may seem proper. 23. This Act shall apply to Scotland with the substitution for ‘(the Local Government Board ” of ;‘ the Local Government Board for Scotland,” and all powers and duties vested in or imposed on the Secretary for Scotland in relation to the Sale of Food and Drugs Acts shall be transferred to, vested in, or imposed on the Local Government Board for Scotland.24. This Act shall apply to Ireland with the substitution for “ t h e Board OF Agriculture ” of the Department of Agriculture and Technical Instruction for Ireland,” and for (‘ the Local Government Board ” of ‘‘ the Loml Government Board for Ireland,” and for the London and Edinburgh Gazettes“ of 4 L the Dublin Gazette .” 25. In this Act, unless the context otherwise requires- The expression margarine - cheese ” means any substance, whether compound or otherwise, which is prepared in imitation of cheese, and which contains fat not derived from milk : The expression ‘( cheese ” means the substance usually known as cheese, containing no fat derived otherwise than from milk : The expression I ‘ local authority ” means any local authority authorized to appoint an analyst for the purposes of the Sale of Food and Drugs Acts, and the expression ‘( public analyst ” means an analyst so appointed : Other expressions have the same meaning as in the Sale of Food and Drugs Acts, and an offence under this Act shall be treated as an offence under those Acts.28. For the purposes of the Sale of Food and Drugs Acts the expression “food ” shall include every article used for food or drink by man, other than drugs or water, and any article which ordinarily enters into or is used in the composition or prepara- tion of human food ; and shall also include flavouring matters and condiments. 27. The enactments in the schedule to this Act are hereby repealed to the extenh mentioned in the third column of that schedule, 28.-(1) This Act may be cited as the Sale of Food and Drugs Act, 1899, and the Sale of Food and Drugs Act, 1875, and the Sale of Food and Drugs Act Amendment Act;, 1879, and the Margarine Act, 1887, and this Act may be cited collectively as the Sale of Food and Drugs Acts, 1875 to 1899, and are in this Act referred to as the Sale of Food and Drugs Acts. (2) This Act shall come into operation on the first day of January one thousand nine hundred.THE ANALYST. 42 & 43 Vic., c. 30. The Sale of Food and Drugs Act Amendment Act, 1879. 50 & 51 Vie., c. 29. The Margarine Act, 1887. I 317 words from “Every person who shallgive afalse warranty in writing ” to ‘‘ a penalty not exceeding twenty pounds.” Section ten. I n section six, the words ( < or with ” and the words ‘‘ not square. ’ ’ less than a, quarter of an inch SCHEDULE. ENACTMENTS REPEALED.

ISSN:0003-2654    

DOI:10.1039/AN8992400309

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

THE ANALYST. 317 PROCEEDINGS OF THE SOCIETY OF PUBLIC ANALYSTS. THE monthly meeting of the Society was held on Wednesday evening, November 1, in the Chemical Society’s Rooms, Burlington House, the President (Mr. W. W. Fisher, M.A.) occupying the chair. The minutes of the previous meeting were read and confirmed. Certificates of proposal for election to membership in favour of the following candidates were read for the second time : E. C. P. Barber, Chemist to the Anglo- Chilian Nitrate Railway Company, TOGO, Chili ; Frederick Davis, 51, Imperial Buildings, Ludgate Circus, London ; William Francis, Chief Analyst to the Con- densed Milk Company, of Ireland, Limerick ; Alfred Lucas, Analytical Chemist, Public Works Department (Geological Survey Branch), Cairo ; Edward Russell, B.Sc.(Lond.), F.I.C., Demonstrator of State Medicine, King’s College, London ; and F. L. Slocum, Ph.D., Pittsburgh, Pa., U.S.A. And in favour of the following Candidates for the first time: John Alfred Foster, A.I.C., Assistant Chemist, Her Majesty’s Dockyard, Portsmouth ; J. B. P. Harrison, A.I.C., Assistant Analyst to the Aylesbury Dairy Company, London; and D. Lloyd Howard, of Messrs. Howard and Sons, Stratford. Messrs. T. W. Glass, B.Sc., H. D. Hewitt, D. L. Thomas, and S. A. Woodhead, B.Sc., were elected members of the Society. The PRESIDENT, referring to the subject of Food and Drugs legislation, said318 THE ANALYST. thEtt since the Society’s last meeting the Sale of Food and Drugs Act, 1899, had received the Royal Assent, and would come into operation on January 1 next.It was satisfactory to note that the representations which the Society had made through its officers to the Government while the Bill was being considered had been favour- ably received, and for the most part adopted in the Act, which showed a considerable iniprovement when compared with the Bill as first proposed. VE‘ith regard to the clause which empowered the Board of Agriculture to direct officers to take samples under certain circumstances, there had arisen, from the manner in which the clause was worded in the Bill, an uneasy feeling that it might be interpreted as an attempt to centralize the work of analysis. The Society, however, had been assured by the President of the Board of Agriculture that there was no such intention, and it had been made perfectly clear that such samples would be submitted to the public analyst for the district in which they were taken, and treated as part of his ordinary local work.The central idea which the Society had expressed in regard to any further legislation-viz., thatl something in the nature of a standing departmental committee of reference should be established-was not given effect to in the form in which it was suggested, but a nucleus had been established by the new Act, and it remained to be seen in the future how far it would be developed and made useful. The wording of the section relating to the proportion of butter-fat to be permitted in margarine has been modified in accordance with a suggestion made by the Council, and a proposal which the draft Bill contained, involving an alteration of the form of certificate, had been abandoned, the form of certificate remaining as it was, The provision that any legal proceedings must be taken within twenty-eight days of the time of purchase would probably not inflict any great hardship on public analysts, given a reasonable amount of consideration on the part of those whose duty it was to purchase and submit samples.Various new articles had been brought within the Act, and one of the most useful alterations was the amendment of the definition of the word ‘‘ food,” the necessity for which had been impressed strongly upon the Government. Altogether, a distinct amount of progress had resulted from the recommendations which the Council had laid before the Government. It might also be mentioned that a committee had been recently appointed by the Local Government Board to inquire into the use of preservatives and colouring matters in food, and had invited the Society’s evidence on the subject, in the collection of which members had been asked to assist the Council by recording the results of their experience in a schedule which had been issued to them for the purpose. A paper was read by Dr. J. Lewkowitsch on ‘‘ The Meaning of the Acetyl Value in Eat Analysis.”

ISSN:0003-2654    

DOI:10.1039/AN8992400317

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

THE ANALYST 319 THE MEANING OF THE ACETYL VALUE IN FAT ANALYSIS. BY J. LEWKOWITSCH PH.D. (Read at the Meeting November 1 1899.) THE following lines are a continuation of a paper on ‘ I The Acetyl Value ” which I read before the Society of Chemical Industry (1897 503). Since that time the processes described have been very extensively used in my laboratory and their accuracy has been confirmed not only by different workers in my own laboratory, but also by other chemists. I t may however be useful to add some explanatory directions. The preparation of the acetyl product should be done as described previously. A number of experiments have shown that it is quite sufficient to wash the product; three times. Prolonged washing beyond the stated limit causes slight dissociation of the acetyl product ; of course this would lead to too low acetyl values.It should be noted that dissociation of the neutral acetyl product takes place in course of time and the splitting off of the acetyl group may be likened to the natural hydrolysis of the fats and oils. The outward sign of such hydrolysis having taken place is the more or less strong smell of acetic acid which the substance gives off on slight warming. On washing with water the latter acquires a diBtinct acid reaction. A measure of the amount of hydrolysis will be found in Column VIII. of Table No. I. The weight of the acetylated product required for the determination of the acetyl value should preferably be increased to about 5 grammes as for this quantity 1 C.C. of & KOH corresponds with about one unit in acetyl value.The distilled water used in determining the value by either the distillation or filtration process should be carefully freed from CO by previous boiling as other-wise serious errors may be made. Even the water used for generating steam in the distillation process should be brought to violent ebullition before the steam is passed into the distilling flask. This source of error may easily creep in in the case of very hard water. Check experiments with pure acetic acid will readily guide the operator if necessary. In order to facilitate the separation of the insoluble fatty acids in the filtration process it will be found useful to add a slight excess of mineral acid. Of course this amount must be measured accurately and deducted from the alkali required for determining the dissolved acids.A glance at the following tables will show that the two processes yield con-cordant results especially in the case of those oils which contain but small amounts of volatile fatty acid.* Those fats and oils however which are characterized by a large proportion of fatty acids standing on the border line between easily soluble and insoluble fatty acids - such as cocoanut and palm-nut oils - are more con-veniently examined by the distillation process; for in this case the fatty acids have a better chance of being well agitated with hot water. It is also necessary to collect at least 600 to 700 C.C. of the distillate (or filtrate as the case may be) in * Compare also my paper on the “Theory of Saponification,” Proc.Chem. Soc. 1899 190 TABLE I. ORIC:INAL OIL OR FAT. ACETYLATED OIL OR FAT. MIXED FATTY ACIDS. ACETYLATED MIXED FATTY ACIDS. 1. IT. III. 1V. \'I. VIr. VIII. xrr. XILI. XIV. XV. XVI. 1x. iaponifi-cation Value. X. 'otal Volatile Fatt: Acids per Gramm4 in terms of Mgrms KOH. X1. kqioiiifi cation Value. 'otal Volatile 1';ttt~ Acids per Grainmc 11 terms of Mgrms KOH. Apparent Acctyl 'slue after keepin, 1 year. Apparent Acctyl Value. Apparent Acetyl 'alue after keeping 1 ycar. Apparent Acetyl Value. True Acetyl Value. v.-rr. J;ymiiifi. cation Value. True Acctyl Value . YIIl.-X. Differ-cnce. m-1. fieliner Valuc. Hehiier Value. Uiffer-ence. YL-lX. 16.95 21.5 t2.5 8.9 8'2 0.0 8.0 2.5 -0'5 2'4 4% -2.5 1'5 17'5 Distill: tioii K'roccs Filtra-tion Process.Distilla-tion Process. Filtru-tion Process. DistilIa I tion Process. Filtra-tion Process. Distilla-tion PrOCCSS. Filtra-tion Process. 1)istilla-tion Process. Filtra-tion Process. Distilla- tion Process. 5'84 Filtra-tion Proccss. 6'9 Linseed . . . . . . . . . I 1 . . . . . . . . . I1 . . . . . . . . . I11 Maize . . . . . . . . . . . . I , . . . . . . . . . . . I1 Curcas . . . . . . . . . . . . . . Castor . . . . . . . . . . . . T: , . . . . . . . . . . . . I1 , . . . . . . . . . . . . I11 . . . . . . . . . . . . I V CoCa . . . . . . . . . . . . . . Olive . . . . . . . . . . . . I , . . . .. . . . . . . . I1 Horse's foot . . . . . . . . . . . Animal oil . . . . . . . . . . . Fish (containing coast cod oil etc.) Japan fish . . . . . . . . . . . 7 , 2.9 0'8 2.53 0.0 0-0 0'0 2.15 2-54 44-08 14.06 3'73 9'22 1'78 1.50 2.60 3'60 0'80 2.95 6.28 0.99 2.0 0.1 2.34 1.07 10'05 5.6 i 6.6 ! ' 6.7 4.22 2.40 7'24 1-3 4.8 1.4 0'58 21.09 21.07 20.89 19-55 11.4 14% 22.2 19.89 42.74 42.29 20'9 21-9 26'7 26.59 26.4 28'2 30'4 I 40.3 149.4 41.4 32.0 12'8 208.5 210.0 205'6 201.5 200.9 311.2 310.3 312.1 304'1 192'9 203.1 214-7 214-0 221.0 200'2 192-7 189'1 194.3 213'3 216.5 214.7 200'2 213.0 204.5 3 1'3.4 203% 202.4 204-5 207'8 200.5 199'6 236'0 237'1 240'4 249'5 253.9; 248.3 252'1 25'3% 259'8I 361.7 262'8 267'1 265'9 231.8 233.0 210.6 6.85 7'03 8-75 7-Sl 7'5 150.5 149'9 17'2 12'78 (13.16 112.96 1 22.04 41-88 13.3 16.47 7.9 4 75 1060 11.95 24.76 12.5 15.8 19.8 7'7 17-8 6.47 2-86 27'3 31.2 9'3 i 27'3 1 6-63 9'52 9'4 6'1 3-3 40.68 1 40.85 21.46 19-0 24.9 29'3 28.05 43'19 1.43-59 ) 23.2 28.8 32.2 34.5 38'7 39'85 48'48 1 49'29 f 45'23 47'2 39'4 200 6'92 8'25 8.21 t 7.9 149-6 149'4 146-7 146.9 16% 13'48 13'62 14-40 22'38 13'5 16-84 8'9 11-20 11-88 25'1 21.1 21.9 11.7 2 0 3 18.8 8.9 2-71 33.1 15.59 1 t 15.54 6.64 -i ;:g 1 10'4 F-1 [ g:;; } 53'55 23.7 41.0 Ji 3'98 5'81 150.05 149'65 146.7 14% 10.64 9'44 111.48 32.66 11.77 15-18 5'8 1.15 10.1 8'97 15.65 14% 18.0 7.6 15% 6.61 17-95 86-55 2.65 11.34 4.24 2'37 8'6 4-35 2'72 19.82 32-66 1-91 7'6 9.7 7.1 8.36 0.87 2.3 6.9 5-5 7'91 12'3 9'45 1.91 5.8 8-55 7-2 I 17'06 142.7 15-96 6-68 40'95 17-38 141.4 15'93 3.43 8'72 20'85 40.75 96'2 95.5 95.7 95.2 94.5 93'5 95'7 94.5 94'0 89'8 94.7 94.79 92-99 89'3 88.9 92.3 85.0 82.0 85'5 92.6 193.2 183'3 179.0 178.4 189'3 186'2 186'45 184-4 161.0 192.55 194.3 198-8 197'2 192.6 214.9 195'7 197'0 196.2 215.0 210'3 242'4 242.7 242% 244.08 236'5 256-1 255'6 256.9 258.7 256'9 257.9 225'9 225'4 205'2 127.9 125'1 14.5 10'9 6.5 2.7 11'9 14.2 7.3 27.; 8'8 10'8 4.3 21.55 30'1 7'1 11.25 5.7 8.02 3.3 3.75 6.1 5'0 8'4 8.0 5'9 7'6 5.4 Seal .. . . . . . . . . . Cod liverikept some yearsiii bottle I Cod liver fresh . . . . . . I1 Skate liver . . . . . . . . . . . Shark liver . . . . . . . . . . Cot ton-seed . . . . . . . . . I . . . . . . . . . I1 , . . . . . . . . . I11 . . . . . . . . . IV . . . . . . . . . v 11 3 199.45 401.2 400.7 103.2 153'9 851.0 l54.5 59'8 59'2 66'0 60'0 60'4 69'6 17-1 17'5 316'4 222'2 315'7 !12'8 t03.26 162.85 159'2 154.5 ,67.8 61.7 65.5 62.4 65'0 67.1 18% 35'0 !19 '4 99.99 99'6 99's 14'5 17'9 20'88 14.27 14.03 8.8 3'45 6'53 18.0 14-31 12.3 10'0 18'08 6'4 15.7 20'03 7'8 22.5 13'8 24-9 14.6 6'7 3'2 7.55 17.6 13'70 18'34 16-7 1.0 2.1 6'0 1.7 20'38 30O'o 31.3 .. . . . . . . . VI . . . . . . . . . VII . VIII contain. 23.8% &ee fatty acid: Sawarri . . . . . . . . . . . Cacao butter . . . . . . . . . . . Japan WELX . . . . . . . . . I , . . . . . . . . . I1 Lard . . . . . . . . . . . . . . Bone fat coiit.42*6% free fatty acids Beef marrow . . . . . . . . . . . . Tallow South American . . . . . . , home melt . . . . . . I . . . . . . 11. . . . . . . 111. , Premier Jus .. . . . . . . t 3, I 7 , Crotoii . . . . . . . . . . . I. 11. P&n nut,'cont&ing &68% free fatt Palm nut,' condiining'&~%'iitto 11. acids I 4.6 12.12 6.7 9'3 21.8 10'7 20'93 7 *8 5'8 13'4 8.0 2.19 5'6 0' 7 -2.97 5.55 4.9 0.0 16-7 9 . . . . . . . . . . . . , 3 . . . . . . . . . . . . 4 . . . . . . . . . . . . Cocoanut con. Y9,Y free fatty -acids , I , 3*9;! , .* ,, " 3 . . . . . . . . . . . . 4 . . . . . . . . . . . . 9% 10.6 3 . . . . . . . . . . . . 4 . . . . . . . . . . . . Butter fat . . . . . . . . . I. acids . . . . . . I{ : contairiing margarine . , containing 0'56xfreefatt 3 . . . . . . . . . 111. . . . . . . . . . IV. June. 3 August. .I Septeiuber. c e p g e 310 320 THE ANALYST.order to obtain the total amount of volatile acids; but even at best it is a somewhat tedious operation to drive off all the fatty acids of cocoanut and palm-nut oils. I now give in table No. I. a number of determinations made with various fats and oils. I n Column V. are registered the acetyl values as obtained by examining the acetylated products by the two processes described in my first paper. These values I have termed ‘ I Apparent Acetyl Values.” Owing to the presence of volatile fatty acids notably in the case of croton oil palm-nut oil cocoanut oil and butter-fat, the apparent acetyl values would be found too high; it is therefore necessary in order to arrive at the true acetyl value to-determine the amount of volatile fatty acids in the fat or oil before scetylation and to deduct their amount from the apparent acetyl value.The former values are given in Column II. under the heading, “ Total Volatile Fatty Acids per gramme in terms of mgrms. KOH.” They have been determined mostly by the distillation process in some cases by the filtration process as well in order to check the results. It is obvious in the case of the four last-mentioned fats that these values cannot be neglected. But even in the remaining cases they are not always negligible and they even vary for one and the same fat, showing as they do the state of freshness of the samples (compare below). Taking cotton-seed oil as an instance sample No. I. representing an indifferently refined oil contains a notable amount of volatile fatty acids when compared with sample VII., the volatile fatty acids of which are almost negligible.(In passing I may remark how erroneous it would be to draw conclusions from one sample of an oil only.) The difference between the apparent acetyl value and the total volatile fatty acids is given in Column VI. under the heading “ True Acetyl Value.” I have explained in my first paper (Jour. Xoc. Chem. Iud. 1897 504) why the difference of the saponi-fication values of the original and the acetylated fats and oils should not be taken as the true acetyl value; and the same stricture might apply to the differences registered in Column VI. However as the total volatile fatty acids in the case of castor oil are nil and in all other cases with the exception of the last four oils, very small and again as in the last cases the acetyl values are not very high no appreciable error is being committed.As regards the difference of saponification values registered in Column VII. in the case of castor oil which consists almost exclusively of glycerides of hydroxyacids, the incommensurability of the values of the original and acetylated oil becomes very pronounced and therefore it is no longer permissible to look in this case to the difference as a guide. Yet in almost all other cases enumerated in the following tables this difference may be used as an approximate check of the determination of the acetyl value-in fact on comparing the values in Columns VI. and VII. the agreement will be found satisfactory with the exception of course of castor oil as has been explained above.The agreement is satisfactory because the fats examined contained only small quantities of free fatty acids which give rise to the formation of anhydrides (cf. (‘ Proceedings Chemical Society,” 1890 ; 71 92) and therefore might have interfered with the reliability of the check. I n natural fats which have not reached a very advanced state of decomposition (or hydrolysis)-and here we are only concerned with such-the amount of free fatty acids is as a rule small. Hence this question need not be pursued any further THE ANALYST 381 The acetyl value has been classed as a constant ;'one would therefore expect the true acetyl value to be constant. The table reveals the fact that this is not always the case the deviations being much greater than the experimental error would warrant.Before discussing the question whether the acetyl value is a constant or must be regarded as a variable like the acid value of fats and oils it will be advisable to inquire as to the substances or classes of substances which the acetyl value measures. From the fact that castor oil known to consist mostly of glycerides of hydroxylated fatty acids-hydroxyolejc or ricinoleic acid -possesses the highest acetyl value viz., about 150 whilst the pure triglyceride of ricinoleic acid has the theoretical acetyl value of 159.1 it would appear that the acetyl value is a measure of hydroxylated fatty acids; indeed originally the acetyl value was proposed to measure them and has hitherto been regarded a measure thereof. Alcohols in a fat or oil would of course also show an acetyl value ; in this case the value is identical with the saponification value of the acetates.The amount of cholesterol and phytosterol in a fat or fatty oil rarely exceeds 1 per cent. hence the presence of these will hardIy affect the acetyl value. I n fact as an easy calculation will show the influence they exercise on the value will be found to be within the limits of the experimental errors of the method. This will be different in the case of waxes which contain notable amounts of free alcohols. I n order to arrive at definite figures I have determined the acetyl values of 8 number of waxes (see Table No. 11.). TABLE No. 11. Kind of Wax. ~-Liqu-Z xaxes : Sperm oil Northern . . . , Southern . .. > ? > ? ? best Arctic sperni I. 9 ) > 11. Solid waxes : Carrinuba wax . . . . . . Beeswax . . . . . . . . . Wool wax _ . Spermaceti . . Wool-wax alcohols . . . ORIQINAL WAX. I. --Saponifi-cation Value. 127.9 132.6 125 ' 2 133.7 1332 79.68 93.5 122.7 0.0 11. Total Volatile Fatty Acid8 per Gramme, in terms of Milli-gi-ammes KOR. -2'41 1-36 1 '48 1.29 1 -40 2-26 2'16 9 -30 1.97 2-2 ACETPLATED WAX. 111. -Saponification Value. -132'6- 133.3 139.1-1 40.3 130'9 137'5 116.0 107'35 128.8 139 '5-140.4 142.8-143*8 I\'. Hehner Value. -99-94 (39.94 100.0 100'2 99 *99 93 '4 100'2 98% 102.0 1 7 . - --Apparent Acetyl Value. 7'-\ Ijis tills.tion Process -. 8.95 8-56 7 -63 8.00 6.16 57'6 17'4 33.7 4'7 141.2 Filtra: tion Process. -_ 6 -85 7-08 5.83 7.28 4-88 57.4 31-5 4.5 V1. ' VII. , True Uiffer-Acetyl ' ence, Value. ' 111.-I. 4'49 6.43 5-25 6.35 4.12 55-24 1 5 2 4 23.3 2.63 5 '05 7 -1 5 *7 6 -25 4.3 36-32 13.85 I '1 143.8 140.3 143'3 Speaking broadly we find the same general outlines as in Table No. I. Whilst it is certain that in the case of carnauba wax bedswax and wool wax the true acetyl values indicate the presence of free alcohols further research must show whether the same can be said of the other waxes enumerated in the table. The last column shows that also in the case of waxes the difference of the saponification values of the origina 322 THE ANALYST.and the acetylated substances may be taken as a rough check of the correctness of the direct determination of the true acetyl value with the exception of carnauba wax which on account of the high proportion of free alcohols it is known to contain, affords a very good analogy to castor oil. TABLE No. 111. ORIGINAL OIL. 1 AC~TYLATED OIL. - _ _ - . - - - ____- ~-IX. x. - -vIxI Differ-x 5 5 ;*n;;. \ -6'4 9'47 11.1 10.72 12.6 9'46 15'8 17'4 1 19'1 4.18 6.23 9.6 11.25 17.1 111. ~ IV. I v. VI. I- ~ - - -I. i XI. VXI. -Appar-ent Acetyl Value. -_ 12-5 18.9 22 5 25'5 32-6 7.7 14.2 22.9 30.0 35.0 3.3 18.8 3.0 14'2 18'2 23-9 22.3 VIII. Total 7olatile ~ $ ~ ~ e .'Oxidized Saponi-:ramme Acids I fica-tsms Per ' tion Milli- Cent. I Value. Specific Gravity. zgtAfi 1 Value. I True Acetyl Value. 11.7 15-22 1 9 5 17'2 31 *7 7 -6 11-32 20.46 25 '4 30.84 2-72 ner ralue. _-36'2 34.4 34'6 33'2 32'1 95.7 94'8 92.9 91'9 91.4 92'6 99'9 98.5 99.4 97'8 97.5 rammes 1 KOH. -!-_I-0-8 205% ___ Linseed oil . . Linseed oil blown two hours a t 120" C. . Linseed oil 1,lowii four 1.2 ~ 200.9 0.9334 189.8 1-68 3'0 8.3 0.9 0 *1 2'88 2'44 4-60 4'16 0.58 0.95 2.9 3.6 4 *3 203.9 208.2 211.8 200.2 203.9 212.0 215'2 218'4 199.6 211.6 203.7 211.1 217.3 323.1 227.5 207'4 199.7 208'2 211'6 316.0 1.7 5.03 7 *1 0 51 0.87 0.94 1 *28 0.70 0'62 0.6 3.5 A.191.3 192*4 192.7 194-3 194.9 196.1 196% hours a t 120" C. . . . 0'9403 hours a t 120" C. I 0'9446 hours a t 120" C. 0-9460 Linseed oil blown six Linseed oil blown ten Cotton-seed oil . .:; 1 Cotton-seed oil blown, two hours a t 120" C. 0.9262 Cotton-seed oil blown four hours a t 120" C. I 0'9291 Cotton-seed oil blown six hours a t 120" C. 0-9350 Cotton-seed oil blown ' 13'97 16.96 1-49 19.1 21 -6 9.3 6.2 11 -3 15'0 14.1 ten hours a t 120" C. Premier jus . . Premier j u s blon-n four . . . Oleic acid . . Oleic acid blown two hours a t 120" C. . . . Oleic acid blown four hours a t 120" C. . Oleic acid blown six hours a t 120" 0.. . Oleic acid blown ten hours a t 120" C. . . . hours at 120" C. 1.9346 203.3 2-05 1'13 11.3 I 6.21 14% I 8-03 I I I 204.9 206.0 208.3 21 3 '4 1.9098 1.9121 39123 3.9238 19 *6 19'4 10.78 10.67 2-9 6-0 I 8-9 1 24.95 16-06 I 26.45 Blown rape oil com-mercial . Blown cotton-seed oii, commercial . . 62'04 53.14 65.6 48.54 3'9714 205.6 29'22 j 26.7 j 0'9522 Acid value 168 213.7 188.5 186.1 199.2 Boiled oil commercinl, I. Boiled oil commercial, 11. Drying oil preparedwith ozone I. Drying oil prepared with ozone 11. 25% 24'0 18'0 16-9 13.2 18.7 1.6 6.5 1.1 4.63 91.5 92.8 9-29 14-57 11.06 71.6 13'5 136-8 ~. 3.2 2.15 4-2 ' 3.85 26'5 20'1 Oxidized acids from so-lidified linseed oil 1 100.THE ANALYST 323 ’ The blown oils give high stcetyl values and it therefore appeared desirable to examine them as well. Table No. 111. gives the results of the examination of a number of blown oils prepared both on a commercial scale and in the laboratory ; to these are added some boiled oils as also blown oleic acid. Column IV; gives the apparent acetyl values; by deducting from them the amount of volatile fatty acids in the original oils stated in Column II. we obtain the true acetyl values registered in Column VII. I t has been widely assumed that the blown oils and also boiled oils contain hydroxyacids. Some years ago Fahrion proposed a method for their quanti-tative determination based on the insolubility of these acids in petroleum ether.I have however shown* that this method is valueless in the case of castor oil fatty acids and mixtures thereof with non-hydroxylated fatty acids ; I have therefore proposed for these insoluble acids the term ‘‘ oxidized acids ” pending further inquiry into their nature. The acetyl values given in Column VIII. Table No. III. further substantiate my objections ; for if we were to assume for these hypothetical hydroxy-acids the molecular weight of 300-which is in fact the molecular weight of hydroxy-stearic acid C,,H,,(OH)O,-it would be possible to calculate their amount. The calculation has been carried out by multiplying the true acetyl values by 0-55. The result is tabulated in Column IX. At the same time the oxidized fatty acids have been determined quantitatively by Fahrion’s method.They are set down in Column IV. With the exception of the commercial blown oils these numbers greatly deviate from those given in Column IX. although they run parallel to them, as one would naturally expect. I t is also remarkable that the difference of the saponification values (given in Column X.) which we have hitherto been able to use as a check no longer performs the same duty. I n order to gain some further insight into this question I have examined the oxidized fatty acids of solid oxidized linseed oil carefully freed from fatty acids soluble in petroleum spirit. The acetyl value of these acids was found to be 130, which on multiplication by 0.55 gives 71.6 per cent. of oxidized acids whereas theory would postulate 100 per cent.These oxidized acids possessed the acid value 168, and the saponification value 199. We must therefore assume the presence of lactonic substances a measure of their amount being furnished by the difference 199-168 = 31. I t might be thought for a moment that the acetyl test would permit a distinc-tion to be made between hydroxylated acids and lactones; but it must not be forgotten that true lactones cannot according to our present views assimilate acetic acid. Indeed Geiteli has shown that stearo-lactone does not react with acetyl chloride. In the case of commercial blown oils the true acetyl value approximately agrees with the proportion of oxidized acids ; hence we may safely conclude that the acetyl value is a measure of the oxidized acids. But in all the other cases given in Table No.111. we find that the calculated oxidized acids (compare Column IX.) are very much higher than those found direct. What then are the substances which lead to the high acetyl values? Are they hydroxylated acids which are soluble in petroleum spirit in contradistinction to + “Chernical Analysis of Oils Fats Waxes,” etc. Edit. I. p. 157 Edit. IT. p. 204. t Jour. Prakt. Chemie 1888 [37] 84 324 THE ANALYST. the oxidized acids? We can hardly assume that they are polymerized fatty acids, such as we can obtain from castor oil; for we know that polymerization tends to reduce the capacity for assimilating acetyl groups. It is impossible in the present state of our knowledge to pronounce a definite opinion. One naturally looks round for analogies.Thus pyromeconic acid to which the somewhat doubtful CH*O* CO CH-CO-dH, is ascribed yields on boiling with acetyl chloride acetylpyrorneconk formula C,H,(C,H,O)O,. formula, acid of the I may further point out that I have shown some years ago* that the mixed fatty acids from sawarri fat yielded an acetyl value of 14 whereas the fat itself has the acetyl value 6.6 (compare Tabla I.). I was able to show that these fatty acids contain lactonic substances. But as the fatty acids were experimented upon the evidence is not quite conclusive for reasons given below. Finally I may state that I found in the crystals obtained by the action of concentrated sulphuric acid on oleic acid and subsequent dilution with water a neutral substance whose saponifi-cation value on boiling with alcoholic potash agreed fairly well with the number stearo-lactone would demand Yet with acetic anhydride it yielded a product having an acetyl value and saponification value fairly corresponding with the numbers required for hydroxystearic acid.I am investigating all these points and in the meantime without committing myself to any definite opinion propose to describe them as “ unknown acids.” Their presence is indicated by the acetyl values set out in Table No. 111. Further research will also be required to determine the oxidized acids in the presence of true hydroxylated acids and 6 L unknown acids.” An investigation with this object in view is being carried on. The separation of hydroxylated acids from the oxidized acids is possible by means of the different solubilities of their salts.So far then it appears that an acetyl value indicates the presence of the following classes of substances : ( a ) Hydroxyacids. ( b ) Free alcohols. (c) Oxidized fatty acids. (d) ‘‘ Uuknown acids.” If fats contain mono- and di-glycerides the presence of these would cause the fat to exhibit an acetyl value. And if the moisture of the atmosphere is capable of hydrolysing triglycerides then it is not only possible but indeed very rikely that natural fats and oils which are not perfectly fresh will contain mono- and di-glycerides. I have shown in another paper,t in agreement with Geitel’s researches, that mono- and di-glycerides do occur in partially hydrolysed triglycerides. Here it would only be necessary to examine the question whether fats and oils that have undergone natwnl hydrolysis exhibit notable acetyl values due to this cause.The Compare also Proc. Chem. * Jour. SOC. Chem Ind. 1890 842. t ‘ The Theory of Saponification,” Joitr Xoc. Chem. Iml, 1898 1107. SOC. 1899 190 THE ANALYST. 325 numbers given in Table I. supply an answer to some extent. Besides I have examined several highly decomposed fats and oils containing a considerable propor-tion of free fatty acids. The latter were removed in the usual way and the remain-ing neutral fats examined. The results are set out in Table No IV. They were expected to contain lower glycerides. TABLE No. IV. Neutral Fat of Oil prepared from : ~ Saponifi- ' I cation I :zy 1 Value. - - ~ !758.794.34 ._ _ ~ - -Maize oil containing 30 per cent. free fatty acids . 1 ~ 188.8 94.37 Cocoanut oil coiitaining 3-9 per cent. free fatty acids (a) Soluble in alcohol . . . . . . . . . . . . 262.3 81.78 ' 253.8 86.5 1 * * ' 1 I 253.5 85.8 j . . . . . . . . . (b) Insoluble in alcohol I Cocoanut oil containing 1 3 2 5 per cent. free Catty acids ~ 259.8 82.58 . . . . . . * ' * c I 259.7 81-83 1 (a) Soluble in alcohol ( b ) Insoluble in alcohol . . . . . . . . . . . . . Palm oil containing 31.3 per cent. free fatty acids (a) Soluble in alcohol ( b ) Insolubl2 in alcohol ( a ) Soluble in alcohol . . . . . . . . . . . . (a) Insoluble in alcohol . . . . . . . . . . . . . . . . . . . . . . . . . { i . - * t . . . . . . . . . Palm oil containing 23.8 per cent. free fatty acids 251.9 86.8 189'7 187.8 194.1 193.4 194.1 197.9 186-0 195.7 196'2 196'9 93.05 I 89.96 f 93-22 93-66 93.80 92 $5 87 '4 94-28 f i 93.59 1 Palm oil containing 9.67 per cent.free fatty acids ' 196.5 92'7 1 93'37 j ( n ) Soluble in alcohol . . . . . . . . . . . 1 189.5 89.2 197'0 194.62 1 ( b ) Insoluble in alcohol . . . . . . . . . . . . i ~ 195.9 I 1 196.3 94'34 - ~ - - -~ - -~ _ _ AceTY LA1 ED PRODUCT. 111. I I\'. Y. I Sapoiiifi- Differ. Value. ~ cation ~ ence. I Value. 1 IV.-I. I-,-29'4 ' 210'3 I 21'6 29'2 ' 211'9 18'48 210% 23-61 209.9 23 -1 16.7 13.6 5.4 203.8 7-4 ___._ The samples of maize oil given in Table No. I. have a very much lower acetyl value than the neutral oil prepared from the rancid maize oil and both the acetyl value and saponification value of the acetylated oil seem to speak in favour of the presence of lower glycerides.Two samples of cocoanut oil containing 3.9 per cent. and 13.25 per cent. free fatty acids calculated as oleic acid respectively, were also freed from the fatty acids and the neutral oils presumably containing lower glycerides were treated with alcohol in the hope of resolving them into two fractions which might show differences in saponification and Hehner values as mono-and di-glycerides being more readily soluble in alcohol than triglycerides would pass into the alcoholic solution to a greater extent. The results given in the table do not speak against the presence of lower glycerides. Since however the triglycerides of the lower fatty acids occurring in cocoanut oil are also to' some extent soluble in alcohol too much weight must not be attached to the cocoanut oil experiment.N 326 THE ANALYST. such complication arises in the case of palm oil. Three samples of palm oil contain-ing 31.3 per cent. 23.8 per cent. and 9-67 per cent. respectively were treated in a similar fashion. These certainly point to the presence of lower glycerides. Unfortunately there was not enough of the portions soluble in alcohol left to determine the acetyl values. I give the results in Table No. IV. A more complete series of experiments will be taken in hand shortly. The presence of mono- and di-glycerides in natural fats would thus appear to deprive the acetyl value of its rank as a constant.The uncertainty caused thereby can be eliminated by saponifying the fats and determining the acetyl value of the fatty acids. One would naturally conclude that if the acetyl value of the original fat was due to mono- and di-glycerides the fatty acids would have a considerably lower acetyl value ; if not the acetyl value of the fatty acids should be approximately the same as that of the original fats. I have therefore determined the acetyl values of some mixed fatty acids prepared from fats whose acetyl values were known. The results can be gathered from Table No. I. In the following table No. V. I place side by side the acetyl values of the fats and their mixed fatty acids : TABLE No. V. Acetyl Value of 1. Cotton-seed oil . 2. 9 9 9 . 3. $ 7 3 . 4.Tallow . . 5. Palm-nut oil . 6. 7 . 8. C.ocoanut oil . 9. $ 7 9 . a * 10. . 11. ? 12. BuiLer-fat . 13. I . 14. Sawarri-fat . Fat or Oil. I. . I. 15-8 . 11. 11.7 . 111. 18.0 . 4.55 . r. 9.7 . 11. 7.1 . 111. 8.36 . I. 6-9 . 11. 5.5 . 111. 7 91 . IV. 9.45 . I. 5-8 . 11. 8.55 . 6.61 Insoluble Fatty Acids. 11. 17.9 14.1 21.5 3.3 13.4 8.0 2 *19 5% 0.7 - 2-97 - 0.9 0.0 16-7 14.03 Difference. I. -11. - 2.1 - 2.4 - 3.5 + 1.25 - 3.7 - 0.9 + 6-17' + 1.3 + 4.8 + 10.88 + 10.35 - 8-15 - 7.42 + 5.8 At first sight it appears that they prove nothing for Nos. 7 9 10 11 and 12 would seem to speak in favour of the presence of lower glycerides in the original fat whilst in Nos. 3 5 13 and 14 we notice a considerable increase in the case of the fatty acids.Finally Nos. 1 2 4 6 8 would not prove anything for the difference falls within the limit of experimental error. To explain the apparently capricious results one appears to be driven to the assumption that in Nos. 7 9 10 11 12 the original oils and fats contained lower glycerides whereas in the cases of Nos. 2 3 5 , 13,14 the fatty acids have become oxidized in the process of preparation thus leading to acetyl values as explained above THE ANALYST. 327 Cotton-seed . Curcas . . - It will be remembered that this very contingency was one of the remons whicb induced me to determine the acetyl values in the fats and oils themselves in preference to- the fatty acids. If there is any truth in the above-made assumption and if we further adopt the view supported by the best evidence that rancidity is due to the oxidation of the fatty acids setting in subsequently to the natural hydrolysis of triglycerides by the moisture of the atmosphere it does not appear improbable that the acetyl number might furnish a measure of the rancidity.The latter must not be considered as coterminous with acidity for whilst the acidity is only a measure of the hydro-lysis of the triglycerides the acetyl value would not only indicate the dissociation of the triglycerides but over and above that the amount of oxidation which has caused the fats to exhibit those properties which we comprise under the term " rancidity." In order to put this reasoning to the test a number of fats should be examined both in the fresh state and after exposure to the atmosphere.Only such fats aad oils can be chosen as can be considered practically pure triglycerides ie. such as hitve been freed from vegetable and animal tissue-in short of organic substances the contact with which causes triglycerides to undergo a rapid decomposition marked by the occurrence of a high proportion of fatty acids. Therefore such vegetable oils as commercial palm oil or unrefined seed oils or olive oil expressed from the fermented pulp would not be suitable for our purpose inasmuch as the presence of putrescible or fermentable matter or ferments themselves (lipases) induces hydrolysis. Nor would unrefined animal fats lend themselves to such an investigaticn ; nor even butter which contains legitimately organic non-fatty substances whereas butt=-fat would be more appropriate.After they had been tested in the fresh state they were exposed for some little time to the atmosphere. The numbers thus obtained are collated in Table No. VI. The differences given in Hitherto I have been able to examine a few fats only, TABLE No. VI. 193'2 Fresh. After Exposz6rc. -ORIGINAL OIL OR FAT. ACETYLATED OIL OR FAT. 1 v. -m r b % x 95.7 95'5 94.75 v. VI. _- -__I- I-' 1'15 6.1 1 4-55 3-3 I 2.72 VII. H U H H al 2 B s -125'1 2 '7 4.5 )RIGINAL OIL ACETYLATED OIL OR FAT. OR FAT. 7111. e s s G $ 9 g 4 m -193'0 194'2 180'2 192.7 193.1 loo-0 199.8 IX. x. -2 -1 1 '5 1 '8 8.7 0-49 2 '9 2 -3 201-E 200-4 304'6 199.7 210.7 206.2 XI.XII. - -____ -94.0 I 8.3 5 .O 93.2 14.5 93.6 112 10'1 9.4i 146.6 19'15 4.8 12-7 8-2 -.- I XIII. XIV. 1 xv. ! THE ANALYST, Column XV. show that the exposed or rancid fats possess higher acetyl numbers than the fats in the fresh state. I n the case of cacao butter and curcas oil a t least, the increase in the acetyl value cannot be attributed to the presence of lower glycerides. Yet the number of experiments made is too small to be conclusive evidence in favour of the opinion that the acetyl value might be a better indication of rancidity than the doubtful colour reactions proposed recently. There is all .the more reason to consider this an open question as the results of the examination of the palm-nut and cocoanut oils made at different periods (cf.Table No. I.) are some-what conflicting. The view that rancid fats contain hydroxyacids has frequently been put forward, and was apparently supported by the high acetyl values given by several chemists for rancid tallow butter-fat etc. Since however those acetyl values referred to the fatty acids and moreover as they were determined by a method which I have shown to lead to very unreliable results they cannot be quoted as favouring my opinion. Recently Gripper” has determined the acetyl values of a number of old rape oils by my method but the results do not show any regularity a fact which can only be explained by the assumption that hydrolysis as well as rancidity have each and severally contributed their quota to make up the acetyl value obtained.I expect that examination of a larger number of fats and oils concurrently with that of their mixed fatty acids will throw some light on this subject, We have thus seen that to the four classes of substances enumerated above, under a b c d we must add - ( e ) mono- and di-glycerides (J’) rancid fats. I n the case of most rancid fats it will be difficult to discriminate between classes e and f, more elaborate methods of analysis being required than we possess at present. Should they be found then we shall be in a position to discriminate by analytical methods between acid and rancid fats and dispense with organoleptic methods. I t will be clear that a value which is a measure of so many different classes of substances as the acetyl value is cannot be considered a constant but must be rather looked upon as a variable until we are in a position to differentiate by analytical methods between hydroxyacids oxidized and L( unknown acids,” and to allocate to each of these substances the respective quota which in their totality build up the acetyl value.Experiments have been taken in hand to elucidate these points ; at present we must unfortunately resign ourselves to pronounce a non Ziquet. The experiments detailed in the paper have been carried out by my assistants, Messrs. E. J. Read and C. D. Robertshaw. I wish to acknowledge here my indebtedness to them and especially to Mr. Robertshaw who has also prepared lantern-slides of the tables given.DISCUSSION. The PRESIDENT having invited discussion, Mr. HEHNER said that the author’s work in differentiating between the various reasons which caused a fatty body to have an acetyl number was very important. The total acetyl value measuring 8s it did the hydroxyl whether it be the hydroxyl * Jownal Boc. Chem. Ind. 1899 p. 342 THE ANALYST. 329 in an alcohoI or in an acid was in his opinion but rarely of such value from a, practical point of view as to repay the trouble of determining it castor oil and blown oils being the most noteworthy exceptions. But from the differentiation of the various hydroxyl groups useful information would probably result. Some of the author’s figures seemed to indicate that not only the unsaturated acids in a fat might spontaneously oxidize but that oxidation might also take place in the Eaturated acids since a fat like cocoanut oil for instance which contained very little oleic acid had a moderately high acetyl value.I t seemed to him a matter of great importance to ascertain if possible whether the unsaturated oil acids of the constitution of which we were almost entirely ignorant contained doubly or perhaps trebly linked carbon atoms. The difference in the properties of highly unsaturated oils might possibly be explained by different linking such as he has suggested. Dr. Lewkowitsch had plainly shown that the so-called oxy-acids of Fahrion consistedof at least two classes of substances one of which consisted clearly of hydroxylated bodies whilst the others were not hydroxylated. Mr.ARCHBUTT said that he had compared the acetlyl values respectively determined by the original method of Benedikt and by Dr. Lewkowitsch’s process, but without finding the labour involved by the latter (owing to the necessity of having to separately estimate and deduct the potash required to neutralize soluble fatty acids) commensurate from a practical point of view with the information obtained and he had not become convinced that the original process did not answer all practical purposes in the technical analysis of oils for the detection of adultera-tion. In castor oil the acetgl values obtained by both methods were practically identical but in samples of blown East India rape oil blown Ravison oil and blown cotton-seed oil considerably higher figures were obtained by the new method (unless the soluble fatty acids were allowed for) as shown by the following figures : Description of Oil.I Acetyl Vnlne of the I n -soluble Fatty Acids by Benedikt’s Process. - ~ _ _ _ _ I I Castor oil . . . . . I 149.5 56.8 Castor oil (another sample) . . . Blown East India rape oil . . . Blown Ravison oil . . . . j 150.8 I I . I I 53 -7 I Blown cotton-seed oil . . 69.6 I Acetyl Value of the Gly-cerides by Lewkowitsch’s Method without allowing for the Soluble Fatty Acids present. . 150.2 ~ 150.7 80.9 79.7 98-3 - ~~ -~ - - __ ~ If the anhydrides formed in Benedikt’s process were not hydrolysed again on boiling with water one would expect the results to be variable but practically constant results were obtained by Benedikt’s process on the blown oils referred to.Therefore, if it were required to use the acetyl value for differentiating between castor oil and blown oils or for detecting adulteration of the former with the latter a practically useful result would be obtained more easily by Benedikt’s process. In washing the acetylated glycerides obtained from blown oils there was a considerable tendency to emulsification on boiling with water whereas there was not tbe slightest difficulty in boiling and thoroughly washing out the excess of acetic acid from the acetylated fatt 330 TEE ANALYST. acids. From a scientific point of view the new process was no doubt the more perfect one but from the purely practical point of view of the analyst it seemed that the original process supplied all that was needed.Dr. LEWKOWITSCH in reply said he thought he might claim that his investigation was not wanting from the practical point of view. I n processes connected with the resolution of partly converted fatty acids and fats-such as the products of sulphuric acid saponification-or in the case of castor oil and turkey-red oils the acetyl value would be found to be of material assistance and in fact sometimes the only means of unravelling the mysteries in which such matters were often enshrouded. He agreed that it was not at present possible to differentiate between the different classes of substances indicated by the acetyl value but it was first of all necessary to ascertain what the acetyl actually indicated. Continental literature stated it to indicate the presence of hydroxylated fatty acids or oxy-acids but acetyl values would be obtained in fats like cocoanut oil and considerable confusion resulted from such values being reported as indicating the presence of hydroxylated fatty acids.With regard to the ‘‘ unknown ” acids what he meant and understood was shown in Column IX. of Table 111. Multiplying the true acetyl values by 0.55 values were obtained which were higher than the so-called oxidized fatty acids. The question might be asked Were not such substances merely hydroxylated fatty acids which were soluble in petroleum spirit? If they were the matter was finished but there was no evidence to support this. I n what particular way the oxygen was combined he did not think it was possible at present to say. If in a true hydroxylated acid the hydroxyl group were split off forming water with the hydrogen of the COOH group, there would result a true lactone which should not absorb acetic acid Stearo-lactone had been isolated and was stated not to react but he had found another substance to which the same formula seemed to apply but which gave high acetyl values. As a kind of analogy he had mentioned pyromeconic acid which did not contain a hydroxyl group but which yielded a well-defined acetylated product. There was a difference between the saturated and the unsaturated fatty acids as regards oxidation -between for instance stearic acid and oleic acid I n the case of stearic acid, hydroxylated acids were not obtained by blowing. I n the case of oleic acid the so-called oxidized fatty acids insoluble in petroleum spirit were practically very small in quantity while those calculated from Column VIII. were much higher. The difference unquestionably pointed to the formation of some other bodies which were able to absorb acetic acid and these whatever they were had been termed pro-visionally ‘‘ unknown ’’ acids. Most of the so-called acetyl values that were being passed into literature were merely values due to the oxidation or rancidity of the fats, having no quantitative meaning whatever as regards the original fats. In reply t o Mr. Archbutt he had been able to prove substantially that in Benedikt’s process the fatty acids were really converted into their anhydrides when boiled with acetic anhydride and that such anhydrides were not completely hydrolysed by boiling with water. I n the case of blown rape oil the so-called oxidized fatty acids did agree with those calculated from the acetyl value which led to the conclusion that this class of substances was amongst other things indicated by the acetyl value

ISSN:0003-2654    

DOI:10.1039/AN8992400319

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

THE ANALYST 331 ABSTRACTS OF PAPERS PUBLISHED IN OTHER JOURNALS. FOODS AND DRUGS ANALYSIS. Assay of Preparations containing Pilocarpine. H. A. D. Jowett. (The WeZcome Chemical Reseaych Laboratories Report No. 6 1899 1-7.)-The mixture of amorphous bases obtained from jaborandi or its preparations by any of the usual methods is dissolved in a small quantity of a saturated alcoholic solution of pilo-carpine nitrate the solution slightly acidified by means of a strong alcoholic solution of nitric acid (freshly prepared) and after the addition of a crystal of. pilocarpine nitrate left for two hours to crystallize. The cryatals are filtered off washed with the saturated solution of pilocarpine nitrate with the aid of a filter-pump dried and weighed. In most cases the author states that the crystalline deposit may be assumed to be pilocarpine nitrate but in very accurate estimations the melting-point and specific rotation of the substance should be determined.Assuming that pilocarpine is the only impurity and that Petit and PoIonowsky's constants for the nitrate of that base are correct the percentage of pilocarpine may be calculated from the specific rotation of the mixed nitrates by the formula p = - 100 (2- 38.5), 43 7 in which p represents the required percentage and x the specific rotation of the mixture. If the melting-point exceed 174" C. the substance may be rcgarded as pure pilo-carpine nitrate ; and if between 167" and 174" C. as containing from 80 to 90 per cent. of that salt. If the melting-point is lower than 167" C.the substance should be recrystallized from a small quantity of hot absolute alcohol and the deposit weighed and examined as above. The author shows that pure pilocarpine nitrate obtained from the small.leaved variety of jaborandi (Maradzam jnborandi) has the same physical characters as that obtained from the true jaborandi viz. melting-point 178" C. ; [ u ] ~ + 82.9" ; and solubility in water 1 in 6.4 at 20" C. A specimen of pure pilocarpine hydrochloride prepared in the usual way from the nitrate and purified by repeated crystallization melted at 204"-205" C. aud had a specific rotation of [a],,= +91*74". In examining these salts for medicinal purposes the following characteristics and tests are recommended as indicating a sufficient degree of purity : Pilocarpine Nitrate.-Wbite distinct crystals unaltered on exposure to the air.Soluble in 6 to 7 parts of water at ordinary temperatures in 146 parts of cold 95 per cent. alcohol fairly soluble in boiling alcohol nearly insoluble in ether or chloro-form. Specific rotation in aqueous solution +81" to 83". No residue on ignition. Gives no precipitate on adding to its concentrated aqueous solution ammonium hydroxide or a solution of sodium or potassium hydroxide. Melting-point 176" to 178" C. Gives the characteristic tests for nitrates 332 . -THE ANALYST. Pilocarpine Hydrochloride.-White arysbls which deliquesee in moist air. Soluble in less than its weight of water and in 10 pwts of absolute alcohol; almost insoluble in ether or chloroform. After being dried at 100" C. it melts at 200" to 204" C. No residue on ignition. On adding ammonium hydroxide to its concentrated aqueous solution there is no precipitate while potassium or sodium hydroxide only precipitates a few oily drops, which soon redkaolve and it gives the tests for chlorides. Specific rotation in aqueous solution +90" to 92". C. A. M

ISSN:0003-2654    

DOI:10.1039/AN8992400331

出版商:RSC    

年代:1899

数据来源: RSC

摘要:

332 . -THE ANALYST, ORGANIC ANALYSIS. Chlorine Compounds in Cotton Oil, and its Behaviour with the Pbloro- glucinol and Vanillin Test. (Chem. Zeit., 1899, xxiii., 769, 802.) -The fact that cotton oil gives a red colour with the author's phloroglucinol and vanillin test (ANALYST, 1898, xxiii., 244) has hitherto been explained, in accordance with Dupont's definite assertions, by the statement that the material contains an organic compound of sulphur. After examining four samples of cotton oil, however, obtained from Merck of Darmstadt, from Kahlbaum of Berlin, and commercially from France, Raikow finds that it is absolutely free from sulphur, and that the red colour is due to an ingredient containing chlorine. If a little cotton oil is burnt in the tubular torch already described (Zoc.cit.), and the flame is brought inside a beaker charged with a few drops of potassium hydroxide solution, which is held horizon- tally and slowly rotated so that its internal surface is wetted all over, the liquid will finally give the reactions of hydrochloric acid, but not those of sulphuric acid. Similarly, a repetition of Dupont's experiments (extraction of the oil with steam) has yielded distillates quite free from sulphuric acid. The chlorine compound in the original cotton oil is perfectly insoluble in water and alcohol, is not affected by treat- ment with steam at 100" C., but is slightly volatile in highly superheated steam; whether it can be entirely removed from the oil in this manner remains to be seen. Of the oils which give no colour with phloroglucinol and vanillin (ut sz~p.), olive and walnut contair, neither sulphur nor chlorine; of those which do give a red colonr, colza and rape contain sulphur but no chlorine.According to Benedikt. the presence of chlorine in fats is due to carelessness in carrying out a bleaching process, but Kilgore has stated that American cotton oil is bleached without the use of halogen. The chlorine must therefore be a natural constituent, and if it exists in every variety of cotton oil, a characteristic test for the material is thus given. Either the phloroglucinol-vanillin reaction or the test with potassium hydroxide may be employed to seek for the halogen; but if only a little cotton oil be present in the sample under examination, it is necessary to burn several C.C.In such cases the flame is best held under a funnel, which is connected with a set of bulbs containing the alkali, and thence with a pump, a blank experiment being conducted at the same time to insure purity of the potash and absence of hydro- chloric acid vapours in the laboratory atmosphere. Combustiowof 1 C.C. of au olive 04 mixed with 6 per cent. of cotton oil is sufficient to yield an indication of chlorine; if the former contains only I per cent. of the adulterant, 5 C.C. must be burnt. As the whole of the chlorine or bromine in an organic body is converted by P. N. Raikow. *THE ANALYST. 339 ignition into hydrochloric or hydrobromic acid, the .percentage of halogen in any combustible organic substance may be determined by operating in this manner. F. H. L. ’ [No reference is made to Charabot and March’s recent investigation (ANALYST, 1899, xxiv., 247), in which the existence in cotton oil af Dupont’s volatile sulphur compound was corroborated, and in which also the analogous sulphur coinpound in olive oil discovered by Dupont and Charabot was again mentioned.-Ass.]

ISSN:0003-2654    

DOI:10.1039/AN8992400332

出版商:RSC    

年代:1899

数据来源: RSC