448 ABSTRACTS OF CHEMICAL PAPERS ORGANIC ANALYSIS. Note on I d e n t i f y i n g Amino-H-Acids. (J. Ind. and Eng. Chem., 1915, 7, 674-675.)-E€-acid is 1,8-amino-napthol-3,6-disulfo acid. There are no published methods of identifying the 2-amino-H-acid, the 7- amino- H-acid, and the 2,7-diamino-H-acid. Ability to detect and differentiate these acids is frequently necessary for industrial purposes in obtaining light on the mode of making and the composition of certain coal-tar dyes.The 2-amino-H-acid was made from H-acid by coupling it in hydrochloric solution with diazotised p-nitraniline (1 mol.), reducing and separating the acid product from the p-phenylene diamine ; the 2,7-diamino-H-acid was made from the foregoing product and a further molecule of diazotised p-nitraniline, coupling in alkaline (carbonate) solution and treating the product a8 outlined below ; 7-aminO- H-acid was made from the coupling product of H-acid and diazotised p-nitraniline (1 mol.), coupled in alkaline (carbonate) solution. This product was reduced and separated as outlined below.B. C. Hesse. The reducing and separating methods mere as follows : One grm. of each of these products was mixed with 10 C.C.water, heated to 60" C., and added to 1 grm. zinc dust suspended in 5 C.C. water, shaken thoroughly, and 5 C.C. of a 36' Be. sodium bisulphite solution added. The whole was shaken thoroughly, then gradually raised to boiling, and maintained at boiling-point until further colour-change failed to take place. It was then filtered rapidly, cooled, and 6 C.C.hydrochloric acid (sp. gr. 1.16) were added to the cooled filtrate. The whole was next cooled in a freezing mixture to 0' C. or below, and maintained at that temperature until no more solid separated (this may take from half an hour to two or three hours), filtered upon paper through a Gooch crucible, and drained thoroughly. The material was washed carefully with small amounts of saturated salt solution; then with as little 95 per cent.ethyl alcohol as possible (3 to 4 c.c.), and finally with 1 or 2 C.C. of ether. The solid was then removed from the filter- paper and dried on a watch-glass at 90° C. The solid so obtained is the amina-H- acid of the coupling product used. The three identification tests used were as follows : 1. A fraction of a mgrm.of the free acid is boiled with a few drops of 40 per cent. caustic soda solution, diluted with 1 C.C. water, and the colour produced noted. I t was found that boiling of the diluted solution wits at times necessary.ORGANIC ANALYSlS 449 2. A fraction of a mgrm. of the free acid is placed in 2 or 3 drops of concentrated H,SO, (sp. gr. 1-84), and warmed until it begins to turn violet ; 1 or 2 drops of 0.5 per cent.sodium nitrite solution are added, and the whole cooled, and then diluted with 0 5 C.C. water. If a brown opalescenco or turbidity appears at this point, the solution has been heated to too high a temperature. The solution is next made alkaline, first with caustic soda in slight excess, and then with saturated carbonate of soda solution, and the colour-changes noted.3. A fraction of a mgrm. of the free acid is dissolved in 1 drop of saturated carbonate of soda solution, heat being used if necessary. One drop of concentrated hydrochloric acid is added, and the solution diluted with water to 0.5 c.c., is heated f o boiling, and cooled. A drop of this is placed on white filter-paper, and a drop or two of hydrogen peroxide solution added.When the colour development has reached its maximum, a drop of 40 per cent. caustic soda solution is added. The colour-changes are then noted. The behaviour of these acids is tabulated as follows : Test. 2-Acid. 7-Acid. 2,7- Acid. I. ... Yellow or brown. Green. Violet going to blue. 11. ... Blue-red. Blue-red. Yellow or brown. 111. H,02 Brown or yellow.Violet to red. Blue. NaOH. ... Red. White or cream- Red to violet. coloured. By suitably combining these tests, it is possible to detect all three of these acids in mixtures of any combination. With care 200 mgrms. of H-acid dye are sufficient to carry out this separation and all three of these tests. The colours produced by Test 111. are unstable and can be photographed--e.g., on a Lumidre plate-and the colours so preserved for reference.H. P. E. H. Separation and Determination of Peptones by their Solubility in Methyl and Ethyl Alcohols. E. Valhuta. (Bull. Acad. Ronzha, 1914-15, 3, 290-300; through J. Chem. SOC., 1915, 108, i. 602-603.)-The peptones resulting from the partial hydrolysis of a number of different proteins obtained from various sources, using Fischer's method, were separated into four fractions, varying i n their solubilities in methyl alcohol.The protein material was added in small quantities to 70 per cent. sulphuric acid at 0" C. with constant stirring, and kept at this temperature for two hours. The mixture was kept for three days at the ordinary temperature with frequent stirring, and then poured into 20 litres of distilled water at 0" C., and the sulpburic acid was just completely precipitated with barium hydroxide.The barium sulphate was filtered off, and the filtrate evaporated to dryness at 36" to 40" C. under reduced pressure (15 mm,). The peptone residue vvas divided into four fractions as follows : The peptone was extracted with hot methyl alcohol and filtered, the insol- uble portion being fraction I.The filtrate on standing for twenty-four hours gave a deposit, fraction II., which was filtered off. The filtrate on dilution with an equal volume of ethyl alcohol gave a further deposit, fraction III., and the filtrate from this on evaporation in a vacuum at 35' to 40° C. left a residue, fraction IV. These four450 ABSTRACTS OF CHEMICAL PAPERS fractions, of which all but the first were invariably easily soluble in water, were tested in aqueous solution by the biuret reaction, Millon's reagent, for cystine, for tryptophane, and for precipitation with the usual protein precipitants.I n addition the ash content was determined and the optical rotation measured. This method was applied to the gluten of wheat, the protein of beef, the protein of fish, the albumin of eggs, the casein of milk, and keratin.The results obtained show that. the peptones bear the mark of their origin. Thus, from proteins rich in cystine or tyrosine, peptones were obtahed also rich in these substances and vice versa. Hydrochloric Acid-Ether Mixture as a Reagent for Rubber Analysis. D. F. Twiss. (India Rubber J., 1915, 50, 199 ; through J.SOC. Chem. Ind., 1915,34, 914.)-The author has employed a mixture of equal volumes of concentrated hydro- chloric acid and ether for the purpose of removing mineral accelerators (PbO, etc.} from partially cured mixings containing high proportions of these substances and free sulphur, in order to be able to estimate with accuracy the originally combined sulphur. If such rnixings be extracted direct with acetone, further combination of the sulphur may occur during the extraction. Two samples, each of 1 to 2 grms.of the rubber, are treated with the mixture of acid and ether until the reagent has completely penetrated the mass. The rubber mass is removed, or the ether is distilled off', and the mass washed in running water and dried, after which it is extracted with acetone.The total sulphur is then estimated in one extracted sarnple and the mineral sulphur (sulphates) in the other. The difference is sulphur in organic combination, which, in the absence of substitute, means sulphur of vulcanisation (c$ Stevens, J. SOC. Chem. Ind., 1915, 34, 724). This takes about a day. Study of Some Recent Methods for Estimation of Total Sulphur in.Rubber. J. B. Tuttle and A. Isaacs. (J. Ind. aizd Eizg. Chcm., 1915, 7, 658-663.). -This paper is published by permission of the Director of the U.S. Bureau of Standards, and describes experiments directed to assess the value of several recent methods in respect of securing greater accuracy or saving time, by comparison. with the method of Waters and Tuttle, which has been in use by the Bureau for four years.This method (J. Ind. and Eng. Chem., 1911, 3, 734) is carried out as follows : The rubber (0.5 grm.) is placed in a large (100 c.c.) porcelain crucible, covered with 20 to 25 C.C. nitric acid saturated with bromine, and allowed t o stand an hour in the covered crucible. The crucible is then gently heated for an hour, the cover removed and rinsed, and the contents evaporated to dryness.About 5 grms. of a mixture in equal proportions of potassium nitrate and sodium carbonate and 3 to 4 C.C. of water are added, the mixture digested for a few seconds on the water-bath, and then spread half-way up the side of the crucible to facilitate drying. When dry, the mixture is fused over a spirit-lamp until all organic matter has been destroyed, and the melt is quite soft.The crucible and contents are cooled, placed in a large beaker, covered with distilled water, and heated on the water-bath for 3 to 4 hours. The solution is filtered and the insoluble matter washed well. To the combined filtrate and wash- ings, amounting to about 500 c.c., 7 or 8 C.C. of hydrochloric acid are added, theINORGANIC ANALYSIS 451 beaker covered, and the mixture heated almost to boiling.If the directions have been followed exactly, the solution will be slightly acid, but it should be tested with Congo red paper and a few drops more acid added if necessary. About 10 C.C. of 10 per cent. barium chloride are added, and the precipitated barium sulphate is filtered off next day, washed, and ignited in such a manner that the paper does not inflame.None of the othsr methods investigated gives results as accurate as those obtained by that above described. The methods of Spence and Young (J. I n d . and Eng. Chem., 1912,4,413) and Deussen (Zeitsch. angew. Chem., 1913,24,494), which depend on direct solution by nitric acid, give low results. The direct fusion methods of Alexander(Gummi Zeit., 1904, 18, 729 ; Allen’s Commercial Organic Analysis, 1911,4, 140), of the Joint Rubber Insulation Committee (J.Ind. a d Eng. Chem., 1914, 5, 78), and of Kaye and Sharp ( I n d i a Rubber J., 1913, 44, 1189), are satisfactory only when the free sulphur content is relatively low. As they are satisfactory in these circumstances, it is suggested that they might perhaps be applied to any class of rubber, after removal of the free sulphur by extraction with acetone. In such cases they would not estimate total sulphur directly, but only that insoluble in acetone, but as the free sulphur is usually estimated in vulcanised goods, the total sulphur would be found without any additional work.The suggestion was not followed up, as none of these methods is appreciably simpler or quicker than that of Waters and Tuttle.The method of Frank and Marckwald (Gummi Zeit., 1903, 17, 71) requires solution and fusion like the method of Waters and Tuttle, but it appears to be untrustworthy when much free sulphur is present. Although not covered by its title, the paper includes criticism of the attempt of some authors to estimate sulphur other than that present as sulphate in the mixing. Spence and Young, Alexander, and Kaye and Sharp, filter from an acid solution, basing their separation on the incorrect assumption that the lead .sulphate originally present will remain insoluble, while that formed from litharge will be dis- solved completely. Deussen filters from an alkaline carbonate solution, overlooking the fact that lead sulphate will react with sodium carbonate, with the formation of soluble sodium sulphate (cf. Gaunt [ANALYST, 1915, 91, Schidrowitx [ibid., 1915, 223.3, and Stevens [ibid., 1915, 2751). G. C. J.