The tetraphenylmethane as now obtained has been found to agree in all properties with the substance previously reported. It is insoluble in ether, chloroform, petroleum ether, glacial acetic acid. Fairly soluble in hot benzene, but very little in the cold. It crystallizes from benzene in white, glistening needles. The melting-point, determined this time in a closed dish and with a normal thermometer, was found to be 272° C. instead of 267.5°C., as given before. Recovery of the Tetraphenylmethane.-Nearly all the quantity employed in the determination of the molecular weight was recovered. The naphthalene was placed in a crystallizing dish and sublimed off at the lowest possible temperature. The residue was boiled out first with a little petroleum ether, and then thoroughly washed with ether. The white silky residue showed the correct melting-point of tetraphenylmethane, and amounted to 0.1075 gram. TETRANITROTETRAPHENYLMETHANE, (C,H,NO,),C. The quantity of tetraphenylmethane recovered from naphthalene after the determination of the molecular weight, was nitrated. The nitration was done according to the method employed by E. and O. Fischer' for the preparation of paratrinitrotriphenylmethane. The hydrocarbon was added in small quantities to two cc. of nitric acid (sp. gr. 1.50), cooled in icewater. The substance dissolved very readily. The bright yellow solution was allowed to stand about fifteen minutes. On the addition of water the nitro-compound separated in white minute crystals, without the slightest trace of any oily, sticky byproducts, as is always the case when triphenylmethane is nitrated. The crystalline precipitate was separated by means of a pump, thoroughly washed with water, alcohol, and finally with a little ligroin, and dried in vacuo over sulphuric acid. The yield was 0.166 gram, while theoretically 0.107 gram of tetraphenylmethane should yield o.1669 gram of the tetranitroderivative. The substance was analyzed with the following results : 0.1417 gram gave 14.8 cc. nitrogen at 24° and 737 mm. 1 Ann. Chem. (Liebig), 194, 254. N Calculated for Found. 11.68 The nitro-derivative, as already mentioned, consisted of minute, white, needle-like crystals. It is insoluble in ether, petroleum ether, alcohol; insoluble in cold glacial acetic acid, and only slightly when heated. It is somewhat soluble in hot benzene and hot chloroform, from either of which solvents it can be obtained in a nice crystalline form. It begins to darken at about 268° C., and melts at 275° C. Unlike the trinitrotriphenylmethane, or the trinitrotriphenylcarbinol, it does not dissolve in sodium ethylate, nor does it give any coloration with it even on heating. The non-formation of colored alkali salts, as well as the high melting-point, show the absence of any nitrotriphenylmethane. The nitration of the hydrocarbon has been repeated several tines on small quantities, five to ten milligrams, of the original tetraphenylmethane, which had not been employed for the determination of the molecular weight, but the results were in every respect identical with those described above. Reduction to a Rosanilin Dye.-About five milligrams of the nitro-compound were dissolved in boiling glacial acetic acid, and zinc dust gradually added in small quantities. On the first addition of the zinc the solution turned a bright red, and the reduction to a colorless base required considerable zinc dust and boiling. The solution was diluted with water, filtered from the excess of zinc dust, treated with excess of ammonia, and the precipitated colorless leuco-base was filtered and washed. The base was then gently ignited with a few drops of concentrated hydrochloric acid on a platinum foil, according to the method of E. and O. Fischer' for triphenylmethane. The characteristic fuchsin color so developed could not be distinguished at any stage from that produced by the reduction-product of p-trinitrotriphenylmethane. The two were reduced in about the same quantities and under the same conditions. The two dyes were dissolved in about the same amount of alcohol, and when examined spectroscopically, gave about the same absorption bands. Lack of material prevented me from establishing the identity of the dye. 1 Ann. Chem. (Liebig), 194, 273. The subject will be continued, and it is hoped that perhaps larger quantities of tetraphenylmethane will be obtained by the action of triphenyliodomethane upon mercury-diphenyl. ANN ARBOR, MICHIGAN. HYDRAZO- AND AZO-DERIVATIVES OF TRIPHENYLMETHANE.' O BY M. GOMBERG AND A. CAMPBELL. Received Angust 9, 1898. The NE of us has recently described a method by which small quantities of tetraphenylmethane were obtained. method involved the synthesis of triphenylmethaneazobenzene, which was obtained by the oxidation of the corresponding hydrazo-derivative. The azo-body, on being heated to 110°120° C., loses nitrogen, and furnishes, among other products, tetraphenylmethane. The present work was undertaken with the hope of obtaining substitution derivatives of tetraphenylmethane, by subjecting substituted azo-compounds of triphenylmethane to the same treatment as the simple azo-compound itself. For the present, we shall only give a description of the hydrazo- and azo-bodies, which have been prepared by us in connection with this work, The number of mixed azo-bodies, i. e., those containing an aliphatic and an aromatic radical, is quite limited. A few have been prepared by E. Fischer and Ehrhard,' and Tafel' by the oxidation of the corresponding hydrazo-derivatives. The principal method of preparation is, however, by combining aromatic diazo-salts with aliphatic compounds. This reaction, first worked out by V. Meyer on nitroethane, has since been extended to a large number of such aliphatic compounds, as contain a (CH,)-group linked to some negative groups. Nitrocompounds, malonic ester, aceto-acetic ester, etc., give such bodies. The constitution of all these so-called azo-bodies has, however, recently been called into question by the work of Japp 1 Read at the Boston meeting of the American Chemical Society, August, 1898. 2 Ber. d. chem. Ges.. 30, 2043; This Journal, 20, 773. 3 Ann. Chem. (Liebig), 199, 328, 1879; Ber. d. chem. Ges., 29, 793, 1896. 4 Ber. d. chem. Ges., 18, 1742, 1885. 5 Ber. d. chem. Ges., 8, 751, 1875: 18, 1742, 1885 2 and Klingmann,' and others, who have shown, for many compounds, the identity of the azo-formula, R.N: N.CH, with that of the hydrazo-formula, R.NHN: C This has opened the question, as to whether all the mixed azo-compounds, obtained by the above reaction, are not after all hydrazones. An intramolecular change of this nature can, of course, take place only in such compounds as contain a (CH)- or (CH)-group. If this view be correct, then the number of mixed azo-bodies is indeed very small. The phenylazoisovaleric acid of Prentice3 might be mentioned in this connection as being a true mixed azo-compound. We have found that the reaction of phenylhydrazine with triphenylbrommethane is of general application. All hydrazines, so far as tried, react very readily with this bromine compound, and give hydrazo-bodies, which furnish, on oxidation, with more or less readiness, the desired azo-derivatives. The following hydrazines have been tried: Paratoluylhydrazine, orthonitrophenylhydrazine, metanitrophenylhydrazine, paranitrophenylhydrazine, metachlorphenylhydrazine, parachlorphenylhydrazine, metabromphenylhydrazine, and a-naphthylhydrazine. These hydrazo-bodies are well crystallized; they are colorless, with the exception of those containing the nitro-group, which are colored yellow to reddish-brown. They are soluble in benzene, chloroform, less soluble in ether and alcohol, and very sparingly soluble in ligroïn. They oxidize very readily on exposure to the air, thus resembling more the aromatic than the purely fatty hydrazo-bodies. They are weak bases and form salts with dry hydrochloric, oxalic, picric, and other acids. The azo-derivatives are also well crystallized compounds, colored from yellow to orange. They are very soluble in benzene and chloroform, less soluble in ether, alcohol, and acetic acid, and only sparingly soluble in ligroïn. They all give off their 1 Ber. d. chem. Ges., 20, 3398, 1887; Ann. Chem. (Liebig), 247, 190. 2 R. Meyer: Ber. d. chem. Ges., 21, 118, 1888; 24, 1241, 1891; V. Meyer, 1888: Ber. d. chem Ges., 21, 11; Baeyer and Claisen: Ibid., 1697; 25, 746, 1892; v. Pechmann, 1892: Ber. d. chem. Ges., 25, 3190. 8 Ann. Chem. (Liebig), 292, 272. nitrogen on being heated, thus resembling the simple triphenylmethaneazobenzene. The liberation of nitrogen is quantitative, and takes place at temperatures ranging from 103.5° to 118.5° C. The relative position of the chlorine or the nitro-group seems to exert no particular influence upon the temperature at which the azo-body decomposes. Molecular weight determinations show them to be monomolecular. When dissolved in chloroform and treated with bromine, they form crystalline perbromides. These have not yet been analyzed. EXPERIMENTAL PART. ACTION OF PARATOLUYLHYDRAZINE. Triphenylmethanehydrazoparatoluene, (C,H,),C.NH.NH.C.H ̧. CH,.-Paratoluylhydrazine' (two molecules) was dissolved in dry ether and slowly added, with stirring, to a cold ethereal solution of triphenylbrommethane (one molecule). The solution was allowed to stand protected from the air until the precipitate of toluylhydrazine hydrobromide separated out. The reaction is represented by the following equation: (C ̧H ̧),CBr + 2H,NHNC,H,CH,= (C.H,),C.NH.NH.CHỊCH,+CH..CHNHNH HBr. Upon filtering off the precipitate of toluylhydrazine hydrobromide and concentrating the ethereal solution, white crystals of the hydrazo-body were obtained. They were recrystallized from ether and analyzed with the following results: 0.212 gram gave 15 cc. nitrogen at 20° and 736.6 mm. N Calculated for CH,Ng. ..... Found. 8.02 This hydrazo-derivative is readily oxidized on exposure to the air, especially in an alcoholic solution. It is a weak base, forming salts with dry hydrochloric, oxalic, picric, and other acids. It is soluble in benzene, chloroform, less soluble in alcohol and ether, and insoluble in water and ligroïn. It melts with decomposition at 157° C. Triphenylmethaneazoparatoluene, (C,H,),C.N: N.C,H,.CH,.— After trying numerous oxidizing agents, such as potassium per 1 E. Fischer, 1876: Ber. d. chem. Ges., 9, 890. |