111 XIII.-Preliminary Note on some Diazo-derivatives of Nitrobenzyl Cyanide. By W. H. PERKIN, Ph.D., F.R.S. SOME time since, while making some experiments with benzyl compounds, I prepared nitrobenzyl cyanide, not knowing that it had already been examined by Radziszewsky (Ber., 3, 198). It was treated with alcoholic potash to see whether, like benzonitrile, it would yield its acid, nitrophenylacetic acid. In making this experiment, I was very much struck with the remarkable action of this reagent upon it, an intense crimson colour being produced. This colour, however, soon becomes of a brownish-purple, and after a time changes to a dirty greenish-blue. This peculiar action of alkalis on nitrobenzyl cyanide has already been noticed by Czumpelik (Ber., 3, 474). From the intensity of the colour developed in this reaction, it appeared to me that some definite body must be produced, and as I was curious to get an idea of its nature, it was thought that it might perhaps form some compounds with diazo-compounds, and on trying this, the following results were obtained : An alcoholic solution of nitrobenzyl cyanide was mixed with some alcoholic potash, and directly after an aqueous solution of diazobenzene chloride was added until the crimson changed to a yellowish colour. The mixture, which contained a brown precipitate, was further diluted, the solid product collected on a filter, washed and purified by crystallisation from alcohol, and then from glacial acetic acid. In this way a substance was obtained, crystallising in orange-yellow needles; under some conditions, however, it is deposited as an orange-red crystalline powder. It melts at 201-202°, and on analysis gave numbers corresponding with the formula C1H1N,O2. Its alcoholic solution gives with alkalis a compound which is of a beautiful violet colour; this colour disappears on the addition of an acid. The constitution of this body has not yet been fully worked out, but it appears to be analogous to the compound lately described by Tiemann, viz., the phenylaniloacetic nitril with the diazo-group in place of C.H, HN, thus C&H,.CH(NHC,H1).CN. CH,NO2CH(N=NC,H1)CN. The formation of this body is apparently analogous to that of VOL. XLIII. I azon itroethylphenyl from sodium-nitroethane and a diazobenzene salt described by Victor Meyer and Ambuli (Ber., 8, 781, 1073). Other diazo-compounds also combine with nitrobenzyl cyanide, and the further study of these compounds is being carried on. Endeavours are also being made to introduce other than diazo-radicals. When preparing the ordinary nitrobenzyl cyanide, which appears to be the para-compound, I obtained a second body fusing at about 45°, which no doubt will prove to be orthonitrobenzyl cyanide. XIV. Researches on the Induline Group. (Part I.) By OTTO N. WITT, Ph.D., F.C.S., and EDWARD G. P. THOMAS. THE term "Induline" is applied in commerce to a series of violet and blue dyes, less brilliant than the majority of artificial colouring matters, but distinguished by great fastness to light and atmospheric influences. Scientifically, the term may be applied to all coloured compounds formed by the action of amidazo-compounds on the hydrochlorides of aromatic amines, with elimination of ammonia. Some of them may be obtained by other well-known processes, which need not be mentioned here, as the object of this paper is to lay before the Society an account of our researches on the formation of amidazobenzene and its action on aromatic hydrochlorides. These researches were begun in January, 1876, and continued, with occasional interruptions, up to the present time. They have been partly embodied in the specifications of certain patents, which we have taken out in different countries. It has long been known that amidazobenzene, treated with aniline hydrochloride or nitrate, produces a dark-blue coloration; but as far as we have been able to ascertain, this reaction had not been carefully investigated, or turned to practical account until we began to study it. This was probably due to the supposed impossibility of producing the necessary quantities of amidazobenzene. Our efforts to overcome this difficulty resulted, however, in an easy method of preparation— a method which was discovered independently in 1878 by Mr. Grässler, of Cannstatt. In studying the action of amidazobenzene on aniline hydrochloride, we soon found that it was much more complicated than was generally supposed. Hofmann and Geyger (Ber., 1872, 5, 474), who studied this action in 1872, state that only one dye-stuff is formed simul taneously with ammonium chloride, and they represent its formation by the formula C12HN3+C,H,N C18H15N3+ NH3. Although we have varied the conditions of our experiments in every possible way, we have been unable to effect so simple and complete a transformation. We have observed on the contrary : I. That the reaction invariably results in the formation of several colouring matters, differing from each other both in composition and in properties. II. That the nature of the products formed, as well as the quantities in which they are obtained, are largely dependent upon the temperatures at which the reaction takes place, and the manner in which it is conducted. In the present paper we purpose to confine ourselves to a description of those compounds which we have obtained in a state of purity, as well as of their mode of preparation, leaving it, we hope, to a subsequent communication to explain their constitution, and establish a theory of the whole reaction. Most of these compounds have acquired importance as commercial products. In order to avoid confusion and new names, we shall retain the commercial designation for the pure substances. The following is our Process for the Production of Indulines on the Large Scale. We first prepared diazamidobenzene by one of the well-known processes for the production of that body. If properly prepared, it consists of a granular crystalline substance of yellow colour, which becomes brownish on drying. In order to transform it into amidazobenzene, we first tried the method indicated by Kekulé ("Benzolderivate," p. 206), but we soon found that it was quite useless for our purpose. Alcohol, in this, as in most cases where diazo-compounds are to be dealt with, proved most detrimental to the reaction. We therefore tried other solvents, and found that aniline was by far the best. It has the advantage of being an excellent solvent for both diazamidobenze and aniline hydrochloride, and this greatly facilitates the reaction of the two substances. If a mixture of 2 parts diazamidobenzene, 1 part aniline hydrochloride, and 4 parts aniline be left at a gentle heat for 24 hours, not a trace of nitrogen is formed, but the whole of the diazo-compound is transformed into amidazobenzene. The latter may be separated by treating the mixture with sufficient hydrochloric acid and water to dissolve all the aniline. Crude hydrochloride of amidazobenzene settles out in bluish glistening needles, and may be collected and washed with dilute hydrochloric acid. From this crude salt a pure substance may be prepared by washing with dilute ammonia, which frees the base. The latter is dissolved in pure boiling benzene. On cooling, fine yellow crystals settle out, which consist of a molecular combination of amidazobenzene with benzene. On drying, the benzene is driven off, whilst pure amidazobenzene remains in the form of a brilliant yellow powder. On recrystallisation from alcohol, it is obtained in magnificent orange prisms having a blue reflex, and melting at 125-126°. Another process consists in basifying the mixture of aniline, amidazobenzene, and aniline hydrochloride by means of caustic soda, washing with water, and drawing off the aniline with steam. Crude amidazobenzene then remains in the still, and may be purified by dissolving it in spirit, adding hydrochloric acid, collecting the crude hydrochloride which settles out on cooling, and treating it as above described. Amidazobenzene was formerly tried as a yellow dye-stuff, but abandoned on account of the difficulty then experienced in its production, and its sensitiveness to mineral acids. Recently, however, it has become an important article of manufacture, Grässler having shown that its sulpho-derivatives are excellent yellow dyes, not too sensitive to mineral acids. For the production of the different indulines, it is not necessary to separate the amidazobenzene from the liquid in which it was formed. This liquid, besides the amidazobenzene, consists, as already stated, of aniline and the whole of the aniline hydrochloride originally used. This aniline hydrochloride reacts upon the amidazobenzene formed, if the temperature of the mixture be raised, and the free aniline present facilitates and moderates the reaction. According to the quantity of aniline and aniline hydrochloride present, and especially to the temperature at which the reaction takes place, the products obtained differ in their properties and composition. If the mixture referred to be heated for 24 hours on the water-bath, and below the temperature at which there is any formation of colour, it deposits an abundant crystallisation of a compound which is not an induline, but which, in the formation of indulines, seems to play so important a part that it cannot be passed over in silence. To prepare this substance in the pure state, it is sufficient to mix the mass from which it partly separates with strong spirit, and filter off the brown crystalline precipitate from the mother-liquor. After washing with spirit and water, the precipitate is dissolved in boiling aniline, from which, on cooling, it settles out in beautiful garnet-coloured leaflets. These, after filtering and washing with boiling spirit, are quite pure and fit for analysis. The melting point of this substance is 236-237°. It dissolves in concentrated sulphuric acid with violet coloration, which, on heating to 300°, suddenly becomes sky-blue. The solution, if mixed with water, exhibits a fine crimson fluorescence. These reactions show that the substance is identical with that described by one of us as being one of the products of decomposition of diphenylnitrosamine (O. N. Witt, Ber., 10, 1877, p. 1311). On studying the reactions of this compound, we were struck by their similarity to those of the body described by Kimich (Ber., 8, 1875, p. 1028), under the name of azophenine, and obtained by heating nitrosophenol with aniline acetate. Kimich, however, attributes to his substance the formula CH29N,O. He recrystallised it from toluene and xylene, which, as we have convinced ourselves, are incompetent to effect complete purification. We therefore conjectured the identity of Kimich's substance with our own, and, to verify the supposition, prepared azophenine according to Kimich's method from nitrosophenol. We found that on using aniline acetate, a very small yield of an impure substance was obtained; whereas on heating nitrosophenol with aniline hydrochloride for 24 hours on the water-bath, an abundant yield of azophenine was the result. This, purified by the process described, gave a substance free from oxygen, and in every respect identical with our own. It follows, therefore, that Kimich's azophenine was an impure substance. We propose, however, to retain for the purified product Kimich's name azophenine, and we will henceforth so call the body C28H29N5. On reduction with tin and hydrochloric acid, azophenine gives a mixture of several bases, amongst which we have been able to identify aniline and paraphenylene-diamine. On heating it with paraphenylene-diamine hydrochloride in presence of aniline, it quickly disappears, yielding a violet melt. Heated with metaphenylene-dia |