MR. ALFRED NOBLE ON By ALFREDNOBLE ASSLSTANT IN THE ROYAL COLLEGE OF CHEMISTBY. WHILEconverting nitrobenzole into aniline by &I. A. Bechamp’s modification of Zinin’s process I observed a few facts which I beg permission to lay before the Chemical Society. M. Bhchamp’s process consists in reducing the nitrobenzole by a mixture of iron filings and acetic acid ; and his method is remarkable for the facility with which the conversion of the nitrobenzole is effected,-the former method as chemists will recollect being slow and extremely imperfect. The proportions recornmended by M. B6champ* are 2 parts of nitrobenzole 2 parts of acetic acid and 3 parts of iron filings. In an experiment in which the amount of iron was considerably increased above the proportions indicated I found that the result of the operation materially differed from what hi.Be‘champ had observed. The first portion of the distillate as in 11.B6champ’s process consisted essentially of aniline mixed * Ann. Ch. Phys. xlii. AZOBENZOLE AND BENZIDINE. with a small amount of nitrobenzole which had escaped decom-position ; whilst the last product,-about one-third of the whole -was a liquid of a deep red colour which solidified in the neck of the retort and in the condenser-tube into a beautifully crystalline com- pound. The results of several repetitions of this operation satisfied me that the largest quantity of this substance was obtained if the amount of iron employed was double that recommended by M. B6champ viz.3 parts of iron to 1of nitrobenzole and 1of acetic acid. This red crystalline substance was purified by washing first with HC1 (to separate any adhering aniline) then with water and after- wards dissolving in boiling alcohol when on cooling yellowish-red crystalline plates were deposited. These crystals were recrystallised once more from alcohol and dried in the water-bath at which tempe- rature they fused their composition was determined by a combus- tion with oxide of copper. 0.26 grm. of substance gave 0*755grm. of CO, and 0.134 grm. of HO. These numbers lead to the formula of azobenzole C,,H,N as may be seen from the following comparison of the theoretical and experi- mental numbers :-Theory. Equivalent. Percentage. Experiment. c, NH5- .. . . ’ 72 5 14 79.12 5.49 15.39 79.19 5.69 - - 91 100~00 Perfectly pure azobenzole may be obtained in this manner with greater facility than by any other process. A portion of azobenzole obtained by the above method was con-verted into benzidine by Zinin’s well-known process viz. by treating an alcoholic solution of this substance with ammonia and sulphuretted hydrogen. An analysis of the platinum-salt of the base thus obtained furnished an additional proof of the identity of the substance obtained as described above with azobenzole. 0.268 grm. of platinum-salt gave 0.088 grm. of platinum = 32.88 per cent. of 1%. DH. MATTHlESSEN ON BARIUM. The formula C,,H6N HC1 Pt C12 rquirea 33.09 per cent. of platinum. Benzidine exhibits a very interesting deportment with nitrous acid when it is gently heated in the gas of this acid as obtained by treating starch with nitric acid a powerful reaction is observed.The substance assumes an orange-red colour and exhibits after being treated with water and crystalliaed from alcohol all the properties of' azobenzole. The fact cd the reproduction of this body from benzidine was moreover established by a combustion which furnished the following numbers :-0,315grm. of substance gave 0.623grm. of CO, and 0.112 grm. of HO. Theory. Cl2 ' /-Equivalent. . 72 \ Percentage. 79.12 Experiment. 79.02 H5 . 6 5.49 5.78 N . . 14- 15-39 - 91 100*00 The simplest formulae for azobenzole and benzidine only differ by 1equivalent of hydrogen-Azobenzole . . Benzidine . . -a relation whicb sufficiently explains the transformation and repro- duction of azobenzole.