380 Mr. P. Griesa on a New Class of Compounds [June 16, 



Diazobenzolimide in alcoholic solutions is decomposed by nascent hydro- 

 gen, generated with zinc and sulphuric acid in the following manner : — 



€,H,N3 + 8H=€3H,N + 2NH3. 



Diazoben- Aniline, 

 zolimide. 



On adding to an aqueous solution of nitrate of diazobenzol levigated 

 carbonate of barium, a feeble evolution of gas ensues, which lasts for several 

 days, until the original compound has been completely decomposed. 

 Two new substances are formed, which are very differently soluble in alco- 

 hol, and can thus readily be separated. The easily soluble compound, 

 which I will call phenyldiazobenzol, crystallizes from alcohol in yellowish 

 warty masses ; from water (in which it dissolves very difficultly) in small 

 rhombic prisms. The difficultly soluble one, which I propose to call phe- 

 nyldidiazobenzol, crystallizes in reddish-yellow needles. The following 

 equation expresses the formation of these two bodies : — 



I. 2(€JI, N,, NHO 3) + H, O =C\JI,, N,+ 2NHO3. 



Nitrate of diazobenzol. Phenol- 



diazobenzol. 



XL 3(63 H, N„ NHO3) + H, 0=-G,3 H,,N,0 + N,+3NH0,. 



Phenol didiazo- 

 benzol. 



On looking at these formulae, it becomes evident at a glance that both 

 compounds contain phenylic acid and diazobenzol ; viz. 



^/ 



Diazobenzol. Phenol. Phenol- 



diazobenzol. 



Diazobenzol. Phenol. Phenol- 

 diazobenzol. 



Both compounds are weak acids ; the first being capable of forming a 

 well-characterized silver-salt, which is obtained in the form of a blood- red 

 precipitate when an ammoniacal solution of phenoldiazobenzol is treated 

 with nitrate of silver. 



On heating the platinum- salt of diazobenzol mixed with carbonate of 

 sodium in a retort, chlorobenzol is obtained, the formation of which may 

 be expressed as follows : — 



OgH^N,, HCl, ViQ\=G,ll, Cl-}-N, + PtCl,. 



Platinum-salt. Chlorobenzol. 



A similar decomposition ensues when the dibromide is heated with carbo- 



