Products of Oxidation of Cumol by Nitric Acid. 67 



former, which was purified in the usual manner. A combus- 

 tion of this body gave me the following results : — 



0*2628 grm. of substance yielded 0'4890 grm. carbonic 

 acid and 0-0743 grm. water. 

 Or in 100 parts, — 



Carbon .... 50*73 

 Hydrogen ... 3*18 

 These numbers correspond to the composition of nitro- 



benzoic acid, HO, Cj4-< ^rjk ^Og, as is seen when compared 



with the theoretical numbers. 



this acid a white precipitate was formed, sparingly soluble in 

 hot water, from which it crystallized on cooling. I had not suf- 

 ficient substance to recrystallize the salt, and could therefore 

 only purify it by washing. 



Its analysis gave me the following result : — 



0-1G57 grm. of substance left, on being burnt, 0-0650 grm., 

 or 39*24 per cent, of silver; which agrees sufficiently well 

 with the composition of nitrobenzoate of silver. 



Theoiy. Found. 



Nitrobenzoic acid . 158 57*67 



Oxide of silver . . 116 42-33 42*14 



274 100*00 



In order to be perfectly certain, the small quantity remain- 

 ing of the silver salt was submitted to distillation. There 

 sublimed a portion of the acid, mixed with a few drops of an 

 aromatic oil. The product of the distillation was therefore 

 submitted to Dr. Hofmann's process for detecting nitroben- 

 zol ; it was dissolved in a mixture of alcohol and sulphuric 

 acid, and reduced by means of a piece of metallic zinc. After 

 the disengagement of hydrogen had ceased, the liquid was 

 neutralized with potash and agitated with aether. A few 

 drops of tlie octherial solution gave, on evaporation with hy- 

 pochloride of lime, the beautiful violet colour characterizing 

 aniline. 



These experiments were sufficient to identify nitrobenzoic 

 acid, and it seemed more than probable that the excess of 

 carbonic acid obtained in the first analysis arose from the 

 presence of benzoic acid. 



F2 



