68 On the Oxidation of Cumol by Nitric Acid. 



I therefore distilled a fresh quantity of cumol with nitric 

 acid, and recollecting the difficulty Mr. Noad experienced in 

 the preparation of toluylic acid, I employed my acid so dilute 

 that even on boiling the mixture no disengagement of red 

 fumes was visible. Having continued the distillation for four 

 or five days the cumol was converted into a crystalline mass, 

 which was strained off from the mother-liquor and recrystal- 

 lized from water. The properties of this acid distinguished 

 it immediately from nitrobenzoic acid ; it was much more 

 soluble in cold and hot water, and might be easily recognised 

 as benzoic acid. Not having sufficient substance for a com- 

 bustion, 1 converted the acid into an ammoniacal salt, and 

 precipitated this with nitrate of silver. A white flocculent 

 precipitate was obtained, much more easily soluble in water 

 than nitrobenzoate of silver. On cooling, beautiful crystals 

 separated, having all the properties of benzoate of silver. 



The analysis of this salt gave me the following results : — 



I. 0"1837 gim. of substance yielded 0*1138 grm. chloride 

 of silver, corresponding to 0"OS57 grm. or 46*65 per cent, of 

 silver. 



II. 0-1658 grm. yielded O-O/SO grm., or 47-04 per cent, of 

 silver, which numbers correspond with the formula AgO, Cj4 

 Hj Og, as may be seen when compared with the theoretical 

 numbers. 



Theorv. Found. 



I. II. 



Benzoic acid . 11.3 49-35 



Oxide of silver . n6 50-65 50-08 50-50 



229 



These re&ults were sufficiently near, considering the small 

 amount of substance employed. 



From these experiments we see that cumol on being boiled 

 continuously with nitric acid is converted into benzoic and 

 nitrobenzoic acids. The oxidation of cumol is therefore ana- 

 logous to that of cymol. 



C20 Hi4 + 180 = HO, CigH^ O3 + 4C0, + 6H0. 



Cymol. Toluylic acid. 



C,3 H,2 + 180 = HO, C,4 H5 O3 -I- 4CO.i + 6H0. 



Cumol. Benzoic acid. 



The behaviour of cumol under the influence of the con- 

 tinued action of dilute nitric acid induced me to submit benzol, 

 so nearly related to cumol, to a similar treatment. After 



