Mr. Noad on the Action of Nitric Acid on Cymol. 19 



and from the small amount of camphogene obtained, I found 

 it otherwise, and I merely prepared a sufficient supply to en- 

 able me to obtain an additional proof of the identity of the 

 two oils, which I did in a manner hereafter to be described. 

 I may remark that even after repeated distillations with re- 

 newed quantities of anhydrous phosphoric acid I was unable 

 to procure camphogene quite free from the peculiar smell of 

 camphor, nor was there to be discovered in it the slightest 

 approach to that fragrant odour by which cymol is charac- 

 terized. 



Action of Nitric Acid on Cymol. 



The action of nitric acid on cymol or camphogene has never 

 hitherto been the subject of minute examination. Gerhardt 

 and Cahours in their paper only mention that nitric acid of 

 moderate concentration does not attack cymol when cold; 

 that on heating nitrous acid is disengaged, and the carbo- 

 hydrogcn gradually passes into a peculiar acid, which on 

 cooling is precipitated as a curdy mass ; that this acid is ra- 

 ther soluble in water, alcohol and aether, crystallizing only 

 with difficulty, and decomposed by heat, partially subliming 

 in fine light needles or woolly flakes ; and that fuming nitric 

 acid decomposes cymol with the formation of the game acid 

 and a yellow resin ; none of these substances were however 

 submitted by these chemists to elementary analysis. Delalande 

 states that on treating camphogene with boiling fuming nitric 

 acid it is converted into a white solid matter, becoming cry- 

 stalline in the acid, and containing nitrogen. From these 

 statements it seemed evident that the action of nitric acid on 

 cymol gives rise to a variety of bodies, a supposition which 

 experiments have completely verified ; indeed, by a careful 

 examination of this reaction, I have ascertained that not less 

 than five or six different substances are produced ; these bo- 

 dies, some of which are acid, and some of a neutral character, 

 are separated with considerable difficulty. In the present 

 memoir I propose to confine myself to the acids only, re- 

 serving the regular substitution products of cymol, with the 

 basic bodies ai-ising therefrom, the substances representing 

 nitrobenzol, aniline, &c., in the cymol series for a future paper. 



I commenced with fuming nitric acid of the highest degree 

 of concentration, the action of which on cymol is exceedingly 

 violent ; to avoid explosions it was necessary to keep the ves- 

 sel cool by immersion in water ; the oil was added gradually, 

 drop by drop, to the acid, which speedily became of a dark 

 red colour; by repeated distillations I obtained a beautiful 

 crystalline acid, the analysis of which, leading to the formula 



C2 



