Products of Oxidation of Cumol by Nitric Acid. 65 



of the formation of an acid without the original number of 

 equivalents of carbon in the carbo- hydrogen being diminished. 



In the paper lately read before this Society by Mr. Noad, 

 he has shown that cymol is converted by the continued ac- 

 tion of dilute nitric acid into toluylic acid. 



It will be seen from these examples that we are unable to 

 determine anything beforehand regarding the nature of these 

 products of oxidation. The manner in which nitric acid or 

 any other oxidizing agent acts is evidently closely connected 

 with the constitution of the body exposed to their influence. 

 Aided by the manner in which nitric acid acts on naphthalol, 

 Marignac has in fact founded a view of the constitution of 

 this body. He considers the carbo-hydrogen in question to be 

 a combination of two others, namely, C,gH4 and C4H4 = C2oH8, 

 naphthalic acid, C,gH40g, being formed by the action of nitric 

 acid on the first, while the other is converted by the influence 

 of the oxygen into water and oxalic acid or carbonic acid. 

 By this view many of the reactions of naphthalol may be ex- 

 plained in a very satisfactors'^ manner. It is possible that 

 similar views may be applied to the other carbo-hydrogens, 

 by which their behaviour with oxidizing agents may be simi- 

 larly explained; a great number of investigations are how- 

 ever required before we can arrive at any general result. 



The following experiments, which I have instituted at the 

 suggestion and under the direction of Dr. Hofmann, may, I 

 hope, be considered as a slight contribution to this subject. 



It is known that when cumol is treated with concentrated 

 nitric acid it yields the usual products of substitution of the 

 carbo-hydrogens. Gerhardt and Cahours have observed fur- 

 ther, that by the continuous action of dilute nitric acid on 

 cumol a crystalline acid is produced*. This acid has not, 

 however, been more closely investigated. According to the ex- 

 periments on toluol, cinnamol and cymol before mentioned, 

 this acid might be of three different kinds, according to the 

 analogy of cumol with any one of these carbo-hydrogens. 

 If the number of equivalents of carbon were to remain the 

 same as in toluol, the acid obtained might be HO, Cjg Hg Og, 

 until now unknown (differing from toluylic or cuminic acid 

 in containing C^ H2, more or less). Should two equivalents 

 of carbon be eliminated, as is the case with cinnamol, the 

 formation of toluylic acid might then be expected ; and lastly, 

 should cumol be analogous to cymol, that is, should it lose 

 four equivalents of carbon, the acid must then be benzoic acid. 



In the ])rcparation of cumol I proceeded in the manner 

 described by its discoverers, Gerhardt and Cahours. Pure 



* Licbig's Aunnlcn, xxxviii. p. G7. 



Phil. Mag. S. 3, Vol. 32. No. 2 1 2. Jan. 1818. F 



