311 



lodobenzoic Acid, C 14 (H 5 I)O 4 . 



This substance is produced by a process similar to that which 

 furnishes the chlorobenzoic acid, viz. by the action of hydriodic 

 acid on the acid C 28 H u N 3 O 8 , beautiful white plates resembling 

 benzoic acid, easily soluble in alcohol and in ether and difficultly 

 soluble in water. lodobenzoic acid is remarkable for its great 

 stability ; even fuming nitric acid fails to expel the iodine, and 

 transforms the substance simply into nitro-iodobenzoic acid. The 

 silver salt of iodobenzoic acid is a white amorphous precipitate con- 

 taining C M (H 4 1 A g) 4 . 



lodotoluic Acid, C 16 (H 7 1)O 4 . 



This acid is formed from the analogous nitrogenous acid in the 

 toluic series, according to the equation 



It crystallizes in white plates of a pearly lustre, which in their che- 

 mical and physical properties are very similar to iodobenzoic acid. 



lodanisic Acid, C 16 (H 7 1) O 6 



is obtained by the action of hydriodic acid upon the nitrogenous 

 acidC 32 H 15 N 3 12 , 

 C 32 H 15 N 3 12 +H 2 I 2 =C 16 (H 7 I)0 6 + C 16 (H 7 H 2 N)0 6 ,HH-N, 



Exceedingly small, nearly white needles, almost insoluble in boiling 

 water, very soluble in alcohol and in ether. 



The new method of substitution, by which the described products 

 were obtained, although less direct than the ordinary processes, 

 promises nevertheless to adapt itself to several cases of special interest. 

 I am at present engaged in pursuing these experiments, with the view 

 of producing fluo- and cyano-benzoic acids and their homologues, 

 which have never been obtained. 



The experiments which I have described were performed in Pro- 

 fessor Hofmann's laboratory. 



