310 



of nitrogenous acids which are generated by the action of nitrous 

 acid on the amidic acids of the benzoic group, the change consisting 

 in the substitution of one equivalent of nitrogen for three equivalents 

 of hydrogen in two molecules of the amidic acid. 



Two eqs. benzamic New acid, 



acid. 



Under the influence of various agents these new acids undergo 

 remarkable changes, amongst which the transformation produced by 

 the mineral acids deserves to be particularly noticed. If the acid 

 C 28 H u N 3 O 8 be gently heated with strong hydrochloric acid, nitrogen 

 gas is evolved, the yellow colour of the original acid disappears, and a 

 red body separates, which may be separated by filtration and purified 

 by treatment with animal charcoal. Both the physical properties 

 and the analysis of the substance thus obtained, prove it to be pure 

 chlorobenzoic acid. The hydrochloric mother-liquor on evaporation 

 deposits crystals of the hydrochlorate of benzamic acid. 



C 28 H n N 3 8 + 2HC1= C 14 (H 5 Cl) O 4 + C M (H 5 H 2 N) O 4 , HC1 + N 2 . 



To render intelligible this transformation, the acid C 28 H n N 3 O 8 

 may be viewed as a double acid corresponding to two molecules of 

 water, 



C 14 (H 8 N' a )O a 1 



C u (H 4 H 2 N) 2 X0 4 =C 14 (H 4 N' 2 ) O 4 + C U (H 5 H 2 N) 4 , 



and splitting under the influence of hydrochloric acid into the two 

 groups C 14 (H 4 N' 2 )O 4 and C 14 ( H 5 H 2 N) O 4 , in the first of which 

 the two equivalents of monatomic nitrogen are replaced by hydro- 

 chloric acid, producing C 14 (H 5 C1)O 4 , while the second simply com- 

 bines with hydrochloric acid, producing hydrochlorate of benzamic 

 acid. It deserves to be mentioned that the acid C 28 H u N 3 O 8 may 

 be derived also from two equivalents of hydrated oxide of ammo- 

 nium, when its formula assumes the following shape : 



[(C 14 H 4 2 ) 2 "N"'HN 2 ]" 



Further experiments are necessary to decide which of these two 

 formulse deserves the preference. 



