332 BENZOIC ACID. 



Azobenzoic acid, C 14 H 10 N 2 4 + JH 2 0. Is formed by 

 the action of sodium-amalgam on an aqueous solution 

 of sodium metanitrobenzoate, and is precipitated by 

 hydrochloric acid after the completion of the action. 

 Amorphous, bright yellow powder, very slightly soluble 

 in water, alcohol, and ether; not volatile without de- 

 composition. Very stable, bibasic acid ; yields crys- 

 tallizing, yellow colored salts, and ethers. Parazoben- 

 zoic acids (azodracylic acid), C 14 H IO N 2 4 . Is obtained 

 from paranitrobenzoic in the same way as azobenzoic 

 acid. Flesh-colored, amorphous powder very similar to 

 azobenzoic acid. 



Hydrazobenzoie acid, C 14 H 12 N 2 O. Is formed, when 

 a solution of iron sulphate is added to sodium azoben- 

 zoate, dissolved in an excess of soda-ley. The acid is 

 then precipitated from the filtered solution by means 

 of hydrochloric acid. Yellowish-white, indistinctly 

 crystalline flocks. Insoluble in water, difficultly solu- 

 ble in boiling alcohol. Weak acid. In aqueous solu- 

 tion, its. salts absorb oxygen from the air and are con- 

 verted into azobenzoates. When heated with concen- 

 trated hydrochloric acid, it is resolved into azobenzoic 

 and amidobenzoic acids. Paraliydrazobenzoic acid, 

 (hydrazodracylic acid), 14 H 12 ^ 2 4 . Small, lustrous, 

 crystalline needles. Is prepared like hydrazobenzoic 

 acid, and conducts itself like this. 



Azoxybenzoic acid, C 14 H 10 E" 2 5 , is produced by 

 boiling an alcoholic solution of metanitrobenzoic acid, 

 to which is added solid caustic potassa. Microscopical 

 needles or lamime. Insoluble in water ; difficultly so- 

 luble in alcohol and ether. Bibasic acid. 



Diazobenzoic acid, C 7 H 4 TO 2 . Is precipitated as a 

 yellow, very unstable mass, when an alkali is added to 

 a solution of nitric-diazobenzoic acid. Nitric-diazoben- 

 zoic acid, C 7 H 4 ]N" 2 2 .HN0 3 , is thrown down, when a 

 current of nitrous acid is conducted into meta-amido- 

 benzoic acid dissolved in cold nitric acid. Colorless 

 prisms, very easily soluble in cold water. Is decomposed 



