502 M. Strecker on a new class of Nitro-compounds. 



into NH 2 (amide). Strecker has now found that by the action 

 of sodium on nitro-compounds, oxygen is simply removed, and 

 thus a class of entirely new compounds is formed. The first 

 experiments were made with nitrobenzoic acid, which was pre- 

 pared by Gerland's method. 



When a concentrated solution of this acid was treated with 

 sodium-amalgam, no trace of hydrogen was given off, and the solu- 

 tion became so much heated that it had to be artificially cooled. 

 The liquid became transiently yellow, and finally assumed an 

 orange-yellow colour; no trace of ammonia was liberated. 

 When dilute acid was added to the boiling solution to which 

 alcohol had been added, a pulverulent precipitate was obtained, 

 which could be readily collected on a filter and washed. This 

 is a new organic acid ; Strecker names it Azobenzoic acid. It is 

 very difficultly soluble in water, alcohol, and ether; so that it 

 cannot be recrystallized from these media. It dissolves in sul- 

 phuric acid, and is reprecipitated on the addition of' water. It 

 loses nothing in weight, either at 100° or at 170° C, and at a 

 higher temperature melts, emitting a yellow vapour. Analysis 

 gave for it the formula C 28 H 11 N 2 O 9 ; and it is probable that it 

 contains an atom of water, which is of the nature of water of 

 crystallization ; its formula would thus be C 28 H 10 N 2 O 8 + HO : 

 for the dry acid the simplest expression is C 14 H 6 N0 4 ; and its 

 formation would then be thus expressed, 



C 14 H 5 (N0 4 )0 4 + 4Na=C 14 H 5 N0 4 + 4NaO. 



Nitrobenzoic acid. Azobenzoic 



acid. 



It dissolves in ammonia, caustic and carbonated alkalies. Its 

 ammoniacal solution loses on evaporation in water part of its 

 ammonia, and leaves an acid ammonia-salt. 



When a solution of azobenzoate of ammonia is added to chlo- 

 ride of barium at the boiling temperature, an orange-yellow 

 granular precipitate, consisting of microscopic rhombic laminae, 

 is deposited, which is almost insoluble in alcohol. The air-dried 

 salt has the formula BaO, C ,4 H 4 NO 3 + 5 HO, of which it loses 

 4 equivs. of water at 100°, and apparently another equivalent at 

 140°. 



Azobenzoate of lime is obtained in the same way as the baryta- 

 salt. Azobenzoate of silver is a pulverulent yellow body, which 

 contains no water, and has the formula C 14 H 4 Ag NO 4 . Azo- 

 benzoic ether (C 18 H 9 N0 4 = C 4 H 5 0,'C 14 H 4 NO 3 ) is best obtained 

 by adding sodium-amalgam to nitrobenzoic ether slightly acidi- 

 fied by acetic acid. Crystallized from alcohol, it forms splendid 

 long lustrous needles. When heated in a close tube with am- 

 monia, the amide of azobenzoic acid appeared to be formed; 



