ON OUR PRESENT KNOWLEDGE OF AROMATIC DIAZO-COMPOUNDS, 205 



abnormally large hydrolytic dissociation of these substances. This is 

 explained by the hypothesis already employed in considering the con- 

 dition of the dissolved diazonium hydroxide. The s^Ji-diazo-oxide exhibits 

 n higher degree of hydrolytic dissociation than potassium cyanide or other 

 dissociating salts, because the acid set free by hydrolysis is not stable, 

 but passes into the intermediate hydi-ate and thence to the diazonium 

 hydroxide : — 



R.N ^_ R.KOH ,, ^ II.N.OH 



II + HoO -> TT..VTTT — H9O -> 



HON " HONH N 



Anti-diazo-oxides and Primary Nitrosamines. — The alkali diazo-oxides 

 behave like the salts of a distinctly acid substance, and are not greatly 

 hydrolysed in dilute solution. When the dissolved salt is treated with 

 the equivalent amount of hydrochloric acid, the electrical conductivity 

 of the resulting solution shows that the only electrolyte present is the 

 alkali chloride produced by the reaction. The solution obtained is per- 

 fectly neutral, and, conversely, when the substance, which is set free by 

 the acid, is treated with the equivalent quantity of alkali the product 

 is neutral. These phenomena indicate that the substance set free from 

 the au^i-diazo-oxide belongs to the class of pseudo-acids,' and accordingly 

 the product is best represented as being a primary nitrosamine, 



R.N n R.N -| 



II -> II \^ rnh.no 



NOK L NOHJ 



anti-diazo-oxicle. labile. stable. 



The nitrosamines Br.C.H^NH.NO and NO-^.C^H^NRNO have 

 the characters of pseudo-acids ; they do not react with phosphorus penta- 

 chloride, acetyl chloride, or ammonia in indifferent solvents, and dissolve 

 only gradually in acids regenerating the diazonium salts. 



Summary. — The theory of diazo-compounds, which ignores stereo- 

 chemical differences and assumes that the diazo-oxides are structurally 

 dissimilar, may be summarised in the following diagram : — 



R.N.Cl 



Ber., 1899, 33, 575, 1703, 



