TRANSFORMATION OF NITROAMINES AND ALLIED SUBSTANCES. 137 
The following experiment serves as a comparison when a chloroamine, 
which cannot yield an isomeride, is used :— 
65 per cent. HA H,SO, 16 days 8-25 per cent. 8-1 per cent, 
In the following experiments hydrogen chloride (1 molecular proportion) 
is initially present :— 
Per cent. 
Glacial puriss. Reaction complete. . . . . «. . . 3-24 
» ordinary. 3 ; , \ - ‘ : : PH6:0 
93-4 per cent. puriss. a NAS eeAD een Fanti’ Anscieeee 
75 per cent. puriss. Me RA lees: ok Ste cues ee el O4: 
There can be little‘doubt as to the manner of this reduction. In all 
aqueous media some hydrolysis of the chloroamine occurs :— 
Ar.NCl. NAc+ H,O = HClO + Ar. NH. Ac. 
The reduction of hypochlorous acid is rapid in aqueous acetic acid 
even when carefully shielded from light. From an aqueous solution 
of chloroamine it is possible to distil off hypochlorous acid under 
reduced pressure. Thus at 25° and under 13-9 mm. the first 50 cc. 
of distillate from 250 cc. of a 0-1 per cent. solution of a chloro- 
amine had a titre of 2-57 cc. of N/20 thio. No chlorine was found in the 
distillate, and there was no loss of chloroamine from the mother liquor 
other than by hydrolysis. The distillation of an equivalent solution of 
hypochlorous acid showed that the hydrolysis of the chloroamine is not 
extensive ; for the first 50 cc. gave a titre of 30 cc. N/20 thio. 
Reduction of the Chloroamine in Aqueous Solution—The behaviour of 
acetylchloroaminobenzene in pure water would be expected to show a 
marked difference from that in concentrated acetic acid media on several 
erounds. If it be granted that the mechanism of the isomeric transforma- 
tion consists in a reaction between chloroamine and hydrogen chloride, 
yielding anilide and chlorine, which then react to form the C-chloro- 
derivative, any extensive hydrolysis of the chlorine should lead to ab- 
normalities and retard the production of chloroanilides. Jakowkin‘ 
showed that the reversible hydrolysis of chlorine, which is governed by the 
equation K[Cl,]=[HCIO] [HCl], is very extensive in dilute aqueous 
solution. Thus, for example, over 90 per cent. of the chlorine at a con- 
centration of 0-05 per cent. and less is present as hypochlorous and 
hydrochloric acids. From the form of the equation it will be seen that 
the proportion of free chlorine in the system would rapidly increase as the 
concentration of hydrogen chloride was raised ; according to Jakowkin in 
solutions of hydrogen chloride above 0-1 N very little of the chlorine is 
present as hypochlorous acid. Above these limits of concentration of 
hydrogen chloride, therefore, the ordinary conversion of chloroamine 
would predominate. 
Our experimental study is generally in harmony with these anticipa- 
tions. With a high concentration of hydrogen chloride, the main reaction 
is a transformation of the chloroamine into monochloroacetanilides, but 
with low concentrations the reactions are greatly modified. In fact, the 
Poor with hydrogen chloride then closely resembles that with other 
acids, 
Aqueous solutions of acetylchloroaminobenzene change very slowly 
4 Zeit. f. Physik. Chem., 1899. 
