104 REPORT—1905, 
little studied. It was thought that some light might be thrown on the 
mechanism of the change by studying the behaviour of s-trisubstituted 
nitroamines in which it is impossible for the nitro group to wander to the 
ortho or para position without displacing the atom or group already 
attached at that point to the nucleus. Such s-trisubstituted nitroamines 
can now be easily prepared,! and those in which chlorine or bromine 
occupy the 2 : 4 : 6 positions were selected for investigation. 
It was ascertained that when subjected to conditions (treatment with 
sulphuric acid in acetic acid solution) which lead to the isomeric change of 
unsubstituted nitroamines :— 
(i) A series of colour changes occur indistinguishable from those given 
by the unsubstituted nitroamines whilst they are undergoing the isomeric 
change ; 
(ii) Bromine, in the para position, is partially replaced by the nitro 
group, a substituted p-nitroaniline being formed ; 
(iii) If chlorine occupied the para position, no replacement occurs, 
but the final product is a quinone derivative. In the case of s-trichloro- 
aniline, hexachlorophenyliminoquinone is produced ; and 
(iv) The nitro group never passes into the meta position.” 
II. The Euchange of Halogen for Hydroxyl in Benzenediazonium 
Hydroxides. 
The conversion of s-trihalogenbenzenediazo-compounds, s-trichloro- 
and s-tribromo-diazobenzene, into the corresponding dihalogen-o-quinone- 
diazides may be regarded, at least in one of its stages, as an isomeric 
change ; the ionic hydroxyl (OH): of the diazonium hydroxide takes the 
place of the bromine in the ortho or para position, but not in the meta 
position, the bromine becoming ionic, Br-.’ 
The transformation of s-tribromodiazobenzene has been more fully 
studied, in order to ascertain whether any appreciable quantity of nitroso- 
amine, C;,H,Br;.NH.NO, was also formed simultaneously from the diazo- 
hydroxide. It was ascertained that the replacement of halogen by 
hydroxyl was always the main reaction, and depended little on tempera- 
ture, between the freezing-point and 15°, The nitrosoamine, if formed, is 
present in such small amount as not to be capable of certain recognition 
by means of the /3-naphthol derivative.* 
III. Influence of Light on Diazo-Reactions. 
A very interesting action of light on solutions of diazonium salts, 
which hitherto appears to have escaped notice, has been observed.> The 
aqueous, alcoholic (methyl! or ethyl), or acetic acid solutions of diazonium 
salts are sensitive to light. On exposure nitrogen is evolved, the acid 
radical appears as free acid, and the phenol, its methyl or ether, or its 
acetate, according to the nature of the solvent, is formed. Many diazonium 
4 Orton, Zrans. Chem. Soc., 81, 806. 
2 Trans. Chem. Soc., 87, 389. 
3 Proc. Roy. Soc., 11, 153; Trans. Chem. Soc.. 88, 796. 
4 Trans. Chem. Soc., 87, 99. 
* Proc. Chem. Soe., 1905, 21, 168. 
