156 



Dr. K J. P. Orton. 



[Dec. 1, 



oxide) being formed. In diazotising in the presence of hydrogen 

 chloride, an ortho-nitro group is replaced by chlorine.] 



The isomeric changes of the diazonium salts differ, however, some- 

 what from the similar changes of the phenylacylchloramines, phenyl- 

 nitramines, &c. The latter compounds are per se relatively stable, 

 .and apparently only undergo change in the presence of some agent 

 (catalyst) ; the diazonium compounds, on the other hand, appear to be 

 intrinsically labile, and in aqueous solution, at least, capable of passing 

 into a more stable configuration. In the latter case the nitrogen atom, 

 bearing the wandering group, the hydroxyl group (or, as in Hantzsch's 

 instances, the chlorine atom or the thiocyanate group), is pentad, 

 thus, Ph.N(OH):N, whilst in the phenylacylchloramines, &c, it is 

 triad. The idea at once suggests itself that in the case of the last- 

 mentioned compounds, the first action of the catylist is to form an 

 additive product, in which the nitrogen is pentad. The product, in 

 which, it should be noted, more than one negative radicle is attached 

 to the nitrogen, is not a stable compound, and is now capable of 

 passing into the isomeric quinone form, and thus start the transforma- 

 tion. 



These results are also of interest, inasmuch as Hantzsch* has 

 stated recently that he has obtained s-tribromophenylnitrosamine, 

 •C6HoBr3.NH.NO, by adding sodium acetate to a solution of a s-tri- 

 bromobenzenediazonium salt. He describes it as a bright yellow 

 amorphous substance, which decomposes at 85°. As far as can be 

 judged, it is this very reaction which has been studied in the course of 

 the author's experiments. The substance which is precipitated is at 

 first glance a yellow amorphous powder, but close observation shows 

 that long (J — 1 cm.) orange crystals are present. These crystals are 

 the 3 : 5-dibromo-o-diazophenol hereafter described. The powder is 

 probably a hydroxyazo-condensation product. Hantzsch does not 

 appear to have observed that bromine is eliminated. He also affirms 

 (loc. cit.) that he obtained the nitrosamine by the cautious addition of 

 acetic (or other) acid to the alkali diazotate ; in the writer's experience, 

 however, this always leads to the elimination of halogen. 



The Transformation of s-Trichlorobenzenediazonium Hydroxide. 



s-Trichlorobenzenediazonium hydrogen sulphate, C<jH.2Cl3.N(S04H) IN, 

 is very easily prepared by diazotising, by means of amyl nitrite, 

 s-trichloraniline dissolved (or suspended) in glacial acetic acid contain- 

 ing sulphuric acid. The salt is precipitated by ether, and is purified 

 by dissolving in methyl alcohol ; on adding ether to this solution 

 the sulphate separates in small colourless lustrous prisms, often forming 



* ' Berichte, 5 1902, vol. 35, p. 2964. 



