1()0 REPOKTS ON THE STATE OF SCIENCE. 



In the formation of the hexachlorophenyliminoquinoni3, 



CI CI CI 



0:<J:\:N.<~>C1, 



CI CI 



from s-trichloronitroamiuobenzene, a chlorine, atom must, ib iS clear, h^ 

 transferred from one carbon atom of the benzene ring to the neighbouring 

 carbon atom. In the case of the s-tribromonitroaminobenzene, on the 

 other hand, it would appear that the detached bromine atom only 

 partly recombines with the neighbouring carbon ; hence a mixture of 

 phenyliminoquinones is formed. 



Reaction of Phenyliminoqidnones ivith Ilydroijen Chloride. — The 

 phenyliminoquinones interact with hydrogen chloride in a very interesting 

 way, forming a chlorohydroxydiphenylamine, thus : 



0:<('" '\;N<^ ^ + HC1-»H0<^ \ NCI i(^ \ -4 



CI 



An additive product, a chloroamino derivative, is possibly first formed, 

 which then passes into a diphenylamine, the chlorine wandering into one 

 of the nuclei, and taking up an ortho or para position with respect to 

 the nitrogen atom. 



This interpretation of the change is strengthened by the fact that 

 hexachlorophenyliminoquinone does not react with hydrogen chloride in 

 this way ; every position into which the chlorine atom could pass from 

 the nitrogen is already occupied by chlorine. 



II. The Exchange of Halogen for Hydroxyl in Senzenediazonium 



Hydroxides. 



The displacement of halogen by hydroxyl in halogenbenzenediazo- 

 compounds has been studied with substances containing methyl groups, 

 such as the diazotoluenes and diazoxylene. The presence of the methyl 

 group greatly retards the replacement of halogen when the diazonium 

 .salts of weak acids are used. In dilute aqueous solution neither bromo- 

 7/i-xyleuediazonium acetate nor bicarbonate lose bromine ; 3 : 5-dibromo- 

 4-toluenediazonium acetate decomposes very slowly, but the bicarbonate, 

 in the rapidity of its decomposition, approaches the trihalogenbenzene- 

 diazonium bicarbonates. Weighting the benzene nucleus with negative 

 groups restores this property ; thus 2-nitro-3 : 5-dibromo-4-diazotoluene 

 or 2:4: 6-tribromo-3-diazotoluene lose bromine lapidly in dilute-acetic 

 acid solution. 



These facts are in accord with the views previously expressed ^ ; the 

 bromine is displaced by ionic hydroxyl, (OH)', which is produced in the 

 hydrolytic dissociation of the salts of weak acids. The strong diazonium 

 bases derived from toluene and xylene form acetates Avhich suffer hydro- 

 lytic dissociation to a less extent than the halogenbenzenediazonium salts. 



Chlorobromobenzenediazo-Compounds. — Mixed halogenbenzenediazo- 

 compounds, containing both chlorine and bromine, have been investigated 

 Avith the object of comparing chlorine with bromine as regards their dis- 



' Trans. Chem. Soc, 83, 700. 



