222 SCIENCE PROGRESS 



A similar change takes place in the case of dibromo-o-nitrophenol 



OH 



Br^NO, 



OH 

 Brr^Br 



Br NO, 



Dibromo-o-nitrophenol Dibromo-/>-nitrophenol 



and apparently also in the dibromo-o- and />-nitranilines when 

 acted on by concentrated hydrochloric or sulphuric acid. 1 



NO.. 



The interchange does not occur, however, in the correspond- 

 ing chlorine compounds nor when the hydrogen of the 

 phenol is displaced by an alkyl group. 



Somewhat similar conditions attend the conversion of the 

 nitroamines into nitranilines, e.g. 



Orton and Reed have shown 2 that the colourless nitro- 

 amine can be converted into the yellow nitraniline, not only 

 by the action of nitric acid, but also by that of hydrogen 

 chloride, hydrogen bromide, chlorine and bromine, when these 

 reagents are applied in the gaseous form to crystals of the 

 nitroamine enclosed in a sealed tube with phosphoric anhy- 

 dride; iodine, sulphur dioxide, carbon dioxide and methyl 

 iodide had no action on the nitroamine. The mechanism of 

 this action is in part elucidated by the discovery that a colour- 

 less compound of the nitroamine with a molecular proportion 

 of hydrogen chloride can be precipitated by passing the dry 

 gas into a solution of the amine in light petroleum ; this 

 compound is resolved by alkalis into the nitroamine and 



1 Orton and Pearson, Trans. Chem. Soc. 1908, 93, 725. 



2 British Assoc. Report, Leicester, 1907. 



