( 682 ) 



If, on account of the analogy between phenjl-chloroamine and 

 acetylchloi'ophenylamine, we assume that in the case of tiie first sub- 

 stance the velocity of the conversion into o- and ^>-chloroaniline is 

 also strongly accelerated by elevation of temperature and addition 

 of hydrochloric acid, the conditions for obtaining chloroaniline instead 

 of aniline, in the reduction of nitrobenzene with tin and hydrochloric 

 acid, are as follows : 



1. Slow reduction, or addition of tin in small quantities at the 

 time, in order not to at once reduce the phenylhydroxylamine to 

 aniline. 



2. Excess of hydrochloric acid so as to rapidly convert the phenyl- 

 chloroamine formed into chloroaniline. 



3. The reaction should take place at the boiling temperature, as 

 elevation of temperature also promotes this conversion. 



The experiment was now conducted as follows: 



10 cc. of nitrobenzene were dissolved in 100 cc. of alcohol and 

 200 cc. of 25 V„ hydrochloric acid were added. This solution was 

 boiled over the naked tlame, whilst 15 grams of tin were added 

 through the retlux condenser in small portions. Each time, after 

 adding a small amount of tin, the boiling was continued until every- 

 thing had dissolved before adding a fresh portion. The experiment 

 lasted six hours. The unaltered nitrobenzene was now removed by 

 steam, the residue was rendered alkaline and the aniline and chloro- 

 aniline recovered by distillation in steam. 



In this way, 6.5 gram of oil were obtained. The greater portion 

 of this oil was distilled between 182° and 225°, the residue solidified 

 in the distilling tlask, and proved to be jj-ohloroaniline (m. p. 70"). 

 The oil consisted of aniline and o- and />chloroaniline. 



From a chlorine determination according to Carius, it appeared 

 that the mixture consisted of 55% of chloroaniline and 457„ of aniline. 



If the reduction experiment was made with SnCl, and HCl {o-\-p) 

 chloroaniline (537J were formed together with aniline. In this case, 

 the stannous chloride was also added in small portions, so as to 

 give the intermediary formed phenylhydroxylamine an opportunity 

 of being converted into o- and ^^chloroaniline. Nitroso-benzene gives 

 the same result '). 



In the same manner, the reduction of nitrobenzene with tin and 

 hydrobromic gave a mixture of aniline and {o- and ^j)-bromoaniline. 



At present it is still ditTicult to predict which aromatic nitro- 



') Cf. GoLDsciiMiDT, Zfitschfiri liii- I'liys. Clliem: 48, 435. 



