Ryan and O'Riokdan — Action of Bromine on Diphenylamine. 221 



in small quantities, to a solution of -4 grams of bromine in 25 c.c. of chloro- 

 form, with constant shaking. Fumes of hydrohromic acid were copiously 

 evolved. The flask containing the mixture was then placed on a white 

 surface in bright sunlight for about six hours. At first felted needles 

 (probably tetrabromo-diphenylamine) separated; but these dissolved on 

 standing, forming a clear solution. After allowing the solution to remain in 

 the sunlight it was let stand overnight. In the morning white crystals had 

 separated, and the solution on evaporation yielded a further quantity of this 

 substance in a slightly impure condition; altogether 2T grams — a yield of 

 approximately 70 per cent.— was obtained. It is soluble in benzene and 

 chloroform, and slightly soluble in alcohol. 



A determination of bromine in the compound by Stepanow's method gave 

 the following result : — 



- 2036 gram of the substance on treatment with sodium and alcohol gave 

 an amount of. sodium bromide which required 18-91 c.c. of N/10 silver 

 nitrate for complete precipitation, 



corresponding to Br 74'o 



C 12 H,Br 6 NH requires Br 74" 6 



The compound is, therefore, a hexabromo-diphenylamine ; and it is 

 probably identical with the hexabromo-diphenylamine (m, p. 218° C.) 

 obtained lay Gnehni (Ber. d. Dtsch. Chem. Ges. VIII, 1875, p. 926) by the 

 bromination of diphenylamine in acetic acid solution. 



The yellow substance melting about 175° C. was found, on recrystallisa- 

 tion a few times from chloroform, to melt at 186-187° C. The melting-point 

 of tetrabromo-diphenylamine (188° C). was not appreciably lowered by 

 mixing some of this substance with the tetrabromo compound. The two 

 substances are, therefore, identical ; the yellow colour of the compound here 

 mentioned being probably due to the presence of a small amount of some 

 other substance which we did not, however, isolate. 



This substance, which is slightly impure tetrabromo-diphenylamine, was 

 almost the only product obtained when the bromination was carried out by 

 adding the bromine solution as before, allowing the mixture to stand for half 

 an hour in sunlight, and isolating the product by the method described 

 above. In this way discoloured, flaky, acicular crystals were obtained which, 

 after recrystallisation, were pale-yellow in colour, and melted at L87"5 I '. 



II. Action of Bromine on Tetrabromo-Diphenylamine. 



Tetrabromo-diphenylamine was first prepared by addition of the theore- 

 tical quantity of bromine in chloroform solution to a chloroform solution of 



[2G2] 



