OF ARTS AND SCIENCES. 293 



In all the derivatives of tetrabromdinitrobenzol which were analyzed 

 it was found that only three of the atoms of broniiue had been at- 

 tacked. We had hoped to try some experiments at higher temperatures 

 for the purpose of replacing the fourth atom of bromine, but the work 

 described in this paper has taken so much time that we have been 

 unable to take up this branch of the subject. 



Bromdinitrotrianilidobenzol, C 6 Br(N0 2 ) 2 (C t; H 5 NH)g. 



To prepare this substance tetrabromdinitrobenzol was heated with 

 aniline in the proportion of one molecule of the former to a little more 

 than six of the base. Convenient amounts were 7 grs. of tetrabrom- 

 dinitrobenzol to 8.3 grs. of aniline. When the mixture was heated on 

 the water bath, the solid dissolved after some time, the solution being 

 accompanied by a change of color from yellow to bright red, and on 

 cooling the whole solidified to a mass of red needles; but in order to 

 get even a tolerable yield of the new substance the heating on the 

 water bath must be continued for at least four to six hours, and then 

 it is not by any means complete. A higher heat than the water bath 

 should not be used, as then the mixture shows a tendency to pass 

 into a purplish coloring matter, resembling impure rosaniline in ap- 

 pearance, and similar to the substance obtained in the same way from 

 tribromdinitrobenzol,* and like that undoubtedly produced by the 

 nitro groups taking part in the reaction. If the reaction had run 

 properly, the product consisted of a viscous or crystalline mass of the 

 color of red lead, from which in the first place the aniline bromide and 

 excess of aniline were removed by washing with water containing a 

 little hydrochloric acid, leaving a brick-red powder. The purification 

 was completed by crystallization from alcohol, and afterward from a 

 mixture of alcohol and chloroform, until it showed the constant melt- 

 ing point 175°-176°. If there was difficulty in obtaining crystals of 

 the proper melting point, it was found advisable to warm the substance 

 again with aniline for two or more hours, and then purify again in the 

 manner just described. In addition to unaltered tetrabromdinitroben- 

 zol a small amount of an impurity was found, which melted in the 

 crude state between 120° and 140°, but we did not succeed in isolat- 

 ing a substance fit for analysis from it. The main product, when 

 pure, was dried at 100°, and analyzed with the following results : — 



I. 0.1667 gr. of the substance gave 20.4 c.c. of nitrogen at a tem- 

 perature of 25° and a pressure of 768.4 mm. 



* These Proceedings, xxiii. 145. 



