JACKSON AND EARLE. — TRIBROMTRINITROBENZOL. 235 



into dibroiuacetanilid, — the monobromacetanilid was mixed with enough 

 glacial acetic acid to convert it into a semi-liquid mass, to which the cal- 

 culated amount of bromine was added from a burette. It was then 

 warmed on the steam-bath, until it was transformed into a clear, 

 dark-red liquid, which was poured into water, filtered, and the pre- 

 cipitate ground in a mortar with a solution of sodic hydrate to remove 

 the excess of bromine. The dibromdinitrobenzol used for our work was 

 recrystallized until it showed the correct melting point 117°. 



To convert the dibromdinitrobenzol into dibromtrinitrobeuzol we pro- 

 ceeded as follows. Twenty grams of dibromdinitrobenzol were added to 

 500 c.c. of fuming nitric acid of specific gravity 1.50 and 200 c.c. of 

 sulphuric acid of specific gravity 1.86, aud the mixture was boiled 

 violently for about three hours in a flask closed with a porcelain 

 crucible. Toward the close of the operation a reddish oil separated, 

 after which the process was continued only so long as the liquid 

 boiled freely, since decomposition and darkening of the color resulted 

 from too long continued boiling. After the mixture had been boiled 

 for a sufficiently long time, it was allowed to cool, poured into ice water, 

 and filtered. The precipitate was recrystallized from a mixture of 

 alcohol and benzol, until it showed a constant melting point, but, as 

 this stood at 150°, the substance was not the expected dibromtrinitro- 

 benzol, which melts at 135°. On examining the mother liquors from 

 this substance, however, we found the dibromtrinitrobeuzol, which, after 

 purification by crystallization from a mixture of benzol and ligroin, was 

 recognized by its melting point 135°, and the following analysis of the 

 substance dried at 100° : — 



0.2174 gram of the substance gave by the method of Carius 0.2203 

 gram of argentic bromide. 



C 6 HBr„(N0 2 ) 3 . 



Bromine 43.10 43.10 



The dibromtrinitrobenzol is therefore formed by this process, but so 

 much of the other product melting at 150° is formed at the same 

 time that this is not a convenient method of preparing it, and the 

 dibromtrinitrobenzol remains a not easily accessible substance. 



Tribromdinitrobenzol, C 6 HBr 3 (N0 2 ) 2 . (Br, 1. 2. 3. (N0 2 ) 2 4. 6.). 



The substance melting at 150°, prepared by the action of nitric acid 

 and sulphuric acid on dibromdinitrobenzol as described in the preceding 

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



