232 PROCEEDINGS OF THE AMERICAN ACADEMY. 



In the hope of finding an easier method for making this dibromtrinitro- 

 benzol the action of dibromdinitrobenzol (Brg 1.3. (N02)2 4 . 6) with 

 nitric and sulphuric acids was studied. This gave the desired dibromtrini- 

 trobenzol, but the product was mixed with so Large a proportion of tribrom- 

 dinitrobenzol that the method was not adapted to the preparation of the 

 substance. This tribroradinitrobenzol is a new substance, melting at 150°. 

 There can be no doubt that its constitution is Brg 1 .2.3. (N02)2 4 . 6, 

 since it is made by introducing a third atom of bromine into the dibrom- 

 dinitrobenzol Br2 1.3. (N02)2 4 • 6, and, if this occupied the only other 

 vacant place (5), the jDroduct would be the common tribromdinitro- 

 benzol, which melts at 192°. The formation of this tribromdinitrobenzol 

 during this reaction is strictly according to the analogy of the behavior 

 of the tribromdinitrobenzol, which, when boiled with a mixture of fum- 

 ing nitric and sulphuric acids^ gives rise to tribromtrinitrobenzol and 

 tetrabromdinitrobenzol. * 



As neither of the new substances just described can be prepared easily 

 on a large scale, we have confined our work on them to the study of the 

 principal action of sodic ethylate on each. This reaction runs in a nor- 

 mal way, giving styphnic diethylether, 



C6H(N02)3(OC2H5)2, ( (OC2H5)2 1 • 3 . (N02)3 2 .4.6), 



with dibromtrinitrobenzol, recognized by its melting point 121° ; and 

 with tribromdinitrobenzol a new bromdinitroresorcine monoethylether 

 melting at 78°. The subject did not promise to be of sufficient interest 

 to make it worth while to study the secondary products of these reactions. 



EXPEKIMENTAL PaKT. 



Action of Sodic Sulphite in Alcoholic Solution on Trihromdinitrohemol. 



Five grams of symmetrical tribromdinitrobenzol (Brg 1.3.5. (N02)2 

 2 . 4) were dissolved in 70 c.c. of alcohol mixed with 20 c.c. of benzol, 

 five grams of normal sodic sulphite added, and the mixture boiled for five 

 hours in a flask with a return condenser. The red liquid thus obtained 

 was filtered from the insoluble portion, evaporated to dryness, and the 

 residue washed with water, until the yellow color was removed. The 

 part insoluble in water was then recrystallized from alcohol with the aid 

 of bone-black, until it showed the constant melting point 117°. This 

 melting point indicated that it was Koerner's dibromdinitrobenzol f 



* Jackson and Wing, Tliese Proceedings, XXII. 139 

 t Gazz. Cliim., 1874, 305. 



