CONTRIBUTIONS FROM THE CHEMICAL LABORATORY OF 



HARVARD COLLEGE. 



ON THE ACTION OF SODIC SULPHITE ON TRIBROM- 

 DINITROBENZOL AND TRIBROMTRINITROBENZOL. 



By C. Loring Jackson and Richard B. Earle. 



Presented May 9, 1900. Received October 17, 1900. 



In the course of an extended study of the action of various reagents on 

 tribromdinitrobenzol (Brg 1.3.5. (NOo)^ 2.4.) it became of interest to 

 determine whether this substance could be converted into a sulpho-acid 

 by the method of Strecker,* that is, boiling the halogen compound with 

 an aqueous solution of normal sodic sulphite, and experiments in this 

 direction were tried rather early in the work, with negative results. 

 Upon returning to the subject later we did not find any conditions under 

 which an aqueous solution of sodic sulphite acted on tribromdinitrobenzol. 

 but when we substituted alcohol for water as the solvent, we obtained a 

 reaction. This, however, took a different direction from that which we 

 had expected, as under these conditions the sodic sulphite acts as a re- 

 ducing agent, converting the tribromdinitrobenzol into dibromdiuitro- 

 benzol by replacing one of the atoms of bromine by hydrogen. The 

 atom of bromine replaced is the one between the two nitro groups, since 

 the dibromdinitrobenzol formed melted at 117°, which is the meltino- 

 point of the dibromdinitrobenzol t Br2l.3.(N02).24.6. That the product 

 had this constitution was confirmed by its conversion into the bromani- 

 lidodiuitrobenzol, which showed the melting point 157°. t Tiibromtri- 

 uitrobenzol undergoes a similar reduction with an alcoholic solution of 

 normal sodic sulphite, the product being dibromtrinitrobenzol, which can 

 have only this constitution : Br^ 1.3. (N0.2)3 2.4.6. It is a new sub- 

 stance, and melts at 135°. 



* Ann. Chem. (Liebig), CXLVIII. 90. 



t Koerner, Gazz. Chim., 1874, 305. 



t Jackson and Cohoe, These Proceedings, XXXVI. 75. 



