OP ARTS AND SCIENCES. 283 



the tribromnitroresorcine diethylether removes from it two atoms 

 of bromine which are replaced by hydrogen, so that the product is 

 bromnitroresorcine diethylether, C 6 H 2 BrN0 2 (OC 2 H 5 )o, melting at 

 115°; — an observation which will be of value in discovering the 

 cause of the strange replacements of bromine by hydrogen so often 

 found in the course of this work. 



PART I. 

 Action of Sodic Ethtlate on Tribromtrinitrobenzol. 



In our earlier paper * on this subject we showed that sodic ethyl- 

 ate brought about a replacement of two of the nitro groups in 

 tribromtrinitrobenzol by two ethoxy radicals forming tribromnitro- 

 resorcine diethylether, C 6 Br 3 ]Sr0 2 (OC 2 H 5 ) 2 , as the principal product 

 if alcohol was used as the only solvent and the mixture carefully 

 cooled. There remained, however, several points which needed 

 more careful examination, especially the effect upon the reaction of 

 differences of temperature, the effect of using different solvents, 

 and the source of the sodic bromide which was always formed in 

 addition to the sodic nitrite. The results of our work on these 

 subjects are given in the following paragraphs. 



The experiments described in our first paper had led us to think 

 that the tribromnitroresorcine diethylether was formed only when 

 the mixture of tribromtrinitrobenzol and sodic ethylate was care- 

 fully cooled. To test the accuracy of this conclusion, we dissolved 

 some tribromtrinitrobenzol in alcohol and a little benzol with the 

 aid of heat, and added to the boiling solution in small quantities at 

 a time enough sodic ethylate to give three molecules of the ethylate 

 to each molecule of tribromtrinitrobenzol. As soon as all the 

 ethylate had been added, the bright scarlet solution was allowed to 

 cool, and then evaporated spontaneously. The aqueous washings 

 of the residue gave a strong test for a nitrite, and also for a bro- 

 mide. The portion insoluble in water was purified b} r crystalli- 

 zation from alcohol until it showed a melting point of 100° (the 

 tribromnitroresorcine diethylether melts at 101°), when it was 

 analyzed with the following result : — 



0.2076 gr. of the substance gave by the method of Carius 

 0.2601 gr. of argentic bromide. 



* These Proceedings, XXV. 183. 



