OF ARTS AND SCIENCES. 257 



refer the reader to a paper " On the Action of Sodium Malouic Ester 

 on Tribromdiuitrobenzol " by .one of us and W. S. Robinson.* 



The results described in this paper can be briefly stated as follows. 

 Sodium malonic ester forms in the cold with tribromtriuitrobenzol 

 bromtrluitrophenylmalonic ester, 



CeHBr(NO,)3CH(COOaH5)„, melting point 104°-105°, 



which has acid properties forming salts even with aqueous solutions 

 of the alkaline carbonates. Of these the red soluble sodium salt has 

 been studied, and its analysis led to the formula 



CeHBr(N02)3CNa(COOC2H.)2. 



The yellow insoluble copper salt, on the other hand, gave no con- 

 stant result on analysis, but on several occasions, in trying to make 

 it from a solution of cupric chloride in alcohol and the sodium salt, a 

 crystalline substance free from copper was obtained melting in the 

 neighborhood of 75°. Unfortunately the end of the term has pre- 

 vented us from studying t])is substance, which is the more interesting 

 because no similar comjjound has been obtained from the con-espond- 

 ing dinitro body. 



The reactions by which the broratrinitrophenylmalonic ester is 

 derived from tribromtriuitrobenzol have been made out as follows : — 



C6Br.(N0.,), + 3 CHNa(C00C,H.)2 = 



NaBr + CcBr,(NO.)3CH(CObC2H,)2 + 2 CHNaCCOOC^H,)^ = 

 C6Br2(N02)3CNa(c60C2H,), + CH2(COOC2H,)2 



" + CHNalCOOC^H,), + NaBr = 

 C6HBr(NO,)3CNa(COOaH5), + CHBr(COOC2H.)"2 



+ CHNaCCOOCoH^), + NaBr=z 

 C6HBr(N02)3CNa(COOC,H5), + 2NaBr + C2H2(COOC,H,X. 



The acetylentetracarbonic ester formed according to the last re- 

 action was obtained from the oily secondary product of the action by 

 distillation under diminished pressure, and identified by its melting 

 point and analysis. 



Perhaps the most striking difference between the dinitro and trini- 

 tro compounds consisted in the fact that the trinitro ester, or its salts, 

 when heated with an excess of common strong nitric acid, turned 

 bright blood-red, whereas no such action could be obtained from the 

 dinitro compound. The red product, on crystallization from alcohol, 



* Tliese Proceedings, xxiv. 1. 



VOL. XXIV. (n. S. XVI.) 17 



