268 PROCEEDINGS OP THE AMERICAN ACADEMY 



Action of Sulphuric Acid. — Constitution of the Bromtrinitrophenyl- 



malonic Ester. 



The action of dilute sulphuric acid upon the bromtrinitrophenyl- 

 malonic ester was studied in the hope of obtaining the as yet un- 

 known bromtriuitrophenylacetic acid, as it had been found by one of 

 us and W, S. Robinson f that the corresponding dinitro compound was 

 decomposed in this way. For this purpose, about 2 grs. of the ester 

 were boiled in a flask under a return condenser with sulphuric acid of 

 specific gravity 1.44 and boiling point 132° until the ester had dis- 

 solved ; the liquid was then allowed to cool, when it deposited crystals, 

 which, after recrystallization from alcohol, were recognized by their 

 melting point 143°-144°, their appearance, and the absence of acid 

 properties, as the metabromtrinitrotoluol discovered in this laboratory 

 by Bentley and Warren. 



It is evident therefore that the bromtrinitrophenylacetic acid is less 

 stable than the corresponding dinitro compound, as indeed was to be 

 expected, and was broken up as soon as formed into the substituted 

 toluol and carbonic dioxide according to the following reaction : 



C G HBr(N0 2 ) 3 CH 2 COOH = C 6 HBr(N0 2 ) 3 CH 3 + CO,. 



The formation of this substance would settle the constitution of 

 the bromtrinitrophenylmalonic ester, if that were necessary, but 

 the preparation of the ester from symmetrical tribromtrinitrobenzol 

 leaves no doubt as to its constitution, which must be as follows, 

 CH(COOaH-).,, N0 2 , Br, NO,, H, NO,, I, 2, 3, 4, 5, 6, and Bentley 

 and Warren have established the corresponding constitution for their 

 substituted toluol. 



Trinitrophernjlendimalonic Ester, C c H(N0 2 ),[CH (COOC 2 H 5 ),] 2 . 



This substance was formed by the further action of sodium malonic 

 ester on bromtrinitrophenylmalonic ester. For this purpose, 1 gr. 

 of bromtrinitrophenylmalonic ester dissolved in ether was mixed with 

 1.5 grs. of malonic ester previously converted into sodium malonic 

 ester and dissolved in much absolute alcohol, and the mixture boiled 

 in a flask with a return condenser for an hour. The product, which 

 was very dark brown, almost black, was treated with water, acidified 

 with dilute sulphuric acid avoiding a large excess, the ether removed 

 with a drop funnel, and the aqueous liquid shaken out twice with 

 ether. The extract, after distilling off the ether and allowing it to 



t These Proceedings, xxiv. 240. 



