OF ARTS AND SCIENCES. 



93 



Nitrite of Bromdinitrophenylmalonic Ester, 

 CaIl2Br(N02)oCN02(COOC2lIii)o. 



Although bromdinitrophenylmalonic ester does not change in color 

 when heated with nitric acid, as has been stated more than once in 

 previous papers* from this Laboratory, it really is affected in the same 

 way as the corresponding trinitro compound, being converted into its 

 nitrite, but without the formation of the i-ed secondary product which 

 made the reaction so striking in that case. The substance was pre- 

 pared as follows. A small quantity of the bromdinitrophenylmalonic 

 ester (melting point 75° -76°) was heated on the steam bath with nitric 

 acid of specific gravity 1.38 for five minutes, or longer (as the same 

 compound was obtained if the heating was continued three hours) ; 

 there was at first no sign of a reaction except a slight evolution of 

 nitrous fumes ; but, as the heating continued, the undissolved solid 

 melted, forming an oil drop, which after cooling solidified to a mass of 

 crystals, while at the same time the acid liquid deposited crystals look- 

 ing very much like those of the bromtrinitrophenyltartronic ester. 

 All of these crystals were purified by recrystallization from boiling 

 alcohol, until they showed the constant melting point 111°, when they 

 were dried at about 70°, and analyzed with the following results : — 



I. 0.1973 gr, of the substance gave on combustion 0.2492 gr. of 



carbonic dioxide and 0,0510 gr. of water. 

 11. 0.2084 gr. of the substance gave 17.4 c. c. of nitrogen at a tem- 

 perature of 22° and a pressure of 755.6 mm. 



Calculated for Found 



C6H,,Br(NO„)2CNOo(C02C2Hi;)2. I. II. 



Carbon 34.66 34.44 



Hydrogen 2.67 2.87 



Nitrogen 



9.33 



9.41 



The substance therefore is the nitrite of the bromdinitrophenyl- 

 malonic ester, and not the corresponding tartronic ester, as we had 

 expected from the long heating used in one of the methods of 

 preparation, and from the fact that no difficulty was encountered in 

 making the combustion of it. 



Properties^ — The nitrite of bromdinitrophenylmalonic ester crys- 

 tallizes usually in thick rhombic crystal often one miUimeter m each 

 direction, which look somewhat like rhombohedra with a sharp acute 

 angle, but are seen to be twins by the lines of twinning and stria- 



* These Proceedings, XXIV. 6, 257. 



