110 PROCEEDINGS OF THE AMERICAN ACADEMY. 



Calculated for 

 [C6H2(N02)3C(COOC2Hj)2]2Cu. Pound. 



Copper 7.92 7.72 



Properties. — The copper salt is a brownish red powder, essentially 

 insoluble in water, it resembles the barium and zinc salts in being very 

 hygroscopic, and exploding easily, when heated with strong sulphuric 

 acid. 



Action of Nitric Acid on Trinitrophenylmalonic Ester. 



The action of nitric acid upon this substance is similar to its action with 

 the broratrinitrophenylmalonic ester,* that is, the nitrite or the substituted 

 tartronic ester is obtained according to the length of the treatment. 



Nitrite of Trinitrophenylmalonic Ester, 

 C6H2(N02)3CONO(COOC2H5)2. 



Two grams of the trinitrophenylmalonic ester were heated on the 

 steam bath with about 15 c.c. of common strong nitric acid. After three 

 minutes the ester had melted to a clear red oily globide, and the entire 

 liquid had taken on a reddish color. If the process was continued for 

 two minutes more, the globule went into solution. The heating should 

 not be continued beyond this point ; in fact, it can be stopped to advan- 

 tage even as soon as the globule of the melted substance is formed. If 

 all the organic matter had gone into solution, reddish crystals separated 

 in large quantity, as the liquid cooled, which were purified by washing 

 with water and several crystallizations from alcohol, until they showed 

 the constant melting point 109°. The globule, if the process was stopped 

 before it disappeared, was allowed to solidify, and then purified in the 

 same way. The substance was dried in vacuo, and analyzed with the 

 following result : — 



0.2190 gram of the substance gave 25.8 c.c. of nitrogen, at a tempera- 

 ture of 20° and a pressure of 760.8 mm. 



Calculated for 

 C6H2(N02)3CN0o(C00C2H5)2. Found. 



Nitrogen ' 13.46 13.46 



Properties of the Nitrite of Trinitrophenylmalonic Ester. 



It crystallizes in long flat white prisms, apparently belonging to the 

 monoclinic system, usually terminated by two planes at an obtuse angle to 

 each other, but sometimes only by a single plane. It melts at 109° with 



* These Proceedings, XXVI. 72. 



