280 PROCEEDINGS OP THE AMERICAN ACADEMY 



IT. 0.2056 gr. of the salt gave 0.0407 gr. of sodic sulphate. 

 III. 0.2531 gr. of the salt gave 0.0390 gr. of sodic sulphate. 



Sodium 



It is evident from these results that the method of preparation is 

 unsatisfactory, and we ascribe this to the action of the sodic hydrate 

 (or ethylate) on the bromine, and perhaps also on the acetacetic radi- 

 cal, as, when these two sources of error were removed by using the 

 auilidodinitrobenzylmethylketone, an excellent result was obtaineii. 

 Bad as these analytical results are, they show that the salt contains 

 but one atom of sodium, and therefore must have the formula which 

 we have ascribed to it. 



Properties. — The sodium salt of the bromdinitrophenylacetaceiic 

 ester forms a brick-red amorphous mass, easily soluble in water, al- 

 cohol, or ether, but insoluble in benzol. Much less freely soluble in 

 a solution of sodic hydrate than in water. Strong nitric acid decom- 

 poses it, giving apparently the unaltered ester. 



BromdinitrobenzylmethyJketone (^Bromdinitrophenylacetone), 

 C,H2Br(NO,),CH2COCH„. 



This substance can be made from the bromdinitrophenylacetacetic 

 ester by the action of dilute sulphuric acid in open vessels, or of strong 

 iiydrochloric acid in sealed tubes. The method of preparation which 

 gave us the best results was as follows : 2 to 2,5 grs. of bromdinitro- 

 phenylacetacetic ester were boiled with about 200 c.c. of sulphuric 

 acid of specific gravity 1.44, boiling point 132°, in a flask with a 

 return condenser, until all the solid was dissolved, which took usually 

 from one hour to an hour and a half. The yellow solution was then 

 allowed to cool, when it deposited a heavy white flocculent precipitate, 

 which was increased in quantity by diluting largely with water; it 

 was filtered out, and after thorough washing with water was purified 

 by crystallization from alcohol until it showed the constant melting 

 point 112°-113°, when it was dried at 100° for analysis. If the ester 

 used in this process was not perfectly pure, a tarry impurity was 

 formed which could be removed only with great difficulty ; the best 

 plan in such a case was to wash the product with a small quantity 

 (20-30 c.c.) of benzol, which dissolved the ketone more readily than 

 its impurity, but even after this treatment tedious crystallization from 

 alcohol was necessary to obtain a pure substance. 



