242 PROCEEDINGS OF THE AMERICAN ACADEMY 



II. 0.1933 gr. of the substance gave 15.6 c.c. of nitrogen at a tem- 

 perature of 15°. 5, and a pressure of 759.2 mm. 

 III. 0.1821 gr. of the substance gave, according to the method of 

 Carius, 0.1152 gr. of argentic bromide. 



III. 



26.93 



These analyses supersede those already published,* which were 

 made with a substance prepared by crystallization from dilute alcohol, 

 before we had found that this solvent decomposed the compound ; it 

 was therefore decidedly impure, as indeed was shown by its melting 

 point, which was 170° instead of 177°. 



The yield of the bromdinitrophenylacetic acid is essentially quanti- 

 tative, as 2 grs. of the bromdinitrophenylmalonic ester gave, after 

 treatment with dilute sulphuric acid, 1.4 grs. of bromdinitrophenylacetic 

 acid melting at 177°, instead of the calculated amount, 1.56 grs., that 

 is, 90 per cent of the theory; the missing 10 per cent without doubt 

 remained dissolved in the dilute sulphuric acid, in which the substi- 

 tuted acetic acid is not wholly insoluble, as the 1.4 grs. were obtained 

 by simple filtration, no attempt being made to recover the organic 

 substance from the filtrate. 



In view of the observations described above, there can be no doubt 

 that the following reactions take place when bromdinitrophenylmalonic 

 ester is saponified by heating it with hydrochloric acid at temperatures 

 in the neighborhood of 145° : 



.C6H2Br(NO,),CH(COOaH5), -f 2 HCl = 



C6H2Br(NO,),CH(COOH)2 -f 2 C^H^CI = 

 C,H2Br(N0,),CH,C00H -f CO^-f 2 aH^Cl. 



And there can be no question that a similar reaction takes place when 

 dilute sulphuric acid is substituted for strong hydrochloric acid. In 

 fact, this was so obvious that we have not thought it worth while to 

 try to isolate the sulphovinic acid which must be formed in this case 

 instead of the ethylchloride. 



Properties. — The metabromdinitrophenylacetic acid crystallizes 

 from an aqueous solution containing a little sulphuric acid in yellowish 



* These Proceedings, xxiv. 11. 



