OF ARTS AND SCIENCES, 291 



/3-Bromdichloracrtlic Acid. 



/3-clibromdichlorpropionic acid is readily decomposed by alkaline hy- 

 drates, and when the reaction is allowed to progress in the cold, the 

 elements of hydrobromic acid are eliminated with the formation of the 

 corresponding substituted acrylic acid. The best results were obtained 

 by treating the acid with an aqueous solution of baric hydi'ate in slight 

 excess over the calculated amount, and keeping the solution slightly 

 alkaline for twenty-four hours. Upon acidifying this solution with 

 hydrochloric acid, dichlorbromacrylic acid was partially precipitated 

 as an oil, which solidified when cooled to 0°. Since the acid is quite 

 soluble in water, the solution was extracted with ether, and the total 

 product was purified by several crystallizations from hot water. 



This acid is very soluble in hot, rather sparingly soluble in cold 

 water, and very soluble in carbonic disulphide, chloroform, ether, and 

 alcohol. It crystallizes from water in lai'ge pearly scales, whicn melt 

 at 75°- 78°. Its composition was determined by analysis. 



I. 0.2374 grm. of the substance gave 0.5059 grm. AgCl + AgBr. 

 II. 0.2034 grm. of the substance gave 0.4377 grm. AgCl + AgBr. 

 III. 0.7255 grm. of the substance gave 0.4433 grm. CO, and 0.0337 

 grm. H^O. 



In determining the solubility of this acid in cold water, a solution 

 saturated at 20° was neutralized with baric carbonate, and the barium 

 was determined in the filtered solution. 



I. 6.0061 grm. of a solution saturated at 20° gave 0.1523 grm. BaSO^. 

 11. 7.4519 grm. of a solution saturated at 20° gave 0.1872 grm. BaSO^. 



From these results the following percentages were calculated: — 



I. II. 



4.79 4.74 



This acid is characterized by a series of well-defined salts, several of 

 which were prepared for analysis. 



Baric ^-Bromdichloracrylate, Ba(C3Cl2Br02)2 . 3 H,0. — The ba- 

 rium salt was made by neutralizing the acid in aqueous solution with 



