OF ARTS AND SCIENCES. 289 



Chlortribrompropionic Acid. P-Chlordibromacrylic Acid. 



CBr.Cl CBrCl 



I II 



CUBr CBr 



I I 



coon COOH 



Since the formula of /3-clilorcIibromacrylic acid is identical with (1), 

 the structure of the a-acid is probably represented by (2) ; or during 

 the addition of chlorine monobromide to bromprojoiolic acid, the weaker 

 halogen unites with the terminal carbon atom. 



No. III. — ON /3-DIBROMDICriLORPROPIONIC AND 

 ^-BROMDICHLORACRYLIC ACIDS. 



By Charles F. Mabery and II. H. Nicholson. 



)3-DlBROMDICHLORPROPtONIC AciD. 



In a brief examination of the action of chlorine on /3-d ibrom acrylic 

 acid, it was found by F. C. Robinson and one of us,* that, although 

 the acid was not affected at ordinary temperatures, an addition-product 

 could readily be obtained by raising the temperature. Further study 

 of this reaction shows that the most desirable results are obtained as 

 regards time, as well as the quality and quantity of the product, if the 

 temperature is kept near 100°. In one experiment after continuing 

 the action for eight hours 5.9 grm. /3-dibromacrylic acid gave 7.9 grm. 

 of the crude /3-dibromdichlorpro2iionic acid, which melted without pu- 

 rification above 90°, or ninety-six per cent of the amount of pure acid 

 theoretically required. 



The crude acid was easily purified by two or three crystallizations 

 from a hot solution in carbonic disulphide, which deposited the greater 

 part of the acid when cooled to 0°. It is but sparingly soluble in 

 water, more soluble in hot than in cold chloroform, and very soluble 

 in ether and alcohol. It crystallizes in oblique prisms, which melt at 

 100° and sublime slowly at higher temperatures. The composition 

 of this acid was determined by the following analyses : — 



I. 0.2142 grm. of the substance gave 0.4712 grm. AgCl -f AgBr. 

 II. 0.8223 grm. of the substance gave 0.3485 grm. CO., and 0.0510 

 grm. HgO. 



* These Proceedings, Vol. XVIII. p. 44. 



VOL. XIX. (n. S. XI.) 19 



