44 PROCEEDINGS OF THE AMERICAN ACADEMY 



On standing with an alcoholic solution of potassic hydrate, a molecule 

 of bydi'obromic acid was eliminated from the acid with the formation 

 of tribromacrylic acid, according to the equation : 



CgH^Br.O^ + 2 KOH = KCsBrgO^ + KBr + Hp. 



Tribromacrylic acid was recognized by its melting point, 118°, and 



by its crystalline form. 



If the structure of /3-dibromacrylic acid* is represented by the 



formula, — 



CBr^ 



II 

 CH 



I 

 COOH 



the bromine-addition product would have the form, — 



CBr3 



I 

 CHBr 



I 

 COOH 



The above statement concerning the behavior of /3-dibromacrylic 

 acid towards bromine, holds true with regard to chlorine. Although 

 no action takes place at ordinary temperatures, when chlorine is passed 

 through the melted acid the addition-product is formed without diffi- 

 culty. The resulting dichlordibrompropionic acid will be submitted 

 to further examination. 



We have also tried the action of hydrobromic acid upon y8-dibrom- 

 acrylic acid, but as yet our results are as unsatisfactory as those of 

 Fittig and Petri. f The product melted at about 53° and gave a 

 percentage of bromine which showed that it contained much unaltered 

 dibromacrylic acid. Nevertheless, by prolonged heating, we hope to 

 obtain the tribrompropionic acid in a form sufficiently pure to enable 

 us to study its properties. 



Several attempts were made to obtain an addition-product by the 

 action of bromine monochloride on brompropiolic acid. A substance 

 was formed which melted quite constant at 110°-112° ; but the results 

 of analyses indicated that it was a mixture of the chlorine and bromine 

 addition-products. In one experiment a product was obtained which 

 melted at 102°-105°, and the percentage of bromine was very con- 



* H. B. Hill, these Proceedings, Vol. XVII. p. 153. 

 t Ann. der Chem., cxcv. 73. 



