214 PROCEEDINGS OF THE AMERICAN ACADEMY 



lodhromacrylic Acid. 



Brompropiolic acid dissolves readily in concentrated hydriodic acid, 

 (b. pt. 127°) and so rapid is the action that in a few moments the solu- 

 tion is filled with crystals of the addition-product. The crude acid 

 is pressed between folds of filter paper, and recrystallized from hot 

 water. 



The acid separates from a hot concentrated solution as an oil, but 

 at a lower temperature it crystallizes in pearly scales, which melt at 

 1 10°. The acid is readily soluble in alcohol, ether, or chloroform, but 

 sparingly in benzol, carbonic disulphide, or ligroiu. 



I. 0.3800 grm. substance gave 0.1828 grm. Cog and 0.0307 grm. 

 H,0. 

 II. 0.2945 grm. substance gave 0.4480 grm. AgBr -\- Agl. 



Calculated for C3HjBrI02. Found. 



I. n. 



C 12.99 13.12 



H 0.70 0.90 



f1 



74.73 74.47 



The solubility of the acid in cold water we determined by neutral- 

 izing the saturated aqueous solution, made according to the method of 

 V. Meyer with baric carbonate, and evaporating with sulphuric acid. 



I. 11.1382 grm. of a solution, saturated at 20°, gave 0.0785 grm. 

 BaSO,. 

 11. 10.8923 grm. of a solution, saturated at 20°, gave 0.0783 grm. 

 BaSO^. 



According to these determinations, the aqueous solution of the acid 

 saturated at 20° contained the following percentages : — 



I. 11. 



1.68 1.71 



For the further characterization of the acid, we prepared the 

 barium, calcium, and silver salts. 



Baric lodbromacrylate, Ba(CgHBrI02)2-3H2C)- The barium salt 

 we made by saturating the aqueous solution of the acid with baric 

 carbonate and concentrating on the water bath. From concentrated 

 solutions it crystallizes in fine needles ; from more dilute, in rectangu- 

 lar plates. The air-dried salt contains three molecules of water, 

 which it loses in vacuo over sulphuric acid. 



