238 PROCEEDINGS OP THE AMERICAN ACADEMY 



Calculated for AgCgljBrOj. Found. 



Ag 21.17 21.02 



Poiassic Diiodbromacrylate, KC3l2Br02.2H20. A solution of tde 

 acid was neutralized with potassic carbonate, and evaporated on the 

 water bath. On cooling, the salt separated in the form of oblique 

 prisms, which are quite soluble in water. 



1.8818 grm. of the air-dried salt gave 0.1381 grm. HjO at 80°. 



1.7460 grm. anhydrous salt gave 0.3347 grm. KgSO^. 



Calculated for KC3l2BrOs.2HjO. Found. 



HgO 7.55 7.33 



Calculated for KCsIjBrO,. Found. 



K 8.87 8.50 



Chlorbromacrtlic Acid, CgClBrCgHg. 



Chlorbromacrylic acid may be made by the action of ordinary fuiu 

 ing hydrochloric acid on brompropiolic acid. This reaction, however, 

 takes place slowly in the cold ; and, although the application of heat 

 causes a more rapid formation of the chlorbromacrylic acid, it pro- 

 duces a secondary decomposition which renders the purification of the 

 product somewhat difficult. We therefore tried the action of hydro- 

 chloric acid saturated at 0°. The acid solution soon became filled 

 with crystals of the addition product ; and after standing twenty-four 

 hours the reaction was complete. The excess of hydrochloric acid 

 was removed by decantation, and by pressure between folds of filter 

 paper, and the chlorbromacrylic acid was purified by crystallization 

 from hot water. It separates as an oily liquid from a hot aqueous 

 solution ; but when nearly cold it crystallizes, forming elongated, 

 flat prisms or needles. 



This acid melts at 70°, and sublimes quite freely at a somewhat 

 higher temperature. It is much more soluble in hot than in cold 

 water, and readily soluble in ether, alcohol, benzol, and carbonic disul- 

 phide. Its composition was determined by the following analyses : — 

 0.4462 grm. substance gave 0.3126 grm. COj and 0.0337 grm. HoO. 

 0.1792 grm. substance gave, by the method of Carius, 0.3186 grm. 



AgCl -f- AgBr. 



Calculated for CsClBrOjHj. Found. 



C 19.40 19.11 



H 1.08 .84 



Cl-fBr 62.26 61.94 



