OF ARTS AND SCIENCES. 99 



It also gave the percentage of bromine required for tribromacrylic 

 acid. 



0.1553 grra. substance gave 0.2819 grm. AgBr. 



Calculated for CgHBrgOa. Found. 



Br 77.66 77.25 



Chlorbromiodacrtlic Acid. 



Chlorbromiodacrylic acid may be prepared most conveniently by 

 heating brompropiolic acid with an ethereal solution of iodine mono- 

 chloride, although without the application of heat the reaction takes 

 place slowly. Iodine monochloride was made according to the method 

 proposed by Bunsen.* Tlie calculated weight of iodine was dissolved 

 in aqua regia with the aid of heat, and after cooling the solution was 

 extracted with ether and washed thoroughly with water. When brom- 

 propiolic acid is heated for an hour with this solution, the oily liquid 

 left on evaporation of the ether soon deposits large prismatic crystals 

 of the addition-product. For purification the crude product was 

 pressed in filter paper and recrystallized from hot water. 



This substance is readily soluble in ether and alcohol, somewhat less 

 so in carbonic disul^ohide and chloroform. From a hot aqueous solu- 

 tion it separates as an oil which crystallizes on cooling in rhombic 

 prisms of the monoclinic system. By crystallization from water we 

 did not succeed in raising the melting point above 110° ; but the crys- 

 tals formed by slow evaporation of a solution in carbonic disulj^hide 

 melted at 115-116°. It sublimes freely at somewhat higher tempera- 

 tures. 



This acid was identified by the following analyses : — 



I. 0.G743 grm. substance gave 0.2843 grm. COj.f 

 II. 0.1505 grm. substance gave 0.2721 grm. AgCl -f AgBr -j- 

 Agl. 



Calculated for CaHClBrlOi. Found. 



I. II. 



C 11.55 11.50 



• H .32 



CI + Br -f- I 77.84 77.41 



* Ann. Chem. u. Pharm. LXXIV. 8. 



t By an accident the water in this combustion was lost. 



