OP ARTS AND SCIENCES. 373 



no matter how the conditions of the reaction were varied. A number 

 of high boiling neutral solvents gave no better results than those ob- 

 tained by heating the acid by itself. The bromfurfurdibrompropionic 

 acid was therefore carefully heated in shallow crystallizing dishes im- 

 mersed in a sulphuric acid bath. The hydrobroinic acid thus escaped 

 without blackening the product to any great extent. The tempera- 

 ture was slowly raised to 130°, and when at this point the formation 

 of hydrobromic acid was no longer noticeable the residue was boiled 

 with dilute ammonic hydrate filtered, heated with bone-black, and the 

 filtered solution concentrated by evaporation. In this way sparingly 

 soluble finely felted needles of ammonic bromfurfurbromacrylate were 

 obtained, which yielded the acid in a state of purity. 



I. 0.2246 grm. substance gave 0.2328 grm. C0 2 and 0.031 7 grm. H 2 0. 

 II. 0.2290 grm. substance gave 0.2373 grm. C0 2 and 0.03H grm. H 2 0. 



III. 0.2059 grm. substance gave 0.2G15 grm. AgBr. 



IV. 0.2025 grm. substance gave 0.2571 grm. AgBr. 



Calculated for Found. 



C 7 H 4 Br 2 s . I. II. HI. IV. 



C 28.38 28.27 28.26 



H 1.35 1.57 1.53 



Br 54.05 54.04 54.03 



Bromfurfurbromacrylic acid is almost insoluble even in hot water. 

 It dissolves freely in ether or alcohol, and when precipitated by water 

 from a hot alcoholic solution is obtained in fine clustered needles. At 

 ordinary temperatures it is very sparingly soluble in chloroform or 

 carbonic disulphide, but dissolves somewhat more freely on heating. 

 The acid melts at 178-179° and small quantities of it may easily be 

 sublimed without essential decomposition. 



In spite of many attempts, we have been unable to obtain experi- 

 mental evidence as to the position of the bromine atoms. We have 

 also been unable to prepare definite products by the addition of bro- 

 mine to the acid, or to form from it bromfurfurpropiolic by the elimi- 

 nation of hydrobromic acid. The following salts may serve for the 

 better characterization of the acid. 



Baric Bromfurfnrbromacrylate, Ba(C 7 H 3 Br 2 0..) 2 . 2 ILO. — This 

 salt was prepared by adding baric chloride to a solution of the ammo- 

 nium salt. It is very sparingly soluble even in boiling water, and 

 crystallizes in lustrous scales. The air-dried salt contain-, two mole- 

 cules of water, which it does not lose over sulphuric acid. 



I. 1.4911 grm. of the air-dried salt lost at 120° 0.0674 grm. 11,0. 

 II. 0.8824 grm. of the air-dried salt lost at 120° 0.0399 gnu. 11./). 



