172 PROCEEDINGS OP THE AMERICAN ACADEMY 



The )8y-dibrompvromucic acid appears to be incapable of forming 

 an addition product with bromine. AVhen the acid is exposed to an 

 atmosphere of bromine at ordinary temperatures, hydrobromic acid 

 is evolved, and tribrompyromucic acid is formed. This we identified 

 by its melting-point, 218-219°, and by its other physical properties. 



Action of Bromine and Water. 



Toennies obtained, by the action of bi'cmine water upon the dibrom- 

 pyromucic acid melting at 186°, a substance to which he assigned the 

 formula C^HoBr.^O.,, and which he named dibromfumaric aldehyde. 

 He published, however, in the preliminary paper to which we have 

 already alluded,* no analycis of the substance. We have found that 

 the action of aqueous bromine varies greatly, according to the condi- 

 tions of the reaction ; and although we have been able to prepare a 

 substance whose properties nearly correspond to Toennies's descrip- 

 tion of the dibromfumaric aldehyde, we have not succeeded in making 

 the yield satisfiictory. If one molecule of bromine is slowly added by 

 means of a current of air to the acid suspended in water, the color 

 of the bromine gradually disappears, a part of the acid remains unal- 

 tered, while a part of it is converted into tetrabromfurfuian. After 

 the solution had become colorless, we collected upon a filter the in- 

 soluble product, and washed it with a dilute solution of sodic carbonate. 

 On acidifying the alkaline solution, the unaltered acid melting at 191° 

 wa3 precipitated. The solid insoluble in the solution of sodic car- 

 bonate dissolved readily in alcohol, and on cooling crystallized in long 

 needles which melted at 64-65°, and gave on analysis the percentage 

 of bromine required by tetrabromfurfuran. 



0.2201 grm. substance gave 0.4319 grm. AgBr. 



Calculated for CjBr^O. Found. 



Br 83.33 83.52 



A portion of the acid had therefore been decomposed according to 

 the equation, 



CgHoBrA + 2 Br, = C,Br,0 + CO, + 2 HBr. 



From the aqueous solution which had been filtered from the tetra- 

 bromfurfuran and the unaltered acid we obtained by extraction with 

 ether a small quantity of a substance which, when recrystallized from 



* Berichte d. deutsch. cliem. Gesellscli., xii. 1203. 



