OF ARTS AND SCIENCES. 175 



Tribrompyromucic Acid. 



Tribrompyromucic acid can readily be made from S-monobrompyro- 

 mucic tetrabromide by the action of an alcoholic solution of sodic 

 hydrate. Although, as has already been remarked, this acid is formed 

 through secondary reactions in the preparation of the dibrompyromucic 

 acids from pyi-omucic tetrabromide, we have obtained in this way but 

 a small quantity of the acid, and have prepared most of the material 

 we have needed for the investigation from monobrompyromucic acid. 

 The formation of the tribrompyromucic acid by the action of bromine 

 upon the ySy-dibrompyromucic acid has already been noticed. Since 

 the hydrogen of the isomeric dibrompyromucic acid cannot be directly 

 replaced by bromine, tribrompyromucic acid cannot be made by the 

 direct action of bromine upon pyromucic acid. 



In the decomposition of the monobrompyromucic tetrabromide we 

 have found a low temperature and a concentrated solution of sodic 

 hydrate advantageous. The sodium salt of the tribrompyromucic acid 

 is but sparingly soluble in alcohol, and may be separated by filtration. 

 The alcoholic mother-liquors proved to contain a substance insoluble 

 in water and readily volatile with the vapor of alcohol. For its iso- 

 lation we precipitated the excess of sodic hydrate with carbonic dioxide, 

 distilled the filtered solution, and precipitated the distillate by the ad- 

 dition of water. The heavy oil which was thus thrown down we dried 

 with calcic chloride, and submitted it to fractional distillation in an 

 atmosphere of carbonic dioxide under diminished pressure. After 

 several distillations, by far the greater portion of the oil showed the 

 constant boiling-point 96-98° under a pressure of 20 mm., and we 

 were unable to isolate other definite products. An analysis showed 

 the main product to be a tribromfurfuran. 



0.3-il7 grm. substance gave 0.6299 AgBr. 



Calculated for CiHBrgO. Found. 



Br 78. G8 78.39 



Tribromfurfuran had, therefore, been formed from the monobrom- 

 pyromucic tetrabromide according to the equation, 



C.H^Br.O, ^ C,HBr30 +00,-1-2 IIBr. 



The sodium salt which had separated from the alcoholic solution we 

 acidified with hydrochloric acid, and recrystallized the acid thus ob- 

 tained from dilute alcohol, and finally from water. 



