OF ARTS AND SCIENCES. 167 



We have obtaiiieil usually about seventy per cent of the theoretical 

 yield of mouobrommaleyl bromide, and have been able to isolate no 

 other products of the reaction except such as would naturally result 

 from its decomposition with water. 



Action of Nitric Acid. 



The /88-dibrompyromucic acid is readily oxidized, with evolution of 

 carbonic dioxide, by boiling even with dilute nitric acid. We have 

 found two parts of strong nitric acid (sp. gr. 1.42), diluted with ten 

 parts of water, sufficient for the complete oxidation of one part of 

 the acid. After the reaction was ended, we extracted the solution 

 with ether and crystallized from water the product obtained by the 

 evaporation of the ether. This product appeared to contain nothing 

 but an acid melting at 174—175°, which on analysis gave the percentage 

 of bromine required by monobromfumaric acid. 



0.2254 grm. substance gave 0.2186 grm. AgBr. 



Calculated for O^IIaBrO^. Found. 



Br 41.03 41.28 



Since we have already shown that the product formed by the action 

 of aqueous bromine is a derivative of monobrommaleic acid, we have 

 not hesitated to assume that the first product of the oxidation with 

 nitric acid also is monobrommaleic acid, and that this is converted into 

 monobromfumaric acid by the continued boihng with nitric acid. The 

 reaction may be written, 



CgHgBrA + + H^O = C.HaBrO, + CO^ + HBr. 



ySy-DlBROMPYROMUCIC AciD. 



The formation of /3y-dibrompyromucic acid from the pyromucic 

 tetrabromide has already been described, and we have not been able 

 to find any other method for its preparation. For ana1y.sis, the acid 

 was recrystallized several times from water, and finally from benzol. 



I. 0.6274 grm. substance gave 0.5065 grm. COj and 0.0445 grm. 



H,0. 

 II. 0.2165 grm. substance gave 0.3019 grm. AgBr. 

 III. 0.2225 grm. substance (rave 0.3106 grm. AgBr. 



