XI. A, 2 Brill: Diethylsuccinosuccinate, II 63 



' Ai,4-DIHYDR0TEREPHTHALIC ESTER 



COOCH3 



H/1 r^ 



COOCH3 



The Ai4-dihydroterephthalic methyl ester was prepared by 

 treating a solution of the sodium salt of terephthalic acid with 

 sodium amalgam" for some time, warming at intervals, and 

 afterward forming the methyl ester by adding methyl alcohol to 

 the intimate mixture of phosphorus pentachloride " and Ai,4 

 dihydroterephthalic acid. This ester melts at 133° when purified 

 by repeated crystallization from methyl alcohol, in which it is 

 readily soluble. When photographed, a very shallow band is 

 seen at 1/a=3,480 with a decidedly refrangible band at 1/A= 

 4,140. The alcoholic solution shows slight blue fluorescence in 

 the light of the arc. 



TEREPHTHALIC ESTER 

 COOC2H5 



H-l J-H 



COOC2H5 



The ethyl ester of terephthalic acid prepared from terephthalic 

 acid by the method used for the preparation of the methyl ester 

 of dihydroterephthalic acid is a colorless crystalline body, melt- 

 ing at 43° C. when purified by crystallization from alcohol. It 

 gives two rather well-defined bands in the ultra-violet region, 

 one at 1/A=3,480 and the other at 1/A=4,175, at lower con- 

 centration than the bands for the dihydroterephthalate. 



"Baeyer, Ann. d. Chem. (1889), 251, 290. 

 "Baeyer, ibid. (1888), 245, 140. 



