60 The Philippine Journal of Science i9i6 



to the method of Herrman.' The compound melted at 133°, the 

 melting point given by the latter. It was titrated with alcoholic 

 bromine solution ® to determine the percentage content of enol 

 and keto modifications. This titration showed that 90 per cent 

 of p-dioxyterephthalic ester exists in alcoholic solution in the keto 

 form and only 10 per cent in the enol form. The alcoholic 

 solution was greenish yellow with a deep blue fluorescence under 

 the arc. It showed two bands, one heading near the visible 

 region at 1/A=2,660 and a much more refrangible one in the 

 ultra-violet region at 1/A=4,010. This compound was also pho- 

 tographed in the presence of two equivalents of sodium ethylate. 

 The same bands appear, and the position of the first lay largely 

 in the visible region, heading at 1/A.=2,375, while the second had 

 not shifted. 



p-DIACETATE OP TEREPHTHALIC ESTER 



COOC2HB 



I 



H-/^|-00CCH3 



HsCCOO-l^^'-H 



I 

 COOC2H5 



The acetate was prepared in the manner described by Nef ^ 

 for the preparation of the diacetyl derivative of succinosuccinate 

 by treating the sodium salt of dioxyterephthalate with acetyl- 

 chloride. After crystallizing from glacial acetic acid and later 

 from alcohol, it was obtained in colorless white plates melting at 

 154°. The alcoholic solution gave only a very faint blue 

 fluorescence in the light of the arc. An incipient band appears 

 at 1/A=2,900, while a more decided band appears at 1/A=3,390. 



2)-DIAMn)0TEREPHTHALIC ESTER 



COOC2H5 



-^ .. _ - I 



!" ■ ■■■'■ ■ H— ^-NHa - 



I 



, COOC2H5 



•Ibid. (1882), 211, 327: 



•Ibid. (1911), 380, 212. 



'Am. Chem. Journ. (18&0), 12, '416. 



