Reaction of Terephthalic Acid with Ethylene Oxide

Abstract

In the reaction of terephthalic acid (TPA) with a large excess of ethylene oxide (E0) in the presence of tetraethylammonium terephthalate (AT) catalyst, the rates of the formation of ethylene glycol ester (A) and diethylene glycol ester (B) are expressed by the equations ( 1 )and ( 2 ), respectively:
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The product ratio B/A increases linearly with the conversion of terephthalic acid and the slope of the straight line decreases as the amount of the catalyst increases. Ester B may be generated by further addition of EO to, A once formed by reaction of terephthalic acid with EO, and terephthalic acid takes part in this reaction as a catalyst. The amount of B form ed in the reaction of terephthalic acid with EO is extremely smaller than that formed in the reaction of EO with substituted benzoic acid which is soluble in EO. This may be due to the fact that terephthalic acid is hardly soluble in EO.