Influence of Reaction Conditions on Main and Side Reactions During the Transesterification of Dimethyl Terephthalate with 1, 4-Butanediol

The transesterification of dimethyl terephthalate (DMT) with 1, 4-butane-diol (BD) has been studied by measuring the amount of methanol and tetrahydrofuran formed during the reaction. Investigation of various catalyst systems revealed that titanium isopropoxide was a better catalyst than conventional transesterification catalysts such as manganese and cobalt acetates. Increases in the temperature, BD/DMT ratio, and catalyst concentration led to higher production of methanol. Increases in temperature and BD/DMT ratio raised THF production, but increased catalyst concentration decreased the amount of THF produced. The relative importance of BD dehydration and cyclization of 4-hydroxy-butyl ester end groups in the formation of THF was also studied.