New route to glucose-derived terephthalic acid using zeolite catalysts

A new series of zeolite-catalyzed Diels-Alder cycloaddn. and dehydrative aromatization reactions between oxygenated furan dienes and ethylene are reported. It is found that pure Lewis-acid zeolites (Sn-BEA) are catalysts for the conversion of 5-substituted furoic acid derivs. and ethylene to 4-substituted benzoic acid derivs. For example, the diene, Me 5-(methoxymethyl)-furan-2-carboxylate, is converted to the dehydrated Diels-Alder product upon reaction with high-pressure (1000 psig) ethylene at 190°C (selectivity can be over 50%). The arom. product of this reaction, Me 4-(methoxymethyl)benzoate, can be used to produce terephthalic acid or its diester via oxidn. This new reaction pathway opens a completely new route for the prodn. of terephthalic acid starting from glucose-derived HMF (5-hydroxymethyl-2-furfural) and ethylene, and avoids any costly redn. steps