화학공학소재연구정보센터
Industrial & Engineering Chemistry Research, Vol.43, No.26, 8194-8199, 2004
O methylation of phenol in liquid phase over basic zeolites
Liquid-phase 0 methylation of phenol was carried out with dimethyl carbonate (DMC) over as-synthesized KNaX zeolite with impregnated alkaline metal hydroxides. The presence of alkaline hydroxides is associated with hydroxysodalite impurity in the X zeolite. This zeolite exhibited better properties as basic catalyst than those prepared by postsynthesis treatments (ionic exchange). Phenol conversion and selectivity toward anisole were 100% and 85%, respectively, at 438 K with a DMC/phenol molar ratio of 2. The crystallinity and composition of the KNaX zeolite were retained after reaction, making it possible to recover the catalyst without loss of the impregnated alkaline hydroxides during the reaction. The reactivation of the KNaX zeolite was carried out at low temperature (373 K), achieving the same conversion and selectivity to anisole in the phenol methylation as in the first reaction.