Effect of the Method of Modification of Zeolite X on Selectivity of Catalytic Methylation of Toluene

Abstract

The effect of the method of modification of catalysts based on zeolite X by cesium and magnesium cations (ion exchange and impregnation) on the selectivity of the alkylation of toluene with methanol was determined. It was shown by IR spectroscopy that the presence of strong Lewis acid sites (LAS) in the zeolites levels out the positive effect of the increased basicity of the framework oxygen atoms achieved by impregnation of (Mg-, Cs-)X samples with cesium nitrate. Ion-exchange modification of the catalysts, which eliminates the strong LAS, is an essential condition for increasing their selectivity for styrene and ethylbenzene.