The effect of acid sites in zeolite Beta for activity and selectivity in acylation of toluene

Zeolite Beta of various concentrations and types of acid sites was investigated in toluene acylation with isobutyric acid derivates. Catalytic activities of zeolites Beta having Si/Al molar ratios between 11.2–110 were compared using conversions of isobutyryl chloride and selectivities to sum of isopropyltolylketone achieved. Commercial and synthesized samples of Beta zeolites, were characterized by X-ray powder diffraction (XRD), chemical analysis (CA), scanning electron microscopy (SEM), infrared spectroscopy (FT-IR), nuclear magnetic resonance (27Al MAS NMR, 29Si MAS NMR) and sorption measurements for maximum description of these zeolites and for better explanation of resulting activities of these catalysts in acylation reactions. The highest activities were obtained over zeolites Beta possessing the lowest Si/Al ratio and one of the highest concentrations of Lewis and Brønsted acid sites.