Evidences of the in situ generation of highly active Lewis acid species on Zr-SBA-15

The dramatic increase in activity of reused/treated Zr-SBA-15 in the alkylation of aromatics with benzyl chloride points to the formation of novel highly acidic Lewis Cl x Zr–O–Si species on the catalyst surface. Such materials provided quantitative conversions of starting material in less than 1 h compared to more than 12 h needed for the parent Zr-SBA-15. Zr-SBA-15 materials were synthesized and the activity of the catalysts was investigated in the alkylation of aromatics with benzyl chloride. While Zr-SBA-15 materials needed more than 12 h of reaction to achieve quantitative conversion, an unusually high catalytic activity was observed for reused materials that provided quantitative conversions of starting material in less than 1 h. This dramatic increase in activity observed for reused and/or treated Zr-SBA-15 in the alkylation of aromatics with benzyl chloride points to the formation of novel highly acidic Lewis Cl x Zr–O–Si species on the catalyst surface.