Liquid Metal-Assisted Acylation of Phenols over Zeolite Catalysts
Résumé
The selection of a solvent for the reaction is highly important in catalysis since it profoundly affects the catalytic activity, selectivity, and stability. However, the costly separation of solvent from the products hinders the application of solvents in industry. In this study, we propose liquid metals to regulate the catalytic performance of nonmetallic zeolite catalysts. The catalytic reactions of phenol acylation over a heterogeneous acidic BEA zeolite were conducted in the presence of liquid metal alloys above their melting points. The presence of liquid metals in the reaction medium leads to a dramatic change of the selectivity toward ester formation in the phenol acylation reactions at high stability of the catalyst. The observed phenomena were attributed to a strong interaction of the liquid metal with the catalysts, resulting in the modification of the strength of the zeolite acid sites and a decrease in the residence time of the products on the surface of the catalyst.