Investigation on the catalysis performance of metal-doped zeolites on ring-opening acidolysis reaction

Metal-incorporated zeolites as heterogeneous Lewis acid were applied in the ring-opening acidolysis of ethylene oxide with acrylic acid to prepare 2-hydroxyethyl acrylate (HEA). The catalysis characteristics, including Lewis acid strength and internal mass transfer resistance, were systematically investigated to facilitate the rational design of zeolite catalysts. Through modifying the Lewis acid strength of zeolites via different metals (Sn, Zr and Ti) incorporation and the internal mass transfer resistance of zeolites from the particle size, pore diameter or pore structure, it was found that the increased Lewis acidity can accelerate both the main and side reactions, resulting in the high activity but low selectivity of zeolite catalysts; the enhanced internal diffusion was the key to limiting subsequent cascade alcoholysis side reactions as well as the decline of catalytic performance. Based on these findings, Zr-containing zeolites featured with moderate Lewis acidity and uniform intracrystalline mesoporosity were designed and prepared, presenting excellent catalysis and recycling performance. These results demonstrated the great potential of the developed zeolite catalysts for the green synthesis of HEA as well as the similar ring-opening acidolysis of epoxides.