Direct synthesis of mesoporous zeolite ETS-10 and Ni-ETS-10 with good catalytic performance in the Knoevenagel reaction

Abstract

Developing highly active heterogeneous catalyst with strong basicity and porous structure is a highly attractive strategy for the base-catalyzed organic chemistry. Herein, we directly synthesized the mesoporous zeolite ETS-10 (METS-10) from using a water glass contained cationic copolymer with quaternary ammonium groups as a template. Furthermore, when the nickel nitrate solution was added into the starting synthesis gel, the nickel species facilitated the mesopore formation, and the Ni-containing mesoporous zeolite ETS-10 (Ni-METS-10) was obtained. Catalytic test results showed that the conversions of the benzaldehyde and citral over Ni-METS-10 (88.8 and 63.2 %) and METS-10 (85.5 and 60.1 %) catalysts are higher than those over both mesopore-free ETS-10 (77.3 and 47.7 %) and mesoporous NaX (MNaX, 55.0 and 35.2 %) catalysts in the condensation reactions with ethyl cyanoacetate. The higher activity of METS-10 and Ni-METS-10 than ETS-10 and MNaX is assigned to the fact that the strong basic sites on the catalysts can activate the reaction substrate and the mesoporous in the catalyst benefit the mass transfer and enhance the catalytic activity.