Applied Catalysis A: General, Vol.478, 81-90, 2014
Molecular size- and shape-selective Knoevenagel condensation over microporous Cu-3(BTC)(2) immobilized amino-functionalized basic ionic liquid catalyst
A novel molecular size- and shape-selective catalyst, microporous metal-organic framework HKUST-1 immobilized amino-functionalized basic ionic liquid (ABIL-OH), was synthesized by facile impregnation and activation. Characterizations and catalytic results revealed that the catalytically active species ABIL-OH could be confined in well-defined HKUST-1 nanocavities via Cu-NH2 coordination bond. The resulting ABIL-OH/HKUST-1 heterogeneous catalyst showed comparable catalytic activity and enhanced selectivity in liquid phase Knoevenagel condensation, and it could be recovered conveniently and reused at least 5 times without significant loss of its catalytic efficiency. Moreover, ABIL-OH/HKUST-1 catalyst demonstrated distinct size- and shape-selective properties for discrimination of reactants in Knoevenagel condensation. It was supposed that diffusion kinetics of reactants might be controlling step and play a more important role than the nature of the substituents in the confined microenvironment. (C) 2014 Elsevier B.V. All rights reserved,
Keywords:Size and shape-selective catalysis;Metal-organic framework;Cu-3(BTC)(2) nanocavities;Amino-functionalized basic ionic liquid;Immobilization