Mesopolymer solid base catalysts with variable basicity: preparation and catalytic properties

Abstract

A series of amine- or diamine-functionalized mesopolymers with cubic or hexagonal mesostructures have been prepared by two-step chemical modification procedures involving chloromethylation of the FDU-type mesoporous resol materials first with chloromethyl methyl ether, and a subsequent amination reaction with methylamine, dimethylamine or ethylenediamine. Various techniques such as XRD, SEM, TEM, N₂ adsorption, FTIR, ¹³C NMR and elemental analysis have been adopted to track the functionalization processes, and to characterize the structures, porosity, chemical compositions and basicity of the materials. The amino group-containing mesopolymer materials prove to be efficient heterogeneous base catalysts in Knoevenagel condensation of benzaldehyde with ethyl cyanoacetate. The possible mechanisms of Knoevenagel reaction on different mesopolymer base catalysts have also been discussed.