Preparation, characterization and catalyst application of ternary interpenetrating networks of poly 4-methyl vinyl pyridinium hydroxide–SiO2–Al2O3

In this work, Al2O3 was mixed with SiO2 and poly 4-vinylpyridine by the sol–gel method in order to make a composite which is used as a heterogeneous basic catalyst for Knoevenagel condensation reaction. The physical and chemical properties of the composite catalyst were investigated by XRD, FT-IR, TG, BET and SEM techniques. The catalytic performance of each material was determined for the Knoevenagel condensation reaction between carbonyl compound and malononitrile. The reactions were performed in solvent-free conditions and the product was obtained in high yield and purity after a simple work-up. The effects of the amount of catalyst, amount of monomer for the synthesis of composite and recyclability of the heterogeneous composite were investigated. The composite catalyst used for this synthetically useful transformation showed considerable level of reusability besides very good activity.

Graphical abstractIn this paper, we report the synthesis of poly 4-methyl vinyl pyridinium hydroxide–SiO2–Al2O3. The novelty of this procedure is at easy preparation together with using inexpensive materials.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► P4MVPH–SiO2–Al2O3 composite was prepared as a novel polymer-inorganic hybrid. ► The composite was prepared without using any bridged organosilanes compound. ► SEM photograph showed that the composite is completely uniform. ► P4MVPH–SiO2–Al2O3 could behave as a recyclable catalyst for Knoevenagel reaction.