Silica Supported Ammonium Acetate: An Efficient and Recyclable Heterogeneous Catalyst for Knoevenagel Condensation between Aldehydes or Ketones and Active Methylene Group in Liquid Phase

A simple and efficient method has been developed for Knoevenagel condensation between aldehydes or ketones and active methylene group by stirring in methylene chloride at 60 oC under heterogeneous conditions using silica supported ammonium acetate. The products are obtained in excellent yields and are in a state of high purity. The structures of the products were confirmed by IR, 1H NMR and mass spectral data and comparison with authentic samples available commercially