Synthesis and catalytic application of zirconium-substituted aminoethyl phosphonate

A new type of zirconium-substituted aminoethyl phosphonate material is prepared and characterized by elemental analysis, ICP, FTIR, XRD, 31P-MAS NMR, TG, DTG and DSC. XRD indicates that the material is amorphous. The 31P-MAS NMR of the material exhibits a single resonance, and thermogravimetry shows that the material has three steps mass loss at temperatures of up to 900 °C. The zirconium phosphonate material as a solid catalyst is investigated in the Knoevenagel condensation of aromatic aldehyde or cyclohexanone with active methylene compounds. The solid catalyst is easily recovered and can be recycled three times without significant loss of its activity. The experimental results imply the catalytic activity of the zirconium phosphonate is different from that of the organic–inorganic hybrid zirconium phosphonate-phosphate.