Phosphomolybdic Acid Nanoclusters Dispersed in the Micropores of ZrO2-Pillared Clay as an Efficient Catalyst for Synthesis of some Biologically Important Molecules

Abstract

Phosphomolybdic acid dispersed in the micropores of sulphate treated Zr-pillared clay (PMA-SZr-P) was prepared by wet impregnation method. The sulphate treated Zr-pillared clay (SZr-P) was prepared by incorporation of zirconium oxyhydroxy clusters into clay interlayer followed by thermal and sulphate treatments. The resulting materials were characterized by XRD, IR,sorptometric and UV-vis techniques. The formation of thermally stable cross linked Zr-pillared clay was confirmed from the XRD study. The structural integrity of the clay as well as the phosphomolybdic acid in the clay matrix was ascertained from the characteristic IR bands. The UV-vis study indicates good dispersion of PMA interacting in the micropores of Zr-pillared clay. The PMA-SZr-P materials were used as a heterogeneous and recyclable catalyst for the synthesis of some biologically important molecules like coumarins by condensation of phenols with ethylacetoacetate under solvent free condition. The catalyst was found to be highly efficient with good yield and purity of the products.