MOLECULAR DESIGN OF LAYERED ZIRCONIUM PHOSPHONATE CATALYSTS

Abstract

Preparation and characterization of two-dimensional zirconium phosphonate derivatives have been investigated. Two composite zirconium phosphonates in single crystal phase have also been investigated and characterized by XRD, 13C-, and 31P-MASNMR. These compounds are lamellar structures comprising zirconium phosphates or organophosphonates. Each layer consists of planes of zirconium bridged through phosphonate groups which alternate above and below the Zr atom planes, oriented away from the basal surfaces in a bilayered fashion in the interlayer region. The catalytic performance over zirconium phosphonates is evaluated by hydrolysis of ethyl acetate or by esterification of acetic acid. When the composite zirconium phosphonate is composed with an acidic function and with a hydrophobic function in single crystal phase, the catalytic activity showed a higher activity without swelling of the catalyst in the reaction media. The composite materials become accessible to any reactant molecule and improve hydrophobicity.