摘要:
Composite zirconium phosphonates in single crystal phase have been investigated and characterized by XRD, C-13-, and P-31-MASNMR. These compounds are lamellar structures comprising zirconium organophosphonates. Each layer consists of planes of zirconium bridged through phosphonate groups that 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 esterification of acetic acid. When the composite zirconium phosphonate includes an acidic function and with a hydrophobic function in single crystal phase, the catalytic activity showed a higher activity than that of sulfonic acid catalyst. The composite zirconium phosphonates become accessible to any reactant molecule and improve hydrophobicity around acidic sites. (C) 1999 Elsevier Science B.V. All rights reserved.