Catalytic oxidation by polymer-supported copper(II)-L-valine complexes

Anchoring of an amino acid L-valine on cross-linked styrene-divinyl benzene was carried out in presence of a base. Reaction of cupric acetate with the polymeric ligand resulted in chelate formation with Cu(II) ion. The immobilized Cu(II) catalysts were characterized by elemental analyses, IR, UV-Vis, SEM, ESR and thermal analysis. Physico-chemical properties like surface area, apparent bulk density, pore volume, etc. have been determined. The supported Cu(II) complexes behave as versatile catalysts in the oxidation of various substrates such as benzyl alcohol, cyclohexanol and styrene in presence of t-butyl hydroperoxide as oxidant. The effect of reaction conditions on conversion and selectivity to products has been studied in detail. Preliminary kinetic experiments reveal that the Cu(II) complexes attached to polymer matrix can be recycled about four times with no major loss in activity. (C) 2003 Elsevier B.V. All rights reserved.