PREPARATION AND CHARACTERIZATION OF SILICA-SUPPORTED AND MAGNESIA-SUPPORTED POLY(3-AMINOPROPYLSILOXANE)-PLATINUM COMPLEXES AND THEIR CATALYTIC ACTIVITY IN THE OXIDATION OF CYCLOHEXANOL AND CYCLOPENTANOL WITH MOLECULAR-OXYGEN

We have prepared silica- and magnesia-supported poly(3-aminopropylsilo xane)-platinum complexes (abbreviated as Si(O)2-PAPSPt and MgO-PAPSPt, respectively) in which mixed valent platinum is coordinated by amino groups and aggregated to a certain extent. MgO-PAPSPt contains low-val ent, very small and almost homogeneously dispersed platinum aggregates (diameter ca. 20 Angstrom) and is highly active, stable and recyclabl e in the oxidation of cyclohexanol and cyclopentanol under atmospheric pressure of oxygen. In contrast, large platinum aggregates (ca. 30-10 0 Angstrom, 60 Angstrom on an average) are found in SiO2-PAPSPt, and a lmost no zero-valent platinum is present. We assume this is the reason for its very low activity in oxidations under the same conditions.