An Amphiphilic Resin-dispersion of Nanoparticles of Platinum (ARP-Pt): A Highly Active and Recyclable Catalyst for the Aerobic Oxidation of a Variety of Alcohols in Water

An amphiphilic polystyrene-poly(ethylene glycol) (PS-PEG) resin-dispersion of nanoparticles of platinum (ARP-Pt, 4) was developed with a view towards use in catalysis in an aqueous environment under heterogeneous conditions. ARP-Pt 4 was prepared by the reduction of PS-PEG-NH2-PtCl2(C2H4) 3, which was generated by mixing PS-PEG-NH2 1 and Zeise's salt 2 (K[PtCl3(CH2CH2)]), with benzyl alcohol in water (80 degrees C, 12 h). Benzyl alcohol was an essential reducing agent for the preparation of Pt nanoparticles with a narrow size distribution (phi = 5.9 +/- 0.75 nm) throughout the PS-PEG resin, whereas the reduction of 3 with NaBH4 gave Pt nanoparticles with broad size distribution (phi = 2-150 nm). ARP-Pt 4 was found to catalyze the aerobic oxidation of a wide variety of alcohols, including non-activated aliphatic and alicyclic alcohols, in water with atmospheric oxygen or air under heterogeneous conditions, and was reused without loss of its catalytic activity, to achieve a highly environmentally-friendly reaction.