Immobilization of Polymer-Protected Ultrafine Metal Particles for Catalyst.

Dispersions of ultrafine particle of rhodium were prepared as dark brown homogeneous solutions byrefluxing ethanol-water mixture (1:1 in volume) of rhodium(III) chloride for 1h in the presence ofthe methyl acrylate and N-vinyl-2-pyrrolidone copolymer. Electron microscopy showed that rhodiumparticles having dimateters 20- 80a were highly dispersed without coaggregation and their averagediameter was 50a .The ultrafine particles of rhodium protected by The copolymer are treated withpolyacrylamide gel having amino groupsimmobilization of the particles onto the gel. immobilization was successfullyachieved in the pH region of 4-9. the binding of the particles to the gel was stable，and no release of the particles from the gel was detected when ph of the mixture was changed in awide range (from 2 to 13) after the immobilization. the immobilized catalyst remained also intact当它被重复使用与水。The gel-immobilized rhodium particles exhibited 2-22 foldlarger catalytic activities than a commercial rhodium carbon catalyst for hydrogenation of olefinsat 30c under 1atm。

Dispersions of ultrafine particle of rhodium were prepared as dark brown homogeneous solutions by refluxing ethanol-water mixture (1:1 in volume) of rhodium(III) chloride for 1 h in the presence of the methyl acrylate and N-vinyl-2-pyrrolidone copolymer. Electron microscopy showed that rhodium particles having dimateters 20-80A^^゜ were highly dispersed without coaggregation and their average diameter was 50A^^゜.The ultrafine particles of rhodium protected by the copolymer are treated with polyacrylamide gel having amino groups, resulting in immobilization of the particles onto the gel. The immobilization was successfully achieved in the pH region of 4-9. The binding of the particles to the gel was stable, and no release of the particles from the gel was detected when ph of the mixture was changed in a wide range (from 2 to 13) after the immobilization. The immobilized catalyst remained also intact when it was repeatedly washed with water. The gel-immobilized rhodium particles exhibited 2-22 fold larger catalytic activities than a commercial rhodium carbon catalyst for hydrogenation of olefins at 30 c under 1 atm.