Design of novel catalyst imbedding heteropoly acids in polymer films: Catalytic activity for ethanol conversion

Membrane-like H₃PMo₁₂O₄₀ or H₅PMo₁₀V₂O₄₀-imbedded polymer films were prepared by blending these materials using a chloroform-methanol mixture as solvent, and they were tested as catalysts for the ethanol conversion reaction in a continuous flow fixed-bed reactor. It was found that the chloroform-methanol mixture itself gave no influence on the catalytic activity of bulk H₃PMo₁₂O₄₀ and H₅PMo₁₀V₂O₄₀. Polysulfone, polyethersulfone and polyphenylene oxide were used as blending polymers in this study. H₃PMo₁₂O₄₀-imbedded polymer films showed a higher catalytic activity than H₃PMo₁₂O₄₀ itself due to uniform and fine dispersion of H₃PMo₁₂O₄₀ through polymer films, but the extent of activity and selectivity was varied according to a kind of polymer materials. It was revealed that H₃PMo₁₂O₄₀ or H₅PMo₁₀V₂O₄₀-imbedded polyphenylene oxide film showed much higher oxidation catalytic activity than the corresponding bulk heteropoly acids. This may be due to the interaction (or bonding) of proton of heteropoly acid with polyphenylene oxide, judging from the fact that glass transition temperature of polyphenylene oxide was increased after blending with heteropoly acid. The catalytic activity of the heteropoly acid imbedded in the same polymer was greatly affected by the composite of heteropoly acid. The permeabilities of reactants through polymer films also affected the product selectivity.