Heterogeneous liquid-phase hydration of isobutene by heteropoly acid-polymer composite film catalyst

H3PMo12O40-polymer composite film catalysts were prepared by blending these two materials using a methanol-chloroform mixture by a membrane preparation technique. Polyphenylene oxide (PPO), polyethersulfone (PES) and polysulfone (PSF) were used as blending polymers. A H3PMo12O40-PPO composite catalyst coated on Al2O3 was also prepared. These catalysts were used as heterogeneous catalysts for the liquid-phase tert-butanol (TBA) synthesis from isobutene and water. It was found that all the composite film catalysts showed higher catalytic activities than homogeneous H3PMo12O40 in the TBA synthesis. Among the composite film catalysts, H3PMo12O40-PPO showed the best catalytic performance. Not only high absorption capability of H3PMo12O40-PPO for isobutene but also stability of H3PMo12O40-PPO in the reaction medium was responsible for such a catalytic performance. The H3PMo12O40-PPO/Al2O3 also showed a higher activity than a homogeneous solution of H3PMo12O40.