Effect of solvents and polymer supports on catalytic activity of polymer - supported catalyst

Abstract

In order to design polymer-supported catalyst for a given reaction, the effect of interaction among solvent, polymer, and reactant on catalytic activity was systematically studied. As an example for designing polymer-supported catalyst, a catalyst which was highly active or selective was proposed for olefin hydrogenation in this thesis. The formation mechanism of hollow bead was discussed in chapter 2. For preparation of styrene-divinybenzene copolymer bead by suspension polymerization, the domain of hollow bead was roughly defined in a map where abscissa is reaction temperature and ordinate is initiator amount by a curve. The outer and the inner surfaces of hollow polymer bead consisted of many nodules of which size was affected by reaction conditions. The wall thickness of hollow bead depends on the polymerization temperature, the amount of initiator, and it seems to be more dependent on the rate of increasing temperature from initial temperature to polymerization temperature. The wall thickness of hollow bead was thinner than expected by volume change as polymerization proceeded due to The tangential stress at the surface of organic droplet by the suspending fluid and the generation of nitrogen by decomposition of initiator during suspension polymerization. To obtain gelular polymer bead, the polymerization should be carried out in gelular domain. To study the effect of the interaction among solvent, reactant, and polymer on the catalytic activity, the hydrogenation of cyclohexene was carried out over unsupported and polymer-supported catalyst under various solvents. Palladium dichloride was supported onto a vinylpyridine-divinybenzene copolymer bead to prepare the polymer-supported catalyst with N:Pd molar ratio from 2.17 to 3.93 and reacted with ethylpyridine to prepare non-supported catalyst. The supported catalyst was crushed to powder to remove diffusional effects in heterogeneous catalytic reaction. Those catalysts were used for the hydrogenation of c...