Heterogenizing homogeneous hydrogenation catalysts

Catalysts frequently used in the fine chemical industries are qften homogeneous, therefore requiring expensive and time consuming methods of catalyst regeneration. The loss of expensive transition metals used in most homogeneous catalysts is significant, and further tests must be conducted to measure levels of contamination of the final product, a critical consideration in the phannaceutical and foodstuffs industries. This thesis reports the synthesis, material preparation and testing of three methods of entrapping active catalysts. The methods described have been developed to fulfill the conditions suitable for the individual catalyst. Acidic, basic and fast gelling sol-gel techniques are discussed in which silica based glasses, ionogels and organogels are functionalized with active catalyst species. These cat~lysts have undergone the hydrogenation of styrene, the enantioselective hydrogenation of geraniol and the transfer hydrogenation ofacetophenone. We report the results of catalytic reactions employing these heterogenized homogenous catalysts comparable in selectivity and conversion to their homogeneous counterparts, yet having ease of separation. and effortless handling conditions equivalent to and (in some cases) better than corresponding heterogeneous catalysts. We also report the negligible metal leaching in our catalyst systems.EThOS - Electronic Theses Online ServiceGBUnited Kingdo