OPTIMIZATION OF PALLADIUM-BASED SUPPORTED LIQUID-PHASE CATALYSTS IN THE HECK REACTION

Heck reactions using sulphonated triphenylphosphine palladium complexe s have been carried out using a supported liquid-phase catalysis syste m in a batch reactor. The catalyst complex is held in solution in a po lar, hydrophilic film supported upon porous grass beads whilst reactan ts and products are restricted to a nonmiscible solvent phase. Several factors in the preparation of the supported catalyst were investigate d with the aim of ensuring good assembly, distribution, and immobilisa tion of the catalyst complex across the surface of the beads. The thic kness of the hydrophilic film upon the porous glass beads was varied. The hydrophilic nature of the ligand complex was studied using mono- a nd trisulphonated sodium and lithium salts of triphenylphosphine. The effects of level of catalyst loading and ligand/catalyst ratio upon le aching and activity were also examined. These factors have been examin ed to develop a better understanding of the catalysis occurring in sup ported liquid-phase systems.