Optimisation of palladium-based supported liquid-phase catalysts in the Heck reaction

Heck reactions using sulphonated triphenylphosphine palladium complexes have been carried out using a supported liquid-phase catalysis system in a batch reactor. The catalyst complex is held in solution in a polar, hydrophilic film supported upon porous grass beads whilst reactants and products are restricted to a nonmiscible solvent phase. Several factors in the preparation of the supported catalyst were investigated with the aim of ensuring good assembly, distribution, and immobilisation of the catalyst complex across the surface of the beads. The thickness of the hydrophilic film upon the porous glass beads was varied. The hydrophilic nature of the ligand complex was studied using mono- and trisulphonated sodium and lithium salts of triphenylphosphine. The effects of level of catalyst loading and ligand/catalyst ratio upon leaching and activity were also examined. These factors have been examined to develop a better understanding of the catalysis occurring in supported liquid-phase systems.