Journal of Molecular Catalysis A-Chemical, Vol.180, No.1-2, 277-284, 2002
Palladium-based supported liquid phase catalysts: influence of preparation variables on the activity and enhancement of the activity on recycling in the Heck reaction
Supported liquid phase catalysts (SLPC) were prepared using a porous silica, ethylene glycol, palladium acetate, and triphenylphosphine trisulfonate sodium salt (TPPTS). The SLPC samples prepared were used for Heck reaction of iodobenzene and butyl acrylate with triethylamine base in toluene and the influence of catalyst preparation conditions was examined. The rate of reaction depends on the concentration of palladium-TPPTS complexes in the dispersed phase of ethylene glycol but not on the quantity of the dispersed liquid used. The SLPC sample can be easily separated by simple filtration and it is recyclable; interestingly, the rate of reaction is promoted on the repeated runs, due to the formation and accumulation of Et3NHI adduct in the dispersed phase. (C) 2002 Elsevier Science B.V. All rights reserved.