INFLUENCE OF THE AROMATIC POLYMERIC MATRIX TYPE ON STABILITY OF NANOSIZED PALLADIUM CATALYSTS IN SUZUKI REACTION

Abstract

This work is devoted to the study of the influence of the type of polymeric matrix of hyper-crosslinked polystyrene on activity and stability of palladium catalysts of Suzuki cross-coupling. The use of the hyper-crosslinked polystyrene functionalized with tertiary amino groups was shown to be promising in terms of ensuring of the catalyst stability during recycles, but in order to achieve 100 % conversion of aryl halide ( 4 - bromanisole) the use of strong excess of phenylboronic acid and of a base is required. The catalyst based on non-functionalized hyper-crosslinked polystyrene had higher activity and allowed achieving complete conversion of 4 - bromanisole during the reaction under mild conditions ( 70°С, ethanol and water mixture is in the ratio of 5:1 as a solvent) while using 1,5 - fold excess of phenylboronic acid. However, strong adsorption of the cross-coupling product in a hydrophobic polymeric matrix was found to be a disadvantage of such a system.

Keywords

• suzuki cross-coupling
• palladium
• catalyst
• nanoparticles
• hyper-crosslinked polystyrene