Effective Ligandless Pd-containing Catalysts for Triple Bond Hydrogenation and Cross-Coupling in Environmentally Friendly Solvents

Abstract

This study is devoted to the investigation of Pd nanoparticle (NP) formation in polymeric environment of hyper-crosslinked polystyrene (HPS) of MN270 type and study of their catalytic properties in several industrially important catalytic reactions such as Suzuki cross-coupling by the example of 4-bromoanisole and phenylboronic acid and triple bond hydrogenation of acetylenic compounds (2-methyl-3-butyne-2-ol, dehydrolinalool and dehydroisophytol). Influence of Pd precursor nature (chlorine containing salt or palladium acetate) and substrate nature was investigated. HPS-based catalysts containing relatively small Pd NPs (about 4 nm in diameter) were shown to be active and selective (selectivity to target products higher than 98 % and 93 % in case of cross-coupling and hydrogenation) in mild reaction conditions 60oC in environmentally friendly solvents (ethanol and water) at the absence of phase-transfer agents.