A novel catalyst containing palladium nanoparticles supported on poly(2-hydroxyethyl methacrylate)/CMK-1: Synthesis, characterization and comparison with mesoporous silica nanocomposite

摘要

A novel catalyst containing palladium nanoparticles supported on poiy(2-hydroxy ethyl methacrylate)/CMK-l (Pd-PHEMA/CMK-1) was prepared, and its application was investigated as a heterogeneous catalyst in Heck coupling reaction. PHEMA/CMK-1 was prepared by in situ polymerization method and used as a support for palladium nanoparticles obtained through the reduction of palladium acetate by hydrazine hydrate. The structural and morphological characterizations of Pd-PHEMA/CMK-1 nanocomposite were carried out using XRD, FT-IR, BET, TGA, XPS, UV-vis, SEM and TEM techniques. This catalytic system exhibited good activity in cross-coupling reactions of aryl iodides, bromides and also chlorides with olefinic compounds in Mizoraki-Heck reactions in short reaction time and high yields. The catalytic activity of this purely organic hybrid catalyst was compared with Pd-PHEMA/MCM-48 to clarify the advantages of mesoporous carbon on mesoporous silica as support. The results showed that the activity and reusability of Pd-PHEMA/CMK-1 was much higher than Pd-PHEMA/MCM48 in Heck reaction.