Quaternary ammonium functionalized Fe₃O₄@P(GMA-EGDMA) composite particles as highly efficient and dispersible catalysts for phase transfer reactions

This work describes the synthesis and catalytic behavior of magnetic nanoparticle supported quaternary ammonium phase transfer catalysts Fe₃O₄@P(GMA-EGDMA)N⁺(CH₃)₃OH^- (MQPTCs). The MQPTCs prepared by compositing P(GMA-EGDMA) on Fe₃O₄ magnetic nanoparticles via seeded emulsion polymerization and quaternized by trimethylamine were characterized by SEM, TEM, FTIR, TGA and VSM, and core-shell structured MQPTCs with an exchange capacity of 1.14 mmol g^-1 were obtained. The catalytic activity of the MQPTCs was evaluated via the investigation of the efficiency of the conversion of benzyl alcohol and benzyl bromide into dibenzyl ether. In addition, the influences of the concentration of the catalysts and species of the catalysts (different exchange capacities of the MQPTCs) on conversion were studied in detail. The results demonstrated that the MQPTCs showed high efficiency with a conversion of 95% in only 6 h that was comparable with small molecule PTCs, and excellent reusability with a conversion of 94.1% after being reused 8 times.