Developing a synthetic approach with thermoregulated phase-transfer catalysis: Facile access to metal-mediated living radical polymerization of methyl methacrylate in aqueous/organic biphasic system

摘要

A novel strategy via thermoregulated phase-transfer catalysis (TRPTC) to separating catalyst in aqueous/organic biphasic system has been successfully established in a copper-mediated activators generated by electron transfer for atom transfer radical polymerization (AGET ATRP) of methyl methacrylate (MMA), using a thermoresponsive PEG-supported dipyridyl ligand (PSDL) as the ligand and an alkyl pseudohalogen 2-cyanoprop-2-yl 1-dithionaphthalate (CPDN) as the initiator. The catalyst complex can transfer into the organic phase from initial catalyst aqueous solution at the reaction temperature (90 C) to catalyze the homogeneous polymerization of MMA and then retransfer into the aqueous solution from the organic phase to separate the catalyst from the polymerization solution once cooled to room temperature (25 C) while remaining well-controlled product (PMMA) in organic layer. In addition, the polymerization can be conducted in the presence of a limited amount of air, which not only does not sacrifice the controllability over polymerization but also can recycle the catalyst just by a simple change of the temperatures effectively.