Synthesis of metallophthalocyanine end-capped polymers and their catalytic activity for the copolymerization of CO2 and propylene oxide

Abstract

A series of metallophthalocyanine end-capped poly(arylene ether sulfone)s containing zinc were synthesized from reduced phenolphthalein by an improved method. The molecular structure of zinc metallophthalocyanine-containing polymer was confirmed by Fourier-transform spectroscopy, wide-angle X-ray diffraction technique, UV-visible spectra, and ¹H-NMR spectra. The zinc metallophthalocyanine-containing polymer was found to be soluble in some solvents, and the colored polymer showed maximum visible absorption at 665 nm. Copolymerization between carbon dioxide and propylene oxide (PO) was performed using the zinc metallophthalocyanine end-capped poly(arylene ether sulfone) as a catalyst. This is the first report to describe the use of metallophthalocyanine-containing polymer as a polymer-supported catalyst to activate carbon dioxide. Catalytic activity (30 g-polymer/g catalyst) was achieved by optimizing the PO/catalyst ratio. NMR measurement revealed that the synthesized copolymer from carbon dioxide and PO had an alternating structure. Thermal properties of the copolymer were determined by thermogravimetric analysis, and the results demonstrated that the copolymer exhibited a high glass transition temperature of 35 °C and decomposition temperature of 247 °C.