Catalytic activity of immobilized metalloporphyrins prepared by synchronously synthesizing and immobilizing porphyrins on polymeric microspheres

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Abstract

A novel route to immobilize metalloporphyrins on polymeric supports was put forward, and it is the way to synchronously synthesize and immobilize porphyrins on polymeric microspheres, followed by metal salt coordination reaction. Copolymeric microspheres (GMA/MMA) of glycidyl methacrylate (GMA) and methyl methacrylate (MMA) were prepared, and then via the ring-opening reaction of the epoxy groups on GMA/MMA microspheres, parahydroxybenzaldehyde (HBA) was bond onto the microspheres, obtaining the modified microspheres HBA-GMA/MMA. Subsequently, the Adler reaction between solid-liquid phases was carried out with HBA-GMA/MMA microspheres and pyrrole as well as benzaldehyde derivate in a solution as coreactants. As a result, it was successfully realized to synchronously synthesize and immobilize porphyrin on the surfaces of GMA/MMA microspheres, resulting in three porphyrin-immobilized microspheres, PP-GMA/MMA (PP: phenyl porphyrin), CPP-GMA/MMA (CPP: 4-chlorophenyl porphyrin) and NPP-GMA/MMA (NPP: 4-nitrophenyl porphyrin). Further, the coordination reaction of these immobilized porphyrins with cobalt salt was conducted, obtaining three supported cobalt porphyrin catalysts, CoPP-GMA/MMA, CoCPP-GMA/MMA and CoNPP-GMA/MMA. The catalytic properties of these supported mettaloporphyrin catalysts were examined in the catalytic oxidation of ethylbenzene to acetophenone by dioxygen. The experimental results indicate: (1) the prepared three solid catalysts are effective in the catalytic oxidation of ethylbenzene to acetophenone by dioxygen; (2) for these polymer-supported metalloporphyrin catalysts, some factors, such as the substitute species on phenyl ring in the macrocycle, the immobilization density of metalloporphyrin and the added amount of the catalyst in the reaction system, affect the catalytic activity greatly; (3) the prepared supported metalloporphyrin catalysts have fine recycle and reuse property. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

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