Monodispersed poly(4-vinylpyridine) spheres supported Fe(III) material: An efficient and reusable catalyst for benzylic oxidation

A novel ferric chloride immobilized poly(4-vinylpyridine) (P4VP) catalyst was developed via a coordination chemistry-based approach. The pyridine moiety of poly(4-vinylpyridine) spheres functioned as the nitrogen donor to bind iron ions, as well as to decrease the amount of pyridine used in the catalytic reaction system. The monodispersed catalyst was well dispersed in the organic solvent during the catalytic procedure, taking advantage of its nanomorphology and uniform size. The catalytic activity of various monodispersed catalysts based different mass fractions of the divinylbenzene (DVB) was investigated, meanwhile the capacities of supported Fe(III) in the various catalysts were also discussed. The P4VPDVB10%-Fe(III) catalyst exhibited high catalytic activity in the benzylic oxidation of benzylic methylenes and secondary benzylic alcohols. It was easily separated from the reaction system and reused several times without obvious degradation of catalytic activity. Moreover, leaching tests suggested that the as-synthesized P4VPDVB10%-Fe(III) catalyst was a true heterogeneous catalyst without significant metal leaching.