Oxidative Polymerization of 2,6-Xylenol Catalyzed by Insoluble Copper-Polyvinylpyridine Complex

2,6-Xylenol (XOH) was polymerized by the copper-polyvinylpyridine (PVP) chelate in heterogeneous systems. The catalytic characteristics of insoluble Cu-PVP complexes were discussed. Insoluble Cu-PVP complexes underwent relatively rapid exchange of ligands to give catalytically active structures. For example, active CuCl(OH)-PVP complexes were obtained when inactive CuCl₂-PVP complexes were washed with water. XOH was polymerized by the swelled Cu-PVP complex in benzene. After polymerization, the catalyst was readily recovered by filtration in a high yield and the catalyst so recovered could be used repeatedly. The PVP complexes were relatively stable against alkali due to their chelate structure. In alkaline solution the polymerization was accelerated, while side-reactions were suppressed.