Cu/P(4-PVP) stereochemistry in tetralin liquid-phase oxidation: I. Effect of the CuCl2/P(4-PVP) on selectivity

Cu/P(4-PVP) catalyst was used as catalyst for oxidation of tetralin in liquid phase. The catalyst was prepared by reaction of a Cu(II) salt with a 4-vinylpyridine-co-divinylbenzene polymer receptor and characterized by solid 1H and 13C NMR, XPS, FTIR, ESR spectroscopies, and by chemical reaction with pure tetralin. That information was used to gain insight into the stereochemistry of the active site needed to orient the reaction toward tetralone production. It was found that the Cu coordination with the pyridine was critical in influencing the peroxy-radical catalytic reaction, and that polyvinylpyridine was able to limit the autothermal oxidation. The active center is postulated to be based on a (Cu2+–Cu+)-pyridine distorted tetrahedric structure that is modified by the oxireduction reactions with tetralin.