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Liquid-phase Oxidation of Hydrocarbons with Molecular Oxygen. I. The Effects of Metal Ions and Their Ligands on Product Distribution in the Oxidation of Tetralin in Acetic Acid

1978; Oxford University Press; Volume: 51; Issue: 5 Linguagem: Inglês

10.1246/bcsj.51.1404

1348-0634

Fujio Mizukami, Juichi IMAMURA,

Metal-Catalyzed Oxygenation Mechanisms

Abstract Metal-ion catalyzed oxidation of tetralin and metal-ion catalyzed decomposition of α-tetralin hydroperoxide (THP) were carried out in acetic acid in both the presence and absence of an additive. It was found that the rate-determining step in the oxidation of tetralin is the decomposition of THP. The results also suggest that the decomposition of THP with cobalt catalysts proceeds by the inner-sphere mechanism. In the oxidation of tetralin catalyzed by first-transition-metal ions, excepting vanadium, cobalt showed the highest activity and the lowest selectivity of hydroperoxide, and chromium showed the highest ratio of α-tetralone to α-tetralol (On/Ol). The order of the activities of metal acetates in producing oxidation is in agreement with that of the activities of metal acetates in producing decomposition. Such agreement was also found for Co(acac)3, Cr(acac)3, Mn(acac)2, and Fe(acac)3 catalysts. For oxidation with Co(OAc)2·4H2O and Cr(OAc)3, the product distributions were examined for various conversions of tetralin. In the both cases, the On/Ol ratios increase with increasing tetralin conversion. However, the mechanisms responsible for the increase in the On/Ol ratio appear to be different.