Solvent-free liquid-phase selective catalytic oxidation of toluene to benzyl alcohol and benzaldehyde over CeO2–MnOx composite oxides

A novel CeO2–MnOx composite oxide was prepared by the improved sol–gel method. The synergistic catalysis of Mn3+/Mn2+ and Ce4+/Ce3+ was responsible for the good catalytic performance in the liquid phase solvent-free selective oxidation of toluene.

(Hydr)oxo-bridged heme complexes: From structure to reactivity

Iron–porphyrins ([Formula: see text] hemes) are present throughout the biosphere and perform a wide range of functions, particularly those that involve complex multiple-electron redox processes. Some common heme enzymes involved in these processes include cytochrome P450, heme/copper oxidase or heme/non-heme diiron nitric oxide reductase. Consequently, the (hydr)oxo-bridged heme species have been studied for the important roles that they play in many life processes or for their application for catalysis and preparation of new functional materials. This review encompasses important synthetic, structural and reactivity aspects of the (hydr)oxo-bridged heme constructs that govern their function and application. The properties and reactivity of the bridging (hydr)oxo moieties are directly dictated by the coordination environment of the heme core, the nature and ligation of the second metal center attached to the (hydr)oxo group, the presence or absence of a linker, and the degree of flexibility around that linker within the scaffold. Here, we summarize the structural features of all known (hydr)oxo-bridged heme constructs and use those to categorize and thus, provide a more comprehensive picture of structure–function relationships.

Hydrocarbon oxidation by iron-porphyrin immobilized on SBA-15 as biomimetic catalyst: role of silica surface

We describe a heterogeneous catalyst containing iron-porphyrins in SBA-15 structures for biomimetic catalysis, correlating surface adsorption/wetting characteristics to oxidation mechanisms.

First industrial-scale biomimetic oxidation of hydrocarbon with air over metalloporphyrins as cytochrome P-450 monooxygenase model and its mechanistic studies

A novel industrial-scale trial for cyclohexane oxidation with air over metalloporphyrins as cytochrome P-450 monooxygenase model was reported. Upon addition of extremely low concentrations (1–5 ppm) of simple cobalt porphyrin to the commercial cyclohexane oxidation system, and decrease of the reaction temperature and pressure about 20 °C and 0.4 MPa respectively, the conversion rate of the cyclohexane oxidation increased from 4.8% to 7.1%, the yield of cyclohexanone raised from 77% to 87%, and a 70,000-ton cyclohexanone equipment set yielded an output of 125,000 tons cyclohexanone. Furthermore, a novel biological-chemical-cycle coupling mechanism was proposed to rationalize the aerobic oxidations of hydrocarbons catalyzed by the metalloporphyrins.