Catalysis of μ-oxo-bis[porphyriniron(III)] for toluene oxidation with molecular oxygen

Abstract

Toluene oxidation with molecular oxygen as the sole oxidant, and μ-oxo-bis[tetraphenylporphinatoiron(III)] as the catalyst, are reported. Under the reaction conditions of 438 K and 0.8 MPa, the molar total yields for the products benzaldehyde and benzyl alcohol and the turnover number of the catalyst are 4.35% and 21,830 (based on the metal ion), respectively. Compared with the reaction catalyzed by the corresponding monometalloporphyrin TPPFe III Cl, the total yields of the oxidation products and the catalyst turnover number by the dimeric iron porphyrin were almost twice those by the former. A possible reaction mechanism of the toluene oxidation by μ-oxo-bis[tetraphenylporphinatoiron(III)] is proposed.

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

“…28 Hu et al used the complex μ-oxo-bis[tetra-phenylporphinatoiron( iii )] as a catalyst, and 7.4% toluene conversion with 59.0% selectivity to BAL and BOL was achieved. 29 Guo et al reported cobalt tetraphenylporphyrin as a catalyst, and 8.9% toluene conversion with 60% selectivity to BAL and BOL was achieved. 30 Huang et al prepared a chitosan (CTS)-supported Co( ii ) TPP catalyst, and 8.8% toluene conversion with 65.0% selectivity towards BAL and BOL was achieved.…”

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

“…The author also evaluated the effect of peripheral substituents (electron-donating vs. electron-withdrawing), reaction temperature, solvent, and exposure to air on the catalytic activity of the m-oxo heme dimers [60][61][62]. Later, the application of m-oxo heme dimers for direct aerobic oxidation of other hydrocarbons (e.g., cyclopentane, cyclooctane, ethylbenzene or toluene), with the O 2 serving as the terminal oxidant, was investigated [63][64][65]. Guo and coworkers subsequently examined the influence of dioxygen pressure and flow rate in the homogeneous liquid-phase aerobic oxidation of toluene to benzaldehyde, benzyl alcohol, and benzoic acid under conditions similar to those of commercial operations.…”

Comparative study of reactions between µ-nitrido- or µ-oxo-bridged iron tetrasulfophthalocyanines and sulfur-containing reductants

“…The naturally occurring methane mono-oxygenase enzyme (MMO) converts methane to methanol in aqueous solutions under mild conditions. [5][6][7][8][9] In 2009, it was discovered that the μ-nitrido-dimer of iron phthalocyanine catalyzes the low-temperature oxidation of methane by hydrogen peroxide. μ-Oxo-dimers of iron complexes with tetrapyrrole macrocycles (porphyrins and phthalocyanines) have been intensively used in model reactions of hydrocarbon oxidation for a long time.…”