Transition to Carbon Materials: The Effect of Support Nature on the Catalytic Properties of Anderson-Type Polyoxometalate in Aerobic Oxidation of Sulfur-Containing Compounds
E. A. Eseva, Maxim O. Lukashov, Л. А. Куликов, Oleg Yu. Grafov, Alina F. Bikbaeva, A. V. Akopyan
Abstract
New highly effective heterogeneous catalysts representing immobilized Anderson-type polyoxometalate (POM) supported on the hydrophobic surface of a porous aromatic framework PAF-30 were modified with triethylamine or 1-methylimidazole for the aerobic oxidation of sulfur-containing substrates. The catalysts were characterized using FT-IR, solid-state 13 C NMR, N 2 adsorption–desorption isotherms, BET, SEM, TEM, EDX, TGA, XRF, and XPS analyses. The activity of synthesized catalysts in the aerobic oxidation of a model fuel was investigated. It was shown that the immobilization of POM on the surface of PAF-30 modified with 1-methylimidazole can significantly increase the efficiency of the process of aerobic oxidation of dibenzothiophene (DBT) due to the uniform dispersion of the active phase on the support. The effect of the catalyst dosage, reaction temperature, and the nature of the substrate on the air oxidation process was studied. Optimal reaction conditions were selected, allowing us to achieve 100% DBT conversion: 0.54 mg/mL of PAF-30-Imi-POM catalyst, 130 °C, 1 h, 650 rpm, air flow rate 6 L/h. In addition, it has been demonstrated that the catalyst PAF-30-Imi-POM retains high activity for at least 5 cycles of reuse with the use of intermediate regeneration.