Transition to Carbon Materials: The Effect of Support Nature on the Catalytic Properties of Anderson-Type Polyoxometalate in Aerobic Oxidation of Sulfur-Containing Compounds

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 1methylimidazole 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.

Sustainable synthesis of thiosulfonates and disulfides by molybdenum-catalyzed selective oxidation of thiols

“…In this regard, much progress has been achieved in the selective oxidation of thioethers to sulfoxides and sulfones. 9 However, the selective catalytic oxidation of thiols to S–S bond-containing compounds remains a challenge due to over-oxidation and S–S bond cleavage (Scheme 1b). 10…”

Amphiphilic Catalysts Comprising Phosphomolybdic Acid Fastened on MIL-101(Cr): Enabling Efficient Oxidative Desulfurization under Solvent-Free and Moderate Reaction Conditions

“…Also, larger organic cations with long carbon chains would lead to desirable mass transfer capabilities for sulfides in fuel oils, benefiting the improvement of reaction activity . Simultaneously, polyoxometalate (POM) anions, with abundant catalytic sites existing in their terminal groups, bridging coordination, and metal ions, often exhibit a good catalytic ability for many oxidants to oxidize numerous substrates . Thus, POM-based ILs (POM-ILs), consisting of long carbon chain cations and catalytic POM anions, might be promising catalysts for the advanced oxidation of substrates in oily solvents .…”