Ivan V. Kozhevnikov

Sulfonated hierarchical H-ZSM-5 monoliths were synthesized via ice-templating as solid acid catalysts for biodiesel production.

In recent years, due to the rapid growth of mankind’s demand for energy, harmful gases (SOx) produced by the combustion of sulfur-containing compounds in fuel oil have caused serious problems to the ecological environment and human health. Therefore, in order to solve this hidden danger from the source, countries around the world have created increasingly strict standards for the sulfur content in fuel. Adsorption desulfurization technology has attracted wide attention due to its advantages of energy saving and low operating cost. This paper reviewed the latest research progress on various porous adsorption materials. The future challenges and research directions of adsorption materials to meet the needs of clean fuels are proposed.

Dehydration of i-PrOH is used in academic research as a test reaction to probe the acid properties of solid acid catalysts. Also, it has practical importance for the utilization of surplus acetone produced by the Hock process for the combined manufacturing of phenol and acetone as well as for the production of propene from renewable resources and waste. This study demonstrates the excellent performance of polyoxometalate acid catalysts comprising silica-supported Keggin-type heteropoly acids H₃PW₁₂O₄₀ and H₄SiW₁₂O₄₀ for gas-phase i-PrOH-to-propene dehydration at ambient pressure. These catalysts show similar efficacies, giving an i-PrOH conversion and propene selectivity of 96.8 and 99.7% for 25%HPW/SiO₂ and 97.1 and 99.4% for 25%HSiW/SiO₂ in a fixed-bed reactor at 120 °C, a relevant-to-practice i-PrOH partial pressure of 15 kPa and a contact time W/F = 27 g h mol⁻¹ (GHSV = 900 mL g⁻¹ h⁻¹). The catalysts are stable, resisting deactivation for at least 24 h time on stream. The HPA/SiO₂ catalysts are superior to aluminosilicate zeolites such as H-mordenite, HZSM-5 and HY for i-PrOH-to-propene dehydration in terms of i-PrOH conversion, propene selectivity and catalyst stability.

Amphiphilic hybrid catalysts were prepared by modifying [SMo₁₂O₄₀]²⁻ with tetrabutylammonium bromide (TBAB), 1-butyl-3-methylimidazole bromide (BMIMBr) and octadecyl trimethyl ammonium bromide (ODAB), respectively. The prepared catalysts were characterized by IR, XRD, SEM, TG and XPS. The desulfurization performance of the catalysts was investigated in model oil and actual diesel using hydrogen peroxide (H₂O₂) as an oxidant and acetonitrile as an extractant. All catalysts exhibited favorable activity for removing sulfur compounds at room temperature. Dibenzothiophene (DBT) can be nearly completely removed using SMo₁₂O₄₀²⁻-organic catalysts within a short reaction time. For different sulfur compounds, the [TBA]₂SMo₁₂O₄₀ catalyst showed a better removal effect than the [BMIM]₂SMo₁₂O₄₀ and [ODA]₂SMo₁₂O₄₀ catalyst. The [TBA]₂SMo₁₂O₄₀ dissolved in extraction solvent could be reused up to five times in an oxidative desulfurization (ODS) cycle with no significant loss of activity. The [BMIM]₂SMo₁₂O₄₀ performed as a heterogeneous catalyst able to be recycled from the ODS system and maintained excellent catalytic activity. The catalysts showed a positive desulfurization effect in real diesel treatment. Finally, we described the ODS desulfurization mechanism of DBT using SMo₁₂O₄₀²⁻-organic hybrid catalysts. The amphiphilic hybrid catalyst cation captures DBT, while SMo₁₂O₄₀²⁻ reacts with the oxidant H₂O₂ to produce peroxy-active species. DBT can be oxidized to its sulfone by the action of peroxy-active species to achieve ODS desulfurization.

For ultra-deep desulfurization of diesel fuel, this study applied the ultrasound-assisted catalytic ozonation process to the dibenzothiophene (DBT) removal process with four Keggin-type heteropolyacids (HPA) as catalysts and acetonitrile as extractant. Through experimental evaluations, H₃PMo₁₂O₄₀ was found to be the most effective catalyst for the oxidative removal of DBT. Under favorable operating conditions with a temperature of 0 °C, H₃PMo₁₂O₄₀ dosage of 2.5 wt.% of n-octane, and ultrasonic irradiation, DBT can be effectively removed from simulated diesel. Moreover, the reused catalyst exhibited good catalytic activity in recovery experiments. This desulfurization process has high potential for ultra-deep desulfurization of diesel.

2,5-Dimethyltetrahydrofuran (DMTHF) is deoxygenated to n-hexane with >99% selectivity at mild conditions (90 °C, 1 bar H₂ pressure, fixed-bed reactor) in the presence of the bifunctional metal-acid catalyst Pt–CsPW comprising Pt and Cs_2.5H_0.5PW₁₂O₄₀ (CsPW), an acidic Cs salt of Keggin-type heteropoly acid H₃PW₁₂O₄₀. Addition of gold to the Pt–CsPW catalyst increases the turnover rate at Pt sites more than twofold, whereas the Au alone without Pt is not active. The enhancement of catalyst activity is attributed to PtAu alloying, which is supported by STEM-EDX and XRD analysis.