Combined Heterogeneous Catalyst Based on Titanium Oxide for Highly Efficient Oxidative Desulfurization of Model Fuels

Abstract

In this work, new heterogeneous Mo-containing catalysts based on sulfonic titanium dioxide were developed for the oxidation of sulfur-containing model feed. The synergistic effect of molybdenum and sulfonic group modifiers allows for enhancing catalytic activity in dibenzothiophene oxidative transformation, and a strong interaction between support and active component for thus obtained catalysts provides increased stability for leaching. For the selected optimal conditions, the Mo/TiO2-SO3H catalyst exhibited 100% DBT conversion for 10 min (1 wt % catalyst, molar ratio of H2O2:DBT, 2:1; 80 °C). Complete oxidation of DBT in the presence of the synthesized catalyst is achieved when using a stoichiometric amount of oxidizing agent, which indicates its high selectivity. The enhanced stability for metal leaching was proved in recycling tests, where the catalyst was operated for seven oxidation cycles without regeneration with retainable activity in DBT-containing model feed oxidation with hydrogen peroxide under mild reaction conditions. In 30 min of the reaction (H2O2:S = 2:1 (mol), 0.5% catalyst, 5 mL of acetonitrile, 80 °C), it was possible to reduce the content of sulfur compounds in the diesel fraction by 88% (from 5600 to 600 ppm).

New Approach to Ultrafast Oxidative Desulfurization in the Presence of Sulfated Alumina-Based Catalysts

“…As the temperature decreases, a rather sharp drop in DBT conversion occurs (in the presence of both catalysts). This is due to two main factors (Figure C): the first is due to the fact that active peracids are intensively formed under the influence of hydrogen peroxide only at elevated temperatures . The second factor is associated with the adsorption of water and hydrogen peroxide on the acid sites of the catalyst–the higher the temperature, the more intense the desorption of water and hydrogen peroxide, the easier the diffusion of nonpolar DBT into the pores of the catalyst.…”

“…We have previously shown the combination of two types of active centers: Bronsted acid sites and molybdenum compounds have a synergistic effect and can significantly reduce the reaction time. , Thus, the combination of immobilized nicotinic acid with phosphomolybdic acid anchored on SBA-15 allows the complete oxidation of DBT to the corresponding sulfone in just 5 min . The multifunctional role of nicotinic acid has been shown: the carboxylic group is responsible for coordinating the sulfur-containing substrates and the formation of the corresponding peracid.…”

Assessment of Reaction Parameters in the Oxidative Desulfurization Reaction

“…Recent studies have identified five distinct groups of heterogeneous catalysts used in the ODS process: transition metal oxides stabilized, polyoxometalates, ionic liquids, , carbon materials, and porous materials . Transition metal heterogeneous catalysts have drawn significant attention as a result of their suitable Lewis acid sites and excellent catalytic performance in the ODS process. , …”

“…38 Transition metal heterogeneous catalysts have drawn significant attention as a result of their suitable Lewis acid sites and excellent catalytic performance in the ODS process. 39,40 3.1.1. Transition Metal Oxides.…”

Extractive Desulfurization in Microchannel Contactors Using Deep Eutectic Solvents: Optimization Using Central Composite Design (CCD) and Flow Pattern Mapping

“…The major content of the sulfur compounds (such as thiols, sulfides, and disulfides) is removed by HDS technology; however, some refractory sulfur compounds, such as dibenzothiophene (DBT) and its alkylated derivatives, cannot be easily removed by conventional HDS . In order to remove the HDS refractory sulfur compounds effectively, non-HDS methods such as adsorption, oxidation, biodesulfurization, and extractive desulfurization (EDS) have been investigated. , Extractive desulfurization (EDS) is an attractive non-HDS method due to its high capability in the removal of refractory sulfur compounds, its simplicity, and its low energy consumption due to mild operating conditions compared to HDS technology …”