Polyoxometalate Dicationic Ionic Liquids as Catalyst for Extractive Coupled Catalytic Oxidative Desulfurization

Wettability is an important factor affecting the performance of catalytic oxidative desulfurization. In order to develop an efficient catalyst for the extractive coupled catalytic oxidative desulfurization (ECODS) of fuel oil by H2O2 and acetonitrile, a novel family of imidazole-based polyoxometalate dicationic ionic liquids (POM-DILs) [Cn(MIM)2]PW12O40 (n = 2,4,6) was synthesized by modifying phosphotungstic acid (H3PW12O40) with double imidazole ionic liquid. These kinds of catalysts have good dispersity in oil phase and H2O2, which is conducive to the deep desulfurization of fuel oil. The catalytic performance of the catalysts was studied under different conditions by removing aromatic sulfur compound dibenzothiophene (DBT) from model oil. Results showed that [C2(MIM)2]PW12O40 had excellent desulfurization efficiency, and more than 98% of DBT was removed under optimum conditions. In addition, it also exhibited good recyclability, and activity with no significant decline after seven reaction cycles. Meanwhile, dibenzothiophene sulfone (DBTO2), the only oxidation product of DBT, was confirmed by Gas Chromatography-Mass Spectrometry (GC-MS), and a possible mechanism of the ECODS process was proposed.

Insight into the oxidative desulfurization of high-sulfur petroleum coke under mild conditions: a journey of vanadium-substituted Dawson-type phosphotungstic acid

High-sulfur petroleum coke (HSPC), that is a by-product from slag oil in the coking process of refining, shows versatility values in practical applications and, however, concentrates the majority of organic sulfur. Herein, we design and construct a highly effective CTAB@HPA composites to be explored for the catalytic oxidative desulfurization of HSPC under mild conditions using hydrogen peroxide as the oxidant and 1-butyl-3-methylimidazole tetrafluoroborate ionic liquid as the extractant. The results demonstrate that the sulfur content of HSPC could be strikingly reduced from 4.46 wt% to 2.48 wt% under 60 °C and atmospheric pressure, and that the organic sulfur in HSPC is mainly oxidized to sulfoxide, sulfone and sulfate, which latter can be directly separated from petroleum coke. Moreover, the effect of reaction conditions on the desulfurization performance of HSPC as well as the catalytic oxidation reaction kinetic of HSPC desulfurization was systematically investigated. Furthermore, a mechanism for the oxidative desulfurization of HSPC over CTAB@HPA catalysts was proposed. Therefore, this work provides new insight into how to construct active catalysts for the desulfurization of HSPC under mild conditions.

Catalytic oxidative desulfurization of model fuel utilizing functionalized HMS catalysts: characterization, catalytic activity and mechanistic studies

In this study, a novel Fe(ii) porphyrin conjugated amino modified HMS catalyst was synthesized and characterized by BET, XRD, TEM, SEM, and UV-vis techniques.