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

Design and Synthesis of Amphiphilic Catalyst [C16mim]5VW12O40Br and Its Application in Deep Desulfurization with Superior Cyclability at Room Temperature

Achieving long-term stable deep desulfurization at room temperature and recovering high value-added sulfone products is a challenge at present. Herein, a series of catalysts [C_nmim]₅VW₁₂O₄₀Br (C_nVW₁₂, 1-alkyl-3-methylimidazolium bromide tungstovanadate, n = 4, 8, 16) were presented for the room temperature catalytic oxidation of dibenzothiophene (DBT) and its derivatives. Factors affecting the reaction process, such as the amount of catalyst, oxidant, and temperature, were systematically discussed. C₁₆VW₁₂ showed higher catalytic performance, and 100% conversion and selectivity could be achieved in 50 min with only 10 mg. The mechanism study showed that the hydroxyl radical was the active radical in the reaction. Benefiting from the "polarity strategy", the sulfone product accumulated after 23 cycles in a C₁₆VW₁₂ system, and the yield and purity were about 84% and 100%, respectively.

Preparation of di-[EMIM]CoCl3 Ionic Liquid Catalyst and Coupling with Oxone for Desulfurization at Room Temperature

The intermediate di-[EMIM]Cl was synthesized from methyl imidazole and 1,4-dichlorobutane and then reacted with cobalt chloride at 105 °C to prepare a bi-[EMIM]CoCl3 ionic liquid catalyst. The di-[EMIM]CoCl3 catalyst coupled with oxone to remove sulfur-containing organics in octane. The di-[EMIM]CoCl3 catalyst was characterized by HNMR, FTIR, TG, and SEM–EDS. The dibenzothiophene (DBT) was dissolved in octane to prepare a model oil with an initial sulfur content of 500 ppm. Six grams of the model oil was added. The results showed that the optimal dosages of di-[EMIM]CoCl3, oxone (20 wt%), and [BMIM]BF4 extractant were 1 g, 2 g, and 2 g, respectively. At the optimum temperature of 45 °C, 100% of sulfur was removed after 40 min. After di-[EMIM]CoCl3 was recycled five times, the sulfur removal percentage remained above 91%. The sulfur removal percentages for different sulfur-containing organics followed the order of dibenzothiophene (DBT) > benzothiophene (BT) > 4,6-dimethyldibenzothiophene (4,6-DMDBT). The oxidation product was determined to be DBTO2 by GC–MS analysis, and the oxidation mechanism was discussed. The active oxygen atoms of oxone oxidized DBT to form DBTO, and then persulfate oxidized DBTO to DBTO2 via an identical oxidation mechanism.

Adsorption oxidation desulfurization of model fuel by mesoporous SiO2 supported deep eutectic solvents TBAB/PEG-200

A novel supported deep eutectic solvent (DES) TBAB/PEG-200 was prepared by loading DES TBAB/PEG-200 onto mesoporous silica by the sol–gel method.

Oxidative Desulfurization of Fuel Oil Catalyzed by Carbon Nitride Supported Phosphotungstic Acid Based Dicationic Ionic Liquid

In this study, a novel phosphotungstic acid based dicationic ionic liquid [C2(MIM)2]PW12O40 was successfully prepared and immobilized on graphitic carbon nitride (g-C3N4). The supported catalysts wt% [C2(MIM)2]PW12O40/g-C3N4 (wt=3%, 10%, 30%,...

Synthesis of modified amphiphilic quaternary ammonium silicotungstate and its application in heterogeneous catalytic oxidative desulfurization

Mechanism of amphiphilic quaternary ammonium silicotungstate for oxidative desulfurization.

Catalysts and Processes for H2S Conversion to Sulfur

Hydrogen sulfide is one of the main waste products of the petrochemical industry; it is produced by the catalytic hydrodesulfurization processes (HDS) of the hydrocarbon feedstocks, and it is a byproduct from the sweetening of sour natural gas and from the upgrading of heavy oils, bitumen, and coals [...]

Optimization study on deep extractive oxidative desulfurization with tetrabutylammonium bromide/polyethylene glycol DES

Green, efficient and inexpensive desulfurizing solvents have always been a considerable focus of petroleum desulfurization research. In this study, a series of deep eutectic solvents (DESs) based on tetrabutylammonium bromide (TBAB)/polyethylene glycol 200 (PEG-200) with different molar ratios were synthesized and characterized by Fourier transform infrared spectroscopy and ¹H nuclear magnetic resonance spectroscopy. Dibenzothiophene (DBT) was removed deeply as the classic sulfide in model oil, and H₂O₂ was fully utilized by the new TBAB/PEG-200 desulfurization system in step extractive oxidative desulfurization. The reaction conditions were optimized further, and O/S = 8, DES/oil = 1 : 5, 40 °C and 75 minutes were chosen as the best reaction conditions. Meanwhile, other organic sulfides in crude oil were also removed, and the removal rates of DBT, 4,6-dimethyldibenzothiophene and benzothiophene were 99.65%, 96.71% and 93.52%, respectively. The DES was reused 7 times, and the desulfurization efficiency of the regenerated DES for DBT was maintained at 98.14%. Finally, the possible mechanism of the synergistic effect of two kinds of hydrogen bonds and the oxidant was proposed.

Green, efficient and inexpensive desulfurizing solvents have always been a considerable focus of petroleum desulfurization research.

Catalysts and Processes for H2S Conversion to Sulfur

The hydrogen sulfide (H2S) is one of the main byproducts in natural gas plants, refineries, heavy oil upgraders, and metallurgical processes [...]