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

Abstract

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.

Oxidative desulfurization of fuel oil catalyzed by a carbon nitride supported phosphotungstic acid based dicationic ionic liquid

“…The chemical shifts of four supported catalysts with different loadings are as follows: 3% [C 2 IJMIM) 2 ]PW 12 O 40 /g-C 3 N 4 : δ = 3.34 (s, 6H, N-CH 3 ), 2.47 (s, H, C-H); 10% [C 2 IJMIM) 2 ]PW 12 O 40 /g-C 3 N 4 : δ = 3.34 (s, 6H, N-CH 3 ), 2.51 (s, H, C-H); 30% [C 2 IJMIM) 2 ]PW 12 O 40 /g-C 3 N 4 : δ = 3.34 (s, 6H, N-CH 3 ), 2.51 (s, H, C-H); and 50% [C 2 IJMIM) 2 ]PW 12 O 40 /g-C 3 N 4 : δ = 3.34 (s, 6H, N-CH 3 ), 2.51 (s, H, C-H). Compared with the results of the 1 H NMR analysis of [C 2 IJMIM) 2 ]PW 12 O 40 in our previous study,27 it was found that only hydrogen in two chemical environments was detected in the 1 H NMR spectra of the supported catalysts, which respectively corresponded to the hydrogen in the nitromethyl group on the imidazole ring of the catalyst and the hydrogen on the adjacent carbon. Moreover, the chemical shifts shift to high field.…”

“…Dicationic ionic liquids (DILs) have attracted much attention in the ODS process due to their large cationic structure and high stability. [23][24][25][26] In our previous research, 27,28 Due to its unique graphite-like layered stacking structure and sp 2 hybrid π-conjugated electron band structure, g-C 3 N 4 has many excellent physical and chemical properties. 29 Moreover, it is simple in preparation, cheap in raw materials, and non-toxic and has good thermal and chemical stabilities.…”

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

“…Hence, many researchers adopted the approaches of multi-stage extraction or extraction coupled with oxidation to perform desulfurization and obtained great results. [48][49][50][51]…”

Catalysts and Processes for H2S Conversion to Sulfur

“…Li et al carried out the oxidative desulfurization of fuel oil for the removal of dibenzothiophene by using imidazole-based polyoxometalate dicationic ionic liquids. Three kinds of catalyst were synthesized and tested under different conditions [8]. The catalytic performance of the catalysts was studied under different conditions by removing the dibenzothiophene from model oil.…”