Preparation of [EMIM]DEP/2C3H4O4 DESs and its oxidative desulfurization performance

A series of [EMIM]DEP/nC3H4O4 (n = 1, 2, 3) deep eutectic solvents (DESs) were synthesized by heating and stirring the mixture of 1-ethyl-3-methylimidazolium diethylphosphate ([EMIM]DEP) and propanedioic acid (C3H4O4). [EMIM]DEP/2C3H4O4 was characterized by Fourier transform infrared (FT-IR), 1H nuclear magnetic resonance (1H NMR), and thermogravimetric analysis (TGA). Dibenzothiophene (DBT) in model oil was removed using the DESs as an extractant and catalyst, and H2O2 as an oxidant. The influence parameters of different systems, temperature, n(H2O2)/n(S), dosage of [EMIM]DEP/2C3H4O4, and the sulfide type on desulfurization were investigated. The experimental results show that removal rate of DBT can attach to 98.2%. FT-IR analysis of DBT, DESs, and the mixture (DBT-DESs) show that there is an interaction between DBT and DESs.