Preparation and oxidation desulfurization performance of zirconium oxychloride based ternary deep eutectic solvent

A zirconium oxychloride based ternary deep eutectic solvent (DES) was prepared by simply heating mixture of ethylene glycol, p-toluenesulfonic acid and octahydrate zirconium oxychloride. The successful synthesis of deep eutectic solvents was verified using Fourier transform infrared spectroscopy (FT-IR) and nuclear magnetic resonance hydrogen spectroscopy (¹H NMR). The acidity and viscosity were tested using UV-visible absorption spectroscopy and rotary viscometer, respectively. The extraction-oxidation desulfurization system was composed of hydrogen peroxide as the oxidant, deep eutectic solvent as the extractant and catalyst. The effects of the composition of the deep eutectic solvent, reaction temperature, oxygen sulfur ratio, solvent oil ratio, and different sulfides on the desulfurization rate were investigated. The experimental results showed that the desulfurization rates of dibenzothiophene (DBT), 4,6-dimethyldibenzothiophene (4,6-DMDBT), and benzothiophene (BT) simulated oil were 100%, 92.2%, and 60%, respectively, under the optimal reaction conditions of a molar ratio of 1:10:10 between zirconium oxychloride, ethylene glycol, and p-benzenesulfonic acid components, 50 ℃, a solvent oil ratio of 1∶5, and an oxygen sulfur ratio of 8. After repeated use of the deep eutectic solvent for 5 times, the desulfurization rate could still reach 96.2%. The mechanism of oxidative desulfurization was explored.