Visible Light-Induced Deep Desulfurization Process for Light Oils by Photochemical Electron-Transfer Oxidation in an Organic Two-Phase Extraction System

Abstract

A novel deep desulfurization process for light oils, based on visible light-induced electron-transfer oxidation using 9,10-dicyanoanthracene (DCA) in an organic two-phase liquid−liquid extraction system, has been investigated. Sulfur-containing compounds, when dissolved in acetonitrile, are successfully oxidized by photoirradiation at wavelengths of λ > 400 nm in the presence of DCA, to form highly polarized compounds, which do not distribute into the nonpolar light oil. When light oil and acetonitrile are mixed and are photoirradiated with DCA, the sulfur-containing compounds are extracted successively and are photooxidized in the acetonitrile phase. In this way, a deep desulfurization is achieved: the sulfur content in light oil being reduced from 0.18 wt % to less than 0.005 wt %. The DCA and the aromatic hydrocarbons in the acetonitrile are able to be recovered by the addition of water, followed by extraction with n-hexane. The DCA distributed into the light oil is strongly adsorbed by silica gel and can then be desorbed into the acetonitrile aqueous solution to be reused for further desulfurization. An overall desulfurization procedure is developed, with the data obtained showing that the proposed process is satisfactory for application to the deep desulfurization for light oil.

Photocatalytic oxidative desulfurization of dibenzothiophene under simulated sunlight irradiation with mixed-phase Fe2O3 prepared by solution combustion

“…This corresponds to 90.7% sulfur removal, which is lower compared with that of the model oil. The result agrees with other photocatalytic desulfurization research, 11,15,16 where two conflicting factors emerged. On one hand, the diesel contains two-ring aromatics, such as naphthalene (NP), which subdues the photoreaction of DBT since the triplet energy of NP is inferior than that of DBT.…”

“…Their works include the study on product identification and the effect of photosensitizer benzophenone on sulfur removal. [12][13][14][15][16] To improve sulfur removal, researchers also used TiO 2 as photocatalyst [17][18][19][20][21][22] because of its nontoxicity, chemical and photochemical stability, low cost, and excellent photocatalytic activity. 23,24 Above mentioned studies were all performed by UV light irradiation because the sulfur-containing compounds cannot be photodegraded itself under visible light.…”

Measurement and correlation of liquid–liquid equilibria and partition coefficients of benzothyophene and benzothyophene 1,1-dioxide for acetonitrile+n-octane system

“…5. Calculated liquid-liquid equilibria for acetonitrile (1) + n-octane (2) and + n-decane (2) systems.…”

“…Oxidative desulfurization in acetonitrile biphasic system [1][2][3], proposed in recent years, can oxidize the unreactive sulfur compounds in the hydrodesulfurization. The polar benzothiophenes and dibenzothiophenes, which are major sulfurcontaining compounds in fossil fuels, are extracted into the polar acetonitrile phase and oxidized.…”

Analysis of Long-Side-Chain Alkylaromatics in Crude Oil for Evaluation of Their Fate in the Environment

“…The photochemical decomposition of alkylbenzothiophenes and alkyldibenzothiophenes in diesel oil has been studied for the development of desulfurization techniques (26,27), and methylbenzothiophenes were shown to be oxidized to 2-sulfobenzoic acid via oxidation of the methyl group and cleavage of the thiophene ring (28).…”