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A desulfurization process, based on the formation and subsequent precipitation of S-alkylsulfonium salts using alkylating agents (CH3I and AgBF4), has been applied to the desulfurization of catalytic-cracked gasoline (CCG). The desulfurization reactivity of each sulfur compound (thiol, disulfide, benzothiophene, tetrahydrothiophene, and thiophenes) in n-decane solution, as a model gasoline, was compared with that obtained from actual CCG. The sulfur compounds in CCG are methylated by the addition of the alkylating agents under moderate conditions and are removed as the precipitates of the corresponding S-alkylsulfonium salts. By employing this new process, the sulfur content of the CCG was decreased from 100 ppm to less than 30 ppm. The benzothiophene in CCG was found to be the most difficult compound to desulfurize, whereas the thiophenes were the most difficult compounds for the model gasoline. Although the olefin concentration was decreased significantly following desulfurization, the resulting CCG dem...

A novel desulfurization process for light oils has been investigated, based on the precipitation of S-alkylsulfonium salts produced by the reaction of sulfur-containing compounds with alkylating ag...

A desulfurization process, based on photoinduced electron-transfer oxidation using 9,10-dicyanoanthracene (DCA) and organic two-phase extraction, has been applied to the desulfurization of catalytic-cracked gasoline (CCG). Sulfur-containing compounds (thiol, disulfide, and thiophenes), in acetonitrile solution, are photooxidized by photoirradiation, at wavelengths of λ>400 nm in the presence of DCA, to form highly polarized compounds (sulfoxide, sulfone, and sulfate anion), and these compounds do not distribute into the CCG. Thus, when CCG and acetonitrile solution are mixed and are photoirradiated with DCA, the sulfur-containing compounds are extracted into the acetonitrile phase and are photooxidized, thus providing the successive removal of sulfur from CCG to acetonitrile under moderate conditions. In this way, the sulfur content of CCG is reduced successfully from 100 ppm to less than 30 ppm. The large quantity of olefins contained in the CCG is minimally photooxidized, owing to their small fluorescence quenching rate with DCA, and thus the desulfurized CCG has the same high octane number as that of the feed CCG.

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...

A visible light-induced desulfurization process for light oil, effected by electron-transfer photooxygenation and liquid–liquid extraction, allows the deep desulfurization of light oil under moderate conditions and without hydrogen.