Oxidative-extractive deep desulfurization of gasoline by functionalized heteropoly acid catalysts

Abstract

A series of functionalized heteropoly acid catalysts with two PEG chains and an Anderson-type polyoxoanion IMo₆O₂₄⁵⁻ have been in situ synthesized, and applied for catalytic oxidative desulfurization coupling with extraction (oxidative-extractive desulfurization, OEDS). Two PEG chains endow the catalyst with a good extracting ability for sulfur compounds, particularly, their corresponding oxidative products. The oxidation and extraction can be performed simultaneously. No additional extracting agent is added after oxidation. The mechanism of OEDS is proposed. The effect factors for OEDS of model gasoline with H₂O₂ and O₂ as oxidants are respectively investigated, and the optimum conditions are respectively obtained. The H₂O₂ OEDS system is more efficient, rapid and has low energy consumption. It just takes several tens of minutes under the mild conditions to achieve the complete removal of dibenzothiophene (DBT), benzothiophene (BT) and thiophene in model gasoline. The novel H₂O₂ OEDS system has been also applied for the desulfurization of real gasoline. The vast majority of sulfides in real gasoline are removed after OEDS, and the content of sulfur from 110 ppm can be reduced to 10 ppm. Moreover, the functionalized heteropoly acid catalyst has showed good recyclability.