Isotropic Liposomal Microreactor for Catalytic Oxidative Desulfurization

The efficient removal of refractory sulfides from fuels to achieve clean oil is a primary research focus in the petrochemical industry. This study introduces extraction and catalytic oxidation desulfurization (ECODS) as a technique for effective desulfurization. A cross-linking strategy was employed to construct structurally stable isotropic microreactors based on ionic liquid (IL)-modified liposomes (poly[MimA₁₁, A₁₁][heteropolyanions]), where exposed imidazolium cations anchor catalytic heteropolyanions (e.g., [PW₁₂O₄₀]^3-) to ensure active site accessibility. In this interfacial catalytic reaction, the microreactor resembles an emulsified droplet with a spherical surface, significantly enhancing the catalytic interface. Additionally, the isotropic imidazolium cations of spherical vesicles provide the equivalent driving force for the attachment of heteropolyanions (such as [PW₁₂O₄₀]^3- and [PMo₁₂O₄₀]^3-), ensuring full exposure of active sites and reducing mass transfer resistance. The optimized poly[MimA₁₁, A₁₁][PW₁₂O₄₀] catalyst achieved complete dibenzothiophene (DBT) removal within 1.5 h and retained 92.4% efficiency after six cycles, demonstrating exceptional activity and recyclability. The morphology, structure, and properties of the microreactors were characterized, and optimal reaction conditions were established. Building on this foundation, the removal performances across various systems and sulfur-containing targets were assessed, thereby confirming the structure-activity relationship of this type of microreactor. Furthermore, the desulfurization mechanism was inferred from the identified oxidation products. Overall, this isotropic poly[MimA₁₁, A₁₁][heteropolyanion] demonstrates excellent desulfurization performance and holds significant potential for broad applications.