A micro reaction-controlled phase-transfer catalyst for oxidative desulfurization based on polyoxometalate modified silica

• Polyoxometalate precursor and organic ammonia were locked in the channel of silica.
• Generated [C16H33(CH3)2NOH]3{PO4[WO(O2)2]4} was soluble and trapped in the channel.
• Dibenzothiophene was oxidized efficiently (H2O2/S molar ratio was 4:1).
• The heterogeneous catalyst was easy for reuse and highly stable.
• Solid phase extraction was used for products (sulfones) separation.

A surfactant polyoxometalate compound [C16H33(CH3)2NOH]3{PO4[WO(O2)2]4} was encapsulated in the channels of silica to compose a micro reaction-controlled phase-transfer system for efficient oxidative desulfurization. It provides enhanced catalytic performance for dibenzothiophene oxidation. Dibenzothiophene (DBT) can be oxidized efficiently at mild conditions (atmospheric pressure, 70 °C, H2O2/S molar ratio is 4:1) with S-conversion near 100%. Furthermore, DBTO2 can be removed via solid phase extraction using silica gel. It provides a strategy to produce near sulfur free motor fuel.

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