Efficient eco-sustainable ionic liquid-polyoxometalate desulfurization processes for model and real diesel

- A recycling desulfurization system using homogeneous polyoxometalates is presented.
- Ionic Liquid acts as sulfur extraction solvent and catalyst immobilization medium.
- Ionic liquid promotes the stability of the catalyst using excess of H2O2.
- Multicomponent model diesel was complete desulfurized after 3 h at 50 °C.
- An efficiency of 80% was achieved to desulfurize a real diesel (S = 2300 ppm).

This work presents a successful recycling system based in homogeneous polyoxometalate catalysts to desulfurize model and real diesels. Various Keggin-type polyoxometates entrapped in a room temperature ionic liquid (RTIL) phase were investigated. The desulfurization process here proposed conciliates efficiently an extraction and an oxidative catalytic process under sustainable and moderate conditions (H2O2 as oxidant, 50 °C). The ionic liquid acts as an extraction solvent and also as an effective immobilization medium for the active homogeneous catalysts. The zinc-polyoxometalates presented high stability and high capacity to be recycled for various consecutive cycles with no loss of desulfurization efficiency. Complete desulfurization of model diesel was achieved at short reaction time (3 h). Under the same experimental conditions, 80% of sulfur was removed from real diesel (Sinitial = 2300 ppm).

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