A novel process for gasoline desulfurization based on extraction with ionic liquids and reduction by sodium borohydride

• The factors that influenced desulfurization efficiency were investigated.
• The reaction routes of model sulfur compounds were proposed.
• ILs maintained their original structures after regeneration.
• Desulfurization reaction by the ERDS process fitted the pseudo-first-order kinetics.
• The ERDS process could be used as a promising method for gasoline desulfurization.

A novel integrated process of extraction with ionic liquid (IL) and reductive desulfurization by sodium borohydride (NaBH4) was presented for gasoline desulfurization. The factors that influenced desulfurization efficiency were investigated and desulfurization efficiency reached more than 97% for model gasoline and more than 93% for real gasoline. The components of model gasoline after desulfurization were analyzed by gas chromatography/mass spectrometry (GC/MS) and the reaction routes of model sulfur compounds were proposed. The contents of sulfur, boron and nickel in aqueous solutions were analyzed by Chinese standard method or inductively coupled plasma (ICP). Furthermore, the structures of original and recycled ILs were analyzed by nuclear magnetic resonance (NMR) and the desulfurization performance of recycled ILs was investigated. Results indicated that ILs maintained their original structures after regeneration. Finally, desulfurization kinetics was also probed and results showed that desulfurization reactions of both model sulfur compounds and real gasoline could be treated as pseudo-first-order reactions.

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