Catalytic C-C coupling of furanic platform chemicals to high carbon fuel precursors over supported ionic liquids

Abstract

Imidazolium-based ionic liquid (IL) catalysts with different anions (Cl-, HSO4-, and CF3SO3-) were covalently anchored to the surface of fibrous silica (FS) by using alkyl chains as a linker. The prepared catalysts were applied for the C-C coupling reactions of 2-methylfuran (2-MF) with levulinic acid (LA), angelica lactone (AL), and ethyl levulinate (EL) to synthesize high carbon fuel precursors. The hydrophilic nature of FS supported IL catalyst having bisulfate anion was suitable for the self C-C coupling reaction of 2-MF and the reaction of 2-MF with LA. FS supported IL catalyst having triflate anion (FS-ILCF3SO3) exhibited high conversion and selectivity for the target fuel precursors from the C-C coupling reaction of 2-MF with AL and EL. The increased solubility, tunable acidity, and hydrophilicity/hydrophobicity of FS-ILHSO4 and FS-ILCF3SO3 promise a sustainable catalyst system. Supported ILs make the transformation processes greener and more efficient for large-scale production of biomass-derived fuel precursors.