SBA-15 Modified with Tethered Ionic Liquids Applied in the Esterification of Valeric Acid with Pentanol—Towards Cellulosic Biofuels

Two catalysts are prepared by tethering ionic liquid cation components (1-(propyl-3-sulfonate)-3-(3-trimethoxysilylpropyl) imidazolium) with either chloride or sulphate anions, to the surface of a mesoporous SiO2 material through a condensation reaction. These are characterized using elemental analysis, TGA-MS, FTIR (and D-FTIR), TEM, physisorption and NH3 adsorption (TPD and FTIR), and applied in the valeric acid + pentanol esterification reaction to form the sustainable biodiesel Pentyl Valerate. The material containing the sulfate counter-ion was significantly more active than the chloride analogue.