Functionalized Ionic Liquid-Catalyzed 1-Feruloyl-sn-glycerol Synthesis

Feruloyl Glycerol (FG) is a potential antioxidant and UV absorbing ingredient in food and cosmetic industries. Transesterifications of ethyl ferulate (EF) with glycerol to synthesize FG were performed using different functionalized ionic liquids (1-butylsulfonic-3-methylimidazolium tosylate, [BSO₃HMIM]TS; 1-propylsulfonic-3-methylimidazolium tosylate, [PSO₃HMIM]TS; 1-butylsulfonic-3-methylimidazolium trifluoromethanesulfonate, [BSO₃HMIM]OTF; 1-butylsulfonic-3-methylimidazolium hydrogen sulfate, [BSO₃HMIM]HSO₄; N-methylimidazolium hydrogen sulfate, [HMIM]HSO₄; 1-butyl-3-methylimidazolium hydroxide, [BMIM]OH; 1-butyl-3-methylimidazo tetrachloride molysite, [BMIM]FeCl₄; and 1-hexyl-3-methylimidazo tetrachloride molysite, [BMIM]FeCl₄) as catalysts, respectively. High EF conversion (98.0 ± 1.5 %), 1-FG (1-feruloyl-sn-glycerol) yield (88.7 ± 1.1 %) and reaction selectivity for 1-FG (90.5 ± 2.1 %) were obtained using [BSO₃HMIM]TS as catalyst. The activation energy (E ₐ), the Michaelis–Menten kinetic constant (K ₘ), and the maximum initial reaction rate (v ₘₐₓ) of the transesterification are 65.9 ± 3.3 kJ/mol, 1.8 ± 0.1 mol/L, and (1.6 ± 0.4) × 10⁻² mol/(L min), respectively. Effects of catalyst loading, reaction temperature, and the molar ratio of EF to glycerol on EF conversion and reaction selectivity for 1-FG (1-FG yield/EF conversion) were also investigated.