Synthesis of Oxygenated Fuel Additive from Waste Biomass Derived Aldehyde using Green Catalyst: An Experimental and DFT Study
Herein, we report a greener and sustainable synthesis of green fuel additive using protic ionic liquid (PIL) catalysts from biomass derived 5-HMF and 1,3-propanediol. The synthesized PIL catalysts were characterized using spectroscopic techniques such as 1H NMR, 13C NMR and UV-visible spectroscopic techniques. PIL Catalyst [IL-SO3H][CF3SO3], gave 99.2% 5-HMF conversion and 86.8% yield of the 5-HMF cyclic acetal in 2.5 h. The time, temperature, and molar ratio of the reactants for the 5-HMF conversion were optimized with the most active catalyst. Further, theoretical DFT calculations were performed for PIL catalyst to calculate ion-pair interaction energies which reveal the activity of the catalyst. From DFT calculation, interaction and dissociation energies of ion-pair of the PILs were determined. Further, the value of the chemical potential (μ) and chemical hardness (η) of PIL were investigated using DFT. Experimentally determined Hammett acidity for the catalysts were found to be in good agreement with the theoretical DFT study.