Kinetics and thermodynamic analysis of levulinic acid esterification using lignin-furfural carbon cryogel catalyst

The synthesis of ethyl levulinate, a fuel additive, by catalytic esterification of levulinic acid with ethanol over carbon cryogel has been investigated. The carbon cryogel catalyst, coupled with a large surface area and strong acidity, has been identified as an effective carbon-based catalyst for obtaining high ethyl levulinate yield of 86.5 mol%. The pseudo-homogeneous kinetic model is adopted to evaluate the different reaction orders. The first-order pseudo-homogeneous model is considered most suitable (R² > 0.98) while the selection of kinetic model is also clarified and supported by the linearity of the parity plot. The activation energy of the esterification reaction is estimated to be 20.2 kJ/mol. Based on the thermodynamic activation parameters, the reaction is classified as endergonic and more ordered. The results from this study could provide valuable information for reactor modeling and simulation purposes in the future.