Determination of Thermodynamic Properties for the Esterification of Levulinic Acid with 1‑Butene

The thermodynamic equilibrium of the liquid phase esterification of levulinic acid (LA) with 1-butene (1B) to obtain sec-butyl levulinate (SBL) was studied. Equilibrium experiments were performed in a batch reactor at 2.5 MPa in the temperature range of 363–393 K using Amberlyst-15 as the catalyst. The thermodynamic equilibrium for the side reactions (i.e., isomerization of 1B to trans-2-butene, isomerization of trans-2-butene to cis-2-butene, and esterification of LA with these isomers) was also studied. The thermodynamic properties of the reaction were determined experimentally and compared to theoretical estimations and reported literature values. The enthalpy and entropy changes of the esterification reaction with 1B at 298.15 K were estimated to be −(32.9 ± 1.6) kJ/mol and −(70 ± 4) J/(mol·K), respectively. As for the SBL thermodynamic properties, it was found that the liquid phase enthalpy change of formation and entropy at 298.15 K were −(737.1 ± 0.3) kJ/mol and (423 ± 3) J/(mol·K), respectively.