Kinetics of the esterification between lactic acid and isoamyl alcohol in the presence of silica gel‐supported sodium hydrogen sulphate

Abstract

AbstractThe esterification reaction between isoamyl alcohol and lactic acid was studied over silica gel‐supported sodium hydrogen sulphate (NaHSO4 · Silica). The influences of the external mass transfer, internal mass transfer, reaction temperature, catalyst loading, and initial reactant molar ratio were investigated. Kinetic experimental data of this esterification reaction obtained at different temperatures (343–378 K) were correlated with three models (the pseudo‐homogeneous (PH), Eley‐Rideal (ER), and Langmuir‐Hinshelwood (LH) model). The UNIFAC method was employed to estimate the activity coefficients when the non‐ideal thermodynamic behaviour of the reaction mixture was considered. The results show that the ER model is more appropriate for predicting the dynamic data of an esterification reaction. It was found that water and isoamyl alcohol were more strongly adsorbed onto the surface of NaHSO4 · Silica than lactic acid and isoamyl lactate, by comparing the adsorption equilibrium constants of different components existing in the reaction. The activation energy and standard enthalpy of the reaction were found to be 54.1 and −6.27 kJ mol−1, respectively.