Esterification of acetic acid with butanol: kinetic study and fuzzy modelling using electrochemical parameters

Abstract This study explores the esterification of acetic acid with n -butanol using methanesulfonic acid (MSA) as a homogenous catalyst. The experiments were conducted in a batch reactor, kinetic study has been done using an ideal concentration-based model, and an activity-based model. The activity coefficients for species taking part in the reaction are estimated through the UNIFAC model. The effect of various operating variables including temperature (60–90 °C), reactant molar ratio of n -butanol to acetic acid (1–3), and catalyst loading of (0.5–1.5 wt%) on acetic acid conversion was investigated. Both the kinetic models are able to predict the conversion with high accuracy ( R 2 = 0.99). The conversion of acetic acid has been mapped in terms of electrochemical parameters using electrochemical impedance spectroscopy (EIS). A constant phase element (CPE) coupled with diffusion model has been used for ascertaining the impedance parameters. The impedance parameters obtained on fitting the equivalent circuit have been used for developing a fuzzy inference system (FIS) based on Takagi and Sugeno’s approach. The developed FIS exhibits a higher degree of accuracy in predicting the acetic acid conversion/reaction yield. The results obtained through the developed FIS indicated its use as a soft sensor in esterification industries.