Ultrasound‐Assisted Synthesis of Isopropyl Lactate Using Ion‐Exchange Resin Catalyst: Statistical Optimization and Mechanistic Analysis

ABSTRACT Isopropyl lactate is a crucial intermediate in pharmaceutical manufacturing and has a wide range of applications across various industries. This study investigates the ultrasound‐assisted synthesis of isopropyl lactate via esterification using ion‐exchange resin catalysts, with two objectives: (i) statistical optimization of process parameters and (ii) elucidation of the mechanism underlying sonication‐induced enhancement of reaction kinetics and ester yield. Two cationic ion‐exchange resins, Amberlyst 15 and Amberlite IR 120, were evaluated. Statistical optimization under mechanical agitation revealed that chemical variables had a significant influence on esterification performance, whereas physical factors were found to be insignificant. Under optimized conditions, maximum isopropyl lactate yields of 15.39% and 10.79% were achieved with Amberlyst 15 and Amberlite IR 120, respectively. The application of ultrasound at 35 kHz and a ∼10% duty cycle significantly enhanced esterification, increasing yields to 22.97% (49.25% enhancement) for Amberlyst 15 and 18.44% (70.8% enhancement) for Amberlite IR 120. Reaction regime analysis indicated intrinsic (surface‐reaction‐controlled) kinetics rather than solid–liquid mass‐transfer limitation. Furthermore, a decline in ester yield under elevated static pressure highlighted the critical role of transient cavitation in enhancing ultrasound‐driven kinetics. These findings demonstrate the effectiveness of ultrasound in intensifying ion‐exchange‐resin‐catalyzed esterification and provide mechanistic insights for process optimization.