Synthesis of isoamyl hexanoate catalyzed by deep eutectic solvent based on benzyltrimethylammonium chloride: RSM and ANN optimization and kinetics

Abstract

AbstractBackgroundIsoamyl hexanoate is a widely used edible spice. In this paper, the process and kinetics of the esterification of hexanoic acid and isoamyl alcohol to isoamyl hexanoate catalyzed by deep eutectic solvents (DESs) were studied. Several kinds of DESs (BTMAC‐zPTSA) were prepared from benzyltrimethylammonium chloride (BTMAC) and p‐toluenesulfonic acid monohydrate (PTSA) with a molar ratio of z. The synthesis process of isoamyl hexanoate was optimized by response surface methodology and artificial neural network. The effects of process conditions such as the kind and load of catalyst, alcohol/acid ratio and reaction temperature were studied. In the temperature range of 338.15 to 368.15 K, BTMAC‐1.2PTSA was selected as the catalyst, and then the kinetic data and chemical equilibrium composition of the esterification of hexanoic acid with isoamyl alcohol were determined.ResultsAfter optimizing the synthesis process of isoamyl hexanoate using response surface methodology and artificial neural network, the conversion rate of hexanoic acid increased to 92.15%. The esterification reaction kinetics were described using a pseudo‐homogeneous model based on activity, with an average relative deviation of 1.9% and activation energy of 25.79 kJ mol−1. The catalytic performance of catalyst BTMAC‐1.2PTSA remains good after five cycles of use.ConclusionThe established kinetic model has a good predictive effect on the kinetic data for the synthesis of isoamyl hexanoate. The catalyst BTMAC‐1.2PTSA has good stability and recyclability, and has the potential to replace traditional catalysts in the production of isoamyl hexanoate. © 2023 Society of Chemical Industry.