Kinetic Study and Model Assessment for n‑Butyl Levulinate Production from Alcoholysis of 5‑(Hydroxymethyl)furfural over Amberlite IR-120

Alkyl levulinates such as n-butyl levulinate (BL) can play an important role in the fuel sector. Classically, BL is produced from the esterification of levulinic acid, but the butanolysis (or alcoholysis) of sugars requires less stages. The industrialization of this process requires the development of process flow diagrams and thus the knowledge of reaction kinetics and thermodynamics. To the best of our knowledge, there are no kinetic models for the production of BL from sugar butanolysis over heterogeneous catalysts. The kinetics of sugar monomer butanolysis is complex over heterogeneous catalysts due to several side reactions, for example, esterification and humin productions. Hence, developing a kinetic model strategy is vital by primarily focusing on the butanolysis of 5-HMF over Amberlite IR-120. The butanolysis of 5-(hydroxymethyl)­furfural (5-HMF) is the crucial step for the production of BL. The effects of temperature, catalyst, and 5-HMF loadings and catalyst deactivation on the kinetics of the different species were investigated. Then, different kinetic models were developed and tested by cross-validation. Special attention was given to vary widely the reaction temperature, catalyst, and 5-HMF loadings. To increase the accuracy of the estimation stage, independent experiments of levulinic and formic acid esterification, side products of 5-HMF dehydration, were included. It was found that the developed model with more reaction steps and by considering the reaction of humin production from 5-HMF as first order was the most reliable model.