Highly efficient sulfonated styrene resins and optimization for the ethanolysis of furfuryl alcohol to ethyl levulinate

Abstract

Different types of sulfonated styrene resins (SSRs) were applied to the ethanolysis of furfuryl alcohol (FA) to ethyl levulinate (EL). The catalytic performance results showed that the SSR-2 catalyst prepared through sulfonation at 60 °C for 5 h demonstrated the best activity with 100% FA conversion and 97% EL selectivity under the reaction conditions of 126 °C, 2.2 h, and 0.12 g catalyst dosage, which was dramatically superior to the previous results. Notably, the SSR-2 catalyst maintained excellent stability over five cycles, which was attributed to the synergistic effect of the stable, three-dimensional crosslinked network structure of the styrene-based resins and the appropriate SO₃H groups, effectively alleviating the leaching problem of the active groups. Innovatively, Response Surface Methodology (RSM) was used to optimize the reaction conditions of FA ethanolysis over the SSR-2 catalyst and the catalyst dosage was identified as the most crucial factor for the production of EL, focusing on the effects of reaction temperature, reaction time and catalyst dosage on EL selectivity. Moreover, the predicted EL selectivity of 97.4% obtained from RSM matched well with the experimental value of 97% under the optimal reaction conditions, paving the way for catalyst engineering in EL production from FA ethanolysis.