Intensifying long‐chain esterification using double salt ionic liquids: A case study of active tuning strategy

Abstract Despite the significantly enlarged chemical space and enhanced property tunability of double salt ionic liquids (DSILs) as opposed to conventional organic solvents and two‐ion ionic liquids, their applications, particularly in long‐chain esterification and related reactions, still remain scarcely studied. In this work, a systematic exploration to identify DSILs as bifunctional solvents for intensifying long‐chain esterification is conducted and exemplified by the synthesis of isobutyl isobutyrate (IBIBE). After proposing, testing, and actively tuning property criteria based on Brønsted acidity and extractive potential of parent ILs, suitable DSIL candidates are successfully identified as bifunctional solvents. By esterification experiments using the finally screened DSIL, the corresponding IBIBE yield is notably higher than that in the benchmark 1‐butyl‐3‐methylimidazolium hydrogen sulfate ([C 4 MIm][HSO 4 ]). Moreover, the easy accessibility of high‐purity product ester and excellent reusability of DSIL are also experimentally validated. This work offers valuable guidance for developing suitable DSILs as process‐intensifying solvents for diverse applications.