Addition reactions of aliphatic acids with olefins to give corresponding esters have been investigated using SO3H-functionalized ionic liquids as dual catalyst–solvent. The isolation of the desired products could be achieved via simple decantation and ionic liquids could be reused continuously after dried in vacuum (5–12 mmHg) at ca. 80 ◦C.

★★★☆☆ Y. Gu et al. / Journal of Molecular Catalysis A: Chemical 212 (2004) 71–75.