Molecular Iodine in Ionic Liquid: A Green Catalytic System for Esterification and Transesterification

Abstract

Esterification of carboxylic acids and transesterification of β-ketoesters with alcohols have been developed using a catalytic amount of iodine in polyethylene glycol (PEG) ionic liquid (IL 1000) to afford the corresponding esters in good yields. By simple separation of the ionic-liquid phase containing the iodine, the system of I₂/IL 1000 can be reused several times.

Keywords:

• Esterification
• ionic liquid
• molecular iodine
• transesterification

Notes

^a Isolated yields.

^b The system of I₂/IL 1000 was run for four consecutive cycles.

^c IL 400 was used.

^d IL 2000 was used.

^e IL 4000 was used.

^a All reactions were carried out with 3 mol% of iodine in refluxing toluene for 6 h.

^b Isolated yields.

^a All reactions were carried out with 3 mol% of iodine in refluxing toluene for 6 h.

^b Isolated yields.