Enzyme-mediated epoxidation of methyl oleate supported by imidazolium-based ionic liquids

Abstract

Abstract In the present manuscript we describe and discuss the use of hydrophobic and hydrophilic ionic liquids (ILs) as efficient supports to the enzyme-catalyzed epoxidation of biodiesel. The use of nine different lipases in three different ILs (BMI.PF 6 , BMI.NTf 2 and BMI.BF 4 ) gave high biodiesel conversion rates in short reaction times using hydrogen peroxide (30%, v / v) as the epoxidation agent. A drastic behavior change is observed by altering the media from a hydrophobic IL to a hydrophilic IL. For instance, the use of Amano A. lipase (from Aspergillus niger ) in hydrophilic BMI.BF 4 yielded the epoxidized compound in 89% in the first reaction hour, and in the mean time, hydrophobic BMI.PF 6 yielded the same product in 67%. The use of other lipases resulted in the desired epoxidized derivative and also in the 1,2-diol as a result of a reversible epoxy ring-opening promoted in the reaction media. Conversions and selectivities depended on the nature of the IL, on reaction time and on the selection of the lipase enzyme.