Enzyme-mediated epoxidation of methyl oleate supported by imidazolium-based ionic liquids
2011
Silva, Wendylene S.D. | Lapis, Alexande A.M. | Suarez, Paulo A.Z. | Neto, Brenno A.D.
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.PF₆, BMI.NTf₂ and BMI.BF₄) 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.BF₄ yielded the epoxidized compound in 89% in the first reaction hour, and in the mean time, hydrophobic BMI.PF₆ 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.
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