Biodiesel is produced through a catalytic transesterification of triacylglycerides (e.g., triolein) with alcohols (e.g., methanol). Triacylglycerides and alcohols are not miscible, however, leading to production methods that are inefficient.

Pedro Lozano and co-workers, Universidad de Murcia, Spain, have analyzed the phase behavior of several ionic liquids (ILs) and their ability to dissolve triolein and methanol. 1-Methyl-3-octadecylimidazolium bis(trifluoromethylsulfonyl)imide-based ionic liquid, [C₁₈mim][NTf₂], was shown to provide a homogeneous one-phase system for mixtures having an IL content higher than 30 % (w/w) at 50 and 60 °C

The biocatalytic system, Novozym 435/[C₁₈mim][NTf₂], was shown to yield 96 % biodiesel (methyl oleate) in 6 h. The enzyme/IL system could be reused for seven operation cycles without any loss in IL phase or enzyme activity.

• One-Phase Ionic Liquid Reaction Medium for Biocatalytic Production of Biodiesel
  P. Lozano, J. M. Bernal, R. Piamtongkam, D. Fetzer, M. Vaultier,
  ChemSusChem 2010, 3.
  DOI: 10.1002/cssc.201000244