How to produce biodiesel easily using a green biocatalytic approach in sponge-like ionic liquids

• Published in: Energy & environmental science Vol. 6; no. 4; pp. 1328 - 1338
• Main Authors: Lozano, Pedro, Bernal, Juana M., Sánchez-Gómez, Gregorio, López-López, Gregorio, Vaultier, Michel
• Format: Journal Article
• Language: English
• Published: 2013
• ISSN: 1754-5692; 1754-5706
• DOI: 10.1039/c3ee24429f

Hydrophobic ionic liquids (ILs) based on cations with long alkyl side-chains (e.g. N-octadecyl-N',N'',N'''-trimethyl ammonium bis(trifluoromethylsulfonyl)imide ([C sub(18)tma][NTf sub(2)])) are switchable ionic liquid/solid phases with temperature that behave as sponges. As liquid phases, they are excellent monophasic reaction media for lipase-catalyzed methanolysis of triolein, resulting in fast and efficient biodiesel synthesis, e.g. up to 100% yield in 8 h at 60 degree C, with exceptional enzyme stability (up to 1370 days half-life time at 60 degree C). As solid phases, the reaction mixture can easily be fractionated by iterative centrifugations at controlled temperature into three phases, i.e. solid IL, glycerol and pure biodiesel. A straightforward and sustainable approach for producing biodiesel has been developed, allowing full recovery and reuse of the biocatalyst-IL system for successive cycles and suitable for scaling-up.