Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.

Hydrophobic ionic liquids (ILs) based on cations with long alkyl side-chains (e.g. N-octadecyl-N 0 ,N 00 ,N 000trimethylammonium bis(trifluoromethylsulfonyl)imide ([C 18 tma][NTf 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 C, with exceptional enzyme stability (up to 1370 days halflife time at 60 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. Broader contextA clean biocatalytic approach for producing biodiesel using temperature switchable ionic liquid/solid phases as reaction/separation media has been developed. This paper demonstrates a novel property of ionic liquids (ILs) based on cations with long alkyl side-chains (e.g. N-octadecyl-N 0 ,N 00 ,N 000 -trimethylammonium bis(triuoromethylsulfonyl)imide ([C 18 tma][NTf 2 ])) that behave as sponge-like systems for soaking and releasing (wringing) hydrophobic compounds (triolein and methyl oleate). As liquid phases, these ILs are excellent monophasic reaction media for the lipase-catalyzed methanolysis of triolein, resulting in fast and efficient biodiesel synthesis: up to 100% yield in 8 h at 60 C, accompanied by exceptional enzyme stability (up to 1370 days half-life time at 60 C). As solid phases, the reaction mixture can easily be fractionated by iterative centrifugations at controlled temperature into three phases: solid IL, glycerol and pure biodiesel. This represents a straightforward and sustainable approach for producing biodiesel, allowing full recovery and reuse of the biocatalyst-IL system for successive cycles and suitable for scaling-up. The unique properties of hydrophobic ILs, based on cations with long alkyl side chains (e.g. [C 18 tma][NTf 2 ]), allow the combined biotransformation and straightforward separation of the product opening up new opportunities to develop new reaction platforms for green industrial processes.

Different nanostructured supports, based on 1-decyl-2-methyimidazolium cations covalently attached to a polystyrene divinylbenzene porous matrix, were used as carriers to immobilise Candida antarctica lipase B. The suitability of these immobilised lipase derivatives for the synthesis of biodiesel (methyl oleate) by the methanolysis of triolein has been tested in both tert-butanol and supercritical (sc)CO(2) (18 MPa, 45 °C) as reaction media. The use of modified supports with low ionic-liquid loading covalently attached to the main polymeric backbone chains provide structured materials that led to the best biodiesel yields (up to 95 %) and operational stability (85 % biodiesel yield after 45 cycles of 8-4 h) in scCO(2) (45 °C, 18 MPa). The presence of tert-butanol as an inert cosolvent in the scCO(2) phase at the same concentration as triolein was key to avoid poisoning the biocatalyst through the blockage of its active sites by the polar byproduct (glycerol) produced in the biodiesel synthesis.

The synthesis of biodiesel fuel from lipids (vegetable oils and animal fats) has gained in importance as a possible source of renewable non-fossil energy in an attempt to reduce our dependence on petroleum-based fuels. The catalytic processes commonly used for the production of biodiesel fuel present a series of limitations and drawbacks, among them the high energy consumption required for complex purification operations and undesirable side reactions. Supercritical fluid (SCF) technologies offer an interesting alternative to conventional processes for preparing biodiesel. This review highlights the advances, advantages, drawbacks and new tendencies involved in the use of supercritical fluids (SCFs) for biodiesel synthesis.

Registro de acceso restringido Este recurso no está disponible en acceso abierto por política de la editorial. No obstante, se puede acceder al texto completo desde la Universitat Jaume I o si el usuario cuenta con suscripción. Registre d'accés restringit Aquest recurs no està disponible en accés obert per política de l'editorial. No obstant això, es pot accedir al text complet des de la Universitat Jaume I o si l'usuari compta amb subscripció. Restricted access item This item isn't open access because of publisher's policy. The full--text version is only available from Jaume I University or if the user has a running suscription to the publisher's contents.