The Lipase-catalysed Esterification And Transesterification In Ionic Liquid

There are many merits in enzyme-catalyzed reaction of organic synthesis, such as theirmuch milder reaction conditions, friendly environments, quick rate and high selectivity.Although nonaqueous enzymatic reaction workup easily, the conventional organic reactionmedia restrict enzyme activity and stability. Over the past decade, many groups attempted toresolve the problems of enzyme immobility and deactivation in organic solvent. Recentlymany groups was interested in application of room temperature ionic liquid as novel solventsreplace of conventional organic reaction media in enzyme-catalyzed reaction.Room temperature ionic liquids consist of an organic cation and inorganic anion, theions do not pack well and remain liquid at room temperature. They are low-melting (<100 °C),and the properties of ionic liquids largely depend on the cation and anion. Different kind ofenzyme, especially lipase that tolerate organic solvent well, have unusual exhibition in ionicliquid, whose activity is generally comparable with, or better than those observed in organicreaction media. In addition, because of their particular molecule frame the ionic liquid acts asa reservoir for enzyme suspended in them, which could reduce the enzyme deactivation andadvance thermal stability , operational stability , three-dimensional selectivity andenantioseletivity. At present, 1-butyl-3-methylimidazolium tetrafluoroborat and1-butyl-3-methyl-imidazolium hexafluorophosphate were chosen reaction media ofenzymatic reaction in ionic liquid since enzyme's activity and stability were improved inthem.In this article, we investigated the ordinary esterification and transesterification bylipase. Hexane, reversed micelle(AOT/isooctane) and ionic liquid( [bmim][PF6]and[bmim][BF4] ) was selected as reaction media. The conversion oflipase-catalyzed esterification of fatty acid and fatty alcohol in different reaction media has nodistinction. But the conversion of transesterification in ionic liquid.was closed to that inhexane, Furthermore, an important and added advantage is that the lipase –containing mediumcould be recyclable 7 times and that the lipase's activity has no significant decrease;This work has already demonstrated the feasibility of ionic liquid [bmim][PF6] asreaction media for the transesterification and esterification. The activity of CCL in ionic liquid[bmim][PF6] was greater than that in organic solvent. Especially, the results oftransesterification embody the advantage of ionic liquid: the conversion enhanced veryquickly and reaction rates improved rapidly. It is noteworthiness that the lipase could berecyclable 7 times together with [bmim][PF6] and that the lipase's activity has no significantdecrease. [bmim][PF6] might be a popular alternative and recyclable reaction media fortransesterification and esterification.