【文章內(nèi)容簡介】 material) able to sustain a chain reaction in such a manner that the rate of reaction increasescritical at or of a point at which a property or phenomenon suffers an abrupt change especially having enough mass alcohol was shown to have a higher reaction rate than transesterification when using the same supercritical alcohol [7]. A benefit of the process is that esters are produced from the FFA. Producing ester from different sources of grease and oil using lipaselipase(lī`pās), any enzyme capable of degrading lipid molecules. The bulk of dietary lipids are a class called triacylglycerols and are attacked by lipases to yield simple fatty acids and glycerol, molecules which can permeate the membranes ..... Click the link for more information.is a viable method, but this involves large volumes of water [7].Table 1 lists Bronsted acidic and basic catalysts, lipase catalysts, and supercritical alcohol catalysts. In regards to Lewis basic and acidic catalysts, there are several examples in the literature [2428].What role can ionic liquids play? Ionic liquids have been used in a large number of chemical reaction types. Examples can be found in the twovolume book by Wasserscheid and Welton [29] and a review on the industrial applications of ionic liquids [30]. The principal reasons for attempting reactions in ionic liquids is that these solvents are involatile except at low pressures and high temperatures [31], and their properties can be designed to suit a particular need (designer solvents) [32]. An example of design is to alter the structure of ionic liquid such that it phase separates from the product of a reaction, making product isolation easier [33]. Another approach is to make either the cationcation(k?t39。ī`?n), atom or group of atoms carrying a positive charge. The charge results because there are more protons than electrons in the cation. ..... Click the link for more information.or anion anion(?n`ī39。?n), atom or group of atoms carrying a negative charge. The charge results because there are more electrons than protons in the anion. or both of the ionic liquids acidic or basic (either Lewis or Bronsted) [34]. Specific examples of ionic liquids which exhibit Bronsted acidity due to functionalized cations include sulfonic acid sulfonic acid(s?lf?n`?k), organic pound containing the functional group RSO2OH, which consists of a sulfur atom, S, bonded to a carbon atom that may be part of a large aliphatic or aromatic hydrocarbon, R, derivatives of the imidazolium cation, ., 4(3methylimidazolium) butanesulfonic acid [35]. This last approach could be used to enable the ionic liquid to catalyze esterification, transesterification, and specifically biodiesel forming reactions. Also, it is possible to design the ionic liquid in such a way that it can be recovered intact at the end of a reaction, thus not creating any ionic liquid waste, and recycled (one of the issues with ionic liquids is that they can be more expensive than some of the simpler catalysts, and somewhat more expensive than conventional solvents).Esterification