Transesterification esters

General Preparations of Esters General Cleavage of Esters Transesterification Enzymatically Cleavable Esters Heptyl, 381... 

The majority of publications on transesterification catalyzed by solid acids have focused on the reaction of 3-keto esters. Transesterification provides an alternative route to synthesize these kinds of esters since direct preparation from P-keto acids is not a good option given that they can easily undergo decarboxylation. Table 11 provides a review of results in the literature relating to the transesterification of P-keto esters with alcohols. 

Alcoholysis of nitriles, of ortho and thio ortho esters (transesterification), and of halides is the most common method of preparing the ortho ester functional groups (see Eqs. 2-7). A less practical method is the addition of alcohols to ketene acetals. The latter method is used only when the other methods are not found applicable to the synthesis of specially substituted mixed ortho esters. 

Alcoholysis of Carboxylic Esters. Transesterification Alkoxy-de-alkoxylation... 

Alternative reactions employ coupling reagents such as DCC (Steglich Esterification), preformed esters (transesterification), carboxylic acid chlorides or anhydrides. These reactions avoid the production of water. Another pathway for the production of esters is the formation of a carboxylate anion, which then reacts as a nucleophile with an electrophile (similar reactions can be found here). Esters may also be produced by oxidations, namely by the Baeyer-Villiger oxidation and oxidative esterifications. 

Index Entries Supercritical methanol biodiesel methyl esters transesterification methyl esterification. 

Index Entries Supercritical alcohol biodiesel fatty acids alkyl ester transesterification alkyl esterification. 

Aston [141] selected for the preparation of butyl esters transesterification with the aid of2N KOH in /7-butanol (5 min at room temperature). He evaluated the analyses of fats and oils by computer using a Fortran program. 

Substitution of one alkoxy group for another in an ester. Transesterification can take place under either acidic or basic conditions, (p. 1006)... 

Interesterification (INES) is the exchange of acyl radicals between an ester and an acid (aci-dolysis), an ester and an alcohol (alcoholysis), or an ester and an ester (transesterification), and can be random, directed, or enzymatic. The process has been called intraesterification if an exchange of positions occurs within the same molecule, and randomization if exchange occurs between molecules.44,48 The principles can be used to position fatty acids on mole-... 

The observation that Ln(III) ions can catalyze phosphate ester transesterification, hydrolysis, and RNA cleavage (27) has prompted... 

Rice detoxin A/-Acetyl-t-phenylalanine esters Transesterification nr 9... 

The synthesis of aliphatic poly(carbonate-co-ester)s with about 1 1 molar ratio of the ester-to-carbonate repeat units was reported by CALB-catalyzed transesterification among diethyl carbonate, a diester, and a diol. Molecular weight Mw values reached 59000 at a reaction temperature of 90 °C. A carbonate-ester transesterification reaction between poly(butylene carbonate) and poly(butylene succinate) was also catalyzed by CALB at 95 °C to result in a block copolymer [57]. 

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