Transesterification

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transesterification

[¦trans·e¦ster·ə·fə′kā·shən]
(organic chemistry)
Conversion of an organic acid ester into another ester of that same acid.

Transesterification

 

the general name for the processes of alcoholysis (1), acidolysis (2), and ester (RCOOR’) interchange (3):

(1) RCOOR’ + R”OH ⇄ RCOOR” + R’OH

(2) RCOOR’ + R”COOH ⇄ R”COOR’ + RCOOH

(3) RCOOR’ + R”COOR”’ ⇄ RCOOR’” + R”COOR’

The catalysts of transesterification are acids (HCl, HBr, and H3PO4), BF3, and salts of Zn and Co. A shift in the equilibrium toward the right is usually achieved by distillation of the more volatile alcohol (R’OH), acid (RCOOH), or ester.

Transesterification is widely used in preparative organic chemistry and the chemical industry. Thus, bis-β-hydroxyethyl terephthalate, which yields polyethylene terephthalate upon heating to 275°–290°C under vacuum, is obtained from dimethyl terephthalate and ethylene glycol. Transesterification is one of the industrial methods of producing polycarbonates.

References in periodicals archive ?
Further, the n-hexane present in the reaction mixture was removed from transesterified canola oil on rotary evaporator under vacuum to get the concentrated product.
Variables affecting the yield of fatty esters from transesterified vegetable oils.
The formulation optimized by the experimental design was transesterified with sodium methoxide and sodium hydroxide to evaluate whether the reaction mechanism by different catalysts affected the characteristics of biodiesel.
To analyze fatty acids, total lipids were transesterified according to the ISO methodology (1978).
Oil (500 g) was dried over 20 g anhydrous sodium sulphate, filtered, transferred to 100 mL conical flask, 1% Lipozyme IM-60 (Rhizopus miehei Novozyme) was added, flask was sealed with double layer of wax, transesterified at 60 [degrees]C for 24 h at 200 rpm on an electric hot plate cum magnetic stirrer and followed by filtration to remove the enzymes (Abdulkarim et al.
It is found that the feedstocks with high FFAs could not be transesterified with the commercially available alkaline catalyst transesterification process.
Then, an aliquot of 10 [micro]L of the transesterified sample was dissolved in 1000 [micro]L of dichloromethane, and the sample was injected, in duplicate, into a gas chromatograph coupled with a mass spectrometer (GC/MS).
Cyclohexane/1-Butanol and n-Hexane was transesterified using conventional two step method.
Likewise, algal oil was transesterified using ethanol, 1-propanol, 2-propanol, 1-butanol, 1- pentanol, 1-hexanol and benzyl alcohol to produce the corresponding esters i.
The product of the acid-pretreatment was transesterified with alkali catalyst and methanol (0.