Skip to main content
U.S. flag

An official website of the United States government

Official websites use .gov
A .gov website belongs to an official government organization in the United States.

Secure .gov websites use HTTPS
A lock ( ) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.

Thermodynamics of the Lipase Catalyzed Transesterifation of (-)-Menthol and Dodecyl Dodecanoate in Organic Solvents

Published

Author(s)

Yadu D. Tewari

Abstract

The thermodynamics of the lipase-catalyzed transesterification reaction (-)-menthol(sin) + dodecyl dodecanoate(sin) = (-)-menthyl dodecanoate(sin) + 1-dodecanol(sin)have been studied. Equilibrium measurements were performed as a function of temperature with n-heptane, toluene, and 2,2,4-trimethylpentane as solvents. The results of the equilibrium measurements were used to calculate the standard molar Gibbs energy δfG m, enthalpy δfH m, and entropy δfS m changes for the above reaction in these three solvents at the temperature T = 298.15 K. The values of the δfG m and δfH m in these solvents ranged, respectively, from 1.5 to 2.6 kJ mol-1 and from 0.2 to 4.0kJ mol-1. The (n-hexane + water) partition coefficients of the reactants and products were also determined at T - 298.15 K. A thermochemical cycle calculation was then used to calculate a value for the equilibrium constant K = 2.4 0.7) x 10-3 and δfG m = (14.9 0.7) kJ mol-1 for the above reaction in water. However, the average value of the equilibrium constant for reaction (1) in the organic solvents is remarkably constant, namely = 0.372 (estimated standard deviation of the mean = 0.014). Thus, the thermodynamics of this reaction in water are substantially different than in the organic solvents studied herein.
Citation
Journal of Molecular Catalysis B-Enzymatic
Volume
9
Issue
1-3

Keywords

(-)-menthol, (-)menthyl dodecanoate, 1-dodecanol, dodecyl dodecanoate, equilibrium constants, lipase, organic solvents, partition coefficients, solubility

Citation

Tewari, Y. (2000), Thermodynamics of the Lipase Catalyzed Transesterifation of (-)-Menthol and Dodecyl Dodecanoate in Organic Solvents, Journal of Molecular Catalysis B-Enzymatic (Accessed March 2, 2024)
Created March 20, 2000, Updated February 17, 2017