A Thermodynamic and Time Course Study of the Lipase-Catalyzed Transesterification of Benzyl Alcohol and Butyl Acetate in Supercritical Carbon Dioxide Media

Published

August 16, 2004

Author(s)

Yadu D. Tewari, T. Ihara, Karen W. Phinney, M P. Mayhew

Abstract

The time course and thermodynamics of the lipase-catalyzed transesterification reaction (benzl alcohol + butyl acetate = benzyl acetate + 1-butanol) has been studied in supercritical carbon dioxide (SCCO₂), n-hexane, toluene, and neat media (no solvent added) at the temperature T = 303.15 K. The time course data show that the rate of reaction in SCCO₂ media is significantly higher than in the other solvents. In addition, the pressure dependence on the reaction quotient of the reaction was investigated over the pressure range p= 8 MPa to p = 20 MPa at T = 303.15 K. The equilibrium constant of the above reaction has been measured as a function of temperature (T=318.15 K) at p = 10.0 MPa. The equilibrium constant, standard molar gibbs energy {Δ}_rG _m, enthalpy {Δ}_rH _m, and entropy {Δ}_rS ^ changes for the above reaction at the temperature T = 298.15 K are: K = 0.238 0.020, {Δ}_rG _m = (3.56 0.22) kJ mol^-1, {Δ}_rH _m = (2.1 5.2) kJ mol^-1, and {Δ}_rS _m = (4.9 17) J K^-1 mol^-1. The advantages of the use of supercritical carbon dioxide as a solvent for enzyme-catalyzed reactions are discussed.

Citation

Journal of Molecular Catalysis B-Enzymatic

Volume

30

Issue

3-4

Pub Type

Journals

Keywords

1-Butanol, benzyl acetate, benzyl alcohol, butyl acetate, equilibrium constant, lipase, rate of reaction, supercritical carbon dioxide, thermodynamics

Citation

Tewari, Y. , Ihara, T. , Phinney, K. and Mayhew, M. (2004), A Thermodynamic and Time Course Study of the Lipase-Catalyzed Transesterification of Benzyl Alcohol and Butyl Acetate in Supercritical Carbon Dioxide Media, Journal of Molecular Catalysis B-Enzymatic (Accessed April 24, 2024)