International Journal of Thermophysics

, Volume 25, Issue 4, pp 1025–1036

Reaction Kinetics and Critical Phenomena: Saponification of Ethyl Acetate at the Consolute Point of 2-Butoxyethanol + Water


  • Y. W. Kim
    • Department of ChemistryUniversity of Alabama in Huntsville
  • J. K. Baird
    • Department of ChemistryUniversity of Alabama in Huntsville

DOI: 10.1023/B:IJOT.0000038497.48181.11

Cite this article as:
Kim, Y.W. & Baird, J.K. International Journal of Thermophysics (2004) 25: 1025. doi:10.1023/B:IJOT.0000038497.48181.11


The rate of sponification of ethyl acetate by sodium hydroxide was measured near the consolute point of the liquid mixture, 2-butoxyethanol + water. At temperatures far below the lower critical solution temperature, T c, the apparent rate constant obeyed the Arrhenius equation. In the one-phase region just beneath T c, the rate constant decreased below the Arrhenius background, indicating critical slowing down. Because the kinetics of this reaction are second order, the net reaction rate depends upon both (∂ΔG/∂ξ) e and (∂ΔG/∂ξ) e , where Δ G is the Gibbs free energy difference between products and reactants, ξ is the extent of reaction, and subscript “e” refers to chemical equilibrium. On the basis of the Principle of Universality, it is argued that as the temperature approaches T c, both of these thermodynamic derivatives should go to zero, and the net reaction rate should slow down as is actually observed.

2-butoxyethanol critical slowing down kinetics saponification water

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© Plenum Publishing Corporation 2004