The enthalpy and entropy of activation for ethyl acetate saponification



The saponification of ethyl acetate was measured by conductimetry at different temperatures within a batch reactor. A new mathematical model for obtaining concentration profiles from conductivity was presented and used for reaction-kinetics' determination. The Arrhenius parameters (A, Ea) showed good agreement with the previously published values. Basic transition-state theory was used for obtaining the Gibbs energy (ΔG‡), the enthalpy (ΔH‡), and the entropy (ΔS‡) of activation. The low enthalpy of activation and negative entropy of activation were consistent with a reaction pathway when forming a transition-state complex. The suggested mechanism involves OH, acting as a general base for removing proton from one of the hydroxide hydrating water, placed directly between it and the ester. The nucleophile from the water then attacks at the electrophilic C of the ester, breaking the π bond, and creating a tetrahedral intermediate. © 2012 Wiley Periodicals, Inc. Int J Chem Kinet 44: 692–698, 2012

This article was published online on 24 January 2012. An error was subsequently identified. This notice is included in the online and print versions to indicate that both have been corrected on 16 July 2012.