Approximation function for the direct calculation of rate constants and Gibbs activation energies of enantiomerization of racemic mixtures from chromatographic parameters in dynamic chromatography

An approximation function for enantioselective dynamic chromatography of ra cemic mixtures of interconverting enantiomers has been derived that allows the direct calculation of enantiomerization rate constants (k(1) and k(-1)) and Gibbs activation energies of enantiomerization, DeltaG(#), from chroma tographic parameters, i.e., retention times of the enantiomers A and B (t(R )(A) and t(R)(B)), peak widths at half height (w(A) and w(B)) and the relat ive plateau height (h(plateau)), without computer simulation. The reaction rate constants of enantiomerization, k(-1), obtained with this approximatio n function, have been validated by comparison with a simulated dataset of 1 5 625 chromatograms. The mean, standard deviation and confidence interval s how a high correlation between the approximated and simulated rate constant s. The average deviation from the Gibbs activation enthalpy of enantiomeriz ation, DeltaG(#), has been estimated to be as small as about +/-0.11 RT. (C ) 2001 Elsevier Science BN. All rights reserved.