Simultaneous Characterization of Reaction Kinetics and Enthalpy by Calorimetry Based on Spatially Resolved Temperature Profile in Flow Reactors

Abstract

Characterizing the Gibbs energy of activation and the enthalpy of reactions typically requires repeated sampling. In this study, a new calorimetric reaction-characterization technique was developed for thermokinetic analysis in a flow reactor. The method was used to simultaneously determine the Gibbs energy of activation from the reaction kinetics and the enthalpy of reaction by fitting the thermal model equation to the spatially resolved temperature profile obtained on a flow reactor. This procedure was verified and comparatively assessed with conventional analytical methods using a family of peptide syntheses as model reactions. The thermal model equation closely fitted the acquired temperature profile. The calculated Gibbs energies of activation agreed closely with the values determined from product yield-time trends obtained using several reactants at different temperatures. The calculated reaction enthalpy was similar to the values obtained from quantum chemical calculations. The findings suggest that spatial regression calorimetry can simultaneously extract more reaction characteristics than conventional calorimetry.