ON THE KINETICS BETWEEN CO2 AND ALKANOLAMINES BOTH IN AQUEOUS AND NON-AQUEOUS SOLUTIONS .1. PRIMARY AND SECONDARY-AMINES

The reaction between CO//2 and primary and secondary alkanolamines (DEA and DIPA) has been studied both in aqueous and non-aqueous solutions (ethanol and n-butanol) at various temperatures. Reaction kinetics have been established by chemically enhanced mass transfer of CO//2 into the various solutions. The experiments were performed in a stirred vessel operated with a horizontal interface which appeared to the eye to be completely smooth. The reaction can be described with the zwitterion-mechanism. Literature data on the reaction rates can be correlated fairly well with this mechanism. As all amines react with CO//2 in a reversible way, and the mass transfer models used for the interpretation of the experimental data neglect this reversibility and take only the forward reaction rate into account, the influence of the reversibility is studied. With the aid of numerical mass transfer models the experimental method with its underlying assumptions have been verified and the applicability and the limits of this method were determined.