Stopped‐flow investigations of the reaction kinetics of carbon dioxide with some primary and secondary alkanolamines in aqueous solutions

Abstract

AbstractThe reaction kinetics of carbon dioxide with four alkanolamines of industrial importance (MEA, DGA, DEA, and DIPA) have been investigated with the aid of the stopped‐flow technique, allowing the determination of rate constants for carbamates formation. The constants obtained for MEA at 20°C and 25°C are in good agreement with recent literature data. The kinetic behavior of DGA was found to be almost identical to that of MEA.The rate constants obtained for DIPA at 25°C (54 M−1 s−1) is half as large as that for DEA (110 M−1 s−1). The former one is satisfactorily compared with the recent values proposed by Blauwhoff et al. Activation energies have also been obtained for DEA (23.2 kJ mol−1) and for DIPA (58.7 kJ mol−1) and their mechanistic implications are discussed in relation with the relevanceof a rate‐determining proton transfer step in the process of carbamate formation.