CO2-alkanolamine reaction kinetics:: A review of recent studies

Alkanolamines are the most popular absorbents used to remove CO2 from process gas streams. Therefore, the CO2 reaction with alkanolamines is of considerable importance. The aim of this article is to provide an overview on the kinetics of the reaction of CO, with aqueous solutions of alkanolamines. The various reaction mechanisms that are used to interpret experimental kinetic data - zwitterion, termolecular and base-catalyzed hydration - are discussed in detail. Recently published data on reaction kinetics of individual amine systems and their mixtures are considered. In addition, the kinetic behavior of several novel amine-based solvents that have been proposed in the literature is analyzed. Generally, the reaction of CO, with primary, secondary and sterically hindered amines is governed by the zwitterion mechanism, whereas the reaction with tertiary amines is described by the base-catalyzed hydration of CO2.