The CO2 reaction with alkanolamines has received considerable attention by both academia and industry. Commonly, the formation of the carbamate during the CO2 reaction with primary, secondary, and sterically hindered amines is described by a two-step zwitterion mechanism. Alternatively, a single-step termolecular reaction mechanism can also be used to govern carbamate formation. The experimental kinetic data for several amine-based solvents are consistent with this mechanism, and it can satisfactorily explain fractional-order and higher-order kinetics. However, up to now, the termolecular reaction mechanism has not been properly discussed. Here, this mechanism is described in detail, a simple procedure to estimate the kinetic parameters is outlined, and the termolecular reaction kinetics for various systems comprising individual and mixed amines is reviewed.