Molecular interactions between amine and carbonate species in aqueous solution: kinetics and thermodynamics

摘要

Post combustion capture, PCC, of CO₂ from the flue gas stream of coal fired power stations is an attractive proposition for the reduction of CO₂ output into the atmosphere. PCC based on reversible absorption by aqueous amine solution is probably the most advanced technology. Thus the investigation of the chemistry of CO₂ absorption by such solutions is of crucial importance. A critical reaction is the formation of carbamates. There is a vast literature on this process but it is mainly based on empirical reaction mechanisms. In this contribution we present a molecularly correct mechanism for carbamate formation with primary amines. The results are derived from detailed, ¹H-NMR based, kinetic and equilibrium investigation of the interaction of monoethanolamine, MEA, with carbonate species. All rate and equilibrium constants are reported.