Reversible reaction of Carbon Dioxide and Amines

Gaseous carbon dioxide (CO₂) can be captured using aqueous organic amines such as ethanolamine prior to storage, reuse, or sequestration. The reversible amine-based absorption−desorption capture process is regarded as the most mature and economical technology due to its extensive use in related industrial applications.

Nucleophilic attack of the primary amine on carbon dioxide produces a zwitterion intermediate containing an ammonium cation and a carboxylate anion. The ammonium cation can then lose a proton to a base to form the carbamate anion.

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Yang, X.; Rees, R. J.; Conway, W.; Puxty, G.; Yang, Q.; Winkler, D. A. Computational Modeling and Simulation of CO2 Capture by Aqueous Amines. Chem. Rev. 2017, 117 (14), 9524–9593.