Computational Comparison of the Reactions of Substituted Amines with CO₂

Abstract

Substituted amines are a popular choice as molecules to selectively react with and separate CO2 from gas mixtures. Such separations are of particular interest, for example, for CO2 separations for carbon capture and sequestration. It is desirable to tune amine–CO2 reaction energies to suit a particular separation. Herein, we use DFT‐B3LYP simulations to characterize the products and energetics of reactions of CO2 with a range of substituted amines, considering both 1:1 and 2:1 amine/CO2 reaction stoichiometries. The results show that by adjusting both the nature and the placement of functional groups, it is possible to tune reaction energies over a substantial range. Decomposition of the 2:1 reaction into separate carbamate and ammonium formation steps shows that the Brønsted basicity and Lewis basicity towards CO2 are largely uncorrelated and provide an independent means of tuning the overall reaction energies.

Optimization of selection of chain amine scrubbers for CO2 capture

“…Schneider et al [16] showed using DFT-B3LYP calculations that the reaction energies of CO 2 with amine are a function of both substituents and stoichiometry; in good agreement with the experimental findings [17], they found that a negatively charged amine reacts with CO 2 in a 1:1 ratio.…”

A rate based model of a packed column for CO2 absorption using aqueous monoethanolamine solution

“…According to this, different rate based models may be derived depending on the assumptions and approximations used. Currently, research effort is also being devoted to the overall reaction mechanisms involved in the CO 2 absorption into amine and its effects on the absorption efficiency (Sexton and Rochelle, 2011;Bedell, 2011;Qin et al, 2010;Mindrup and Schneider, 2010;Lepaumier et al, 2009a,b;Lepaumier et al, 2010). In addition, detailed mathematical models based on both film and penetration theories are being developed (Simon et al, 2011;Faramarzi et al, 2010;Edali et al, 2009;Zhang et al, 2009;Lawal et al, 2009;van Loo et al, 2007).…”

Room temperature flexible isocyanate-free polyurethane foams

“…The phenomenon of carbonation of amines with CO 2 of air is well known [68,69]. Therefore the diamine has been previously distilled under vacuum at 120°C and stored under inert gas (Argon).…”