Semicontinuum Solvation Modeling Improves Predictions of Carbamate Stability in the CO2 + Aqueous Amine Reaction.

ABSTRACT

Quantum chemistry computations with a semicontinuum (cluster + continuum) solvation model have been used to cure long-standing misprediction of aqueous carbamate anion energies in the industrially important CO2 + aqueous amine reaction. Previous errors of over 10 kcal mol(-1) are revealed. Activation energies were also estimated with semicontinuum modeling, and a refined discussion of the competing hypothetical mechanisms for CO2 + monoethanolamine (MEA) is presented. Further results are also presented to demonstrate that the basicity of an amine (aqueous proton affinity) correlates only with CO2 affinity within an amine class secondary amines have an extra CO2 affinity that primary amines do not have.