DFT study of Lithium, Sodium and Potassium salts of Amino Acids; Global Reactivity Descriptors, Optimized parameters and Hydration Free Energy

Abstract

A promising solvent for removing CO2 from flue gases after combustion is aqueous solutions of amino acid salts of alkali metals. Their computational work would be extremely significant in this area. Amino acid salts of alkali metals are being explored in aqueous solutions for post-combustion CO2 capture from flue gases. In this regard, their computational study would be of the utmost importance. The hydration free energies, total dipole moment, HOMO/LUMO band gap energy, C=O vibration of the –COOH group, bond lengths and bond angles for lithium, sodium and potassium cysteinate and prolinate were computed in the current work using the Gaussian 09 program. Study shows that the hydration free energy for potassium saltsisless than that of corresponding lithium and sodium salts. From result it could be stated that the change of alkali metal(Na/ K)in amino acid saltsare changing the physical structural and vibrational characteristics of amino acid salts. This study would be helpful for their evaluation as a CO2 capturing agent.