Theoretical studies on the corrosion inhibition performance of three amine derivatives on carbon steel: Molecular dynamics simulation and density functional theory approaches

Inhibition efficiencies of three amine derivatives (diethylenetriamine I, triethylenetetramine II, and pentaethylenehexamine III) on corrosion of carbon steel has been studied using the density functional theory method and molecular dynamic simulation in aqueous phase. Quantum chemical parameters such as E-HOMO (highest occupied molecular orbital energy), E-LUMO (lowest unoccupied molecular orbital energy), hardness (eta), polarizability (alpha), dipole moment (mu), total negative charges on atoms (TNC) and molecular volume (MV) have been calculated at the B3LYP level of theory with 6-311++G** basis set. Moreover, adsorption behavior of the inhibitor molecules on Fe (110) surface has been analyzed using molecular dynamics simulation. The formation of the bonding and nonbonding interactions in systems of Fe-inhibitor molecules on Fe (110) surface followed the order III>II>I, which was in a good agreement with the experimentally determined inhibition efficiencies. The formation of bonding and nonbonding interactions in systems of Fe-inhibitor was analyzed by the radial distribution functions (RDFs). In agreement with the experimental data, theoretical results showed that the order of inhibition efficiency is III>II>I. (C) 2016 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.