Theoretical approach for the performance of 4-mercapto-1-alkylpyridin-1-ium bromide as corrosion inhibitors using DFT

Abstract

Density function theory (DFT) study on adsorptivity and corrosion inhibition performance of 4-mercapto-1-alkylpyridin-1-ium bromide (where R = C8, C10 and C12) on carbon steel in 1 M HCl solution was presented. Quantum chemical descriptors were investigated to explain the performance of these molecules as corrosion inhibitors. These descriptors were EHOMO; energy of the highest occupied molecular orbital, ELUMO; energy of the lowest unoccupied molecular orbital, ΔE; the energy gap, η; Global hardness, S; global softness, I: ionization potential, A: electron affinity, X: absolute electronegativity, ΔN; the fraction of electron transferred, ω; global electrophilicity index, ΔEBack-donation; the back donation, f+, f−; Fukui indices for local nucleophilic and electrophilic attacks and s+, s− local softness. The result of descriptors calculation pronounces that the theoretical approach complies with the reported experimental data.