A theoretical study of some hydroxamic acids as corrosion inhibitors for carbon steel

The corrosion inhibition characteristics of two hydroxamic acids, i.e., oxalyl-dihydroxamic acid (C2) and pimeloyl-1,5-di-hydroxamic acid (C7), on carbon steel has been studied using density functional theory (DFT). Quantum chemical parameters such as highest occupied molecular orbital energy (EHOMO), lowest unoccupied molecular orbital energy (ELUMO), and energy gap (ΔE) have been calculated using B3LYP/6-31 + G∗∗ basis set. The relationship between the inhibition efficiency and quantum chemical parameters has been discussed in order to elucidate the inhibition mechanism of these compounds.