Theoretical study on the corrosion inhibition performance of dibenzo-18-crown-6 and its derivatives

Theoretical studies on the performance of corrosion inhibition of dibenzo-18-crown-6 compounds and its derivatives have been carried out using the B3LYP/631G(d) theory level. The effect of electron donor groups (NH2, OCH3, OH, CH3, CHCH2) and electron withdrawing groups (COOCH3, COOH, CHO, F, NO2) was also studied in the gas and aqueous medium. Electron donor groups increase the value of corrosion inhibition efficiencies; in contrast electron withdrawing groups have the opposite effects. The theoretical calculation indicated that NH2 gave the highest efficiency value, whereas the NO2 group gave the lowest corrosion inhibitor efficiency value. The positive correlation was shown between the corrosion inhibition efficiency and the quantum parameters. The Fukui function showed that the delocalisation of electrons around the benzene ring was the area that most contributes to the bond formed between the metal and the crown ether.