Atomic-scale investigation onto the inhibition process of three 1,5-benzodiazepin-2-one derivatives against iron corrosion in acidic environment

Abstract

In the aim to understand the inhibition action of three 1,5-benzodiazepin-2-one derivatives (i.e. DMBD: 4,7-dimethyl-1,5-benzodiazepin-2-one, PBD: 3-phenyl-1,5-benzodiazepin-2-one, MPBD: 4-methyl-7-phenyl-1,5-benzodiazepin-2-one) against the dissolution of iron in acidic medium, both DFT-based calculations and Monte Carlo-SAA simulations were carried out. As a result, the protonation process was unfavorably affected the reactivity of investigated inhibitors. Further, the solvation free energy (∆GSolv) can be used as a parameter to inspect the inhibition performance of organic inhibitors. According to Monte Carlo-SAA simulations, the investigated inhibitors exhibited a great tendency to replace pre-adsorbed corrosive entities onto the iron surface and then forming a protective film via a parallel adsorption orientation. Finally, a predicting study pointed out that the MPBD compound is expected to act as a moderate inhibitor for aluminum and copper metals, while lower inhibition efficiency is anticipated in the case of tin in acidic environments.