Probing molecular interactions and anti-corrosion performance of a group of drugs as green corrosion inhibitors in acidic Environment : Theoretical studies

The mineral acids are widely used in many industries for various metallurgical purposes like, chemical cleaning and descaling. It is a serious problem in industry. Thus results in increase in maintenance costs. Literature survey on green corrosion inhibitor suggest that the essential requirements for the selection of natural products include those containing phytochemicals, or isolated organic compound containing hetero atoms [1]. The purpose of this work is to understand the effect of molecular structure of a group of drugs on corrosion inhibition properties. In this study, the corrosion inhibitory performance of some drugs on mild steel in acidic environment was investigated using Quantum chemical calculation and Molecular Dynamics (MD) simulation. Quantum chemical calculations of Molecular electronic parameters such as Highest Occupied Molecular Orbital (E_HOMO) and Lowest Unoccupied Molecular Orbital (E_LUMO) energies, energy gap (ΔE), chemical potential (μ), electrophilicity (ω) and global hardness (η) and the correlation between the structure of inhibitors was determined by using Density Function Theory (DFT) method at the suitable basis set level. Quantum chemical calculations were explored by DMOL^3 mode in Material Studio 2017. The GGA–PBE basis set in DFT was used to optimize the structure of drugs. Molecular Dynamics (MD) simulations was selected for exploring the adsorption ability of drugs on the target steel metal expressed by Fe (1 1 0) surface. The running of this dynamics simulations was done by the Materials Studio 2017 program. Classical simulations were based on COMPASS as an appropriate force field.