Anticorrosion studies of some hydantoin derivatives for mild steel in 0.5Â M HCl solution: Experimental, quantum chemical, Monte Carlo simulations and QSAR studies

Some hydantoin derivatives namely, 1-methylhydantoin (MHYD), 5,5-dimethyl-hydantoin (DMHYD), hydantoin-5-acetic acid (HYDAC), 1,3-dibromo-5,5-dimethylhydantoin (DBDMHYD), 5-methyl-5-phenylhydantoin (MPHYD), and hydantoin (HYD) were studied as corrosion inhibitors for mild steel in 0.5 M HCl using experimental and theoretical methods. Tafel polarization measurements showed that the hydantoin derivatives are mixed type inhibitors and obeyed the Langmuir adsorption isotherm model. Scanning electron microscopy (SEM) analyses of surface morphology suggested that the hydantoin derivatives protect mild steel surface in 0.5 M HCl. Quantum chemical calculations and molecular dynamic simulations results were in good agreement with the experimental results. Quantitative structure activity relationship studies showed that the inhibitive performances of the studied compounds correlated well with their molecular weights, frontier molecular orbitals energy gap, fraction of electron transferred and binding energy.