Electrochemical and Molecular Dynamic Investigation of Some New Pyrimidine Derivatives as Corrosion Inhibitors for Aluminium in Acid Medium

Abstract

A new class of corrosion inhibitors, namely, pyridine-2,6-diamine (PD) , pyrimidin-2-amine (PA), 6-amino-3,4-dihydropyrimidine-2(1H)-thione (ADT) and ethyl (R)-6-(4-chlorophenyl)-2-mercapto-4-methyl-1,6-dihydropyrimidine-5-carboxylate (EMMD) has been used. The influence of these pyridine-pyrimidine on the dissolution of aluminum in molar HCl has been investigated using impedance spectroscopy as well as potentiodynamic polarization and molecular dynamics simulations. Impedance spectroscopy data show that values of constant phase elements, CPE are decreased. Polarization resistance and protection efficiency increase with increasing concentration of pyridine-pyrimidine derivatives as the electric double layer increased. Electronic equivalent circuit of the investigated system is suggested. Potentiodynamic polarization results showed that these derivatives are mixed-type inhibitors with mainly cathodic action. Molecular simulations are used to simulate the adsorption of pyridine-pyrimidine, on the aluminum oxide substrate.