Electrochemical and quantum chemical evaluation of new bis(coumarins) derivatives as corrosion inhibitors for carbon steel corrosion in 0.5 M H2SO4

Four new bis(coumarin) compounds were prepared and their structures were confirmed using elemental analysis FTIR, H-1 NMR and mass spectroscopy. The corrosion inhibition tendencies of the prepared compounds were investigated in inhibiting the carbon steel corrosion in 0.5 M H2SO4 using potentiodynamic polarization electrochemical impedance measurements and quantum chemical methods. The results showed that the prepared compounds are efficient and perform their action as mixed type corrosion inhibitors, and their corrosion inhibition tendencies were increased with the rising of their concentration and temperature of measurement. The adsorption of the prepared inhibitors on the carbon steel surface was chemisorption and obeyed Langmuir adsorption isotherm. The results of the quantum chemical calculations and the electrochemical measurements were in good agreement. (C) 2018 Elsevier B.V. All rights reserved.