Evaluation of Corrosion Inhibition and Adsorption Behavior of 7-Isopropyl-4-methyl-4,5,6,7-tetrahydrobenzoisoxazole against Carbon Steel Corrosion in 1 M HCl. Experimental and Computational Investigations

The corrosion inhibition capabilities of menthone which discovered in 2014 by our team have encouraged us to prepare again a new derivative of menthone called 7-isopropyl-4-methyl-4,5,6,7-tetrahydrobenzoisoxazole (MD). This compound was characterized by FT-IR, 1H NMR and 13C NMR techniques. Then, the evaluation of corrosion inhibition and adsorption behavior of MD onto carbon steel (CS) carried out in 1 M HCl using the weight loss (WL) analysis and electrochemical methods such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS). The inhibition efficiency (IE %) was increased by the increase of both the dose of MD (0.72 to 5.65 mM) and the temperature of the medium (298 to 323K). The thermodynamic kinetic parameters showed that the adsorption of MD on the carbon steel surface follows the Langmuir adsorption isotherm. Furthermore, PDP measurements exhibited that the studied MD inhibitor performs as a mixed-type inhibitor. Finally, the density functional theory (DFT), molecular electrostatic potential (MEPS) and Monte Carlo (MC) studies provide further insights about adsorption mechanism; indicating that the MD inhibitor can effectively limit corrosion onto the carbon steel surface. As a conclusion of this work, we have concluded that the synthesized MD can be used as an efficient inhibitor to stop carbon steel surface corrosion.