Synthesis and inhibitive characteristic of two benzothiazole derivatives towards the corrosion of carbon steel in hydrochloric acid solutions

A new class of benzothiazole derivatives has been synthesized, including BTMA-1 (2-cyano-3-(4-(dimethylamino) phenyl)-N-(6-methylbenzo[ d ]thiazol-2-yl) acrylamide) and BTMA-2, 2-cyano-N-(6-methylbenzo[ d ]thiazol-2-yl)-3-(4-nitrophenyl) acrylamide. Their structures were determined using IR and (N., 2024 [ 1) ]HNMR spectroscopy. Weight loss (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and theoretical analyses were used to assess the effectiveness of synthesized compounds in protecting the carbon steel corrosion in 2 M HCl. “According to the obtained findings, BTMA-1 and BTMA-2 compounds were adsorbed on the carbon steel surfaces and inhibit corrosion effectively”. The inhibitory efficacy rises with increasing the concentration of BTMA compounds, reaching a high of 87.6 % for BTMA-1 and 93.1 % for BTMA-2. The study revealed that the effectiveness of tested compounds as inhibitors increased with increasing the concentration but decreased with raising temperature. These compounds were found to function as mixed-type inhibitors. “Surface analyses conducted using different techniques confirmed the formation of a protective layer on the carbon steel surface”. This protective layer occurs due to the adsorption behavior of benzothiazole derivatives following Langmuir's adsorption isotherm with adsorption energies of −40.17 kJ mol −1 for BTMA-1, −39.93 kJ mol −1 for BTMA-2, suggesting chemisorption. Further understanding of the inhibitory mechanism was made possible by DFT-based quantum chemical indices. The inhibitor's conformational adsorption modification on the iron surface was also predicted using molecular dynamics simulations. Furthermore, kinetic and thermodynamic characteristics were computed. Experimental results are mostly consistent with theoretical ones.