Two novel acrylamide derivatives as corrosion inhibitors for API 5l x52 carbon steel in hydrochloric acid solution: synthesis and characterization

Abstract

Two new acrylamide derivatives were prepared namely: “N-(bis(2-hydroxyethyl) carbamothioyl) acrylamide (BHCA) and N-((2-hydroxyethyl) carbamothioyl) acrylamide( HCA) and their chemical structures were analyzed and confirmed using IR and 1H NMR”. These chemicals were investigated as corrosion inhibitors for carbon steel (CS) in 1 M HCl medium using chemical method (weight loss, WL), and electrochemical techniques including potentiodynamic polarization (PDP), and electrochemical impedance spectroscopy (EIS). The results showed that the acrylamide derivatives work well as corrosion inhibitors, with inhibition efficacy (%IE) reaching 94.91–95.28% at 60 ppm for BHCA and HCA, respectively. Their inhibition depend mainly on their concentration and temperature of the solution. According to the PDP files, these derivatives function as mixed-type inhibitors that physically adsorb on the CS surface in accordance with the Langmuir adsorption isotherm, creating a thin coating that shields the CS surface from corrosive fluids. The charge transfer resistance increased and the double layer capacitance (Cdl) decreased as a result of the adsorption of the used derivatives (Rct). Calculated and described were the thermodynamic parameters for activation and adsorption. Quantum chemistry computations and Monte Carlo simulations were examined and discussed for these derivatives under investigation. Validity of the obtained data was demonstrated by the confirmation of these several independent procedures.