Synthesis and inhibitive behavior of new thiazolyl-pyrazole derivative at low carbon steel/HCl interface: Electrochemical, morphology and theoretical investigations

The electrochemical techniques such as potentiodynamic polarization (PDP), electrochemical frequency modulation (EFM), and electrochemical impedance spectroscopy (EIS) were studied for corrosion inhibi-tion of low carbon steel (L-cs) in HCl (0.5 Molar) utilizing new ethyl 4-(5-acetyl-4-amino-3-(thiazol-2-ylcarbamoyl)-1H-pyrazol-1-yl)benzoate (EATPB) inhibitor. The surface characterization via scanning electron microscope (SEM) and atomic force microscope (AFM) were used to support the adsorption properties of (EATPB). Experiments demonstrated that when the concentration of (EATPB) increases, the inhibition efficiency increases, peaking at (89 %) at 30 degrees C. The (PDP) data suggested that (EATPB) is (a mixed type) inhibitor and the impedance technique revealed that the resistance of charge transfer (Rct) increased as the concentration of (EATPB) increased. The adsorption mode of (EATPB) on L-cs sur-face is a mixture between physical and chemical adsorption, DGadsis (-39.2 kJ mol-1) at 30 degrees C, and belongs to the Langmuir isotherm. Surface analysis of L-cs by SEM and AFM was established the creation of pro-tective organic film covering the L-cs surface. The active centers of the (EATPB) responsible for the adsorption, as well as their probable mechanism of interaction with the L-cs surface, were determined using theoretical analyses at the density functional theory (DFT) level. In this study, a new (EATPB) was synthesized laboratory, and was proved using spectroscopic tools for example FTIR, 1H-NMR and 13C-NMR.(c) 2022 Published by Elsevier B.V.