Synthesis and Characterization of a Novel Quaternary Ammonium Salt as a Corrosion Inhibitor for Oil-Well Acidizing Processes.

A quaternary ammonium salt, 1,1'-(1,4-phenylenebis(methylene))bis(4-formylpyridin-1-ium) (PMBF), was synthesized, characterized, and investigated as an inhibitor for C1018 (type steel in oil wells) corrosion in 17.5% HCl solution. The chemical structure of PMBF was confirmed using altered techniques. Potentiodynamic polarization (PDP) was employed to investigate the corrosion inhibition effect of the synthesized compound in a 17.5% HCl solution for C1018. The corrosion protection was increased by improving the dose of the synthesized compound and reached 98.5% at 42.02 × 10 -5 M and 313 K. On the other hand, it was decreased by increasing the temperature and reached 97.9% at the same concentration and 343 K. The parameters of activation and adsorption were calculated and debated. A polarization study revealed that PMBF functioned as a "mixed-kind inhibitor," i.e., affecting both cathodic and anodic processes through their adsorption onto the electrode surface. The adsorption was described by the Langmuir adsorption isotherm. Different techniques were employed as appropriate tools for analyzing the structure of the layer formed on C1018. Density functional theory (DFT) and Monte Carlo (MC) simulations were used to compare the results of the theoretical calculations with the experiments. Finally, an appropriate inhibition mechanism was suggested and discussed.