Synthesis, characterization and corrosion inhibition studies of polyunsaturated fatty acid derivatives on the acidic corrosion of mild steel: Experimental and computational studies

Abstract

In an effort to make an efficient and benign CI for the purpose of acidizing, a novel range of new derivatives of polyunsaturated fatty acids (PUFA) were prepared from a group of amines and Z-9,12-octadecadienoic acid with Excellent yields. Elemental analysis, FTIR, 13C NMR and 1H NMR was employed to realize a description for the newly manufactured compound. The inhibitive action of synthesized amides was examined by means of potentiodynamic polarization techniques and weight loss measurements in 1.00 M HCl. Derivatives of Z-9,12-octadecadienoic acid amides (DA) were found to obey the Langmuir adsorption model. The hydrophobic nature of mild steel (MS) was revealed by measurement of the contact angle in the presence of CI. The experimental findings were found to be supported by quantum chemical calculations. Inhibition efficiencies were computed for various DA concentrations for inhibition against the wear of MS in 100.00 ml of 1.00 M HCl, with exposure for four days at temperatures ranging from 298 to 333 K. For a DA concentration of 100 ppm, every inhibitor molecule showed outstanding percentage inhibition efficiencies in 1.00 M HCl. Compounds 2, 3, 4, 5, 6, 7, 8 and 9 offered a robust percentage inhibition efficiency of 92.90, 86.6, 49.8, 82.7, 85.9, 96.70, 94.30 and 91.30, correspondingly, at 100 ppm. The interaction of the p-electrons in compounds with low-energy, empty Fe d-orbitals helped the inhibitive molecules (IMs) to experience adsorption and inhibit the process of anodic dissolution. When Tafel plots were employed for the compounds used in the electrochemical method, similar findings were obtained for the percentage inhibition efficiencies. Compound adsorption on the MS surface was discovered to obey Arrhenius and Transition state plots in 1.00 M HCl.