Tipping effect of tetra-alkylammonium on the potency of N-(6-(1H-benzo[d]imidazol-1-yl)hexyl)-N, N-dimethyldodecan-1-aminium bromide (BIDAB) as corrosion inhibitor of austenitic 304L stainless steel in oil and gas acidization: Experimental and DFT approach

• Published in: Journal of molecular liquids 2022-08, Vol.360, p.119431, Article 119431
• Main Authors: Odewunmi, Nurudeen A., A.J. Mazumder, Mohammad, Ali, Shaikh A.
• Format: Article
• Language: English
• Subjects: Acid corrosion; Austenitic stainless steel; Benzimidazole; Density functional theory; Electrochemical corrosion; Quaternary ammonium; X-ray photoelectron spectroscopy
• ISSN: 0167-7322; 1873-3166
• DOI: 10.1016/j.molliq.2022.119431

[Display omitted] •BIDAB consists of benzimidazole and tertiary ammonium moieties separated by a C-12 alkyl chain has been synthesized.•The corrosion inhibition efficiency of BIDAB on 304L SS in 15% HCl was demonstrated experimentally and by DFT studies.•The corrosion inhibition of 404.37 μM BIDAB on a susceptible 304L SS in 15% HCl was found to be greater than 98% at 298.15 K.•The electrochemical studies show that BIDAB exhibits a mixed-type corrosion inhibition mechanism.•Adsorption of BIDAB obeyed Langmuir adsorption and exhibited a typical physisorption adsorption mechanism. A new class of quaternary ammonium bromide; N-(6-(1H-benzo[d]imidazol-1-yl)hexyl)-N, N-dimethyldodecan-1-aminium bromide (BIDAB) was successfully synthesized and characterized with FTIR, elemental analyzer, 1H, and 13C NMR spectroscopy instruments revealing embedded benzimidazole and other functional groups in the compound. The efficacy of 404.37 μM BIDAB as an effective corrosion inhibitor of 304L SS in 15% HCl exhibited over 97% inhibition efficiency at 298.15 K by electrochemical frequency modulation (EFM), electrochemical impedance spectroscopy (EIS), polarizations, and weight loss measurements. The adsorption of BIDAB on the 304L stainless steel surface was studied by FESEM-EDX and X-ray photoelectron spectroscopy (XPS). The adsorption of BIDAB was found to obey the Langmuir isotherm model and demonstrate a typical physisorption behavior at elevated temperatures. The withdrawer of electrons from the benzimidazole ring owing to the tipping effect phenomenon of the tetra-alkyl ammonium functional group was suspected to be responsible for the typical physisorption behavior of BIDAB inhibitor as disclosed by the density functional theory (DFT) calculation’s chemical descriptors and the frontier orbitals (HOMO-LUMO) structures of the protonated BIDAB.