Long-Chain Alkylthia-Benzimidazoles as Corrosion Inhibitors for Carbon Steel in H₂SO₄ Solution

Abstract

A series of long-chain N-arylundecanamides containing benzimidazole thioethers (2a-e) were synthesized and characterized by FT IR, 1 H NMR, and elemental analysis. The corrosion inhibitory properties of these compounds on cold rolled low carbon steel metal coupons were investigated by weight loss measurements in acidic media. Surface characterization studies of the metal coupons used were performed by contact angle measurements using the sessile-drop method. In addition, the 3D image of the metal surface was measured using an optical profilometer. The results obtained from these analyses showed that almost all of the tested compounds between 25-150-ppm concentrations in acidic media are good to excellent corrosion inhibitors with the values of percentage inhibition efficiency (η) = 77-99%.

Recent advances in the use of benzimidazoles as corrosion inhibitors

“…Yildirim et al synthesized a series of 2-substituted benzimidazoles 5a – e in two steps: synthesis of 1 H -Benzo[ d ]imidazol-2-yl)methanethiol 4 by Phillips reaction; and final compounds by refluxing 4 with 11-Bromo- N -arylundecanamide in acetone along with potassium carbonate and a catalytic amount of sodium iodide under nitrogen atmosphere (Fig. 5) [18].

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“…5). The 3D optical profilometer images of the metal to acidic medium without inhibitor show to corrosion damages on the metal surface, while the treatment of the metal with inhibitor prevents the corrosion of the surface [18]. The compounds exhibited the highest inhibition at 0.15 mM inhibitor concentration.…”

Synthesis of Potential Pharmaceutical Heterocycles as Surface Active Agents

“…156-158°C; IR (m/cm -1 ); 3337 (3NH), 2848-2915 (CHaliph), 1714, 1677, 1661 (CO), 1601 (C=C),1536 (C=N), 1259 (C=S). 1 General Procedure for Synthesis of Pyridines (14a, b) and Fused Pyridine Derivatives (15)(16)(17) A solution of chalcone 3 (1 g, 2 mmol) in AcOH (15 mL), acetylacetone (0.2 g, 2 mmol), benzoylacetone (0.32 g, 2 mmol), 1, 3-indandione (0.3 g, 2 mmol), cyclopentanone (0.17 g, 2 mmol), and/or cyclohexanone (0.2 g, 2 mmol) with ammonium acetate (0.4 g), in each case, was heated for 4 h. After cooling, the solution was poured upon ice water (20 mL), filtered and crystallized from EtOH.…”

“…These surface active agents are inexpensive to produce and have various applications in industry, because of applications as emulsifiers, foam stabilization, wetting agents, facilitate solubilization and several biotechnological processes [40][41][42][43][44][45][46]. Addition of number of moles of propylene oxide (10 moles) to the synthesized compounds (4)(5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19)(20) which have active hydrogen atoms in the presence of KOH as a catalyst produced nonionic surface active agents (21)(22)(23)(24)(25)(26)(27)(28)(29)(30)(31)(32)(33)(34)(35)(36)(37), respectively, which may have broader formulation flexibility. The structure of propoxylated products (21)(22)(23)(24)(25)…”

“…Chalcone derivatives are acknowledged to be a tool in the synthesis of pharmacologically interesting heterocyclic systems such as pyrazoles, which are attracting interest due to their bioactivity [13]. Oleochemicals are necessary to a variety of applications such as plastics, surface treatments, paints, lubricants, pharmaceuticals, pesticides, detergents, soaps, textiles, and cosmetic [14][15][16][17][18][19][20]. Extending our past research in this area [21][22][23][24][25][26], we sought to prepare some new isoxazole, pyrazole, puran, pyridine and pyrimidine derivatives and evaluating their surface and biological activities to determine suitability for the applications above.…”