Corrosion inhibition of N80 steel in simulated acidizing environment by N-(2-(2-pentadecyl-4,5-dihydro-1H-imidazol-1-YL) ethyl) palmitamide

Imidazoline As a Volatile Corrosion Inhibitor for Mitigation of Top- and Bottom-of-the-Line CO2 Corrosion in Carbon Steel Pipelines

A fatty acid imidazoline-based inhibitor was synthesized via a facile solvent-free synthesis method between tall oil fatty acid (TOFA) and diethylenetriamine (DETA) under atmospheric conditions with a short reaction time. The as-synthesized imidazoline (S-Imd) acted as an effective inhibitor for reducing or preventing corrosion of carbon steel pipelines at both bottom of the line (BOL) and top of the line (TOL) positions under simulated conditions of a gas pipeline in a CO2-saturated environment. The inhibition efficacy was examined by both weight loss and electrochemical measurements, such as the electrochemical impedance spectrum (EIS), potentiodynamic polarization (PDP), and linear polarization resistance (LPR). The results revealed that the S-Imd, 2-(8-heptadecenyl)-2-imidazoline-1-ethanamin, at 300 ppm exhibited a superior inhibition efficiency of up to 91.6 and 89.9% for BOL and TOL corrosion tests, respectively. The surface morphology of the carbon steel test specimens was also examined using scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDAX), and contact angle analysis. It was found that the as-synthesized S-Imd acted as a mixed-type inhibitor that exhibited a decreased surface roughness and oxide layer on carbon steel surfaces. However, the water contact angle was found to increase, implying enhanced hydrophobicity of the surface. Adsorption of the imidazoline molecules on carbon steel surfaces followed the Langmuir adsorption isotherm. The present work provides very promising results in the synthesis and utilization of the studied imidazoline as a volatile corrosion inhibitor (VCI), especially for carbon steel pipelines in petroleum industries.

Temperature Effect on the Corrosion Inhibition of Carbon Steel by Polymeric Ionic Liquids in Acid Medium

In the present research work, the temperature effect on the corrosion inhibition process of API 5L X60 steel in 1 M H2SO4 by employing three vinylimidazolium poly(ionic liquid)s (PILs) was studied by means of electrochemical techniques, surface analysis and computational simulation. The results revealed that the maximal inhibition efficiency (75%) was achieved by Poly[VIMC4][Im] at 308 K and 175 ppm. The PILs showed Ecorr displacements with respect to the blank from −14 mV to −31 mV, which revealed the behavior of mixed-type corrosion inhibitors (CIs). The steel micrographs, in the presence and absence of PILs, showed less surface damage in the presence of PILs, thus confirming their inhibiting effect. The computational studies of the molecular orbitals and molecular electrostatic potential of the monomers suggested that the formation of a protecting film could be mainly due to the nitrogen and oxygen heteroatoms present in each structure.

Inhibition Mechanism of Some Vinylalkylimidazolium-Based Polymeric Ionic Liquids against Acid Corrosion of API 5L X60 Steel: Electrochemical and Surface Studies

A corrosion inhibition mechanism of API 5L X60 steel exposed to 1.0 M H₂SO₄ was proposed from the evaluation of three vinylalkylimidazolium poly(ionic liquids) (PILs), employing electrochemical and surface analysis techniques. The synthesized PILs were classified as mixed-type inhibitors whose surface adsorption was promoted mainly by bromide and imidazolate ions, which along with vinylimidazolium cations exerted a resistive effect driven by a charge transfer process by means of a protective PIL film with maximal efficiency of 85% at 175 ppm; the steel surface displayed less surface damage due to the formation of metal-PIL complex compounds.

Efficient Synthesis of 6,7-Dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile Compounds and Their Applicability As Inhibitor Films for Steel Alloy Corrosion: Collective Computational and Practical Approaches

An effective method for designing new heterocyclic compounds of 6,7-dihydro-5H-cyclopenta[b]pyridine-3-carbonitrile derivatives (CAPDs) was presented through cyclocondensation reaction between 2,5-diarylidenecyclopentanone derivatives and propanedinitrile, and the cyclocondensation reaction succeeded using a sodium alkoxide solution (sodium ethoxide or sodium methoxide) as the reagent and the catalyst. The synthesized CAPD derivatives were employed as novel inhibitors for carbon steel (CS) corrosion in a molar H2SO4 medium. The corrosion protection proficiency was investigated by electrochemical measurements (open circuit potential vs time (E OCP vs t), potentiodynamic polarization plots (PDP), and electrochemical impedance spectroscopy (EIS)) and surface morphology (scanning electron microscopy (SEM)) examinations. The results show that the CAPD derivatives exhibit mixed type inhibitors and a superior inhibition efficiency of 97.7% in the presence of 1.0 mM CAPD-1. The adsorption of CAPD derivatives on the CS interface follows the Langmuir isotherm model, including physisorption and chemisorption. Scanning electron microscopy (SEM) exploration confirmed the adsorption of the CAPD derivatives on the CS substrate. Monte Carlo (MC) simulations and DFT calculations revealed that the efficacy of the CAPD molecules correlates well with their structures, and this protection was attributed to their adsorption on the CS surface.

Date palm leaves extract as a green and sustainable corrosion inhibitor for low carbon steel in 15 wt.% HCl solution: the role of extraction solvent on inhibition effect

Date palm leaves (DPL) was extracted using acetone (ACE), ethanol (ETH), aqueous (AE), butanol (BUT), methanol (METH), isopropanol (ISO), and ethyl acetate (EHY ACT). The extracts were characterized using Fourier-transform infrared spectroscopy (FTIR) and ultraviolet-visible (UV-vis) spectroscopy. The various solvent DPL extracts were screened for anticorrosion property against low carbon steel in 15 wt.% HCl solution at 25 °C. ACE, AE, and ETH DPL extracts are found to promote the corrosion of the low carbon steel while BUT, ISO, METH, and EHY ACT DPL extracts exhibit anticorrosion property. However, BUT DPL extract shows the best anticorrosion property with 400 ppm protecting the low carbon steel by 82%. Based on the results from the screening experiments, BUT extract was selected for a comprehensive corrosion inhibition study. Inhibition effectiveness of BUT DPL extract is found to increase with increasing concentration with 1000 ppm affording 97% protection at 25 °C. The inhibition performance increases up to 40 °C but slightly decreases as the temperature was raised to 50 °C and 60 °C. However, BUT DPL extract could afford 86% protection at 60 °C. Scanning electron microscope and atomic force spectroscopy results confirm that BUT DPL extract is indeed an effective inhibitor for X60 carbon steel in 15 wt.% HCl solution.

Adsorption and inhibition behavior of imidazolium tetrafluoroborate derivatives as green corrosion inhibitors for carbon steel

The adsorption and inhibition mechanism of chain length increase and group substitution of imidazole tetrafluoroborate derivatives for the corrosion inhibition of carbon steel in HCl solution was revealed in detail via the density functional theory, molecular dynamics (MD) simulation, and quantitative structure-activity relationship (QSAR) methods. The main reactive site of an ionic liquid is located on its imidazolium ring. With alkyl chain lengthening or the introduction of methyl groups onto the imidazolium ring, its molecular reactivity and electron-donating ability increase the interaction between the ionic liquid and the Fe (110) surface. Therefore, the imidazolium rings of four IL inhibitors are more likely to lie on the Fe (110) surface in parallel through chemical adsorption. The interactions between N atoms in ionic liquids and the Fe (110) surface are stronger than those between the C atoms on the imidazolium rings of the four ionic liquid, and coordination bonds can be formed between N atoms and the Fe (110) surface. Therefore, ionic liquids can hinder the interaction between corrosion particles and the Fe (110) surface, hinder the diffusion of corrosion particles, and effectively reduce the number density of corrosion particles on the Fe (110) surface. A methyl substituent on the C2 atom of the imidazolium ring can enhance the electron-donating ability and adsorption tendency much more than an increase in the alkyl chain on the N3 atom. The four inhibitors are ordered in terms of corrosion inhibition efficiency as [C₁₂DMIM]BF₄ > [C₁₀DMIM]BF₄ > [C₁₂MIM]BF₄ > [C₁₀MIM]BF₄, which agrees well with the experimental results. A good correlation between experimental inhibition efficiency, concentration and microscopic structures parameters of ILs such as energy gap ΔE, polarizability P, electronegativity χ, hardness η, softness σ, number of electrons transferred ΔN, and electrophilicity ω was achieved.

Comparative Studies of the Corrosion Inhibition Efficacy of a Dicationic Monomer and Its Polymer against API X60 Steel Corrosion in Simulated Acidizing Fluid under Static and Hydrodynamic Conditions

N ¹,N ¹-diallyl-N ⁶,N ⁶,N ⁶-tripropylhexane-1,6-diaminium chloride (NDTHDC) and its polymer poly(N ¹,N ¹-diallyl-N ⁶,N ⁶,N ⁶-tripropylhexane-1,6-diaminium chloride) (poly-NDTHDC) were synthesized and tested against API X60 carbon steel corrosion in 15 wt % HCl solution. Weight loss, electrochemical, and surface analysis techniques were used. Results show that poly-NDTHDC is better than NDTHDC. Moreover, 1000 mg/L NDTHDC protected the studied surface by 79.1% at 25 °C, while 100 mg/L poly-NDTHDC afforded 86.1% protection. Inhibition efficiency increases with temperature (up to 60 °C) but depreciates thereafter. NDTHDC and poly-NDTHDC perform better under the hydrodynamic condition than the static condition. TGA and FTIR results reveal that poly-NDTHDC is chemically and thermally stable.

Impact of Degree of Hydrophilicity of Pyridinium Bromide Derivatives on HCl Pickling of X-60 Mild Steel: Experimental and Theoretical Evaluations

Dodecyl pyridinium bromide (DDPB), tetradecyl pyridinium bromide (TDPB) and dodecyl 1,1′-bispyridinium dibromide (DDBPB) were successfully synthesized, characterized and evaluated for HCl pickling of X-60 low carbon steel. Order of corrosion inhibitions efficiencies, as revealed by both electrochemical and gravimetric studies, is TDPB > DDPB > DDBPB. The degree of hydrophilicity of inhibitors as predicted by a partition coefficient (Log P) and supported by a contact angle measurement was found to be responsible for their order of corrosion inhibition efficiencies. Adsorption of DDPB, TDPB, and DDBPB through the pyridinium nitrogen on mild steel surface was confirmed by ATR-FTIR and SEM-EDX analyses. The pyridinium nitrogen was found not to be the only factor responsible for their efficiency, but hydrophobes and the orientation of the hydrophilic ring were responsible, which incline to the deviation of experimental results and the order of Monte Carlo simulation adsorption energies. DDPB, TDPB, and DDBPB obey the Langmuir isotherm model despite major contributions of the film formed on the surface of X-60 mild steel on their overall inhibition corrosion resistance.

Epoxy pre-polymers as new and effective materials for corrosion inhibition of carbon steel in acidic medium: Computational and experimental studies

Present study is designed for the synthesis, characterization and corrosion inhibition behavior of two diamine aromatic epoxy pre-polymers (DAEPs) namely, N1,N1,N2,N2-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP1) and 4-methyl-N1,N1,N2,N2-tetrakis (oxiran-2-ylmethyl) benzene-1,2-diamine (DAEP2) for carbon steel corrosion in acidic medium. Synthesized DAEPs were characterized using spectral (Nuclear magnetic resonance (1H NMR) and Fourier transform infrared-attenuated total reflection (FTIR-ATR)) techniques. Viscosity studies carried out at four different temperatures (20-80 °C) increase in temperature causes significant reduction in their viscosities. The anticorrosive properties of DAEPs differing in the nature of substituents, for carbon steel corrosion in 1 M HCl solution was evaluated using several experimental and computational techniques. Both experimental and computational studies showed that inhibitor (DAEP2) that contains electron releasing methyl (-CH3) showed higher protectiveness as compared to the inhibitor (DAEP1) without substituent (-H). Electrochemical results demonstrate that DAEPs act as reasonably good inhibitors for carbon steel in 1 M HCl medium and their effectiveness followed the sequence: DAEP2 (92.9%) > DAEP1 (91.7%). The PDP results show that the diamine aromatic epoxy pre-polymers molecules (DAEPs) act as mixed type inhibitors. Electrochemical study was also supported using scanning electron microscopy (SEM) method were significant improvement in the surface morphology of inhibited (by DAEPs) metallic specimens was obtained. Results derived from computational density functional theory (DFT) and molecular dynamics (MD) simulationsand studies were consistent with the experimental results derived from SEM, EIS and PDP electrochemical studies. Adsorption of the DAEPs obeyed the Langmuir adsorption isotherm model.