Electrochemical and Theoretical Studies of Adsorption and Corrosion Inhibition of N,N′-Bis(2-hydroxyethoxyacetophenone)-2,2-dimethyl-1,2-propanediimine on Low Carbon Steel (API 5L Grade B) in Acidic Solution

Abstract

Schiff base N,N′-bis(2-hydroxyethoxyacetophenone)-2,2-dimethyl-1,2-propanediimine (H2(hppnptn)) as corrosion inhibitor for API 5L grade B low carbon steel in hydrochloric acid solutions has been studied using electrochemical techniques and surface techniques. Results showed that the inhibition occurs through adsorption of the inhibitor molecules on the metal surface. Thermodynamic parameters for adsorption and activation processes were determined. Polarization data indicated that this compound acts as mixed-type inhibitors, and the adsorption isotherm basically obeys the Langmuir adsorption isotherm. The calculations of reactivity indices of H2(hppnptn) such as the localization of frontier molecular orbitals, E HOMO , E LUMO , energy gap (Δ E ), dipole moment (D), hardness (η), softness (σ), the fractions of electrons transferred (ΔN), electrophilicity index (ω), total energy change (Δ E T ), and natural bond orbital (NBO) charge distributions together with local reactivity by means of Fukui indices were used to explain the electron transfer mechanism between the H2(hppnptn) molecules and the steel surface.

Impedance Spectroscopy Studies on Corrosion Inhibition Behavior of Synthesized N,N’-bis(2,4-dihydroxyhydroxybenzaldehyde)-1,3-Propandiimine for API-5L-X65 Steel in HCl Solution

“…The addition of DHBP causes a remarkable decrease in the corrosion rate. These results are indicative of the adsorption of inhibitor molecules on the active sites of steel surface [16]. The inhibition of steel corrosion increases with increasing inhibitor concentrations.…”

“…Generally, the values of ∆G ads around or less than -30 kJ mol -1 are associated with the electrostatic interaction between charged molecules and the charged metal surface (physisorption); while those around or higher than -40 kJ mol -1 mean charge sharing or transfer from the inhibitor molecules to the metal surface to form a coordinate type of metal bond (chemisorption). The values of K ads and ∆G ads are 1.1×10 -4 l mol -1 and -33.03 kJ mol , which means that the absorption of DHBP on the steel surface belongs to the physisorption and the adsorptive film has an electrostatic character [11,16].…”

“…Adsorption isotherms provide information about the interaction of the adsorbed molecules with the metal surface [16]. The efficiency of schiff base molecules as a successful corrosion inhibitor mainly depends on their adsorption ability on the metal surface.…”

The Effect of Immersion Time and Immersion Temperature on the Corrosion Behavior of Zinc Phosphate Conversion Coatings on Carbon Steel

“…To obtain a satisfactory impedance simulation of phosphate coated steel, it is necessary to replace the capacitor (C) with a constant phase element (CPE) Q in the equivalent circuit. The most widely accepted explanation for the presence of CPE behavior and depressed semicircles on solid electrodes is microscopic roughness, causing an inhomogeneous distribution in the solution resistance as well as in the double-layer capacitance 30,31 . To corroborate the equivalent circuit, the experimental data were fitted to equivalent circuit and the circuit elements were obtained.…”

Investigation of Thermodynamic Parameters for Steel Corrosion in Acidic Solution in the Presence of N,N′-Bis(phloroacetophenone)-1,2 propanediamine

“…Even with advanced corrosion-resistant materials available, carbon steel has been widely employed as the construction material for pipe works in the oil and gas production such as downhole tubular flow lines and transmission pipelines. Steel pipelines play an important role in transporting gases and liquids throughout the world [2]. Moreover, appropriate corrosion control can help avoid many potential disasters that can cause serious issues including loss of life, negative social impacts, and water resource and environmental pollution [3,4].…”