An experimental and theoretical investigation of adsorption characteristics of a Schiff base compound as corrosion inhibitor at mild steel/hydrochloric acid interface

Experimental and computational chemical studies on the corrosion inhibitive properties of carbonitrile compounds for carbon steel in aqueous solutions

The present work aims to study 6-amino-4-aryl-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile derivatives namely: 6-Amino-2-oxo-1,4-diphenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-H), 6-Amino-2-oxo-1-phenyl-4-(p-tolyl)-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-Me) and 6-Amino-4-(4-hydroxyphenyl)-2-oxo-1-phenyl-1,2-dihydropyridine-3,5-dicarbonitrile (PdC-OH) as corrosion inhibitors to provide protection for carbon steel in a molar hydrochloric acid medium. Chemical measurements such as (weight loss) and electrochemical techniques such as (Potentiodynamic polarization, electrochemical impedance spectroscopy, and Electron frequency modulation) were applied to characterize the inhibitory properties of the synthesized derivatives. The adsorption of these derivatives on the carbon steel surface was confirmed by Attenuated Total Refraction Infrared (ATR-IR), Atomic Force Microscope (AFM), and X-ray Photoelectron Spectroscopy (XPS). Our findings revealed that the tested derivatives have corrosion inhibition power, which increased significantly from 75.7 to 91.67% on the addition of KI (PdC-OH:KI = 1:1) to inhibited test solution with PdC-OH derivative at 25 °C. The adsorption process on the metal surface follows the Langmuir adsorption model. XPS analysis showed that the inhibitor layer consists of an iron oxide/hydroxide mixture in which the inhibitor molecules are incorporated. Computational chemical theories such as DFT calculations and Mont Carlo simulation have been performed to correlate the molecular properties of the investigated inhibitors with experimental efficiency. The theoretical speculation by Dmol3 corroborates with the results from the experimental findings.

Synthesis, Cyclic Voltammetric, Electrochemical, and Gravimetric Corrosion Inhibition Investigations of Schiff Base Derived from 5,5-Dimethyl-1,3-cyclohexanedione and 2-Aminophenol on Mild Steel in 1 M HCl and 0.5 M H2SO4

Schiff base 2,2’-(5,5-dimethylcyclohexane-1,3-diylidene)bis(azan-1-yl-1-ylidene) diphenol (DmChDp) was synthesized and characterized using spectroscopic methods (IR, UV, NMR, and Mass) and cyclic voltammetric (CV) studies. The corrosion inhibition potency of (DmChDp) on mild steel (MS) in 1M HCl and 0.5M H2SO4 was investigated. The corrosion monitoring techniques employed for this purpose are gravimetric and electrochemical methods (EIS and potentiodynamic polarization studies). The study reveals that the Schiff base, DmChDp, acts as excellent corrosion inhibitor on mild steel in 1M HCl. DmChDp obeys Langmuir adsorption isotherm both in 1M HCl and 0.5M H2SO4 on MS. Polarization studies show that DmChDp behaves as a mixed type inhibitor in both media. Scanning electron microscopic analysis established the protective nature of DmChDp on mild steel surface. The impact of temperature on the corrosion of MS was also evaluated using gravimetric method.

Study of the structure–bioactivity relationship of three new pyridine Schiff bases: synthesis, spectral characterization, DFT calculations and biological assays

Schiff bases exhibit a broad range of applications, including their use as catalysts, stabilizers, dyes, and intermediates in organic synthesis; and biological activities, such as antifungal properties.

N-Methyl-N,N,N-trioctylammonium chloride as a novel and green corrosion inhibitor for mild steel in an acid chloride medium: electrochemical, DFT and MD studies

In the present work, N-methyl-N,N,N-trioctylammonium chloride (Aliquat 336) has been evaluated as a green and novel corrosion inhibitor for mild steel in a 1 M HCl solution.

Experimental and Theoretical Study on Corrosion Inhibition of Mild steel in 20 % Formic Acid Solution Using Schiff Base-Based Cationic Gemini Surfactant

The paper investigates the adsorption and corrosion inhibition behavior of Schiff base-based cationic gemini surfactant bis-[p-(N,N,N-dodecyldimethylammonium bromide) benzylidene]thiourea, designated as (12-S-12) on mild steel in 20 % formic acid solution in the temperature range of 30 – 60 °C. The synthesized inhibitor was characterized using nuclear magnetic resonance spectroscopy (NMR). The adsorption and corrosion inhibition mechanism of the inhibitor was elaborated using weight loss measurements, solvent analysis of iron ions, potentiodynamic polarization measurements, electrochemical impedance measurements, measurement of thermodynamic/kinetic parameters and quantum chemical calculations. The surface morphology of the corroded mild steel specimen was evaluated using scanning electron microscopy (SEM) and energy dispersive X-ray analysis (EDAX). The inhibition efficiency of the compound was found to vary with the inhibitor concentration and temperature. The inhibitor was found to be a mixed type inhibitor. Adsorption process on mild steel surface followed Langmuir's model adsorption isotherm.

Electrochemical and theoretical study of the inhibition effect of two synthesized thiosemicarbazide derivatives on carbon steel corrosion in hydrochloric acid solution

The inhibition effect of two synthesized thiosemicarbazide derivatives on carbon steel corrosion was studied experimentally (FFT-Voltammetry) and theoretically.