Experimental and theoretical (DFT&MC) studies for newly synthesized cationic amphiphilic substance based on a naphthol moiety as corrosion inhibitor for carbon steel during the pickling process

Abstract New cationic amphiphilic substance (DMNAPDAB) (namely: N,N-dimethyl-N-(3-(2-(naphthalene-1-yloxy)acetoxy)propyl)dodecan-1-aminium bromide) was evaluated as corrosion inhibitor. Carbon steel (CS) corrosion behavior in 5% HCl was investigated via electrochemical impedance spectroscopy (EIS), potentiodynamic polarization (PP), weight loss (WL), SEM & EDX techniques. Inhibition performance improves with rising DMNAPDAB dosage and falls slightly when the temperature increases. DMNAPDAB adsorption on to CS surface is consistent with Langmuir isotherm. The adsorption and kinetic thermodynamics values showed the inhibition of DMNAPDAB at CS surface arises by adsorption. A mixed-type inhibitor mechanism of DMNAPDAB was proposed via PP technique. We found that DMNAPDAB is an excellent inhibitor and addition in this field. Adsorption affinity of DMNAPDAB on CS surface was verified via Monte Carlo (MC) simulation. Simulations in gas and solvent phases have been done after many cycles (150,000 cycles) till obtain the stability. The chemical, electrochemical and theoretical results supported by SEM and EDX results. SEM and EDX results recommended the DMNAPDAB forms the protective film on CS surface. We compare the DMNAPDAB and other inhibitors reported in the literature.