Anti-corrosion behavior of 2-((3-(2-morpholino ethylamino) -N3-((pyridine-2-yl)methyl)propylimino)methyl)pyridine and its reduced form on Carbon Steel in Hydrochloric Acid solution: Experimental and theoretical studies
Abstract
A comparative investigation of the corrosion inhibition of two ligands, 2-((3-(2-morpholinoethylamino)-N3-
((pyridine-2-yl)methyl) propylimino) methyl)pyridine (SB) and N1-(2-morpholinoethyl)-N1,N3-bis(pyridine-2-
ylmethyl)propane-1,3-diamine (RSB) for carbon steel in 1.0 M HCl has been carried out. The inhibitor effects on
the corrosion behavior of the samples were determined at three different concentrations, 0.1, 1.0 and 2.0 mM.
Electrochemical analyses, including corrosion potential and electrochemical impedance spectroscopy (EIS), were
utilized to study the corrosion behavior of carbon steel in inhibitor-free and inhibitor-containing electrolytes. The
corrosion potential results showed a gradual increment from 450 to 421 mV vs. Ag/AgCl, in the range of 0.2
2.0 mM SB concentration. In addition, the corrosion potential of carbon steel in RSB containing solutions is in
the range of 439 to 434 mV vs. Ag/AgCl, which results confirm that a higher concentration of SB promotes the
inhibition efficiency of samples in 1.0 M HCl solution. The results showed that SB had better inhibition efficiency
(around 82.1% at the concentration of 2.0 mM) than RSB. The SB inhibitor exhibited a Langmuir adsorption
isotherm, while the adsorption of the RSB did not follow the Langmuir model. EIS studies demonstrated that the
addition inhibitors decrease the capacitance of the double layer and increase the resistance of charge transfer.
Anticorrosive properties of SB and RSB molecules are examined in detail by using Hartree–Fock (HF) method,
Becke, 3-parameter, Lee–Yang–Parr (B3LyP) method, and M062X (highly parameterized, exchange correlation
function) methods.