| dc.description.abstract | The effect of new compounds containing morpholine moiety including: 3,5-di-tert-butyl-2-(((3-((2-morpholinoethyl)(
pyridine-2-ylmethyl)amino)propyl)imino)methyl)phenol (L1) and its reduced form, 3,5-di-tert-butyl-2-(((3-
((2-morpholinoethyl)(pyridine-2-ylmethyl)amino)propyl)amino) methyl)phenol (L2) on the corrosion inhibiting of Csteel
in 1.0 M HCl and 3.5 wt% NaCl was tested by experimental and computational techniques. The concentration
of inhibitor varied in the range of 0.2–2.0 mM. The corrosion behavior of C-steel was investigated using
electrochemical techniques, including open circuit potential (OCP), potentiodynamic polarization (Tafel), electrochemical
impedance spectroscopy (EIS) and scanning electron microscopy (SEM) inhibitor-free and inhibitorcontaining
solutions. From the Tafel diagram, the icorr of the C-steel electrode in the 1.0 M hydrochloric acid
solution represents the highest value among the other inhibitor-containing solutions. The icorr for C-steel in L1
containing solution decreases gradually from 1.43 × 10 4 to 0.91 × 10 4 A/cm2, with the concentration of L1
increasing from 0.2 to 2.0 mM. Along with the increase of the L2 concentration from 0.2 to 2.0 mM, the icorr is
reduced by about 41%. EIS studies demonstrated that the capacitance of the double layer increased by the
addition of inhibitors and increasing the resistance of charge transfer, suggesting an improvement of the
corrosion protection in inhibitor-containing acidic solution. SEM images confirmed the corrosion results in which inhibitor-containing solution protects the C-steel surface against the attack of species. The results showed that in
all solutions containing equivalent concentrations of inhibitors, the reduced form of L1 had a better inhibition
efficiency than the L1 inhibitor. Inhibitors, L1 and its reduced form exhibit Langmuir adsorption isotherm, in
which monolayer adsorption of inhibitors is carried out on the C-steel electrode. The properties of the studied
molecules to be corrosion inhibitors were examined with the Gaussian software program. The calculations of the
molecules were made in different methods and basis sets. | tr |
