M. Hrimla, L. Bahsis, A. Boutouil et al.
Journal of Molecular Structure 1231 (2021) 129895
for the adsorption phenomenon of MPTM, the adsorption models
of the title compound were tested during the corrosion prevention
process by using Freundlich, Langmuir, and Temkin methodologies
removed by simple filtration. The product was extracted with ethyl
acetate (3 × 10 mL). The combined organic extracts were washed
with saturated NaCl and dried with anhydrous MgSO . After re-
4
[
23,24]. Theoretical studies were employed to rationalize the ad-
moval of the organic solvent under reduced pressure, the residue
was purified by flash chromatography on silica gel using ethyl ac-
etate as an eluent to afford the desired product (Table 1).
sorption mechanism of the MPTM compound over the mild steel
surface.
The product was obtained as
Mp: 100-102 °C. FTIR (KBr) ν/cm 1
a brown solid. Yield: 89%.
−
2. Experimental section
:
3423.10, 3142, 1520.45
(
N-H stretch); 3023.66, 905.90 (=CH stretch); 2929.75, 2801.51,
2
.1. Materials and Methods
1448.47 (CH3 stretch); 1610.60 (C=C stretch); 1116.50, 1034.69 (C-O
stretch); 1314.16, 1216.25 (C-N stretch). 1H-NMR (CDCl , 300 MHz,
3
Morpholine, propargyl bromide, triethylamine, sodium azide
δ (ppm)) 2.51 (dd, J = 5.0, 3.5 Hz, 4H), 3.66 (dd, J= 5, 3.4 Hz,
4H), 3.68 (s, 3H, CH ), 3.80 (s, 2H, CH ), 6.95 (d, J = 9.1 Hz, 2H,
and 4-methoxyphenylamine were purchased from Sigma-Aldrich
and used as received. Anhydrous magnesium sulphate was used to
dry the organic extracts, and all volatile substances were removed
under reduced pressure. The reaction mixtures were monitored by
Thin Liquid Chromatography (TLC), using commercial glass backed
TLC plates (Merck Kieselgel60 F254). Revelation was done under an
ultraviolet lamp at 254 nm and the melting point was determined
using an Electrothermal 9100.
3
2
1
3
CH ), 7.56 (d, J = 9.1 Hz, 2H, CH ), 7.79 (s, 1H, CH
). C-
triazole
2
2
NMR [CDCl , 75 MHz, δ (ppm)], 53.4 (2 CH ), 53.6 (CH ), 55.6
3
2
2
(CH ), 66.8 (2 CH ), 114.8 (2 HCar), 121 (HCtriazole), 122 (2 HCar),
3
2
130.5 (Cq), 144.6 (Cq), 159.9 (Cq). HRMS (FAB+) m/z: Calcd for
N O : 275.1503 Found: 275.1511. (Figs. S1 and S2 in Support-
C
H
18
14
4
2
ing Information).
1
The nuclear magnetic resonance spectra of the proton ( H NMR,
2.3. Corrosion Inhibition Study
3
00 MHz) and carbon (13C NMR, 75 MHz) were recorded in deuter-
ated chloroform (CDCl ) on a Bruker Advance DPX 300 device at
2.3.1. Materials Preparation
3
room temperature with TMS as an internal standard. HRMS were
performed on a Varian MAT 311 (EI) or a high-resolution MS/MS
ZabSpec TOF Micromass (ESI). FTIR spectra were carried out on
The MS sample having the following chemical composition (wt
%): O (0.03); Mn (0.048); N (0.012); S (0.012); C (0.016); P (0.001)
and the balance was Fe was used to carry out the corrosion in-
hibition experiments. MS was cleaned with double distilled water,
degreased with acetone, washed again with doubly distilled wa-
ter, soaked in acetone and alcohol, and dried at room temperature.
All potential measurements in the experimental studies refer to
the saturated calomel electrode (SCE), and the counter electrode
an FTIR Nicolet 5700 spectrometer (4000-400 cm 1). The UV-Vis
spectra were done with a UV-6300 PC Double Beam spectropho-
tometer (200 to 800 nm). The SEM analyses of MS were performed
employing Field Emission Scanning Electron Microscopy (FESEM)
−
(VEGA3 TESCAN) previously and post-exposure to a hydrochloric
2
medium (1 M) in the absence and presence of the optimal concen-
tration of inhibitor for 24 h at 298 K. The accelerator beam energy
applied was 20 kV.
is a platinum plate with a surface area of 2 cm . The corrosive
medium tested was prepared with an analytical quality of HCl (37%
by weight), and deionized water. The concentration of MPTM used
was changed from 300 to 900 ppm.
2
2
.2. Synthesis of the 1,2,3-triazole compound
.2.1. Synthesis of 1-azido-4-methoxybenzene
2
.3.2. Gravimetric Measurements
Gravimetric measurements were carried out in a double-walled
4
-Methoxyphenylamine (13 mmol) was suspended in 80 mL of
glass cell fitted with a thermostat-cooled condenser. The steel sam-
3
hydrochloric acid (17%) at room temperature, and then ethanol was
added until a clear solution was obtained. The solution was cooled
to 0 °C, and small portions (1.5 eq) of NaNO2 were added. 1.5 eq
of NaN3 was slowly added after stirring for 15 minutes at 0 °C. The
mixture was kept under stirring for 2 hours at room temperature.
The reaction mixture was extracted with diethyl ether (3 × 80 mL).
The organic phase obtained was washed with a saturated solution
of NaHCO3 and NaCl (50 mL). After drying with anhydrous MgSO4,
the organic solvent was removed under reduced pressure, and the
ples employed (2 × 2 × 0.05 cm ) were carefully cleaned with
double distilled water, degreased with acetone, washed again with
doubly distilled water, soaked in acetone and alcohol, dried, and
then weighed by using an electronic scale. Subsequently, they have
been drenched in 1 M HCl solution with and without different con-
centrations of MPTM for 6 h at various temperatures (from 298
to 328 K), separately. Experimental tests were conducted in each
case, and the average weight loss was considered to estimate the
corrosion rate in mg cm 2
−
h
−1
and the inhibition efficiency (IE %)
w
desired 1-azido-4-methoxybenzene (1) was obtained as a brown
according to the following equation:
1
liquid without any further purification. H NMR (300 MHz, CDCl ):
3
CR − CR
o
δ (ppm) = 6.95 - 6.90 (m, 2H, CH), 6.88 - 6.83 (m, 2H, CH), 3.76
IEw (%) =
× 100
(1)
CR
o
(
s, 3H, OMe) [25,26].
where CRo and CR are the corrosion rates in the lack and presence
2
4
.2.2. Synthesis of
of the inhibitor, respectively.
-[1-(4-methoxy-phenyl)-1H-[1,2,3]triazol-4-ylmethyl]-morpholine
(
MPTM)
The reaction was carried out in two steps:(i) the nucleophilic
2.3.3. Electrochemical Methods
The electrochemical measurements were carried out using the
Voltalab 10 system (PGZ 100 radiometer) controlled by the corro-
sion analysis software Volta master 4. Firstly, the open circuit po-
tential (OCP) was determined by the immersion of the electrodes
in 1 M HCl for an hour, with and without the addition of inhibitor.
The impedance tests were executed in the interval of 100 kHz to
0.1 Hz, with an amplitude of 10 mV, using the AC signal at Eocp.
The electrochemical impedance parameters were obtained using
EC-Lab software Bio-Logic Science Instruments, Seyssinet-Pariset,
France. Next, the potentiodynamic polarization curves were carried
substitution reaction between morpholine and propargyl bromide,
and (ii) the CuAAC reaction between the obtained terminal alkyne
and azide. Initially, the nucleophilic substitution reaction was per-
formed as follows: a mixture of water (5 mL), Et N (1.5 mmol),
3
organic amine (morpholine) (0.5 mmol) and propargyl bromide
(
(
0.5 mmol) was stirred for 10 minutes at 80 °C. Then, Cu(OAc)2
5 mol%) and ascorbic acid (5 mol%) were added and the reaction
mixture was stirred at 80 °C for 4h. After compilation, the reac-
tion mixture was cooled to room temperature and Cu(OAc)2 was
2