Chalcone oxime derivatives as new inhibitors corrosion of carbon steel in 1?M HCl solution

Article abstract of DOI:10.1016/j.molliq.2021.116398

In this research, 1,3-diphenylprop-2-en-1-one oxime (CO) and 4-nitrophenyl-1-phenylprop-2-en-1-one(CO-NO₂) was synthesized and its adsorption properties and corrosion inhibition ability was evaluated for carbon steel (CS) in 1 M HCl at 293–323

Full text of DOI:10.1016/j.molliq.2021.116398

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Journal of Molecular Liquids 337 (2021) 116398
Contents lists available at ScienceDirect
Journal of Molecular Liquids
journal homepage: www.elsevier.com/locate/molliq
Chalcone oxime derivatives as new inhibitors corrosion of carbon steel in
1 M HCl solution
a
A. Thoume a,b, D. Benmessaoud Left a, A. Elmakssoudi b, F. Benhiba c, A. Zarrouk d, , N. Benzbiria ,
⇑
I. Warad e, M. Dakir b, M. Azzi a, M. Zertoubi a
a Laboratoire Interface Matériaux Environnement (LIME), Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, B.P 5366, Morocco
b Laboratoire de Synthèse Organique, Extraction et Valorisation (LSOEV), Faculté des Sciences Ain Chock, Université Hassan II de Casablanca, B.P 5366, Morocco
c Laboratory of Advanced Materials and Process Engineering, Faculty of Sciences, Ibn Tofail University, BP 242, 14000 Kenitra, Morocco
d Laboratory of Materials, Nanotechnology and Environment, Faculty of Sciences, Mohammed V University in Rabat, Av. Ibn Battouta, P.O. Box. 1014, Agdal-Rabat, Morocco
e Department of Chemistry and Earth Sciences, P.O. Box 2713, Qatar University, Doha, Qatar
a r t i c l e i n f o
a b s t r a c t
Article history:
In this research, 1,3-diphenylprop-2-en-1-one oxime (CO) and 4-nitrophenyl-1-phenylprop-2-en-1-one
(CO-NO2) was synthesized and its adsorption properties and corrosion inhibition ability was evaluated
for carbon steel (CS) in 1 M HCl at 293–323 K temperature using chemical and electrochemical tech-
niques such as weight loss measurements (WL), potentiodynamic polarization (PDP) and electrochemical
impedance spectroscopy (EIS). Results evince that the inhibition activity (IE%) enhances with the com-
pounds concentration and may achieve a maximum of 95 and 91% for CO and CO-NO2, respectively at
293 K. In obedience with PDP findings, the tested compounds act as some mixed-type inhibitors.
Survey of the temperature effect discloses that the inhibitory molecule is chemisorbed on carbon steel
substrate. The adsorption of CO and CO-NO2 occurs in accordance to the Langmuir’s isotherm.
Scanning Electron Microscopy (SEM) and UV–visible revealed the development of barrier film hindering
the access of aggressive ions into steel surface. The theoretical findings suggested by electronic/atomic
computer simulations supported the inhibitive chemicals interfacial adsorption through reactive centers.
Ó 2021 Elsevier B.V. All rights reserved.
Received 24 February 2021
Revised 21 April 2021
Accepted 1 May 2021
Available online 5 May 2021
Keywords:
Chalcone oxime derivatives
Carbon steel corrosion
Weight loss-electrochemical techniques
SEM/UV–visible
Theoretical calculations
1. Introduction
their possible toxicity and contamination risk, and existing law
prohibits the use of toxic substances [12–14]. Compounds organic
Corrosion is a phenomenon of considerable economic impor-
tance. It is well known that corrosion reduces the life cycle of met-
als [1,2], in particular steel, which is the most commonly used
metal. The repair costs and high productivity losses caused by cor-
rosion [3,4] effectively penalizes all of the industries in which acid
solutions are used. The major areas of employ are pickling or acid
cleaning, stimulation of oil wells, removal of localized deposits [5–
8]. Owing to the aggressiveness of such acid solutions, the area of
corrosion has evolved tremendously in recent years and is gradu-
ally directed towards the production of non-toxic, non-polluting
and stable Corrosion inhibitors, as far as prohibition is concerned
[9–11]. Corrosion inhibitors are chemicals, either inorganic or
organic, that, when applied to a corrosive medium, slow the corro-
sion process of the exposed surface. Corrosion inhibitors are classi-
fied into two important groups: organic and inorganic compounds.
Since most inorganic corrosion inhibitors are prohibited due to
inhibitor are the primary means of preventing metal corrosion in
hostile conditions. They are typically molecules that have heteroa-
toms of a single pair of electrons (N, O, and S) and/or aromatic
cycles of the conjugated structures p. It also has some notable fea-
tures, such as multi-functionality, enhanced film shaping capabili-
ties, and a wider surface cover [15–19]. Corrosion inhibition by
organic compounds results from their adsorption on the metal by
forming a protective layer on the metal surface. The adsorption
phenomena can be described mainly by two interaction types,
namely physical adsorption and chemisorption. Both types of
adsorption are influenced by the nature and charge of the metal,
the chemical structure of the organic product and the type of elec-
trolyte [20–23]. As the current available organic corrosion inhibi-
tors are becoming more and more dangerous, it is a matter of
urgency to find new environmentally friendly inhibitors. Chalcone
oxime has corrosion inhibiting properties and is therefore non-
toxic, soluble in water and comparatively inexpensive [24–28].
In the present survey, the adsorption behavior and the inhibi-
tory activity of a novel environmentally benign compound, chal-
⇑
Corresponding author.
E-mail address: azarrouk@gmail.com (A. Zarrouk).
https://doi.org/10.1016/j.molliq.2021.116398
0167-7322/Ó 2021 Elsevier B.V. All rights reserved.

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A. Thoume, D. Benmessaoud Left, A. Elmakssoudi et al.
Journal of Molecular Liquids 337 (2021) 116398
cone oxime derivatives, was examined for carbon steel in acidic
medium (1 M HCl) at a temperature domain ranging from 293 to
323 K. In depth analysis on the adsorption mechanism of corrosion
inhibitors were screened via., weight loss measurements, electro-
chemical techniques (PDP and EIS), as well as surface analysis by
Scanning Electron Microscopy (SEM) and UV–visible were com-
bined to evaluate the inhibition process. To gain basic findings
about interactions and surface adsorption of CO and CO-NO2, com-
puter simulations (quantum chemistry linked with classical mod-
eling) were applied.
1200. The specimens were then rinsed with distilled water and
degreased by acetone. Samples were maintained immersed in
1 M HCl medium containing diverse inhibitor concentrations from
4.48 ꢀ 10-4 M to 2.24 ꢀ 10-3 M at a variable temperature of 293–
323 K.
2.3. Weight loss measurements
Measurements of weight loss were performed in compliance
with the standard methods. The specimens (Lx = 1 cm, Ly = 1 cm
and Lz = 0.3 cm) were abraded using various abrasive papers
(200–1200) and then thoroughly rinsed out with distilled water
and cleansed with acetone. The carbon steel specimens were
immersed in 1 M HCl solution in absence and presence of the
investigated inhibitors (4 ꢀ 48 10-4 to 2 ꢀ 24 10-3 M) at 293 K for
6 h. Afterwards, the samples were extracted and cleaned with dis-
tilled water, acetone and hot ethanol to remove all organic matter.
2. Materials and methods
2.1. Synthesis of chalcone oxime derivatives
A mixture of chalcone derivatives (1 mmol), hydroxylamine
hydrochloride (1.5 mmol), anhydrous sodium sulphate (1 mmol)
was reflowed in ethanol (5 mL) while stirring (Scheme 1). Once
the reaction was completed (3 h), the resulting mixture was fil-
trated and the solvent was subjected to evaporation at reducing
pressure. Afterwards, distilled water (10 mL) and ethyl acetate
(10 mL ꢀ 3) were added for the extraction of the organic products.
Before filtration, anhydrous sodium sulfate was used to dry the
combined organic layers. The crude product was recovered by
evaporating the solvent at a low pressure. Column chromatogra-
phy over silica, eluted with petroleum ether was operated to purify
the product [29].
Then, the samples were weighed and the corrosion rate (
determined as follows [30]:
m
) was
D
S ꢀ t
W
m
¼
ð1Þ
m0
ꢂ
m
gW ð%Þ ¼
where
ꢀ 100
ð2Þ
m0
D
W denotes the average weight loss, S represents the sample
surface area (cm2), t stands for the immersion time (h), o and
m mdes-
ignate the values of corrosion rate (mg cmꢂ2 hꢂ1) in uninhibited
and inhibited media, respectively.
The spectral data results of chalcone oxime derivatives are gath-
ered in Table 1.
2.2. Materials
2.4. Atomic adsorption measurements
Weight percentage composition of the tested carbon steel C38
was as follows: Fe: Base; C: 0.350–0.390; Si: ꢁ 0.400; Mn: 0.50–
0.80; S: 0.015–0.035; Cr + Ni + Mo: ꢁ 0.63. Prior to immersion in
solutions, the steel samples were polished by SiC abrasive paper
having an incrementally finer grain size ranging from 200 to
This technique was operated to calculate the concentration of
Fe in 1 M HCl solution without and with inhibitors (4.48 ꢀ 10ꢂ4
to 2.24 ꢀ 10ꢂ3 M) at 293 K after the electrochemical measure-
ments. The values of the inhibition activity were determined from
the atomic adsorption results according to the following formula:
Scheme 1. Synthesis of the inhibitors chalcone oxime derivatives.
Table 1
Characterization of chalcone oxime derivatives.
Molecule
Characterization
1H NMR (300 MHz, CDCl3):
dppm : 11.29 (s, 1H, OH), 7.78 – 7.56 (m, 4H), 7.46 – 7.31 (m, 6H), 7.29 – 6.38 (m, 2H).13C NMR (75 MHz, CDCl3):
dppm :157.74 (C = N) ;139.76 (CH-CAr), 137.04(CAr) ;136.19(Cq-CH = CH), 134.79(Cq-C = N) ; 129.25–125.74 (CAr) ;
117.15(CH = CH-Cq).
IR (KBr) cmꢂ1:3450 (OH), 2300 (CH), 1620 (C = N), 1514 (C = C), 945 (N-O).
1,3-diphenylprop-2-en-1-one oxime
(CO)
1H NMR (300 MHz, CDCl3):
dppm : 10.98 (s, 1H), 8.23 – 8.14 (m, 2H), 7.85 – 7.75 (m, 2H), 7.61 – 7.49 (m, 2H), 7.52 – 7.40 (m, 3H), 7.27 (m, 1H), 7.16
(m, 1H).
13C NMR (75 MHz, CDCl3):
dppm :153.90 (C = N) ;147.70 (C-NO2) ;139.78(Cq-CH = CH) ;135.74 (CH-CAr), 128.83(CAr) ;128.59 ; 128.23(CAr) ; 127.24
(CAr) 124.60 (CAr) ; 123.10(CAr).
4-nitrophenyl-1-phenylprop-2-en-1-
one (CO-NO2)
IR (KBr) cmꢂ1:3430 (OH), 2290 (CH), 1610 (C = N), 1570 (Ar-NO2) 1508 (C = C), 940 (N-O).
2

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A. Thoume, D. Benmessaoud Left, A. Elmakssoudi et al.
Journal of Molecular Liquids 337 (2021) 116398
C0 ꢂ C
final geometry by means of the Gaussian 09 software suite at the
DFT level in a functional B3LYP implementing a 6-31G (d, p) basis
set [35].
gað%Þ ¼
ꢀ 100
ð3Þ
C0
Here C0 and C refer to the concentration of iron in the absence and
presence respectively of CO and CO-NO2 inhibitors.
The quantum descriptors like LUMO and HOMO energies, gap
energy (
quantum descriptors such as, ‘‘
can be calculated using the Eq. (9), fraction of electrons transferred
from the inhibitor molecule to the metal surface ‘‘ N110” can be
determined using Eq. (10), where the work function presents
the theoretical value of in the plan (1 1 0) of iron (
= 4.82 eV) and the represent the metallic bulk (
= 0 eV) [36], ‘‘
the nucleophilic indexes (Eq. (12)),.
DEgap) (Eq. (7)), electronegativity ‘‘
v” (Eq. (8)), and other
g
” is the global hardness which
2.5. Electrochemical measurements
D
The inhibitory activity of the investigated compound on carbon
steel corroding were examined through Potentiodynamic Polariza-
tion(PDP) and Electrochemical impedance spectroscopy(EIS) in
1 M HCl in absence and presence of CO and CO-NO2 concentrations
going from 4.48 ꢀ 10-4 to 2.24 ꢀ 10ꢂ3 M at various temperatures
293–323 K. A classical cell with a three electrodes configuration
was used in the present study. The working electrode consisted
of carbon steel, whereas a platinum grid and a saturated calomel
electrode (SCE) were employed as a counter and reference elec-
trodes, respectively. Before electrochemical tests, the working elec-
trode was immersed in 1 M HCl solution without and with
different inhibitors concentrations for 40 min at open circuit
potential (OCP). The PDP plots were drawn with a scan rate of
0.5 mV sꢂ1 at the standard potential range found by
adding 200 mV to the OCP. EIS spectra were recorded between
100 kHz and 10 mHz at OCP with an amplitude of 10 mV. Three
replicas of the trials were performed and the average values were
regarded. The inhibitory efficacy was assessed as follows [31,32]:
U
v
U
=
v
(Fe110
)
)
g
g (Fe110
x
” is the electrophilic indexes (Eq. (11)), and ‘‘
e
” is
D
Egap ¼ ELUMO ꢂ EHOMO
ð7Þ
ð8Þ
1
v
¼
¼
ðEHOMO þ ELUMO
Þ
Þ
2
1
2
g
ðEHOMO ꢂ ELUMO
ð9Þ
v
ꢂ vinh
U
2
ꢂ
vinh
ginh
Fe110
ꢀ
ꢁ
D
N110
¼
¼
ð10Þ
2
gFe
þ
ginh
110
v2
i0corr ꢂ icorr
x
¼
ð11Þ
ð12Þ
2g
gPð%Þ ¼
ꢀ 100
ð4Þ
i0corr
1
i0corr and icorr denote the corrosion current densities values in absence
and presence of the inhibitory molecule, respectively.
e
¼
x
Rip ꢂ Rbp
2.7.2. Molecular dynamics (MD) simulations
gEISð%Þ ¼
ꢀ 100
ð5Þ
Rpi
The adsorbed inhibitors CO and CO-NO2 neutral and unnatural
forms on the metal surface was established using the MD simula-
tion using Forcite module implemented in Materials Studio 8.0
software [37,38]. The study of these interactions of the molecules
with the Fe (1 1 0) surfaces was carried out from a simulation
box (22.34* 22.341* 35.13 Å3) with periodic boundary conditions.
The Fe (1 1 0) surface was presented with a six-layer slab model
in each layer representing a (11 ꢀ 11) unit cell. The constructed
simulation box is emptied by 20.13 Å3. This vacuum is occupied
by 500H2O, 5H3O+, 5Cl- and the inhibitory molecule. The tempera-
ture of the simulated system of 293 K was controlled by the Ander-
sen thermostat, NVT ensemble, with a simulation time of 400 ps
and a time step of 1.0 fs, all under the COMPASS force field [39].
where Rbp and Rip are polarization resistances obtained in the blank
and the inhibited solutions, respectively.
The surface coverage, h is expressed as:
gPð%Þ
h ¼
ð6Þ
100
gP is the inhibitory efficiency determined by PDP.
2.6. Scanning electron microscopic measurement (SEM)
Carbon steel surface was examined after 6 h of immersion in
1 M HCl free of an inhibitor, and with the optimum concentration
of CO and CO-NO2. Carbon steel samples were transferred from the
test media, rinsed with water and dried. The morphological aspect
of carbon steel surface was examined by SEM (FEI FEG 450).
3. Results and discussion
3.1. Weight loss measurements and atomic adsorption
Table 2 displays the values of weight loss trials, the calculated
2.7. Computational details
corrosion rates (m), and the inhibition efficacy (gw%) values with-
2.7.1. DFT calculations
out and with diverse concentrations of CO and CO-NO2 in 1 M
HCl at a temperature of 293 K for 6 h. The analysis of Table 2
encloses the subsidence of corrosion rate and increment of the
inhibitory efficiency with increasing CO and CO-NO2 concentra-
Quantum chemical calculations on the DFT approach have been
carried for CO and CO-NO2 neutral and protonated forms to pro-
vide an understanding of the key influence of molecular structures
and electronic characteristics on the inhibitory properties [33].
Moreover, this complementary theoretical part has been carried
out with the attempt to correlate the experimentally computed
corrosion inhibition for the inhibitors with the chemical reactivity
descriptors of the DFT calculations [34]. The lowest energy inhibi-
tor shapes were tested in the DFT calculations conducted under
pressure and in the gaseous phase. Additionally, the molecular
structures of the compounds studied have been optimized to the
tions. Maximal
gW values of 95 and 92% were reached in the pres-
ence of 2.24 ꢀ 10-3 M of CO and CO-NO2, respectively. Through the
increment of the blocked portion of the steel by the synthesized
inhibitors, the interaction between the metallic substrate and the
destructive solution can be prevented [40]. Interestingly, identical
results were found by atomic adsorption technique, where we
observed that the concentration of iron decreases in 1 M HCl by
the addition of CO and CO-NO2, which main role are not only to
3

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A. Thoume, D. Benmessaoud Left, A. Elmakssoudi et al.
Journal of Molecular Liquids 337 (2021) 116398
Table 2
Weight loss parameters and concentration of iron (ppm) in 1 M HCl containing various concentrations of CO and CO-NO2 at 293 K.
Concentration
mol/L
Weight loss
atomic adsorption
D
W
m
g
W(%)
C
g
a(%)
(mg)
(mg cmꢂ2 hꢂ1
)
(ppm)
CO
Blank
11.4
3.3
2.5
1.9
1.2
0.4
3.7
2.9
1.7
1.3
0.9
1.902
0.551
0.418
0.323
0.209
0.06
0.616
0.483
0.283
0.216
0.150
—
4.776
1.563
1.162
0.908
0.686
0.321
1.688
1.132
0.733
0.503
0.412
—
4.48 ꢀ 10-4
8.96 ꢀ 10-4
1.34 ꢀ 10-3
1.79 ꢀ 10-3
2.24 ꢀ 10-3
4.48 ꢀ 10-4
8.96 ꢀ 10-4
1.34 ꢀ 10-3
1.79 ꢀ 10-3
2.24 ꢀ 10-3
71
78
83
89
95
68
75
85
89
92
67
76
81
87
93
65
76
85
90
91
CO-NO2
increase the surface coverage area, but also to suppress the corro-
sion rate.
observations confirm the mixed character of the inhibitors (lower
than 85 mV) [42,43].
3.2.2. Electrochemical impedance spectroscopy measurements
Transient electrochemical methods and, in particular, electro-
chemical impedance spectroscopy enables to distinguish the ele-
mentary phenomena that are expected to evolve on the
metal/solution interface according to their kinetics. Fig. 2 encloses
the Nyquist diagrams recorded for the steel/solution interface at
corrosion potential in 1 M HCl in the absence and presence of CO
and CO-NO2. Table 4 gathers the corresponding electrochemical
impedance parameters. For all concentrations, the diagrams evince
the presence of a single semi-circle properly centered on the axis of
the impedance real part. The ray of these loops increases with
increasing inhibitors concentration. In general, the feature of these
type of spectra may be ascribed to charge transfer process on a
heterogeneous surface [44]. An equivalent circuit (Fig. 2) is used
to study the progressions involved in electrical response of the sys-
tem. The capacitance double layer (Cdl), a polarization resistance
(Rp) and electrical resistance (Re) forms the parts of the circuit.
Through the following Eq. (13), the impedance of a constant phase
element is explained. The Cdl value can be determined using Eq.
(14).
3.2. Electrochemical measurements
3.2.1. Potentiodynamic polarization curves
The polarization curves of the metal-solution interface are a
fundamental characteristic of electrochemical kinetics but only
account for the slowest stage of the overall process (transport of
material, adsorption of species on the electrode. . .) at the electro-
chemical interface. The cathodic and anodic polarization plots of
carbon steel in 1 M HCl medium without and with various concen-
trations of CO and CO-NO2 are depicted in Fig. 1. Note that the
curves were obtained after 40 min of immersion at Ecorr and a tem-
perature of 293 K. In the cathodic branch, one may notice that the
curves form quasi-parallel lines, suggesting that the addition of CO
and CO-NO2 to the acidic medium does not change the mechanism
of hydrogen evolution. The reduction of H+ ions on the carbon steel
occurs primarily through electron transfer process (pure activation
mechanism)[41]. From the study of Table 3 and the polarization
curves reported in Fig. 1, it can be seen that the introduction of
CO and CO-NO2 induces a subsidence in both anodic and cathodic
current densities, which is likely related to the prohibition of the
anodic dissolution of the metal and the cathodic evolution of H2.
Besides, Ecorr values move slightly towards more negative values
and the corrosion current densities (icorr) decrease as CO and CO-
NO2 concentration increases in the solution. Furthermore, both
the anodic and cathodic partial currents are also decreased. These
ZCPE ¼ Qꢂ1ðiwÞꢂn
ð13Þ
ð14Þ
ꢀ
ꢁ
1=n
Cdl
¼
Q ꢀ R1pꢂn
2
(CO-NO2)
(CO)
2
1
1
0
0
-1
-2
-3
-4
-5
-1
Blank
4.48×10-4
8.96×10-4
1.34×10-3
1.79×10-3
2.24×10-3
M
M
M
M
M
Blank
4.48×10-4
8.96×10-4
1.34×10-3
1.79×10-3
2.24×10-3
M
M
M
M
M
-2
-3
-4
-600
-550
-450
-400
-350
-300
-500 E (mV/SCE)
-600
-550
-500
-450
-400
-350
-300
E (mV/SCE)
Fig. 1. Potentiodynamic polarization plots of carbon steel in 1 M HCl solution in the absence and presence of the synthesized inhibitors for 40 min at 293 K.
4