European International Journal of Multidisciplinary Research
and Management Studies
39
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TYPE
Original Research
PAGE NO.
39-41
DOI
OPEN ACCESS
SUBMITED
11 April 2025
ACCEPTED
15 May 2025
PUBLISHED
30 June 2025
VOLUME
Vol.05 Issue06 2025
COPYRIGHT
© 2025 Original content from this work may be used under the terms
of the creative commons attributes 4.0 License.
Protective Action Of New
Amine-Containing
Inhibitors
Oserbaeva Alfiya Kurbanbaevna
Tashkent Institute of Chemical Technology, Tashkent 100011, Uzbekistan
Khoshimova Mushtariybegim Umidjon qizi
Tashkent Institute of Chemical Technology, Tashkent 100011, Uzbekistan
Abstract:
This study investigates the protective action of
newly
synthesized
amine-containing
corrosion
inhibitors derived from local raw materials and the
distillation residues of monoethanolamine vacuum
distillation in the chemical industry of Uzbekistan. It is
shown that a multi-component inhibitor containing
hydroxyethyldenediphosphonic acid (HEDP), sodium
hydroxide, zinc oxide, glycerin, water, and the vacuum
distillation residue of monoethanolamine (COMEA) can
be used to protect steel equipment and pipelines in the
oil and gas industry. Changes in the absorption spectra
intensity of active functional groups of the inhibitors
were studied using IR spectroscopy. Parameters such as
corrosion current, stationary potential, corrosion rate,
degree of protection, and effective activation energy
(∆E_eff) were determined.
KEYWORDS:
Inhibition, gravimetry, thermodynamics,
steel corrosion, inhibitor, protective mechanism,
activation energy, Gibbs energy, corrosion rate,
protective effect.
Introduction:
Corrosion inhibitors are used in all areas
of human activity: in the atmosphere and water, in fuel
extraction and transportation, in energy, construction,
and mechanical engineering. In most cases, corrosion
environments
—
especially natural ones
—
have a pH
close to neutral. Corrosion of metals in neutral aqueous
environments usually causes localized surface damage.
Among organic compounds, salts of carboxylic acids
(RCOOH), where R is an alkyl, heteroalkyl, alicyclic, or
aromatic group, are widely used as inhibitors in neutral
media [1]. The primary cause of damage and wear of
metal equipment and pipelines is corrosion destruction
European International Journal of Multidisciplinary Research
and Management Studies
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European International Journal of Multidisciplinary Research and Management Studies
in acidic and neutral environments. The aggressiveness
of the environment is largely determined by
mineralization degree, salt (anion) composition of
reservoir waters, and increases in content of H₂S, CO₂,
CO, S, R-SH, organic acids, temperature, and pH [2].
Uzbekistan imports corrosion inhibitors, and the
demand is high, especially in the chemical,
electrochemical, petrochemical, gas industries, and
water supply systems.
OBJECTS AND METHODS
The study focused on amine-containing inhibitors
synthesized from local raw materials. The inhibitors
(denoted IKA-1 to IKA-3) are transparent liquid masses
that dissolve well in water and acidic environments.
They do not form separate phases during storage and
are effective in both soft and hard water (hardness 2
–
18 mg-eq/L), which is typical across regions of
Uzbekistan.
The
inhibitors
were
tested
in
concentrations from 0.001% to 1.0% mass. The effect
of neutral media on the corrosion behavior of St.3 steel
was studied using gravimetric (mass loss) and
electrochemical methods. Corrosion rate (K), inhibition
coefficient, and protection fficiency (Z) were calculated
according to formulas from [3].
RESULTS AND DISCUSSION
Corrosion-electrochemical behavior of St.3 steel in
3·10⁻³ mol/L NaOH solution without (1), and with
inhibitors IKA-1 (2), IKA-2 (3), and IKA-3 (4), is shown in
Fig.1.
The results show that the inhibition efficiency of
inhibitors IKA-6, IKA-7, and IKA-8 in strongly alkaline-
saline solutions does not change with temperature. The
solution contains 3% NaOH + 3% NaCl, indicating
significant adsorption of metal samples on the surface
[4]. Fig. 1. Effect of temperature on inhibition efficiency
of IKA-6 (1), IKA-7 (2), IKA-8 (3) in 3% NaOH + 3% NaCl
solution.
As temperature increases, the mobility of hydroxyl and
chloride ions increases, resulting in greater adsorption
on the metal surface. This sharply inhibits
electrochemical corrosion processes and helps evaluate
inhibitor effectiveness. The level of protection (Z)
decreases slightly even at low temperatures. Higher
temperatures also lead to more salt and oxide layers
forming on the metal, which accelerate corrosion.
Inhibitors help by minimizing formation of these layers.
Thermodynamic parameters of corrosion inhibition of
St.3 and St.12 steel in alkaline-saline environments at
298 K were calculated using IKA-6, IKA-7, and IKA-8.
Table 1.
Thermodynamic parameters of St.12 steel corrosion in 3% NaOH + 3% NaCl (T=298K, C_ing=1.0%)
Inhibitor
E_act
(kJ/mol)
∆H (J/mol)
∆S (J/mol·K)
Background
40.87
41.52
74.82
IKA-6
60.39
-44.31
41.25
IKA-7
64.43
-43.98
44.84
IKA-8
72.09
-45.43
48.34
Table 2.
Thermodynamic parameters of St.12 steel corrosion in 3% NaOH + 3% NaCl (T=298K, C_ing=1.0%)
Inhibitor
E_act (kJ/mol)
∆H (J/mol)
∆S (kJ/mol)
Background
42.51
43.05
48.84
IKA-6
65.58
-59.43
50.52
IKA-7
68.33
-57.31
52.18
IKA-8
78.48
-55.98
54.82
Stronger inhibitor films result in reduced influence of
active ions. The ∆H values of 55.9 and 45.4 kJ/mol (with
and without inhibitors, respectively) indicate an
exothermic corrosion process. Higher ∆H values in the
presence of inhibitors suggest chemical interaction
between inhibitor molecules and metal ions, forming
insoluble complex films. The increase in ∆S (from 48.8
to 54.82 J/mol·K) also confirms complexation. Higher
E_act indicates that inhibitors raise energy barriers at
the cathode and anode, reducing corrosion.
CONCLUSION
Studies of St.3 steel corrosion in acidic and hydrogen
sulfide environments in the presence of amine- and
phosphate-containing inhibitors showed high efficiency.
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European International Journal of Multidisciplinary Research and Management Studies
The best inhibitor was found to be diethylaminoethyl
methacrylate phosphate among alkylamines, likely due
to the high number and size of radicals, requiring the
lowest protective concentration compared to other
tested amines.
REFERENCES
1.
Bober Y.G. Corrosion Inhibition of Iron in Neutral
Media with Substituted Phenylanthranilic Acid
Salts, Moscow, 2009.
2.
Kuznetsov Yu.I., Vagarov R.K. Protection of Metals,
2000, Vol. 36, No. 5, p. 520.
3.
Oserbaeva A.K., Nurullaev Sh.P., Kodirov Kh.I.
Protection of Steel from Corrosion in Acidic and
Neutral Environments, Universum: Chemistry and
Biology, No. 11 (53), 2018, pp. 58
–
61.
4.
Oserbaeva A., Ismailova N., Ayimbetov M.
Isotherms of Adsorption Process in Hydrogen
Sulfide Medium, International Journal of Materials
and Chemistry, Nov. 2023
