Protective Action Of New Amine-Containing Inhibitors

Аннотация

This study investigates the protective action of newly synthesized amine-containing corrosion COPYRIGHT inhibitors derived from local raw materials and the © 2025 Original content from this work may be used under the terms distillation residues of monoethanolamine vacuum of the creative commons attributes 4.0 License. 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 33 https://eipublication.com/index.php/eijmrms and Management Studies European International Journal of Multidisciplinary Research and Management Studies in acidic and neutral environments. The aggressiveness Corrosion-electrochemical behavior of St.3 steel in of the environment is largely determined by 3·10⁻³ mol/L NaOH solution without (1), and with mineralization degree, salt (anion) composition of inhibitors IKA-1 (2), IKA-2 (3), and IKA-3 (4), is shown in reservoir waters, and increases in content of H₂S, CO₂, Fig.1. CO, S, R-SH, organic acids, temperature, and pH [2]. The results show that the inhibition efficiency of Uzbekistan imports corrosion inhibitors, and the inhibitors IKA-6, IKA-7, and IKA-8 in strongly alkaline- demand is high, especially in the chemical, saline solutions does not change with temperature. The electrochemical, petrochemical, gas industries, and solution contains 3% NaOH + 3% NaCl, indicating water supply systems. significant adsorption of metal samples on the surface OBJECTS AND METHODS [4]. Fig. 1. Effect of temperature on inhibition efficiency of IKA-6 (1), IKA-7 (2), IKA-8 (3) in 3% NaOH + 3% NaCl The study focused on amine-containing inhibitors solution. synthesized from local raw materials. The inhibitors (denoted IKA-1 to IKA-3) are transparent liquid masses As temperature increases, the mobility of hydroxyl and that dissolve well in water and acidic environments. chloride ions increases, resulting in greater adsorption They do not form separate phases during storage and on the metal surface. This sharply inhibits are effective in both soft and hard water (hardness 2– electrochemical corrosion processes and helps evaluate 18 mg-eq/L), which is typical across regions of inhibitor effectiveness. The level of protection (Z) Uzbekistan. The inhibitors were tested in decreases slightly even at low temperatures. Higher concentrations from 0.001% to 1.0% mass. The effect temperatures also lead to more salt and oxide layers of neutral media on the corrosion behavior of St.3 steel forming on the metal, which accelerate corrosion. was studied using gravimetric (mass loss) and Inhibitors help by minimizing formation of these layers. electrochemical methods. Corrosion rate (K), inhibition Thermodynamic parameters of corrosion inhibition of coefficient, and protection fficiency (Z) were calculated St.3 and St.12 steel in alkaline-saline environments at according to formulas from [3]. 298 K were calculated using IKA-6, IKA-7, and IKA-8. RESULTS AND DISCUSSION Table 1. Thermodynamic parameters of St.12 steel corrosion in 3% NaOH + 3% NaCl (T=298K, C_ing=1.0%) E_act Inhibitor ∆H (J/mol) ∆S (J/mol·K) (kJ/mol) 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 to 54.82 J/mol·K) also confirms complexation. Higher Stronger inhibitor films result in reduced influence of E_act indicates that inhibitor