ANALYSIS OF FATTY ACIDS IN DIVERSE OIL SAMPLES

SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 96 ANALYSIS OF FATTY ACIDS IN DIVERSE OIL SAMPLES D.H. Nazirova1, G.Kh. Boltaeva2, Y.S. Erkhonova3 National University of Uzbekistan1,2,3 https://doi.org/10.5281/zenodo.17518293 Abstract. The following studies were performed in this paper: extraction of fatty acids from vegetable and animal fats and determination of their fatty acid composition; synthesis of inorganic PSMs based on fatty acid mixtures and analysis of the synthesized substances; determination of the hydrophilic-lipophilic balance and critical micelle concentration (CMC) of the synthesized PSMs; study of foaming capacity and foam stability, as well as the ability to form oil-in-water emulsions; analysis of the PSMs' oil film removal activity, including a study of the temperature dependence of oil washout efficiency and the effect of electrolyte salts on oil washout efficiency. Keywords: off-gas processing, aqueous surfactant solutions, oaming, and stabilizing properties. Introduction It has been firmly established that one of the main challenges in off-gas processing is oil dehydration and desalination. This process is associated, in particular, with an increase in the water and salt content of the produced oil, which negatively impacts the quality of the final product, as well as the equipment used for its transportation and processing. The cleaning action of aqueous surfactant solutions is widely used in everyday life and in various technological processes, including oil dehydration and desalination. Therefore, it is necessary to establish the relationship between the cleaning action of aqueous surfactant solutions and the efficiency of oil dehydration and desalination. It is important to conduct scientific and practical research into the development of new surfactant-based detergents (PSMs) with cleaning, foaming, and stabilizing properties. Therefore, special attention is being paid to the production and study of new PSMs based on natural and local raw materials and industrial waste, determining their effectiveness in emulsification, demulsification, and oil slick removal processes, studying synthesis processes, determining the composition and properties of the resulting PSMs, developing and testing their production technology, selecting effective formulations, and preventing potential negative environmental impacts. Of particular significance is the fact that various vegetable oils, including sunflower, cottonseed, and coconut oils, as well as animal fats such as sheepskin fat and viscera, were used as feedstock for the production of PSMs. The following experiment was conducted to separate fatty acids from fat. Initially, 95.1 g of NaOH was dissolved in 1000 ml of water, and the solution temperature was raised to 70°C. Then, 740 g of animal viscera fat was added to the heated solution, and the resulting mixture was heated for 6 hours with vigorous stirring. To prepare a 20% sulfuric acid solution, 118.5 g of 94.5% sulfuric acid solution was measured and 445.5 g of water was added. СН2(-О-СО-R)-CH(-О-СО-R)-CH2(-О-СО-R)+NaOH→ RCOONa + CH2(ОН)-СН(ОН)-СН2(ОН) RCOONa + H2SO4 → RCOOH + Na2SO4 SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 97 It is crucial to recognize that 560 g of sulfuric acid solution was used to re-acidify the resulting soap. This process converted the soap into fatty acid. Litmus paper was used as an indicator to determine the completion of the reaction; the process was stopped when the litmus paper turned red. The reaction of diethanolamine with fatty acids was carried out in a solvent-free system with a molar ratio of 1.0:1.0. An Al2O3 catalyst was added to this system at a rate of 1% of the fatty acid mass. The reactions were carried out in a three-necked round-bottomed flask under an N2 atmosphere. The reaction mixture was heated to 70°C for half an hour, then the temperature was increased to 140°C. The reaction mixture was stirred in a laboratory stirrer at 200 rpm. The reaction was complete after 3 hours. Fatty diethanolamide was isolated by separating the amides from excess substrate by distillation at a residual column pressure of 75 ± 1 mmHg or by washing with acetone. The reaction progress was monitored by measuring the acid value every hour until constant values were reached. The product yield ranged from 93% to 97%. RCOOH + NH(C2H4OH)2 → RCON(C2H4OH)2 + H2O The synthesized PSMs were given the designations PAVMS, PAVXS, PAVKM, PAVKJ, and PAVVJ. Chromatographic analysis of the fatty acids was performed to determine the fatty acid composition. Table 1 Qualitative and quantitative analysis of sunflower oil fatty acids № Substance name Quantity, % Compatibility with hardware base 1. Tetradecanoic acid 0,05 96 2. Hexadecanoic acid 6,72 95 3. 9,12-Octadecadienoic acid 60,26 99 4. 9-Octadecenic acid 28,64 99 5. Octadecanoic acid 3,87 98 6. Eicosanoic acid 0,18 96 7. Docosanoic acid 0,21 95 8. Docosahexaenoic acid 0,07 90 As the table shows, sunflower oil consists primarily of the fatty acids 9,12-octadecadienoic acid (60.26%) and 9-octadecanoic acid (28.64%). Cottonseed oil also contains 9,12octadecadienoic acid (45.43%). Hexadecanoic acid is also present (28.76%). Table 2 Quantitative analysis of fatty acids in cottonseed oil № Substance name Quantity, % Compatibility with hardware base 1. Tetradecanoic acid 0,68 95 2. Hexadecanoic acid 28,76 97 3. 9,12-octadecadienoic acid 45,43 98 4. 9-octadeconic acid 21,42 96 5. Octadecanoic acid 3,22 98 6. Eicosanoic acid 0,40 95 7. Docosanoic acid 0,09 93 SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 98 It should be emphasized that the main fatty acid in coconut oil is dodecanoic acid (50.58%). It also contains a significant amount of tetradecanoic acid (25.51%). Coconut oil has a significantly different fatty acid profile compared to sunflower and cottonseed oils. Coconut oil is dominated by short-chain saturated fatty acids, such as decanoic (capric), dodecanoic (lauric), and tetradecanoic (myristic) acids, which contribute to its unique properties. Table 3 Quantitative analysis of fatty acids in coconut oil № Substance name Quantity, % Compatibility with hardware base 1. Decanoic acid 5,08 90 2. Dodecanoic acid 50,58 90 3. Tetradecanoic acid 25,51 97 4. Hexadecanoic acid 8,69 96 5. 9,12-octadecadienoic acid 1,18 98 6. 9-octadeconic acid 6,29 99 7. Octadecanoic acid 2,97 95 The high proportion of saturated fatty acids in coconut oil (92.83%) differs significantly from that in sunflower and cottonseed oils, which are dominated by long-chain and polyunsaturated fatty acids such as linoleic and oleic acids. The composition of tail fat and intestinal fat was also studied: tail fat has a relatively balanced ratio of saturated and unsaturated fatty acids (approximately 52% and 48%, respectively), which differs from the high saturated fatty acid content in coconut oil (approximately 93%) and the predominance of unsaturated acids in cottonseed and sunflower oils. It has been established that tail fat has a high oleic acid content – 43.14%. The main fatty acid in visceral fat is stearic acid, with a content of 45.26%, significantly exceeding that of other fatty acids. The total saturated fatty acid content was 71.25%, significantly exceeding the unsaturated fatty acid content (28.75%). Based on the data obtained, the molecular weight of the fatty acid mixture of the studied samples was calculated and found to be: 279.06 g/mol for sunflower oil, 272.55 g/mol for cottonseed oil, 219.78 g/mol for coconut oil, 271.88 g/mol for lard, and 272.1 g/mol for visceral animal fats. The following results were obtained during the study: optimal conditions for the extraction of fatty acids from natural fats and oils were determined. These were achieved by dissolving animal fat or vegetable oil in a NaOH solution, heating the mixture at 70°C for 5-6 hours, and then treating it with a 94.5% sulfuric acid solution. The successful synthesis of N,Nbis(hydroxyethyl)alkanamide from the obtained fatty acids and diethanolamine was carried out in a solvent-free system using an Al2O3 catalyst, achieving product yields of up to 97%. It is important to highlight that low CMC and cloud point values for PAVMS, PAVKS, and PAVKM indicate their high efficiency and applicability under various conditions. These PSMs rapidly form micelles at low concentrations, and their solutions can be maintained stable over a wide temperature range. The effect of the hydrophobic alkyl chain of the PSMs on surface tension confirms that longer and more saturated alkyl chains enhance the lipophilic properties (PAVBJ and PAVKJ) and reduce hydrophilicity. A study of the foaming properties of various synthesized surfactants showed that foam height increased significantly with increasing surfactant concentration. At a 1.0% concentration of PAVC, the maximum foam height was recorded, reaching 270 mm, and high foam stability was achieved, remaining at 160 mm after 5 minutes of SCIENCE AND INNOVATION INTERNATIONAL SCIENTIFIC JOURNAL VOLUME 4 ISSUE 10 OCTOBER 2025 ISSN: 2181-3337 | SCIENTISTS.UZ 99 foam formation. Meanwhile, the PAVC obtained from animal fat demonstrated relatively low foam height but high foam stability. The PAVC and PAVC showed moderate foam height, but the PAVC demonstrated greater foam stability, indicating the strength of the foam formed. The PAVC obtained from animal fat produced the lowest foam height but was highly stable due to the long-chain saturated fatty acids, which reduced foaming ability but increased foam stability. It was found that adding surfactants at a concentration of 0.5% resulted in significantly faster removal of the oil film from the glass surface, confirming the hydrophobic effect of surfactant molecules on film removal. Water removed only 11% of the oil film in 500 seconds, but the efficiency of the surfactants was significantly higher, reaching a maximum of 98.3% for the PAVCMS. Conclusion. It is necessary to consider that non-ionic surfactants, such as Neonol, PAVMs, PAVCs, and PAVCs, exhibit a significant increase in cleaning performance with an increase in temperature from 15°C to 25°C and a stability of 80–90%. Furthermore, ionic surfactants, such as sodium laureth sulfate and sodium dodecylbenzenesulfonate, require high temperatures to activate their cleaning properties, confirming the economic and environmental effectiveness of non-ionic surfactants synthesized from locally available raw materials. REFERENCES 1. Поверхностно-активные вещества и композиции: справочник. Под ред. М. Ю. Плетнева. – М.: ООО «Фирма Клавель», 2002. – 768 с. 2. Rosen, M. J. Surfactants and interfacial Phenomena / M. J. Rosen, J.T. Kunjappu. – 4th ed., updated and revised. – N.Y.: J.Wiley & Sons, 2012. – 616 p. 3. Ланге, К. Р. Поверхностно-активные вещества: синтез, свойства, анализ, применение / К.Р.Ланге; науч. ред. Л. П. Зайченко; пер. с англ. 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