VOLUME NR 3

PHYSICAL CHEMISTRY

UDK 541.138+541.135.3

S. N. Rasulova, V. P. Guro, U. N. Ruziev, Kh. T. Sharipov, М. А. Ibragimova, E. T. Safarov

COMPARISON OF THE PROCESSES OF SODA AND AMMONIA LEACHING OF THE INDUSTRIAL MOLYBDENUM PRODUCT. PART 1

Institute of General and Inorganic Chemistry of the Academy of Sciences of the Republic of Uzbekistan

Abstract. Background. At Almalyk MMC JSC molybdenum middling cinder is processed in soda medium by leaching. The role of metal ion ligands in the leaching of valuable components from Mo-cinder has not been adequately studied.

Purpose: to obtain comparative characteristics of the processes of soda and ammonia leaching of molybdenum middling cinder.

Methodology. The composition of the cinder samples and the solutions and cakes formed during leaching was controlled spectrometrically (ААС Perkin-Elmer 3030В, ICP-Agilent 7500 IСP). The leaching of the cinder was carried out according to soda and ammonia schemes.

Originality. It is shown that the loss of Au, Ag from the leaching cakes of Mo-cinder is 20% and 34%, respectively, in the ammonia scheme, and 22% and 14%, respectively, in the soda scheme. The possibility of direct transfer of Au and Ag from PPM cinder into diphenylguanidine solution is shown.

Findings. The leaching of molybdenum middling cinder in soda and ammonia schemes was studied. The composition of cakes and leaching solutions has been studied.

Key words: sulfide mineral, molybdenum, gold, silver, cinder, Mo-concentrate, cake, soda, ammonia, leaching.

Highlights:

- soda leaching of PPM cinder has been studied;

- ammonia leaching of PPM cinder has been studied too;

- comparative characteristics of efficiency and losses were obtained.

References

1. Bulenbaev M.Zh. Development of technology for extracting gold from refractory gold-bearing raw materials: Dissertation ... uch. Art. PhD, Almaty. - 2015. - 138 p. (in Russian)

2. Patent of the Russian Federation No. 2087568. Method for extracting noble metals from ores and materials. Gurov V.A.; Appl.: 1996-07-09; publ. 08/20/1997. (in Russian)

3. Patent of the Russian Federation No. 2120487. Method for processing gold-bearing raw materials. Melnichenko E.I., Moiseenko V.G., Sergienko V.I. et al. Appl.: 1997-12-23; publ. 10/20/1998. (in Russian)

4. Zharkenov M.I., Toktamysov M.T., Satybaldin O.B. Efficiency of leaching of dump and poor ores of non-ferrous and ferrous metals of Kazakhstan.- Almaty: KazGOSINTI, 1993.-S. 150. (in Russian)

5. RF patent No. 2090637. Method for extracting precious metals from ores. Gurov V.A.; Priorities: declared: 1996-07-09; publ. 09/20/1997. (in Russian)

6. RF patent No. 2117709. Method for oxidative autoclave leaching of polymetallic ferrosulfide materials containing precious metals. Korsunsky V.I., Timoshenko E.M., Naftal M.N. et al. Appl.: 1997-10-13; publ.: 20.08.1998. (in Russian)

7. RF patent No. 2119963. Method for extracting gold from refractory ores and concentrates. Blumberg E.A., Son S.B.; Appl.: 1997-08-26; publ. 10/10/1998. (in Russian)

8. RF patent No. 2087568. Method for extracting noble metals from ores and materials. Gurov V.A. Appl.: 1996-07-09; publ.: 20.08.1997. (in Russian)

9. Extraction of molybdenum from sulfide ore with an alkaline solution of sodium hypochlorite / V.I. Lutsik, Yu.M. Potashnikov, V.A. Lutsik and others // Izv. Sib. otd. Academy of Sciences of the USSR. Ser. chem. Sciences. - T. 4. - 1985. - No. 11. - S. 49-54. (in Russian)

10. Potashnikov Yu.M., Lutsik V.I., Lutsik V.A. Behavior of pyrite in sodium hypochlorite solutions. Izvestiya vuzov. Non-ferrous metallurgy. - 1987. - No. 3. - S. 45-48. (in Russian)

11. Zelikman A.N. Molybdenum. - M.: Metallurgy, 1970.-S. 21, 407-408. (in Russian)

12. Potashnikov Yu.M., Lutsik V.I., Chursanov Yu.V. Study of the interaction of molybdenite with nitric acid.// Izvestiya vuzov. Non-ferrous metallurgy.-1984.- No. 1.–C.57-61.

13. Patent RU 2441084 C2. Method for processing molybdenite concentrate. Author(s): Lobanov V.G.(RU), Sitdikov F.G.(RU), Mavrin I.N.(RU) et al. Application: 2010108195/02, 04.03.2010. Starting date of the patent validity period: 03/04/2010. (in Russian)

14. Patent RU 2393253. Method for processing sulfide and mixed molybdenum-containing concentrates for the extraction of molybdenum and rhenium. Vatolin N.A., Khalezov B.D., Lobanov V.G. etc. Starting date of the patent: 06/08/2009, Published: 06/27/2010. Bull. no 18. (in Russian)

15. Patent RU 2696989 C1. Method for processing molybdenite-containing concentrates. Antropova I. G. (RU). Submission: 2018.10.15. Start date: 2018.10.15. Publication: 2019.08.08, bul. no 22. (in Russian)

16. Ts 00193950-074:2018. Molybdenum middling cinder.-T.: Uzstandart, 2018.-12 p. (in Russian)

17. A. L. Samusev and V. G. Minenko, Productivity of Chemical–Electrochemical Gold Leaching from Rebellious Ore, ISSN 1062-7391.// Journal of Mining Science.- 2014.-V. 50.-No. 1.-Rp. 171–175. DOI: 10.1134/S1062739114010232.

18. Leontyeva E. V. Development of technology for the extraction of gold and silver by chemical processing of stale tailings of flotation of copper-zinc pyrite ores: Abstract. Magnitogorsk, 24 May 2017. (in Russian).

To cite this article: S. N. Rasulova, V. P. Guro, U. N. Ruziev, Kh. T. Sharipov, М. А. Ibragimova, E. T. Safarov. Comparison of the processes of soda and ammonia leaching of the industrial molybdenum product. Part 1 // Uzbek chemical journal. -2022. – Nr3. - Pp.3-9.

Received: 25.04.2022; Accepted: 10.05.2022; Published: 30.06.2022

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UDK669.715:620.193

U. R. Jobirov, Firuzi Hamroqul, I. N. Ganiev, Z. R. Obidov

OXIDATION KINETICS OF Zn0.5Al ZINC ALLOY, DOPED WITH YTTRIUM AND PRASEODYMIUM

Institute of Chemistry of the National Academy of Sciences Tajikistan, Dushanbe c., Е-mail: obidovzr@gmail.com

Abstract. Background. Most elements form solid solutions of variable concentrations with Al and Zn, which leads to a change in the physicochemical properties. The relevance of the study is associated with the need to study the processes of interaction of metal alloys with gaseous and aggressive media at elevated temperatures.

Purpose. Study of the oxidation kinetics of Zn0.5Al zinc alloy, doped with yttrium and praseodymium, in the solid state.

Methodology. The thermogravimetric method was used to study the effect of alloying additions (0.01÷1.0 wt%) of yttrium and praseodymium on the oxidation kinetics of Zn0.5Al zinc alloy in the temperature range of 523–623 K.

Originality. It has been established that Y and Pr additions within the range of 0.01÷0.05% significantly reduce the oxidizability of the Zn0.5Al zinc alloy. Alloy oxidation products are ZnO, Al₂O₃, Y₂O₃, Pr₂O₃, ZnAl₂O₄, Al₂O₃•Y₂O₃.

Findings. At a temperature of 523–623 K, the values of the oxidation rate of the zinc alloy Zn0.5Al doped with yttrium and praseodymium were determined. The behavior of doped alloys by the third component differs significantly from the oxidation of the binary Zn0.5Al alloy.

Key words: zinc alloy Zn0.5Al, yttrium, praseodymium, thermogravimetric method, oxidation kinetics, activation energy.

Highlights:

- studied oxidation kinetics of Zn0.5Al-Y and Zn0.5Al-Pr alloys systems.

- calculated kinetic and energy parameters of the oxidation process.

- used thermogravimetric method and X-ray phase analysis.

References

1. Vitkin A.I., Teindl I.I. Metallic coatings of sheet and strip steel. -M.: Metallurgy, 1971.- 493 p. (in Russian)

2. Menshikov I.A., Lukyanova N.V., Shein A.B. Protection of steel from corrosion in acidic media at elevated temperatures by "Soling" series inhibitors // News of higher educational institutions Chem. Chem. Tekhnol.- 2019.-V. 62.- N 4. P. 103-110.

3. Uesugi T., Takigawa Y., Kawasaki M., Higashi K. Achieving room-temperature superplasticity in an ultrafin-grainer Zn-22% Al alloy // Letters on materials. -2015.- N 5(3).- P. 269–275.

4. Lin K.L., Yang C.F., Lee J.T. Correlation of microstructure with corrosion and electrochemical behaviors of the bach-type hot-dip Al-Zn coatings: Part 1. Zn and 5% Al-Zn coatings // Corrosion.-1991.-Vol. 47.-N 4.-P. 9-13.

5. Mazilkin A.A., Straumal B.B., Borodachenkova M.V., Valiev R.Z., Kogtenkova O.A., Baretzky B. Gradual softening of Al-Zn alloys during high-pressure torsion // Materials Letters. -2012.-Vol. 84.-P. 63–65.

6. Kechin V.A., Lyublinskii E.Ya. Zinc alloys.-M.: Metallurgy, 1986.-247 p. (in Russian)

7. Maniram S.G., Singh G.M., Dehiya S., Sharma N.C. Effect of fly ash articles on the mechanical properties of Zn-22% Al alloy via stir castimg method // IOSR Journal of Mechanical and Civil Engineering.-2013.-Vol.-10. Issue 2.- P. 39–42.

8. Obidov Z.R. Effect of pH on the Anodic Behavior of Beryllium and Magnesium Doped Alloy Zn55Al // Russian Journal of Applied Chemistry.-2015.-V. 88.-N 9.-P. 1451–1457

9. Lin K.L., Yang C.F., Lee J.T. Correlation of microstructure with corrosion and electrochemical behaviors of the bach-type hot-dip Al-Zn coatings: Part 2. 55% Al-Zn coatings // Corrosion.-1991.-Vol. 47.-N 4.-P. 17-30.

10. Obidov Z.R. Thermophysical Properties and Thermodynamic Functions of the Beryllium, Magnesium and Praseodymium Alloyed Zn-55Al Alloy // High Temperature.-2017.-V. 55.-N 1.- P. 150–153.

11. Obidov Z.R. Anodic Behavior and Oxidation of Strontium-Doped Zn5Al and Zn55Al Alloys // Protection of Metals and Physical Chemistry of Surfaces.-2012.-V. 48.- N 3.- R. 352-355.

12. Vasiliev E.K., Nazmansov M.S. Qualitative X-ray diffraction analysis. -Novosibirsk: Nauka, 1986.-200 p. (in Russian)

To cite this article: U. R. Jobirov, Firuzi Hamroqul, I. N. Ganiev, Z. R. Obidov. Oxidation kinetics of Zn0.5Al zinc alloy, doped with yttrium and praseodymium // Uzbek chemical journal. -2022. – Nr3. - Pp.9-14.

Received: 03.05.2022; Accepted: 13.05.2022; Published: 30.06.2022

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INORGANIC CHEMISTRY

UDK 541.344

¹J. Sh. Bobojonov, ¹J. S. Shukurov, ¹A. S. Togasharov, ²N. K. Olimov

STUDYING THE SOLUBILITY OF THE SYSTEM СН₃СООН–NH₃– H₂O

¹Institute of General and Inorganic Chemistry of AS RUz,, Uzbekistan, 100170 Tashkent, М. Ulugbek, 77-а, Е-mail: jamshid_chem@mail.ru, ²Tashkent pharmaceutical institute, 100015 Tashkent, Oybek, 45

Abstract. Background. Physiologically active substances derived from carboxylic acids and their compounds are widely used in agriculture. Ammonium acetate has been proven to have nutritional and insecticidal properties. Taking into account the enhancement of the defoliating, nutritional and insecticidal properties of preparations, when ammonium acetate is added to them, the scientific justification for its preparation in a solution based on acetic acid and ammonia is relevant.

Purpose: physical and chemical substantiation of the process of obtaining ammonium acetate based on acetic acid and ammonia.

Methodology. We used visual-polythermal, pycnometric methods, the Kjeldahl method to find the concentration of ammonia. Viscosity was measured with a VPZh viscometer. pH–via pH meterFE20 METTLERTOLEDO, refractive index –by means of PAL-BX/RI refractometer.

Originality. For the first time, the physical and chemical foundations of the interaction of components in a system with the participation of water, acetic acid and ammonia have been created, and its polythermal solubility diagrams have been constructed. The "composition-properties" of the system [80%CH₃COOH + 20%H₂O] - [75% H₂O + 25% NH₃] were studied.

Findings. Based on the solubility polytherms of binary systems and internal sections, a polythermal solubility diagram of the CH₃COOH -NH₃ -H₂O system was constructed in the temperature range from -39.2 to 0˚С. On the polythermal solubility diagram, the fields of ice crystallization, CH₃COOH, CH₃COONH₄ and NH₃ are demarcated. The crystallization temperature, viscosity, density, pH, and refractive index of light in solutions of the system [80%CH₃COOH + 20%H₂O] - [75% H₂O + 25% NH₃] were determined depending on the ratio of components.

Key words: ammonium acetate, polytherm, binary system, IR spectrum, crystallization, medium pH.

Highlights:

- fields of crystallization of components in the system are revealed;

- freezing temperature of the CH₃COOH -NH₃ -H₂O system;

- constructed polythermal solubility diagram.

References

1. Trunin A.S., Petrova D.G. Visual-polythermal method. - Kuibyshev.: 1977.-C 94. Dep. in VINITI - No. 584-78. (in Russian)

2. A. Abdusamatov. ORGANIC CHEMISTRY. -Toshkent.: "Talqin", 2005.- 408 р. (in Russian)

3. Kirgintsev A.N., Trushnikova L.N., Lavrent'eva V.G. Solubility of inorganic substances in water. – L.: Chemistry, 1972.–248 р. (in Russian)

4. Khusanov E.S., Shukurov, Zh.S., Togasharov A.S. et al. Studying the solubility of components in the system H₃PO₄-CO(NH₂)₂ - NH₂C₂H₄OH - H₂O //Comp. mat. Uz. scientific those. Prod. zhur. –2021.–No. 4. –P. 3. (in Russian)

5. Khamdamova Sh.Sh., Tukhtaev S. Solubility in system calcium chlorate – diethanolamine – water // Aust. J. of Tech. and Nat. Sc. – Vienna.–2016. -Number 3. 4. -P. 147.

6. Shukurov Zh.S. Solubility polytherm of the system acetic acid - diethanolamine - water.//Uzb. chem. journal, -2008.-No3. -P.50. (in Russian)

7. Sidikova A.A., Toghasharova A.S., Shukurova J.S. Solubility and Rheological Properties of the System NaClO₃⋅CO(NH₂)₂–H₂SO₄⋅N(C₂H₄OH)₃–H₂O.//Russ. J. Inorg. Chem.–2021. –Vol. 66. –No.10. -P. 1554. (in Russian)

8. Khamdamova Sh.Sh., Kucharov Kh., Tukhtaev S. Solubility polytherm of the sodium chlorate–triethanolamine–water system.// Uzb. chem. zhur. -2003. -No. 5. -P. 29. (in Russian)

9. Rajaeian S.O., Ehsanpour A.A. Physiological responses of tobacco plants (Nicotiana rustica) pretreated with ethanolamine to salt stress.//Russ. J. Plant Physiol. –2015. -V.62. -P. 246. (in Russian)

10. ShukurovZh.S., Khusanov E.S., Mukhitdinova M.S. et al. Component Solubilities in the Acetic Acid–Monoethanolamine–Water System.//Russ. J. Inorg. Chem. -2021. -V.66.-P. 902. (in Russian)

11. Khusanov E. S., Shukurov Zh. S., Togasharov A. S. et al. Solubility of components in an aqueous system of triethanolamine urea phosphate. //Uzb. chem. jur.-2021. –N.2. –P.18-25. (in Russian)

12. Abdullaeva M.T., Ismailov D.U. Study of the mutual influence of components in the formic acid–monoethanolamine–water system. // Universum: technical sciences: electron. scientific magazine -2020. – No. 6 (75).

13. http://rupest.ru/ppdb/ammonium-acetate.html

14. Bazhenova LN Quantitative elemental analysis of organic compounds. Yekaterinburg: 2008. -356 p. (in Russian)

To cite this article: J. Sh. Bobojonov, J. S. Shukurov, A. S. Togasharov, N. K. Olimov. Studying the solubility of the system СН₃СООН–NH₃– H₂O // Uzbek chemical journal. -2022. – Nr3. - Pp.15-20.

Received: 23.02.2022; Accepted: 20.04.2022; Published: 30.06.2022

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UDK 661.185

M. B. Mavlyanov, M. Sh. Adilova, A. U. Erkaev

STUDYING THE INFLUENCE OF TECHNOLOGICAL PARAMETERS ON THE PROCESS OF POTASSIUM CHLORIDE CRYSTALLIZATION

Tashkent institutе of chemical technology

Abstract. Background. The increased content of low-grade sylvinite leads to a low indicator of product quality and the recovery factor of the main component - potassium chloride. In this regard, the problem of processing low-grade sylvinite from the Tyubegatanskoye deposit is relevant for the potash enterprise.

Purpose. The aim of the study is to study the influence of technological parameters on the process of crystallization of potassium chloride and to determine the optimal conditions for obtaining potassium chloride by the halurgical method of enrichment of low-grade sylvinite of the Tyubegatanskoye deposit.

Methodology. The solubility of low-grade sylvinite in water has been studied. When performing the work, standard methods of chemical analysis were used. The identification of solid phases was carried out by the method of physicochemical analysis.

Originality. For the first time, the influence of time, the ratio of low-grade sylvinite to water, temperature and cooling rate on the crystallization of potassium chloride was studied, and the rheological properties of suspensions obtained by dissolving low-grade sylvinite in water were studied.

Findings. Chemical and X-ray phase analyzes established the composition of the initial components and products of potassium chloride obtained by dissolving low-grade sylvinite in water.

Key words: solubility, ratio of solid and liquid phases, suspension, temperature, time, crystallization, low-grade sylvinite, water.

Highlights:

- the dissolution of low-grade sylvinite in water was studied,

- the optimal conditions for the crystallization of potassium chloride;

- the chemical and fractional composition of the obtained products;

-the rheological properties of the suspensions obtained during the experiments.

References

1. Isaeva G.A., Moloshtanova N.E., Maleev E.E. Influence of paleotectonics on the structure and material composition of potassium salts of the Upper Jurassic formation of the Central Asian basin (on the example of the Tyubegatanskoye deposit) // Bulletin of the Perm University. Geology. -2016.- Issue. 3 (32).- P. 6-20. (in Russian)

2. Ibragimov G.I., Erkaev A.U., Yakubov R.Ya., Turobjonov S.M. Potassium chloride technology. - T.; 2010. - 200 p. (in Russian)

3. Turko M. R., Shakhnazarov A. A., Vishnyak B. A. The main trends in the creation of technological schemes for processing sylvinite ores at the present stage // Mine of the future.-2010.-№ 4.-S. 90–98. (in Russian)

4. Processing of natural salts and brines: a reference book / I.D. Sokolov. - St. Petersburg: Chemistry, 2007. -208 p. (in Russian)

5. Methods of chemical analysis: textbook. allowance / O. N. Bulgakova. - Kemerovo: Kemerovo State University, 2015. - 146 p. (in Russian)

6. Analytical chemistry (analytics). Book 2. Quantitative analysis. Physico-chemical (instrumental) methods of analysis: / Yu. Ya. Kharitonov. - St. Petersburg: Higher School, 2001. - 560 p. (in Russian)

7. Pozin M.E. Guide to practical exercises on the technology of inorganic substances. - L.: Chemistry, 1980. - 368 p. (in Russian)

8. Zhukov A.F., Kolosova I.F., Kuznetsov V.V. Analytical chemistry. Physical and physico-chemical methods of analysis. -M.: Chemistry, 2001. -496 p. (in Russian)

9. Flame photometry: guidelines for laboratory work.// Samara. SGTU.-2013. -13 p. (in Russian)

10. Makoto Otsuka and Hajime Kinoshita. Quantitative Determination of Hydrate Content of Theophylline Powder by Chemometric X-ray Powder Diffraction Analysis. // AAPS Pharm Sci. Tech.-2010 March: 11(1).-204–211.

11. Ann Newman, Ph.D. X-ray Powder Diffraction in Solid Form Screening and Selection. September 1, 2011

To cite this article: M. B. Mavlyanov, M. Sh. Adilova, A. U. Erkaev. Studying the influence of technological parameters on the process of potassium chloride crystallization // Uzbek chemical journal. -2022. – Nr3. - Pp.20-27.

Received: 11.04.2022; Accepted: 29.04.2022; Published: 30.06.2022

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UDK 628.349.094.3

¹Zh. Kh. Kurbanov, ¹V. P. Guro, ²O. A. Mamazhanov, ¹M. A. Ibragimova, ¹Kh. F. Adinaev

METHOD FOR WATER PURIFICATION FROM ORGANIC IMPURITIES

¹Institute of General and Inorganic Chemistry of AS RUz,, Uzbekistan, ²Fergana polytechnic institute

Abstract. Background. Increasing attention, due to the growing shortage of fresh water, is being paid to the purification of industrial wastewater from organic (phenol, naphthenes, amines, etc.) impurities.

Purpose: Development of a method for treating wastewater from the Mubarek GPP from organic impurities for use in irrigated agriculture.

Methodology. A laboratory non-diaphragm electrolyzer, ИВС-1 direct current source, and ПИ-50-1 potentiostat were used. The presence of organic compounds in water was assessed by permanganatometry ГОСТ Р 55684-2013 (ISO 8467:1993) "Permanganate_oxidability".

Originality. Data are given on the rate of chemical and electrochemical interaction of organic compounds in water on the anode and cathode surfaces in a flow-through non-diaphragm electrolyzer.

Findings. The kinetic regularities of reactions of anodic and cathodic interaction of organic impurities in waste water of the Mubarek gas processing plant are revealed.

Key words: organic impurities, gas processing plant, wastewater, direct current source, electrodes, electrolysis.

Highlights:

- data on the composition of wastewater from a gas processing plant;

- a method of electrolysis water purification from organic impurities.

References

1. A. Baeshov, A.E. Konurbaev, N.S. Ivanov, T. Gaipov. The use of lumpy electrodes for wastewater treatment from organic compounds.// Bulletin of KazNU. Series chemical.- N 4 (64).-2011. - P.27-31.

2. Patent RU 2 129 529 C1. Water purification method and device for its implementation. Application 9710294 0/025. Publication date: 04/27/1999, applicant: Vadim Petrovich Kokin, Inventor: V. Kokin (in Russian)

3. Patent RU 2162822 C1, Method for purification of phenol-containing waters. Application: 99124525/12, 11/18/1999 (24) Start date of the patent: 11/18/1999 (46) Published: 02/10/2001. Applicant(s): Dagestan State University Author(s): Kaimarazova F.G., Aliev Z.M. (in Russian)

4. Patent RU 2094381 - apparatus for electrochemical water treatment. Author(s): Anokhin P.M., Gagarin E.N., Emelyanov G.I., Kalashnikov V.S. Patentee(s): Ecological Dzerzhinsk Association "EKODAS". Priorities: Applying: 1995-11-16; patent publication: 10/27/1997 (in Russian)

5. Guro V.P., Ibragimova M.A., Yusupov F.M., Shamsiev Sh.J., Adinaev H.F., Abdikamalova A.B. Development of technology for electrolysis water treatment of Mubarek GPP LLC from hydrogen sulfide// Uzbek. chem. and. -2021.-N3. - P. 3-10. (in Russian)

6. Application for a Patent UZ (Utility model) "Method of water purification from sulfides" No. FAP 2021 0343 dated 04.11.2021, authors: Guro V.P., Yusupov F.M., Yodgorov N.I., Shamsiev Sh .J., Ibragimova M.A., Yusupov S.K., Kurbanov Zh.Kh. (in Russian)

7. Kurbanov Zh.Kh., Guro V.P., Yusupov F.M., Shamsiev Sh.J., Ibragimova M.A., Adinaev Kh.F. Wastewater treatment of Mubarek Gas Processing Plant LLC from sulfide and organic compounds. // Uzbek. chem. and. 2022, No. 2. - P. 21-27. (in Russian)

8. Patent RU 178983 (13) U1 (Utility model). Device for wastewater treatment from multicomponent pollution. Ignatkina D.O.(RU), Voytyuk A.A. (RU), Moskvicheva A.V. (RU) and others. Appl. 11/13/2017; Published 04/24/2018. Bull. No. 12. (in Russian)

9. Patent RU 2033391. A method of wastewater treatment from organic impurities and a device for its implementation. Authors Bozina N.A., Vorozheikin A.P., Galukhin V.A., Dudalova T.V., Liakumovich A.G., Sosnovskaya L.B., Uryadov V.G., Filimonov V.A. Patentee Nizhnekamsk Production Association "Nizhnekamsk-Neftekhim" Registration. Application date: 07/15/1991 Publication date 04/20/1995. (in Russian)

10. Application for a UZ Patent (Utility Model) “Method of Water Purification from Organic Impurities”, No. FAP 2022 0137 dated April 22, 2022, authors: Guro V.P., Yusupov F.M., Shamsiev Sh.J., Kurbanov Zh. Kh. (in Russian)

To cite this article: Zh. Kh. Kurbanov, V. P. Guro, O. A. Mamazhanov, M. A. Ibragimova, Kh. F. Adinaev. Method for water purification from organic impurities // Uzbek chemical journal. -2022. – Nr3. - Pp.28-33.

Received: 25.04.2022; Accepted: 12.05.2022; Published: 30.06.2022

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UDK 541.123.3

¹J. S. Shukurov, ²B. B. Akhmedov, ²A. O. Nasrullaev

STUDY OF THE POLYTHERMIC SOLUBILITY OF THE H₂C₂O₄ 2H₂O - CO(NH₂)₂ - H₂O SYSTEM

¹Institute of General and Inorganic Chemistry of AS RUz,, Uzbekistan, ²Samarqand State University E-mail: axmedov.baxtiyor.1010226@gmail.com

Abstract. Background. Agriculture is considered not only from the position of providing food products, but also as a promising source of strengthening the export potential of the republic. With the reduction of areas under cotton and grain, mineral fertilizers, stimulants, defoliants and other plant protection products are required.

Purpose: substantiation of obtaining drugs with nutritional and physiologically active properties by studying the interaction and rheological properties of the systems of dihydrate oxalic acid and urea

Methodology. The solubility was determined using a viscometer VPZh, pH - on a FE 20 METTLER TOLEDO pH meter, light refractive index - on a PAL-BX/RI refractometer.

Originality. The interaction of two-water oxalic acid and urea was studied, and on their basis a diagram of the solubility of systems and "composition-properties" was constructed.

Findings. Based on two-component systems and internal sections, a polythermal solubility diagram for the systems H₂C₂O₄·2H₂O - CО(NH₂)₂ - H₂Owas constructed in the temperature range from -11.2 to 92°C. The limits of crystallization of ice, dihydrate oxalic acid, carbamide and a new phase of carbamide oxalate were determined, and the composition was identified. The crystallization temperatures, viscosity, density and pH were established depending on the ratio of components when urea was added to oxalic acid.

Key words: solubility, system, diagram, "composition-properties", crystallization temperature, viscosity, density.

Highlights:

- interaction of components of water, two-water oxalic acid and urea;

- the rheological properties of the solution were determined by the interaction of the components.

References

1. Zh.S. Shukurov, S.S. Ishankhodzhaev, M.K. Askarova, S. Tukhtaev. Study of the solubility of components in the NaClO₃⋅2CO(NH₂)₂-NH₂C₂H₄OH⋅CH₃COOH–H₂O system // Russian Journal of Inorganic Chemistry. -2011. -Vol. -56. -No. 3. P. 463–466. (in Russian)

2. E.S. Khusanov, Zh.S. Shukurov, A.S. Togasharov, S. Tukhtaev. H₃PO₄•CO(NH₂)₂ - NH₂C₂H₄OH - H₂O studying the solubility of components in the system // Scientific-technical and practical journal of composite materials. - Tashkent.. – 2021. -No4. - P. 3-5. (in Russian)

3. Togasharov A.S., Askarova M.K., Tukhtaev S. Solubility polytherm of Ca(ClO₃)₂-NH₂C₂H₄OH HNO₃-H₂O system // Reports of the Academy of Sciences. - Tashkent. - 2015. - No. 6. - P. 50-53. (in Russian)

4. Tsyplenkova A.Yu., Koltsova O.V., Lobanov N.N. and others // Bottle. message.-2013.-T. 36.- No. 11. -S. 146. https://roi:jbc-01/13-36-11-146. (in Russian)

5. Fadeeva V.P., Tikhova V.D. Quantitative elemental analysis of organic substances and materials. –Novosibirsk. 2013. - 128 p. (in Russian)

6. Shukurov J. S., Askarova M.K., Tukhtaev S. The solubility of components in the system NaC-lO₃•CO(NH₂)₂-C₂H₅OH-H₂O // Austrian Journal of Technical and Natural Sciences. –Austria. -2017. -No7-8. -P. 69-72.

7. Yousef A. Mubarak. Production of Crystalline Urea Phosphate using the Untreated Jordanian et Process Phosphoric Acid // Department of Chemical Engineering, University of Jordan. Engineering Sciences. -2011. –Vol.38.-No. 1.–P. 61-72.

8. Togasharov A.S., Shukurov Zh.S., Tukhtaev S. et al.// New defoliants based on chlorates and industrial waste of cotton ginning plants.// T.-Navruz.- 2019. (in Russian)

9. Z.Kh. Adilov. Solubility in the system CO(NH₂)₂ - C₁₀H₁₁ClN₄ - H₂O.//Uzbek chemical journal.-2008. -No. 3.- P.25-28. (in Russian)

10. Trunin A.S. Petrova D.G. Visual - polythermal method / Kuibyshev Polytechnic. Inst. - Kuibyshev, -1977. - 94 p. Dep. in VINITI No. 584-78. (in Russian)

11. Bazhenova L.N. Quantitative elemental analysis of organic compounds. – Yekaterinburg, 2008. – 356 p. (in Russian)

12. Apelblat A., Manzurola E. Solubility of Oxalic, Malonic, Succinic, Adipic, Maleic, Malic, Citric, and Tartaric Acids in Water from 278.15 to 338.15 K. // J. Chem. Thermodynamics 19: (1987) 3, p. 317–320.

13. Department of Biochemical and Chemical Engineering Laboratory of thermodynamics Prof. Dr. Gabriele Sadowski Oxalic Acid – Phase Behavior of a Cocrystal and Hydrate Forming Component .Master-thesis Dortmund, March 29, 2016.

To cite this article: J. S. Shukurov, B. B. Akhmedov, A. O. Nasrullaev. Study of the polythermic solubility of the H₂C₂O₄ 2H₂O - CO(NH₂)₂ - H₂O system // Uzbek chemical journal. -2022. – Nr3. - Pp.33-38.

Received: 02.06.2022; Accepted: 22.06.2022; Published: 30.06.2022

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UDK 541.183.6:661.185.1

R. R. Makhkamov, A. E. Kurbanbayeva, Sh. K. Samandarov, M. L. Nurmanova, F. R. Saidkulov

STUDY OF THE PROPERTIES AND EFFICIENCY OF NEW SURFACTANTS FOR THE REGULATION OF STRUCTURE FORMATION IN CEMENT SLURRIES

Institute of General and Inorganic Chemistry of AS RUz e-mail: ravshanmak@gmail.com

Abstract. Background. Surface-active agents (surfactants) are widely used to improve the quality of materials and control technological processes. The urgent problem is the creation of new surfactants and their compositions that improve the rheological and structure-forming properties of dispersed systems and cement slurries.

Purpose. Obtaining new surface-active derivatives of maleic acid, the study of their colloid-chemical properties and effectiveness for regulating structure formation in cement suspensions.

Methodology. Measurements for the study of plastic strength and structure formation of cement mixtures were carried out on a Geppler consistometer. The density of the cement mixture was characterized by the ratio of the mass of the compacted mixture to its volume. The hydrophilic-lipophilic balance of new surfactants was calculated by group numbers. A refractometer was used to determine the refractive index of aqueous solutions of surfactants. The surface tension of surfactant solutions was determined by Rebinder device.

Originality. New surfactants based on maleic acid derivatives with different numbers of ethoxy groups and carbon atoms in the alkyl chain have been obtained. It has been established that they are effective regulators of the structure formation of cement dispersed systems.

Findings. It has been established that with an increase in the number of ethoxy groups in the molecule and the length of the carbohydrate chain, the surface activity and foaming ability of surfactants of maleic acid derivatives increase.

Key words: Surfactants, surface activity, structure formation regulators, plasticizing effect, cement dispersed systems.

Highlights:

- new surfactant derivatives of maleic acid;

- they regulate structure formation in cement dispersed systems;

- surfactants in combination with marble powder enhances plasticizing effect.

References

1. Eric B., Joel F., Grace O. Oil Well Cement Additives: A Review of the Common Types// J. Oil and Gas Research.-2016. -V 2, Issue 2.-P.1-6.

2. Feneuil B., Pitois O., Roussel N. Effect of surfactants on the yield stress of cement paste// Cement and Concrete Research. -2017.-V 100.-P. 32–39.

3. MichauxM., NelsonE., VidickB.Cement chemistry and additives//J.well completion. -2019.-V1.-N1. –P.18-25.

4. Kronberg B., Holmberg K., Lindman B. Types of surfactants, their synthesis, and applications.// Surface Chemistry of Surfactants and Polymers.- Wiley, Hoboken.-NJ, USA.-2014.

5. BazhenovYu.M. Concrete technology: textbook, manual for technologist, building specialties.// Universities - 3rd ed. –M. - 2011. -500 p.

6. NegimE., RamliM., SaadB., BekbayevaL., SalehM., Effects of surfactants on the properties of styrene/methacrylate-type superplasticizer in cement paste// Polymer-Plastics Technology and Engineering. -2011. -V 50.-N 9.-P.941–946.

7. Yoshioka K., Tazawa E., Kawai K., Enohata T. Adsorption characteristics of superplasticizers on cement component minerals// Cement and Concrete Research. – 2002.-V 32(10).-P1507–1513.

8. SargamY., WangK., TsyrenovaA., LiuF., JiangS. Effects of anionic and nonionic surfactants on the dispersion and stability of nanoSiO2 in aqueous and cement pore solutions// Cement and Concrete Research. -2021. -V144.-P. 106-116.

9. FerrariL., KaufmannJ., WinnefeldF., PlankJ. Interaction of cement model systems with superplasticizers investigated by atomic force microscopy, zeta potential, and adsorption measurements// Journal of Colloid and Interface Science.-2010. -V 347.-N 1. –P. 15–24.

10. GueitE., Darque-CerettiE., TintillierP., Horgnies M.Influence of surfactants on cement hydration at the concrete / formwork interface. International RILEM Conference on Use of Superabsorbent Polymers and Other New Additives in Concrete, Lyngby, Denmark.-2010.

11. KnapenE., Van GemertD. Cement hydration and microstructure formation in the presence of water-soluble polymers// Cement and Concrete Research. -2009. -V 39.-N. 1.-P. 6–13.

12. FanW., StoffelbachF., RiegerJ., A new class of organosilane-modified polycarboxylate superplasticizers with low sulfate sensitivity// Cement and Concrete Research.-2012.-V 42.-N. 1.-P. 166–172.

13. TianY., JinX., JinN., ZhaoR., LiZ., MaH., Research on the microstructure formation of polyacrylate latex modified mortars// Construction and Building Materials.-2013. –V. 47.-P 1381–1394.

14. BazhenovYu.M., DemyanovaB.C., Kalashnikov V.I. Modified high-quality concretes - M.: Publishing house of the Association of building universities, 2006. - 368 p.

15. NegimE., KhatibJ., InkarbekovN. Effect of acrylate copolymers on the rheological properties of portland cement mortar pastes// World Applied Sciences Journal.-2013.-V. 23.-N 4.-P. 549–553.

16. Tunstall L., Scherer G., Prudhomme R. Studying AEA interaction in cement systems using tensiometry// Cement and Concrete Research.-2017.-V. 92.-P. 29–36.

17. BazhenovYu.M., Alimov V.V. Voronin et al. Technology of concrete, building products and structures -M.: Publishing house ASV, 2008. - 350 p.

To cite this article: R. R. Makhkamov, A. E. Kurbanbayeva, Sh. K. Samandarov, M. L. Nurmanova, F. R. Saidkulov. Study of the properties and efficiency of new surfactants for the regulation of structure formation in cement slurries // Uzbek chemical journal. -2022. – Nr3. - Pp.38-45.

Received: 30.03.2022; Accepted: 29.04.2022; Published: 30.06.2022

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UDK 666.762.2/553.546

A.A. Eminov

INFLUENCE OF THE CLAY COMPONENT ON THE THERMOMECHANICAL PROPERTIES OF THE REFRACTORY MASS

Institute of General and Inorganic Chemistry of AS RUz,, Uzbekistan, 100170 Tashkent, М. Ulugbek, 77-а, E-mail: azizeminov85@mail.ru

Abstract. Background. The production of silicate and refractory materials, in particular, refractory products, based on mineral raw materials and industrial waste is given increased attention, which is of national economic importance for the economy and solving environmental problems.

Purpose. Investigation of the influence of the clay component on the thermomechanical characteristics of a high-silica refractory material based on the "quartzite-clay" composition.

Methodology. Laboratory experimental work was carried out using modern physical-chemical and physical-mechanical research methods.

Originality. The optimal ratios of the added clay component in the double composition "quartzite-clay" and the thermomechanical properties of the obtained quartz-clay refractory mass during their high-temperature processing have been established.

Findings. The influence of the added clay component on the thermomechanical properties, in particular, on the change in linear dimensions, mechanical strength and refractoriness of the high-silica refractory mass, has been determined. The optimal amount of added clay in quartzite mixtures has been established, which is 25 wt %,

Key words: quartzite, clay, temperature, physical and mechanical, shrinkage, strength, refractoriness, double composition, heat treatment.

Highlights:

- the optimal ratio of clay to quartzite mixture is 25 wt. %;

- shrinkage occurs, and above 25 wt. % expansion of samples is observed;

- polymorphic transition of low-temperature silica to high-temperature forms

References

1. Papko L.F., Pavlyukevich Yu.G. Refractories for glass melting furnaces. Minsk: BSTU, 2008. - 100 p. (in Russian)

2. Kainarsky I.S. Dinas: Theoretical foundations, property technology and service. -M: Ed. "Literature on ferrous and non-ferrous metallurgy", 1961.- 469 p. (in Russian)

3. Strelov K.K., Kashcheev I.D. Refractories technology.-M: Ed. "Metallurgy", 1988.- 528 p. (in Russian)

4. Chemical technology of ceramics and refractories. Edited by Budnikov P.P., Poluboyarinov D.N.-M: - Izd.Stroyizdat, 1972.- 552p. (in Russian)

5. Volochko A.T., Dyatlova E.M., Podbolotov K.B. Refractory and refractory ceramic materials.-Minsk: Izd. "Belarusian Science", 2014.- 387p. (in Russian)

6. Dyatlova E.M., Klimosh Yu.A. Chemical technology of ceramics and refractories. V.2, Part 1.//Chemical technology of inorganic substances, materials and products.-Minsk, BSTU.- 2014.-224p. (in Russian)

7. Eminov, A.A., Abdullaeva, R.I., Kadyrova, Z.R. Dzherdanakskoe Quartz Rock for Ceramic and Refractory Materials Production.// Glass and Ceramics.- 2017.-Vol.74:Issue 1-2.-R.64–66.

8. Sabirov B.T., Kadyrova Z.R., Tairov S.S. Development of Optimal Compositions of Ceramic Tiles Using Dune Sand.// Glass and Ceramics.-2019.-75. Issue 9-10.-R.363-365.

9. Eminov A.A., Abdullaeva R.I., Kadyrova, Z.R. Development of composition of dinas refractory mass based on local resources of Uzbekistan//Journal of Chemical technology and Metallurgy.- Bulgaria, Sofia.- 2017.-Vol.52.- No.1.-P.93-97.

10. Eminov A.A. Properties of dinas ramming masses depending on charge compositions.// Refractories and technical ceramics.- 2014.-No9.-p.43-46. (in Russian)

11. Eminov A.A., Namazov Sh.S., Kadyrova Z.R. Sintering processes and solid-state reactions in the triple composition "quartzite-clay-additives".//Glass and ceramics.-2022.-No5.-p.38-44. (in Russian)

12. Kadyrova Z.R., Bugaenko V.A., Eminov A.A., Sabirov B.T. Study of raw materials and industrial waste of Uzbekistan for the production of refractory materials // Refractories and technical ceramics, 2010.-No4.-P.64-67. (in Russian)

13. Lach V. Einflus von Mineralisatoren auf lie Umwaldung von Quarzen.//Sprechsaal.-1990.- Volume 123.- No. 8.- P.811-813.

14. Karklit A.K., Larin A.P., Losev S.A., Bernikovsky B.E. Production of refractories in a semi-dry way.-M.: Metallurgy, 1981.-320 p. (in Russian)

15. Allenstein J. et al. Refractory materials. Structure, properties, tests. Directory. / ed. G. Rouchka, H. Butnau/, trans. from German-M: Intermet Engineering, 2010.- 392 p. (in Russian)

To cite this article: A.A. Eminov. Influence of the clay component on the thermomechanical properties of the refractory mass // Uzbek chemical journal. -2022. – Nr3. - Pp.46-51.

Received: 07.04.2022; Accepted: 23.05.2022; Published: 30.06.2022

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UDK 631.87

O. V. Myachina, R. N. Kim, L. E. Mamasalieva, S. A. Burieva, P. Kh. Ganiev, A. Kh. Rakhmonov, B. A. Pulatov, O. S. Narzullaev

IMPACT OF HUMIC FERTILIZERS ON THE MICROBIAL POTENTIAL OF SERIOZEM SOIL UNDER COTTON CROPS

Institute of General and Inorganic Chemistry of AS RUz

Abstract. Background. Soil organic matter is a key factor in soil fertility. Providing agriculture with them is of decisive importance for the development of the industry. A promising direction in the development of the production of organic fertilizers is the technology of processing brown coal and their waste.

Purpose: to determine the impact of humic fertilizers from processed Angren brown coal on the dynamics of microbial communities of irrigated typical serozem during the growing season of cotton.

Methodology: In a two-factor experiment, the number of soil microorganisms of the main ecological and trophic groups and their ratio were studied; statistical and correlation analysis - using "STATISTICA 10.0" and "Excel" data package.

Originality: For the first time, the effect of humic fertilizers on the number of microorganisms of physiological and ecological-trophic groups that transform nutrients in the soil has been established, factorial and variance analysis confirmed the relationship between biological and agrochemical characteristics of the soil.

Findings: It has been established that the use of nitrogen and phosphorus humic fertilizers, based on oxidized brown coal, transforms soil microbial complexes. Humic fertilizers reduce the intensity of mineralization processes, increasing the utilization factor of nutrients.

Key words: humic fertilizers, phosphorus, nitrogen, microorganisms, activity, gray soil, cotton.

Highlights:

- influence of humic compounds on soil microbial communities;

- correlation of the number of microorganisms with the agrochemical properties of the soil;

References

1. Methods of soil microbiology and biochemistry. Tutorial. Zvyagintsev D. G. (ed.) - M .: MGU, 1991. - 304 p. (in Russian)

2. Bab'eva I. I., Zenova G. M. Biology of soils. - M: MGU, 1989. -336 p. (in Russian)

3. WRB, 2006: World reference base for soil resources. A framework for international classification, correlation and communication.// Food and Agriculture Organization of the United Nations.- Rome. -2006.- 145 p.

4. Methods of agrochemical analyzes of soils and plants of Central Asia.-Tashkent: SoyuzNI-HI, 1977. -176 p. (in Russian)

5. R Core Team. R: A language and environment for Statistical Computing; R Foundation for Statistical Computing: Vienna, Austria, 2017; Available online: https://www.R-project.org (accessed on 6 October 2018).

6. Microbial biotechnologies: fundamental and applied aspects.// Collection of scientific papers.- V. 10.- 506 p. (in Russian)

7. Sviridova O.V. Microbiological processes of humus transformation in soddy podzolic soil with the use of nitrogen fertilizers: Abstract of the thesis. diss...cand. biol. Sciences. St. Petersburg: VNII agricultural. Microbiology, 1992.- P. 16. (in Russian)

8. Devyatova T.A., Bezler N.B., Antonyuk A.N. Influence of agricultural land and soil subtype on the microbial community of zonal soils on the example of chernozems of the stone steppe. Vestnik VGU. Series chemistry, biology, pharmacy.- 2003.- No. 1.-P.46-49. (in Russian)

9. Shemelinina T.N. Biological activity of oil-contaminated soils of the Far North at different stages of their restoration and recultivation (on the example of the Usinsk region of the Komi Republic): Author's abstract ... cand. biol. Sciences.- Voronezh.-2008.-P. 24. (in Russian)

10. Sukhovitskaya L.A., Veremeychik L.A., Safronova G.V., Korolenok N.V., Lantsevich A.A. Changes in the content and qualitative composition of microorganisms in mineral substrates used for growing tomatoes. // News of the National Academy of Sciences of Belarus. Agrochemistry.-2006.- No2.- P.73-77. (in Russian)

11. Dymova L.V., Nesterova L.B. The relationship between the number of microorganisms and mineral forms of nitrogen in the soil. // Agrochemical Bulletin.-2006.-No4.- P.18. (in Russian)

12. Selyanin V.V., Oborotov G.E., Zenova G.M., Zvyaguntsev D.G. Alkaliphilic soil actinomycetes, Microbiol. Journal.-Vol. 74.- No. 6.-2005. -P. 729-734.

13. Blagoveshchenskaya G.G., Dukhanina T.M. Microbial communities of soils and their functioning under conditions of application of chemicals. // Agrochemistry. -2004.- No. 2.- P. 80-88. (in Russian)

14. Medvedeva M.V., Moshkina E.V. Peculiarities of the nitrogen regime and microbial transformation in soils of natural and anthropogenically disturbed biogeocenoses, Tr. International Forum on the problems of science, technology and education.-V.3.- M.: Academy of Earth Sciences, 2004.-P. 42-45. (in Russian)

To cite this article: O. V. Myachina, R. N. Kim, L. E. Mamasalieva, S. A. Burieva, P. Kh. Ganiev, A. Kh. Rakhmonov, B. A. Pulatov, O. S. Narzullaev. Impact of humic fertilizers on the microbial potential of seriozem soil under cotton crops // Uzbek chemical journal. -2022. – Nr3. - Pp.52-60.

Received: 21.06.2022; Accepted: 29.06.2022; Published: 30.06.2022

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ORGANIC CHEMISTRY

UDK 577.114.4

O. R. Akhmedov, Sh. A. Shomurotov, J. A. Abdurakhmanov, J. A. Khabibullaev, A. S. Turaev

STUDY OF THE CHEMICAL REDUCTION OF AZOMETHINE DERIVATIVES OF POLYALDEHYPECTIN WITH GUANIDINE

Institute of Bioorganic Chemistry of AS RUz, M.Ulugbek 83, Tashkent, 100125, e-mail: ibchem@uzsci.net

Abstract. Background. The development of methods for the synthesis and study of polymeric derivatives of guanidine are priority areas in the chemistry of macromolecular compounds. Polymer compounds containing guanidine groups have unique pharmacological properties. Due to the structural features and reactivity, guanidine undergoes modification, which allows it to be fixed into polysaccharide macromolecules.

Purpose. Synthesis and determination of the features of the chemical reduction of azomethine bonds of guanidium-containing pectin derivatives.

Methodology. Chemical modification of guanidine with polyaldehyde pectin was carried out. The synthesized compounds were studied by IR spectroscopy, elemental, functional titrimetric analysis. The conditions for the chemical transformation of azomethine bonds of guanidine-containing pectin derivatives into amine bonds have been studied.

Originality. The optimal reaction conditions for the chemical reduction of azomethine bonds of guanidine-containing pectin derivatives have been synthesized and found.

Findings. Azomethine derivatives have been synthesized based on the reaction of nucleophilic substitution of reactive aldehyde groups of oxidized pectin with guanidine. The conditions for the chemical transformation of azomethine bonds of guanidine-containing pectin derivatives into strong amine bonds by chemical reduction are found.

Key words: guanidine, pectin, polyaldehyde pectin, azomethine bond, chemical reduction, hydrolysis

Highlights:

- method of chemical modification of guanidine with pectin carbonyl derivatives;

- reaction conditions for the reduction of azomethine bonds of guanidine-containing pectin derivatives.

References

1. Kukharenko O., Bardeau J.-F., Zaets I., Ovcharenko L., Tarasyuk O., Porhyn S., Kozyrovska N. Promising low cost antimicrobial composite material based on bacterial cellulose and polyhexamethylene guanidine hydrochloride // European Polymer Journal. -2014.-V.60.-P.247-254.

2. Qian L., Guan Y., He B., Xiao H. Modified guanidine polymers: Synthesis and antimicrobial mechanism revealed by AFM // Polymer.-2008.-V.49(10).-P.2471-2475.

3. Zhang Z., Peng P., Wu Q., Zhang J., Wu M., Liu J. Preparation and antibacterial properties of poly(hexamethylene guanidine hydrochloride) modified ionic waterborne polyurethane // Progress in Organic Coatings. -2021.-V.156.-P.106246.

4. Grigorieva M.N., Stelmakh S.A., Astakhova S.A., Center I.M., Bazaron L.U., Batoev V.B., Mognonov D.M. Synthesis of copolymers of polyalkylguanidine hydrochlorides and their antibacterial activity against opportunistic microorganisms Bacilluscereus and Escherichiacoli.//Chemical and pharmaceutical journal.-2015.-T.49.-No.2.-P.29-33. (in Russian)

5. Chen S., Li C., Hou T., Cai Y., Liang L., Chen L., Li M. Polyhexamethylene guanidine functionalized chitosan nano fiber membrane with superior adsorption and antibacterial performances // Reactive and Functional Polymers.-2019.- P.104379 .

6. Liu K., Xu Y., Lin X., Chen L., Huang L., Cao S., Li J. Synergistic effects of guanidine-grafted CMC on enhancing antimicrobial activity and dry strength of paper // Carbohydrate Polymers. -2014.-V.110.-P.382-387.

7. Naidenko E.V., Makarov S.V., Pokrovskaya E.A., Nikulin A.M. Modification of chitosan with thiourea dioxide // Chemistry and Chemical Technology.-2021.-T.64.- No. 1.-P.73-78. (in Russian)

8. Houben-Weil. Methods of organic chemistry.- Moscow, 1967.-T.2.-1032 p. (in Russian)

9. T. V. Tunik, U. M. Nemchenko, T. V. Ganenko, G. V. Yurinova, Yu. P. Dzhioev, B. G. Sukhov, V. I. Zlobin, and B. A. Trofimov, Synthesis and spectral characterization of new biodegradable arabinogalactan derivatives for diagnostics and therapy.// Izvestiya RAN. Physical series.-2019.-T.83(3).-P.408-414. (in Russian)

10. Syutkin V.N., Nikolaev A.G., Sazhin S.A., Popov V.M., Zamoryansky A.A. Nitrogen-containing derivatives of dialdehyde cellulose. 2. Synthesis of dialdehyde cellulose derivatives with nitrogenous heterocycles // Chemistry of vegetable raw materials. -2000. -No.1.-P.5-25. (in Russian)

11. Medusheva E.O., Filatov V.N., Ryltsev V.V., Belov A.A., Kulagina A.S. Dialdehydecellulose derivatives modified with biologically active substances // Pharmacy.-2016.-No.1.-P.52-56. (in Russian)

12. Akhmedov O.R., Shomurotov Sh.A., Turaev A.S. Features of the synthesis and antimicrobial properties of guanidine-containing derivatives of carboxymethylcellulose // Chemistry of vegetable raw materials.- 2021.-No3.-P.73-82. (in Russian)

13. Akhmedov O.R., Shomurotov Sh.A., Turaev A.S., Khabibullaev Zh.A. Design of biologically active cellulose derivatives containing guanidine groups // Uzbek chemical journal.-2020.-No4.- P.66-75. (in Russian)

14. Tishchenko E.V. Interaction of amino- and hydroxy(oxo) derivatives of heterocycles with polysaccharides - a new route for the synthesis of biologically active substances: Author's abstract ... cand. chem. Sciences. SPb., 2003.-26 p. (in Russian)

To cite this article: O. R. Akhmedov, Sh. A. Shomurotov, J. A. Abdurakhmanov, J. A. Khabibullaev, A. S. Turaev. Study of the chemical reduction of azomethine derivatives of polyaldehypectin with guanidine // Uzbek chemical journal. -2022. – Nr3. - Pp.61-68.

Received: 04.03.2022; Accepted: 07.05.2022; Published: 30.06.2022

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UDK 547.79:547;222-224

U. S. Makhmudov, A. A. Ziyaev, I. F. Tozhiev

STUDY OF THE CRYSTAL STRUCTURES OF 2-(ALKYLTHIO)-5-(PYRIDINE-2,3,4-YL)-1,3,4-OXADIAZOLES

¹Academy of Sciences of the Republic of Uzbekistan, ²Institute of Chemistry of Plant Substances of the Academy of Sciences of the Republic of Uzbekistan, 100170, Tashkent, М.Ulugbek, 77, e-mail: aziyaev05@rambler.ru

Abstract. Background. The combination of structural fragments of pyridine and 1,3,4-oxadiazole in one molecule can lead to the preparation of substances based on them with pharmacological activity.

Purpose: study of the crystal structures of 2-(alkylthio)-5-(pyridin-2,3,4-yl)-1,3,4-oxadiazoles.

Methodology. Single crystals of 2-(benzylthio)-5-(pyridin-4-yl)-1,3,4-oxadiazole, 1-(piperidin-1-yl)-2-((5-pyridin-3-yl)-1,3,4-oxadiazol-2-)thio)ethan-1-one and butyl ether of [5-(2-pyridyl)-1,3,4-oxadiazole-2-iltio] acetic acid were grown by evaporation at room temperature from a solution of a mixture of solvents ethanol and chloroform having the appearance of transparent elongated prisms.

Originality. Single crystals of molecules of 2-(alkylthio)-5-(pyridin-2,3,4-yl)-1,3,4-oxadiazoles were obtained for the first time and their structure was studied according to X-ray diffraction analysis (XRD).

Findings. The main crystallographic parameters in the crystal structures of 2-(alkylthio)-5-(pyridin-2,3,4-yl)-1,3,4-oxadiazoles 4-6 have been found.

Key words: X-ray diffraction analysis (XDR), 2-(alkylthio)-5-(pyridin-2,3,4-yl)-1,3,4-oxadiazoles, crystal structures.

Highlights:

- study of crystal structures of 2-(alkylthio)-5-(pyridin-2,3,4-yl)-1,3,4-oxadiazoles

References

1. Santosh K.V., Rameshwari V., Shekhar V., Yogesh V. Anti-tuberculosis activity and its structure activity relationship (SAR) studies of oxadiazole derivatives: A key review // European Journal of Medicinal Chemistry. -2021. -P. 209, 112886 https://doi.org/10.1016/j.ejmech.2020.112886

2. Rubina B., Dharam P.P., Garima K., Ravi K., Manni D. Recent Developments on Pharmacological Potential of 1,3,4-Oxadiazole Scaffold // Indian J of Pharmaceutical Education and Research. -2019. -Vol. 53.-2S. -P.1-16.

3. Kumar B., Kumar A., Beheraand A.K., Raj V. (2016) Latest Update on Pharmacological Activities of 1,3,4-Oxadiazole Derivatives. // J. Cell Sci Ther. -2016. -Vol.7. -#1. -R. 1-7.

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To cite this article: U. S. Makhmudov, A. A. Ziyaev, I. F. Tozhiev. Study of the crystal structures of 2-(alkylthio)-5-(pyridine-2,3,4-yl)-1,3,4-oxadiazoles // Uzbek chemical journal. -2022. – Nr3. - Pp.68-74.

Received: 07.06.2022; Accepted: 29.06.2022; Published: 30.06.2022

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UDK 66.074.51.069.833

A. M. Khurmamatov, A. U. Auesbaev

DENSITY DETERMINATION OF AMINE SOLVENTS FOR ACID GAS REMOVAL

Institute of General and Inorganic Chemistry of AS RUz, Tashkent, e-mail: alisherauesbaev@gmail.com

Abstract. Background. In the petrochemical industry, amine solutions are used. Their density when modeling mass transfer in absorbers and regenerators is important, as it affects the mass transfer coefficient.

Purpose. Determine the density of the amine solution at different mass ratios, in the range from 10°C to 140°C, propose the optimal function for calculating the density.

Methodology. Density was measured at temperatures from (0°C to 140°C). The aqueous mixture was prepared on a CAS NWP-3000 balance. A second-order polynomial temperature model was used for the calculation.

Originality.The optimal function and regression parameters are determined. The 40%MDEA/60% mixture was found to be more stable than the other mixtures in the range from 10°C to 140°C.

Findings.With an increase in temperature from 10°C to 70°C, the density of 50% MDEA/50% water decreased, and at 70°C it became equal to the density of a mixture of 30% MDEA/70% water. As the temperature rises from 70°C to 140°C, the 30%MDEA/70%water density curve changes like the 40%MDEA/60% density curve. At 140°C, the density value of the mixture 30%MDEA/70%water is close to 40%MDEA/60%. The density of the 40%MDEA/60% mixture, over the entire temperature range, is more stable than others.

Key words: N-methyldiethanolamine, MDEA, equations, density, regression parameters, model, mixture.

Highlights:

- density of pure MDEA and binary mixtures of MDEA + water at different ratios of MDEA.

- the optimal function for determining the density, dependent on temperature, is proposed.

- calculated regression parameters of pure MDEA and binary mixture of MDEA + water.

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To cite this article: A. M. Khurmamatov, A. U. Auesbaev. Density determination of amine solvents for acid gas removal // Uzbek chemical journal. -2022. – Nr3. - Pp.74-80.

Received: 16.06.2022; Accepted: 29.06.2022; Published: 30.06.2022