SPECTRAL FEATURES AND HYDROGEN BOND STRUCTURE OF AQUEOUS SOLUTIONS OF ETHANOL

The aim of this work is develop an approach that makes it possible to study the spectral properties and structure of intermolecular hydrogen bonds in aqueous solutions of ethanol formed in systems whose existence in a gaseous medium or an isolated state is practically impossible. This approach bases on the combined use of infrared spectroscopy and molecular dynamics (MD) methods. An analysis give the structural reorganization of water molecules depending on the concentration of ethanol alcohol. It has been shown that the method of molecular dynamics with classical force fields makes it possible to explicitly take into account the molecules of the solvent and solute, and, thus, to investigate hydrogen bonds in the system and to interpret with the experimental data obtained by vibrational spectroscopy.

FEATURES OF THE FORMATION OF THE COATING STRUCTURE ON TITANIUM-BASED ALLOYS

Previously shown that coatings formed on titanium by plasma electrolytic oxidation (PEO) in an electrolyte with zirconium sulfate Zr(SO4)2 consisted of ZrO2 and TiO2 oxides, their surface layer is enriched with zirconium, they have good protective properties in chlorine-containing media. The resulting layers have a fairly regular distribution of relatively small pores, with a diameter of about 1 μm or less, on the surface. The composition and structure of PEO layers depend on both the composition of the electrolyte and the modes of formation. It is of scientific and practical interest to elucidate the effect of the conditions for the formation of coatings with ZrO2 on titanium and its alloys on their anticorrosive properties in chlorine-containing media. Samples for research were formed under anodic (unipolar) conditions at the same current density and different formation times. The samples were formed in modes with current density 0.08 A/cm2 and processing time (minutes) − 8.5; 9.5; 10; 11; 12; 13; 14; 15; 20; 30; 40; 60. The duration of treatment was chosen as to maximally repeat the anticorrosive characteristics obtained in the previous case. The work uses modern research methods, including electron microscopy, presents the results of further study of ZrO2 + TiO2 / Ti systems formed in an electrolyte with zirconium sulfate Zr(SO4)2. It has been established that coatings are formed on titanium and its alloys in an electrolyte with zirconium sulfate under galvanostatic conditions of the PEO process at i = 0.08 A / cm2 during a processing time of 11-15 min. There is a correlation between the stages of galvanostatic formation of coatings and their anticorrosive properties.

SYNTHESIS AND SPECTROSCOPIC STUDY OF COMPLEX COMPOUNDS MN (II), CO (II), CU (II) AND ZN WITH 5-AMINO-2-MERCAPTOBENZIMIDAZOLE

The aim of this work is to study the effect of the nature of electron-donor and electron-withdrawing substituents in the molecules of heterocyclic ligands, the nature of acidoligands and transition metal ions on the properties of the synthesized coordination compounds. A method for the synthesis of new complex compounds of Mn (II), Cо (II), Cu (II) and Zn with 5-amino-2-mercaptobenzimidazole has been developed and the composition and structure of the synthesized complex compounds have been studied using modern physicochemical methods, such as elemental, thermogravimetric, X-ray phase analysis and IR spectroscopy. Coordination competing donor centers, electronic and geometric structures of the ligand molecule were studied using quantum-chemical calculations in the Gaussian09 LanL2DZ software package. It was shown that during the formation of a metal complex, the ligand 5-amino-2-mercaptobenzimidazole is coordinated through the localized nitrogen atom of the imidazole ring.

DETERMINATION OF THE STABILITY OF COMPLEX COMPOUNDS OF COPPER (II), ZINC (II), CADMIUM (II) AND SILVER (I) WITH COVALENTLY IMMOBILIZED SULFUR CONTAIN LIGANDS

"The purpose of this study is to determine the stability of the obtained coordination compounds of some d-metals with covalent immobilized sulfur-containing ligands. To achieve this goal, coordination compounds of copper (II), zinc (II), cadmium (II) and silver (I) ions with covalent immobilized sulfur-containing ligands - О,О-di- (2-aminoethyl) -dithiophosphate potassium - polyester matrix (KD2AEDTP-PEM), O,O-di- (2-aminoethyl) -dithiophosphate potassium - carbamide-formaldehyde matrix (KD2AEDTP-KFM). Studies were carried out to determine the acid-base properties of covalent-immobilized sulfur-containing ligands - KD2AEDTP-PEM, KD2AEDTP-KFM and the concentration stability of the obtained coordination compounds with ions of copper (II), zinc (II), cadmium (II), and silver (I). Based on the results of integral and differential potentiometric titrations, it was established that the ionization constants (pK) of the dithiophosphoric group in KD2AEDTP-PEM and KD2AEDTP-KFM are 3.23 and 3.35, and the ionization constants of the amino group are 9.76 and 9.63, respectively. As a result of studies of polymer ligands by potentiometric titration via the method of individual weighed portions, it was shown that polyfunctional polymer ligands have the ability to form stable coordination compounds with metal ions of copper (II), zinc (II), cadmium (II) and silver (I). "

STUDY OF THE EVAPORATION PROCESS OF MOTHER LIQUORS IN THE PRODUCTION OF POTASSIUM NITRATE

"The aim was to study the influence of the main technological parameters on the process of evaporation off the primary mother liquors of the filtration process of a potassium nitrate suspension formed as a result of crystallization of the conversion solution at a temperature of 0 °C. A theoretical analysis of the system diagram and experimental data established the sequence of the formation of components during the evaporation of mother liquors. At the same time, in the studied intervals of variation of the parameters, potassium chloride is formed first, and then, the joint crystallization of potassium and ammonium chlorides occurs with the continuation of the evaporation process, and when the evaporation degree is more than 30-35%, the joint crystallization of potassium, ammonium and potassium nitrate chlorides occurs. The process analytical parameters influence of the ratio of the primary mother liquor and ammonium nitrate, as well as, the degree of evaporation have been studied. A nomogram has been developed showing the dependence of the input and output parameters on the value of the residual pressure, and it makes possible to determine the values ​​of the evaporation degree at given conditions. "

ACTIVATION OF WATER USED IN THE PREPARATION OF WHEAT GRAIN FOR VARIETAL MILLING

The purpose of the study is to change the properties of water in order to achieve the optimum impact on wheat grain in preparation for variety milling. The results of influence on the properties of drinking water by acoustic waves in the frequency range of 10-1000 Hz for 1 minute were determined. It is established that the optimal range of exposure is the interval of 80-100 Hz. At the same time water activation is achieved, leading to changes in its properties, such as specific water resistance, electric conductivity, content of dissolved salts, which positively affects the technological indicator - the amount of conductometric ash.

UNDERSTANDING THE PHOTODEGRADATION MECHANISM OF GASEOUS ACETALDEHYDE OVER BI2WO6 — MODIFIED ZNWO4 PHOTOCATALYST UNDER UV LIGHT IRRADIATION

Indoor air quality has a significant impact on human health as people spend more time indoors. As a common indoor air pollutant, acetaldehyde is considered toxic when exposed to it for a prolonged period. The aim of this study is the enhancement of the photocatalytic activity of ZnWO4 with a monoclinic wolframite structure for degradation of gaseous acetaldehyde by modifying its surface with Bi2WO6 layered structure. The mechanisms behind the enhanced photocatalytic activity and the pathways for acetaldehyde photodegradation over the Bi2WO6-modified ZnWO4 photocatalyst are discussed

STUDY OF VARIOUS QUALITY CHARACTERISTICS OF POLYESTER FIBERS OBTAINED ON THE BASIS OF PRIMARY AND SECONDARY POLYETHYLENE TEREPHTHALATE

The aim of study is comprehensive determination of various quality characteristics of polyester fibers obtained on the basis of primary and secondary polyethylene terephthalate. The analysis of the raw material base of pre-oriented yarns (POY) threads has been carried out. The technological, physicomechanical properties, as well as the structure of the primary and secondary polyethylene terephthalate used in the production of the threads have been studied. The structure and properties of polyethylene terephthalate changed: the properties were worse, the structure were amorphous, the molecular weight decreased. The structure of recycled polyethylene terephthalate changed as a result of technological conversions in the production of POY fibers. This is due to a change in the thermophysical characteristics and structure of secondary polyethylene terephthalate under the influence of heat, moisture, and shear stresses. A comparative analysis of the physicomechanical properties of POY yarns obtained from primary and secondary polyethylene terephthalate has been carried out.

THE PRODUCTION OF PLASTIC LUBRICANTS BASED ON REGENERATED SYNTHETIC MOTOR OILS USED IN UZBEKISTAN

The purpose of the study is to increase the efficiency of using used engine oils as a dispersion medium for plastic lubricants. It has been established that the removal of resins, carbenes, carbides and asphaltenes from used synthetic motor oils makes it possible to obtain an oil base close to commercial base oils in terms of basic characteristics; refined oils also have a high margin of operational properties. The composition of lubricants for analogues of Lithol-24 and Solidol-Z based on refined used engine oils has been determined. Anticorrosive, adhesive and strength properties of lubricant compositions are considered.

PERFORMANCE CHARACTERISTICS OF PAINT AND VARNISH MATERIALS FOR MARKING ROADS BASED ON LOCAL RAW MATERIALS

The aim of this work is to develop the technology of obtaining high-performance paintwork materials for road markings on the basis of local raw materials. The existing paint and varnish materials (paintwork materials) for road markings have been studied. Samples of paint and varnish materials for use as road markings were obtained under laboratory conditions. Laboratory and operational tests were conducted to determine the main quality indicators of the paint and varnish materials. As a result of monitoring the condition of road markings for two months it was found that the alkyd-based paintwork material retains its properties (color, adhesion, abrasion resistance) during the observed period and can be recommended as a coating for road markings.