Voprosy Khimii i Khimicheskoi Tekhnologii
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Published By Shei Ukrainian State University Of Chemical Technology

2413-7987, 0321-4095

Author(s):  
M.-O.М. Danyliak ◽  
◽  
I.М. Zin ◽  
O.P. Khlopyk ◽  
M.Ya. Holovchuk ◽  
...  

The anticorrosion environmentally friendly pigments based on synthetic zeolite for paint coatings were obtained by liquid-phase ion exchange method. Zeolite was modified with zinc, calcium and manganese ions. The corrosion resistance of 09G2C steel in 0.1% NaCl solution and in suspensions of modified zeolite was investigated by potentiodynamic polarization method. It was shown that the use of zeolite modified with cations of divalent metals contributes to the reduction of corrosion currents. It was found that the zeolite modified with zinc cations exhibits the most anticorrosion effect relative to 09G2C steel, as indicated by the values of corrosion currents (which are ~2 times smaller than in the non-inhibited solution) and the results of electrochemical impedance spectroscopy. The surface morphology of 09G2S steel after exposure to the inhibited media was determined by scanning electron microscopy. Protection mechanism of the modified zeolite was suggested.


Author(s):  
Ashwini Swaminathan ◽  
◽  
Ranjithkumar Ravi ◽  
Sakunthala Ayyasamy ◽  
Vidhya Bhojan ◽  
...  

The PVA–NH4SCN polymer membranes were prepared by simple solution casting technique by passing ultrasound waves during the preparation. The polymer membranes were subjected to X-ray diffraction analysis and scanning electron microscopy. The X-ray diffraction pattern confirmed the incorporation of a salt into the polymer matrix. The scanning electron microscopy images showed the morphological changes of the polymer membrane. The polymer electrolyte (designated as UPVA20) incorporated with the 20 wt.% of the salt had the highest electrical conductivity in the order of 10–4 S cm–1. It was concluded from the dielectric, tangent and modulus spectra that the UPVA20 membrane was good at its properties. Thus, electric double layer capacitor was constructed with UPVA20 membrane as the separator. The capacitance value of the electric double layer capacitor determined from cyclic voltammetry was found to be 1652 mF g–1. The ultrasound assisted preparation of polymer membranes were good at performance when compared with the polymer membranes of ultrasound unassisted preparation. Among all the polymer electrolytes, UPVA20 polymer membrane had high conductivity, potential stability and capacitance.


Author(s):  
A.O. Musina ◽  
◽  
O.O. Sihunov ◽  
O.P. Ryzhova ◽  
O.S. Sverdlikovska ◽  
...  

The paper deals with the structure and phase composition of non-autoclave aerated concrete with a density of 600–800 kg m–3 using ferrosilicon as a gasifier. The conditions of formation of porous structure of aerated concrete and preparation of calcium hydrosilicates were considered. Phase composition of the samples was investigated by means of X-ray phase analysis and differential thermal analysis. Analysis of X-ray patterns showed that the test samples contained tobermorite 11.3 Å (5CaO6SiO25.5H2O), xonotlite (6CaO6SiO2H2O) and -dicalcium silicate hydrate (2CaOSiO2H2O) as a binder. It was established that there is an increase in the content of hydrosilicate phases with an increase in the content of gasifier in the vast majority of cases. The obtained data were confirmed by the results of differential thermal analysis.


Author(s):  
K.B. Podbolotov ◽  
◽  
A.T. Volochko ◽  
G.V. Lisachuk ◽  
R.V. Krivobok ◽  
...  

Ceramic materials were synthesized in the RO(R=Ba, Sr)–Al2O3–SiO2 system using exothermic synthesis from solutions containing barium and strontium nitrates, silica and organic reducing agents (glycine and carbamide). It was shown that only the use of a mixture of glycine and carbamide as well as the addition of ammonium nitrate allows carrying out a complete exothermic synthesis with the formation of an X-ray amorphous product with a small fraction of the crystalline phase. It was established that monophase materials based on barium and strontium aluminosilicates (BaAl2Si2O8 and SrAl2Si2O8) are formed when the obtained X-ray amorphous product is heat-treated at the temperatures above 10000C. Ceramics from synthesized materials sintered at 15500C has a high refractoriness, open porosity of 0–1.0%, compressive strength of 115–120 MPa; dielectric constant of 3.25–6.0 (at the frequency of 1 MHz) and the loss tangent of (1.5–5.2)10–3. The results shows that the exothermic synthesis ensures the preparation of nano- and sub-microcrystalline powders in the system RO(R=Ba, Sr)–Al2O3–SiO2. Materials based on the obtained aluminosilicates can be used in the manufacture of protective structures for devices operating in the radio frequency band, in radar installations of aviation and rocket technology, in microwave elements, etc.


Author(s):  
О.V. Savvova ◽  
◽  
O.I. Fesenko ◽  
G.K. Voronov ◽  
V.D. Tymofieiev ◽  
...  

The efficiency of the use of IR spectroscopy in studying the structure of magnesium-aluminosilicate glass-ceramic materials was analyzed. It was established that the formation of the structure of these glass-ceramic materials during the heat treatment is associated with a distortion of the cordierite structure. The presence of solid solutions, high and low cordierite in the structure of the materials under study was detected according to the systems of bands F2, E2, C2 and D2, depending on the temperature of their heat treatment. The mechanism of phase formation in magnesium-aluminosilicate glass-ceramic materials has been determined, which consists in the formation of future crystals of -cordierite and spinel at the initial stages of nucleation, and crystals of -cordierite and mullite at the stage of crystallization. Formation of a finely dispersed glass-ceramic structure with a predominant content of -cordierite or mullite under conditions of low-temperature heat treatment is a decisive factor in ensuring high thermal and mechanical properties of glass-ceramic materials. This allows them to be used as structural elements of devices and equipment under thermal and mechanical loads.


Author(s):  
A.I. Zahrai ◽  
◽  
Z.I. Borovets' ◽  
I.V. Lutsyuk ◽  
Yа.M. Novitskyi

The method of mechanical activation of hydrated lime in a vibrating activator of bunker type was offered in this work. The influence of design features and angle of fixing of vibrating blades on the speed and degree of dispersion of hydrated lime was investigated by measuring the change in the logarithmic decrement of mass attenuation during vibro-activation. The effect of the duration of the vibro-activation process on the dispersion in the system "hydrated lime–water" was studied. The efficiency of lime dispersion was shown in the case of mounting the blades at the angle of 860 for 40–60 minutes. Comparative studies of the strength of cement stone showed that the addition of vibro-activated hydrated lime in an amount of 2 wt.% leads to an increase in the strength of lime-cement compositions.


Author(s):  
Y.M. Pushkarev ◽  
◽  
S.V. Saitarly ◽  

The effect of shungite on the structural and viscous-flow properties of compositions based on oligobutadiene was studied. The strength of coagulation structures of ebonite compositions filled with shungite was determined. The critical filling concentration was established and it is 40 wt.% of shungite per 100 wt.% of oligobutadiene. It was shown that increasing the temperature from 200C to 800C leads to a significant reduction in the shear stress required to destroy the structure of the composition. Temperature and shear rate independently affect the structured composition. Thus, it was shown that shungite powder can be used as a filler in liquid ebonite compositions based on oligobutadiene.


Author(s):  
S.V. Pysarenko ◽  
◽  
V.Yu. Chernenko ◽  
O.E. Chygyrynets ◽  
O.M. Kaminskiy ◽  
...  

X-ray spectral studies of the chemical composition of Irshansk ilmenite concentrates showed that it is leukoxenized mineral with a high (up to 79%) content of titanium oxide and inclusions of pseudorutile. The process of alkaline leaching of Ti4+ from ilmenite is investigated in the work. The study of the temperature effect on the reaction of ilmenite with potassium hydroxide at atmospheric pressure revealed that a temperature of 453 K is sufficient to obtain potassium titanate. A further increase in temperature does not provide a significant increase in the yield of water-soluble titanium. It is found that the optimal and sufficient ratio between ilmenite and potassium hydroxide is 1:2. An increase in the amount of potassium hydroxide in the reaction mixture is unsuitable, since it reduces the yield of soluble titanium and the final product will have a high alkalinity due to the presence of alkali which did not react. The main process of leaching with the formation of solid melt is completed in the first 30 minutes of the process. Infrared spectroscopy and X-ray diffraction showed that potassium titanate (K2TiO3) is formed under the studied conditions of alkaline leaching of ilmenite.


Author(s):  
D.Zh. Kut ◽  
◽  
M.M. Kut ◽  
M.Yг. Onysko ◽  
V.G. Lendel

The paper presents the results of the study of the process of electrophilic intramolecular cyclization of 3-methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones by tellurium tetrahalides. 3-Methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones were prepared by the alkylation of the corresponding thions with propargyl bromide in an alkaline alcohol medium. It is found that the interaction of propargyl thioethers of 3-substituted 2-thioxo-7-(trifluoromethyl)-2,3-dihydroquinazolin-4(1H)-ones with tellurium tetrahalides, which were obtained in situ from tellurium dioxide and six equivalents of corresponding concentrated hydrohalic acid, leads to the formation of halides of angular 4-methyl(phenyl)-5-oxo-1-((trihalotellanyl)methylidene)-8-(trifluoromethyl)-1,2,4,5-tetrahydrothiazolo[3,2-a]quinazolin-10-iums. The most optimal conditions for the tellurium-induced electrophilic heterocyclization of propargyl thioethers with tellurium terahalides are the use of glacial acetic acid as a solvent and stirring of the reaction mixture at room temperature for 24 hours. It is found that the electrophilic cyclization of 3-methyl(phenyl)-2-(prop-2-yn-1-ylthio)-7-(trifluoromethyl)quinazolin-4(3H)-ones by tellurium tetrahalides occurs stereoselectively with the formation of one configurational isomer. The influence of the nature of halogen in the electrophilic reagent and the substituent in position 3 of quinazoline is examined and it is found that these factors do not affect the regioselectivity of the electrophilic intramolecular cyclization process. As a result of the conducted study, potentially biologically active salts of tellurofunctionalized thiazolinoquinazolines of angular structure were received.


Author(s):  
A.I. Karkhut ◽  
◽  
Kh.B. Bolibrukh ◽  
O. Khoumeri ◽  
O.O. Vashchenko ◽  
...  

The cyclocondensation of the bielectrophile 2,3-bis(bromomethyl)-1,4-dimethoxyanthracene-9,10-dione with several heteroyl-benzyl hydrazides with the formation of exofunctionalized tetracyclic quinoid systems was studied. Different numbers of products were isolated by liquid chromatography for different hydrazides. The products were identified as atropisomers. Generally, only one isomer was isolated for N'-(4,6-dimethylpyrimidin-2-yl)benzohydrazide, while two and three isomers were isolated for N'-(6-chloropyridazin-3-yl) benzohydrazide and for N'-(4-chlorophthalazin-1-yl) benzohydrazide, respectively. To determine their structure, modeling of the geometries and NMR spectra by DFT methods was performed. The structure of the obtained isomers was established based on 1H, 13C NMR and NOESY spectra, the results well agree with the simulation results.


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