Russian Journal of Applied Chemistry最新文献

The effect of a constant magnetic field on the adrenaline oxidation was studied, and the oxidation kinetics was analyzed. The relationships found suggest the leading role of the superoxide radical. The magnetic field increases the disproportionation rate of superoxide radicals, decreasing their concentration and thus decreasing the oxidation rate. Introduction of superoxide dismutase and an increase in its amount lead to a decrease in the rate of the adrenaline consumption via oxidation. The exposure to a magnetic field in the presence of superoxide dismutase leads to still more pronounced reaction deceleration.

The main aspects, state of the art, and prospects for the development of technologies for solvent-free deoiling of slack waxes are discussed. The limiting factors affecting the development of solvent-free deoiling technologies and their implementation in flowsheets of oil blocks of petroleum refineries are the batch mode of the process and low efficiency of processing high-boiling slack waxes. Thermal deoiling processes become topical owing to the technological flexibility allowing production of a wide range of paraffin wax products, low operation expenditures, and low environmental impact due to the absence of toxic solvents. The use of solvent-free deoiling technologies will allow the range of paraffin wax products to be considerably expanded.

In the present work thermal atomic layer deposition (ALD) of aluminum-molybdenum oxide films (Al_xMo_yO_z) using trimethylaluminum (TMA, Al(CH₃)₃), molybdenum dichloride dioxide (MoO₂Cl₂) and water was studied. The possibility of ALD molybdenum oxide (MoO₃) film using MoO₂Cl₂ and water was also examined. The film growth process was studied in situ using a quartz crystal microbalance (QCM) technique and ex situ using various spectroscopic methods. ALD of Al_xMo_yO_z was carried out using supercycles consisting of TMA/H₂O and MoO₂Cl₂/H₂O subcycles. The subcycle ratios were 1 : 1 and 1 : 7, which are designated as 1Al1MoO and 1Al7MoO, respectively. At 150°C, film growth is linear with a growth rate of 5.39 and 7.62 Å per supercycle for 1Al1MoO and 1Al7MoO, respectively. The density of the films were 3.44 and 3.80 g/cm³ for 1Al1MoO and 1Al7MoO, respectively. The 1Al1MoO film with a thickness of 215.8 Å had a roughness of 10–12 Å, and the film obtained from the 1Al7MoO process with a thickness of 228.7 Å had a roughness of 16–18 Å. The synthesized thin films were characterized with XPS, XRR, SE, and XRD. The oxidation state of molybdenum in the Al_xMo_yO_z films is +6, +5, and +4. X-ray diffraction analysis showed that the films had an amorphous structure.

By varying the ratios of ammonium heptamolybdate, nitrilotriacetic acid, and 2-aminoethanol, a concentrated solution of the molybdenum complex was obtained, which is stable during long-term storage and does not cause the formation of a solid precipitate. In an aqueous solution, 2-aminoethanol replaces ammonium groups in ammonium heptamolybdate, giving mixed ammonium-amine derivatives (NH₄)_n(NH₃CH₂CH₂OH)_6–n[Mo₇O₂₄], which induce solution instability and precipitation. Ammonium cations in the HMA molecule can be completely replaced by 2-aminoethanol cations when carrying out the reaction in an aqueous medium with a sixfold molar excess of 2-aminoethanol to obtain the hexaamine derivative (NH₃CH₂CH₂OH)₆[Mo₇O₂₄]. In the ternary system ammonium heptamolybdate–nitrilotriacetic acid–2-aminoethanol, the formation of highly soluble triammonium [trioxo(nitrilotriacetato)molybdate] hydrate (NH₄)₃[MoO₃L]∙H₂O (1) occurs, the crystal structure of which was studied by X-ray diffraction analysis. Using red clover as an example, it was shown that the resulting solution is agronomically more effective in comparison with a solution of a molybdenum complex with (1-hydroxyethylidene)-diphosphonic acid.

The interaction of α-alkenes, styrene, methylstyrene with elemental sulfur (S₈) in an ultrasonic cavitation field in the exposure mode of 22 kHz, 30 W was studied. It has been shown that under conditions of ultrasonic cavitation, active radical ions ⁺S^• and biradicals ^•S^• are formed. New directions for the reaction of alkenes with S₈ under these conditions have been discovered: the hydrogenation of alkenes occurs parallel to the sulfurization process. The reaction of S₈ with α-olefins under the influence of ultrasound affords 4-alkyl-1,2,3-trithiolan-5-thiones, 2,5-dialkylthiophenes, and alkanes; with styrene—2,4-diphenylthiophene; with methylstyrene—4-phenyltrithione.

In the propylene oxide and styrene coproduction (PO/SM) process, styrene is produced by the catalytic dehydration of 1-phenylethanol in the presence of alumina. In addition to hydrocarbon flow, direct steam is supplied to the reactor to regulate the thermal regime and reduce the rate of side reactions and the rate of catalyst deactivation. In this work, the contribution of acid sites of different natures and strengths to the activity of catalysts based on alumina in the dehydration of 1-phenylethanol, which occurs in the presence of excess water in the temperature range of 230-300°C, was assessed. A series of catalysts were prepared using the impregnation method from aqueous solutions of sodium carbonate, ammonium molybdate, ammonium metavanadate and ammonium tungstate. The acidity of the catalysts was studied using low-temperature adsorption of carbon monoxide. The dehydration reaction is not associated with Brønsted acid sites present on the surface of alumina (frequency range of CO absorption bands ν_CO = 2155-2165 cm^–1). In the presence of Lewis acid sites of varying strength on the surface of the catalyst (ν_CO = 2238–2240, 2203–2210, and 2189–2195 cm^–1) in the temperature range up to ~250°С, the contribution to the integral dehydration of the weakest Lewis acid sites (ν_CO = 2189–2195 cm^–1) did not exceed 20%. All transition metals increase the concentration of Lewis acid sites (ν_CO = 2238–2240, 2203–2210 cm^–1), which leads to an increase in the dehydration activity of catalysts toward 1-phenylethanol.

The micro holes produced using electrochemical micro machining (ECMM) process emphasis the accuracy and surface finish of micro hole due to its nature of machining. Hence, this paper attempt with different salt free electrolytes and its results are compared with normal electrolyte. The electrolyte such as sodium nitrate mixed electrolyte (SONE), copper mixed electrolyte (CUME), sulfuric acid mixed electrolyte (SFAE) and mixer of these entire materials in equal ratio considered as composite electrolyte (COME) are used for experiments. The optimization techniques such as Weighted Aggregated Sum Product Assessment (WASPAS) and Multi-Objective Optimization on the basis of Ratio Analysis (MOORA) are used to determine the best machining combination. The results obtained with experiments noted that maximum MRR, i.e., 1.8887 µm/s is obtained in COME with the parameter combination of 7 V machining voltage, 90% duty cycle and 38°C electrolyte temperature which is 98.23% higher than the SONE. Furthermore, field emission scanning electron micro scope (FESEM) image analysis and energy dispersive X-ray spectroscopy (EDX) are carried out on the micro holes to know the clarity over the effect of electrolyte on surface quality of micro hole.

The paper presents the results of a study of the influence of the dressing process of a hollow aluminosilicate microsphere on the structural features and regulaties of changes in the main physical and mechanical characteristics of composites based on polypropylene graft copolymer with methacrylic acid. Organosilicon compound АГМ-9 (γ-aminopropyltriethoxysilane) was used as a dressing size. The mechanism of the sol-gel reaction in the process of dressing the surface of microspheres is given. The introduction of dressed microspheres into the composition of the graft copolymer made it possible to obtain hybrid composites with improved physical and mechanical properties. The most probable mechanism for the formation of the structure of hybrid composites with the formation of a three-level cross-linked spatial structure - “interpenetrating networks” is considered. The use of the method of thermomechanical studies of dressed and undressed composites confirmed the assumption of the formation of interpenetrating networks.

The use of fungal raw materials for preparing various biocomposites is a promising research direction. Data on using fungal raw materials for preparing chitosan, in particular, films based on the chitosan–glucan complex, are insufficient, which determined the goal of this study. Chitin from fungal biomass, converted to chitosan by deacetylation, shows promise for preparing functional film hybrid polymer biocomposite materials. This study deals with film samples based on the chitosan–glucan complex obtained from the biomass of fruiting bodies of higher fungi. The study was aimed at preparing film materials based on the chitosan–glucan complex and at determining their structure and mechanical and physicochemical properties. The chitosan–glucan complex (CtsGC) was prepared by base hydrolysis of the chitin–glucan complex, and film materials, by wet forming onto a support. The mechanical and physicochemical properties were studied using thermogravimetric analysis, differential scanning calorimetry, and thermomechanical analysis. The film microstructure was examined using scanning electron microscopy. The forming resulted in significant texturing of the external surface relief: (1) interwoven fibrous thickenings consisting of residues of incompletely dissolved CtsGC particles are clearly seen; (2) there are closed micropores with the transverse size from 100 to 1000 nm; (3) there are local flat druses of lamellar crystals. The tensile strength of the film is up to 2.9 MPa, the elastic modulus is up 70 MPa, and the relative elongation at break is up to 14%. The water content of the film reaches 15 wt %. The product is thermally stable up to 200℃ and then gradually degrades in several steps. The results can be used for (1) preparing experimental samples of hybrid biocomposite films with various fillers, (2) assessing the possibilities of using biocomposite films, and (3) developing a future integrated technology for processing the readily renewable non-food vegetable resources into products demanded by the Russian economy.

The paper shows the potential possibility of using vermiculite and eggshell as fillers for polymers of increased thermal stability. Formulations of PVC compositions with the content of the studied fillers have been compiled. The synergism of the effect of these additives on the thermoanalytical characteristics of PVC compositions has been studied. The joint effect on the rheology of compounds with their contents has been determined.