Russian Journal of Applied Chemistry最新文献

This study impregnated polyurethane (PU) into a nonwoven polyethylene terephthalate (PET) fabric. Polyurethane was prepared by a facile and green method using polyols with different ratios of polyethylene glycol (PEG)/(Polyvinyl butyral (PVB) + waste sodium lignosulfonate (SLS)) and hexamethylene diisocyanate. Fourier-transform infrared spectroscopy (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD) were used to examine the non-woven PET-treated and untreated samples. The results indicated that the treated solution was successfully impregnated on the nonwoven polyester surface, which affected the morphology. Derivative thermogravimetric analysis (DTG), thermogravimetric analysis (TGA), mechanical properties, and antifungal properties were studied. The results depicted that the treated nonwoven PET became more thermally stable than untreated nonwoven PET with an increasing percentage of (PVB + SLS). The mechanical properties showed a noticeable improvement in tensile strength and Young’s modulus, while elongation decreased by increasing the (PVB + SLS) ratio. It was discovered that weight loss decreased after researching the impact of UV light. PU modified with PVB+SLS exhibited enhanced antifungal activity of nonwoven PET due to the natural antimicrobial properties of SLS. This modification not only improves the resistance of the material to fungal growth but also expands its application potential in various industries, including healthcare, construction, and consumer goods. The sodium lignosulfonate examined in this study exhibits promise for use as a reactive polyol component in the synthesis of PU.

The features of forming film materials based on acid-soluble chitosan are investigated. The dependence of the physicomechanical and sorption properties of the film materials on the amount of the introduced cross-linking agent (glutaraldehyde) and plasticizer (polyoxyethylene glycol) was found. The use of glutaraldehyde is proposed to control the sorption of aqueous media by chitosan-based film materials due to the formation of cross-links that afford the films with water absorption of 200–650% (without adding cross-linking agents and plasticizers—up to 40%). Non-toxic chitosan film materials with more than 90% cell survival rate during incubation with the studied materials were fabricated. The obtained materials have required level of hydrophilic-hydrophobic properties (wetting angle was up to 90°) and physicalmechanical properties (strength and relative elongation were 10–12 MPa and 4–10%, respectively). The possibility of biodegradation of the fabricated films under conditions of soil degradation is shown, which can be applied to create materials with programmed degradation.

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.

This manuscript presents a novel approach for green hydrogen production through ethanol electrolysis using Co/Ni bimetallic nanoparticles-incorporated carbon nanofibers (CNFs). The synthesis method involves the electrospinning of a sol-gel comprising nickel acetate, cobalt acetate, and poly(vinyl alcohol), followed by vacuum drying at 60°C overnight and subsequent calcination in a vacuum atmosphere. X-ray diffraction (XRD) analysis revealed the decomposition of acetate precursors, resulting in the formation of zero-valent metal nanoparticles (NPs). Transmission electron microscopy (TEM) confirmed the alloy composition of the NPs. Electrochemical measurements demonstrated the effective utilization of the proposed nanofibers as anode materials in ethanol electrooxidation reactions for hydrogen production at low voltage. Optimization of the metallic nanoparticle composition was found to significantly enhance performance. For instance, Ni- and Ni_0.9Co_0.1-doped CNFs exhibited current densities of 37 and 142 mA/cm², respectively. Especially, Ni_0.1Co_0.9-doped CNFs displayed a remarkably low onset potential of -50 mV vs. Ag/AgCl. Moreover, Ni_0.9Co_0.1-doped CNFs exhibited the ability to recover hydrogen from ethanol solutions from 0.1 to 5 M, attributed to the observed active layer regeneration. The versatility of ethanol as a feedstock, derived from biomass fermentation, positions the proposed anode materials as sustainable catalysts for green hydrogen production from agricultural sources. This work underscores the potential of Co/Ni bimetallic nanoparticles-incorporated CNFs in advancing the field of renewable energy and promoting sustainable H₂ generation.

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.