Vol 97, No 7 (2023)

The possibility of initiation of nuclear chemical processes in the Pb cathode during a glow discharge in a low-temperature deuterium-containing nonequilibrium plasma leading to a significant (at times) decrease in the isotope content of some impurity elements (specifically, Zn) and increasing others (specifically, W, Fe, Mn, and Al). Such processes can be understood by introducing the existence in nuclear matter of metastable non-nucleon excitations of internal shaking (isu-states) formed by initiating actions on the nuclei of electrons with high (on chemical scales) kinetic energy Ee ~ 3–5 eV.

Water activities in H2O–CH3SO3H system were obtained by the dew point method and by the static method of a vapor pressure measurement in a temperature range 288.15–323.15 K. Pitzer–Simonson–Clegg model parameters were calculated. The parameters describe adequately properties of a liquid phase in a temperature range 198.15–323.15 К and with an acid concentration up to 80 wt %. Stability parameters were determined for two solid phases, HMS·H2O and HMS·3H2O (HMS = CH3SO3H).

It is established that the rate of the formation of ferrocenium cations in reaction mixture acetylferrocene (1,1'-diacetylferrocene) + I2 + HClO4 as a result of the protonation of metal complexes (MCs) and their oxidation with iodine in dioxane and acetonitrile depends on different mechanisms and is described by kinetic equations obtained by analyzing schemes of the process. The observed difference is due to different roles of the protonation of metal complexes and their oxidation with iodine in these solvents.

Zeolite catalysts for the conversion of dimethyl ether to light olefins with a monoatomic distribution of rhodium are studied via infrared spectroscopy of the diffuse reflection of adsorbed carbon monoxide and X-ray absorption spectroscopy. The zeolite is preliminarily treated with ultrasound to obtain a monatomic distribution of the active component on the support’s surface, and a polymer (chitosan hydrochloride) is used as the medium for dispersing rhodium at the stage of impregnation. A sample prepared via the traditional impregnation of zeolite with an aqueous solution of rhodium chloride is studied for purposes of comparison. It is shown that rhodium in the structure of zeolite treated with ultrasound is in the form of isolated metal centers whether it is deposited with or without a polymer. Synthesis with chitosan results in a more disperse distribution of rhodium on the outer surface of the zeolite and greater oxidizing ability of the catalyst.

Two series of α-hydroxyphosphonate synthesis according to the Abramov reaction are conducted under conditions of microwave activation. Acidic and basic catalysts are used along with 4-bromobenzaldehyde and 3-methoxy-4-hydroxybenzaldehyde. O,O-Diethylphosphite is used as a phosphorylating agent. The conversion of the reaction products is monitored via NMR spectroscopy. The optimum conditions for the synthesis of α-hydroxyphosphonates are selected. The crystal structure of reaction product O,O‑diethyl((4-bromophenyl(hydroxy)methyl)phosphonate 2, which crystallizes in the space group P21/n and is stabilized by multiple C–H⋅⋅⋅O and C–H⋅⋅⋅π interactions, is described for the first time.

The solubility diagram of the ternary system GdCl3–TbCl3–H2O is studied by means of isothermal saturation in ampules at 25°С. A continuous series of solid solutions of isovalent substitution crystallizes in the system GdxTb1−xCl3⋅6H2O.GdTb1−Cl3⋅6H2O. The diagram of solubility in the three-component system GdCl3–TbCl3–H2O at 25°C is calculated according to the classical Pitzer model. Results from experiments agree convincingly with ones from thermodynamic modeling.

The main kinetic laws governing the photochemical degradation of stable cyanide compounds are studied using the example of hexacyanoferrates (HCFs) in the combined {Solar/S2O2−882−} oxidation system under the action of solar radiation. The efficient oxidation of intermediate products (toxic free cyanides) to nontoxic final products proceeds in the combined {Solar/S2O2−882−} system, in addition to the complete degradation of [Fe(CN)6]3− complex. The high efficiency of HCFs oxidation in the combined system is attributed to a conjugated ion-radical mechanism that includes (along with direct photolysis) oxidation with the participation of highly reactive oxygen species (ROSes)—reactive secondary oxidizing agents consisting mostly of hydroxyl radicals generated in situ during the simultaneous alkali and light activation of persulfate with solar radiation. The effect anions (chlorides, sulfates, bicarbonates) and associated organic pollutants (xanthates, phenol) most characteristic of cyanide-containing industrial wastewater have on HCF oxidation in the {Solar/S2O2−882−} system is studied. The studied anions promote HCF photochemical oxidation in a wide range of concentrations (1–10 mM).

Acenaphtho[1,2-k]fluoranthene (1) is synthesized via tandem cyclization during the dehydrofluorination of 1,4-di(1-naphthyl)-2,5-difluorobenzene (2) on activated γ-Al2O3. Presence of residual hydroxyl groups in alumina reduce the yield of target product 1 because of the side hydrolysis of fluoroarenes with the formation a product of partial cyclization, 9-(1-naphthyl)fluoranthen-8-ol (1b). The formation of negative ions (NI) of compounds 1 and 2 in the gas phase is studied by means of dissociative electron attachment (DEA) spectroscopy. Long-lived molecular NIs 1 and 2 are registered at the thermal energies of electrons, and patterns of their fragmentation are established. The adiabatic electron affinities of compounds 1 and 2 are estimated in the Arrhenius approximation and equal 1.17 ± 0.12 and 0.71 ± 0.07 eV, respectively, which agree with data from quantum chemical modeling at the level of the density functional theory (DFT). Electronic transitions for compounds 1 and 2 are studied via optical absorption and fluorescence spectroscopy. Fluorescence quantum yields are measured, and the resulting data are interpreted according to the time dependent DFT. The electrochemical properties of compounds 1, 1b, and 2 are studied via cyclic voltamperometry, and the levels of boundary molecular orbitals are estimated on the basis of their formal potentials of reduction and oxidation.

A study is performed of electron-induced reactions with uracil, thymine, 5-hydroxymethyluracil, cytosine, 5-methylcytosine, and 5-hydroxymethylcytosine. The processes responsible for the formation of negative ions in the studied objects are identified. Features of the formation of the mass spectra of hydroxymethyl derivatives are associated with the abstraction and destruction of substituents. The cross sections of [M–H]− ions are determined in the <3 eV range of energies: (1.1–2.6) × 10−18 cm2 for uracils and (3.6–5.0) × 10−19 cm2 for cytosines.

A possible mechanism is considered for the formation of nanoscale oxides based on titanium and aluminum isopropoxides in a medium of supercritical CO2 fluid. It is shown that because of intermolecular interactions and high pressure in the system, the supercritical fluid acquires the properties of a condensed medium, the main role of which is to restrain processes of hydrolysis. At the first stage of the hydrolysis of titanium isopropoxide, the water molecule is coordinated in the outer sphere of the central atom due to the formation of intermolecular hydrogen bonds. It is then coordinated into the inner sphere with the formation of a five-coordinate transition state and its destruction, creating a product substituted for the hydroxo group. The next steps proceed in a similar way. The described mechanism agrees with experimental findings and produces nanosized X-ray amorphous titanium oxide. (With aluminum isopropoxide, only the hydrolyzed hydroxo form can be produced.) Results suggest the production of nanosized oxides from isopropoxides in a medium of supercritical CO2 fluid is possible for transitional d-elements.

Iron oxide nanopowders are synthesized via chemical precipitation. It is shown that synthesis produces an iron oxide phase with a magnetite structure (either a magnetite–maghemite solid solution or a mixture of this solid solution and goethite). The sizes of the CSR and particles for the main phase are ~10–20 nm. The synthesized iron oxide powders have developed surfaces, specific surface area SBET ≈ 92 and 117 m2/g, and identical fairly large specific pore volumes (VP/P0→0.99/0→0.99 = 0.35 cm3/g). It is shown that additional in situ ultrasonic treatment of the magnetic iron oxide nanoparticles in the mother liquor results in abrupt oxidation of iron(II) ions and creates a nonmagnetic impurity phase of goethite.

Fundamentals of cluster variation (CV) are developed for locally heterogeneous spatially distributed systems. The theory is based on the principles of homogeneous CV in which all variants of the location of the basis cluster on a heterogeneous lattice are additionally considered when it is translated over the system. The structure of the statistical sum of homogeneous CV is shown to remain upon moving to a heterogeneous or homogeneous spatially distributed lattice. However, cofactors of the statistical sum, which previously corresponded to homogeneous clusters, must now consider all arrangements of heterogeneous sites inside each cluster. The general approach is to use a layered structure of the transitional region with variable density between vapor and fluid on a planar square lattice. Explicit expressions for a heterogeneous statistical sum of the transitional region are given on the basis of a 3 × 3 cluster. Using a 2 × 2 cluster, it is shown how an explicit equation for the equilibrium particle distribution in the transitional region can be obtained from the heterogeneous statistical sum. A gradual increase in the size of the m × n basis cluster in the transitional region converges to the exact solution.

The liquid–vapor equilibrium in the toluene–methanol–N-octylquinolinium bromide system has been studied at 101.3 kPa and various concentrations of the organic salt. It was shown that the quinolinium salt can be used as a separating agent for a toluene–methanol azeotrope mixture. For breaking the azeotrope and separating the mixed solvent into components, the N-octylquinolinium bromide concentration (in mole fractions) should be 0.55 or higher.