SovietRxiv · Open Access in English
Rediscovering the Soviet scientific archive, in English
25357 full-text translations 14926 English PDFs 22539 abstracts
Showing 50 of 4600 papers in Chemistry
This paper examines the high reactivity of peroxide radicals toward divalent manganese stearate in oxidation-reduction processes, a reaction relevant to inhibition and termination in hydrocarbon oxidation chains. Using chemiluminescence from quadratic recombination of peroxide radicals, the authors …
This paper reports the synthesis of polymerizable peroxide esters of acrylic and methacrylic acids as potential peroxide monomers for introducing reactive peroxide groups into polymers. The compounds were prepared mainly by reacting acryloyl or methacryloyl chlorides with sodium salts of alkyl, alky…
This study examines the radiation-induced solid-phase polymerization of hexamethylcyclotrisiloxane under accelerated electron irradiation, with emphasis on how crystalline modification, temperature, dose, and crystal defectiveness affect kinetics. Experiments over the range from minus 196 degrees to…
Infrared spectra of trialkylammonium chloride and bromide solutions in inert solvents were studied to identify spectroscopic manifestations of dipolar association. Changes in concentration and temperature produced reversible redistribution between low frequency and high frequency NH stretching bands…
The paper examines reactions of pentafluorobenzoyl chloride with metal enolates of beta-keto esters as a route to polyfluorinated gamma-benzopyrone derivatives. Condensation with sodium or magnesium ethoxyacetoacetic ester unexpectedly gives 2-methyl-3-carbethoxy-5,6,7,8-tetrafluorochromone rather t…
This study examines intramolecular hydrogen bonding in anils of ortho-hydroxyaldehydes and ortho-hydroxyanils, comparing systems with six-membered and five-membered hydrogen-bonded rings. The authors use experimental dipole moments, additive vector calculations, methyl ether controls, and LCAO molec…
This paper examines solid-phase polymerization of crystalline monomers as nucleation and growth of a polymer phase within a monomer crystal. Using a thermodynamic model of a cylindrical polymer nucleus, the authors relate the critical nucleus size to the surface energy, bulk free energy of polymeriz…
This study examines the chemisorption and electrochemical oxidation of ethane and ethylene on platinized platinum electrodes in acidic and alkaline aqueous electrolytes. Using charging curves and polarization measurements at 20 and 97°C, the authors analyze surface coverage by hydrocarbon residues a…
This paper reports structural studies of the newly isolated alkaloids vinerine and vineridine from the aerial parts of Vinca erecta. Elemental analysis, derivative formation, hydrolysis and remethylation, UV, IR, NMR, and mass spectral comparisons with related compounds are used to establish that bo…
Direct calorimetric measurements were used to determine differential heats of oxygen adsorption on porous silver at 110°C and to examine how small amounts of chemisorbed sulfur alter these heats. Silver samples were pretreated with hydrogen, oxygen was admitted in small portions, and sulfur was intr…
This paper examines the coordination sensitivity of amino-group wagging vibrations in infrared spectra of cyclic ethylenediamine complexes. Extending an earlier argument for ammonia complexes, it relates increases in the wagging frequency to fixation of the nitrogen lone pair by metal coordination, …
This paper examines the mechanism of synergistic inhibition in liquid-phase oxidation when both inhibitors are capable of reacting with chain-carrying radicals. Using initiated ethylbenzene oxidation at 70 degrees, the authors measured oxygen absorption and inhibitor consumption for mixtures of an a…
The paper examines whether the mean chlorine-35 nuclear quadrupole resonance frequency at 77 K can quantify inductive substituent effects in organylchlorosilanes. Using published and measured NQR data for compounds of the RSiCl3, RR'SiCl2, and RR'R''SiCl series, the authors correlate mean resonance …
The study examines vibrational spectra of tetrahedral beryllium complex ions Be(NH3)4 2+ and Be(H2O)4 2+ in crystalline tetraammine beryllium chloride and beryllium sulfate tetrahydrate, with additional isotope substitution using deuterated ammonia and water. Infrared absorption and Raman spectra ar…
This paper determines the stabilization energy of a quasiaromatic six-membered ring formed through intramolecular hydrogen bonding and electron delocalization in the enol form of dibenzoylmethane. The authors measured the heats of combustion of dibenzoylmethane and the ethyl ether of its enolic form…
The paper reports a single-crystal X-ray determination of the structure of orthorhombic gamma-Na2BeF4, undertaken because this compound was expected to model gamma-Ca2SiO4 and direct structural data had been lacking. Using limited zero-level diffraction photographs, Patterson analysis, and compariso…
A series of 2-arylamino-4-phenyl-5-benzoylthiazoles was prepared by reacting dibenzoylbromomethane with potassium thiocyanate in ethanol in the presence of aromatic amines, giving the target thiazoles in moderate to good yields. The structure of the anilino derivative was confirmed by independent sy…
This paper examines the hydrogenation of cis-1,4-polybutadiene using hydrocarbon-soluble Ziegler-type organometallic catalysts as an alternative to heterogeneous metal catalysts. The authors tested systems based on triisobutylaluminum with cobalt, chromium, or titanium compounds in decalin at 80°C, …
This paper examines rapid activation analysis of praseodymium and neodymium in rare-earth materials using 14 MeV neutrons and the dominant inelastic (n,2n) reaction. The authors argue that this approach reduces problems associated with slow-neutron capture analysis, especially self-shielding by elem…
This study examines low-temperature ignition of combustible gas and vapor mixtures brought into contact with heated solid bodies under free-convection conditions, with attention to whether nonthermal autocatalytic processes can lower ignition temperatures. Experiments in thermostated explosion chamb…
This study examines the formation of supramolecular structure in solutions of the helical polypeptide poly-gamma-benzyl-L-glutamate in dioxane using small-angle scattering of polarized light, with parallel microscopic observation. The authors follow concentration- and time-dependent ordering, findin…
This paper analyzes how chain transfer with scission affects the molecular weight distribution of polymers formed in ionic polymerization systems with heteroatoms in the chain. The authors formulate kinetic equations for random reactions between active macromolecules and polymer chains, treating the…
This study examines acid-catalyzed cyclization of alpha- and beta-monocyclofarnesylacetones as a route to stereospecific formation of polycyclic isoprenoid derivatives. Using infrared and NMR spectroscopy, gas-liquid chromatography, and preparative isolation, the authors show that the alpha isomer g…
This paper examines the statistical distribution of right- and left-handed forms in inorganic crystallization, using epsomite crystals grown from aqueous solution as the main experimental case. Handedness indices from multiple crystallization experiments were grouped into distribution curves under v…
This paper examines electrophilic substitution and acid-induced cleavage reactions of triferrocenylphosphine oxide, a compound obtained in high yield by direct phosphorylation of ferrocene. Sulfonation in concentrated sulfuric acid with acetic anhydride gives tris-(1-sulfoferrocenylene-1′)-phosphine…
The paper derives the probability distribution of an internal coordinate of a polyatomic molecule in a vibrational stationary state under the harmonic approximation, a quantity needed in transition configuration theory and theoretical electron diffraction. Since an internal coordinate is expressed a…
The paper reports a method for converting highly condensed hydrolysis lignin, particularly from cottonseed hull processing, into quinone nitropolycarboxylic acids intended as plant growth stimulators. The authors use stepwise oxidation and hydrolysis with nitric acid in aqueous medium at 100°C, foll…
This study examines reactions between ethylene molecules and long-lived, highly excited hydrogen atoms produced by electron impact dissociation of ethylene. Using a two-chamber mass-spectrometric ion source, the work analyzes how ion intensities depend on ethylene pressure and electron energy, disti…
The paper develops a framework for describing extraction in quaternary and higher component systems, where distributed substances influence one another and the Nernst distribution coefficient alone is insufficient. It introduces salting-out coefficients as ratios of distribution coefficients in syst…
This study examines how the thickness of polymer films affects the formation of supramolecular crystalline structures during crystallization from melts. Wedge-shaped films confined between glass surfaces were prepared to provide thicknesses from about 1 to 30 to 40 microns, and structures in gutta-p…
This paper examines the structure of the product formed by the reaction of ethanolamine with trialkyl phosphites, addressing disagreement with a previously proposed open-chain formulation. The authors combine stoichiometric observations, molecular weight and elemental analysis, qualitative chemical …
This study examines the high-temperature decomposition of ethylene containing small additions of radiocarbon-labeled acetylene at 800 to 1000°C and 100 mm Hg, focusing on the role of acetylene in product formation. Using a flow vacuum reactor with complete mixing, chromatographic separation, and rad…
This paper examines nucleophilic substitution reactions of chloromethylcyclopentadienylmanganese tricarbonyl with sodium acetate, potassium phthalimide, and urotropine. The authors prepare and characterize acetoxymethyl, oxymethyl, phthalimidomethyl, aminomethyl, and formyl derivatives, including ac…
This study examines catalytic systems formed from pi-cyclopentadienyl nickel complexes and Lewis acids for the stereospecific polymerization of butadiene. Bis-pi-cyclopentadienylnickel and pi-cyclopentadienyl-pi-cyclopentenylnickel were combined with metal halides, and polymer yields, microstructure…
This study addresses conflicting theoretical predictions for the charge on nickel in nickelocinium, and clarifies earlier X-ray spectral results for nickelocene. Nickel K-edge absorption spectra of nickelocene and nickelocinium triphenylborate were measured with high resolution, corrected for instru…
This study examines how a separated electron donor system affects the color and visible absorption of azomethines containing a nitro-substituted chromophoric donor acceptor system. A series of azomethines with donor substituents of differing strength were synthesized, and their powder colors and sur…
This study examines the molecular structures of the alpha and beta stereoisomers of Delta-3-carene oxide, whose interconversion requires rupture of a carbon-oxygen bond. Vapor electron diffraction patterns were measured and interpreted using radial distribution analysis and successive approximations…
This paper reports the synthesis and characterization of organophosphorus derivatives of azetidine, a class that had previously received little systematic study. Azetidine was reacted with dialkylphosphoric acid chlorohydrides and related phosphorus acid chlorides to prepare a series of dialkylphosp…
The study examines the reaction of dialkylamides of dialkylphosphorous acid with aldehydes, a system that could plausibly yield several types of phosphorus-containing products by analogy with known reactions of phosphorous acid derivatives. Heating equimolar amidophosphites and aldehydes gave nitrog…
This study examines the concentration of surface and intraglobular silanol groups in silica xerogels prepared from hydrogels subjected to hydrothermal treatment at varied temperatures and durations. Total structural water was determined by high temperature calcination, while surface hydroxyls were m…
This paper examines the gamma radiation polymerization of vinyl chloride in frozen solutions of vaseline oil at low temperatures, with attention to the contrast between behavior above and below the melting point of the monomer. Experiments at minus 78 and minus 196 degrees Celsius show strong depend…
Infrared spectra were measured for carbon monoxide adsorbed on ruthenium, rhodium, and palladium between minus 150 and 120 degrees C at pressures near 10^-5 mm Hg and 1.3 mm Hg, in order to examine the proposed formation of both linear and bridged surface complexes on Group 8 metals. The spectra sho…
This study examines how the strongly electrophilic alkylating agent triethyloxonium fluoroborate affects the ambident reactivity of sodium derivatives of acetoacetic ester and acetylacetone. Using ether-phase reactions under heterogeneous conditions, followed by thin-layer chromatography, gas-liquid…
This paper examines the mechanism of complete methane combustion at elevated temperatures, focusing on the elementary radical reactions leading to carbon dioxide and water vapor. Building on Semenov’s low-temperature oxidation scheme, the authors propose a high-temperature chain mechanism that inclu…
This study examines the inhibition of thermooxidative processes in paraffin hydrocarbons by mixtures of anthracene and tetracyanoethylene, with attention to charge-transfer complex and adduct formation. Measurements of induction periods during oxidation of kerosene and ceresin at 180 °C showed that …
This study addresses the preparation of para-aminostyrene, an important intermediate for polymers and organic synthesis, by catalytic conversion of para-aminoethylbenzene as an alternative to multistage low-yield methods. Para-aminoethylbenzene was passed over a mixed oxide catalyst at 560 to 640°C …
This paper reports the synthesis and characterization of several pi-allyl iron tricarbonyl complexes containing iodide, bromide, chloride, nitrate, and a 2-bromoallyl ligand, as well as a triphenylphosphine substitution product. The authors prepare these compounds by reactions of allyl halides with …
This paper examines photochemical arylation of triphenylphosphine with diaryliodonium salts as a preparative route to triphenylarylphosphonium tetrafluoroborates. The authors irradiated acetone or methanol solutions of triphenylphosphine and substituted diaryliodonium tetrafluoroborides or chlorides…
This study applies pulsed nuclear quadrupole resonance at liquid nitrogen temperature to seven chloroalkylchlorosilanes containing both Si-Cl and C-Cl bonds, aiming to relate resonance frequencies to bond polarity and substituent effects. The measured chlorine resonance frequencies show near-linear …
This study systematically examines the mobility of oxygen in rare-earth oxides from lanthanum to lutetium, motivated by their possible use as oxidation catalysts and by links between oxide oxygen mobility and catalytic activity. The authors measured isotopic exchange between molecular oxygen enriche…
