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 proposes a gas chromatographic method for identifying primary, secondary, and tertiary normal aliphatic amines without using authentic standards. The approach uses Kovats retention indices measured on columns with nonpolar and polar liquid phases, exploiting differences in hydrogen bondin…
This study examines how oxygen-containing anions of transition metals modify the activity of skeletal nickel catalysts in liquid phase hydrogenation of unsaturated compounds. Vanadate, tungstate, and molybdate salts were introduced either during alkaline leaching of a nickel aluminum alloy or direct…
This paper examines the equilibrium distribution of amino acids between aqueous solution and a swollen ion exchanger, emphasizing that amino acid ionization in both phases must be included in the thermodynamic description. Using glycine, and additionally alpha-alanine and asparagine, the authors mea…
This study examines the relationship between bond polarity and bond strength in donor acceptor complexes of tin tetrachloride with organic sulfides. Using dielectric and calorimetric titration, the authors measured dipole moments and heats of formation for complexes with aliphatic sulfides and with …
The study examines how hydrazine vapors and oxygen affect the dark electrical conductivity of thin layers of basic and acid dyes from the triphenylmethane and xanthene series, including both electron and hole organic semiconductors. Conductivity was measured under vacuum after controlled exposure to…
This study examines the high-temperature polymorphism of pure zirconium dioxide and hafnium dioxide, focusing on whether stable cubic phases exist near their melting points. Using a specially designed high-temperature X-ray diffraction chamber with radiative and electron-beam heating in high vacuum,…
This paper reports experimental measurements of phase equilibria in the water, nitrogen system at 330 and 365°C and pressures up to 4000 atm, aimed at determining whether limited mutual solubility of gases occurs in this binary mixture. Using high-pressure sampling and compositional analysis, the au…
This study examines the gamma radiation polymerization of acrolein at low temperatures, with attention to how the monomer state affects polymer structure. Acrolein was irradiated in bulk and in solvents at minus 78 degrees Celsius and as a solid at minus 196 degrees Celsius, and the resulting polyme…
This paper examines conjugation in organophosphorus systems containing a tetrahedral phosphorus atom, focusing on positively charged phosphorus analogs of azacyanines as models for assessing whether phosphorus interrupts or transmits conjugation. The authors synthesize two nominal isomeric phosphaaz…
The paper examines the kinetics of hydrogen oxidation on clean platinum surfaces, with comparison to palladium and silver, under conditions designed to minimize contamination and vary the excess of either hydrogen or oxygen. From pressure-time measurements and graphical differentiation, the authors …
This study examines deuterium exchange of cyclopentane with deuterium over vacuum-evaporated metallic catalysts, comparing Pt, Pd, Ni, W, Mo, and Fe across a range of temperatures. Product distributions were measured mass spectrometrically at low conversion and interpreted in relation to catalyst cr…
This study examines the intrinsic rates of reaction of graphitized carbon black with carbon dioxide and oxygen, addressing discrepancies in prior measurements caused by diffusion effects and changes in carbon structure. Using highly uniform carbon black graphitized at 2800°C and a flow-through layer…
This paper examines how orbital hybridization of halogen atoms influences carbon-halogen bond lengths in halogenated hydrocarbons. Using nuclear quadrupole interaction constants together with electronegativity relationships dependent on orbital S-character, the author estimates hybridization, ionic …
The paper investigates the mechanism of the photochemical arylation of triphenylphosphine by diphenyliodonium borofluoride, yielding tetraphenylphosphonium borofluoride and iodobenzene. Experiments compare irradiation conditions, solvents, reagent ratios, and the effects of radical inhibitors such a…
This paper examines the semiconductor and optical properties of copper, nickel, zinc, and cadmium dithiocarbamate chelates and polychelates in relation to metal content and metal, ligand bonding. Electrical conductivity measurements, thermal activation energies, and electronic absorption spectra in …
The paper develops a kinetic treatment of catalytic and radiation-induced postpolymerization of crystalline solid monomers, emphasizing that chain propagation may be constrained by crystallographic orientation and terminated by lattice defects rather than by ordinary radical competition. It formulat…
High-resolution proton magnetic resonance was used to examine the structure and electron-density distribution of six- and eight-membered organocyclosilazanes bearing dialkyl, alkylaryl, and alkenyl substituents at silicon. Chemical shifts of nitrogen-bound protons were found to be largely independen…
This study examines the mechanism and rate-determining step in the acid-catalyzed hydrolysis of simple vinyl ethers through measurements of the kinetic deuterium isotope effect for the monovinyl ether of diethylene glycol. Hydrolysis rates in ordinary water and heavy water were determined at 20 to 3…
This paper addresses the difficulty of measuring the effectiveness of very weak inhibitors in chain radical polymerization, where conventional kinetic methods are insufficiently sensitive. It argues that in highly viscous media some termination reactions become diffusion hindered, allowing simplifie…
This study examines the temperature dependence of separation coefficients for the isotopic pairs D2, H2, D2, HD, and HD, H2 during sorption of ternary hydrogen isotope mixtures on synthetic zeolites NaA and NaX under isobaric conditions. Using circulation experiments at 90.4, 77.6, and 62.0 K and an…
This paper reports the synthesis and X-ray diffraction characterization of mixed molybdenum chalcogenides derived from molybdenum sesquichalcogenides and elemental chalcogens. Molybdenum sesquiselenide and sesquitelluride were first prepared by direct synthesis from the elements, and six mixed compo…
This study reports the synthesis of uridylyl-(5′→N)-phenylalanyl-3′(2′)-O-adenosine as a model compound for examining possible nucleotide-linked aminoacyl intermediates in protein biosynthesis. The compound was prepared from uridylic acid, converted to a reactive pyrophosphate derivative, and 3′(2′)…
This study examines how monolayers of soluble and insoluble surface-active substances affect energy dissipation in stationary cylindrical surface waves on aqueous systems. Measurements were made for caproic and capric acid solutions and compared with pure water and with insoluble myristic acid monol…
This study examines the thermodynamics of swelling and dissolution of cross-linked polyurethanes in dioxane, with cross-link density varied chemically while maintaining comparable urethane group concentrations. Sorption measurements and calorimetry were used to calculate chemical potentials, free en…
This study examines the nature of irreversible polymorphic transformations in rare-earth oxides, focusing on whether reported C to A or C to B changes are true reversible polymorphic transitions or are coupled to changes in oxygen composition. Using high-temperature vacuum X-ray diffraction up to ab…
This paper develops kinetic equations for two-stage reactions on solid surfaces under general assumptions about surface inhomogeneity. Using a model in which adsorption sites differ by a desorption elasticity and applying the rule relating changes in equilibrium constants to changes in rate constant…
This paper reports low-temperature calorimetric measurements of the true heat capacity of crystalline black phosphorus, a comparatively stable layered modification whose thermodynamic properties had not been measured previously. A high-pressure preparation method was used to obtain a rhombic single-…
This paper examines the termination, or death, of free radicals in polymethyl methacrylate formed by radiation and mechanical action, with particular attention to how radical structure affects stability and reaction pathway. Using electron paramagnetic resonance measurements and analysis of volatile…
This study examines how organic surface-active additives affect the cyanide dissolution rate of gold, motivated by the faster dissolution observed in alkaline acetone cyanohydrin solutions. Using rotating-disk experiments in alkaline potassium cyanide solutions, the authors compare acetone, butyl al…
This paper describes synthetic approaches to complex lipoid compounds related to inositol phosphatides, cephalin derivatives, and phosphatidyl amino acid conjugates. Using protected myoinositol derivatives, phosphorus oxychloride or phosphorodichloridate intermediates, and α,β-distearoylglycerol, th…
This paper reports the synthesis and characterization of hexafluorodimethylhydroxylamine and its oxidation product, hexafluorodimethylnitrogen oxide, from reactions of trifluoronitrosomethane and related intermediates. Gas-phase reaction of trifluoronitrosomethane with ammonia gives hexafluorodimeth…
This study examines the synthesis and polymerization behavior of organocyclotetrasiloxanes in which silicon atoms in the siloxane ring are also incorporated into benzo-fused silicon-containing heterocycles. Hydrolysis and cohydrolysis of 1,1-dichloro-3,4-benzo-1-silacyclohexane with dimethyldichloro…
This paper examines how nickel hydrides can initiate stereospecific polymerization of butadiene and proposes their conversion into soluble pi-allyl, specifically crotyl, nickel complexes as a key stage in active-center formation. Nickel hydrides prepared from anhydrous nickel chloride, ethylmagnesiu…
This paper examines self-ignition in systems where unbranched chain reactions proceed under nonisothermal, adiabatic conditions, focusing on chain-thermal explosions rather than purely thermal or isothermal chain ignition. Using model halogenation schemes for hydrogen, especially hydrogen chlorine a…
This study examines the hydrogen reduction at 1000 degrees C of manganese ferrochromite, MnCr0.25Fe1.75O4, and the phase equilibria of related MnCrxFe2-xO4 spinel solid solutions. Samples prepared by ceramic synthesis were analyzed by X-ray diffraction, gas phase equilibrium measurements, weight los…
This paper examines high-temperature transformations in polyimide films prepared from several tetracarboxylic dianhydrides and diamines through polyamic acid intermediates. By monitoring weight loss, dielectric loss, infrared spectra, and mechanical properties during staged heat treatment, the autho…
This study investigates the structures of two aromatic glycosides, acanthosides B and D, isolated from the roots of Acanthopanax sessiliflorum, a physiologically active plant of the Araliaceae family. Using elemental analysis, acetylation, acid, alkaline, and enzymatic hydrolysis, methylation, chrom…
The interaction of 4,4′-dinitrodiphenylmethane, 4,4′-dinitrodibenzyl, and trans-4,4′-dinitrostilbene with tetra-n-butylammonium hydroxide in dimethylformamide and acetonitrile was studied by electron paramagnetic resonance. The spectra and supporting low-potential electrolysis experiments indicate t…
This paper examines why the stretching vibrational frequencies of thiocyanate and selenocyanate groups change when these ions form coordination bonds through nitrogen, through sulfur or selenium, or as bridging groups. Using approximate normal-coordinate calculations for linear and selected nonlinea…
This study examines catalytic routes to homologs of 1,4-dioxene and 1,4-dioxane, compounds for which earlier syntheses were limited or low yielding. Monofurfuryl ethers of 1,2-glycols were prepared and hydrogenated in the vapor phase over platinized carbon at 140, 180, and 220°C, with products ident…
Infrared absorption spectra were measured for freshly prepared methylates and ethylates of beryllium, magnesium, calcium, strontium, and barium to examine how metal electronegativity and the ionicity of the metal, oxygen bond affect alkoxyl-group vibrations. Comparison with the corresponding alcohol…
This paper systematizes experimental initial heats of chemisorption on comparatively clean metal surfaces and relates them to the structure of surface chemical compounds. It proposes that the initial heat of adsorption is approximately proportional to the number of metal atoms involved in the surfac…
This study examines the electron-acceptor character and microstructure of the sulfofluoride group through ultraviolet spectra of substituted benzenesulfonyl fluorides. By comparing K-band maxima and intensities with those of related sulfonamide, sulfone, carboxyl, acetyl, and nitro derivatives, and …
This study determines standard heats of formation for crystalline zirconium tetrachloride and hafnium tetrachloride, thermodynamic quantities relevant to purification and separation of zirconium and hafnium metals. High purity iodide zirconium and hafnium samples were directly chlorinated at about 4…
The paper addresses the limited availability of stereochemically defined O-furanosides and examines whether sugar orthoesters can serve as general glycosylating reagents for furanoside synthesis, as previously shown for pyranosides. As a test case, the authors prepare the previously unknown 3,5,6-tr…
This study examines the mechanism of nitrogen fixation in the reacting system formed from biscyclopentadienyltitanium dichloride and ethylmagnesium bromide in ether. Using gas analysis, infrared spectroscopy, hydrolysis experiments, and deuterium labeling with deuterated ethylmagnesium bromide and e…
This study uses electron paramagnetic resonance to examine stable free radicals formed in polyimides during heating of polyamic acids and related model compounds. Three radical types are distinguished by their spectra, temperature ranges, concentrations, and stability: an initial broad singlet attri…
This study examines the mass spectra of monocyclopentadienyl titanium derivatives of the series C5H5Ti(OC2H5)3-nCln, with n = 0, 1, 2, and 3, in relation to the character of the titanium to cyclopentadienyl bond. The spectra show molecular ions and characteristic fragment ions formed by loss of chlo…
