Mechanism of Deuterium Distribution in Ethanols

Deuterium distribution in ethanols produced by sulfuric acid hydration of ethylene was studied by quantitative NMR spectroscopy.     

19F NMR study of fluorinated mono- and diacylhydrazines

Conclusions It has been demonstrated by means of¹⁹F NMR that l-acyl-2-alkyl (phenyl) hydrazines are the main products of the monoacylation of alkyl- and phenylhydrazine with derivatives of perfluorocarboxylic acids. The preferred conformations with respect to the amide bond have been determined in mono- and di (perfluoroacyl) hydrazines.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2735–2739, December, 1980.     

Bioconversion of D-glucose in heavy water: Effect of water isotopomeric composition on deuterium fragment distribution in ethanol

The relative distribution of deuterium between methyl and methylene groups in ethanol at the bioconversion of D-glucose in heavy water was studied.     

Quantitative1H and13C NMR spectroscopies of cottonplant dioxane lignin

A comparative analysis has been made of the dioxane lignins of the stems, seedling shoots, and seed coats of the cotton plant. The ratio of p-hydroxyaromatic, guaiacyl, and syringyl units in the macromolecules of the lignins has been determined, and so have the amounts of functional groups and bonds. It has been established that the main difference between the dioxane lignins from seedling shoots and seed coats of the cotton plant, on the one hand, and the lignin from the woody stems, on the other hand is a lower content of syringyl and guaiacyl units in the former.     

Modelling of anisotropic sintering in crystalline ceramics

We present a model that describes anisotropic shrinkage during sintering in a powder compact of aligned, elongated particles by deriving the anisotropic sintering stress and the anisotropic generalized viscosity as a function of material and geometric parameters. The powder compact consists of elongated particles, which are perfectly aligned and simply packed with elliptical pores at all the quadra-junctions between the particles. The model considers mass transport by grain boundary diffusion and surface diffusion. Shrinkage rates are calculated for a variety of geometries and are compared to kinetic Monte Carlo simulations.     

Synthesis of 2-thiabicyclo[3.2.0]hept-3-enes by reaction of acetylene with sodium sulfide

The previously unknown2-thiabicyclo[2.3.0]hept-3-ene and exo- and endo-6-methyl-2-thiabicyclo[3.2.0]hept-3-enes were synthesized in one step from acetylene and sodium sulfide in aqueous dimethyl disulfoxide.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 7. pp. 895–899, July, 1976.     

Schematic structure of a fragment of the cottonplant lignin macromolecule

A schematic structure has been proposed for an average fragment of the macromolecule of cottonplant dioxane lignin on the basis of the results of a chemical study and quantitative¹H and¹³C NMR spectroscopy.Translated from Khimiya Prirodnykh Soedinenii, No. 2, pp. 234–236, March–April, 1996. Original article submitted June 27, 1994.