Synthesis of acetic-methacrylic acid diesters of norbornane-2,5-diol and (2-hydroxynorborn-5-yl)methanol

Reaction of addition of acrylic acids to 5-acetoxy- and 5-acetoxymethylnorborn-2-ene in the presence of a BF₃·O(C₂H₅)₂ catalyst was studied in order to synthesize mixed acetic-acrylic acid diesters of norbornane-2,5-diol and (2-hydroxynorborn-5-yl)methanol, which are new monomers for syntheses of polymers.     

Petroleum luminophores of pyrolytic origin and energy transfer between their components

Photoexcitation of luminophores prepared from heavy oil pyrolysis tar was studied, and properties of these compounds, determining the variation of the luminescence color and intensity depending on the solution concentration, were evaluated.     

Reaction of the N,N-dimethylamide and methyl ester of 3-phenyl-3-chloro-2-ketopropionic acid with triphenylphosphine

Conclusions The dimethylamide of 3-phenyl-3-chloro-2-ketopropionic acid reacts with Ph₃P to give -(N,N-dimethyloxamoyl)benzyltriphenylphosphonium chloride. In the presence of methanol, this reaction gives dimethyl(phenylpyruvoyl)amide and Ph₃PO.2. The methyl ester of 3-phenyl-3-chloro-2-ketopropionic acid reacts with Ph₃P to give methoxycarbonylstyryloxytriphenylphosphonium chloride, which, upon heating in benzene at reflux, gives methyl -chlorocinnamate and Ph₃PO.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 6, pp. 1395–1396, June, 1989.     

Spectrophotometric determination of association equilibrium constants of certain phenol substitution derivatives with triethylamine

A spectrophotometric technique was used to determine the association equilibrium constants of phenol, o-isopropylphenol, p-tert-butylphenol, 3,4-, 2,5-, 2, 6-dimethylphenols, and thymol with triethylamine (in an n-heptane medium). The ultraviolet spectra recorded serve as proof of the formation of a hydrogen bond between the hydrogen atoms of the hydroxyl group and the nitrogen atom of triethylamine in these systems (phenol-triethylamine-n-heptane).In conclusion we express out sincere thanks to Prof. V. M. Tatevskii for his interest and valuable advice.     

Magnetic moment relaxation of a shallow acceptor center in heavily doped silicon

Results of studying the temperature dependence of the residual polarization of negative muons in crystalline silicon with germanium (9×10 ¹⁹ cm ^?3 ) and boron (4.1×10 ¹⁸ , 1.34×10 ¹⁹ , and 4.9×10 ¹⁹ cm ^?3 ) impurities are presented. It is found that, similarly to n-and p-type silicon samples with impurity concentrations up to ～10 ¹⁷ cm ^?3 , the relaxation rate ν of the magnetic moment of a _μ Al acceptor in silicon with a high impurity concentration of germanium (9×10 ¹⁹ cm ^?3 ) depends on temperature as ν～T ^q , q≈3 at T=(5–30) K. An increase in the absolute value of the relaxation rate and a weakening of its temperature dependence are observed in samples of degenerate silicon in the given temperature range. Based on the experimental data obtained, the conclusion is made that the spin-exchange scattering of free charge carriers makes a significant contribution to the magnetic moment relaxation of a shallow acceptor center in degenerate silicon at T?30 K. Estimates are obtained for the effective cross section of the spin-exchange scattering of holes (σ _h ) and electrons (σ _e ) from an Al acceptor center in Si: σ _h ～10^?13 cm² and σ _e ～8×10^?15 cm² at the acceptor (donor) impurity concentration n _a (n _d )～4×10¹⁸ cm^?3.     

Measurements of the magnetic moment of the negative muon in the bound state in various atoms

The magnetic moment of the negative muon in the 1s state was measured in carbon, oxygen, magnesium, silicon, sulfur, and zinc. The attained precision of measurements allowed the dependence of the relativistic correction to the magnetic moment of the bound muon on the charge of the nucleus to be verified.     

Kinetics of H2S destruction in the radiolysis of CH4−H2S gas mixtures

The kinetics of H₂S destruction in the radiolysis of CH₄–H₂S and CH₄–H₂S–O₂ mixtures has been studied. It has been shown that G(–H₂S) depends on amounts of hydrogen sulfide and the presence of oxygen in the starting mixture and is within the range of 5–13 mol/100 eV. G(H₂) decreases with the increases of O₂ content and amounts to the constant value of 2.