Estimation of a translation parameter with the help of order statistics

Investigation of the asymptotic behavior of estimates of the translational parameter with the help of linear combinations of order statistics for Symmetrie distributions.Translated from Staticheskie Metody, pp. 116–121, 1978.The author thanks Yu. N. Tyurin for his discussion of the results and helpful comments.     

Phytoestrogens

Conclusions 1. Eight new representatives of methyl- and methoxycoumestans were obtained.2. For the synthesis of the coumestans, the following previously undescribed coumarins have been synthesize 4,7-dihydroxy-5-methyl-, 4,7-dihydroxy-5-methoxy-, and 4-hydroxy-7-methoxy-5-methylcoumarins.Khimiya Prirodnykh Soedinenii, Vol. 6, No. 3, pp. 355–358, 1970.For part IV, see [4].     

Mass-spectrometric study of benzopyridosilaazepines and -azepinones

The influence of various structural factors on the dissociative ionization of benzopyridosilaazepines and -azepinones has been investigated. It has been shown that the mass spectra can be used to identify isomeric benzopyridosilaazepinones with respect to the position of the amide fragment in the central heterocycle. The anomalously high intensity of the ion [M-H]⁺ in the mass spectra of these compounds is attributed to fragmentation of the molecular ions from the open form.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 5, pp. 704–707, May, 1986.     

Oxidation of aniline with solutions of Mo—V-phosphoric heteropolyacids

Mo—V-phosphoric heteropolyacids (HPA) can be used for aniline oxidation to polyaniline or 1,4-benzoquinone. At room temperature and the molar ratio HPA : aniline = 0.67, more than 95% substrate are oxidized to polyaniline. At 90–100 °C and HPA : aniline = 3, the substrate is quantitatively oxidized to 1,4-benzoquinone. Solutions of HPA are regenerated by oxygen in a separate step. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 6, pp. 1488–1490, June, 2005.     

Influence of porous support structure and active component composition on deactivation of vanadium catalysts in SO2 oxidation

The effect of porous support structure and active component composition of vanadium catalysts on the crystallization character of this component has been studied in SO₂ oxidation at low temperatures and conversion degrees. The tendency to crystallization is shown to drop with decreasing support pore radius and with increasing K/V molar ratio.

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. , K/V.

     

Catalytic oxidation of organic compounds with oxygen in the presence of Mo-V-phosphoric heteropoly acid solutions

The studies carried out at the Institute of Catalysis, Siberian Branch, Russian Academy of Sciences, on the selective catalytic oxidation of organic compounds with oxygen in the presence of aqueous solutions of Mo-V-phosphoric heteropoly acids (HPAs) are reviewed. Alkylphenols are oxidized into 1,4-quinones with a selectivity of 85–99%, and C₂-C₄ olefins in the presence of Pd complexes are oxidized into carbonyl compounds with a selectivity of 98–99%. The bifunctional (acidic and oxidizing) properties of HPA solutions were used for the first time to synthesize anthraquinones and vitamin K₃.     

Radical Polymerization of Protonated Diallylammonium Monomers in Bidistilled Aqueous Solution: Kinetic Study

The kinetics of the radical polymerization of protonated monomers of the diallylammonium series (diallyl- and diallylmethylammonium trifluoroacetates) in bidistilled aqueous solution (quartz bidistiller) is studied in situ using ¹Н NMR spectroscopy. The rates of monomer consumption and polymer accumulation in the range of 30–50°С are determined. For diallylammonium trifluoroacetate, the effective activation energy of polymerization and the constant of chain transfer to the monomer (30°С) are estimated. It is found that the initial rates of polymerization are comparable with the rates of polymerization of quaternized analogs and the constant of chain transfer to the monomer and the activation energy of polymerization are close to the analogous characteristics of polymerization in the case of quaternized diallyldimethylammonium chloride. It is shown that for polymerization in bidistilled solution, the constant of chain transfer to the monomer (30°С, 3.8 × 10^–3) is more than three times lower than that for polymerization in monodistillate (30°С, 12.2 × 10^–3) and the ММ of the polymers is ~2.4 times higher than the ММ of the samples synthesized in monodistillate under the same conditions. It is ascertained that standard electrolyte admixtures in distilled aqueous solution considerably affect radical chemical reactions involving protonated forms.     

Diphilic Macromolecular Brushes with a Polyimide Backbone and Poly(methacrylic acid) Blocks in Side Chains

Novel macromolecular brushes with a polyimide backbone and diphilic diblock copolymer side chains consisting of a hydrophilic block of poly(methacrylic acid) adjacent to the backbone and the outer hydrophobic block of poly(methyl methacrylate) are synthesized. The synthesis includes the grafting of poly(tert-butyl methacrylate) to the polyimide chain followed by the polymerization of methyl methacrylate on the graft copolyimide as a branched multicenter macroinitiator. Brushes with diphilic side chains are obtained via the acidic hydrolysis of ester groups in the first block of side chains. The grafting polymerization of methacrylates is performed according to the “grafting from” approach by the method of pseudoliving atom transfer radical polymerization using two methodologies of polymerization activated by either copper- or iron-containing complexes. Conditions providing the controlled regime of the polymerization processes under study are found, and pathways for the targeted regulation of the degree of polymerization of methacrylate blocks and their grafting density are determined. As is shown by dynamic light scattering and transmission electron microscopy, the macromolecules of brushes with diphilic side chains form in ethanol homotypic, obviously spherical, supramolecular micellar structures with hydrodynamic radii in the range from 40 to 120 nm depending on the length and grafting density of the two blocks in diphilic side chains.     

Protonated member of poly(diallylammonium) family: Hydrodynamic and conformational properties

Secondary polyamine in protonated salt form – poly(diallylammonium trifluoro-acetate) is characterized as representative of polymer series based on N,N-diallyl-ammonium. Its hydrodynamic behavior in 1 M NaCl has been compared with the other series members – quaternary poly(diallyldimethylammonium chloride) and tertiary poly(diallylmethylammonium trifluoroacetate). It was shown that these polymers belong to semirigid class whose Kuhn segment length ～4?nm just slightly depends on chemical structure at high ionic strength. As specific for secondary polyamine, the sensitivity to proton equilibrium in solution and counter ion type was detected resulting in great difference of its Mark–Kuhn–Houwink equations from the quaternary analogue at the same conditions.     

Study of the187W states excited in the (n, γ) reaction

A singles-ray spectrum and a spectrum of summed amplitudes of coinciding pulses (SACP) were measured in the¹⁸⁶W(n, )¹⁸⁷W reaction experiment on the thermal neutron beam. It was for the first time that the data on¹⁸⁷W-transitions were obtained in the excitation energy region from 1500–2500 keV. The neutron binding energy was determined to beB _n=5467.25 (4) keV (statistical error only). In result the level scheme of¹⁸⁷W was developed in the excitation energy interval 1E _f < 3.4=" mev,=" which=" contained=" 105=" levels=" with=" about=" 70=" of=" them=" being=" identified=" for=" the=" first=" time.=" the=" experimental=" values=" for=" summed=" intensities=" of=" two-step=" cascades=" were=" established=" to=" exceed=" those=" predicted=" by=" the=" modern=" statistical=" theory=" (by=" 36±6%).=" this=" is=" explained=" by=" a=" considerable=" contribution=" of=" few-quasiparticle=" components=" to=" wave=" functions=" of=" compound=" and=" intermediate=">