Reduction of Hg(II) salts in aqueous acidic solutions by SO2

Kinetic studies of the reduction of Hg(II) salts in aqueous acidic solutions by SO₂ in mild conditions have revealed that SO₂ quantitatively reduces Hg(II) to metal in the examined HClO₄ concentration range (2–8M^–1).

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Hg(II) . , HClO₄ (2–8 .^–1) SO₂ Hg(II) .

     

Convenient synthesis of 5′-methyl-2′-desoxyuridines

A convenient method has been developed for the synthesis of 5-methyl-2-desoxyuridines. Chlorination of 5-O-benzoyl-5-methyluridines with a mixture of Ph₃P and CCl₄ in DMF affords the 2-desoxy-2-chloro-derivatives, which are then reduced with tributyltin hydride. The crystalline 5-O-benzoyl-5-methyl-2-desoxyuridines were obtained in overall yields of 40–60%. In a similar way, 5-O-benzoyluridine has given 5-O-benzoyl-2-desoxyuridine.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 2, pp. 246–248, February, 1989.     

The influence of the molecular weight of DMC polyethers on the physical-mechanical properties of PU materials based on them

This article describes synthesis of polyurethane (PU) elastomers based on DMC polyethers. The influence of the molecular weight of DMC polyethers on the strength characteristics and mechanical hysteresis of model PU composites based on them is studied. It is shown that, when the molecular weight of DMC polyethers changes in the range of 2000–4000, the strength of PU materials dramatically increases, while a considerable improvement of elastic properties is observed when using polyethers with MW = 8.000 or higher.     

Spectra of Protons and Alpha Particles and Their Comparison in the NUCLEON Experiment Data

JETP Letters - The aim of the NUCLEON space experiment was to measure spectra of high-energy cosmic rays. Direct measurements of energy spectra of protons and nuclei of cosmic rays which allow...     

Composite Pd/Pr4O7/C catalysts: Synthesis, dispersity and properties

The catalysts prepared sequentiallyvia the interaction of C₃H₅PdC₅H₅ with the surface of evacuated Pr₄O₇/C and reduction with H₂ at 573 K, contain 20–30 Pd particles and Pr₄O₇ particles<20 . The catalysts obtained have two-order of magnitude higher specific activity in the CH₃OH synthesis than Pd/C.     

Light Neutral Clusters in Supernova Matter

Physics of Atomic Nuclei - The role of weakly bound neutral clusters, such as dineutrons and tetraneutrons, in matter of high density and high temperature is discussed. Under such conditions, which...     

Nondestructive Control of the Surface,Layers, and Charge Carrier Concentration on SiC Substrates and Structures

Technical Physics - Silicon carbide substrates and epitaxial structures are investigated by nondestructive contactless methods. Parameters of the disrupted surface layer and roughnesses are...     

New 3,4-bis(indol-1-yl)maleimides as protein kinase inhibitors

Chemistry of Heterocyclic Compounds - Several previously unknown derivatives of 3,4-bis(indol-1-yl)maleimide, as well as 3-(2,3-dihydroindol-1-yl)-4-(indol-1-yl)maleimide were synthesized as...     

Formation of Free Electrons in Collisions of Xe Atoms with α Particles

Technical Physics - We have measured the cross sections of elementary processes occurring during collisions of impinging 3He2+ particles with kinetic energies in the range 1–100 keV with Xe...     

The number of periodic solutions of polynomial differential equations

We estimate the number of periodic solutions for special classes ofnth-order ordinary differential equations with variable coefficients. Translated fromMatematicheskie Zametki, Vol. 64, No. 5, pp. 720–727, November, 1998. The author thanks Yu. S. Il'yashenko for setting the problems, permanent advice, and overall support. The author is also thankful to D. A. Panov for numerous discussions. This research was supported by the CRDF Foundation under grant MR1-220, by the INTAS Foundation under grant No. 93-05-07, and by the Russian Foundation for Basic Research under grant No. 95-01-01258.