Kinetics of Addition of Alcohols to 3-Aroyl-2,4-dihydro-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones

The kinetics of the reaction of 3-aroyl-2,4-dihydro-1H-pyrrolo[2,1-c][1,4]benzoxazine-1,2,4-triones with aliphatic alcohols in toluene at 25°C were studied by spectrophotometry. The effects of electronic and steric factors in the nucleophile and substrate were estimated by treatment of the kinetic results by the Hammett and Taft equations.     

Phase formation in the Ni2+-WO 42? -H+-H2O system (Z = 1.00). Crystal structure and properties of sodium heteropolyhexatunsten nickelate(2+) Na4[Ni(OH)6W6O18]·16H2O

The green crystals of Ni_1.5H[Ni(OH)₆W₆O₁₈]·12.5H₂O and blue crystals of Na₄[Ni(OH)₆W₆O₁₈]·16H₂O were isolated from the acidified (to Z = ν(H⁺)/ν(WO₄²⁻) = 1.00) solutions of Ni(NO₃)₂-Na₂WO₄-HNO₃-H₂O systems. The synthesized salts were identified by chemical analysis, XRPA, and IR spectroscopy. It was shown that the heteropolyanions belonged to the Anderson-Evans type of structure. An X-ray diffraction study of Na₄[Ni(OH)₆W₆O₁₈]·16H₂O was carried out (M _r = 1932.07, triclinic, space group P-1, a = 8.0089(11) ?, b = 10.5758(14) ?, c = 12.1987(16) ?; α = 69.268(13)°, β = 71.069(12)°, γ = 83.816(11)°; V = 914.0(2) ?³ at T = 293 K, Z = 1, ρ_cal = 3.510 g/cm³, F ₀₀₀ = 874, μ = 19.470 mm⁻¹, −16 ≤ h ≤ 16, −21 ≤ k ≤ 21, −24 ≤ l ≤ 24; the final R factors are R _F = 0.0277, wR ² = 0.0469 for the observed reflections (R _F = 0.0606, wR ² = 0.0523 for all independent reflections); S = 0.953; CSD-419883). The structure was solved by direct methods and refined in an anisotropic approximation. Hydrogen atoms were found in a difference synthesis and refined in an isotropic approximation with geometrical limitations. The nature of water in Na₄[Ni(OH)₆W₆O₁₈]·16H₂O was characterized by DTA. XRPA was used to identify the thermolysis products of heteropoly compounds. Original Russian Text Copyright ? 2009 by G. M. Rozantsev, S. V. Radio, N. I. Gumerova, V. N. Baumer, and O. B. Shishkin __________ Translated from Zhurnal Strukturnoi Khimii, Vol. 50, No. 2, pp. 311–319, March–April, 2009.     

Oxidation and Stabilization of Dioxane Alcohol Formals

The kinetic parameters of liquid-phase oxidation of dioxane alcohol formals were determined. The inhibiting activity of a number of phenol and organophosphorus antioxidants is evaluated and methods are proposed for decelerating the destruction of dioxane alcohol formals, occurring via thermal oxidation.     

Synthesis and crystal structure of hydrogen strontium paratungstate Sr<Subscript>4.5</Subscript>H[W<Subscript>12</Subscript>O<Subscript>40</Subscript>(OH)<Subscript>2</Subscript>] · 30H<Subscript>2</Subscript>O

The conditions for formation of individual isopolytungstates in solutions of the Sr(NO₃)₂-Na₂WO₄-HNO₃-H₂O system acidified to Z = ν(H⁺)/ν(WO ₄ ^2? ) = 1.29 were studied. The conditions of formation of strontium paratungstate B, strontium hydroheptatungstate, and hydrogen strontium paratungstate were determined. An X-ray diffraction study of single crystals of Sr_4.5H[W₁₂O₄₀(OH)₂] · 30H₂O was carried out. Selected crystallographic data for H₆₃O₇₂Sr_4.50W₁₂ are: M _r = 3815.99, monoclinic, space group P2₁/c, a = 11.41270(10) Å, b = 23.7575(3) Å, c = 12.4392(2) Å, β = 110.476(2)°, V = 3159.64(7) ų at T = 293 K, Z = 2, ρ = 4.011 g/cm³, F₀₀₀ = 3396, μ(MoK _α) = 25.635 mm^?1, ?14 ≤ h ≤ 14, ?30 ≤ k ≤ 30, ?16 ≤ l ≤ 16, R _F = 0.0430, wR ² = 0.1067 (R _F = 0.0506, wR ² = 0.1129), and S = 1.043.     

Heteronuclear coordination compounds of copper and cobalt in urethane-yielding reactions

Heteronuclear coordination compounds capable of catalyzing the low-temperature dissociation of urethane groups were synthesized on the basis of copper and cobalt chlorides. The study was performed with an urethane prepolymer produced from oligoester diol and 2,4-toluylene diisocyanate. It was found that the dissociation of urethane groups in the prepolymer is accompanied by formation of carbodiimides and release of 2,4-toluylene diisocyanate. As a result of the subsequent redox interaction, Cu(II) ions are mostly converted to Cu(I), and the involvement of isocyanate groups in the para-position into the reaction processes leads to formation of azoaromatic derivatives. It is shown that their coordination binding by Co(II) ions strongly affects both the supramolecular organization of polyurethanes and a set of their physicomechanical properties.     

A peroxide that contains furan and acetal fragments

2-Methyl-2-tetrahydrofuryl(1,1-diethoxy-1-ethyl) peroxide (III) was obtained from 1,1-diethoxyethane hydroperoxide (II) and 2-methyl-4,5-dihydrofuran (I). The initiating ability of the product obtained was determined.Translated from Khimiya Geterotsiklicheskikh Soedinenii, No. 4, pp. 458–460, April, 1985.