17257-80-6Relevant articles and documents
Crystal Structure and Catalytic Behavior in Olefin Epoxidation of a One-Dimensional Tungsten Oxide/Bipyridine Hybrid
Amarante, Tatiana R.,Antunes, Margarida M.,Valente, Anabela A.,Paz, Filipe A. Almeida,Pillinger, Martyn,Gon?alves, Isabel S.
, p. 9690 - 9703 (2015/11/03)
The tungsten oxide/2,2′-bipyridine hybrid material [WO3(2,2′-bpy)]·nH2O (n = 1-2) (1) has been prepared in near quantitative yield by the reaction of H2WO4, 2,2′-bpy, and H2O in the mole ratio of ca. 1:2:700 at 160°C for 98 h in a rotating Teflon-lined digestion bomb. The solid-state structure of 1 was solved and refined through Rietveld analysis of high-resolution synchrotron X-ray diffraction data collected for the microcrystalline powder. The material, crystallizing in the orthorhombic space group Iba2, is composed of a one-dimensional organic-inorganic hybrid polymer, ∞1[WO3(2,2′-bpy)], topologically identical to that found in the previously reported anhydrous phases [MO3(2,2′-bpy)] (M = Mo, W). While in the latter the N,N′-chelated 2,2′-bpy ligands of adjacent corner-shared {MO4N2} octahedra are positioned on the same side of the 1D chain, in 1 the 2,2′-bpy ligands alternate above and below the chain. The catalytic behavior of compound 1 for the epoxidation of cis-cyclooctene was compared with that for several other tungsten- or molybdenum-based (pre)catalysts, including the hybrid polymer [MoO3(2,2′-bpy)]. While the latter exhibits superior performance when tert-butyl hydroperoxide (TBHP) is used as the oxidant, compound 1 is superior when aqueous hydrogen peroxide is used, allowing near-quantitative conversion of the olefin to the epoxide. With H2O2, compounds 1 and [MoO3(2,2′-bpy)] act as sources of soluble active species, namely, the oxodiperoxo complex [MO(O2)2(2,2′-bpy)], which is formed in situ. Compounds 1 and [WO(O2)2(2,2′-bpy)] (2) were further tested in the epoxidation of cyclododecene, trans-2-octene, 1-octene, (R)-limonene, and styrene. The structure of 2 was determined by single-crystal X-ray diffraction and found to be isotypical with the molybdenum analogue.
Epoxidation of electron-deficient αβ-unsatured carbonyl compounds over Keggin heteropoly compounds with acqueous H2O 2
Gao, Qiang,Ding, Yong,Liu, Haitao,Suo, Jishuan
, p. 716 - 718 (2007/10/03)
The epoxidation of a variety of electron-deficient α,β- unsaturated carbonyl compounds has been studied using a series of heteropoly compounds and aqueous hydrogen peroxide in acetonitrile. Among the heteropoly compounds investigated, (CTP)3VMo12O40 showed the highest catalytic performance for the epoxidation of these compounds.
A Novel Oxidation of Internal Alkynes with Hydrogen Peroxide Catalyzed by Peroxotungsten Compounds
Ishii, Yasutaka,Sakata, Yasuyuki
, p. 5545 - 5547 (2007/10/02)
Internal alkynes underwent a novel oxidation with aqueous hydrogen peroxide catalyzed by peroxotungsten compounds under two-phase conditions using chloroform as the solvent, giving α,β-epoxy ketones and α,β-unsaturated ketones as principal products.The epoxidation of α,β-unsaturated ketones by this catalyst-oxidant system appeared to involve the electrophilic attack of the peroxo species to the double bond.
