نتایج جستجو برای: epoxidation of alkenes
تعداد نتایج: 21164396 فیلتر نتایج به سال:
A new hexaprismane Co(II)6(μ3-OH)6 cluster-based three-dimensional coordination polymer ({Co(μ3-OH)(HCOO)0.72(CH3COO)0.28}n, Co6-CP) was successfully synthesized and characterized with single-crystal XRD, IR spectra, TGA spectra and elemental analysis. Co6-CP was used as an effective heterogeneous catalyst for the aerobic epoxidation of various alkenes. For the catalytic epoxidation of trans-st...
Cobaltabis(dicarbollide), Na[3,3?-Co(?5-1,2-C2B9H11)2] Na[1]), is an efficient photoredox catalyst for the epoxidation of alkenes in water, at low loading and requiring short reaction times (15–30 min).
Benign Method for Alkene Epoxidations Benjamin S. Lane and Kevin Burgess* Department of Chemistry, Texas A & M UniVersity PO Box 30012, College Station, Texas 77842-3012 ReceiVed NoVember 17, 2000 This paper reports a simple method wherein manganese (2+) salts, for example, MnSO4, catalyze epoxidation of alkenes using 30% aqueous hydrogen peroxide as the terminal oxidant. The reactions are perf...
A magnetically recoverable catalyst consisting of Mn (III) salophen complex was prepared. The synthesized catalyst was characterized by X-ray powder diffraction (XRD), transmission electron microscopy (TEM), vibrating sample magnetometry (VSM), inductively coupled plasma atomic emission spectroscopy (ICP-AES) and Fourier transform infrared (FT-IR). The immobilized catalyst was shown to be an ef...
Several toluene monooxygenase-producing organisms were tested for their ability to oxidize linear alkenes and chloroalkenes three to eight carbons long. Each of the wild-type organisms degraded all of the alkenes that were tested. Epoxides were produced during the oxidation of butene, butadiene, and pentene but not hexene or octadiene. A strain of Escherichia coli expressing the cloned toluene-...
Through catalytic epoxidation and aziridination of olefins versatile synthetic intermediates and subunits of biologically active compounds and pharmaceuticals –epoxides and aziridines– can be obtained. The focus of this review is on recent advances in the epoxidation and aziridination of challenging terminal alkenes with respect to safety of solvents or reagents used and atom economy aspects, a...
The epoxidation of alkenes was carried out over a CuO/Al(2)O(3) catalyst using cumene as an oxygen carrier, through a one-pot reaction, giving high conversion and selectivity with different substrates. Trans-β-methylstyrene gave the corresponding epoxide in 95% yield after 3 h.
A practical method for the multigram scale selective cis-dihydroxylation of electron deficient alkenes such as diethyl fumarate and N-alkyl and N-aryl-maleimides using H(2)O(2) is described. High turnovers (>1000) can be achieved with this efficient manganese based catalyst system, prepared in situ from a manganese salt, pyridine-2-carboxylic acid, a ketone and a base, under ambient conditions....
Using low-temperature trapping experiments with 1 ,l-diphenyl-2-picrylhydrazine moni tored by UV/Vis spectroscopy, it is shown that the rate-determining step in the epoxidation of alkenes by hypochlorite, catalysed by manganese(III) porphyrins, involves the formation of the active oxo-manganese species [(P)MnO]+.
Catalytic epoxidation by perrhenate through the formation of organic-phase supramolecular ion pairs.
Organic-phase supramolecular ion pair (SIP) host-guest assemblies of perrhenate anions (ReO4(-)) with ammonium amide receptor cations are reported. These compounds act as catalysts for the epoxidation of alkenes by aqueous hydrogen peroxide under biphasic conditions and can be recycled several times with no loss in activity.
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