- Ru-containing polyoxometalate fabricated on graphene oxide: Preparation, characterization and catalytic activity
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Polyoxometalates (POMs) with remarkable redox characteristics and good stability are considered as versatile catalysts, meanwhile graphene oxide (GO) with a layered structure and myriad oxygen atoms on its surface is also good catalyst. Thus their combination will have the synergistically enhanced effect on the catalytic performance and the reusability of the heterogeneous catalysts. Here, an environmentally-friendly heterogeneous catalyst (GO/PEI/RuPW10) was prepared by fabricating [(γ-PW10O36)2Ru4O5(OH)(H2O)4]9- (RuPW10) on the surface of GO functionalized by polyethylenimine (PEI). Further, this catalyst was applied to n-tetradecane oxidation using air as the oxidant. The results showed that 4.73% RuPW10 loaded catalyst exhibits high conversion (50.45%) of n-tetradecane under the optimized reaction condition. A recyclability test suggested that this catalyst can be reused up to five times without significant changes for the conversion of n-tetradecane. As a result, due to the high conversion, better stability and reusability, immobilizing POMs onto the surface of GO modified by PEI is one of the effective means to develop heterogeneous catalysts.
- Ma, Zhiyuan,Yu, Tian,Bi, Lihua
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- A new organo-ruthenium substituted tungstotellurate: Synthesis, structural characterization and catalytic properties
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Reaction of [RuC6H6Cl2]2 with TeO2 and Na2WO4·2H2O in aqueous solution (pH 4.7) yielded a novel organo-ruthenium supported tungstotellurate polyanion, [Te2W20O70(RuC6H6)2]8- (Ru-1), which is composed of two [RuC6H6]2+ units linked to a [Te2W20O70]12- fragment through Ru-O(W) bonds resulting in an assembly with idealized C2h symmetry. Furthermore, the polyanion Ru-1 was anchored on 3-aminopropyltriethoxysilane (apts)-modified SBA-15 to prepare new catalysts (SBA-15-apts-Ru-1) containing different amounts of Ru-1, which were characterized using powder X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), N2-adsorption measurement and Fourier transform infrared reflectance (FT-IR) spectroscopy. Finally, the catalytic activity of SBA-15-apts-Ru-1 was evaluated for the aerobic oxidation of n-tetradecane using air as the oxidant in the absence of any additives or solvents. In addition, the optimum catalytic reaction conditions were also determined.
- Zheng, Da-Ming,Wang, Rui-Qiang,Du, Yu,Hou, Guang-Feng,Wu, Li-Xin,Bi, Li-Hua
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p. 8829 - 8836
(2016/10/11)
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- Stoichiometric reactions of acylnickel(II) complexes with electrophiles and the catalytic synthesis of ketones
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Acylnickel(II) complexes feature prominently in cross-electrophile coupling (XEC) reactions that form ketones, yet their reactivity has not been systematically investigated. We present here our studies on the reactivity of acylnickel(II) complexes with a series of carbon electrophiles. Bromobenzene, α-chloroethylbenzene, bromooctane, and iodooctane were reacted with (dtbbpy)NiII(C(O)C5H11)(Br) (1b) and (dtbbpy)NiII(C(O)tolyl)(Br) (1c) to form a variety of organic products. While reactions with bromobenzene formed complex mixtures of ketones, reactions with α-chloroethylbenzene were highly selective for the cross-ketone product. Reactions with iodooctane and bromooctane also produced the cross-ketone product, but in intermediate yield and selectivity. In most cases the presence or absence of a chemical reductant (zinc) had only a small effect on the selectivity of the reaction. The coupling of 1c with iodooctane (60% yield) was translated into a catalytic reaction, the carbonylative coupling of bromoarenes with primary bromoalkanes (six examples, 60% average yield).
- Wotal, Alexander C.,Ribson, Ryan D.,Weix, Daniel J.
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supporting information
p. 5874 - 5881
(2015/01/09)
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- Reaction of unstabilized iodonium ylides with organoboranes
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Exposure of monocarbonyl iodonium ylides, generated by the ester exchange of (Z)-(2-acetoxyvinyl)-λ3-iodanes with EtOLi, to organoboranes results in a 1,2-shift of a carbon ligand from boron to the ylide carbons, which probably generates hitherto uncharacterized α-boryl ketones.
- Ochiai, Masahito,Tuchimoto, Yoshimi,Higashiura, Nobuyuki
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p. 1505 - 1508
(2007/10/03)
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- Facile synthesis of ketones from 1,1-disilylethenes via oxidation of gem-disilylalkanes
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The oxidation of gem-disilylalkanes, which can be derived from 1,1-disilylethene, alkyllithiums and alkyl halides, affords the corresponding ketones.
- Inoue, Atsushi,Kondo, Junichi,Shinokubo, Hiroshi,Oshima, Koichiro
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p. 114 - 115
(2007/10/03)
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- Convenient Synthesis of Functionalized Dialkyl Ketones and Alkanoylsilanes: 1-(Benzotriazol-1-yl)-1-phenoxyalkanes as Alkanoyl Anion Equivalents
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(Benzotriazol-1-yl)-1-phenoxyalkanes 10, prepared by two-step transformations of the corresponding aldehydes, are readily deprotonated at the methine group by BuLi.Subsequent reactions with alkyl halides, aldehydes, ketones, and imines yield the corresponding substituted derivatives that undergo hydrolysis under acidic conditions to afford the expected functionalized ketones 13, 15, 17, 19, 21, 24 and 25.Two successive lithiations of (benzotriazolyl)phenoxymethane, each followed by reaction with a trialkylsilyl chloride, alkyl halide, aldehyde, or ketone, generate similar intermediates 27, 39, 31, 33, and 36.Subsequent hydrolyses of 27, 29, 31, 33, and 36 yield the functionalized ketones 28, 30, and 32 and the alkanoylsilanes 34 and 37 in good yields.
- Katritzky, Alan R.,Lang, Hengyuan,Wang, Zuoquan,Lie, Zhu
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p. 7551 - 7557
(2007/10/03)
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- Hyperfine Structures of Doxyl-Labeled n-Alkyl Chains by NMR and EPR
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The proton hyperfine coupling constants in a series of n-alkyl chains with a doxyl group attached at various points from the end of the chain have been measured by NMR and EPR spectroscopies.The hyperfine structure shows no further change when the attachment point is four or more carbon-carbon bonds from the end of the chain.The high resolution afforded by 500 MHz NMR reveals small magnetic inequivalencies in the chain methylene hyperfine coupling constants located at the same distance from the attachment point.Protons in the same chain methylene group are shown to have different hyperfine coupling constants while protons on different chain methylene groups, symmetrically placed with respect to attachment point, are the same, in every case except one.EPR spectra simulated from hyperfine coupling constants derived from NMR are in excellent agreement with experiment.Inhomogeneous EPR line broadening is found to be in excellent agreement with a previously derived universal hyperfine pattern (B.L.Bales, in "Biological Magnetic Resonance" (L.J.Berliner and J.Reuben, Eds.), Vol. 8, p. 77, Plenum, New York, 1989), so no new correction procedures are necessary.Strategies for selectively deuterating n-alkyl spin probes are developed and compared with some results taken from the literature.Deuterating the chain methylene groups two to three carbon-carbon bonds from the attachment point is necessary for the maximum gain in resolution and sensitivity.
- Bales, Barney L.,Mareno, Donna,Harris, Francis L.
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- NOVEL SYNTHESIS OF INTERNAL ALKENYLDIALKYLBORANE BY THE REACTION OF 1-HALO-1-ALKENYLDIALKYLBORANE WITH GRIGNARD REAGENT.
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To synthesize internal alkenyldialkylboranes, coupling reactions were carried out by using 1-halo-1-alkenyldialkylboranes and Grignard reagents. Hydrogen peroxide oxidation and protonolysis with acetic acid of the reaction product revealed that internal (E)-alkenyldialkylborane was formed in 60-90% yield.
- Arase,Hoshi,Masuda
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p. 209 - 213
(2007/10/02)
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- Oxidation of sec-Alcohols to the Corresponding Ketones by Corynebacterium equi
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Corinebacterium equi IFO 3730 was found to oxidize a wide variety of sec-alcohols, including alkanols, substituted alkanols, alkenols and cyclic alcohols, in moderate to high yields.Among them, the sec-alcohols which have longer carbon chains were oxidized more smoothly than those with smaller numbers of carbon.Although both enantiomers of unsymmetrically disubstituted carbinols were oxidized, the S form of 2-dodecanol was converted to the corresponding ketone a little faster than the other enantiomer.
- Ohta, Hiromichi,Fujiwara, Hidenori,Tsuchihashi, Gen-ichi
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p. 1509 - 1516
(2007/10/02)
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- Microbial Oxidation of sec-Alcohols to Ketones
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Corynebacterium equi IFO 3730, which had previously been demonstrated to be capable of assimilating 1-hexadecene, also showed good growth on 1-hexadecen-11-ol (1a).The corresponding ketone, 1-hexadecen-11-one (2a) was isolated as the product from the broth.This microorganism-mediated oxidation has been revealed to have a wide applicability, and a variety of sec-alcohols were oxidized to the corresponding ketones in good yields on incubation with the bacterium growh on 1-hexadecene as a sole source of carbon.
- Ohta, Hiromichi,Senuma, Satoru,Tetsukawa, Hatsuki
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p. 579 - 584
(2007/10/02)
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