The Experts below are selected from a list of 303 Experts worldwide ranked by ideXlab platform
Changqing Wang - One of the best experts on this subject based on the ideXlab platform.
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solvent free one pot synthesis of α β unsaturated esters in the presence of a c3 symmetric Arsine
ChemInform, 2016Co-Authors: Changqing Wang, Rong Zhou, Liu Yang, Guangquan MeiAbstract:ABSTRACTAn efficient synthesis of α, β-unsaturated esters is achieved via a one-pot reaction in the presence of a C3-symmetric Arsine. The key advantages are the short reaction time, simple workup, mild reaction conditions, and high yields.
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highly stereoselective cyclopropanation of olefins catalyzed by a novel c 3 symmetric Arsine
Synthetic Communications, 2014Co-Authors: Changqing Wang, Daoan Xiao, Rong Zhou, Hui Liang, Guangquan MeiAbstract:Abstract A novel C 3-symmetric Arsine was employed in the one-pot cyclopropanation of olefins with carbonyl-stabilized arsonium ylides formed in situ from phenacyl bromide in the presence of NaHCO3. This new Arsine demonstrates good stereoselectivity and activity in the one-pot cyclopropanation of arylidenemalononitrile. [Supplementary materials are available for this article. Go to the publisher's online edition of Synthetic Communications® for the following free supplemental resource(s): Full experimental and spectral details.]
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synthesis of a novel c3 symmetric Arsine and its application in stereoselective cyclopropanation of electron deficient olefins
Tetrahedron Letters, 2012Co-Authors: Changqing WangAbstract:Abstract A novel C3-symmetric Arsine was synthesized from p-arsanilic acid in three steps. It was employed in the one-pot cyclopropanation of olefins with carbonyl-stabilized arsonium ylides formed in situ from methyl bromoacetate in the presence of NaHCO3. This new Arsine demonstrates good stereoselectivity and activity in the one-pot cyclopropanation of arylidenemalononitrile.
Caisheng Song - One of the best experts on this subject based on the ideXlab platform.
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synthesis of silica supported bidentate Arsine palladium complex and its catalytic properties for amidation butoxycarbonylation of aryl halides
Journal of Molecular Catalysis A-chemical, 2004Co-Authors: Mingzhong Cai, Yizheng Huang, Caisheng SongAbstract:A silica-supported bidentate Arsine palladium complex has been prepared from 4-oxa-6,7-dichloroheptyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide in THF and then the reaction with palladium chloride. This polymeric Arsine palladium complex is an efficient catalyst for Heck carbonylation of aryl iodides and activated aryl bromides under atmospheric pressure of carbon monoxide and can be recovered and reused.
Mingzhong Cai - One of the best experts on this subject based on the ideXlab platform.
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Novel stereoselective synthesis of (E)-cinnamonitriles via Heck arylation of acrylonitrile catalysed by a silica-supported bidentate Arsine palladium(0) complex:
Journal of Chemical Research, 2004Co-Authors: Mingzhong Cai, Xiaokai Tong, Junmin Chen, Yizheng HuangAbstract:(E)-Cinnamonitriles have been synthesised stereoselectively in high yields via Heck arylation of acrylonitrile with aryl iodides catalysed by a silica-supported bidentate Arsine palladium(0) comple...
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synthesis of silica supported bidentate Arsine palladium complex and its catalytic properties for amidation butoxycarbonylation of aryl halides
Journal of Molecular Catalysis A-chemical, 2004Co-Authors: Mingzhong Cai, Yizheng Huang, Caisheng SongAbstract:A silica-supported bidentate Arsine palladium complex has been prepared from 4-oxa-6,7-dichloroheptyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide in THF and then the reaction with palladium chloride. This polymeric Arsine palladium complex is an efficient catalyst for Heck carbonylation of aryl iodides and activated aryl bromides under atmospheric pressure of carbon monoxide and can be recovered and reused.
Yizheng Huang - One of the best experts on this subject based on the ideXlab platform.
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Novel stereoselective synthesis of (E)-cinnamonitriles via Heck arylation of acrylonitrile catalysed by a silica-supported bidentate Arsine palladium(0) complex:
Journal of Chemical Research, 2004Co-Authors: Mingzhong Cai, Xiaokai Tong, Junmin Chen, Yizheng HuangAbstract:(E)-Cinnamonitriles have been synthesised stereoselectively in high yields via Heck arylation of acrylonitrile with aryl iodides catalysed by a silica-supported bidentate Arsine palladium(0) comple...
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synthesis of silica supported bidentate Arsine palladium complex and its catalytic properties for amidation butoxycarbonylation of aryl halides
Journal of Molecular Catalysis A-chemical, 2004Co-Authors: Mingzhong Cai, Yizheng Huang, Caisheng SongAbstract:A silica-supported bidentate Arsine palladium complex has been prepared from 4-oxa-6,7-dichloroheptyltriethoxysilane via immobilization on fumed silica, followed by reacting with potassium diphenylarsenide in THF and then the reaction with palladium chloride. This polymeric Arsine palladium complex is an efficient catalyst for Heck carbonylation of aryl iodides and activated aryl bromides under atmospheric pressure of carbon monoxide and can be recovered and reused.
Bernard Allen Toseland - One of the best experts on this subject based on the ideXlab platform.
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removal of Arsine from synthesis gas using a copper on carbon adsorbent
Industrial & Engineering Chemistry Research, 2006Co-Authors: Robert Quinn, Thomas A Dahl, Barry W Diamond, Bernard Allen ToselandAbstract:A variety of supported metal and metal oxide adsorbents were evaluated for removal of Arsine (AsH3) from synthesis gas (syngas), a mixture primarily of carbon monoxide and hydrogen. A copper(II) oxide (CuO)/carbon adsorbent was judged to be most promising and examined more thoroughly. Exposure of the CuO/carbon adsorbent to syngas at 750 psig resulted in only a modest increase in bed temperature. No evidence that the adsorbent acted as a methanol synthesis catalyst or promoted other syngas chemistry was observed. It was found, however, that even at modest temperatures (30−40 °C) some reduction to metallic copper (Cu) occurred. The exothermic reduction of CuO presented a significant operational concern, and use of the adsorbent required a controlled reduction to Cu/carbon prior to exposure to syngas. The Arsine affinity of CuO/carbon was very high with a minimum capacity of 3.0 wt % arsenic for a syngas feed containing 420 ppbv. The reduced adsorbent, Cu/carbon, was less effective for AsH3 removal, and at ...
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the role of Arsine in the deactivation of methanol synthesis catalysts
Applied Catalysis A-general, 2004Co-Authors: Robert Quinn, T Mebrahtu, Thomas A Dahl, F A Lucrezi, Bernard Allen ToselandAbstract:Abstract The liquid phase methanol (LPMEOH™) process is successfully producing methanol from coal-derived synthesis gas on an industrial scale. This process uses a standard copper, zinc oxide, and alumina catalyst suspended in an inert mineral oil in a slurry bubble column reactor. An arsenic-containing species, most reasonably Arsine, was found in the feed to the LPMEOH™ commercial demonstration facility located at Eastman Chemical Company’s chemicals-from-coal complex in Kingsport, TN. Laboratory testing showed that Arsine is, in fact, a powerful methanol synthesis catalyst poison. At levels as low as 150 ppbv, Arsine results in a rapid deactivation of the catalyst. Removal of Arsine results in a deactivation rate consistent with a clean synthesis gas feed; that is, Arsine poisoning stops when it is removed from the feed. We infer that Arsine reacts irreversibly with the catalyst under the methanol synthesis conditions. X-ray absorption spectroscopy (XAS) of arsenic-containing used catalyst indicated the presence of zero-valent arsenic in an intermetallic surface phase that is structurally related to Domeykite (Cu 3 As). Experimental evidence, thermodynamics, and literature relating to other metal–Arsine chemistry were consistent with dissociative adsorption of Arsine on the copper surface to form gaseous H 2 and Cu 3 As. To deal with Arsine poisoning, we have developed adsorption technology that can remove Arsine to levels low enough that catalyst performance is unaffected.