Two novel PNP ligands have been synthesized and characterized by 1H-NMR, elemen- tal analysis, and mass spectra. In combination with Cr(Ⅲ ) and cocatalyst MAO, they generate active catalytic systems that tetramerize ...Two novel PNP ligands have been synthesized and characterized by 1H-NMR, elemen- tal analysis, and mass spectra. In combination with Cr(Ⅲ ) and cocatalyst MAO, they generate active catalytic systems that tetramerize ethylene with both high catalytic activity and high selectivity to produce 1-octene. The results show that these catalyst sys- tems are able to catalyze ethylene tetramerization, with high catalytic activity up to 0.89×106 g/mol Cr.h, and the selectivity of C8 in products is 72.52%, and the percentage of 1-olefins in the C8 cut is 97.87%.展开更多
The synthesis and characterization of a novel trinuclear diphosphinoamine ligand 2 are reported. The ligand combined with Cr(III), activated with methylaluminoxane, lead to highly active and long-lifetime catalytic sy...The synthesis and characterization of a novel trinuclear diphosphinoamine ligand 2 are reported. The ligand combined with Cr(III), activated with methylaluminoxane, lead to highly active and long-lifetime catalytic systems for the tetramerization of ethylene to form 1-octene. The effects of reaction temperature, reaction pressure, molar ratio of Al/Cr and bis(diphenylphosphino)amine/Cr on the catalytic activity and product selectivity were studied. Compared with its mononuclear analogue 1, ligand 2 showed a higher catalytic activity and longer lifetime for ethylene tetramerization in the presence of methylaluminoxane as cocatalyst. High molecular weight polyethylene was generated as a by-product with extremely broad molecular weight distributions.展开更多
A novel triple-site diphosphinoamine (PNP) ligand was synthesized and characterized. In combination with Cr(III) and methylaluminoxane (MAO), it generated active catalytic systems for ethylene tetramerization toward 1...A novel triple-site diphosphinoamine (PNP) ligand was synthesized and characterized. In combination with Cr(III) and methylaluminoxane (MAO), it generated active catalytic systems for ethylene tetramerization toward 1-octene with high catalytic activity and long lifetime. The effects of reaction temperature, molar ratio of Al/Cr and molar ratio of ligand/Cr on catalytic activity and selectivity to 1-octene were studied with reaction kinetics of the catalytic system for ethylene tetramerization described. At the Al/Cr molar ratio of 100, the catalytic activity is up to 2.29×106 g·mol-1 (Cr)·h-1 and the selectivity to 1-octene is 49.65 wt%.展开更多
TiO2 nanotubes supported amorphous Co-B（Co-B/TNTs） catalyst was prepared via impregnation- chemical reduction procedure. The catalyst was characterized with transmission electron microscopy（TEM）, ammonia temperatu...TiO2 nanotubes supported amorphous Co-B（Co-B/TNTs） catalyst was prepared via impregnation- chemical reduction procedure. The catalyst was characterized with transmission electron microscopy（TEM）, ammonia temperature-programmed desorption（NH3-TPD）, thermogravimetry-differential thermal analysis（TG-DTA）, Fourier transform infrared spectroscopy（FTIR） and Raman spectroscopy. The effects of temperature and ratio of CO to HE on the hydroformylation of 1-octene were studied. At an optimized reaction temperature（150 ℃） and volume ratio of CO to H2（2：1）, the conversion of 1-octene can reach 97.4% with a selectivity of 23.1% for total aldehydes and n/i-aldehyde molar ratio of 40：60. To obtain higher selectivity for linear aldehydes, Co-B/TNTs modified with triphenylphosphine for the hydroformylation of 1-octene were investigated. When molar ratio of P/Co was 4, the yield of total aldehydes was the highest（31.6%） with a good selectivity for linear product（n/i-aldehyde molar ratio was 70：30）. In recycle use, the Co-B/TNTs catalyst modified with triphenylphosphine could be reused five times without reducing the activity and selectivity obviously. For a comparative study, all the Co-B/TNTs to catalyze the hydroformylation of other olefins exhibited high conversion under the optimized conditions.展开更多
文摘Two novel PNP ligands have been synthesized and characterized by 1H-NMR, elemen- tal analysis, and mass spectra. In combination with Cr(Ⅲ ) and cocatalyst MAO, they generate active catalytic systems that tetramerize ethylene with both high catalytic activity and high selectivity to produce 1-octene. The results show that these catalyst sys- tems are able to catalyze ethylene tetramerization, with high catalytic activity up to 0.89×106 g/mol Cr.h, and the selectivity of C8 in products is 72.52%, and the percentage of 1-olefins in the C8 cut is 97.87%.
基金supported by the National Natural Science Foundation of China (U1162114)the Program for New Century Excellent Talents in University+1 种基金the Program for New Century Excellent Talents in Heilongjiang Provincial University(NCET-06-010)the Science Foundation of Tianjin University of Science & Technology (20090420)
文摘The synthesis and characterization of a novel trinuclear diphosphinoamine ligand 2 are reported. The ligand combined with Cr(III), activated with methylaluminoxane, lead to highly active and long-lifetime catalytic systems for the tetramerization of ethylene to form 1-octene. The effects of reaction temperature, reaction pressure, molar ratio of Al/Cr and bis(diphenylphosphino)amine/Cr on the catalytic activity and product selectivity were studied. Compared with its mononuclear analogue 1, ligand 2 showed a higher catalytic activity and longer lifetime for ethylene tetramerization in the presence of methylaluminoxane as cocatalyst. High molecular weight polyethylene was generated as a by-product with extremely broad molecular weight distributions.
基金the Program for New Century Excellent Talents in University (NCET)the Program for New Century Excellent Talents in Heilongjiang Provincial Universities (Grant No. NCET-06-010)
文摘A novel triple-site diphosphinoamine (PNP) ligand was synthesized and characterized. In combination with Cr(III) and methylaluminoxane (MAO), it generated active catalytic systems for ethylene tetramerization toward 1-octene with high catalytic activity and long lifetime. The effects of reaction temperature, molar ratio of Al/Cr and molar ratio of ligand/Cr on catalytic activity and selectivity to 1-octene were studied with reaction kinetics of the catalytic system for ethylene tetramerization described. At the Al/Cr molar ratio of 100, the catalytic activity is up to 2.29×106 g·mol-1 (Cr)·h-1 and the selectivity to 1-octene is 49.65 wt%.
基金Supported by the National Natural Science Foundation of China（Nos.21373120, 21301098, 21071086, 21271110）, the National ＂111＂ Project of China＇s Higher Education（No.B 12015）, the Applied Basic Research Programs of Science and Technology Commission Foundation ofTianjin, China（Nos.13JCQNJC02000, 12JCYBJC13100）.
文摘TiO2 nanotubes supported amorphous Co-B（Co-B/TNTs） catalyst was prepared via impregnation- chemical reduction procedure. The catalyst was characterized with transmission electron microscopy（TEM）, ammonia temperature-programmed desorption（NH3-TPD）, thermogravimetry-differential thermal analysis（TG-DTA）, Fourier transform infrared spectroscopy（FTIR） and Raman spectroscopy. The effects of temperature and ratio of CO to HE on the hydroformylation of 1-octene were studied. At an optimized reaction temperature（150 ℃） and volume ratio of CO to H2（2：1）, the conversion of 1-octene can reach 97.4% with a selectivity of 23.1% for total aldehydes and n/i-aldehyde molar ratio of 40：60. To obtain higher selectivity for linear aldehydes, Co-B/TNTs modified with triphenylphosphine for the hydroformylation of 1-octene were investigated. When molar ratio of P/Co was 4, the yield of total aldehydes was the highest（31.6%） with a good selectivity for linear product（n/i-aldehyde molar ratio was 70：30）. In recycle use, the Co-B/TNTs catalyst modified with triphenylphosphine could be reused five times without reducing the activity and selectivity obviously. For a comparative study, all the Co-B/TNTs to catalyze the hydroformylation of other olefins exhibited high conversion under the optimized conditions.
