Synthesis, Characterization and Ethylene Oligomerization Studies of Chromium Complexes Bearing Imino-Furfural Ligands
摘要:
Uma serie de complexos de cromo(III) contendo ligantes imina-furfural (Cr1-Cr4) foram sintetizados e caracterizados por espectrometria de massas de alta resolucao (HRMS). Todos os pre-catalisadores de cromo, ativados com metilaluminoxano (MAO), apresentaram atividade moderada na oligomerizacao do etileno [frequencia de rotacao (TOF) = 11.800-23.200 mol(etileno) mol(Cr)(-1) h(-1))] produzindo oligomeros na faixa de C-4-C12+ e com boa seletividade para olefinas-alpha. Os pre-catalisadores de cromo(III) formados in situ pela combinacao do ligante imina-furfural L-1 com [CrCl3(THF)(3)] ou [Cr(acac)(3)] apresentaram baixas atividades, produzindo oligomeros juntamente com quantidades variaveis de polietileno. A utilizacao de diferentes compostos de cromo e cocatalisadores influenciam a atividade bem como a seletividade para a producao de olefinas-a, o que sugere que diferentes especies cataliticas sao formadas.A series of chromium(III) complexes bearing imino-furfural ligands (Cr-1-Cr-4) were synthesized and characterized by high-resolution mass spectrometry (HRMS). All chromium precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [turnover frequency (TOF) = 11,008-23,200 mol(ethylene) mol(Cr)(-1) h(-1))] producing oligomers in the range C-4-C12+ with good selectivity for a-olefins. The in situ chromium precatalysts formed by mixing imino-furfural ligand L1 with [CrCl3(THF)(3)] or [Cr(acac)(3)] showed low activities, producing oligomers together with varying amounts of polyethylene. The use of different chromium sources and cocatalysts influences the activity as well as the selectivities toward a-olefin production, which suggests that different active species are formed.
Synthesis, Characterization and Ethylene Oligomerization Studies of Chromium Complexes Bearing Imino-Furfural Ligands
摘要:
Uma serie de complexos de cromo(III) contendo ligantes imina-furfural (Cr1-Cr4) foram sintetizados e caracterizados por espectrometria de massas de alta resolucao (HRMS). Todos os pre-catalisadores de cromo, ativados com metilaluminoxano (MAO), apresentaram atividade moderada na oligomerizacao do etileno [frequencia de rotacao (TOF) = 11.800-23.200 mol(etileno) mol(Cr)(-1) h(-1))] produzindo oligomeros na faixa de C-4-C12+ e com boa seletividade para olefinas-alpha. Os pre-catalisadores de cromo(III) formados in situ pela combinacao do ligante imina-furfural L-1 com [CrCl3(THF)(3)] ou [Cr(acac)(3)] apresentaram baixas atividades, produzindo oligomeros juntamente com quantidades variaveis de polietileno. A utilizacao de diferentes compostos de cromo e cocatalisadores influenciam a atividade bem como a seletividade para a producao de olefinas-a, o que sugere que diferentes especies cataliticas sao formadas.A series of chromium(III) complexes bearing imino-furfural ligands (Cr-1-Cr-4) were synthesized and characterized by high-resolution mass spectrometry (HRMS). All chromium precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [turnover frequency (TOF) = 11,008-23,200 mol(ethylene) mol(Cr)(-1) h(-1))] producing oligomers in the range C-4-C12+ with good selectivity for a-olefins. The in situ chromium precatalysts formed by mixing imino-furfural ligand L1 with [CrCl3(THF)(3)] or [Cr(acac)(3)] showed low activities, producing oligomers together with varying amounts of polyethylene. The use of different chromium sources and cocatalysts influences the activity as well as the selectivities toward a-olefin production, which suggests that different active species are formed.
Synthesis and characterization of ether-imine-furfural [ONO] nickel(II) complexes and their application in oligomerization of ethylene
作者:J.L.S. Milani、A.C.A. Casagrande、P.R. Livotto、Osvaldo L. Casagrande
DOI:10.1016/j.apcata.2016.06.019
日期:2016.8
improvement in the TOF [69.3 × 103 mol(ethylene) mol(Ni)−1 h−1] with lower selectivity for 1-butene. Higher activity was obtained using EASC as cocatalyst [206.1 × 103 mol(ethylene) mol(Ni)−1 h−1] along with a drastic reduction in the selectivity for 1-butene (10.4 wt.%). Under optimized conditions [[Ni] = 5 μmol, 30 °C, oligomerization time = 20 min, 20 bar ethylene, MAO as cocatalyst (500 equiv)], precatalyst
一系列新的通式为NiCl 2(L)} 2 [ Ni1,L = 5-甲基-2-(C 4 H 3 O-2-CH N)C 2 H 4 OPh的Ni(II)配合物;Ni 2,L = 5-甲基-2-(C 4 H 3 O-2-CH N)Ph-2-OPh;Ni 3,L = 2-(C 4 H 3 O-2-CH N)Ph-2-OPh;Ni 4,L = 5-甲基-2-(C 4 H 3 O-2-CH N)CH 2制备了Ph-2-OMe,并通过红外光谱,元素分析,高分辨率质谱(HRMS)和X射线光电子能谱(XPS)对其进行了表征。XPS数据表明,醚/糠醛侧链供体基团与镍金属中心没有相互作用。密度泛函理论研究表明,形成了以醚亚胺糠醛为单齿配体的镍二聚体物种。所有具有改进的聚甲基铝氧烷性能(PMAO-IP)活化的镍预催化剂,对乙烯的低聚反应[TOF = 14.7–57.3×10 3 mol(乙烯)mol(Ni)-1
Synthesis, Characterization and Ethylene Oligomerization Studies of Chromium Complexes Bearing Imino-Furfural Ligands
作者:Ana H. D. P. S. Ulbrich、Jorge L. S. Milani、Paolo R. Livotto、Jean-François Carpentier、Osvaldo L. Casagrande Jr.
DOI:10.5935/0103-5053.20140274
日期:——
Uma serie de complexos de cromo(III) contendo ligantes imina-furfural (Cr1-Cr4) foram sintetizados e caracterizados por espectrometria de massas de alta resolucao (HRMS). Todos os pre-catalisadores de cromo, ativados com metilaluminoxano (MAO), apresentaram atividade moderada na oligomerizacao do etileno [frequencia de rotacao (TOF) = 11.800-23.200 mol(etileno) mol(Cr)(-1) h(-1))] produzindo oligomeros na faixa de C-4-C12+ e com boa seletividade para olefinas-alpha. Os pre-catalisadores de cromo(III) formados in situ pela combinacao do ligante imina-furfural L-1 com [CrCl3(THF)(3)] ou [Cr(acac)(3)] apresentaram baixas atividades, produzindo oligomeros juntamente com quantidades variaveis de polietileno. A utilizacao de diferentes compostos de cromo e cocatalisadores influenciam a atividade bem como a seletividade para a producao de olefinas-a, o que sugere que diferentes especies cataliticas sao formadas.A series of chromium(III) complexes bearing imino-furfural ligands (Cr-1-Cr-4) were synthesized and characterized by high-resolution mass spectrometry (HRMS). All chromium precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [turnover frequency (TOF) = 11,008-23,200 mol(ethylene) mol(Cr)(-1) h(-1))] producing oligomers in the range C-4-C12+ with good selectivity for a-olefins. The in situ chromium precatalysts formed by mixing imino-furfural ligand L1 with [CrCl3(THF)(3)] or [Cr(acac)(3)] showed low activities, producing oligomers together with varying amounts of polyethylene. The use of different chromium sources and cocatalysts influences the activity as well as the selectivities toward a-olefin production, which suggests that different active species are formed.