Nickel catalysts based on phenyl ether-pyrazol ligands: Synthesis, XPS study, and use in ethylene oligomerization
摘要:
A series of nickel(II) complexes bearing phenyl ether-pyrazol ligands [NiCl2L] (Ni1: L=3,5-dimethyl-1-(3-phenoxypropyl)-1H-pyrazole; Ni2: L=1-(3-phenoxypropyl)-3-phenyl-1H-pyrazole; Ni3: L=3,5-di-tert-butyl-1-(3-phenoxypropyl)-1H-pyrazole; Ni4: L=1-(3-phenoxypropyl)-1H-pyrazole) were synthesized and fully characterized by elemental analysis, high-resolution mass spectrometry (HRMS) and X-ray photoelectron spectroscopy (XPS). X-ray photoelectron data illustrates that the probability of (co)existing dimeric species increases in the following order: Ni4 < Ni1 < Ni2 < Ni3. All nickel precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [TOF = 18.4-45.7 x 10(3) mol(ethylene)(mol(Ni))(-1) h(-1))] with good selectivities for 1-butene produced (62.6-80.7%). The ligand environment regarding the substituents on the pyrazolyl unit as well as the reaction parameters influence the catalytic performance and selectivity toward production of 1-butene. When activated with ethylaluminum sesquichloride (Et3Al2Cl3, EASC), Nil displayed low catalytic activity (TOF = 9300 (mol C2H4).(mol Ni-1 h(-1)); however, the 1-butene selectivity was increased, attaining 92.5%. The use of triphenylphosphine (PPh3) as auxiliary ligand afforded highly active catalyst system [TOF = 118.3 x 10(3) mol(ethylene)(mol(Ni))(-1) h(-1))] with poor selectivity for production of 1-butene (13.7%). (C) 2013 Elsevier B.V. All rights reserved.
Nickel catalysts based on phenyl ether-pyrazol ligands: Synthesis, XPS study, and use in ethylene oligomerization
摘要:
A series of nickel(II) complexes bearing phenyl ether-pyrazol ligands [NiCl2L] (Ni1: L=3,5-dimethyl-1-(3-phenoxypropyl)-1H-pyrazole; Ni2: L=1-(3-phenoxypropyl)-3-phenyl-1H-pyrazole; Ni3: L=3,5-di-tert-butyl-1-(3-phenoxypropyl)-1H-pyrazole; Ni4: L=1-(3-phenoxypropyl)-1H-pyrazole) were synthesized and fully characterized by elemental analysis, high-resolution mass spectrometry (HRMS) and X-ray photoelectron spectroscopy (XPS). X-ray photoelectron data illustrates that the probability of (co)existing dimeric species increases in the following order: Ni4 < Ni1 < Ni2 < Ni3. All nickel precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [TOF = 18.4-45.7 x 10(3) mol(ethylene)(mol(Ni))(-1) h(-1))] with good selectivities for 1-butene produced (62.6-80.7%). The ligand environment regarding the substituents on the pyrazolyl unit as well as the reaction parameters influence the catalytic performance and selectivity toward production of 1-butene. When activated with ethylaluminum sesquichloride (Et3Al2Cl3, EASC), Nil displayed low catalytic activity (TOF = 9300 (mol C2H4).(mol Ni-1 h(-1)); however, the 1-butene selectivity was increased, attaining 92.5%. The use of triphenylphosphine (PPh3) as auxiliary ligand afforded highly active catalyst system [TOF = 118.3 x 10(3) mol(ethylene)(mol(Ni))(-1) h(-1))] with poor selectivity for production of 1-butene (13.7%). (C) 2013 Elsevier B.V. All rights reserved.
Chromium Complexes Supported by Phenyl Ether‐Pyrazolyl [N,O] Ligands as Catalysts for the Oligo‐ and Polymerization of Ethylene
作者:Jorge L.S. Milani、Osvaldo L. Casagrande
DOI:10.1002/aoc.5984
日期:2020.12
Cr2 and Cr3 showed moderate activity in ethylene oligomerization [TOF = 17,900–29,200 mol (ethylene)·mol (Cr)−1·h−1 at 80 °C] with Schultz‐Flory distribution of oligomers (K = 0.54–0.66) and production of polymer varying from 2.8 to 6.7 wt.%. On the other hand, under identical oligomerization conditions, Cr1/MAO behaved as a polymerizationcatalyst generating predominantly polyethylene (63.7 wt%).
Nickel catalysts based on phenyl ether-pyrazol ligands: Synthesis, XPS study, and use in ethylene oligomerization
作者:Ana H.D.P.S. Ulbrich、Roberta R. Campedelli、Jorge L. Sônego Milani、João H.Z. dos Santos、Osvaldo de L. Casagrande
DOI:10.1016/j.apcata.2012.12.031
日期:2013.2
A series of nickel(II) complexes bearing phenyl ether-pyrazol ligands [NiCl2L] (Ni1: L=3,5-dimethyl-1-(3-phenoxypropyl)-1H-pyrazole; Ni2: L=1-(3-phenoxypropyl)-3-phenyl-1H-pyrazole; Ni3: L=3,5-di-tert-butyl-1-(3-phenoxypropyl)-1H-pyrazole; Ni4: L=1-(3-phenoxypropyl)-1H-pyrazole) were synthesized and fully characterized by elemental analysis, high-resolution mass spectrometry (HRMS) and X-ray photoelectron spectroscopy (XPS). X-ray photoelectron data illustrates that the probability of (co)existing dimeric species increases in the following order: Ni4 < Ni1 < Ni2 < Ni3. All nickel precatalysts, activated with methylaluminoxane (MAO), exhibited moderate to high activities for ethylene oligomerization [TOF = 18.4-45.7 x 10(3) mol(ethylene)(mol(Ni))(-1) h(-1))] with good selectivities for 1-butene produced (62.6-80.7%). The ligand environment regarding the substituents on the pyrazolyl unit as well as the reaction parameters influence the catalytic performance and selectivity toward production of 1-butene. When activated with ethylaluminum sesquichloride (Et3Al2Cl3, EASC), Nil displayed low catalytic activity (TOF = 9300 (mol C2H4).(mol Ni-1 h(-1)); however, the 1-butene selectivity was increased, attaining 92.5%. The use of triphenylphosphine (PPh3) as auxiliary ligand afforded highly active catalyst system [TOF = 118.3 x 10(3) mol(ethylene)(mol(Ni))(-1) h(-1))] with poor selectivity for production of 1-butene (13.7%). (C) 2013 Elsevier B.V. All rights reserved.