کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
40406 45852 2013 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Nickel catalysts based on phenyl ether-pyrazol ligands: Synthesis, XPS study, and use in ethylene oligomerization
موضوعات مرتبط
مهندسی و علوم پایه مهندسی شیمی کاتالیزور
پیش نمایش صفحه اول مقاله
Nickel catalysts based on phenyl ether-pyrazol ligands: Synthesis, XPS study, and use in ethylene oligomerization
چکیده انگلیسی

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 × 103 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), Ni1 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 × 103 mol(ethylene)(mol(Ni))−1 h−1)] with poor selectivity for production of 1-butene (13.7%).

Figure optionsDownload high-quality image (88 K)Download as PowerPoint slideHighlights
► Nickel complexes supported by pheny ether-pyrazol ligands.
► The probability of (co)existing dimeric species increases in the following order: Ni4 < Ni1 < Ni2 < Ni3.
► Nickel precatalysts exhibit high activities in ethylene oligomerization.
► Selectivities for 1-butene produced varying from 57 to 92.5%.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Applied Catalysis A: General - Volume 453, 26 February 2013, Pages 280–286
نویسندگان
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