Russian Journal of Physical Chemistry A
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2020
·Vol. 94
·期 5
·1024-1033
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IF 0.719
Na Zhang,Chen Liduo,Li Cuiqin,Wang Jun
Abstract Two kinds of soft-bridged iminopyridyl ligands and their metal (iron and cobalt) complexes were synthesized. All soft-bridged iminopyridyl ligands and metal complexes were fully characterized by FT-IR, 1 H NMR, UV–Vis, ESI-MS, and ICP-MS. Upon activation with methylaluminoxane (MAO), these metal complexes exhibited moderate catalytic activity up to the range of 10 5 g/(mol Me h) for ethylene oligomerization, and butene was the major product, while for the cobalt complexes, activation with EtAlCl 2 in toluene produced Friedel–Crafts toluene alkylation products. In the catalytic systems, cobalt complexes exhibited better catalytic activity and selectivity towards higher carbon number olefins (≥C 8 ) than their iron analogues. The correlations between metal complexes and their catalytic activities and product distribution were investigated in detail under various reaction parameters such as reaction temperature, ethylene pressure and amount of co-catalyst. Under optimized conditions ([Co] = 7 μmol, 35°C, 1.0 MPa, MAO-to-Co = 500), soft-bridged iminopyridyl cobalt catalyst Co1 led to catalytic activity of 6.18 × 10 5 g/(mol Co h) and 29.97% selectivity for higher carbon number olefins. However, under optimized conditions ([Fe] = 7 μmol, 25°C, 1.0 MPa, MAO-to-Fe = 500), soft-bridged iminopyridyl iron catalyst Fe1 led to catalytic activity of 4.73 × 10 5 g/(mol Fe h) and 22.60% selectivity for higher carbon number olefins.
研究领域:
化学
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材料科学
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催化反应
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高影响因子
CHEMICAL PAPERS
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2016
·Vol. 71
·期 6
·1037-1046
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IF 1.326
Zhang Na,Wang Si-han,Song Lei,Li Cui-qin,Wang Jun
A series of novel 1.0 generation (1.0G) hyperbranched macromolecules bridged salicylaldimine cobalt complexes were synthesized in high yields. The compounds were characterized by fourier transform infrared (FT-IR) spectroscopy, ultraviolet (UV) visible spectroscopy, electrospray ionization mass spectrometry (ESI–MS), elemental analysis and thermal gravimetric analysis (TGA), as well as were investigated as precatalysts for the oligomerization of ethylene. Upon activation with methylaluminoxane (MAO) and diethylaluminumchloride (DEAC), the cobalt precatalysts showed moderate catalytic activities in the range of 10 5 g/(mol Co h) in ethylene reactivity with the high selectivity for the butenes and high carbon number olefins products. The correlation between cobalt complexes and their catalytic activities and product distribution were investigated in detail under various reaction parameters. The research results showed that the catalytic activities of precatalysts increased with the increase of ethylene pressure and Al/Co molar ratio; however, the catalytic activities firstly increased and then decreased with the increase of reaction temperature. The highest activity of 2.54 × 10 5 g/(mol Co h) and 50.18% selectivity of high number carbon olefins was obtained under the reaction temperature of 25 °C, ethylene pressure of 0.5 MPa, and Al/Co molar ratio of 1500. In addition, the nature of solvent and co-catalyst, as well as the structure of precatalysts, significantly affected both the activity and the product distribution of the resultant catalysts.
研究领域:
有机化学
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催化化学
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DOI
高影响因子
ADVANCES IN POLYMER TECHNOLOGY
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2016
·Vol. 37
·期 2
·629-636
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IF 1.114
Jun Wang,Na Zhang,Cuiqin Li,Weiguang Shi,Zhiyu Lin
A series of new hyperbranched salicylaldimine nickel complexes were synthesized by the Schiff's base and the complexation reactions with 1.0 generation hyperbranched macromolecules, salicyladehyde and nickel chloride hexahydrate as materials by employing two-step synthesis and one-pot synthesis, respectively. The hyperbranched salicylaldimine ligands and the complexes were characterized by FT-IR, 1 H NMR, UV, and ESI-MS. All nickel complexes, activated with Methylaluminoxane, exhibited high activities for ethylene oligomerization (TOF = 1.92–4.93 g/mol Ni h) and showed good selectivities for the longer chain oligomers produced (36.35–60.33%). When activated with ethylaluminum dichloride, it was found that a tandem process occurred in which ethylene oligomerization was followed by Friedel–Crafts alkylation of the reaction solvent, toluene. On increasing the pressure of ethylene and Al/Ni ratio, the catalytic activities of precatalyst increased and the processes became more selective for the shorter oligomers. Not only the polymerized parameters but also the length of alkyl chain of the ligands influenced the catalytic activities and selectivities for the longer chain oligomers. The catalytic activities and selectivities for the longer chain oligomers declined with the increase in length of alkyl chain of ligand.
研究领域:
有机化学
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催化化学
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DOI
高影响因子
POLYMER ENGINEERING AND SCIENCE
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2019
·Vol. 59
·期 5
·1010-1016
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IF 1.92
Jian Ye,Yu Li,Binbo Jiang,Wei Zhang,Jingdai Wang,Zuwei Liao,Zhengliang Huang,Yongrong Yang,Zhibin Ye
For the purpose of reducing the simultaneous production of insoluble polymers during the bis(imino)pyridyl iron-catalyzed ethylene oligomerization, various modifiers like phenol, anisole, 1-naphthol, 2-naphthol, benzoic acid, cyclohexanol, cyclohexyl carbinol, and benzyl alcohol were employed to modify the co-catalyst methylaluminoxane (MAO) and tune the catalytic behaviors in this work. It was found that phenol could serve as a good polymer-retarding modifier, the phenolic hydroxyl group was responsible for the interactions with MAO. Further increasing the aromatic ring size from phenol to naphthols was beneficial for retarding the polymer formation. Meanwhile, an increase of the acidity of the modifiers would promote the interactions between them and MAO, but also tend to easily deactivate the catalytic system. In addition, the alcohol modifiers with a phenol-like structure were also studied, their deactivation effect was found to be stronger than their polymer-retarding effect, making them difficult to obtain a satisfactory low polymer formation with the catalytic system remaining a high activity. POLYM. ENG. SCI., 59:1010–1016, 2019. © 2019 Society of Plastics Engineers
研究领域:
高分子化学
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催化化学
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DOI
高影响因子
Journal of Macromolecular Science Part A-Pure and Applied Chemistry
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2016
·
IF 0.963
Jun Wang,Huan-Yu Li,Lei Song,Wei-Guang Shi,Na Zhang,Cui-Qin Li
Two novel dendritic poly(amido-amine) (PAMAM) bridged salicylaldimine ligands were synthesized by Schiff base reaction using 1.0 generation dendritic PAMAM as bridged groups. The cobalt complex with 1,4-butanediamine as core (C1) and the cobalt complex with 1,6-hexanediamine as core (C2) based on dendritic PAMAM bridged salicylaldimine ligands were prepared by metallic coordination reaction, respectively. The structures of the ligands and the dendritic cobalt complexes were characterized by fourier transform infrared (FTIR), ultraviolet spectra (UV), hydrogen nuclear magnetic resonance (1H NMR) and electrospray ionization mass spectra (ESI-MS). The complexes C1 and C2 were evaluated as catalyst precursors for ethylene oligomerization after being activated with methylaluminoxane (MAO), diethylaluminum chloride (Et2AlCl), ethylaluminium dichloride (EtAlCl2) and ethylaluminum sesquichloride (EASC). The dendritic cobalt complexes exhibited the highest activity and selectivity for high carbon oligomers with EASC as activator. Under the conditions of 1.0 MPa, 25°C and Al/Co molar ratio 1500, the catalytic activity and selectivity for C10–C20 using C1 were 3.44×106 g·(mol Co·h)−1 and 76.53% after activation with EASC, and the catalytic activity and selectivity for C10–C20 using C2 were 3.42×106 g·(mol Co·h)−1 and 84.50%, respectively.
研究领域:
无机化学
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有机金属化学
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高分子化学
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催化化学
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材料科学
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高影响因子
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