TRANSITION METAL CHEMISTRY
·
2019
·Vol. 44
·期 7
·681-688
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IF 1.016
Wang Jun,Liu Jinyi,Chen Liduo,Lan Tianyu,Wang Libo
A series of bispyridylamine ligands and chromium complexes designed for ethylene oligomerization have been synthesized, which was made up of both neutral organic ligand and inorganic anion. The compositions of these complexes have been fully characterized by spectroscopic and analytical methods. Catalysts ( Cr1 – Cr4) were evaluated in detail with methylaluminoxane (MAO) as an activator in the ethylene oligomerization. As a result, Cr1 achieved a higher catalytic activity of 2.93 × 10 5 g/(mol(Cr) h) and a higher selectivity of 55.34% toward the valuable C 8 compound using toluene as the solvent. The total selectivity to LAOs was 71.2%.
研究领域:
催化化学
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有机合成
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2021
·
IF 13.273
Yirong Feng,Mengbo Zhang,Haomiao Zhang,Jingdai Wang,Yongrong Yang
We present a 3D-printed continuous flow platform for controllable synthesis of isobutylaluminoxanes (IBAO), an effective olefin polymerization co-catalyst, via the highly exothermic hydrolytic reaction of triisobutylaluminum (TIBA). This platform encompasses modules of mixing and reaction, in-line separation, and in situ UV–vis characterization. In addition, two NMR protocols are established to validate the results of in-line UV–vis analysis (by 31 P NMR) and reveal product structures (by 1 H NMR). Measured temperature profiles over the reactor indicate essentially fast heat removal, ensuring inherent safety. Co-catalytic activities of IBAO are obtained from ethylene oligomerization experiments using an iron-based catalyst system at atmospheric pressure. Furthermore, we investigate the influence of key operating parameters including temperature, initial molar ratio between water and TIBA, initial TIBA concentration, and residence time. A high IBAO yield over 98% and a superior co-catalytic activity of ~ 5000 kg·(mol Fe) –1 ·h −1 are achieved with optimal parameters in this single-pass platform, demonstrating the advantages of process.
研究领域:
化学工程
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材料科学
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高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2021
·Vol. 36
·期 2
·e6509
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IF 4.105
Dan Li,Fengmin Ma,Lijun Guo,Jin Huang,Yu Zhang,Feng Li,Cuiqin Li
Late transition metal catalysts with single or multiple active centers have great attention in the ethylene oligomerization application owing to their unique properties. A new polynuclear (α-diimine) nickel(II) complex (PS-Ni complex) bearing the conjugated poly(Schiff-base) ligand (PS-ligand) was synthesized. The structures and the composition of the PS-ligand and the PS-Ni complex were characterized by Fourier transform infrared (FTIR) analysis, X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), thermogravimetric (TG) analysis, nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC). The PS-Ni complex was used as precatalyst in ethylene oligomerization combined with methylaluminoxane (MAO) and has good catalytic activity for ethylene oligomerization under mild conditions. Compared with the corresponding mononuclear (α-diimine) nickel(II) complex, the PS-Ni complex showed higher activity of 17.62 × 10 5 g/(mol Ni•h), and the main products were C 4 and C 6 olefins in cyclohexane when the dosage of precatalyst was 2 μmol, the Al/Ni molar ratio was 500, the ethylene pressure was 0.5 MPa, the reaction time was 60 min, and the reaction temperature was 25°C. The main oligomers were α-olefins, and the selectivity was up to 98.68%, due to the more electron-deficient catalytic centers of the conjugated structure of poly(Schiff-base) ligand.
研究领域:
化学
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催化材料科学
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高影响因子
JOURNAL OF COORDINATION CHEMISTRY
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2017
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IF 1.795
Jun Wang,Na Zhang,Weiguang Shi,Yiteng Shang,Cuiqin Li
Two hyperbranched bisphosphinoamine (PNP) ligands and chromium complexes were synthesized in good yield with 1.0 generation (1.0 G) hyperbranched macromolecules, chlorodiphenylphosphine (Ph2PCl) and CrCl3(THF)3 as raw materials. The hyperbranched PNP ligands and chromium complexes were characterized by FT-IR, 1H NMR, 31P NMR, UV and ESI-MS. Comparing with the chromium complexes, the hyperbranched PNP ligands, in combination with Cr(III), and activation by methylaluminoxane (MAO) in situ generated species with better catalytic performance for ethylene oligomerization. The effect of solvent, chromium source, ligand/Cr molar ratio, reaction temperature, Al/Cr molar ratio and reaction pressure on the catalytic activity and product selectivity were studied. The results showed that with increase of ligand/Cr molar ratio, reaction temperature and Al/Cr molar ratio, the catalytic activity increased at first and then decreased. However, the catalytic activity continuously increased with increase of reaction pressure. Under the optimized conditions, the catalytic system of hyperbranched PNP/Cr(III)/MAO led to catalytic activity of 2.68 × 105 g/(mol Cr·h) and 37.71% selectivity for C6 and C8.
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
JOURNAL OF APPLIED POLYMER SCIENCE
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2022
·Vol. 140
·期 3
·e53320
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IF 3.057
Lijun Guo,Yuxin Gao,Jin Huang,Jingqi Xue,Feng Li,Cuiqin Li
The functionalized covalent organic framework materials play an important role in catalytic application. A convenient tactic is developed to design and synthesize an imine-linked covalent organic frameworks (COFs) material (COF-PD) with abundant nitrogen atoms, which can provide coordination active site and facilitate the incorporation of COFs with nickel ions. Nickel-coordinated COF-PD complex (COF-PD-Ni) is prepared and used in ethylene oligomerization. COF-PD-Ni displays the highest catalytic activity of 1.98 × 10 5 g/(mol·Ni·h) in ethylene oligomerization with MAO as co-catalyst and cyclohexane as solvent. Various reaction parameters including reaction temperature, time, solvent, and the amount of cocatalyst are evaluated in detail, dramatically impacting the catalytic activities as well as the distribution of the products. What is more, the effect of COFs structure on the catalytic performance is also studied, suggesting more coordination sites were more important for high activity.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2022
·
IF 3.118
Dan Li,Feng Li,Hongyang Yu,Lijun Guo,Jin Huang,Jiahui Li,Cuiqin Li
Two-dimensional (2D)/three-dimensional (3D) conjugated porous polymers (CPPs) with a moderate surface area and tunable pore size are promising porous materials for catalysis. The imine-based 2D conjugated porous polymers (CPPs) was synthesized through the coupling of tris(4-aminophenyl)amine and p -phthalaldehyde and used as carrier to support nickel(II) to synthesize nickel-modified conjugated porous polymers (Ni@TAPA-CPPs) for ethylene oligomerization. The Ni@TAPA-CPPs catalyst with excellent thermal stability and pore size distributions revealed an efficient catalytic activity of 15.18 × 10 4 g/(mol Ni•h) and the selectivity of C 6 olefin for ethylene oligomerization in cyclohexane at room temperature. Moreover, the Ni@TAPA-CPPs catalyst was prepared simply and easy to recycle, and still had excellent catalytic activity after 3 consecutive cycles. This study exposes the two-dimensional (2D) conjugated porous polymers (CPPs) for the application of ethylene oligomerization and provides theoretical support for the application of CPPs in the field of ethylene oligomerization.
研究领域:
材料科学
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催化化学
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DOI
高影响因子
CATALYSIS LETTERS
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2021
·Vol. 152
·期 7
·2131-2140
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IF 3.186
Zhu Kehui,An Yunlei,Yu Fei,Liu Li,Zhong Liangshu
The structure-performance evolution of Co/N-AC catalyst during ethylene oligomerization was investigated in detail. It was found that the catalytic activity sharply decreased in the first 30 h with the ethylene conversion decreasing from 64 to 4%. Butene selectivity increased gradually in the first 10 h then remained about 74%, while the selectivity for hexene and octene exhibited an opposite trend. The ratio of α-olefin to isomers for butene increased greatly with time on stream and most of the generated butene was 1-butene. Based on the structure characterization at different reaction stages, CoO x was suggested to be major active phase and the coverage of long-chain hydrocarbons as well as the loss of surface CoO x active sites due to size growth of Co 3 O 4 nanoparticles were the main reasons for catalytic deactivation. Graphic Abstract The structure-performance evolution of Co/N-AC catalyst during ethylene oligomerization was investigated and the coverage of long-chain hydrocarbons as well as the loss of surface CoO x active sites due to size growth of Co 3 O 4 nanoparticles were the main reasons for catalytic deactivation
研究领域:
化学工程
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催化材料科学
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DOI
高影响因子
POLYMER BULLETIN
·
2021
·Vol. 79
·期 6
·4219-4231
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IF 2.87
Zhang Na,Wu Yansong,Li Yuying,Chen Liduo,Zhang Mingshui,Wang Jun
A novel star iminopyridyl ligand was synthesized in modest yield with 1.0 G star macromolecule and pyridine-2-carboxaldehyde as the raw materials. Reactions of the star iminopyridyl ligand with Fe(II), Co(II) and Ni(II) salts afforded metal complexes (Cat-Fe, Cat-Co and Cat-Ni) in good yields. The compounds were characterized by FT-IR, 1 H NMR, 13 C NMR, UV–Vis, ESI–MS and ICP-MS. In the presence of methylalumoxane (MAO), the iron, cobalt and nickel complexes have demonstrated higher ethylene oligomerization activity (up to 4.28 × 10 5 g/(mol Co h)), affording C 4 as the major product as well as C 6 , C 8 and C 10-18 oligomers. The catalytic activity was quite sensitive to the kind of species. The nature of solvent and co-catalyst significantly affected both the catalytic activity and product distribution. Moreover, the effect of oligomerization parameters (reaction temperature, [Al]/[Co] molar ratio, ethylene pressure) on the catalytic activity and the product distribution was investigated.
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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DOI
高影响因子
MICROPOROUS AND MESOPOROUS MATERIALS
·
2013
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IF 3.365
Sen Lin,Lei Shi,Hongpeng Zhang,Na Zhang,Xianfeng Yi,Anmin Zheng,Xuebing Li
Al-SBA-15 containing plug structures inside straight channels have been hydrothermally synthesized through a one-step synthesis strategy in an environmentally friendly acid-free medium. The effects of steaming, alkali, and acid post-treatments on the structural properties were investigated by powder X-ray diffraction (XRD), nitrogen adsorption–desorption at 77 K, transmission electron microscopy (TEM), scanning electron microscopy (SEM), FT-IR spectrum, 27 Al MAS NMR, and inductively coupled plasma (ICP) analyses. The presence of the plugs can significantly enhance structural stability against steaming or alkali post-treatments. Acid post-treatment can be a very simple and convenient technique for adjusting the textural properties of plug-containing Al-SBA-15, and especially for optimizing the accessibility to active sites. Acid post-treatment at the low temperatures of 313 and 323 K results in the formation of a larger specific surface area (905 m 2 /g) and pore volume (0.94 cm 3 /g) through an “open door” effect in the plugs, without eliminating any of the plugs from the channels. In particular, nearly half of the secondary micropores on the pore walls were preserved. In contrast, raising the acid post-treatment temperature further to 333 and 343 K caused a “closed doors” effect through the blockage of pores in the plugs by the extracted fragments. After loading with nickel, the catalyst exhibited a higher yield of C 10+ olefins in ethylene oligomerization , and more importantly, after steaming and acid post-treatments at higher temperatures, the samples showed shape selectivity for the C 16 olefin.
研究领域:
材料科学
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催化化学
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产品关联
DOI
高影响因子
INORGANICA CHIMICA ACTA
·
2017
·
IF 2.002
Na Zhang,Jiaming Wang,Hongliang Huo,Liduo Chen,Weiguang Shi,Cuiqin Li,Jun Wang
A series of hyperbranched iminopyridyl ligands [ethylenediamine as terminal groups (L1), 1,4-butanediamine as terminal groups (L2), 1,6-hexamethylenediamine as terminal groups (L3)] were prepared. Ligands L1-L3 were reacted with MCl 2 ·nH 2 O (M = Fe, Co, Ni) to form three types of complexes (C1-C5). Both L1-L3 and C1-C5 were fully characterized by FT-IR, 1 H NMR, UV and ESI-MS. The nickel complexes exhibited better catalytic properties than iron and cobalt complexes for ethylene oligomerization. On activation with methylaluminoxane (MAO), the nickel complex C1 exhibited moderate catalytic activities up to 1.56 × 10 6 g mol −1 h −1 for ethylene oligomerization and the oligomers showed Schulz-Flory distribution. However, on activation with EtAlCl 2 , the nickel complex C1 exhibited higher catalytic activity up to 8.94 × 10 6 g mol −1 h −1 for ethylene oligomerization, but the products were mainly alkylated-toluenes. The influence of the solvent and reaction parameters such as reaction temperature, ethylene pressure and Al/Ni molar ratio on the catalytic behavior of the nickel complex C1 was also investigated. Moreover, in comparison with the catalytic activity and the distribution of oligomers obtained with related hyperbranched salicylaldimine nickel complex and other non-hyperbranched iminopyridyl nickel complexes, the catalytic activity and the content of low carbon number olefins (C 4 and C 6 ) obtained in this work possessed relatively higher.
研究领域:
化学
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材料科学
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高影响因子
ChemistrySelect
·
2023
·Vol. 8
·期 13
·e202204866
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IF 2.1
Jingqi Xue,Lijun Guo,Hongliang Huo,Lili Ma,Jin Huang,Feng Li,Cuiqin Li
Graphical Dendritic macrocyclic Schiff base ligands with 1.0G dendrimer PAMAM and terephthalaldehyde were synthesized in different solvents. And the corresponding nickel complexes were also synthesized to be used for ethylene oligomerization. Two synthesized complexes displayed higher catalytic activity and higher selectivity for low-carbon olefin compared with dendritic salicylaldehyde-imine nickel (II) catalyst because of the steric hindrance of dendritic ring. The functionalized dendrimers play an important role in catalytic application. A dendritic Schiff base macrocyclic compound was designed and synthesized with the 1.0 generation dendrimer polyamidoamine (1.0G PAMAM) and terephthalaldehyde for ethylene oligomerization. The role of solvent in the synthesized process of dendritic macrocyclic Schiff base ligand was studied. Surprisingly, intermolecular or intramolecular cyclization occurred and formed bicyclic Schiff base ligand ( Ligand 1 ) and polycyclic Schiff base ligand ( Ligand 2 ). And their corresponding nickel complexes ( Catalyst 1 and Catalyst 2 ) were also synthesized with NiCl 2 (DME) as material to be used for ethylene oligomerization. The effects of the reaction parameters and the chemical structure of the ligand on the catalytic behavior were investigated with methyl-aluminoxane (MAO) as cocatalyst, and Catalyst 1 and Catalyst 2 displayed the high catalytic activity and the high selectivity for low-carbon olefin in ethylene oligomerization. Catalyst 2 based on Ligand 2 had a higher catalytic activity of 9.12×10 4 g (mol Ni h) −1 in ethylene oligomerization because of large dendritic ring in the ligand for ethylene diffusion and mass transfer. Moreover, two synthesized nickel complexes based on dendritic macrocyclic Schiff base ligand had a higher catalytic activity compared with the corresponding dendritic salicylaldehydeimine nickel (II) catalyst.
研究领域:
化学
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催化材料科学
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高影响因子
APPLIED ORGANOMETALLIC CHEMISTRY
·
2023
·Vol. 37
·期 12
·e7276
·
IF 3.9
Liduo Chen,Jinyan Tan,Tianyu Lan,Hongliang Huo,Liyuan Sun,Yan Jiang,Na Zhang,Cuiqin Li,Jun Wang
Salicylaldehyde imine nickel complexes Ni1-Ni10 containing different electron-donating and electron-withdrawing groups on benzene rings were synthesized, using ethylenediamine, salicylaldehyde derivatives with different substituents and nickel chloride hexahydrate as raw materials. Structure characterization, such as elemental analysis, Fourier transform infrared (FT-IR), nuclear magnetic resonance (NMR), ultraviolet–visible (UV–Vis), and electrospray ionization mass spectrometry (ESI-MS), confirmed that the structure of synthesized complexes was consistent with the theoretical. Salicylaldehyde imine nickel complexes exhibited good catalytic activity in ethylene oligomerization process, and complexes containing electron-donating groups on the benzene ring had higher catalytic activity than complexes containing electron-withdrawing groups on the benzene ring. With the increase of steric hindrance of phenol hydroxyl ortho-substituents, the catalytic activity decreased, as well as the catalytic selectivity toward olefins with higher carbon number. The relationship between structure and catalytic properties was further studied by density functional theory (DFT) calculations, and the possible mechanism of nickel complexes catalyzing ethylene oligomerization was proposed.
研究领域:
化学
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催化反应
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理论计算
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高影响因子
危险品化学品经营许可证（带存储）