新型超支化镍系催化剂的合成及对乙烯齐聚的催化性能

以直链十二胺为核的0.5代超支化大分子（R₁₂-0.5G）和丁二胺为原料,合成出一种新型的1.0代超支化大分子（R₁₂-1.0G）。然后以R₁₂-1.0G、水杨醛和NiCl₂·6H₂O为原料,依次经过希夫碱反应和络合反应合成了一种新型的超支化水杨醛亚胺镍系催化剂。FTIR、¹H NMR、UV和MS证实合成产物的结构与理论结构相符。在合成的基础上,并对该催化剂催化乙烯齐聚的性能进行了研究。考察了溶剂种类、反应温度、反应压力、Al/Ni比等条件对该催化剂催化乙烯齐聚性能的影响。结果表明,该催化剂具有良好催化乙烯齐聚的性能,当以甲苯为溶剂,在甲基铝氧烷（MAO）活化下,随着反应压力和Al/Ni比增加,催化活性增加;而催化活性随着反应温度的增加先升高后下降;在反应温度为25℃、反应压力为0.5MPa、Al/Ni比为1500时,该催化剂的活性可达5.03×10⁵g/（molNi·h）,聚合产物主要是C₆以下的低碳烯烃,含量高达89%以上。相同条件下,其催化乙烯齐聚的活性低于与其具有类似结构的“扫帚型”镍系催化剂。     

水杨醛亚胺镍配合物在甲苯中催化乙烯聚合

研究了水杨醛亚胺中性镍配合物在甲苯中催化乙烯聚合。在膦捕捉剂乙酰丙酮乙烯基铑[Rh(acac) (C_2H_4)_2]存在下,聚合活性和聚乙烯(PE)的相对分子质量均随乙烯压力的升高呈递增趋势,但随聚合温度升高而降低。由双(1,5-环辛二烯)合镍[Ni(COD)_2]作助催化剂,乙烯聚合的活性较高,但所得PE的相对分子质量、熔点和结晶度较低。动态流变研究表明,助催化剂可增加PE的支化度和降低其相对分子质量,以提高其高温加工性能。核磁共振氢谱、碳谱和广角X射线衍射研究表明,不同助催化剂所得PE的结构类似,而支化度分别为每1000个C中8和16个支链。     

水杨醛亚胺合镍金属催化剂的合成、表征及应用

采用多步偶联的方式合成了基于氧杂蒽骨架的配体及相应的镍金属配合物,通过核磁共振谱、碳谱及元素分析对配合物及其配体进行结构表征分析,利用单晶衍射阐述了配合物的立体结构.采用该配合物与含铝助剂配合使用能有效催化乙烯寡聚,活性最高可达到5×106g/(mol·h),产品组成以C4为主.     

水杨醛亚胺钛配合物的合成、表征及其催化乙烯聚合

以水杨醛和一系列取代苯胺为原料,通过席夫碱缩合反应合成了水杨醛亚胺类配体(L1～L4),将其与钛盐前体TiCl_4·2THF进一步反应,获得水杨醛亚胺钛配合物1～4。用元素、红外分析和热重等方法表征了配体和配合物的结构。将水杨醛亚胺钛配合物作为催化剂,应用于乙烯聚合催化反应,研究了亚胺基苯环上取代基的空间位阻对乙烯聚合催化剂的催化活性、分子量、分子量分布的影响。     

水杨醛亚胺类[O~-NS]三齿钛配合物的合成及催化乙烯聚合

合成了两种新型的带边臂硫原子的水杨醛亚胺型[O-NS]三齿配体配位的钛配合物Ti1和Ti2。研究了两种配合物在助催化剂MMAO作用下催化乙烯聚合的性能。结果表明,配合物Ti1表现出了中等的催化活性,最高可达73.8 kg/(mol·h·atm);将亚胺键还原后的配合物Ti2在25℃、Al/Ti比为2 000时,催化活性达188.5 kg/(mol·h·atm),最高活性提高了2倍多。     

水杨醛亚胺类[O~-NS]三齿钛配合物的合成及催化乙烯聚合

合成了两种新型的带边臂硫原子的水杨醛亚胺型[O-NS]三齿配体配位的钛配合物Ti1和Ti2。研究了两种配合物在助催化剂MMAO作用下催化乙烯聚合的性能。结果表明,配合物Ti1表现出了中等的催化活性,最高可达73.8 kg/(mol·h·atm);将亚胺键还原后的配合物Ti2在25℃、Al/Ti比为2 000时,催化活性达188.5 kg/(mol·h·atm),最高活性提高了2倍多。     

α-二亚胺镍催化剂催化乙烯溶液聚合的性能北大核心

合成了4种不同结构的配体及6种α-二亚胺镍金属配合物,并表征了配体及配合物的结构。结果表明:所合成的配合物显示出较高的活性和优异的热稳定性;以甲基铝氧烷为助催化剂,甲苯为溶剂,聚合温度为100℃时,配合物Ni3的活性可达3.45×10~6 g/(mol·h);配体结构对催化剂活性和所得聚合物的结构具有较大的影响;用配合物Ni1制备的聚合物的重均分子量为1.8×10~4;采用具有较大位阻的配合物Ni3可得到更高相对分子质量的聚合物。     

新型Ni(Ⅱ)系催化体系催化乙烯齐聚的研究

合成了三种PNP配体,与Ni(Ⅱ)形成催化剂,在助催化剂甲基铝氧烷(MAO)存在的条件下,催化乙烯齐聚。还利用核磁共振氢谱、元素分析及质谱对配体及催化剂进行了结构表征。试验结果表明:镍系催化剂催化活性最高可达4.65×105g/(molNi.h),α-烯烃选择性达76.40%。     

新型双核α-苊二亚胺镍催化剂合成及其催化乙烯聚合

通过控制schiff碱缩合反应合成了三个桥联的α-苊二亚胺,进一步与无水氯化镍反应得到了新型双核桥联α-苊二亚胺镍催化剂,配体与催化剂经过1HNMR和质谱表征。在甲基铝氧烷(MAO)的存在下,显示出较高的催化活性,所得聚合物经GPC,DSC,13CNMR表征,结果显示聚合物具有较高的分子量,较低的熔点,以及较高的支化度。     

新型的α-二亚胺Ni(Ⅱ)配合物的合成及催化乙烯聚合研究

设计并合成了一种新型的含有大体积基团phenyl的α-二亚胺配体1a及其Ni(Ⅱ)配合物1b,采用NMR谱、XPS对其进行了表征。研究了聚合条件如Al/Ni摩尔比、聚合反应温度及配体结构等因素对催化剂活性的影响。在反应温度为5℃,Al/Ni摩尔比为800时,该催化体系催化乙烯聚合的活性最高,可达5.57×106g PE/(molNi·h·bar),所得聚乙烯具有较高的支化度,最高可达136 branches/1000C。采用1H NMR、DSC、GPC、TG分别对聚合物进行了表征。     

Synthesis and characterization of first‐ and second‐generation polyamide pyridylimine nickel dihalide metallodendrimers and their uses as catalysts for ethylene polymerization

First‐ and second‐generation pyridylimine‐terminated dendrimeric ligands were prepared by the reaction of the corresponding amine‐terminated aromatic polyamide dendrimers with 2‐acetylpyridine. The pyridylimine terminal groups were used as bidentate N,N ligands of nickel halide to prepare the corresponding first‐generation and second‐generation nickel dihalide metallodendrimers C1 and C2 , respectively. The synthesized dendrimers and metallodendrimers were characterized by elemental and spectral analyses. C1 and C2 were evaluated as catalyst precursors for ethylene oligomerization after being activated with methylaluminoxane (MAO) and diethylaluminum chloride (Et₂AlCl) under 1 atm and 5 atm pressure of ethylene. In both cases, the use of 1 atm or 5 atm pressure of ethylene and a 1500:1 Al:Ni molar ratio for C1 and C2 resulted in high catalytic activities toward ethylene polymerization. Upon activation with MAO and Et₂AlCl, C1 exhibited promising activities toward ethylene polymerization and produced linear chain structures that were associated with high density polyethylene. In contrast, C2 produced a polymer with the branching nature of low density polyethylene under similar conditions. © 2014 Society of Chemical Industry     

Vinyl polymerization of norbornene with bis(imino)pyridyl nickel(II) complexes

A series of different steric hindrance nickel(II) complexes 1 – 6 bearing 2,6‐bis(imino)pyridine ligands have been synthesized and characterized. The molecular structures of the complexes 3 – 5 were determined by X‐ray diffraction analysis. The coordination geometry around the nickel center of the complexes is either square pyramid for complexes 3 and 4 or trigonal bipyramid for complex 5 . All of the nickel complexes exhibit high catalytic activity for norbornene polymerization in the presence of MAO, although low activity for ethylene oligomerization and polymerization. The effects of the Al/Ni ratio, halogen, monomer concentration, temperature, and reaction time on activity of catalyst for norbornene polymerization and polymer microstructure were investigated. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2009     

Bimodal polyethylene promoted by novel nickel complex

A novel nickel complex, bis[2‐methyl‐2,4‐bis(2′‐pyridyl)‐1H‐1,5‐benzodiazepine]nickel dichloride, displayed good activity for oligomerization and polymerization of ethylene with the assistance of a co‐catalyst, methylaluminoxane (MAO). The oligomers were mainly olefins from C₄ to C₁₀, while the highly branched polyethylene (PE) had molecular weights (M_w) in the range 19 000–34 000. Bimodal distributions of the PE were clearly observed by both DSC and GPC measurements, while the spherulitic structure of the PE was shown in the morphology. Copyright © 2004 Society of Chemical Industry     

超支化镍系催化剂构效关系及催化乙烯齐聚机理

采用1.0G超支化大分子（1.0G）、3-取代水杨醛和NiCl₂·6H₂O为原料,依次经席夫碱反应和络合反应合成了3种新型具有不同取代基位阻的超支化水杨醛亚胺配体及其镍系催化剂,利用红外光谱（FTIR）、核磁共振氢谱（¹H NMR）、紫外光谱（UV-vis）、电喷雾质谱（ESI-MS）及电感耦合等离子体质谱（ICP-MS）等方法对合成出产物的结构进行表征。考察了配体空间位阻、溶剂种类、助催化剂种类及反应条件对催化乙烯齐聚性能的影响。研究结果表明,配体空间位阻对催化乙烯齐聚性能有较大的影响,当以甲苯为溶剂、甲基铝氧烷（MAO）为助催化剂,在最佳反应条件下,超支化邻苯基水杨醛亚胺镍系催化剂催化乙烯齐聚的活性为2.81×10⁵g/(mol Ni·h),对高碳烯烃（C₁₀₊）的选择性为34.28%。此外,在超支化水杨醛亚胺镍系催化剂催化性能评价的基础上,对其催化乙烯齐聚的机理进行研究。     

Electron microscopic characterization of Cr/silica catalyst for ethylene polymerization

Ethylene polymerization was carried out over both porous and non-porous 5 wt% Cr/silica catalysts in a slurry reactor. The polymerization was stopped at selected times to obtain samples for SEM and TEM characterization. Despite the different physical characteristics of the two silica-supported catalysts and their different behavior in the early stages of reaction, high resolution SEM micrographs (taken after runs of longer duration) revealed similar, fibrous and very porous polymer layers on both. This accessibility of the ethylene enables transport of monomer to the active sites at the very high reaction rates.     

Imine-linked covalent organic frameworks coordinated with nickel for ethylene oligomerization

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 × 10⁵ 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.     

亚乙基苊镍催化剂催化乙烯溶液聚合制备超支化聚乙烯

以一种亚乙基苊(α-二亚胺)镍配合物为主催化剂,研究了温度、压力、助催化剂及其用量等对乙烯溶液聚合制备超支化聚乙烯(HBPE)的影响,并对HBPE的结构与性能进行分析.结果表明:随着温度或压力的升高,催化剂活性均呈现先升高后下降的趋势;HBPE的相对分子质量随温度的升高而下降,而支化度与温度呈正比,与压力呈反比;二氯乙...     

茂锆金属催化剂催化乙烯聚合研究

主要考察了含锆的茂金属催化剂中催化乙烯反应条件优化研究,在最优条件下催化聚合反应所得的产物与吉林石化公司聚乙烯厂聚乙烯产品进行分析对比.对茂锆金属催化剂催化乙烯聚合反应条件研究表明,适宜的助催化剂[Al]与主催化剂[Cat]的摩尔比在1 500左右,适宜的主催化剂浓度在1.5×10-4 mol/L左右,最佳聚合温度60℃,此时催化剂的活性可达到106 gPE/(molCat·h).从物理性能、热性能、相对支化度、相对分子质量及其分布分析可知,制备出的负载茂锆金属催化剂在最优反应条件下催化乙烯聚合所得的产物与吉林石化公司聚乙烯产品性质基本一致,符合产品的指标,支链分布均匀,分子量分布更窄.同时对茂锆金属催化剂主、助催化剂催化乙烯聚合的作用和机理进行了探讨.     

新型高氢调敏感性乙烯淤浆聚合用催化剂的制备

制备了一种新型高氢调敏感性乙烯淤浆聚合用催化剂(简称SEL催化剂)。考察了SEL催化剂的组成、粒子形态,催化乙烯均聚合与共聚合的性能,以及用其制备的聚乙烯的性能,并与商业化的同类型进口催化剂(简称参比催化剂)进行了对比。结果表明:SEL催化剂中钛含量高而镁含量低,粒径分布窄,颗粒形态规整;SEL催化剂催化乙烯聚合时氢调敏感性好,氢气分压为0.48 MPa,乙烯分压为0.25 MPa时,聚乙烯熔体流动速率达226.10g/10 min;SEL催化剂催化乙烯与1-己烯共聚合的性能和聚乙烯粉料中细粉含量等均优于参比催化剂。