非茂双核烯烃聚合催化剂研究和应用进展

综述了非茂双核烯烃催化剂近十年的研究进展。重点阐述了配体上各种取代基电子效应和空间结构与催化乙烯聚合性能关系,分析了双核非茂金属烯烃催化剂催化聚合特点,指出了烯烃聚合用双核非茂催化剂发展方向。     

应用光电子能谱对一种负载型非茂催化剂结构的表征

通过吡啶吸附红外光谱和光电子能谱对负载型非茂催化剂CpTi（dbm）Cl2的载体和催化剂的结构进行了表征,发现MgCl2／高岭土双载体表面存在大量强L酸中心;经双载体负载后的CpTi（dbm）Cl2中Ti 2p的电子结合能增加了0．6～0．65eV。分析结果表明,Mg对Ti的电子效应以及载体中MAO对CpTi（dbm）Cl2的预活化作用是促使负载后活性提高的重要原因。     

非茂金属络合物催化烯烃聚合研究进展

非茂金属络合物是近些年发展起来的高性能烯烃聚合催化剂,由非茂化合物作为配体与金属前体配位络合生成,以其极高的活性、聚合物分子结构的可控性、多重活性聚合等特性受到关注。综述了非茂金属络合物的研究进展,按照配体骨架和金属中心分类,阐述了非茂金属络合物催化烯烃聚合特性,为其深入研究及工业化应用提供参考。     

负载茂金属催化剂催化乙烯气相聚合

研究了负载茂金属催化剂(n-BuNeCp)_2ZrCl_2/SiO_2的乙烯气相聚合行为及其催化聚合产品的性能。三乙基铝加入聚合体系后可降低负载茂金属催化剂的初始活性,有利于聚合过程中的温度控制。气相聚合产品聚乙烯的重均分子量为(1 42～2.28)×10~5,相对分子质量分布为2.6～3.1,熔点在135℃以上,结晶度约为60%,聚乙烯产物颗粒形态以球形为主.堆密度大于0.35 g/cm~3。     

非茂金属烯烃聚合催化剂的载体化研究进展

综述了近年来非茂金属烯烃聚合催化剂的载体化研究的新进展。按照不同载体的分类,介绍了载体化非茂金属催化剂的制备方法及其表征,讨论并总结了载体化方法、聚合温度、助催化剂用量及种类、聚合压力等聚合条件对载体催化剂的催化烯烃聚合行为的影响,以及对所得聚合物相对分子质量、相对分子质量分布、熔点、形貌等性质的影响。     

有机铬催化剂催化乙烯聚合

研究了有机硅烷铬酸酯催化剂(简称有机铬催化剂)在乙烯气相均聚合小试中的催化性能和聚合动力学行为。考察了不同种子床制备方法、有机铬催化剂加入量、聚合温度、乙烯与氢气分压比对聚合的影响,并对聚乙烯(PE)进行了结构与性能的分析表征。结果表明:经热活化与化学活化处理后的硅胶表面基本不含羟基,适宜作为种子床使用;有机铬催化剂加入量在100.0~150.0 mg时其活性最高且保持稳定,聚合动力学曲线为快速上升缓慢下降型;聚合温度在80~100℃时有机铬催化剂活性最高且变化不大,但在110℃时下降;随聚合温度升高,PE的重均分子量与数均分子量均降低,且相对分子质量分布明显变窄;H2的加入会显著降低有机铬催化剂活性。     

几种过渡金属催化剂应用于乙烯的聚合

介绍了高分子聚合用的Ziegler-Natta催化剂、Philips催化剂以及茂金属催化剂的结构特点及聚合性能比较,论述了这些催化剂在乙烯聚合中的应用与发展以及所生成的聚乙烯的结构与性能。     

非茂双核烯烃聚合催化剂研究和应用进展(续)

综述了非茂双核烯烃催化剂近十年的研究进展。重点阐述了配体上各种取代基电子效应和空间结构与催化乙烯聚合性能关系,分析了双核非茂金属烯烃催化剂催化聚合特点,指出了烯烃聚合用双核非茂催化剂发展方向。     

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.     

后过渡金属催化剂催化乙烯聚合

考察了不同温度,Ａｌ／Ｆｅ比以及催化剂浓度等条件下后过渡金属ＦｅＭＡ催化剂乙烯常压聚合的催化活性和动力学行为。     

α-二亚胺镍溴化物/凹凸棒黏土负载催化剂催化乙烯聚合研究

A nickel-diimine catalyst [N, N'-bis(2,6-diisopropylphenyl)-1,4-diaza-2,3-dimethyl-1, 3-butadiene nickel dibromide, DMN] was supported on palygorskite clay for ethylene slurry polymerization. The effect of supporting methods on the catalyst impregnation was studied and compared. Pretreatment of the support with methylalumi-noxane (MAO) followed by DMN impregnation gave higher catalyst loading and catalytic activity than the direct impregnation of DMN. Catalyst activity as high as 5.42×105g PE·molNi-1·h-1 was achieved at ethylene pressure of 6.87×105 Pa and polymerization temperature of 20℃. In particular, the morphological change of the support during MAO treatment was characterized and analyzed. It was found that nano-fiber clusters formed during the support pretreatment, which increased the surface area of the support and favored the impregnation of the catalyst. The investigation of polymerization behavior of supported catalyst revealed that the polymerization rate could be kept at a relatively h     

Zeolite MCM-22 Supported Heterogeneous Chromium Catalyst for Ethylene Polymerization

The chromium alkyl complex Cp*Cr(py)Me₂ (Cp* = ⁵-pentamethylcyclopentadienyl, py = pyridine, Me = methyl) has been affixed to the surface of zeolite MCM-22 via methane elimination. The resulting composite material has been characterized by a variety of physical methods. The results are consistent with the presence of isolated organometallic fragments linked to the solid support by a covalent chromium–oxygen bond. Activation of this material with methylaluminoxane (MAO) yielded a highly active catalyst for the polymerization of ethylene. The polyethylene thus formed featured high molecular weights (M_w 4 × 10⁶) and narrow molecular weight distributions (M_w/M_n 3.5).     

铬系乙烯聚合催化剂研究进展

介绍了铬系乙烯聚合催化剂的类型、改性与发展。指出需对该类型催化剂的聚合反应机理作进一步研究。     

Late Transition Metal Catalyst Based on Cobalt for Polymerization of Ethylene

The late transition metal catalyst of [2,6-diacethylpyridinebis(2,6-diisopropylphenylimine)]cobalt(II) dichloride was prepared under controlled conditions and used for polymerization of ethylene. Methylaluminoxane (MAO) and triisobuthylaluminum (TIBA) were used as a cocatalyst and a scavenger, respectively. The highest activity of the catalyst was obtained at about 30°C; the activity decreased with increasing temperature. At polymerization temperatures higher than 50°C not only was a sharp decrease in the activity observed but also low molecular weight polyethylene product that was oily in appearance was obtained. The polymerization activity increased with increasing both of the monomer pressure and [MAO]:[Co] ratio. However, fouling of the reactor was strongly increased with increasing both of the monomer pressure and the amount of MAO used for the homogeneous polymerization. Hydrogen was used as the chain transfer. The activity of the catalyst and the viscosity average molecular weight (M_v) of the polymer obtained were not sensitive to hydrogen concentration. However, the viscosity average molecular weight of the polymer decreased with the monomer pressure. The (M_v), the melting point, and the crystallinity of the resulting polymer at the monomer pressure of 1 bar and polymerization temperature of 20°C were 1.2 × 10⁵, 133°C, and 67%, respectively. Heterogeneous polymerization of ethylene using the catalyst and the MAO/SiO₂ improved morphology of the resulting polymer; however, the activity of the catalyst was also decreased. Fouling of the reactor was eliminated using the supported catalyst system.     

新型高性能Ziegler-Natta催化剂用于乙烯淤浆聚合

A novel high performance MgCl2/TiCl4 catalyst with tetrabutyloxsilicane as electron donor was prepared for ethylene slurry polymerization process. The properties of the catalyst such as particle size distribution, catalytic activity, hydrogen responsibility and copolymerization performance were investigated and compared with commercial catalyst (imported catalyst). Copolymerization of ethylene and 1-butylene using the catalyst was stud-ied in a pilot plant. The composition, structure and property of the copolymer were characterized by 13C nuclear magnetic resonance (13C NMR) and gel permeation chromatography-Infrared (GPC-IR), and compared with those of the copolymer obtained from a commercial catalyst. In comparison with the commercial catalyst, the novel cata-lyst had a higher activity (up to 34.6 kg•g－1) and a better particle size distribution (PSD), and produced polymers having higher bulk density (up to 0.37 g•cm－3) with less fine resin. Meanwhile, the novel catalyst showed a higher hydrogen responsibility and better copolymerization performance. The results indicated that the copolymer obtained from the novel catalyst has a higher branch in the high molecular weight fraction and lower branch in the low mo-lecular weight fraction.     

Ti—Mg催化剂乙烯气相聚合反应研究

研究了乙烯气相聚合Ｔｉ－Ｍｇ催化剂的聚合性能，常压气相聚合催化效率７～１１ｋｇＰＥ／ｇＴｉ，产物表观密度０．３０～０．３３ｇ／ｍｌ，产物颗粒２０～１２０目重量占８９％～９７％，加压搅拌床气相聚合，催化效率６１～８１ｋｇＰＥ／ｇＴｉ，产物表观密度０．３４～０．３５ｇ／ｍｌ，产物颗粒１０～１２０目重量占９１％～９６％。流化床惭烯／１－丁烯共聚合催化效率１００～１６９ｋｇＰＥ／ｇＴｉ，ＭＩ２．１６＝５．     

Melamine-Formaldehyde-Supported Titanium-Based Heterogeneous Ziegler-Natta Catalyst for Ethylene Polymerization in Slurry Process

Ethylene was polymerized at 40°C temperature and 1 atm. pressure using melamine-formaldehyde (M-F) supported titanium tetrachloride (TiCl₄) catalyst. Polymer-supported catalysts were prepared with a different weight ratio of TiCl₄/ M-F in hexane. The wt% titanium incorporated in the polymer matrix was determined by UV-visible spectroscopy. In addition, the resulting catalysts were characterized by SEM-EDX, XRD, and TGA. The catalytic productivity is found to be 4721.09 g PE/g Ti/h. The productivity of the catalysts also depends on the titanium content in the polymer matrix. The catalyst with titanium content 3.5 wt% showed maximum activity. These catalysts also showed good storability.     

Ziegler催化剂铝／钛比对乙烯聚合反应的影响

按照乙烯聚合反应机理,论述了Ziegler催化剂铝/钛比降低,对乙烯聚合反应及产品性能的影响,并对所得结果进行了讨论。     

气相法铬系聚乙烯催化剂QCP-01的改进

从催化剂配方和制备工艺条件方面对QCP-01气相法铬系聚乙烯催化剂进行了改进,达到了适当降低催化剂聚合活性并提高聚合物熔融指数的目的。