茂金属催化剂负载化及负载机理的研究进展

总结了茂金属催化剂负载化、栽体种类和负载方法,评述了茂金属催化剂负载机理的研究方法和研究状况。指出将实验方法和计算机分子模拟方法二者结合起来,能够加快研究进程。     

载体型茂金属催化剂

对载体型茂金属催化剂研究进展进行了评述,讨论了茂金属催化剂载体化方法,载体和茂金属载体化对催化剂性能和聚合物性质的影响以及各种载体型茂金属催化剂对烯烃聚合的催化行为,还简要介绍了生产双峰分子量分布聚合物的双金属催化剂。     

Mathematical Modeling of Homopolymerization on Supported Metallocene Catalysts

Summary: In this paper, a mathematical model describing olefin polymerization with metallocene catalysts is presented. It is an improvement of a previous model, the “particle growth model” (PGM) proposed by, among others, one of the authors of the present work and derives from the so‐called “multigrane model” (MGM). The main differences between this work and others is a more sophisticated approach to fragmentation with respect to the MGM. Additionally, there is a more specific modeling for the unfragmented core with respect to the PGM. The numerical results obtained by the model are compared with experimental data. The results of this work allow to extend the PGM to catalysts with lower activity. The importance of those catalysts depends on the fact that high activity catalysts could bring, in some cases, too poor polymer morphology.

Geometrical representation of the micro‐ and macroparticle.     

SiO2载体茂金属催化剂研究述评

由于SiO2载体茂金属催化剂在烯烃领域应用广泛，对SiO2载体茂金属催化剂的几种负载方式以及这几种负载方式的机理进行了详细介绍，列举了SiO2载体茂金属催化剂在烯烃聚合反应中的应用，阐述了SiO2载体焙烧温度、负载方式、载体表面改性对催化剂性能的影响。     

茂类金属催化剂用于苯乙烯聚合

概述了茂类金属催化剂用于苯乙烯均聚及共聚合的现状。     

茂金属催化剂及其应用

介绍了茂金属催化剂的结构、特点其及在聚烯烃领域的应用。     

Surface Model for Gas-Phase Polymerizations of Ethylene and Propylene Using Supported Metallocene/Methylalumoxane Catalysts

In order to obtain more detailed information about supported metallocene/methylaluminoxane catalysts, two catalysts are supported onto a flat silicon wafer by spincoating impregnation. These model catalysts are characterized by SEM and EDX showing a film of metallocene catalyst dispersed inside the methylaluminoxane matrix, as well as regions of a localized increased concentration of the catalyst. Applying these model catalysts in a gas-phase polymerization reactor results in rather homogeneous films of polyethylene and polypropylene, respectively. In addition, crater-like and spherical polymer structures can be observed, probably formed by inhomogeneous catalyst distribution.     

茂金属催化剂载体化研究进展

介绍茂金属催化剂负载的活性中心的形成机制，详细阐述了几种载体的负载方法和特点，阐述了表面处理剂对烯烃聚合的影响，概括了茂金属负载化后的特点，并对茂金属催化剂负载化的研究方向进行了展望。     

负载型茂金属催化剂的研究进展

茂金属负载化是拓宽其使用范围、降低其使用成本、改善聚合产物形态的有效手段。文章介绍了茂金属在SiO2、沸石、聚苯乙烯等载体上的负载方法、负载机理,综述了负载型茂金属催化剂在催化烯类单体聚合方面的应用,指出了今后的改进方向。     

茂金属催化剂的应用进展

本文叙述了茂金属催化剂近年的开发和应用概况, 包括在聚乙烯、聚丙烯、聚苯乙烯等领域的开发动向     

茂金属催化剂负载化研究进展

综述了近年来茂金属催化剂负载化的研究进展。通过研究烯烃聚合中载体的应用对催化剂性能和聚烯烃形态的影响,进一步说明了负载的目的和必要性。     

茂金属催化剂及烯烃齐聚物研究进展

21世纪是全新的科学技术时代,茂金属聚合物是化学工业中新型树脂产品,其产品开发进展很快。本文综述了近些年茂金属催化剂的发展状况,系统的介绍了茂金属催化剂的主要特征和优势,并对茂金属烯烃聚合物的加工和应用情况进行了阐述。     

Comparison of Olefin Polymerization Processes with Metallocene Catalysts

Summary: Solution and gas phase processes of the polymerization of ethene are compared using new types of pentalenyl bridged ansa‐metallocenes such as [Me₃Pen(Flu)]ZrCl₂. As of the bridge, the catalyst system is remarkable thermostable up to 105 °C and a deactivation of the metallocene on the silica support can be suppressed. Compared to the non‐supported catalyst in a solution process, the application of the heterogenized system in a gas phase process leads to a decrease in activities while molar masses of the polyethenes are similar. Due to a higher degree of short chain branches of 20–30 per 1 000 carbon atoms instead of 10–17, the melting temperatures are 10 °C lower than those for polymers obtained in the solution process.

Basic structure of the here used pentalenyl bridged ansa‐metallocenes.     

茂金属聚乙烯催化剂工业应用研究

北京化工研究院合成了50余种新型茂金属化合物,在茂金属催化剂均相乙烯聚合的系统研究基础上,深入研究了载体茂金属催化剂的制备方法和制备条件等因素与载体催化剂性能的关系,研制出性能优异的载体茂金属催化剂。采用载体茂金属催化剂进行了浆液法和气相法乙烯聚合中试研究,还进行了茂金属聚乙烯树脂的加工应用研究,树脂性能与国外同类产品相当。     

分子量宽峰分布聚乙烯茂金属催化剂的研究

以复合茂金属催化剂和双载体茂金属催化剂乙烯聚合、考察聚乙烯（ＰＥ）分子量分布变化情况。结果发现两者都使ＰＥ分子量分布加宽,其中复合茂金属催化剂Ｃｐ２ＺｒＣｌ２／ＹＢ３使分子量分布从２．３７增至９．１８。分子量分布增加幅度与不同复合茂经剂、催化剂配比、２载体量之比负载催化剂用量有关。     

双核茂金属催化剂催化乙烯／1-己烯共聚合

制备[CpTiCl2]2{μ,μ-[(Me2Si)2(η5-C5H3)2]}双核茂金属化合物,用1H NMR和IR分析进行了表征.合成的化合物经硅胶作载体负载,以MAO作助催化剂,催化乙烯/1-己烯共聚合.考察了茂金属用量,茂金属与硅胶/MAO处理温度,MAO的用量对负载催化剂的影响,以及己1烯-用量对聚合产物的影响.反应温度65℃,在1-己烯浓度为0.25mol/L条件下共聚活性可达4.01× 106gPE/molTi·h,催化所得聚乙烯的相对分子质量分布为7.32,己1烯-插入率8.45.     

茂金属乙丙弹性体技术进展

论述了茂金属乙丙弹性体的合成、表征、反应机理及工业化进程,着重介绍了茂金属催化体系和茂金属乙丙弹性体的结构和性能。     

聚苯乙烯载体负载茂金属催化剂的合成及表征

合成了聚苯乙烯负载的茂金属催化剂,考察了硅胶用量、二乙烯基苯与苯乙烯体积比、洗涤温度和洗涤次数对催化剂的影响,并对其进行了表征.确定硅胶加入量为1 g,二乙烯基苯与苯乙烯体积比为0.08,洗涤温度60℃,洗涤次数为4次;XPS表征证明合成了聚苯乙烯载体茂金属催化剂.     

Investigation on Decomposition Kinetic and Thermal Stability of Metallocene Catalysts

Data on thermal stability of metallocene catalysts such as bis(n-butyl cyclopentadienyl) zirconium dichloride and bis(t-butyl cyclopentadienyl) zirconium dichloride is required because of their application in high temperature polymerization process. In the present study, the thermal stability of the bis(n-butyl cyclopentadienyl) zirconium dichloride and bis(t-butyl cyclopentadienyl) zirconium dichloride was determined by differential scanning calorimetry (DSC) and simultaneous thermogravimetry-differential thermal analysis (TG-DTA) techniques. The results of TG analysis revealed that the main thermal degradation for the bis(n-butyl cyclopentadienyl) zirconium dichloride and bis(t-butyl cyclopentadienyl) zirconium dichloride occurs in the temperature ranges of 194–360 °C and 195–350 °C, respectively. On the other hand, TG-DTA analysis indicated that bis(n-butyl cyclopentadienyl) zirconium dichloride melts (about 98.7 °C) before it decomposes. However, the thermal decomposition of the bis(t-butyl cyclopentadienyl) zirconium dichloride was started simultaneously with its melting. Also, the kinetic parameters such as activation energy and frequency factor for both compounds were obtained from the DSC data by non-isothermal methods proposed by Kissinger and Ozawa. Based on the values of activation energy obtained by Kissinger and Ozawa methods, the following order for the thermal stability was noticed: bis(t-butyl cyclopentadienyl) zirconium dichloride >bis(n-butyl cyclopentadienyl) zirconium dichloride. Finally, the values of ΔS^#, ΔH^# and ΔG^# of their decomposition reaction were calculated.     

Supported Organometallic Catalysts for Olefin Polymerization

The concept of the basic role of the transition metal-carbon bond in the catalytic polymerization of olefins was formulated in the early stages of the study of Ziegler-Natta catalysts (see Ref. 1). In this connection, attempts to use the individual organometallic transition metal compounds as catalysts for olefin polymerization have been made regularly when such compounds were synthesized[2-10]. Polymerization of ethylene in the presence of organometallic compounds containing -CH₃[2, 3], -C₆H₅[7], -CH₂C₆H₅[5, 6], -C₃H₅[4, 10], -CH₂-C(CH₃)₃[10], and -CH₂-Si(CH₃)₃[10] as organic ligands have been reported. In some cases such compounds were considered to be “models of the active centers.” However, considering the experimental results from this point of view led to a discrepancy with the following observations: