乙烯水相配位聚合反应的研究进展

综述了用于乙烯水相配位聚合反应的有机铑络合物、中性Ni(II)阴离子P-0配体络合物、中性Ni(Ⅱ)水杨醛亚胺配体络合物和阳离子α-二亚胺配体络合物的合成及所得的聚合物的特性以及Ni络合物催化的乙烯水相乳液聚合反应。水作为反应介质具有很好的应用前景。水相聚合反应催化剂的研究今后将会成为聚烯烃催化剂研究的一个重要组成部分。     

茂金属均相催化剂研究进展

综述了用于烯烃聚合的茂金属均相催化剂的合成、影响催化性能的因素和催化作用机理,重点介绍了非桥连结构和桥连结构茂金属均相催化剂的催化行为。     

聚烯烃纤维

20073118PP非织造布用二茂金属络合物催化剂Fritze C.;Chemical Fibers International,2004,54(4),p.232(英)在2001年,Basell介绍了它最先进的催化剂体系:Avant。在这一系列中,Avant M基团包括了Basell在结构上定义的聚丙烯生产用锆基二茂金属络合物催化剂。Basell的Metocene等     

茂金属催化剂的研究进展

介绍了茂金属催化剂合成技术,重点阐述了非桥联型、桥联型、限定几何构型、离子型和负载型茂金属催化剂的合成、结构及性能。     

茂金属催化剂及其开发近况

茂金属(metallocene)是由过渡金属与环状不饱和结构茂环(即环戊二烯、C_5H_5~-、Cp)组成的配位有机金属络合物。金属常为铁(二茂铁)、钴(二茂钴),其他一些金属亦能形成这种结构。由于金属原子位于两个有机环中间,故有时称之为有机金属“三明治”。茂金属在50年代初第一次出现,它可用作汽油抗震剂、抗爆剂、催化剂和还原剂。     

FI催化剂在制备乙烯基共聚物中的应用

综述了带有芳氧基亚胺配体的ⅣB族金属络合物(FI催化剂)催化的乙烯类共聚合。Ti-FI催化剂可用于乙烯与α-烯烃、乙烯与环烯烃的共聚合。相比传统的茂金属催化剂,FI催化剂可以制备共聚单体含量更高的共聚物。FI催化剂对极性基团具有良好的耐受性,将其用于乙烯与极性单体的共聚合,可取得理想的效果。与亚胺N原子相连的芳香环上的邻位H原子被F原子所取代的Ti-FI催化剂催化乙烯类聚合时,表现出活性聚合的特征。因此可通过控制单体加入顺序制备嵌段共聚物。用两种不同的FI催化剂,且以二乙基锌为链穿梭剂,可制备多嵌段共聚物。优化配体结构可制备高效的乙烯类共聚合催化剂。这些将有利于实现聚烯烃的功能化和高性能化。     

茂金属聚丙烯催化剂概述

聚丙烯是一种生活中应用非常广泛的材料,其中丙烯聚合催化剂的进步是聚烯烃工业蓬勃发展的关键。具有独特性能和优势的茂金属聚丙烯催化剂在过去的几十年中引起了人们极大的研究兴趣。综述了茂金属聚丙烯催化剂的结构、组成,助催化剂以及茂金属催化丙烯聚合机理。重点介绍了非桥联茂金属催化剂以及桥联茂金属催化剂,其中桥联茂金属化合物因桥基的刚性骨架结构,使得其与聚丙烯规整度紧密相连。还详细介绍了C_2、C_(2v)、C_s、C_1不同对称性对聚丙烯规整度的影响。     

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。     

金属茂均相催化剂用于乙烯聚合的研究

研究金属茂均相催化剂中过渡金属的性质对乙烯聚合的影响。以丁烯基取代的二茂二氯化锆（ＣｐＢｕ）２ＺｒＣｌ２和丁烯基取代的二茂二氯化锆（ＣｐＢｕ）２ＨｆＣｌ２与甲基铝氧烷组成的均相催化剂体系，对乙烯聚合进行了较详细的比较研究。     

高效乙烯聚合催化剂的制备Ⅰ.催化剂的制备规律

研究了新型含镁络合物的结构、性质及其用于制备高效乙烯聚合催化剂的制备规律.结果表明:将镁、有机醇以及不与镁发生"格式反应"的卤代烷相互作用可迅速发生反应形成新型含镁络合物溶液.该络合物在溶液中可析出结晶,具有特定的化学结构,可以均匀承载于多孔硅胶的孔隙中,负载TiCl4后制备出形态良好的球形高效乙烯聚合催化剂.     

聚合物载体_稀土金属络合物催化剂催化双烯烃聚合的特征

对聚合物载体的合成、稀土金属化合物的固定和聚合物载体－稀土金属络合物的性质及其催化双烯烃聚合的特征进行了论述。     

乙烯聚合用树枝状过渡金属催化剂研究进展

树枝状过渡金属催化剂是在树枝状大分子上负载上过渡金属活性中心,因此,此类催化剂既具有树枝状大分子特有的艺术结构,同时还具有过渡金属配合物的功能化性能,使其两者能够协同发挥作用,兼具均相和非均相催化体系的特点,在催化烯烃聚合方面具有较高的催化活性和良好的催化稳定性,近年来备受关注,催化乙烯聚合就是其中的研究热点之一。本文按其过渡金属活性中心进行分类,综述了近年来国内外树枝状过渡金属催化剂在这乙烯聚合方面的进展,阐述了多种树枝状效应产生的原因,并且对乙烯聚合用树枝状过渡金属催化剂的发展前景进行了展望。     

国外合成橡胶工业近期发展简评

在评述世界合成橡胶工业技术发展趋势的基础上，指出：对现有ＳＲ技术的改进和完善；弹性体的改性技术向深层次发展；正离子聚合技术，橡胶合流技术、稀土催化聚合技术和高性能胶乳合成技术的开发；等等，是目前ＳＲ工业技术发展的方向，并已取得煤些实际进展。     

含膦氧配体的稀土配合物对Mannich反应的催化作用

在研究稀土金属氯化物对Mannich反应的催化作用基础上,进一步研究了部分稀土氯化物与单膦氧配体、三苯氧膦(Ph_3PO)以及两种双膦酸酯、四异丙基亚甲基双磷酸酯{(~iPrO)_2P(O)CH_2P(O)(~iPrO)_2=L]}及双二苯基膦氧甲烷{[Ph_2P(O)CH_2P(O)Ph_2]=dppmO_2}所形成的配合物对Mannich反应的催化作用。结果发现,膦氧配体与稀土氯化物的配合物的催化能力比相应的氯化物低,但GdCl_3和TmCl_3与L(物质的量比1:1)结合时所形成的配合物的催化能力没有下降。     

稀土高分子配合物发光材料的合成

发光稀土高分子配合物是一类很有价值的功能材料,本文就其3种合成方法进行评述。以稀土离子与含配位基团的聚合物进行反应,难以获得发光强度高的高分子配合物;使稀土离子与高分子配体和小分子配体同时作用,可以得到荧光强度比较理想的产物,但反应难以定量控制;以小分子稀土配合物单体进行聚合反应,也可获得荧光强度较高的高分子配合物,但聚合反应的空间位阻较大。并针对方法3提出了改进的思路。     

N,N-、N,P-配体镍络合物催化乙烯聚合研究进展

综述了以后过渡金属镍络合物为代表的,螯合N,N-、N,P-配体为催化剂催化烯烃聚合研究内容。对催化活性以及产物结构的影响进行了讨论,指出含N,N-、N,P-配体螯合的金属镍络合物催化剂催化乙烯聚合在这一领域的优势。     

Recent transition metal catalysts for syndiotactic polystyrene

Syndiotactic polystyrene has attracted much interest in scientific and industrial research after its first synthesis in 1985 and has led to a fast commercialization of this polymer. The catalyst systems used for this coordination polymerization of styrene are a key point in this development to provide high polymerization activities and syndiotacticities of the polymers obtained.This literature review gives a comprehensive overview on the recent transition metal catalysts comprising the literature since about 2000 and especially on the transition metal complexes investigated in the syndiospecific homopolymerization of styrene. It includes the polymerization activity of the catalysts, the syndiotacticity of the polymers received as well as the discussion of the relationships between catalyst structure and polymerization activity. The complex-coordination mechanism of the syndiospecific polymerization of styrene is summarized in general at the beginning.The review of the recent transition metal catalysts for the syndiospecific styrene polymerization includes transition metal complexes, cocatalysts (methylaluminoxanes and boron compounds), activators and chain transfer agents, and supported and heterogenized catalysts. Transition metal complexes contain group 4 transition metal complexes (mono- and bis-cyclopentadienyl complexes, metal complexes of other ring systems such as indenyl, fluorenyl and other complexes, di- and multi-nuclear complexes, and non-metallocene complexes), and metal complexes of other transition metals (groups 8–10, rare earth metals, and others). The chapter on mono-cyclopentadienyl complexes demonstrates an overview on the investigations using unsubstituted cyclopentadienyl and pentamethylcyclopentadienyl complexes, on the influence of the variation of the structure of the cyclopentadienyl ligand, and on the effect of the variation of ancillary complex ligands besides cyclopentadienyl.This summary also considers recent developments in the preparation of new transition metal complexes based on the synthesis of completely novel π-ligands of the half-metallocenes, the success in attaining high syndiospecificities with transition metal complexes based on rare earth metals, the coordination polymerization in aqueous systems, the syndiospecific living polymerization, and new activators for the catalysts, with regard to syndiotactic polystyrenes.     

Synthesis, characterization and olefin polymerization studies of iron(II) and cobalt(II) catalysts bearing 2,6-bis(pyrazol-1-yl)pyridines and 2,6-bis(pyrazol-1-ylmethyl)pyridines ligands

The complexes Py(PzR₃)₂MCl₂ (R = H, Me; M = Fe, Co) and Py(CH₂PzR₃)₂MCl₂ (R = H, Me; M = Fe, Co) have been synthesized, characterized and used in the ethylene polymerization. Treatment of these iron and cobalt complexes with methylaluminoxane (MAO) as cocatalyst leads to active ethylene polymerization catalysts that produced linear polyethylene. In general, iron catalysts were more active than cobalt analogs. The steric and electronic effects of the ligands were study over the catalytic activity toward ethylene polymerization. Complexes with small substituents groups (R = H) on the pyrazolyl ring, increase the catalytic activity in comparison to complexes with bigger substituents groups (R = CH₃). Additionally, complexes with methylene groups placed between pyridine and pyrazole rings of ligands have less catalytic activity than complexes without the methylene group (CH₂). The presence of methyl groups (R = CH₃) in iron and cobalt complexes allow to obtain polyethylene with molecular weights higher than the one obtained with complexes without these methyl groups. Additionally, complexes with methylene groups present between pyridine and pyrazole rings generate polyethylenes with molecular weight higher than the ones produced with complexes without these methylene groups.     

Copolymerization of ethylene/α‐olefins over (2‐MeInd)2ZrCl2/MAO and (2‐BzInd)2ZrCl2/MAO systems

Ethylene homopolymerization and ethylene/α‐olefin copolymerization were carried out using unbridged and 2‐alkyl substituted bis(indenyl)zirconium dichloride complexes such as (2‐MeInd)₂ZrCl₂ and (2‐BzInd)₂ZrCl₂. Various concentrations of 1‐hexene, 1‐dodecene, and 1‐octadecene were used in order to find the effect of chain length of α‐olefins on the copolymerization behavior. In ethylene homopolymerization, catalytic activity increased at higher polymerization temperature, and (2‐MeInd)₂ZrCl₂ showed higher activity than (2‐BzInd)₂ZrCl₂. The increase of catalytic activity with addition of comonomer (the synergistic effect) was not observed except in the case of ethylene/1‐hexene copolymerization at 40°C. The monomer reactivity ratios of ethylene increased with the decrease of polymerization temperature, while those of α‐olefin showed the reverse trend. The two catalysts showed similar copolymerization reactivity ratios. (2‐MeInd)₂ZrCl₂ produced the copolymer with higher M_w than (2‐BzInd)₂ZrCl₂. The melting temperature and the crystallinity decreased drastically with the increase of the α‐olefin content but T_m as a function of weight fraction of the α‐olefins showed similar decreasing behavior. © 2000 John Wiley & Sons, Inc. J Appl Polym Sci 75: 928–937, 2000     

Influence of the catalyst matrix structure of the supported Ziegler-Natta catalysts on the homo- and copolymerization of olefins

The vanadium catalytic complexes immobilized on the same support (aluminium hydroxide, AH) and distinguished by structure and composition have been compared for ethylene and propylene homo- and copolymerization to find relationship between the polymerization activity, copolymerization relative reactivity of comonomers and the supported catalyst structure. The catalytic complexes of vanadium with supported aluminoxanes (II) and catalysts with dispersed solid phase of vanadium compounds on the support surface (III) are more active than catalyst (I) in which vanadium has the covalent bond with surface of support. The relative reactivity of comonomers in copolymerization also depends on type of supported catalyst. The catalysts III unlike I and II can produce the ethylene and propylene copolymers with high content of propylene. The promoting effect of propylene on ethylene polymerization rate takes place only in the presence of catalysts III. Received: 2 October 1996/Revised: 17 January 1997/Accepted: 23 January 1997