用苯氧基亚胺型ⅣB族催化剂制备高附加值聚烯烃材料

苯氧基亚胺型前过渡金属烯烃聚合催化剂是近年来发展起来的一种非茂前过渡金属烯烃聚合催化剂。该类催化剂由于具有催化烯烃聚合活性高、结构可调性强、制备的聚合物可控性好等特点,受到了广泛的关注。本文综述了此类催化剂的设计合成,介绍了FI主催化剂上不同取代基对催化剂活性、分子量的影响以及采用不同助催化剂条件时催化剂表现出来的特殊性能,重点介绍通过调节配体上取代基、助催化剂以制备不同种类的高附加值聚烯烃材料。     

[N,N]-二齿镍配合物催化烯烃聚合

烯烃聚合催化剂的设计是烯烃配位聚合领域的一个核心科学问题,通过设计合成精确结构的催化剂可以有效地调控催化聚合性能以及聚合产物的结构.后过渡金属催化剂由于其易调变性、对聚合产物支化结构的可控性及对极性单体的容忍性,在烯烃聚合领域引起了广泛的关注.本文介绍了近年来本课题组在[N,N]-二齿镍烯烃聚合催化剂设计方面的研究进展,包括四元环的中性脒基镍催化剂、五元环的-二亚胺镍催化剂、2-胺基吡啶和-胺基亚胺系列镍催化剂,以及六元环的-二亚胺和苯胺基亚胺镍催化剂在烯烃聚合的应用.通过优化后过渡金属镍催化剂结构,可成功实施烯烃活性聚合.     

过渡金属络合物催化乙烯齐聚

综述了乙烯齐聚的最新成果,重点阐述了用于乙烯齐聚的新型催化剂,讨论了烯烃高聚与齐聚催化剂的关系,烯烃高聚与齐聚的反应机理相同,。差别主要在于烯烃插入与β－H消除反应的速率,第IV副族金属络合物主要催化乙烯齐聚,第Ⅲ副族金属主要催化乙烯高聚,改变茂金属催化体系的助催化剂和反应条件可得到齐聚产物,选择体积较小配体的第Ⅷ族金属络合物,有利于β－H消除得到齐聚产物。     

(η6-Arene)Nd(AlCl4)3-AIR3催化丁二烯的聚合

关于η~6-芳烃过渡金属有机络合物催化烯烃聚合的研究已早有报道.但对于η~6-芳烃稀土络合物催化烯烃聚合的研究至今未见报道.我们在研究了(η~6-C_6H_6)Nd-(AlCl_4)_3-AlR_3催化异成二烯聚合的基础上,又考察了不同芳烃烯土络合物和几种AlR_3组成的催化剂对丁二烯聚合的催化活性. 1.原料及试剂:丁二烯和烷基铝均为聚合级.汽油分别经浓硫酸,氢氧化钠水溶     

仿生催化剂——Salen金属络合物催化不对称环氧化烯烃的基础

Salen与卟啉、Salen金属络合物与卟啉铁的结构和性质相似, 因此可将Salen金属(Salen-M)络合物认为是仿生催化剂, 它们的仿生性突出表现在不对称催化反应中的高对映异构选择性. 重点介绍了Salen-M络合物催化环氧化烯烃的反应机理, 环氧化合物的对映选择性与Salen配位体中的取代基效应(以取代常数σ_p表示)之间呈线性关系. 另外, 对映异构选择性的高低还与催化剂配体和底物的结构以及反应条件有关.     

新一代单活性中心聚烯烃催化剂--水杨醛亚胺基过渡金属化合物

对新型的单活性中心聚烯烃催化剂——以水杨醛亚胺基配体稳定的后过渡金属络合物和前过渡金属络合物催化的结构性能特点、设计合成方法等做了较说尽的评述。     

水相配位催化烯烃聚合的新进展*

水相催化研究已经成为近年来化学反应研究的热点课题.烯烃聚合领域中水相自由基乳液聚合和悬浮聚合等方法早已工业化,而前过渡金属烯烃聚合催化剂对水气敏感,水相烯烃配位聚合发展缓慢.低亲氧性、高活性的后过渡金属烯烃聚合催化剂的出现使水相催化成为可能.本文综述了后过渡金属催化剂水相催化烯烃配位聚合的一些新进展,内容包括乙烯、α-烯烃、环烯烃、二烯烃的聚合反应和环烯烃的开环聚合反应以及CO/烯烃的共聚反应等方面.     

高分子钯络合物催化的亚胺化合物的加氢反应

制备了一系列以二氧化硅为载体的侧链上含有各种氮配位基团的聚硅氧烷-钯络合物,这些高分子钯络合物能够在常温常压下催化亚胺化合物的加氢反应并表现出不同程度的催化活性.对其中聚-(N,N-二乙酰基)-γ-氨丙基硅氧烷-钯络合物催化的亚苄基苯胺的加氢反应做了比较深入的研究,发现该催化剂在反应中是稳定的并给出唯一的加氢产物,络合物中的N/Pd原子比、反应温度以及不同底物对反应速度的影响也被报道.     

亮点介绍

铁催化的烯烃硼氢化反应Angew.Chem.Int.Ed.2013,52,3676～3680烷基硼试剂是一类非常重要的有机合成中间体,而烯烃的硼氢化反应是生成硼试剂的重要途径.在过去的三十年里,过渡金属催化的烯烃硼氢化反应已经取得了丰硕的成果.但大部分体系涉及Rh,Ir,Ru和Pd等贵金属催化剂.近年来,以铁为代表的第一周期过渡金属元素在均相催化领域得到广泛发展,例如,铁络合物在烯烃氢化和硅氢化方面显示出优秀的催化效能.中国科学院上海有机化学研究所黄正课题组最近实现了铁催化的烯烃硼氢化反应,他     

丙烯基水杨醛亚胺镍系聚烯烃催化剂

后过渡金属;烯烃聚合;烯丙基取代配合物;丙烯基水杨醛亚胺镍系聚烯烃催化剂     

镍配合物催化乙烯齐聚和聚合的进展

继SHOP催化体系采用镍配合物催化乙烯齐聚制备端烯烃在研究和应用中获得成功以来,由于后过渡金属上容易产生β-氢消除反应,镍配合物催化乙烯的研究搁置了近二十年。然而,近十年里,镍配合物催化乙烯齐聚和聚合研究再次受到催化剂研究者的重视,进入了飞速发展的新时期。本文综述近三年间这个领域的发展,特别是我国学者在这个领域的贡献,展示了镍配合物在乙烯齐聚和乙烯聚合制备支化聚烯烃中的巨大潜力,促进该领域研究的发展。     

Selective ethylene oligomerization bearing hyperbranched bispyridylamine chromium catalyst

Two new hyperbranched bispyridylamine ligands and multinuclear chromium complexes were synthesized with 1.0?G hyperbranched macromolecules, 2-chloropyridine, 2-chloro-4-methylpyridine and CrCl₃(THF)₃ as raw materials. The structures of hyperbranched ligands and chromium complexes were characterized by UV, FT-IR, ¹H NMR, ESI-MS, and elemental analysis. These hyperbranched chromium complexes were evaluated as catalyst precursors by using MAO as activator in the oligomerization of ethylene. Effects of reaction temperature, reaction pressure, Al/Cr molar ratio, concentration of catalyst, solvent, and the structure of catalysts on the catalytic activity and product selectivity were investigated. The oligomerization results showed that with increase of reaction temperature, reaction pressure, and Al/Cr molar ratio, the catalytic activity increased and then decreased; the catalytic activity continuously decreased as the amount of catalyst increased. The products were mainly based on C₆ and C₈. Under optimized conditions, the catalytic system of hyperbranched NNN/Cr(III)/MAO led to activity of 1.26?×?10⁵ g/(mol·Cr·h) and 63.34% selectivity for C₆ and C₈.     

Reactivity of group 4 benzamidinate complexes towards mono- and bis-substituted silanes and 1,5-hexadiene

Zirconium and titanium bis(benzamidinate) dimethyl complexes were found to be active catalytic precursors for the oligomerization of mono- and bis-substituted silanes. The activation of such complexes, by an excess of MAO or by an equimolar amount of B(C₆F₅)₃, increases the catalytic activity of the complexes and the molecular weight of the obtained oligosilanes. The maximum polymerization index that was accomplished (n = 90) is by far the largest obtained with other organometallic complexes. In addition, the activated benzamidinate catalysts were also found to be active for the polymerization of 1,5-hexadiene producing poly(methyl-1,3-cyclopentane). For the latter, the results obtained with C₂-symmetry bis(benzamidinate) dimethyl complexes were compared with a chiral complex bearing a myrtanyl group at the benzamidinate ligand.     

Influence of electronic effect on catalytic activity of salicylaldiminato nickel(II) complexes

A means of correlation between the activity and the net charge, the metal atom net charge correlation (MANCC), which was successful in the activity prediction of the early‐transition metal catalysts, has been used to study the catalytic activities of salicylaldiminato Ni(II) complexes, the late‐transition metal catalysts, in olefin polymerization or oligomerization. A comparison with the available quantum mechanics/molecular mechanics (QM/MM) calculation data suggests that even without a detailed mechanism, MANCC results mostly agree with QM/MM calculation data regarding insertion barrier data and enthalpy change. Eight experimental complexes were further built up by modeling; their catalytic activities predominantly increased in line with the net charges on the metal atoms. The same results were obtained for the other four complexes synthesized in the present work. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4765–4774, 2004     

Zirconium Catalyzed Ethylene Oligomerization

A review of the scientific and patent literature on oligomerization of ethylene to linear olefins in the presence of homogenous or heterogeneous zirconium complexes and various aluminum organic compounds has been fulfilled for last twenty-five years. Over these years, a wide range of studies had been conducted for selective oligomerization of ethylene into a narrow fraction of linear α-olefins such as C₄-C₈ and C₆-C₁₀ fractions. During the discussion of these catalytic systems, exceptional attention is also paid to feature works such as the activity of the catalysts and the acquisition of clear liquid product without any trace of polymer, all of which play important roles in the selection of the best technology.     

Prospects and crucial problems in oligomerization and polymerization with iron and cobalt complex catalysts

<正>The discovery of highly active 2,6-bis(imino)pyridyl iron and cobalt complexes provided a milestone of latetransition metal catalysts for ethylene oligomerization and polymerization with being currently investigated for the scale-up process.The crucial problems are remaining in the catalytic systems:the catalytic systems targeting ethylene polymerization produce more oligomers at elevated reaction temperatures,however,there is a recognizable amount of high-molecular-weight polyethylene remained in the modified catalytic system for the oligomerization process.Beyond the modification of bis(imino)pyridyl metal complexes,several alternative procatalysts' models have been developed in our group.This review highlighted the achievements in exploring new iron and cobalt complexes with tridentate NNN ligands as procatalysts for ethylene oligomerization and polymerization.     

乙烯齐聚合成线性 α-烯烃镍系催化剂

利用SHOP型工艺由乙烯齐聚制备线性α-烯烃不仅具有工业应用价值，而且具有很高的学术意义。SHOP型工艺的工业化引起了人们对基于P^∩O配位型及其他配位型镍催化剂的广泛的研究兴趣。镍系催化剂具有活性高、选择性好、产品分布可调、反应条件温和等优良性能。本文介绍了镍系催化剂的类型和性能等，并对影响催化性能的因素进行了分析。     

Direct synthesis of hyperbranched ethene oligomers and ethene-MA co-oligomers using iminopyridyl systems with weak neighboring group interactions

The synthesis of hyper-branched ethene oligomers through catalytic insertion reactions with late transition metal catalysts is unique in its synthetic and practical scope. In this study, a series of iminopyridyl Ni(II) and Pd(II) complexes with electron-rich distal aryl motifs were synthesized and characterized. These complexes were very efficient in ethene oligomerization and co-oligomerization with methyl acrylate (MA). Hyperbranched ethene oligomers with different microstructures were generated using different metal species in ethene oligomerization. More importantly, hyperbranched ethene-MA co-oligomers with varying incorporation ratios were generated via ethene and MA co-oligomerization using the Pd(II) complexes. Most notably, weak neighboring group interactions of distal aryl motifs in the nickel system are more effective in influencing the microstructure of ethene oligomers than the corresponding palladium system.     

Ethylene polymerization promoted by nickel complexes

The nickel complexes are of special relevance to catalysis for ethylene oligomerization and polymerization. Beyond the famous commercial SHOP process for ethylene oligomerization, among recent progress of nickel catalysts, various nickel complexes containing different ligands such as the bidentate and tridentate ligands are of interest. In contrast to the importance of hetereogeneous catalysis, the homogeneous catalyst is a small share for polyolefins, while the well-defined complexes affect the microstructure of the resultant polyolefin. The nickel catalysts often perform ethylene activations for inner olefins and the branched polyethylene with broad or bimodal molecular weight distribution. The catalytic behavior will be affected by adaptation of ligands coordinating around the nickel center. In addition, the auxiliary ligand Ph₃P can improve the catalytic activity by one order of magnitude, and its active center can be confirmed through isolating and characterizing the reliable intermediate. The text was submitted by the authors in English.     

镍配合物催化乙烯低聚/聚合的研究进展

催化乙烯低聚或聚合的镍配合物催化剂研究,不仅帮助提供探索乙烯配位聚合机理的催化剂模型,更为重要的帮助探讨不同催化剂模型下的催化剂活性和选择性,为工业界寻找具有潜在应用价值的高效催化剂奠定基础.同时,利用镍配合物催化剂容易导致所得聚烯烃树脂产生支链的特点,有望制备具有优异性能的支化聚烯烃树脂.本文综述了近年来镍配合物在乙烯低聚或聚合催化剂研究方面的进展,并特别强调了催化剂结构和催化性能之间的内在规律.