苯氧乙酰基四羰基钴催化亚胺与一氧化碳交替共聚反应合成多肽类聚合物

报道了一种新的苯氧乙酰基四羰基钴催化剂, 并将其用于催化亚胺与一氧化碳的交替共聚反应. ¹H NMR分析结果表明, 该催化剂在1个大气压的CO气氛下以烷基钴和酰基钴平衡的形式存在. 催化反应结果表明, 该催化剂具有良好的催化性能, 可以得到具有较高分子量、 N端为苯氧乙酰基的多肽类聚合物, 且具有较窄的分子量分布. 利用核磁共振、 红外光谱和质谱等对多肽聚合物的结构进行了表征, 结果表明, 聚合物链终止端除了具有慕尼黑酮类结构的端基以外, 还存在酰胺类的端基, 并对后者的生成机制进行了解释.     

芳香醛亚胺与一氧化碳的交替共聚反应

以苯乙酰基四羰基钴作为催化剂,研究了对芳香醛亚胺与一氧化碳(CO)的交替共聚反应.采用6种芳香醛亚胺单体,分别与CO进行交替共聚反应,得到了6种新的多肽类聚合物.利用核磁共振谱、红外光谱、凝胶渗透色谱(GPC)及MALDI-TOF质谱等对聚合物的结构进行了表征.探讨了芳香醛亚胺苯环上取代基的位阻效应和电子效应对聚合反应的影响.结果表明,聚合物链终止端存在3种不同类型的端基,分别具有慕尼黑酮类结构、咪唑啉类结构以及酰胺类结构,对这些端基的形成机理进行了讨论.     

双金属氰化物配合物的制备、表征及催化性能

 制备了基于钴氰化锌的双金属氰化物配合物（DMC）催化剂，并\r\n用元素分析、X射线衍射和红外光谱等手段进行了表征，考察了催化剂\r\n的结构与组成对其催化活性的影响以及该催化体系催化环氧烷烃开环聚\r\n合的特点．结果表明，含ZnCl2和叔丁醇的非晶态DMC催化剂具有最高的\r\n催化活性．该催化体系使聚合物的分子量可控，不饱和度很低（＜14μ\r\neq／g），逐步聚合所得到的聚合物的分子量分布较窄（Mn／Mw＜1．4\r\n8）．13CNMR分析结果表明，甲基氧丙环均聚物的链结构具有无规立构\r\n的特点，且链节分布几乎都为头－尾方式．IR分析结果表明，甲基氧丙\r\n环－环氧乙烷共聚物的链结构是无规分布的．     

Zr掺杂对La(Ba)Zr_xCo_(1-x)O_(3-δ)钙钛矿催化N_2O分解性能的影响(英文)

采用溶胶凝胶法制备了Zr掺杂的钴基钙钛矿La(Ba)ZrxCo1-xO3-δ,并将其用于航天推进剂领域的高浓度N2O催化分解反应.发现Zr的引入明显提高了钙钛矿La(Ba)ZrxCo1-xO3-δ的催化活性,尤其是当Zr掺杂量分别为0.05和0.2时,LaZrxCo1-xO3-δ和BaZrxCo1-xO3-δ催化剂性能较为优异.应用N2物理吸附、X射线衍射、H2程序升温还原、O2程序升温脱附和氧脉冲吸附技术表征了Zr掺杂对La(Ba)ZrxCo1-xO3-δ催化剂的物化性质的影响.结果表明,Zr掺杂增大了钴基钙钛矿的比表面积,改善了晶格结构,从而提高了钴物种的还原及氧吸附脱附能力,因而催化剂上N2O分解活性增加.     

Zr掺杂对La（Ba）ZrxCo1-xO3-δ钙钛矿催化N2O分解性能的影响（英文）

采用溶胶凝胶法制备了Zr掺杂的钴基钙钛矿La(Ba)ZrxCo1-xO3-δ,并将其用于航天推进剂领域的高浓度N2O催化分解反应.发现Zr的引入明显提高了钙钛矿La(Ba)ZrxCo1-xO3-δ的催化活性,尤其是当Zr掺杂量分别为0.05和0.2时,LaZrxCo1-xO3-δ和BaZrxCo1-xO3-δ催化剂性能较为优异.应用N2物理吸附、X射线衍射、H2程序升温还原、O2程序升温脱附和氧脉冲吸附技术表征了Zr掺杂对La(Ba)ZrxCo1-xO3-δ催化剂的物化性质的影响.结果表明,Zr掺杂增大了钴基钙钛矿的比表面积,改善了晶格结构,从而提高了钴物种的还原及氧吸附脱附能力,因而催化剂上N2O分解活性增加.     

铁、钴金属配合物催化1,3-二烯烃聚合研究进展

1,3-二烯烃类单体聚合物性能优异，在橡胶工业中占据重要地位.以1,3-丁二烯为单体的顺丁橡胶在工业中可生产多种橡胶制品，以异戊二烯为单体的异戊橡胶因其结构与天然橡胶相似，在一些领域可替代天然橡胶. 1,3-二烯类聚烯烃材料的发展大大依赖于聚烯烃催化剂的不断创新.在过去的10年中，铁、钴催化剂因其原材料廉价、配位类型丰富、合成简便、性质稳定等优良特性受到了广泛关注.通过对催化剂的配体结构进行合理设计和调整，能控制聚合物的微观结构、分子量，从而改变聚合产物的性能.本文综述了近10年来铁、钴配合物催化1,3-二烯烃聚合的研究进展，详细讨论了催化剂结构对催化活性、聚合物分子量、聚合物微观结构和聚合物分子量分布的影响.     

(P^N^P)钴配合物/倍半氯化乙基铝催化苯乙烯聚合的研究

采用含氮双膦配体与无水氯化钴反应可制得一系列相应的(P^N^P)钴配合物,并研究了该系列钴配合物对苯乙烯聚合的催化性能.在助催化剂倍半氯化乙基铝(EASC)的活化下,该系列钴配合物对甲苯中的苯乙烯溶液聚合表现出高的催化活性(可达5.44×105g(PS)·mol-1(Co)·h-1).通过对不同苯乙烯单体用量、助催化剂用量(Al/Co摩尔比)、聚合温度以及催化剂的配体环境等的研究,详细考察了这些因素对聚合反应和聚合产物性能的影响.通过凝胶渗透色谱法(GPC)和核磁共振碳谱(13C-NMR)表征了所得聚合产物的分子量及分子量分布和微观结构,分析结果表明,所得聚苯乙烯具有较低的分子量(Mn=2000~5900)和较窄的分子量分布(1.75~2.05),其微观结构是无规的.     

[N^N^O]钴配合物催化丁二烯立体选择性聚合的研究

合成并表征了一系列带有[2-(4,5-二苯基-2-咪唑基)-1-苯亚胺基]苯酚配体([N^N^O]三齿配体)的二氯化钴配合物(1~4),并研究了这些配合物对丁二烯溶液聚合的催化性能.研究结果表明,助催化剂的种类对丁二烯聚合的催化活性和产物性能有显著的影响,倍半乙基氯化铝(EASC)为最佳的助催化剂.在EASC的活化作用下,该催化体系引发丁二烯单体聚合,15 min内丁二烯单体的转化率可达92.7%,产物聚丁二烯中顺式1,4-结构的含量高达97.4%.并详细研究了助催化剂的用量、聚合的温度、配体上不同取代基等对丁二烯聚合行为的影响,包括丁二烯单体的转化率、产物聚丁二烯的分子量与分子量分布及微观结构.通过凝胶渗透色谱法(GPC)对聚合产物的分子量及分子量分布进行了表征,核磁共振氢谱(1H-NMR)和碳谱(13CNMR)分析结果表明所得聚合物具有高的顺式1,4-结构含量(97%左右).     

新型钴酞菁接枝温敏聚合物的制备及性能

采用2,4,6-三氯-1,3,5-三嗪对四氨基钴酞菁进行改性,并以共价键接枝到聚N-异丙基丙烯酰胺上制得一种新型温敏性高分子催化剂——钴酞菁接枝温敏聚合物,并采用UV-Vis、TG等对其进行表征.对钴酞菁接枝温敏聚合物、温敏聚合物和小分子金属酞菁进行溶解性测试,结果表明与四氨基钴酞菁相比,所合成的钴酞菁接枝温敏聚合物能溶解于水和大多数有机溶剂,且该聚合物水溶液具有良好的温敏性,其最低临界溶解温度(LCST)为34.5℃.采用浊度法考察了不同比例的混合溶剂(乙醇/水、DMF/水)对LCST的影响,结果表明随着有机溶剂含量的增加,LCST先下降后升高,而当有机溶剂增加到一定程度时温敏性消失.本文还考察了钴酞菁接枝温敏聚合物对2-巯基乙醇的催化活性,结果表明随着温度升高,催化活性也不断提高,而当温度超过LCST时催化活性急剧下降,聚合物从溶液中析出.基于这些特性,该温敏聚合物负载酞菁作为一种新型的催化剂可实现均相催化、异相分离.     

含超微氧化亚钴颗粒Beta分子筛的合成及其催化乙苯氧化性能

杂原子分子筛是指在硅铝分子筛或磷铝酸盐分子筛中含有骨架内或骨架外某种原子或其化合物的分子筛.这些杂原子可以是某些主族元素(如硼、锗、镓)或有变价特性的过渡金属元素(如钛、铁、钴、镍)等.将杂原子或其化合物通过浸渍、离子交换、水热晶化等方式引入沸石分子筛骨架中形成杂原子分子筛,往往可以改变沸石分子筛的骨架结构和理化性能,并赋予沸石分子筛新的催化反应性能.自1983年钛硅分子筛TS-1被发现能够高效催化烯烃环氧化以来,许多杂原子分子筛因其在催化烷烃类及芳烃类氧化、醛酮选择氧化及烯烃类环氧化等领域表现出的优良性能得到了广泛关注.目前,合成含不同杂原子的分子筛已成为分子筛材料开发的一个重要内容.分子筛的微孔孔道结构赋予了被引入其中作为催化中心的杂原子对反应物/产物分子独特的择形选择性;同时,分子筛骨架与杂原子之间往往存在化学键或空间限域作用,使得杂原子在高温高压等反应条件下依然保持高度的分散性,避免由于团聚导致活性降低.钴离子及含钴化合物在烷烃及芳烃类催化氧化反应中表现出很好的活性,能够利用分子氧实现对高碳烷烃及烷基苯的催化氧化.将钴离子及其化合物引入具有合适孔道结构的分子筛,可以提高催化反应的选择性.目前将对含钴分子筛的合成研究主要有后处理法及直接水热法.后处理法包括负载法及离子交换法,用于制备含有钴物种的硅铝分子筛;而直接水热法主要用于制备含有骨架钴的磷酸铝分子筛.目前为止,使用水热法合成含钴的分子筛材料的合成及其催化应用至今鲜有研究报导.这主要是由于传统的分子筛合成体系的高碱性环境会导致钴盐的沉淀,导致其无法被引入分子筛.我们通过优化合成条件,利用含氟体系直接水热法将钴引入Beta分子筛,得到含超微氧化亚钴团簇的Beta沸石分子筛.通过扫描电子显微镜、X射线粉末衍射、紫外-可见漫反射光谱、X射线光电子能谱、透射电子显微镜及H2程序升温还原等表征手段对合成样品的物理化学性质进行了研究,并与使用浸渍、离子交换得到的含钴Beta沸石及水热合成得到的含钴AlPO-5分子筛的相关性质进行了对比.合成得到的含钴分子筛材料中,钴物种以亚纳米尺度的氧化亚钴颗粒形式存在.我们使用分子氧作为氧源,考察了该含超微氧化亚钴的Beta沸石作为催化剂催化乙苯氧化反应的活性.与浸渍、离子交换制得钴硅分子筛及含有骨架钴的磷酸铝分子筛材料相比,含超微氧化亚钴的Beta分子筛表现出更高的催化活性及对苯乙酮/醛的选择性.     

Functionalization of polyethylene based on metallocene catalysis and its application to syntheses of new graft copolymers possessing polar polymer segments

The control of hydroxylated polyethylene (PE) structures was investigated in the copolymerization of ethylene with allyl alcohol or 10-undecen-1-ol with a specific metallocene, methylaluminoxane, and trialkyl aluminum catalyst system through changes in the copolymerization conditions. The incorporation of allyl alcohol into the PE backbones was controllable through changes in the trialkyl aluminum, leading to terminally hydroxylated PE or a copolymer possessing hydroxyalkyl side chains. The copolymerization of ethylene with 10-undecen-1-ol gave copolymers with hydroxyalkyl side chains of various contents with a variety of molecular weights through changes in the copolymerization conditions. The obtained copolymers were useful as macroinitiators that allowed polar polymer segments to grow on the PE backbones, leading to the creation of graft copolymers that possessed PE and polar polymer segments. In this way, polyethylene-g-poly(propylene glycol) (PE-g-PPG) and polyethylene-g-poly(ϵ-caprolactone) (PE-g-PCL) were synthesized. The ¹³C NMR analysis of PE-g-PPG suggested that all the hydroxyl groups were consumed for propylene oxide polymerization, and transmission electron microscopy demonstrated nanoorder phase separation and indistinct phase boundaries. ¹³C NMR and gel permeation chromatography analyses indicated the formation of PE-g-PCL, in which 36–80 mol % of the hydroxyl groups worked as initiators for ϵ-caprolactone polymerization. © 2003 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 3657–3666, 2003     

Polymerization of epoxidized vegetable oil derivatives: Ionic‐coordinative polymerization of methylepoxyoleate

Ring‐opening polymerization of epoxidized methyloleate (EMO) with various ionic‐coordinative initiators have been studied and compared with other internal epoxy monomers: benzyl 9,10‐epoxyoleoylether and cis‐4,5‐epoxyoctane. The structure and molecular weight of the resulting polymers have been studied by ¹H‐ and ¹³C‐NMR, MALDI‐TOF‐MS, and size exclusion chromatography analysis. Polymers with higher molecular weight than those obtained with conventional cationic catalyst are obtained. These materials have been found to consist of a complex mixture of cyclic and linear polymer chains with different chain ends that can be related to the catalyst nature and the occurrence of two main polymerization mechanisms, the cationic and the ionic‐coordinative. In the polymerization of EMO, transesterification by‐side reactions leading to ester linkages in the main chain have been identified. These undesired reactions have been suppressed by copolymerization with small amounts of tetrahydrofuran with no substantial decrease in the polymer yield and molecular weight. Finally, the polymerization of EMO has been tested in a larger scale to prepare a renewable resource‐based polyether as starting material to produce polyether polyols for polyurethane applications. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010     

Cobalt‐catalyzed alternating and nonalternating copolymerization of carbon monoxide with aziridine

Catalysts CH₃COCo(CO)₃PPh₃ ( 1 ) and HCo(CO)₃PPh₃ ( 2 ) catalyze the copolymerization of aziridine and carbon monoxide. Catalyst 2 can be conveniently generated in situ via reaction of Na⁺Co(CO)₄, N,N‐dimethylanilinium chloride, and PPh₃. The copolymerization alternates at high catalyst loadings to produce poly(β‐alanine). The end groups of the poly(β‐alanine) product are characterized by matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry and by comparison of the ¹H NMR spectra of the polymer and a stepwise synthesized model compound. At low catalyst loadings, the polymer product contains both the β‐alanine units and amine units because of nonalternating enchainment of the comonomers. The characterization of the amine units is again supported by comparison of the ¹H NMR spectra of the polymers and the stepwise synthesized model compounds. The molecular weights of the polymers are determined by gel permeation chromatography. The thermal stability of the polymers is probed by differential scanning calorimetry and thermogravimetric analysis. © 2002 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 41: 376–385, 2003     

Synthesis of poly(vinylene-arsine)s: alternating radical copolymerization of arsenic atomic biradical equivalent and phenylacetylene

Novel organoarsenic polymers, poly(vinylene-arsine)s, were synthesized by a free-radical alternating copolymerization of phenylacetylene with cyclooligoarsines as an atomic biradical equivalent. The polymerization between pentamethylpentacycloarsine (1a) or hexaphenylhexacycloarsine (1b) with phenylacetylene (2) in the presence of a catalytic amount of AIBN (in benzene; refluxing; for 12 h) gave the corresponding poly(vinylene-arsine)s. The obtained polymers were soluble in common organic solvents such as THF, chloroform, and benzene. From gel permeation chromatographic analysis (chloroform, PSt standards), the number-average molecular weights of the polymers from 1a and 1b were found to be 11500 and 3900, respectively. The structures of the polymers were supported by 1H and 13C NMR spectroscopies. The corresponding polymer was also obtained by irradiation of a benzene solution of 1a and 2 with xenon lamp at room temperature. After the polymer from 1a was stirred vigorously with 30% H2O2, the 1H NMR spectrum of the polymer showed the methyl proton that was assigned to As(III)-Me, suggesting the insensitivity of the trivalent state arsenic in the main chain to the oxidation. The structures and the molecular weights of the polymers were insensitive to the feed ratio of the monomers. This result indicates that the addition of the arsenic radical to phenylacetylene was a rate-determining step in the copolymerization.     

Studies on the Self-condensing Vinyl Polymerization of a Novel Maleimide Inimer

The self-condensing vinyl polymerization(SCVP) of a novel maleimide inimer(initiator-monomer) 1, N-(4-α-bromobutyryloxy phenyl) maleimide with the complex of CuBr/Bipy (2, 2‘-bipyridine) as the catalyst was studied. GPC was used to determine the molecular weight and the results show that the molecular weight increases exponentially with polymerization time during the first hour, and then the rate of increase molecular weight slows down. The molecular weight also increases with increasing dosage of the catalyst. The coincidence of the molecular weights determined by ^1H NMR and GPC proves that the polymer obtained from the SCVP of inimer 1 has a linear structure, whichis further verified by ^13C NMR spectrum. A hyperbranched polymer was obtained by the copolymerization of inimer 1 and styrene.     

Molecular weight distribution of metallocene polymerization with long chain branching using a binary catalyst system

In metallocene polymerization, termination by β-hydride elimination generates polymer chains containing unsaturated vinyl groups at their chain ends. Further polymerization of these macromonomers produces branched polymers. Material properties of the branched polymers not only depend on molecular weight and branching density, but also on chain structure. This work presents analytical expressions to predict the bivariate distribution of molecular weight and branching density for polymer chains having dendritic and comb structures. It is shown that when a single metallocene catalyst is used the formation of dendritic polymers is favored with only a very small fraction of highly branched chains assuming comb structure. The use of a binary catalyst system is therefore proposed to obtain high content of comb polymers. One catalyst generates macromonomers and the other yields in-situ branching. It is found that the comb polymers give much narrower molecular weight distributions than dendritic polymers with same branching densities.     

Heterogeneous grafting on polymers containing chlorine: Grafting of amide groups in water suspension and the reactivity of the new polymer towards epoxy resins

Heterogeneous grafting on polyvinylchloride suspended in water was carried out using N-butyl-3-mercaptopropionamide as nucleophile. Over 50% graft was obtained by using a small amount of solvent as a swelling agent and tricapryl methyl ammonium chloride as a phase transfer catalyst. Elemental analysis of the grafted polymer shows that the chlorine displaced from the polymers is replaced by the thio-amide group. The above conclusion is supported by NMR and IR analysis. The kinetics of the chlorine displacement from PVC by the thio amide group obeys the Shell progressive mechanism. The rate at which an individual spherical particle reacts depends on the diffusion through the reacted layer. The grafted polymer is soluble in tetrahydrofuran or nitrobenzene. The films obtained from the grafted material are brittle due to excessive internal hydrogen bonding. The electrostatic charge which is a characteristic surface phenomena in PVC is diminished in the grafted polymer which may be due to the existence of the amide group near the surface. The amide groups attached to the side chains on the polymer may participate in various reactions, e.g., with epoxy resins. IR analysis of the cured film indicates the disappearance of the oxiran band at 913 cm^?1 and an increase in the hydroxyl band around 3300 cm^?1. Thus, grafting of amide groups on PVC enables us to further modify PVC by epoxy resins.     

Branched polymer via free radical polymerization of chain transfer monomer: A theoretical and experimental investigation

A simple mathematic model for the free radical polymerization of chain transfer monomers containing both polymerizable vinyl groups and telogen groups was proposed. The molecular architecture of the obtained polymer can be prognosticated according to the developed model, which was validated experimentally by homopolymerization of 4‐vinyl benzyl thiol (VBT) and its copolymerization with styrene. The chain transfer constant (C_T) of telogen group in a chain transfer monomer is considered to play an important role to determine the architecture of obtained polymer according to the proposed model, either in homopolymerization or copolymerization. A highly branched polymer will be formed when the C_T value is around unity, while a linear polymer with a certain extent of side chains will be obtained when the C_T value is much bigger or smaller than unity. The C_T of VBT was determined to be around 15 by using the developed model and ¹H NMR monitored experiments. The obtained poly(VBT) and its copolymers were substantiated to be mainly consisted of linear main chain with side branching chains, which is in agreement with the anticipation from the developed model. The glass transition temperature, number average molecular weight, and its distribution of those obtained polymer were primarily investigated. This model is hopefully to be used as a strategy to select appropriate chain transfer monomers for preparing hyperbranched polymers. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1449–1459, 2008     

高分子量二氧化碳-环氧丙烷共聚物的合成条件研究

利用新型多配体负载戊二酸锌来催化二氧化碳和环氧丙烷合成高分子量聚碳酸(1,2-丙二醇).通过研究反应时间和反应压力对产率以及产物的结构和性能的影响来对反应条件进行了优化.结果表明在反应压力为5.2MPa,反应时间为40h时所得聚合物的数均分子量大于23×104,玻璃化转变温度达到38℃,拉伸强度达到31MPa.