四氢呋喃开环聚合的研究

本文探讨了以环氧氯丙烷(ECH)为促进剂,用发烟硫酸—高氯酸、乙酸酐—高氯酸为催化剂的四氢呋喃开环聚合。探讨了反应温度和ECH、高氯酸用量对开环聚合的分子量及产率的影响。采用了KOH回流法对原料进行处理,效果显著。     

Fe-Al-〆,〆′-联吡啶催化PA与PO、PA与ECH开环共聚

用 Fe(acac) 3- Al(i- Bu) 3- α,α′-联吡啶 (acac=乙酰丙酮 )催化邻苯二甲酸酐 (PA)与环氧丙烷 (PO)、邻苯二甲酸酐与环氧氯丙烷 (ECH)开环交替共聚 .研究了 Fe/Al、Fe/α,α′-联吡啶摩尔比对聚合的影响 ;用核磁共振技术研究了共聚物的交替度 ,测得共聚物中邻苯二甲酸酐含量达 46 %以上 .共聚反应动力学研究表明 ,共聚反应速度与单体浓度及催化剂浓度均呈一级关系 ;PA- PO、PA- ECH的表观活化能分别为 10 9.3和 99.7k J/mol     

Fe-Al-α,α′-联吡啶催化PA与PO、 PA与ECH开环共聚

用Fe(acac)3-Al(I-Bu)3-α,α′-联吡啶(acac=乙酰丙酮)催化邻苯二甲酸酐(PA)与环氧丙烷(PO)、邻苯二甲酸酐与环氧氯丙烷(ECH)开环交替共聚 . 研究了Fe/Al、 Fe/α,α′-联吡啶摩尔比对聚合的影响; 用核磁共振技术研究了共聚物的交替度, 测得共聚物中邻苯二甲酸酐含量达46%以上. 共聚反应动力学研究表明, 共聚反应速度与单体浓度及催化剂浓度均呈一级关系; PA-PO、 PA-ECH的表观活化能分别为109.3和99.7 kJ/mol.     

应用Juliá-Colonna不对称环氧化反应合成(-)-(2Z)-1-(4-腈基苯基)-3-(3,4-亚甲二氧基苯基)-2,3-环氧丙-1-酮

聚合氨基酸催化的α,β-不饱和酮的环氧化反应是由Juliá和Colonna[1]发现的,最初反应是在三相反应体系(聚合氨基酸、有机溶剂和H2O2-H2O-NaOH)中进行的,Adger等[2]对此条件进行了改进.以树脂固定的聚合氨基酸代替聚合氨基酸为手性催化剂;同时分别以Urea-H2O2和DBU代替H2O2和NaOH,使得反应可以在两相(催化剂和有机溶剂)体系进行.这些改进简化了操作,提高了催化剂的回收率,还扩大了反应的应用范围.     

用稀土催化剂合成顺-1,4-聚-2,3-二甲基丁二烯

<正> 我们的工作及文献证明,稀土催化剂可使丁二烯、异戊二烯及1,3-戊二烯聚合生成顺-1,4聚合物,而对2,4-己二烯则可得到反-1,4-苏式-双全同立构聚合物(trans-1,4-threo-diisotactic polyhexadiene),为了进一步弄清稀土催化剂对不同双烯烃的催化聚合活性以及所得聚合物的结构与单体性质的关系,我们研究了2,3-二甲基丁二烯在三元催化剂Nd(naph)_3-AlEt_2Cl-Al(-Bu)_3作用下的聚合及所得聚合物的结构。     

三氟化硼引发四氢呋喃聚合的研究——Ⅳ.1,4-丁二醇的影响

前报中已证明用三氟化硼-环氧氯丙烷(ECH)引发四氢呋喃(THF)聚合具有较高的引发效率,并对在Ac_2O、水和无水存在下的聚合反应进行了研究。本文报道1,4-丁二醇(BG)对BF_3引发THF聚合反应的影响。通常认为在BG存在下,BF_3是不能引发THF聚合的,但本工作证明BG是有效的分子量调节剂,制备分子量在     

三氟化硼引发四氢呋喃聚合的研究——Ⅱ. 水的影响

<正> 分子量在3000以下的四氢呋喃聚合产物-聚丁二醇(PTMG)是重要的工业原料。前报中我们已证明用BF_3-环氧氯丙烷(ECH)引发四氢呋喃(THF)聚合时引发效率较高,在这一基础上有希望通过在聚合体系中加水以达到控制产物分子量的目的。 文献上对水在BF_3-ECH引发THF聚合反应中作用的研究不多,Kyzaeb等人     

铁、钴催化剂乙烯聚合原位紫外-可见光谱研究

利用乙烯常压聚合原位紫外 可见 (UV Vis)光谱技术 ,对 3个铁、钴络合物作为催化剂前体的催化剂体系进行了研究 .3个铁、钴络合物分别为 2 ,6 双 [1 (2 ,6 二甲基苯基亚胺 )乙基 ]吡啶二氯化铁 (a)、2 ,6 双 [1 (2 ,4,6 三甲基苯基亚胺 )乙基 ]吡啶二氯化铁 (b)和 2 ,6 双 [1 (2 ,6 二异丙基苯基亚胺 )乙基 ]吡啶二氯化钴(c) .实验结果表明 ,MAO对络合物催化剂前体的活化作用是一个快速过程 ;在聚合条件下分别观察到 5 6 0、6 30和 5 80nm的活性峰 ,考察了它们在聚合过程中的生长和在加入无水乙醇逐步使催化剂中毒时活性峰的消失规律 .对催化剂活性物种的结构和聚合机理进行了探讨     

双-(β-酮萘胺)镍(Ⅱ)/MAO催化剂体系催化苯乙烯聚合

 采用双-(β-酮萘胺)镍(Ⅱ)为主催化剂,以甲基铝氧烷(MAO)为助催化剂,在甲苯溶剂中进行了苯乙烯聚合实验,并考察了聚合温度、Al/Ni摩尔比、单体浓度和聚合时间等因素对聚合反应的影响. 结果表明,双-(β-酮萘胺)镍(Ⅱ)/MAO催化剂显示出很高的催化活性,可催化苯乙烯聚合得到中等分子量和分子量分布较窄(Mw/Mn＜1.6)的聚苯乙烯. 采用核磁共振氢谱、核磁共振碳谱、傅里叶变换红外光谱、差示扫描量热法和广角X射线衍射技术对聚合产物进行了表征. 结果表明,所得聚合物为无规聚苯乙烯.     

用Ziegler-Natta型催化剂聚合α-烯类的动力学

一、引言在高分子合成的领域内,如何获得规整结构的聚合物是早为人们注意的问题。目前不仅可用离子型催化剂,而且也用自由基引发剂来制备规整的结晶高聚物。但其中以Ziegle-Natta型催化剂显得更为突出,这方面已进行了大量的研究工作,新的催化系统(均相和异相)在不断出现;不过其聚合机理尚在争论中,仍为今后科学研究的主要对象(目前大多数作者认为是配位阴离子聚合)。动力学研究不仅对聚合机理的探索,而且也为工业生产提供有益数据。用ziegler-Natta型催化剂聚合α-烯类的动力学与     

环氧化物稀土络合催化开环聚合动力学研究

用膨胀计方法研究环氧丙烷、环氧氯丙烷在稀土络合催化剂 Nd(P_(204))_3-Al(i-Bu)_3-H_2O作用下的聚合反应动力学,表明聚合反应速度对催化剂浓度及单体浓度均呈一级关系。环氧丙烷、环氧氯丙烷开环聚合反应活化能分别为61.3kJ/mol和48.9kJ/mol。在同样的聚合反应条件下,环氧氯丙烷聚合反应速度大于环氧丙烷聚合反应速度。 研究还发现,催化剂组成摩尔比Al/Nd及H_2O/Al对聚合反应速度均有一定影响;各种稀土元素络合催化剂催化活性顺序为:Nd>La>Dy>Yb>Eu;稀土络合物中配体对活性的影响为:acac>P_(204)>P_(507)>naph;烷基铝的影响为:Al(i-Bu)_3>AlEt_3。     

Polymerization of alkylene oxides with aluminum alkyl–strong phosphoric acid–lewis base catalyst

Polymerization of epichlorohydrin (ECH) and copolymerization of propylene oxide–allyl glycidyl ether were studied by using a catalyst consisting of aluminum alkyl–strong phosphoric acid–Lewis base. This system showed high polymerization activity for alkylene oxides, and it was elucidated by x-ray diffraction analysis that the resultant ECH polymer was completely amorphous. The polymerization was presumed to be of the coordinated anionic type. The physical properties of the vulcanized polymers were studied.     

THE POLYMERIZATION OF EPICHLOROHYDRIN WITH Nd(i-oPr)_3-Al(i-Bu)_3 SYSTEM

Epichlorohydrin (ECH) was polymerized with a rare earth catalytic system: Nd (i-OPr)_3-Al (i-Bu)_3. The effects of Al/Nd molar ratio, solvents, the polymerization time and temperature,the aging time and temperature of the catalyst preparation were studied. The results showed thatat a low Al/Nd molar ratio (4) of the Nd(i-OPr)_3-Al(i-Bu)_3 system ECH polymerized at a lowtemperature (248K) with a high conversion. The average molecular weight ofpolyepichlorohydrin (PECH) ranged from 1×10~5 to 3×10~5.     

Synthesis of Novel Polyether Polyol by Using Double Metal Cyanide

Hydroxyl-terminated novel polyether polyols were synthesized by polymerization of epichlorohydrin (ECH) catalyzed by double metal cyanide (DMC) catalyst. The effects of reaction temperature and catalyst concentration on the polymerization of Polyether Polyol were studied. The molecular structure and the damping properties were measured by IR spectra, ¹H-NMR spectra and the dynamic mechanical analysis.     

杂多酸引发四氢呋喃开环聚合反应Ⅵ.以环氧氯丙烷为促进剂

在以低浓度杂多酸(ＨＰＡ)催化四氢呋喃(ＴＨＦ)聚合反应中,我们曾采用环氧乙烷(ＥＯ)和环氧丙烷(ＰＯ)为促进剂,发现它们都具有很好的促进效果[1,2],并且活性相近.在以三氟化硼(ＢＦ3)为催化剂的四氢呋喃正离子开环聚合反应中,促进剂的活性次序为:ＥＣＨ(环氧氯丙烷)>ＰＯＥＯ[3].在ＨＰＡ催化ＴＨＦ聚合反应中,ＥＣＨ是否仍具有高的促进活性是本文研究的目的.1　原料及聚合操作ＴＨＦ的纯化见文献[4],ＥＣＨ的纯化见文献[5],十二磷钨杂多酸(ＰＷ12)的处理见文献[1],三氟醋酸酐的合成方法和聚合反应的操作均见前文[2].2　分析测试核磁共振…     

Thermal and real-time FTIR spectroscopic analysis of the photopolymerization of diepoxide-vinyl ether mixtures

Both epoxides and vinyl ethers can be polymerized cationically albeit through different intermediates. However, in the case of epoxide-vinyl ether mixtures the exact mechanism of cationically initiated polymerization is unclear. Thus, although vinyl ethers can be used as reactive diluents for epoxides it is uncertain how they would affect their reactivity. Cationic photocuring of diepoxides has many industrial applications. Better understanding of the photopolymerization of epoxy-vinyl ether mixtures can lead to new applications of cationically photocured systems. In this work, photo-DSC and real-time Fourier Transform Infrared Spectroscopy (RT-FTIR) were used to study cationic photopolymerization of diepoxides and vinyl ethers. In the case of mixtures of aromatic epoxides with tri(ethylene glycol) divinyl ether, TEGDVE, photo-DSC measurements revealed a greatly reduced reactivity in comparison to the homopolymerizations and suggested the lack of copolymerization between aromatic epoxides and TEGDVE. On the other hand, for mixtures of 3,4-epoxycyclohexylmethyl-3',4'-epoxycyclohexane carboxylate, ECH, with TEGDVE the results indicated high reactivity of the blends. The polymerization mechanism might include copolymerization. To examine this mechanism, mixtures of the ECH with a tri(ethylene glycol) mono-vinyl ether, TEGMVE, were studied by both photo-DSC and RT-FTIR. Principal component analysis (PCA) proved to be an efficient tool in analyzing a large matrix of the spectral data from the polymerization system. PCA was able to provide insight into the reasons for the differences among replicated experiments with the same composition ratio and supported the hypothesis of copolymerization in the ECH/TEGMVE system. Thus, blends of cycloaliphatic epoxides and vinyl ethers seem to have a great potential for applications in high-productivity industrial photopolymerization processes. This revised version was published online in July 2006 with corrections to the Cover Date.     

The versatile,functional polyether,polyepichlorohydrin: History,synthesis, and applications

Polyepichlorohydrin (PECH) is a functional polyether first synthesized in the 1950's by the catalytic ring opening polymerization of epichlorohydrin (ECH), its inexpensive epoxide pre-cursor. PECH elastomers are used in diverse commercial applications due to their unique combination of properties including low temperature flexibility and heat and oil resistance. PECH holds an interesting place in polymer history as its synthesis led to the discovery of highly effective aluminum-based catalysts for epoxide polymerizations and a new class of high molecular weight polyether elastomers by an exceptional polymer chemist, Edwin J. Vandenberg. ECH is an ideal feedstock for polymer materials as it is functional, inexpensive, and produced through environmentally friendly means. However, due to the alkyl chloride pendant, polymerizations involving ECH are difficult and limited synthetic advancement has occurred until very recently. This focused review will discuss modern polymerization methods involving ECH while giving a historical perspective on the evolution of these techniques. We will also review applications of ECH-based polymers and discuss the future development of these materials. We hope to convince the reader to explore ECH-based materials in their own work.     

乙酰丙酮钇催化环氧氯丙烷的均聚合与共聚合

用过渡金属络合催化剂聚合环氧氯丙烷能获高分子量的聚合物。稀土络合催化剂对环氧乙烷,环氧丙烷及环硫丙烷的开环聚合具有明显效果。本文选用Y(acac)_3-H_2O-Al(i-Bu)_3催化剂,考察环氧氯丙烷的均聚合及其与环氧乙烷,环氧丙烷的共聚合,并用核     

Synthesis of novel tetrahydrofuran‐epichlorohydrin [poly(THF‐b‐ECH)] macromonomeric peroxy initiators by cationic copolymerization and the quantum chemically investigation of initiation system effects

Cationic polymerization of tetrahydrofuran (THF) and epichlorohydrin (ECH) was performed with peroxy initiators synthesized from bis (4,4′‐bromomethyl benzoyl peroxide (BBP) or bromomethyl benzoyl t‐butyl peroxy ester (t‐BuBP) and AgSbF₆ or ZnCl₂ system at 0 °C to obtain the poly(THF‐b‐ECH) macromonomeric peroxy initiators. Kinetic studies were accomplished for poly(THF‐b‐ECH) initiators. Poly(THF‐b‐ECH‐b‐MMA) and poly(THF‐b‐ECH‐b‐S) block copolymers were synthesized by bulk polymerization of methyl methacrylate (MMA) and styrene (S) with poly(THF‐b‐ECH) initiators. The quantum chemical calculations for the block copolymers, the initiating systems of the cationic polymerization of THF and ECH were achieved using HYPERCHEM 7.5 program. The optimized geometries of the polymers were investigated with the quantum chemical calculations. Poly(THF‐b‐ECH) initiators having peroxygen groups were used for graft copolymerization of polybutadien (PBd) to obtain poly(THF‐b‐ECH‐g‐PBd) crosslinked graft copolymers. The graft copolymers were investigated by sol‐gel analysis. Swelling ratio values of the graft copolymers in CHCl₃ were calculated. The characterizations of the polymers were achieved by FTIR, ¹H NMR, GPC, SEM, TEM, and DSC techniques. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 2896–2909, 2010