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1.
以AlCl3和(CF3SO3)3Al为引发剂,CH2Cl2为溶剂,在20℃聚合了1,3 戊二烯(PD).对聚合物(PPD)的结构分析表明,(CF3SO3)3Al生成的聚合物具有较高的环化度.聚合物的环化过程是通过两种机理,分子内链转移机理和阳离子引发机理,后者可以通过加入DtBP得到抑制.AlCl3引发的聚合反应中环化过程以前一种机理为主,而(CF3SO3)3Al则以后一种机理为主.通过阳离子引发的环化反应主要发生在PPD1,2单元侧基双键上  相似文献   

2.
考察了复合催化剂AlCl_3/SbCl_3的不同配制方法和质子捕捉剂2,6-二异丁基-4-甲基吡啶(DTBMP)对α-蒎烯阳离子聚合反应的影响。结果表明,AlCl_3和SbCl_3加热熔融复合比简单复合的引发聚合活性更高;DTBMP对该复合催化剂的聚合反应速率及其产物分子量分布均无明显影响,证明该复合催化剂形成的活性种本质上与质子H活性种不同,是新型活性种。根据27AlNMR对该体系活性种分析结果,认为引发阳离子是[Sb(V)Cl_4],抗衡阴离子是[Al_2Cl_7]  相似文献   

3.
标题化合物(Me_2SiSiMe_2)[η ̄5-(3-Me_3SiC_5H_3)Fe(CO)_2]_2/(μ-CO)_2(A)分子中的Fe-Fe键被钠汞齐还原断裂,生成相应的双铁负离子,分别与MeCOCl、PhCOCl、PhCH_2Cl、ClCH_2COOC_2H_5和Ph_3SnCl进行亲核取代反应,生成在铁原子上引入相应取代基的产物(Me_2SiSiMe_2)[η ̄5-(3-Me_3SiC_5H_3)Fe(CO)_2R]_2(R:MeCO(1),PhCO(2),PhCH_2(3),CH_2COOC_2H_5(4),Ph_3Sn(5),I(6))。A在氯仿中与碘反应,得到Fe-Fe断裂的双铁碘化物,但在苯中与过量碘反应,则得到Fe-I-Fe桥联的离子型化合物(Me_2SiSiMe_2)[η ̄5-(3-Me_3SiC_5H_3)Fe(CO)_2]_2I·I(7)。化合物6的晶体和分子结构经X射线衍射测定,6属单斜晶系,P21/c空间群,a=1.7217(4)nm,b=0.7753(2)nm,C=1.3629(7)nm,β=103.80(3)°,V=1.767(2)nm3,Z=4,Dc=1.6299·cm-1,最终偏差因子R=0.054。  相似文献   

4.
本文研究了以甲苯为溶剂,AlCl3和BF3·OEt2为引发剂,1,3-戊二烯(PD)与苯乙烯(St)的阳离子共聚合反应,并用红外光谱测定聚合物的微观结构。由共聚单体PD和St加入顺序的不同可生成无规共聚物P(PD-co-St)和接枝共聚物P(PD-g-St)和P(St-g-PD)。无论是由AlCl3引发聚合反应,还是由BF3·OEt2引发聚合反应,St上的碳阳离子的活性都高于PD上碳阳离子的活性。由AlCl3首先引发PD进行聚合反应,结束后再引入St时,聚合体系不能引发St聚合反应;相反AlCl3首先引发St聚合后的体系能继续引发PD的聚合反应。BF3·OEt2无论先引发St或是PD,都能在聚合反应完成后接着引发另一单体而生成接枝共聚物P(PD-g-St)和P(St-g-PD)。二苯醚与烯丙基氯的加入,提高了碳阳离子的稳定性,增加了聚合物的分子量,但降低了碳阳离子的活性,使得聚合反应的产率降低,同时对St和PD碳阳离子的活性次序无明显影响  相似文献   

5.
研究表明,SOCl2/SnCl4引发体系的苯乙烯聚合反应很快,但所得聚合产物的分子量分布宽(Mw/Mn=4.37),且其GPC曲线呈多重峰;单独加入季铵盐(n-Bu4NCl)或二甲基亚砜(DMSO)可使聚合产物分子量分布明显变窄,并随浓度的增加而加强,但程度有限,不显示活性聚合特征;DMSO和n-Bu4NCl同时加入,表现出协同效应,不仅能保持较高的聚合反应活性,而且产物分子量分布很窄(Mw/Mn=1.27),分子量随单体转化率增加而增加,且线性关系良好,聚合物链数只与引发剂初始浓度相关,显示活性聚合特征。  相似文献   

6.
标题化合物(Me2SiSiMe2)〔η^5-(3-Me3SiC5H3)Fe(CO)2〕2/(μ-CO)2(A)分子中的Fe-Fe键被钠汞齐还原断裂,生成相应的双铁负离子,分别与MeCOCl、PhCOCl、PhCH2Cl、ClCH2COOC2H5和Ph3SnCl进行亲核取代反应,生成在铁原子上引入相应取代基的产物(Me2SiSiMe2)〔η^5-(3-Me3SiC5H3)Fe(CO)2R〕2(R:M  相似文献   

7.
1,2-二(三甲硅基环戊二烯基)四甲基二硅烷与Fe(CO)_5在二甲苯中于105~110℃反应除分离到少量标题化合物(Me_2SiSiMe_2)[η-(3-Me_3SiC_5H_3Fe(CO)]_2(μ-CO)_2(5)外,主要是生成了脱Me_3Si基的产物(Me_2SiSiMe_2)[η-C_5H_4Fe(CO)]_2(μ-CO)_2(1)及1的热重排异构体[Me_2SiC5H4-Fe(CO)_2]_2(2).将5的二甲苯溶液加热回流18h,则转化为其异构体[Me_2Si(Me_3SiC_5H_3)Fe(CO)_2]_2(6).脱硅基发生在由相应反应物制备5的过程中。且脱硅基是与反应物中(Me_2SiSiMe_2)桥的存在有关.5的晶体结构经X射线衍射测定属单斜晶系,P2_1/m空间群,晶体学数据:a=0.6780(1)nm,b=2.2303(9)nm,c=0.9988(1)nn,;β=98.96(1)°,V=1.4960nm~3.Z=2,D_c=1.36g/cm~3.  相似文献   

8.
CH3COSbCl6催化四氢呋喃聚合的研究   总被引:4,自引:0,他引:4  
CH_3COSbCl_6催化四氢呋喃聚合的研究栗方星,王红军,马克勤(南开大学化学系,天津,300071)关键词聚四氢呋喃,乙酰基六氯锑酸盐,表观聚合反应速率常数,五氯化锑THF聚合为平衡聚合反应应[1,2],文献报道[3,4]Et3OBF4、Et3O...  相似文献   

9.
考察了新型催化剂Cp*Ti(CH2SiMe3)3/B(C6F5)3催化苯乙烯间规聚合的性能.结果表明,Cp*Ti(CH2SiMe3)3与B(C6F5)3等摩尔混合可形成高活性的催化剂,催化活性高达(0.7~1.37)×107g/(mol2·h),聚苯乙烯的间规度为95%以上.B(C6F5)3/Ti摩尔比不等于1时,其催化活性和间规立构选择性都明显降低.Al(i-Bu)3的加入不仅显著提高催化活性和间规立构选择性,而且还提高了间规聚苯乙烯的相对分子量.最佳聚合温度为343K.在c(St)=0.44~6.56mol/L范围内,苯乙烯聚合速率对苯乙烯单体呈一级反应,苯乙烯转化率和间规聚苯乙烯的相对分子量随反应时间的增加而提高.  相似文献   

10.
Ce2O—TiO2/SiO2的制备及除氟性能研究   总被引:5,自引:0,他引:5  
以SiO2为基质,CeO2TiO2为包覆物质,采用溶胶凝胶法制备CeO2TiO2/SiO2表面复合物,并对所制复合物进行除氟测试。用扫描电镜(SEM)观察表面形貌,讨论实验环境、试剂用量等因素对CeO2TiO2/SiO2制备及除氟性能的影响,结果表明:nTi(OC4H9)4/nCeCl3·7H2O=1、nCH3COOH/nTi(OC4H9)4=45、nC3H8O3/nTi(O4H9)4=03、RH=95%,热处理温度110℃时,所制CeO2TiO2/SiO2对F-的吸附容量(q)为214mg/g,去除率(E)为856%。  相似文献   

11.
邓建国  彭宇行 《中国化学》1998,16(5):452-457
Cationic polymerization of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride/aluminium chloride (TMSCl/AlCl3) was carried out in toluene at 30℃.The polymer yield was increased by the addition of TMSC1.However,introduction of TMSC1 gave rise to a drop of the polymer molecular weight.Kinetic results demonstrated that the polymerization initiated by TMSCl/AlCl3 was 2.8 times faster than that induced by AlCl3 alone.Various ethers and ketones were used to mediate the initiating system TMSCl/AlCl3.The polymer yield and molecular weight of the polymer were decreased in the presence of ether.Ketones and ethers had different effects on the polymerization,and the polymer yield and molecular weight were lower than those initiated by AlCl3 alone or TMSCl/AlCl3 Structural evidence revealed that the polymerization was indeed initiated by AlCl3 and HCl rcsulting from hydrolysis of TMSC1 by adventitious water.  相似文献   

12.
研究了三甲基硅化合物 ,主要是三甲基硅酯和三甲基硅氯化物 (TMSCI)与路易斯酸所形成的复合引发体系引发聚合 ,1,3 戊二烯 (PD)的聚合反应行为 ,考察了引发体系引发PD聚合所得聚合物的产率 ,分子量及分子量分布 ,聚合反应速率和聚合反应机理等 ;研究了多种给电体———醚、酮对聚合反应的影响  相似文献   

13.
Cationic polymerizations of 1,3-pentadiene (PD) initiated by trimethylsilyl chloride (TMSCl) incombination with TiCl_4 were carried out in n-hexane at 30℃. The yield of polymer was greatly increased bythe addition of TMSCl, indicating that the TMSCl/TiCl_4 combination is an efficient initiating system for PDcationic polymerization. However, the introduction of TMSCl gave rise to a drop in the molecular weight ofthe polymer. Kinetic results demonstrated that the polymerization initiated by TMSCl/TiCl_4 is 4.5 times fasterthan that induced by TiCl_4 alone. Various ethers were used to mediate the TMSCl/TiCl_4 initiating system.Adding diphenyl ether could increase both the yield and molecular weight of the polymer. Structural evidenceillustrates that the polymerization is indeed initiated by TiCl_4 in combination with HCl resulting fromhydrolysis by adventitious water.  相似文献   

14.
Various ethers were used to mediate the polymerizations of 1,3-pentadiene (PD) initiated by AlCl3 and by allyl chloride (AllyCl)/AlCl3. The introduction of the ethers exert considerable effects on polymer yield and molecular weight due to its interaction with the propagating carbocation. The carbocation reactivity is reduced by this interaction which is subject to the ether's nucleophilicity determined by the steric hindrance of groups adjacent to oxygen. The reduction of carbocation reactivity gives rise to a decrease of polymer yield owing to inhibition of propagation but results in an augmentation of molecular weight due to suppression of various side reactions such as terminations. By using suitably nucleophilic ethers such as diphenyl ether, the polymerization can be mediated to give an high molecular weight polymer in high yield.  相似文献   

15.
α-蒎烯、β-蒎烯、苧烯阳离子聚合的研究   总被引:1,自引:0,他引:1  
比较了萜烯单体α 蒎烯、β 蒎烯、烯的阳离子聚合性能,还考察了这三种单体的活性聚合可能性.在Lewis酸AlCl3作用下,聚合速率大小顺序为:β 蒎烯>烯>α 蒎烯.α 蒎烯、烯的聚合产物分子量较低;β 蒎烯的聚合产物分子量较高.AlCl3与SbCl3复合后,α 蒎烯、烯的聚合速率增加,β 蒎烯的聚合速率反而下降.α 蒎烯的聚合速率增加幅度大于烯,使得前者聚合速率高于后者.与使用AlCl3相比,添加SbCl3后产物的分子量变化是:α 蒎烯变大,烯不变,β 蒎烯则变小.添加SbCl3对β 蒎烯、烯的聚合物结构无影响,而α 蒎烯聚合产物的结构则发生显著变化.活性较高的β 蒎烯在适当的引发体系,如苯乙烯 HCl加成物/TiCl3(OiPr)作用下,可以实现活性聚合.α 蒎烯、烯则由于本身单体活性太小,难以实现活性聚合.  相似文献   

16.
邓建国  彭宇行 《化学学报》1998,56(10):1032-1036
研究了以三氟甲基磺酸三甲基硅酯[(CH~3)~3SiOSO~2CH~3,TMSOFf]为主引发剂,TiCl~4为共引发剂的复合引发体系对1,3-戊二烯(PD)的聚合行为。TMSOTf/TiCl~4复合体系引发PD不但比单独的TiCl~4引发具有更高的引发活性,而且提高了聚合物分子量,能把聚合反应速率提高8.8倍,把聚合物的收率从TiCl~4引发的62.5%提高到95%以上。对该复合体系聚合PD的动力学,反应机理所作的研究表明:TMSOTf和TMSOTf/TiCl~4都是通过它们与体系中残存水通过水解生成的质子酸引发进行的,聚合反应属一级反应。在该体系中加入酮类后,产率和分子量均降低,但均随着酮类的位阻的增加而增大。  相似文献   

17.
合成了Cp TiCl2 N[Si(CH3) 3]2 甲基铝氧烷 (MAO)催化体系 ,以该体系进行丙烯聚合得到无规聚丙烯 ,具有高的分子量及良好的弹性 ,玻璃化温度为 - 8 8℃ .产物经DSC、1 3C NMR、DMA等方法表征 .结果表明 ,催化活性随着丙烯压力的增加 ,有明显的增大 .催化活性在 4 0℃下有最高的催化活性 ,而产物分子量随着温度的下降有明显增大 ,在 0℃~ 5 0℃范围内分子量MW =(2 0~ 6 0 )× 10 4 .  相似文献   

18.
The structure of N,N-dimethylethylenediammonium pentachloroantimonate(III), [(CH3)2NH(CH2)2NH3][SbCl5], NNDP, was investigated at 100 and 15 K at ambient pressure, as well as at pressures up to 4.00 GPa at room temperature in the diamond-anvil cell. The stable structure at low temperatures and low pressures consists of isolated [SbCl5]2- anions and [(CH3)2NH(CH2)2NH3]2+ cations. The inorganic anions have a distorted square pyramidal geometry. They are arranged in linear chains parallel to the c axis. In contrast to the low-temperature studies, where no phase transition was detected, pressure induces a P2(1)/c --> P2(1)/n phase transition between 0.55 and 1.00 GPa, accompanied by a doubling of the a unit-cell parameter. This solid-solid transition results from changes in the electron configuration of the Sb(III) atom and formation of the Sb-Cl bridging bonds between inorganic polyhedra to form, at approximately 1.0 GPa, isolated [Sb2Cl10]4- units consisting of [SbCl6]3- octahedra and [SbCl5]2- square pyramids connected by a common corner. The intermolecular distances continuously decrease with further increase in pressure, and at approximately 3.1 GPa, zigzag [{SbCl5}n]2n- chains containing corner-sharing [SbCl6]3- octahedra are formed. The unit-cell volume of NNDP decreases by 18.15% between room pressure and 4.00 GPa. The linear distortions of the [SbCl5]2- and [SbCl6]3- polyhedra decrease with increasing pressure and decreasing temperature and indicate a reduction in the stereochemical activity of the lone electron pair on the Sb(III) atom.  相似文献   

19.
Various ethers were used to mediate the polymerization of 1,3-pentadiene (PD) initiated by AlCl3 and by allyl chloride (AllyCl)/AlCl3. The introduction of the ethers exert considerable effects on polymer yield and molecular weight due to its interaction with the propagating carbocation. The carbocation reactivity is reduced by this interaction which is subject to the ether's nucleophilicity determined by the steric hindrance of groups adjacent to oxygen. The reduction of carbocation reactivity gives rise to a decrease of polymer yield owing to inhibition of propagation but results in an augmentation of molecular weight due to suppression of various side reactions such as terminations. By using suitably nucleophilic ethers such as diphenyl ether, the polymerization can be mediated to give an high molecular weight polymer in high yield.  相似文献   

20.
通过氯化镧与Schiff碱钠盐(NaSalen)的交换反应制备了4种镧的Schiff碱配合物La(HSalen1-4)3,对其中以3,5-二叔丁基水杨醛缩苯胺为配体的配合物La(HSalen2)3进行了X-射线单晶衍射分析,测定其单晶结构为五角双锥构型,七配位的镧金属中心与氮和氧原子相连.将所得的La(HSalen)3...  相似文献   

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