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1.
根据文献查得的Q、e值,计算了三烯两基异氰酸尿酯-二乙烯苯-醋酸乙烯三元共聚体系的竞聚率,预测了它们进行共聚的可能性.以甲苯和汽油为致孔剂,采用悬浮聚合的方法合成了此三元大孔共聚物,并研究了致孔剂用量、交联度等对共聚物孔性能的影响。实验发现,此共聚体系在适当条件下,可以制得很高比表面积的大孔共聚体,比表面积可高达1214m2/g。对合成的共聚物又进行了醇解反应,得到了含羟基的共聚体。  相似文献   

2.
不同联苯含量的PEEKK-PEBEKK共聚物的DSC结果表明,随着联苯含量的增加,共聚物的玻璃化转变温度几逐渐升高;共聚物的熔点Tm明显地依赖于联苯含量,当联苯含量nB=0.35时,Tm值最4小。热处理可以显著地改善共聚物的结晶性,并出现熔融重结晶双峰。  相似文献   

3.
张宏放  那辉 《应用化学》1996,13(2):57-60
不同联苯含量的PEEKK-PEBEKK共聚物的DSC结果表明,随着联苯含量的增加,共聚物的玻璃化转变温度Tg逐渐升高;共聚物的熔点Tm明显地依赖于联苯含量,当联苯含量nB=0.35时,Tm值最小。热处理可以显著地改革共聚物的结晶性,并出现熔融重结晶双峰。  相似文献   

4.
将乙肝表面抗体与N-羟基琥珀酰亚胺丙烯酸酯反应,生成丙烯酰基抗体.丙烯酰基抗体与甲基丙烯酸、丙烯酰胺共聚,生成pH敏感的三元共聚物.三元共聚物溶解.沉淀的临界pH值为3.8.三元共聚物上的抗体能与表面抗原、酶标抗体形成夹心复合物.利用三元共聚物可逆的溶解.沉淀特性,能实现在均相条件下,进行免疫反应,在异相条件下,进行免疫复合物的分离.  相似文献   

5.
两亲嵌段共聚物溶液内胶束形成的温度效应   总被引:2,自引:0,他引:2  
合成了一系列具有两亲嵌段结构的聚(乙二醇)(PEO)一聚(丙二醇)(PPO)共聚物.利用荧光探针及示差量热法测定了共聚物水溶液的临界胶束形成温度(CMT)值.发现二嵌段共聚物(PEO-PPO)和三嵌段共聚物(PEO-PPO-PEO)有着类似的变化规律,即随共聚物分子中疏水链(PPO)长度的增大,其CMT值降低.但三嵌段共聚(PPO-PEO-PPO)则因疏水链段处于共聚物分子的两端,因而在溶液中有可能形成立体网状交联结构.此外,利用探针分子在不同极性溶剂中荧光峰值波长发生位移的现象可以对形成胶束内核的组织程度、极性大小进行估测.  相似文献   

6.
根据文献查得的Q,e值,计算了三烯丙基异氰酸尿酯-二乙烯苯-醋酸乙烯三元共聚体系的竞聚率,预测了它们进行共聚的可能性。以甲苯和汽油为致孔剂,采用悬浮聚合的方法合成了此三元大孔共聚物,并研究了致孔剂用量,关联度等对共聚物孔性能的影响。实验发现,此共聚体系在适当条件下,可以制得很高比表面积的大孔共聚体,比表面积可高达1214m^2/g。对合成的共聚物又进行了醇解反应,得到了含羟基的共聚体。  相似文献   

7.
甲基丙烯酸甲酯-丙烯酸丁酯共聚物微观结构研究   总被引:3,自引:0,他引:3  
用13C NMR研究了由基团转移共聚得到的甲基丙烯酸甲酯 丙烯酸丁酯共聚物的微观结构,共聚物中单体链节的三元组含量从季碳和羰碳的共振信号测得,实验测得的三元组分数与通过竞聚率和单体组成比按末端基效应模式的计算值相符.丙烯酸丁酯由于具有大得多的竞聚率值而呈现较强的均聚倾向.  相似文献   

8.
根据Flory热力学统计理论和比容-熔融热作国法,由DSC结果得到了不同联苯含量的聚醚醚酮酮-含联苯聚醚醚酮酮(PEEKK-PEBEKK)共聚物的熔融热,两种方法获得的结果吻合。在此基础上给出了PEEKK-PEBEKK共聚物不同联苯含量的熔点计算表达式。结果还表明,随着联苯含量nB,的变化,明显改变;当nB=0.35时,PEEKKPEBEKK共聚物的值最小。  相似文献   

9.
本文采用氧化还原引发体系合成了丙烯腈与马来酸酐共聚物,各首次将此共聚物制成了醇,水分离用的渗透蒸发膜,研究了不同马来酸酐含量的共聚物膜碱中的水解规律,考察了共聚物,料液温度,料液浓度等条件对膜的醇,水分离性能的影响关系以及水解前,后膜性能的变化结果表明,当共聚物中马来酸酐含量大于0.069(摩尔分数)时,水解前,后膜性能有很大的变化,分离因子,渗透通量和膜强度都普遍提高。另外,还发现该共聚物膜与其  相似文献   

10.
将等离子体接枝技术用于聚丙烯接枝苯乙烯共聚物的合成.FT IR、SEM及XPS证明所得产物为接枝共聚物.研究了不同等离子体处理体系压强、处理功率,反应瓶不同直径、体积,不同接枝聚合反应时间、温度对接枝率的影响.利用接枝共聚物制备了硫酸钠型离子交换膜,并对其电性能进行了初步探讨.  相似文献   

11.
<正> 在铑催化剂的作用下,甲醇与一氧化碳经羰基化反应为乙酸和乙酸甲酯,是60年代发展起来的新工艺,但以往多是采用均相小分子铑催化剂,除我们的工作以外,迄今尚少见报道有采用以共聚物为配体的高分子铑催化剂的成功先例。  相似文献   

12.
The carbonylation of methanol to acetic acid is a hugely important catalytic process, and there are considerable cost and environmental advantages if a process could be designed that was tolerant of hydrogen impurities in the CO feed gas, while eliminating by-products such as propionic acid and acetaldehyde altogether. This paper reports on an investigation into the application of rhodium complexes of several C(4) bridged diphosphines, namely BINAP, 1,4-bis(diphenylphosphino)butane (dppb), bis(diphenylphosphino)xylene (dppx) and 1,4-bis(dicyclohexylphosphino)butane (dcpb) as catalysts for hydrogen tolerant methanol carbonylation. An investigation into the structure, reactivity and stability of pre-catalysts and catalyst resting states of these complexes has also been carried out in order to understand the observations in catalysis. Rh(I) carbonyl halide complexes of each of the ligands have been prepared from both [Rh(2)(CO)(4)Cl(2)] and dimeric mu-Cl-[Rh(L)Cl](2) complexes. These Rh(I) carbonyl complexes are either dimeric with bridging phosphine ligands (dppb, dcpb, dppx) or monomeric chelate complexes. The reaction of the complexes with methyl iodide at 140 degrees C has been studied, which has revealed clear differences in the stability of the corresponding Rh(III) complexes. Surprisingly, the dimeric Rh(I) carbonyls react cleanly with MeI with rearrangement of the diphosphine to a chelate co-ordination mode to give stable Rh(III) acetyl complexes. The Rh acetyls for L=dppb and dppx have been fully characterised by X-ray crystallography. During the catalytic studies, the more rigid dppx and BINAP ligands were found to be nearly 5 times more hydrogen tolerant than [Rh(CO)(2)I(2)](-), as revealed by by-product analysis. The origin of this hydrogen tolerance is explained based on the differing reactivities of the Rh acetyls with hydrogen gas, and by considering the structure of the complexes.  相似文献   

13.
针对共聚物配体聚合的随机性及其共聚结构单元的复杂性 ,运用XPS及红外光谱等分析手段 ,探讨了共聚物铑配合物微观结构对催化性能的影响 ;研究了丙烯酸甲酯 2 乙烯基吡啶和丙烯酸甲酯 4 乙烯基吡啶两种共聚物与铑的不同配比的配合物的活性 ,考察了相同配比的共聚物配合物结构单元、温度等因素对消化活性的影响 ,为催化剂结构的合理设计提供了理论参考  相似文献   

14.
通过固相合成方法将聚酰胺-胺树状分子担载于氯球上,对其外围分别用2,4-二羟基苯甲醛和邻羟基苯甲醛进行修饰,再与SnCl2.2H2O反应,形成配体不同的两类树状高分子锡配合物.将此类配合物用作30%的双氧水氧化酮的Baeyer-Villiger反应的非均相催化剂,具有较好的催化活性.2-金刚烷酮、环己酮、3-甲基-2-戊酮等都转化为相应的酯和内酯,底物的转化率和产物选择性均较高.对2-羟基苯甲醛、2,4-二羟基苯甲醛和邻羟基苯甲醛修饰的不同类型催化剂催化下的反应进行比较,发现配体对锡的担载量和催化活性均有不同程度的影响.其中邻羟基苯甲醛修饰的配合物因具有较高的锡担载量而具有了最佳的催化活性.此催化体系使用环境友好的低浓度双氧水为氧化剂,催化剂制备方法简单、催化反应完成时间短、催化剂在多次重复利用后活性没有明显降低,可回收和重复利用.  相似文献   

15.
Abstract

Using a “chiral pool” approach, a number of chiral thiolate and sulfide ligands based on natural terpenes and terpenoids have been synthesized in a few simple steps. Two new Rh-thiolate complexes with the formula [Rh(CO)2(μ-SR)]2 were obtained. The influence of these complexes and catalytic systems formed by combining the synthesized ligands with [Rh(CO)2(μ-Cl)]2 and [Rh(cod)(μ-Cl)]2, on the reaction rate, chemoselectivity, stereoselectivity and formation of tetraphenyldisiloxane in Rh-catalyzed asymmetric hydrosilylation of acetophenone as a model reaction have been studied. Mechanistic aspects of formation of silyl enol ether as a side product in the presence of S-containing ligands are presented.  相似文献   

16.
我们曾报道一系列含有两种不同配位基团的高分子共聚物与四羰基二氯二铑形成的顺二羰基铑(Ⅰ)配合物。这些配合物在催化甲醇羰基化反应中显示出高催化活性和高稳定性。本文采用4-乙烯吡啶(Y)和丙烯酸甲酯(B)共聚物为配体,对其与四羰基二氯二铑形成的配合物(YBRh)进行了表征。对该系列配合物催化甲醇羰基化生成乙酸的性能进行了评价。  相似文献   

17.
Nano-sized phosphine and pyridine ligands having tetraphenylphenyl-, m-terphenyl-, poly(benzylether) moieties were synthesized. These ligands showed a remarkable effect on homogeneous transition metal catalyzed reactions. Pd(II) complexes with tetraphenylphenyl substituted pyridine ligands show high catalytic activities for oxidation of ketones suppressing Pd black formation and maintains the catalytic activity for a long time. Rh(I) complex catalysts with m-terphenyl substituted phosphine ligands showed remarkable rate acceleration in the hydrosilylation of ketones. In addition, several phosphinocalixarene ligands were synthesized and their coordination studies with Pd(II), Pt(II), Ru(II), Ir(I), and Rh(I) metals were documented. Ir(I) and Rh(I) cationic complexes with a 1,3,5-triphosphinocalix[6]arene ligand showed dynamic behavior with size-selective molecular recognition.  相似文献   

18.
The syntheses of three ligands are reported: N,N,N′,N′-tetra(2-hydroxyethyl)-1,3-propylene-diamine (1), N,N,N′,N′-tetra(2-hydroxyethyl)-1,10-decadiamine (2), N,N,N′,N′-tetra(2-hydroxyethyl)-1,4-xylyldiamine (3). The catalytic hydrolysis of p-nitrophenyl picolinate (PNPP) by the bivalent metal ion Cu(II) complexes of these ligands was studied kinetically in a buffered CTAB or Brij35 micellar solutions at 25 °C and different pH values. The results indicate that 1:2 and 2:1 complexes of these ligands and metal ion are the active species for the catalytic hydrolysis of PNPP in CATB and Brij35 micellar solutions. The ternary complex kinetic model for metallomicellar catalysis was employed to obtain the relative kinetic and thermodynamic parameters. The effects of the structure of the ligands and the microenvironment of reaction on the hydrolytic reaction of PNPP have been discussed in detail.  相似文献   

19.
The asymmetric hydroformylation of styrene catalysed by rhodium complexes modified by monodentate phosphepine ligands has been investigated. The effects of a systematic variation of the phosphorus substituent on catalytic activity and selectivity are reported as well as the outcome of a combinatorial approach for the formation of mixed ligands complexes with several commercially available ligands. Effective catalytic systems have been devised for the reaction that provide for full conversion within 24 h and regioselectivity up to 96% in the branched aldehyde and enantioselectivities up to 48%. The use of bidentate ligands built up by binaphthyl-supported seven-membered phosphacyclic units does not allow for further improvement in the reaction outcome.  相似文献   

20.
Starting from [{Rh(cod)Cl}(2)] and 1,3-dimesitylimidazole-2-ylidenes the novel [RhCl(cod)(carbene)] complexes 1-5 have been synthesized, characterized, and tested in the hydroaminomethylation of aromatic olefins. The influence of different ligands and reaction parameters on the catalytic activity was investigated in detail applying 1,1-diphenylethylene and piperidine as a model system. The scope and limitations of the novel catalysts is shown in the preparation of 16 biologically active 1-amino-3,3-diarylpropenes. In general, high chemo- and regioselectivity as well as good yields of the desired products were achieved.  相似文献   

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