首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到19条相似文献,搜索用时 62 毫秒
1.
合成了一系列含有聚乙二聚链和季铵盐两种性中心的离分子相转移催化剂,并考察了它闪在正溴辛烷与固体碘化钠的亲核了以代反应中的相转移催化性能。  相似文献   

2.
本文考察了固载化聚乙二醇季铵盐作为相转移催化剂在咪唑N-烷基化反应,Williamson混合醚的合成以及卤素转换反应中的应用,着重研究了改变反应条件对催化反应的影响,就催化剂的重复使用能力和催化剂结构对其催化效率的影响也略作探讨。实验证明,本催化剂有较高的催化活性,有实际应用价值。  相似文献   

3.
聚合物固载相转移催化剂合成的进展   总被引:6,自引:0,他引:6  
杨建文  俞善信 《高分子通报》1993,(4):234-243,233
本文综述了近年来鎓盐、冠醚及穴醚、聚乙二醇及其衍生物、共溶剂和光活性季铵盐等5大类聚合物固载相转移催化剂的合成进展情况,并对其中某些催化剂的特点作了阐述。  相似文献   

4.
聚合物固载的聚乙二醇苄醚的相转移催化作用   总被引:2,自引:0,他引:2  
齐红彦  梁逊 《催化学报》1990,11(1):26-32
  相似文献   

5.
本文报道了聚苯乙烯固载聚乙二醇三相催化剂在卡宾的生成、酯化、假性紫罗兰酮、二茂铁、芳氧乙酸、对硝基茴香醇的合成和C、N-烃基化等反应中的应用,并对其催化机理进行了探讨.  相似文献   

6.
改进了聚苯乙烯固载化聚乙二醇苄醚的合成方法,并在正溴辛烷与固体NaI的亲核取代反应中考察了它们的相转移催化性能。结果表明,催化反应对n-C8H17Br浓度为表观1级。催化剂交联度越低,粒度越小,反应速率越大。大孔催化剂活性比凝胶催化剂高;聚乙二醇固载化后的活性比固载化前高,体系中水含量对反应速率也有影响。  相似文献   

7.
The gelatinous and macroporous phase transfer catalysts with multiple active centers were synthesized by means of quarterisation of PEG tertiary amine and chloromethylated St DVB copolymer. They were examined as phase transfer catalysts in the reaction of n C 8H 17 Br with solid NaI. The experimental results showed that the reaction rate was first order with respect to the concentration of n C 8H 17 Br. The effects of catalyst structure on the catalytic activity were also investigated. The observed reaction rate constant ( k obsd ) increased as the degree of cross linking of polymer decreased. Macroporous catalysts showed a higher activity (2~2 5 times) than that of microporous catalysts with the same degree of cross linking of polymer, particle size and amount of supported PEG. Molecular weight of PEG also showed much influence on k obsd . As molecular weight of PEG rose properly, the catalysts showed a higher activity. The results were discussed from the aspect of triphase catalysis reaction mechanism.  相似文献   

8.
改进了聚苯乙烯固栽化聚乙二醇苄醚的合成方法,并在正溴辛烷与固体NaI的亲核取代反应中考察了它们的相转移催化性能。结果表明,催化反应对n-C18H17Br浓度为表观1级,催化剂交联度越低,粒度越小,反应速率越小,大孔催化剂活性比凝胶催化剂高;聚乙二醇固载化后的活性比固栽化前高;体系中水含量对反应速率也有影响。  相似文献   

9.
聚合物固载相转移催化剂在有机合成中的应用   总被引:1,自引:0,他引:1  
本文综述了聚合物固载相转移催化剂在有机合成中的应用,包括亲核取代反、应、加成反应。消除反应、氧化还原反应等。  相似文献   

10.
聚苯乙烯固载聚乙二醇的合成及表征   总被引:4,自引:0,他引:4  
聚乙二醇在钠或浓氢氧化钠作用下接枝到氯甲基化聚苯乙烯树脂上,制成聚苯乙烯固载聚乙二醇树脂,讨论了影响接枝反应的条件.接枝反应的结果进行了电镜照片和红外光谱分析.  相似文献   

11.
BICENTRALPOLYMERSUPPORTEDPHASETRANSFERCATALYSTPOLYSTYRENE-SUPPORTEDPOLYETHYLENEGLYCOLANDPYRIDINIUMSALTYangJianwen(Instituteof...  相似文献   

12.
Reaction of polymethylene diamine with aroyl chloride and ammonium thiocyanate under the condition of solid–liquid phase-transfer catalysis using polyethylene glycol-400 (PEG-400) as the catalyst yielded polymethylene-bis-aroyl thiourea derivatives 3a–q in good-to-excellent yield. The products have been characterized by analytical and spectral (IR and H1 NMR) data.  相似文献   

13.
1. INTRODUCTION A variety of organic reactions have recently been reported to be catalysed by quaternary ammonium and phosphonium salts [1~4]. In same time, the attachment of phase-transfer catalysts to insoluble polymer supports greatly simplified their use in organic reactions [5~7]. The aim of this study was to investigate the effects of single and mixed ammonium and phosphonium salts, grafted on a 揼el-type?styrene-7% divinylbenzene copolymer, upon the phase-transfer catalytic process…  相似文献   

14.
In this study was to investigate,by phase-transfer catalysis,the activity of single and mixed ammonium and phosphonium salts grafted on a “gel-type“ stryene-7% divinylbenzene copolymer in the oxidation of benzyl alcohol with hydrogen peroxide.A wide variety of catalysts with different quaternary groups and different quaternary chain length substitutents were examined.The activity of single“onium“salts increases as a consequence of the association of ammonium and phosphonium salts grafted onn the same polymeric support.The activity of polymer-supported ammonium and phosphonium salts increases with the number of carbon atoms contained in the alkyl radicals of the -onium and of the functionalization degree with phosphonium groups.  相似文献   

15.
Four polymer-supported Fe-Co tetrametallic clusters have been prepared by ion exchange and ligand exchange. Their structures were characterized by IR, UV/visible diffuse reflectance spectra and elemental analysis, and by analogy with the reference cluster PhCH_2NMe_3FeCo_3 (CO)_2 . The four heterogenous clusters were efficient catalysts in the hydroformylation of 1-hexene, turnover numbers amounted to 823 —924 with the yield of 83.2—92.4% heptyl aldehydes and ratios of normal aldehyde to iso-aldehyde of 1.2—1.6, they are facilitated forming the normal aldehyde in comparison with the homogeneous analogue. For the polymer-supported clusters prepared by ion exchange, the polymer-cation parts had no obvious effect on the activity of the cluster anion. The polymer-phosphine substituted cluster prepared by ligand exchange was more stable than the clusters preparedby ion exchange.  相似文献   

16.
聚乙二醇/甲基丙烯酸β羟乙酯水凝胶的合成及其表征   总被引:1,自引:0,他引:1  
以偶氮二异丁腈(AIBN)为引发剂,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,采用自由基聚合法合成了聚乙二醇(PEG)/甲基丙烯酸β-羟乙酯(HEMA)水凝胶.应用傅立叶转换红外光谱(FT-IR)研究了水凝胶分子间的相互作用,结果表明PEG和HEMA间存在较强的分子闻氢键.  相似文献   

17.
研究了固载化聚乙二醇三相催化下香豆素的合成,探讨了影响反应的主要因素。结果表明,该反应的最佳反应条件为:水杨醛与碳酸钾的摩尔比为1:0.75,反应温度为175℃,反应时间为3.5h,该条件下香豆素的收率为65.7%。  相似文献   

18.
研究了固载化聚乙二醇三相催化下香豆素的合成,探讨了影响反应的主要因素。结果表明,该反应的最佳反应条件为:水杨醛与碳酸钾的摩尔比为 1: 0.75,反应温度为175℃,反应时间为3.5 h,该条件下香豆素的收率为 65.7%。  相似文献   

19.
端叠氮基聚乙二醇的合成与表征   总被引:3,自引:1,他引:2  
叠氮化物不仅具有重要的生理活性,如叠氮核苷(AZT),是目前治疗爱滋病(AIDS)的首选药物[1、2],而且也具有广泛的反应活性[3],如可还原成氨基;与炔烃可发生1,3偶极环加成反应;发生Curtius反应等.通过端叠氮基还原所获得的端氮基聚合物作为高分子载体在多肽液相合成中起着重要的作用[4,5].然而,目前在由醇类作为起始原料制备叠氮化物的过程中,仍大都采用对甲苯磺酸酯化或卤化,进而再叠氮化的反应[3].硝酸酯基是一种远未被人们充分认识的离去能力较强的基团,硝酸酯基化合物具有合成反应时间短、产率高、后处理容易等优点,因此,通…  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号