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 406 毫秒
1.
硅氢加成反应是指在一定条件下含有硅氢键的化合物与含不饱和键的化合物进行的加成反应,是构筑C—Si键的重要反应之一,在有机硅工业中具有举足轻重的地位。该文综述了近年来金属-有机框架(MOFs)材料催化不饱和烃、羰基化合物和CO2的硅氢加成反应的研究进展,并针对每一种反应底物进行系统地总结与评述,最后指出了MOFs材料用于催化硅氢加成反应存在的问题,并对其未来发展方向进行了展望。  相似文献   

2.
4A分子筛固载铂催化剂催化乙炔硅氢加成反应   总被引:2,自引:0,他引:2  
研究了4A分子筛固载铂催化剂的制备及其催化乙炔与三乙氧基硅烷硅氢加成反应的反应规律,考察了反应温度、原料配比、催化剂铂含量、乙炔流量等对反应的影响.结果说明4A分子筛固载铂催化剂对乙炔与三乙氧基硅烷硅氢加成反应具有较好的催化活性,并且反应条件温和,催化剂回收利用3次仍具有较高的活性.  相似文献   

3.
以端氢基甲基苯基硅油和烯丙基缩水甘油醚为原料,在铂催化下通过硅氢加成反应制得端环氧基甲基苯基硅油;再在浓硫酸催化下,经甲醇醇解反应,得到端羟烷基甲基苯基硅油。研究了反应温度、反应时间、催化剂用量等对活性氢转化率的影响。结果表明,硅氢加成反应的最佳条件为:反应温度90℃,时间5 h,催化剂用量为反应物质量的0.015%,烯丙基缩水甘油醚中的CC与端氢基甲基苯基硅油中的Si—H的量之比为1.1∶1,此时,活性氢的转化率达94.87%;醇解反应的最佳反应时间为10 h。红外光谱与核磁共振光谱证实产物为端羟烷基甲基苯基硅油。  相似文献   

4.
以氯铂酸和二乙烯基四甲基二硅氧烷为原料,采用还原-配合法制得零价铂催化剂,并对催化剂的含量及其催化硅氢加成反应后体系的黏度、环氧值、反应效率(剩余氢质量分数)等性能进行表征。结果表明,该铂催化剂的催化活性和效率高,经济实用,其催化的硅氢加成反应产物的黏度和环氧值均保持稳定,进而可改善产品外观和稳定性。  相似文献   

5.
合成了聚苯乙烯-铂络合物,研究了它对不同类型不饱和化合物与甲基一氯硅烷及甲基氢二乙氧基硅烷硅氢加成反应的催化特性。结果表明,其催化活性和选择性受不饱和化合物的电子效应和空间位阻效应以及硅氯化试剂结构等多种因素的影响。聚苯乙烯-铂络合物对连有一个取代基的苯乙烯、丙烯酸甲酯与 氯硅烷及甲基氢二乙氧基硅 硅氢加成反应具有很高的催化活性,对连有两个取代基的甲基丙烯酸甲酯无催化活性;该催化剂可选择性催化烯丙  相似文献   

6.
氨基长链烷烃共改性聚硅氧烷的合成   总被引:3,自引:2,他引:3  
以α-蒎烯、甲基二氯硅烷、氯铂酸、甲醇、八甲基环四硅氧烷、N-β-氨乙基-γ-氨丙基甲基二甲氧基硅烷等为原料,通过硅氢加成反应、醇解反应和碱催化共聚反应合成了氨基蒎基改性聚硅氧烷。甲基二氯硅烷与α-蒎烯进行硅氢加成反应较佳的反应条件为反应温度80℃,甲基二氯硅烷与α-蒎烯的量之比1.1∶1,反应时间6h;采用石油醚为溶剂去除醇解反应产生的HCl。  相似文献   

7.
碳纳米管负载络合铂催化苯乙烯硅氢加成反应   总被引:4,自引:2,他引:4  
研究了碳纳米管负载聚乙二醇络合铂催化剂的制备及其催化苯乙烯与甲基二氯硅烷硅氢加成反应的反应规律。该催化剂在常温常压下有很高的催化活性,络合剂聚乙二醇能非常有效地提高β-加成产物苯乙基甲基二氯硅烷的选择性,30℃温度下反应195min,甲基二氯硅烷的转化率可达83 33%,β-加成产物选择性为100%;硅氢加成反应有一个明显的诱导期,诱导期过后反应迅速进行,反应温度等因素对诱导期有重要影响;催化剂性能稳定,回收使用3次无明显失活。  相似文献   

8.
比较了顺-二氯二氨合铂和氯铂酸对含氢硅油与端烯丙基聚醚的硅氢加成反应的催化作用。试验表明,在无溶剂体系中,顺-二氯二氨合铂能催化含氢硅油与端烯丙基聚醚的硅氢加成反应,且用量为2×10-6~5×10-6,仅为氯铂酸用量的十分之一,在70~130℃下反应4~6 h,产物几近无色、透明。  相似文献   

9.
冷帅  李云涛  邓建国 《化工进展》2018,37(10):3879-3884
采用溶剂热法合成了以三核碘化亚铜(CuI)四面体结构为活性中心的硅氢加成反应催化剂,探讨了物料比对产物收率的影响。结果说明了当配体与碘化亚铜的摩尔比为1:6时,产物收率最高。通过元素分析、傅里叶红外光谱分析、X射线光电子能谱分析、X射线单晶体衍射分析、紫外可见光光谱分析、热失重分析对配合物的化学组成、空间结构及性能进行表征,并进一步通过甲基苯基乙烯基树脂和甲基苯基含氢硅油的硅氢加成反应进行催化固化效果验证。结果说明了在催化剂填加量为0.04%、固化温度为150℃的优化条件下反应24h,共混体系固化效果最佳。该配合物对硅氢加成反应具有很好的催化性能,并且原料成本低、制备方法简单、晶体颗粒方便储存,有望解决硅氢加成反应中贵金属催化剂的高成本问题。  相似文献   

10.
高选择性催化合成苯乙基甲基二氯硅烷   总被引:2,自引:0,他引:2  
戴延凤  萧斌  李凤仪  茹翔 《化学试剂》2005,27(12):707-709,718
研究了5A分子筛负载聚乙二醇配合铂催化剂的制备及其催化苯乙烯与甲基二氯硅烷硅氢加成反应的反应规律.该催化剂在常温常压下有很高的催化活性,配合剂聚乙二醇能非常有效地提高β-加成产物苯乙基甲基二氯硅烷的选择性,在30℃下反应120min,甲基二氯硅烷的转化率可达87.15%,β-加成产物选择性为100%.硅氢加成反应有一个明显的诱导期,诱导期过后反应迅速进行,反应温度等因素对诱导期有重要影响.催化剂性能稳定,回收使用3次无明显失活.  相似文献   

11.
硅氢加成反应是合成有机硅材料最重要的途径之一,铂催化剂作为其应用最广的催化剂,具有重要的意义。本文首先介绍了硅氢加成反应机理的研究现状;分析了聚合物长链段铂配合物、含多个铂原子铂簇化合物及N-杂环卡宾铂配合物均相铂催化剂的研究进展,致力于改善均相催化剂催化选择性差、催化活性难以控制等缺点;分别阐述了不同铂催化剂载体如无机二氧化硅、炭载体、金属氧化物、有机高分子、固载液等作为铂催化剂载体的优点,负载铂催化剂具有可回收、产物选择性好的优点,有效解决了工业上铂损失的问题;最后对铂催化硅氢加成反应的发展趋势进行了展望分析,铂负载能力的提高、铂负载催化剂的分离、硅氢加成反应的原理、催化范围的扩大等均是今后研究的重要方向。  相似文献   

12.
《Reactive Polymers》1992,16(2):213-221
Two groups of resins bearing nitrile (CN) groups based on macroporous copolymers of acrylonitrile and divinylbenzene (AN/DVB) and terpolymers of styrene, acrylonitrile and divinylbenzene (S/AN/DVB) have been used as polymer matrices for the immobilization of Rh(I), Pt(II) and Pd(II) complexes. A group of four S/DVB resins functionalized with the CN ligands have been prepared and used for comparison. The resins differ in their chemical and physical structure, local concentration of the CN groups and their availability. Characterization of the heterogeneous complexes by IR spectroscopy confirmed the coordination of the metal ions to the polymer-CN ligands. The catalytic behaviour of the immobilized complex catalysts was tested in the hydrosilylation of 1-hexene. The activity of the polymer-bound catalysts strongly depends on the structure of the support used. The largest effect of the chemical structure of the polymer was found for the catalysts immobilized on the AN/DVB resins, while the polymer morphology played the major role in the high activity of the catalysts attached to the S/N/DVB resins. Lower activity was found for the systems bound to the functionalized S/DVB resins. Both polymer-supported Pt and Rh systems appeared to be highly effective for the hydrosilylation of the CC double bonds, but the platinum catalysts proved to be considerably more active. The rhodium catalysts were found efficient in the hydrosilylation of ketones. The immobilized Pd(II) complex was reduced to the metallic Pd by hydrosilanes. The supported Pt catalyst remained active when recycled 5 times, while the activity of the rhodium systems gradually decreased. The results offer the possibility of choosing the most suitable polymer matrix for the immobilization of metal complex catalysts for use in hydrosilylation and other catalytic reactions.  相似文献   

13.
The melt-phase hydrosilylation of terminal double bonds in polypropylene (PP) was investigated. The double bonds were generated by peroxide initiated degradation of PP in an extruder or a batch mixer. For this purpose, an organic peroxide, Lupersol 101, was employed in concentrations of 0.5–5 wt%. A hydride-terminated polydimethylsiloxane was employed as a model substance to investigate the feasibility of hydrosilylating the terminal double bonds of the degraded polypropylene. Reactive processing experiments were carried out in a hot press, a batch mixer, and a single screw extruder. Two different reaction mechanisms were used to initiate the hydrosilylation reaction: a radical chain addition mechanism and a platinum catalyzed mechanism using Karstedt's catlyst. For the radical mechanism, it was shown that catalytic amounts of a peroxide could initiate the addition of silanes to the double bonds of the degraded polypropylene. Furthermore, it was found that both reactions, degradation and hydrosilylation, could be performed simultaneously. For the catalytic mechanism, the required stabilization of the platinum colloid formed in this mechanism was accomplished by adding t-butylhydroperoxide as a cocatalyst. This melt-phase hydrosilylation route may be used to produce terminally functionalized polypropylenes, and a case study involving the terminal attachment of a styrene functionality was examined.  相似文献   

14.
This Account describes the development and mechanistic study of the cycloisomerization and cyclization/hydrosilylation of functionalized dienes catalyzed by cationic palladium(II) complexes. These transformations are characterized by good functional group compatibility, high regio- and stereoselectivity, and low air- and moisture-sensitivity. Mechanistic studies of palladium phenanthroline-catalyzed diene cycloisomerization and cyclization/hydrosilylation established mechanisms involving C-C bond formation via intramolecular carbometalation of an alkyl olefin chelate complex, which was directly observed in the context of cyclization/hydrosilylation.  相似文献   

15.
对二烷基咪唑类离子液体作为烯烃与三乙氧基氢硅烷硅氢加成反应的介质进行了研究.研究发现,二烷基咪唑类离子液体组成的阴、阳离子不同对烯烃与三乙氧基氢硅烷的反应有一定影响.离子液体为二烷基咪唑六氟磷酸盐时,咪唑环上取代烷基链长的增加,苯乙烯和三乙氧基氢硅烷加成反应中β加成物/α加成物的比值也随之增加.同时,二烷基咪唑类离子液体的阴离子件质也亢接影响了硅氢加成反应的发生.以[Bmim]PF6作为反应溶剂,反应完成后,离子液体催化剂体系可以比较容易地与产物分离,并可以重复使用.  相似文献   

16.
A series of carboxylated long chain polyethylene glycols(abbreviated as PEGCOOH) has been synthesized and used to support chloroplatinic acid.These supported catalysts were then tested for their efficiency in the hydrosilylation of alkenes.The factors affecting their catalytic properties,e.g.relative molecular mass of polyethylene glycol,reaction temperature,platinum content,and type of alkenes,have been studied.It was found that the activity of the platinum catalyst decreased with increasing length of the polyethylene glycol chain,and increased with reaction temperature.Moreover,these catalysts could be reused several times without a noticeable decrease in activity or selectivity.The reaction pathway leading to excellent selectivity for the β-adduct of hydrosilylation of alkenes with triethoxysilane catalyzed by this catalysis system was discussed.  相似文献   

17.
模拟过氧化物酶催化苯酚氧化降解的动力学   总被引:1,自引:0,他引:1  
为了研究模拟过氧化物酶催化降解苯酚的机理,一种大环金属配合物CuL(配体L:高氯酸-5,7,7,12,14,14-六甲基-1,4,8,11-四氮杂环-4,11-二烯)作为模拟过氧化物酶用于催化过氧化氢氧化苯酚的降解。用高效液相色谱法和分光光度法分析了苯酚催化氧化的主要产物和反应速率。根据实验结果提出了该催化反应的反应机理,并建立了相关的动力学模型。研究表明,大环铜金属配合物表现出过氧化物酶的催化作用特征。因此,所用大环铜配合物作为模拟过氧化物酶在催化苯酚氧化过程中是一种有效的催化剂。  相似文献   

18.
The hydrosilylation of cyclohexanone and acetone with triethysilane and diphenysilane catalyzed by polymer‐supported Rh(I) complex has been investigated. Two terpolymers of styrene, divinylbenzene, and 1‐vinylimidazole (S/DVB/VI) or N‐vinylpyrrolidinone (S/DVB/NVP) were used as the catalysts supports. Physical characterization of these materials has involved the measurements of the structural parameters in the dry and swollen states by DSC, the nitrogen BET adsorption method and inverse steric exclusion chromatography ISEC. From these results it can be concluded that the original polymer structure has been changed during the complex attachment giving rise to materials of higher porosity. X‐ray photoelectron spectroscopy XPS, IR, and AAS spectroscopy were used to characterization of heterogeneous complexes before and after use. The effect of the morphology of the support on the catalytic properties of the polymer‐supported Rh(I) species was tested in the hydrosilylation of ketones and correlated with the reaction mechanism. It was demonstrated that the high selectivity of homogeneous rhodium complex toward the silyl ethers can be partially reversed to the dehydrogenative silylation products by a proper choice of polymer support with favorable microporous structure. Recycling tests demonstrated high stability of the supported catalysts during prolonged use. The constant selectivity of the supported catalysts demonstrated during recycling experiments showed that they could be useful for practical application. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2012  相似文献   

19.
本文概述了通过不对称催化氢化和不对称催化氢化硅烷基化还原前手性亚胺类化合物中的C=N 的进展,并且着重从构成催化剂的金属中心的角度来介绍二茂Ti催化体系、Rh和Ir催化体系和Ru催化体系。  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