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超临界流体状态下的异构烷烃与烯烃烷基化反应 总被引:21,自引:1,他引:21
成功地应用固体酸催化剂在超临界反应条件下进行了异构烷烃与丁烯的烷基化反应。在超临界反应条件下,固体酸催化剂在1400h的反应以后,仍保持100%的烯烃转化率。探索出一个解决固体酸催化剂在烷基化反应中极易失活的有效方法。探讨了超临界流体抑制固体酸催化剂结炭失活的机制和烷基化反应中选择超临界反应条件的规律。 相似文献
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以胺和醇为原料,在Ni-Sn/Al2O3催化下液相合成氮烷基胺类化合物。反应工艺为连续式反应,醇既是烷基化试剂,又是供氢体和溶剂。考察了180 ℃下不同的胺与各类醇在Ni-Sn/Al2O3催化作用下的氮烷基化反应。研究表明该烷基化反应具有普遍的适用性,多数胺与甲醇、乙醇、正丁醇反应,具有较高的氮烷基化总产率。一些胺与醇反应产率甚至在99%以上。本文作了催化剂稳定性测试,并通过XRD和TEM对催化剂进行了表征,分析了催化剂失活的原因。研究表明,该催化剂具有很高的稳定性可保持高活性超过480 h,Lewis酸中心是氮烷基化反应的活性中心,随着反应进行,Lewis酸中心转化为Brφnested酸中心,致使催化剂活性降低。 相似文献
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A New procedure to prepare superacid perfluorooctanesulfonic acid (POSA) is reported. POSA catalyzed Friedel-Crafts alkylation of aromatic compounds with alkyl halides in liquid-phase reactions. Alkylation gave higher total yields than the corresponding reactions with Nafion-H, without the need of any complex decomposition or work-up. The reactions do not need to be carried out under absolutely anhydrous condition. The catalyst POSA can be easily separated from the reaction mixture and reused or recovered. The reactivity of the alkylation reagents and the mechanism of the reaction are discussed. 相似文献
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α-Alkylation of ketones with styrene derivatives was developed using a mesitylcopper-dppp complex as a soft Brønsted base catalyst. No waste derived from the alkylating reagent was produced in this catalytic alkylation reaction. The bisphosphine ligand structure, as well as the reaction solvent, had profound effects on catalyst activity. The reaction proceeded under mild conditions from a range of ketones and styrene derivatives. The present catalysis is especially useful for the selective mono-alkylation of ketones. 相似文献
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MCM-41固载Co席夫碱配合物的制备及其催化烯烃环氧化的研究 总被引:6,自引:1,他引:6
环氧化合物作为有机合成中间体具有广泛应用,催化烯烃环氧化一直是催化化学中的一个重要课题[1~2].尽管已经报道了以过酸、过氧化氢、烷基过氧化物、或分子氧为氧化剂,以金属配合物(通常为钌、钼、钛的配合物)为催化剂的反应体系,但对环氧化物的选择性却很低[3].另外,除了需探索具有高选择性的催化体系外,应用分子氧或空气作为氧化剂更适宜于经济和安全的要求.目前,在以分子氧作为氧化剂,均相催化烯烃环氧化的研究中,应用醛类化合物作为氧转移试剂是一种有效的和方便的促进烯烃环氧化的方法[4].但是,均相催化剂难于分离和重复使用,因此… 相似文献
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利用电纺丝技术制备出苯乙烯-丙烯腈共聚物负载钯的纳米丝催化剂.对催化剂进行了SEM、TEM、IR和XPS的测试.所制备的催化剂对α-己烯催化氢化结果表明,该催化剂在常温、氢气常压下具有很高的催化活性和较好的重复使用性,并且催化氢化过程中存在烯烃的异构化反应.实验结果表明,反应时间为150min时纳米催化剂A对α-己烯催化加氢生成正己烷的转化率是传统催化剂PdCl2/-γAl2O3的4.7倍. 相似文献
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通过二茂铁甲醛与丙二胺反应得到双二茂铁基醛亚胺配体N~1,N~3-双二茂铁亚甲基丙烷-1, 3-二胺(FcMP), FcMP与MoO_2Cl_2(THF)_2的四氢呋喃溶液作用, 合成了双二茂铁基醛亚胺钼(VI)配合物. 以配合物为催化剂, 叔丁基过氧化氢为氧化剂, 分别以苯乙烯和环己烯为底物, 考察了温度、时间、催化剂量及溶剂对于烯烃均相环氧化反应的催化性能的影响. 结果表明, 在最优实验条件下, 反应12 h, 环己烯的转化率为88%, 环氧环己烷的选择性为98%;苯乙烯的转化率为84%, 氧化苯乙烯的选择性为76%. 催化剂经简单分离可回收使用, 且催化活性基本保持不变. 同时对环氧化反应的机理进行了初步探讨. 相似文献
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S. M. Islam Paramita Mondal Sanghamitra Mukherjee Anupam Sigha Roy Asim Bhaumik 《先进技术聚合物》2011,22(6):933-941
A new heterogeneous Schiff base copper(II) complex was prepared by reacting amino‐polystyrene with salicylaldehyde followed by complexation with cupric chloride. The structure of this immobilized complex has been established on the basis of scanning electron microscope (SEM), thermogravimetric analysis (TGA), elemental analysis employing atomic absorption spectroscopy (AAS), and spectrometric methods like diffuse reflectance spectra of solid (DRS) and fourier transform infrared spectroscopy (FTIR). Catalytic activity of this polymer anchored Cu(II) complex was tested by studying the oxidation of cyclohexene, styrene, and benzyl alcohol in the presence of tert‐ butylhydroperoxide as oxidant. Several parameters such as solvent, oxidant, reaction time, reaction temperature, amount of catalyst, and substrates oxidant ratio were varied to optimize the reaction condition. Under optimized reaction conditions, cyclohexene gave a maximum of 74% conversion with three major products 2‐cyclohexene‐1‐one, cyclohexene epoxide, and 2‐cyclohexene‐1‐ol. The conversions of styrene and benzylalcohol proceed with 53% and 77%, respectively. Styrene gives styrene epoxide as the major product while benzylalcohol gives benzaldehyde as the major product. The catalytic results reveal that polymer anchored copper(II) Schiff base complex can be recycled more than five times without much loss in the catalytic activity. Copyright © 2009 John Wiley & Sons, Ltd. 相似文献
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Johnson JB Bercot EA Rowley JM Coates GW Rovis T 《Journal of the American Chemical Society》2007,129(9):2718-2725
Results from a mechanistic study on the Ni(COD)2-bipy-catalyzed alkylation of anhydrides are consistent with turnover-limiting reductive elimination at high Et2Zn concentrations. While the presence of styrene does not affect the initial rate of alkylation, it appears to inhibit catalyst decomposition and provides higher product yield at long reaction times. In contrast, Ni(COD)2-iPrPHOX-catalyzed anhydride alkylation proceeds through two competing catalytic cycles differentiated by the presence of styrene. The presence of styrene in this system appears to accelerate rate-limiting oxidative addition and promotes the cycle which proceeds 4 times more rapidly and with much higher enantioselectivity than its styrene-lacking counterpart. 相似文献
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An enantioselective synthesis of allylic esters has been achieved by a novel asymmetric alkylation of allylic gem-dicarboxylates. The catalyst derived from palladium(0) and R,R-1,2-di(2'-diphenylphosphinobenzamido)cyclohexene efficiently induced the alkylation process with a variety of nucleophiles to provide allylic esters as products in good yield. High regio- and enantioselectivities were observed in the alkylation with most nucleophiles derived from malonate, whereas a modest level of ee's was obtained in the reactions with less reactive nucleophiles such as bis(phenylsulfonyl)ethane. In the latter case, a slow addition procedure proved effective, leading to significantly improved ee's. The utility of the alkylation products was demonstrated by several synthetically useful transformations including allylic isomerizations, allylic alkylations, and Claisen rearrangements. Using these reactions, the chirality of the initial allylic carbon-oxygen bond could be transferred to new carbon-oxygen, carbon-carbon, or carbon-nitrogen bonds in a predictable fashion with high stereochemical fidelity. The conversion of gem-diesters to chiral esters by the substitution reaction is the equivalent of an asymmetric carbonyl addition by stabilized nucleophiles. In conjunction with the subsequent reactions that occur with high stereospecificity, allylic gem-dicarboxylates serve as synthons for a double allylic transformation. 相似文献
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Saravanakumar Elangovan Dr. Jean‐Baptiste Sortais Prof. Dr. Matthias Beller Prof. Dr. Christophe Darcel 《Angewandte Chemie (International ed. in English)》2015,54(48):14483-14486
A general and benign iron‐catalyzed α‐alkylation reaction of ketones with primary alcohols has been developed. The key to success of the reaction is the use of a Knölker‐type complex as catalyst (2 mol %) in the presence of Cs2CO3 as base (10 mol %) under hydrogen‐borrowing conditions. Using 2‐aminobenzyl alcohol as alkylation reagent allows for the “green” synthesis of quinoline derivatives. 相似文献