双金属催化剂体系催化过氧化氢分解反应

研究了双金属催化剂体系催化过氧化氢分解反应,测量了不同催化剂体系的活化能.结果表明,双金属催化剂对过氧化氢分解反应具有良好的催化性能,且双金属催化剂存在协同催化作用;而酸性环境对过氧化氢催化分解有明显的抑制作用.     

Pd-N-杂环卡宾化合物催化的Heck反应、Suzuki反应进展

Pd催化的C—C键偶联反应是形成碳—碳单键的重要反应之一.传统上,使用膦化合物为配体来调整催化活性及选择性.但大多数Pd-膦化合物对空气稳定性差,容易被氧化;在溶液中易于解离出膦配体而降低催化剂稳定性,通常需要给反应体系中加入较多的膦配体以保持催化剂的稳定性和活性.1991年发现的稳定N-杂环卡宾(NHC)类配体具有富含电子、给电子能力强,对金属配位能力强,结构易修饰等特点,使得金属-NHC化合物成为金属有机化学、催化等领域研究新的焦点.Pd-NHC化合物已经可催化多类有机反应,是继传统Pd-膦催化剂外的又一类高效催化剂.综述了近年来不同结构的NHC如单齿简单NHC、双齿NHC、含其它配位原子的NHC等配体与Pd的配合物在Heck反应、Suzuki反应等偶联反应中的应用.     

不对称Henry反应的研究进展

总结了各种能有效催化不对称Henry反应的新方法、新条件和新催化剂,讨论了一类拓展的不对称催化Henry反应。对立体选择性催化Henry反应的催化剂的发展提出了作者的一些看法。参考文献26篇。     

《精细化学品催化合成技术(下册):催化合成反应与技术》

《精细化学品催化合成技术》分上、下两册,上册(第1~6章)为"绿色催化技术",下册(第7~14章)为"催化合成反应与技术"。本册(下册)在上册叙述精细化学品合成的绿色催化技术基础上详细介绍了各种类型催化剂参与的各种类型有机合成反应。包括在多孔本体和负载金属催化剂上使用氢气的有机化合物催化加氢和催化加氢裂解反应;在酸碱催化剂上进行精细化学品催化合成反应;使用分子氧和过氧化物作为氧源的催化氧化反应;使用手性辅助试剂催化合成手性化     

烯烃氢甲酰化反应研究进展

本文综述了烯烃氢甲酰化反应的催化剂从钴配合物到铑配合物和从均相催化体系到两相催化体系的发展过程。比较了三种催化剂和两个催化体系的特点、应用情况及研究工作进展.     

反应控制相转移催化研究的进展

反应控制相转移催化是近年来发展起来的一类新的催化体系.该催化体系在反应过程中具有均相催化的本征,当反应结束后,催化剂发生相的变化而从反应介质中析出,从而可实现催化剂的分离和循环使用.本文就反应控制相转移催化原理及其在烯烃环氧化、醇氧化、烯烃断键氧化、苯羟基化、硒催化羰基化和酯化反应等方面应用的最新进展进行了综述.     

非均相催化臭氧氧化反应机制

臭氧催化氧化作为高级氧化技术是目前水处理领域研究的热点,其中非均相臭氧催化氧化技术因其氧化能力强、降低臭氧投加量特别是能显著提高有机物矿化率等优点而备受关注。非均相催化臭氧氧化领域不断研究新的催化剂,但是其反应过程及机制更加复杂。催化臭氧氧化的性能很大程度上取决于催化剂及其表面性质。污染物在催化剂表面形成络合物,或者臭氧在催化剂表面分解产生不同的含氧物种如表面氧原子、过氧化物和羟基自由基等。本文评述了非均相臭氧催化氧化反应中存在的多种机理,主要是自由基理论、氧空位理论、表面原子氧理论、表面络合物理论和臭氧直接氧化理论。催化剂表面的羟基基团是主要的催化活性中心,本文探讨了表面羟基基团催化反应机制,得出催化剂表面性质决定其表面活性位点的特性及含量,对诱导臭氧分解产生含氧活性物种起了关键作用;概述了催化剂改性后的结构形态、比表面积及其性能和作用机制;并讨论了非均相臭氧催化氧化反应催化剂未来的发展趋势,为催化臭氧氧化污水处理技术提供了理论参考。     

腐植酸负载Pd/Ni双金属催化剂对Heck反应催化性能的研究

制备了腐植酸负载Pd/Ni双金属催化剂, 该催化剂能够成功催化溴苯与丙烯酸、苯乙烯等乙烯基化合物的Heck反应, 产率均在85%以上; 催化剂能够不同程度地重复使用, 在催化溴苯与丙烯酸反应中, 催化剂重复使用3次后仍可得到42.9%的产率, 而在催化溴苯与苯乙烯反应中, 催化剂重复使用7次后也可得到26.7%的产率; 并且对不同取代基芳基卤与丙烯酸的反应也有很好的催化活性.     

Ni催化的Suzuki偶联反应

本文主要对Ni催化的Suzuki偶联反应的发展历程和近年来碳卤键断裂类、碳氧键断裂类、碳碳键断裂类、碳氮键断裂类和碳硫键断裂类Ni催化Suzuki偶联反应进行总结。通过近十年研究,各类新型催化剂、配体、添加剂不断被开发,使反应活性大为提高,反应条件越来越温和。对目前认为Ni催化的Suzuki偶联反应的机理进行了梳理,发现Ni催化的Suzuki偶联反应催化剂循环方式有两种,即Ni(0)/Ni(Ⅱ)循环和Ni(Ⅰ)/Ni(Ⅲ)循环。因此,本文认为研究和发展价廉的金属Ni催化剂是研究Suzuki偶联反应的一个重要方向,未来Ni催化Suzuki偶联反应的研究将会集中在机理探究、新型催化剂和配体设计、多类型碳碳键构建(Csp~2-Csp~3、Csp~3-Csp~3)以及广泛底物的不对称Ni催化的Suzuki偶联反应。     

新型高效乙酸丁酯合成固体酸催化剂及其反应工艺

酯化反应是精细化学工业中极为重要的一类反应 ,目前工业上均在硫酸液相催化下直接酯化制取。硫酸腐蚀反应器 ,污染环境 ,随着环保法规的不断完善 ,开发可替代硫酸的新型催化体系已成为现代化学工业中普遍关注的新趋势。目前的研究工作主要集中在以固体酸 (尤其是 SO2 - 4/Mx Oy 型固体酸 )替代硫酸催化酯化反应 [1～ 8]。我们制得了一种新型 SO2 - 4/Fe2 O3- Zr O2 - Si O2 催化剂[9] ,该催化剂催化乙酸 /丁醇酯化反应表现出良好的转化率、选择性、酯收率。考察了反应温度、反应时间、催化剂加入量等对乙酸 /丁醇酯化反应的影响 ,并考…     

Boehmite@tryptophan‐Pd nanoparticles: A new catalyst for C–C bond formation

A boehmite@tryptophan‐Pd nanoparticulate catalyst was prepared by a simple, fast and convenient route. The nanomaterial was characterized using various techniques and employed as a thermally stable catalyst for Heck, Stille and Suzuki cross‐coupling reactions. Optimized conditions for these reactions are described. The catalyst could be isolated, post‐reaction, by simple filtration and recycled for several consecutive cycles without a notable change in its activity.     

Proton transfer reactions for improved peptide characterisation

The combination of deprotonation (via ion/molecule and ion/ion reactions) and low-energy collision-induced dissociation (CID) has been explored for the enhanced characterisation of tryptic peptides via access to different precursor charge states. This approach allows instant access to fragmentation properties of singly and doubly protonated precursors (arising from the availability of mobile protons) in a single experiment. Considering both charge states extended our base of structurally informative data (in comparison with considering just a single charge state) due to generation of additional sequence ions and by obtaining supplementary structural information derived from selective cleavages. Roughly 37% of combined data sets (CID spectra of doubly and singly charged precursor) showed a greater database identification confidence than each set alone. Moreover, comparison between a number of sequence ions of the singly charged precursor and the doubly charged precursor provided a mean of distinguishing the two classes of tryptic peptides (arginine or lysine containing).     

含有酯基二茂铁亚胺环钯化合物催化Suzuki和Heck反应

合成并表征了系列含有酯基二茂铁亚胺环钯化合物.结果表明,该系列环钯催化剂在纯水或有机溶剂中均能高效催化Heck和Suzuki偶联反应.     

Enzymatic Promiscuity： Escherichia coli BioH Esterase-catalysed Aldol Reaction and Knoevenagel Reaction

Esterase BioH,which is obligatory for biotin synthesis in Escherichia coli,was found to exhibit a promiscuous ability to catalyse Aldol and Knoevenagel reactions with moderate to good yields.The reaction conditions including organic solvent,molar ratio of ketone to aldehyde,enzyme amount,and reaction time were investigated to evaluate the effect of different reaction conditions on yield.Target compounds were afforded in the best yield of 91.2％ for Aldol reaction and 54.7％ for Knoevenagel reaction.In addition,because the enzyme could be prepared with a low cost,this protocol could provide an economic route to conduct Aldol and Knoevenagel reactions,which expand the field of enzymatic promiscuity.     

Gas-phase conjugation to arginine residues in polypeptide ions via N-hydroxysuccinimide ester-based reagent ions

Gas-phase conjugation to unprotonated arginine side-chains via N-hydroxysuccinimide (NHS) esters is demonstrated through both charge reduction and charge inversion ion/ion reactions. The unprotonated guanidino group of arginine can serve as a strong nucleophile, resulting in the facile displacement of NHS from NHS esters with concomitant covalent modification of the arginine residue. This reactivity is analogous to that observed with unprotonated primary amines such as the N-terminus or ε-amino group of lysine. In solution, however, the arginine residues tend to be protonated at pH values low enough to prevent hydrolysis of NHS esters, which would render them relatively unreactive with NHS esters. This work demonstrates novel means for gas-phase conjugation to arginine side chains in polypeptide ions.     

Construction of the bicyclo[3.3.1]nonenone core by successive Michael reactions of 2-cyclohexenone derivatives

Construction of the bicyclo[3.3.1]nonenone core was achieved by stepwise annulation of 2-cyclohexenone derivatives and acrylates via successive Michael reactions. The process could also be effected by a one-pot procedure.     

苯炔参与的去芳构化反应研究进展

去芳构化反应是有机化学热点研究领域之一,可从二维平面分子出发构筑高官能团化的三维立体分子.近年来,苯炔作为一类高活性中间体被有机化学家们广泛用于去芳构化反应研究中,并取得了一系列创新成果.从含氮芳杂环同苯炔的去芳构化反应、苯炔与双烯体的[4+2]环加成去芳构化反应以及苯炔以其它途径参与的去芳构化反应三个方面,对机理进行...     

Recent Advances of Single-atom Catalysts for Electro-catalysis

Single-atom catalysis is the “hot spot” in the field of catalysis due to the special geometries, electronic states, and their unique catalytic performance. Single-atom catalysts(SACs), isolated metal atoms dispersed on the support, show the highest atom efficiency, cutting down the potential cost in the industrial process. Consequently, this “homo-hetero” catalyst could be a promising candidate for the next-generation catalysts. The applications for the SACs are widely reported, like gas-solid reactions, organic reactions, and electro-catalysis. In this mini- review, we will focus on the recent work of SACs on electro-catalysis, including hydrogen evolution reaction(HER), oxygen reduction reaction(ORR), oxygen evolution reaction(OER), CO₂ reduction reaction(CO₂ RR), and nitrogen reduction reaction(NRR).     

Preparation and characterization of Cu supported on 2-(1H-benzo[d]imidazol-2-yl)aniline-functionalized Fe3O4 nanoparticles as a novel magnetic catalyst for Ullmann and Suzuki cross-coupling reactions

Copper supported on 2-(1H-benzo[d]imidazol-2-yl)aniline (BIA)-functionalized Fe₃O₄ nanoparticles (Cu-BIA-Si-Fe₃O₄) as a novel magnetic catalyst was designed and used for the synthesis of new products via Ullmann and Suzuki cross-coupling reactions. The Ullmann reaction was performed by mixing arylboronic acid with aniline derivatives in dimethylsulfoxide solvent. Also, diaryls were synthesized via Suzuki C–C reactions between aryl halides and phenylboronic acid in the same solvent. The prepared materials and catalyst were characterized with various analytical techniques. The Cu-BIA-Si-Fe₃O₄ catalyst demonstrated catalytic efficiency with good to excellent yields for both types of reactions in comparison with commercial palladium catalysts. Also, the catalyst could be recovered by a simple filtration and retained its activity even after several cycles.     

胺作为配体在钯催化偶联反应中应用

对近期我们研究小组及其它研究小组在利用胺作为钯催化偶联反应的配体研究进展进行了总结. 钯/胺作为催化体系主要应用的偶联反应包括: Suzuki-Miyaura交叉反应, Sonogashira交叉反应, Stille交叉反应, Hiyama交叉反应和Heck反应. 研究结果表明胺可以作为价廉和高效的配体促进钯催化交叉偶联反应.