联二萘酚双钠盐催化的Henry反应研究

Henry反应是重要的形成碳碳键的反应之一,在有机合成中有着广泛应用.通常的henry反应催化剂为强酸或者强碱,能否找到一种温和的催化剂来催化此反应呢?通过筛选,我们发现在催化剂量的联二萘酚双钠盐(3 mol %)存在下,henry反应能够快速的进行,产率高达100%.此催化剂催化的henry反应不但反应迅速而且条件温和.     

Designing Pd-based supported bimetallic catalysts for environmental applications

Supported bimetallic nanoparticulate catalysts are an important class of heterogeneous catalysts for many reactions including selective oxidation, hydrogenation/hydrogenolysis, reforming, biomass conversion reactions, and many more. The activity, selectivity, and stability of these catalysts depend on their structural features including particle size, composition, and morphology. In this review, we present important structural features relevant to supported bimetallic catalysts focusing on Pd-based bimetallic systems and recently reported strategies to control them through different synthesis methodologies. Further, we focus on a few reactions that are relevant to environmental catalysis, i.e. CO oxidation, hydrocarbon oxidation, hydrodechlorination, and NO _x decomposition, where Pd-based catalysts are often used successfully. In spite of much progress in these areas, still there is a need for more advanced catalytic technologies to address the grand challenges like environmental remediation. Some of the recent advances in the design of bimetallic catalysts were made because of the combined efforts of material scientists, spectroscopists, microscopists, catalysis chemists, and engineers through state-of-the-art characterization methodologies, mechanistic investigations, and structure-activity correlations. This review is aimed at inspiring scientists to rationally design catalysts for a green and sustainable future.     

烯烃复分解反应--2005年诺贝尔化学奖综述

烯烃复分解反应是指在金属卡宾化合物的催化作用下,烯烃里的碳—碳双键被拆散、交换、重组,形成新分子的过程。法国的肖万提出了烯烃复分解反应的基本机制;美国的施罗克和格拉布二人继承和发展了肖万的烯烃复分解反应机制,研制出了有效、实用的催化剂。新的合成过程更简单快捷,生产效率更高,副产品更少,产生的有害废物也更少,有利于保护环境,每天都惠及人类。     

Solid acid catalysts in Green Chemistry

In the first part of this article, the principles of functioning of the solid acid catalysts, their nature and preparation of a few types were described. In this part, some practical examples of such catalysts employed in the synthesis of several organic compounds are presented, which illustrate the extent to which catalysts help reduce pollution, cut costs of production, etc., that are important principles of Green Chemistry. Leena Rao is Reader, Department of Chemistry, SIES College of Arts, Science and Commerce, Sion, Mumbai. Her current research interests are green technologies in synthetic organic chemistry. She is actively associated with Bombay Association of Science Educaion, Mumbai.     

Strecker反应机理研究进展

Strecker反应由于在制备α-氨基酸及其衍生物领域存在巨大的应用潜力,有关其机理及有机催化的研究一直是近几年的热点。重点综述了Strecker反应的影响因素及有机催化下的反应原理。影响Strecker反应的因素主要来自三个方面：醛酮组分、胺组分、氰化物组分。有机不对称的Strecker反应是借助于有机小分子催化剂与反应底物之间氢键作用来完成的,通过高立体选择性诱导来有效地活化醛羰基、酮羰基、shiff碱等,从而实现不对称催化。以后研究该反应的重点将是丰富氰化物、有机不对称催化剂的种类及有机催化下反应的机理。     

一种新的脯氨酸衍生物类手性催化剂的合成

以脯氨酸为原料合成的一系列有机小分子化合物,在催化丙酮和苯甲醛的不对称反应中催化作用明显.而以L-脯氨酸为原料,通过氨基保护、羧基酯化、格氏反应、去保护4步反应,得到手性催化剂4步的总产率为43%.其结构经HNMR确证.     

ZrO_2/SO_4~(2-)类固体超强酸的制备及其在有机合成中的应用

简要介绍了ZrO_2/SO_4~(2-)类固体超强酸的制备及其改性;综述了近年来此类催化剂以其独特的不溶性、酸性、活性、选择性在有机合成反应中的广泛应用.     

芳胺重氮化在有机合成中的应用

重氮化的重要性在于重氮盐的化学性质非常活泼,重氮盐可进行许多反应,转化成许多类型的化合物可发生多种反应.重氮盐作为有机合成反应的中间体,在有机合成中占有极其重要的位置.     

Metathesis: A “Change-Your-Partners” dance

On 5th October 2005, The Royal Swedish Academy of Sciences decided to award the Nobel Prize in Chemistry for 2005 jointly to Yves Chauvin, Institute of French Petroleum, France, Robert H Grubbs, California Institute of Technology, USA and Richard R Schrock, Massachusetts Institute of Technology, USA for the development of the metathesis method in organic synthesis. This increasingly important organic process allows researchers to synthesize certain kinds of complex molecules that were previously difficult and inefficient to make. Their research has opened the door to faster and more efficient methods for developing new drugs and polymers. Imagination will soon be the only limit to what molecules can be built in the laboratory!     

钯催化Suzuki反应的研究进展

钯催化Suzuki偶联反应是有机合成中构建分子中碳-碳键的重要反应之一,由于该反应产物容易分离、催化剂可重复使用等特点,已引起人们的广泛关注.综述了近年来钯催化Su-zuki反应的研究进展,包括Suzuki反应机理、载体催化剂及其在有机合成中的应用等.     

Woodward’s synthesis of vitamin B<Subscript>12</Subscript>

The synthesis of this molecule was a landmark in organic synthesis. It involved the masterful control of shapes of molecules to create 9 chiral centres with known absolute and relative configurations. The concepts of absolute and induced asymmetric synthesis are here explained.     

The 2010 chemistry nobel prize: Pd(0)-catalyzed organic synthesis

The 2010 Nobel Prize in Chemistry was awarded to three scientists, R F Heck, E-I Negishi and A Suzuki, for their work on “Palladium — Catalyzed Cross Couplings in Organic Synthesis”. It pertains to research done over a period of four decades. The synthetic procedures embodied in their work enable construction of C-C bond selectively between complex molecules as in simple ones at desired positions without disturbing any functional groups at other parts of the reacting molecules. The work finds wide applications in the synthesis of pharmaceuticals, agricultural chemicals, and molecules for electronics and other applications. It would not have been possible to synthesize some of the complex natural products or synthetic compounds without using these coupling reactions in one ormore steps.     

离子液体中Heck反应的研究进展

过渡金属钯催化的Heck反应是碳碳偶联反应中最重要的反应之一．绿色化学是当前化学领域研究的热点和前沿,离子液体是理想的绿色溶剂．近年来在离子液体中进行Heck反应受到广泛关注并取得了一定进展．文巾就近几年离子液体中的Heck反应进行了综述．     

有机合成反应选择性及其控制策略

有机合成是化学研究领域中最具有魅力的。结构复杂、性质多元、应用广泛的有机物及其合成方法学,让人赞叹与探求。文章用科学方法论总结了有机合成中的化学选择性、区域选择性和立体选择性的规律及其热力学和动力学控制策略,提出了综合利用其控制原理解释或预测竞争性反应产物的基本方法。     

离子液体中Suzuki反应的研究进展

过渡金属钯催化的Suzuki反应是碳-碳偶联反应中最重要的反应之一。绿色化学是当前化学领域研究的热点和前沿,离子液体是理想的绿色溶剂。近年来在离子液体中进行Suzuki反应受到广泛关注并取得了一定进展。本文就近几年离子液体中的Suzuki反应进行了综述。     

Impact of diesel emission fluid soaking on the performance of Cu-zeolite catalysts for diesel NH<Subscript>3</Subscript>-SCR systems

Diesel emission fluid (DEF) soaking and urea deposits on selective catalytic reduction (SCR) catalysts are critical issues for real diesel engine NH₃-SCR systems. To investigate the impact of DEF soaking and urea deposits on SCR catalyst performance, fresh Cu-zeolite catalyst samples were drilled from a full-size SCR catalyst. Those samples were impregnated with DEF solutions and subsequently hydrothermally treated to simulate DEF soaking and urea deposits on real SCR catalysts during diesel engine operations. Their SCR performance was then evaluated in a flow reactor with a four-step test protocol. Test results show that the DEF soaking leached some Cu from the SCR catalysts and slightly reduced their Cu loadings. The loss of Cu and associated metal sites on the catalysts weakened their catalytic oxidation abilities and caused lower NO/NH₃ oxidation and lower high-temperature N₂O selectivity. Lower Cu loading also made the catalysts less active to the decomposition of surface ammonium nitrates and decreased low-temperature N₂O selectivity. Cu loss during DEF impregnation released more acid sites on the surface of the catalysts and increased their acidities, and more NH₃ was able to be adsorbed and involved in SCR reactions at medium and high temperatures. Due to lower NH₃ oxidation and higher NH₃ storage, the DEF-impregnated SCR catalyst samples showed higher NO _x conversion above 400 °C compared with the non-soaked one. The negative impact of urea deposits during DEF impregnation was not clearly observed, because the high-temperature hydrothermal treatment helped to remove the urea deposits.     

Solid acid catalysts in green chemistry

This article deals with various ‘supported’ acid catalysts developed as alternatives for the conventional ones in organic synthesis. They have advantages such as producing less toxic waste and using less energy.     

SiO_2气凝胶钼尾矿金属催化剂的应用研究

利用商洛钼尾矿与亲水型Si O2气凝胶结合制成的气凝胶钼尾矿催化剂对甲醇与乙醇一步合成异丁醛、仲丁醇的氧化反应的催化活性进行考察。通过改变催化剂的用量和反应时间考察催化剂的催化活性。用傅立叶变换红外光谱仪对产物进行分析。结果表明:甲醇与乙醇一步合成异丁醛的反应在2 h时有醛基吸收峰;仲丁醇氧化反应在2 h时有羰基吸收峰;说明此催化剂对这两个反应均有一定活性。     

固相化学反应的热力学分析及其优势探讨

从热力学角度分析了固相反应的吉布斯自由能变,印证了固相反应一旦发生,便能进行到底的结论.并且,探讨了固相反应在化学合成和保护环境等方面较液相反应具有非常明显的优势.     

溶剂法聚苯乙烯/粘土纳米复合材料的研究

介绍了采用大分子溶液直接插层有机粘土制备聚苯乙烯／粘土纳米复合材料合成技术．实验结果表明：聚苯乙烯大分子链在柠烯溶液中有着极好的溶剂化作用，与改性有机粘土能够发生有效插层作用，同时粘土剥离物增强材料可以纳米级尺寸均匀分布在聚合物基体．阐述了插层剂选择及有关阳离子表面活性剂分子修饰原则及合成原理以及重点讨论了聚合物溶液直接插层原理及热力学条件和影响因素。