Poly(styrene) Resin‐Supported Cobalt(III) Salen Cyclic Oligomers as Active Heterogeneous HKR Catalysts

A cross‐linked poly(styrene) support functionalized with cobalt(III) salen cyclic oligomers that can be used as a catalyst for the hydrolytic kinetic resolution (HKR) of terminal epoxides is reported. This catalyst is the most active heterogeneous catalyst to date for the HKR of terminal epoxides and can be recycled more than six times with excellent enantioselectivities for the HKR of epichlorohydrin. A 3‐fold rate enhancement was observed when conducting the HKR reaction with 6 equivalents of water compared to 0.6 equivalents. We hypothesize that this rate enhancement is due to water sequestration of the diol product from the organic phase, thereby maintaining a high local concentration of epoxides and catalyst in the organic phase.     

绿色化学中的新催化方法

本文简述了绿色化学中几种有前景的新催化方法，包括固体酸取代液体酸的酸催化，晶格氧代替分子氧的氧化，TS－1分子筛H2O2的清洁氧化新工艺及羰化催化的新发展。     

催化氢酯基化反应的研究进展

介绍了氢酯基化反应及其特点,分别综述了均相催化氢酯基化反应和多相催化氢酯基化反应的研究现状,并对不对称催化氢酯基化的研究提出了建议。     

Iron(II)‐based catalysts for ethene oligomerization

The synthesis of iron(II) complexes with various tridentate di(imino)pyridine ligands and their potential as ethene oligomerization catalysts are described. The ligands are characterized by ¹H‐ and ¹³C‐NMR spectroscopy and the complexes only by mass spectrometry due to their paramagnetism. After activation either with methylalumoxane (MAO) or with a heterogeneous cocatalyst consisting of partially hydrolyzed trimethylaluminum and silica gel, the prepared complexes proved to be good catalysts for the oligomerization of ethene. 1‐Octene, 1‐hexene, and 1‐decene were the major products, formed in very high isomeric purity (99.9 %). © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 88: 476–482, 2003     

Pd（OAc）2／CuI共催化杂环C—H键与芳基溴的直接芳基化反应研究

研究开发了一个实用高效的Pd（OAc）2／CuI共催化体系,只需在1％Pd（OAc）2,10％CuI,0．5mol PPh3配体存在下,苯并唑类杂环与各种芳基溴的直接芳基化反应就能够在温和的反应条件下顺利进行,并得到良好的收率。     

Pd（OAc）2/CuI共催化杂环C—H键与芳基溴的直接芳基化反应研究

研究开发了一个实用高效的Pd(OAc)2/CuI共催化体系,只需在1%Pd(OAc)2,10%CuI,0.5 mol PPh3配体存在下,苯并唑类杂环与各种芳基溴的直接芳基化反应就能够在温和的反应条件下顺利进行,并得到良好的收率。     

烯烃氢甲酰化反应催化剂的研究进展

综述了烯烃氢甲酰化反应的催化剂体系 ,通过对发展较成熟的烯烃氢甲酰化均相催化体系缺点的分析 ,引入近 2 0年来发展起来的水溶性膦配体和过渡性金属配位生成的水 /有机两相催化体系 ,对其催化机理、优点和最新发展动态进行了评述 ;最后重点介绍了负载水相催化体系的组成、优点、水溶性配体和已报道的此类催化剂。     

硫基烯烃的合成新方法

硫基烯烃是具有一定活性的烯类化合物,介绍了硫基烯烃的合成新方法——金属络合物催化法和碱催化法。金属络合物催化和碱催化的含硫化合物与炔烃反应可生成立体选择性、高效性产物,是近年来研究催化法的热点,为碳-硫的构建提供了有效途径。     

激光催化氧化甲烷合成化合物的研究进展

天然气储量丰富,日益成为重要的清洁能源之一,而从其主要成分甲烷合成高附加值化合物更是研究前沿。由于甲烷结构稳定,CH键能很高,因而活化甲烷需要的条件非常苛刻。本文首先介绍了普通光催化氧化甲烷合成化合物的反应原理、研究进展、催化反应器和存在不足,然后综述了激光催化氧化甲烷合成化合物的反应原理、研究进展和催化反应器。指出激光光源具有提高光催化剂量子效率和缩短催化反应时间等诸多优势,接下来在深入研究激光催化反应机理的基础上,通过设计科学合理的激光反应体系,并遴选高效的光催化剂,有望显著提升包括甲烷氧化在内的激光催化反应性能,从而具有重要的学术意义和实践价值。今后的重点研究方向是通过激光催化氧化的方法使甲烷在温和的条件下活化,并合成高附加值化合物。     

中孔分子筛催化剂的研究进展

从4个方面回顾中孔分子筛催化剂的研究进展①代替传统酸催化剂催化大分子裂解,Friedel-Crafts的烷基化和酰基化反应;②向其骨架中引入Na+,Cs+等碱金属离子制得碱性催化剂催化Knoevenagel缩合反应;③引入Ti,Sn及Pt等过渡金属元素制得氧化还原催化剂以提高对大分子氧化反应的选择性;④负载其他活性物质.指出今后应在增加“中孔墙”的结晶度,增强酸性和增大孔径等方面做进一步的研究.     

Catalytic Asymmetric Allylation of 3‐Aryloxindoles by Merging Palladium Catalysis and Asymmetric H‐Bonding Catalysis

A catalytic asymmetric allylic alkylation reaction of 3‐aryloxindoles was accomplished via a dual catalysis merging palladium catalysis and asymmetric H‐bonding catalysis for the first time. Using this approach, allylated oxindoles bearing chiral all‐carbon quaternary centers were produced in high yields with good enantioselectivities (up to 92 % yield and 96:4 er).

     

Chemo‐Catalyzed Pathways to Lactic Acid and Lactates

Lactic acid is an important building block for the production of biodegradable polymers (PLLA, PDLA, etc.) as well as starting material for the pharmaceutical industry. The current production of this chiral compound is dominated by fermentation processes. However many catalytic reactions that could be used for manufacturing lactic acid were developed in the past three decades. High reaction rates and simple separation of products in comparison to fermentation characterize many of these processes. Excellent stereoselectivities up to 99% ee could be achieved. This review aims to give a critical overview of chemical processes applying catalysis as an alternative for the production of both enantiomerically pure and racemic lactic acid and lactates. The efficiency and economy of these processes are analyzed.

     

New Paradigms and Future Critical Directions in Heterogeneous Catalysis and Multifunctional Reactors

Heterogeneous catalysis is a key pillar of the global industrial chemical and petrochemical sector, and 85% of all chemical products are produced with at least one catalytic step. Indeed, catalysis and catalytic reactors are a critical underpinning science for energy, environmental, and economic security. This paper reviews some future critical directions for research in catalysis science, toward a greener and more sustainable future. We believe that even a relatively mature field as heterogeneous catalysis and nanomaterials can be vitalized and spurred by major discoveries, but an outside-the-box thinking and a focused effort in a large plurality of disciplines is necessary. Thus, critical research needs in several areas, including heterogeneous and homogeneous catalysis, biocatalysis, photocatalysis, electrochemical conversions, and computational catalysis, are reviewed. The research needs of the future lie at the intersection of synthesis of novel nanostructured materials with tunable pore size distribution, controlled porosity, and high surface area; development of new catalytic applications for such materials; and the science of advanced characterization including in situ spatiotemporal analysis. In the area of computational catalysis, we believe that the future lies in the development of hybrid methods (parallel and serial) which can model the typical multiscale phenomena that are typically encountered in protein translocation and signal transduction, charge transport, enzymatic catalysis, surface chemistry, and self-assembly in complex fluids. As we promulgate the new directions to the catalysis fraternity, some prior research areas will unfortunately need to be relegated to obsolescence, to maintain a healthy balance on the research forefront.     

Rate Acceleration of Solid‐Liquid Phase‐Transfer Catalysis by Rotor‐Stator Homogenizer

A rotor‐stator homogenizer was found to be an effective mixing tool that accelerated solid‐liquid phase‐transfer reactions. In the asymmetric alkylation under phase‐transfer conditions using the homogenizer, a considerably high turnover frequency was observed.

     

New concepts for a new generation Claus alumina

We have developed a new Claus alumina which presents a particular ultramacroporosity, between 0.1 and 1 μm (to reduce diffusional constraints) and a well-defined soda content (below 2500 ppm Na₂O) to reduce the sulfation of the surface and, thus, prolong the life of the catalyst.     

相转移催化水解法制备苯甲醇的研究

在相转移催化剂存在下,用氯化苄与羧酸盐反应生成酯,再用30％氢氧化钠水解羧酸苄酸即可得到苯甲醇,水解母液循环使用。研究了催化中类与用量、投料比等因素对苯甲醇收率的影响。在最佳条件下,收率可达95％。