Meso-取代卟啉及其金属配合物的合成进展

为了筛选仿生催化氧化环己烷的催化剂,通过查阅相关文献,重点概述了Meso-取代卟啉及其金属配合物的合成方法。合成卟啉的方法有Rothemund法、Adler法及其改进法、Lindsey法等,合成金属卟啉的方法有＂一步法＂和：＂两步法＂,目前,＂两步法＂被普遍使用。     

Bridging Heterogeneous Catalysis and Electro-catalysis: Catalytic Reactions Involving Oxygen

Catalytic reactions that involve oxygen can be found in a large number of processes, including those in energy-related applications, in emission control and in processes important for the chemical industry. Whether the catalytic step is an oxygen insertion step as in a selective oxidation reaction, or an oxygen removal step as in a hydrodeoxygenation reaction, oxygen has proven to be a very challenging component, often determining the selectivity of the reaction. Some examples from our laboratories that bridge catalysis and electro-catalysis will be discussed, ranging from oxidative dehydrogenation of alkanes to oxygen reduction reaction in fuel cells.     

Metalloporphyrins in coal: 3. Porphyrins and metalloporphyrins in petrographic components of a subbituminous coal1

The distribution of metalloporphyrins in some petrographic components of a subbituminous coal (Janina, East High Silesian coal basin, Poland) were determined. The coal selected contains both iron and gallium porphyrins, and the concentration of each type was estimated in vitrain and durain. The gallium porphyrin content appeared to parallel the amount of vitrinite in the sample, but no correlation between iron porphyrin content and maceral was established. Indeed, the evidence suggests that the iron porphyrins may accumulate in maceral boundary regions. In small-scale experiments no metalloporphyrins were detected in exinite or fusinite macerals isolated from this coal. The results are briefly discussed.     

Molten Salt Catalysis of Gas Reactions

Molten salts have been used for many centuries in metal extraction, glass manufacture, and, more recently, in applications such as fused salt electrolysis. Usually dissociated into ions, they are often good solvents for oxides, carbides, nitrides, and metals. Their high thermal stability, low vapor pressure, good thermal and electrical conductivity, and low viscosity may be expected to confer on them an increasing technological importance in the future, and as a result research on their physical and chemical properties has grown markedly in recent years. Thermodynamic and transport properties [l-41 have been surveyed within the last decade, and Sundermeyer [5] has also reviewed their use as reaction media. A selection of catalytic reactions has been discussed by Kenney [6].     

Molten Salt Catalysis of Gas Reactions

Molten salts have been used for many centuries in metal extraction, glass manufacture, and, more recently, in applications such as fused salt electrolysis. Usually dissociated into ions, they are often good solvents for oxides, carbides, nitrides, and metals. Their high thermal stability, low vapor pressure, good thermal and electrical conductivity, and low viscosity may be expected to confer on them an increasing technological importance in the future, and as a result research on their physical and chemical properties has grown markedly in recent years. Thermodynamic and transport properties [l-41 have been surveyed within the last decade, and Sundermeyer [5] has also reviewed their use as reaction media. A selection of catalytic reactions has been discussed by Kenney [6].     

Oxygen in Catalysis on Transition Metal Oxides

Reactions of catalytic oxidation over oxide catalysts have been extensively studied in recent years following expansion of their applications in petrochemistry as well as their wide theoretical interest. Studies in this field have also contributed greatly to our understanding of the general mechanisms of catalyst action.     

Metal Carbonyls in Phase Transfer Catalysis

This review is limited to phase transfer systems (solid—liquid and liquid—liquid) involving metal carbonyls. The principles of phase transfer catalysis, related to metal carbonyl properties which play a key role in these two-phase systems, are first briefly recalled. Then, in the light of these principles, applications to inorganic chemistry (ligand exchange, preparation of metal carbonyl anions), organometallic chemistry (synthesis of π allyl complexes, clusters, orthometalated compounds, acylmetal carbonyls, complexed ylids), and finally to organic chemistry are comprehensively reviewed. In this last part, both stoichiometric and catalytic systems (with respect to the metal carbonyl) are reviewed essentially in the fields of functional reduction and carbonylation.     

Heterolytic and Homolytic Oxygen Transfer Reactions from d0 Metal Peroxides to Hydrocarbons

An attempt is made to correlate the catalytic activity of d⁰ metal complexes in the oxidation of hydrocarbons by H₂O₂ and ROOH with the oxidizing properties of their peroxidic derivatives. The triangular structure of bound peroxo and alkylperoxidic groups is a common characteristic of d⁰ metal peroxides. The heterolytic or homolytic nature of the catalytic oxidation is governed by the heterolytic or homolytic cleavage of the triangular peroxidic moiety. The mechanism of selective heterolytic epoxidation involves the peroxymetalation of the coordinated olefin. Homolytic oxidations are less selective and involve the non-stereospecific epoxidation of olefins and the hydroxylation of alkanes and arenes by biradical peroxidic species.     

有机合成中的相转移催化作用

随着国家建设发展的不断推进,人们的生活水平得到很大程度的提高,化工行业得到前所未有的发展。在这样的基础上研究有机合成物中的转移催化作用,需要从相应的操作原理进行分析,进而给出具体的应用。     

利用相转移催化剂合成刃天青

在相转移催化剂聚乙二醇-600催化下,以间苯二酚为主要原料,经氧化合成刃天青,优化了反应条件,找到对环境更友好、产率较高的合成方法。     

Continuous Oxygen Ion Transfer Medium as a Catalyst for High Selective Oxidative Dehydrogenation of Ethane

An oxygen permeable mixed ion and electron conducting membrane (OPMIECM) was used as an oxygen transfer medium as well as a catalyst for the oxidative dehydrogenation of ethane to produce ethylene. O^2- species transported through the membrane reacted with ethane to produce ethylene before it recombined to gaseous O², so that the deep oxidation of the products was greatly suppressed. As a result, 80% selectivity of ethylene at 84% ethane conversion was achieved, whereas 53.7% ethylene selectivity was obtained using a conventional fixed-bed reactor under the same reaction conditions with the same catalyst at 800 °C. A 100 h continuous operation of this process was carried out and the result indicates the feasibility for practical applications.     

Electron Transfer Reactions in Pulping Systems VIII. Reactions of Syringyl Alcohol in Aqueous Alkali

Syringyl alcohol, a simple lignin model compound, has been heated in lM NaOH at 135°. Five products - three monomers and two dimers - were identified from the reaction mixture; two of the products were presumably formed by radical processes. One of the radical products, 4-methylsyringol, was shown by deuterium labeling to incorporate a benzylic hydrogen from syringyl alcohol. Alkaline reactions of syringyl alcohol in the presence of radical initiators and inhibitors were not able to establish if the condensation reactions proceeded by a radical mechanism.     

卤代芳香族化合物氟化反应中的相转移催化

从相转移催化剂的种类、原理、反应条件以及它在卤代芳香族化合物氟化反应中的应用等方面对相转移催化剂的作用进行概括和总结。     

On the Role of Oxygen Storage in Three-Way Catalysis

The role of the so-called oxygen storage and release capacity (OSC) in promoting the activity of noble metals in the three-way catalysts (TWCs) is critically discussed. It is shown that the promoting effects of CeO₂ in the TWCs cannot be attributed to a simple redox type of effect according to the reaction CeO₂ ? CeO_{2 ? x} + x/2O₂, since multiple and sometimes intriguing effects of CeO₂ promoter have been observed, particularly in the latest generation of TWCs containing modified CeO₂–ZrO₂ mixed oxides.     

关于有机合成中的相转移催化作用分析

随着改革开放的发展,我国经济实力不断增强,人们的生活水平显著提升,物质文化需求也随之越来越高。为了更好的满足人们的需求和社会发展的需要,人们对化工业有了新的要求。在这种背景下,文章主要研究关于有机合成中的相转移催化作用,首先从理论基础出发,阐述了转化原理和反应条件,并列举了在有机合成物中的应用。希望可以通过本文论述,促进有机合成中的相转移催化作用的应用,也可以为相关行业提供借鉴作用。     

Catalysis of Transesterification Reactions by a Self-Assembled Nanosystem

Histidine-containing peptides self-assemble on the surface of monolayer protected gold nanoparticles to form a catalytic system for transesterification reactions. Self-assembly is a prerequisite for catalysis, since the isolated peptides do not display catalytic activity by themselves. A series of catalytic peptides and substrates are studied in order to understand the structural parameters that are of relevance to the catalytic efficiency of the system. It is shown that the distance between the His-residue and the anionic tail does not affect the catalytic activity. On the other hand, the catalytic His-residue is sensitive to the chemical nature of the flanking amino acid residues. In particular, the presence of polar Ser-residues causes a significant increase in activity. Finally, kinetic studies of a series of substrates reveal that substrates with a hydrophobic component are very suitable for this catalytic system.     

相转移催化合成BLP

研究了以聚乙二醇４００（ＰＥＧ－４００）为催化剂,以邻苯二甲酸酐、正丁醇、月桂醇为原料合成邻苯二甲酸丁基月桂酯（ＢＬＰ）的试验过程。探讨了催化剂用量、反应物配比、反应温度及时间对反应的影响,在最佳条件下,ＢＬＰ收率高达９０％ 。