Catalysis in Combustion

Catalysis and combustion have long been linked. In fact, the science of catalysis stems from Davy's discovery [1] that platinum wires could promote the flameless combustion of flammable fuel-air mixtures. Today, catalysis is a mainstay of our modern chemical industry. Oxidation catalysts are used not only for the complete oxidation of fuels to carbon dioxide and water, as in radiant catalytic tent heaters and fume abatement devices, but also for the selective partial oxidation of hydrocarbons or other “fuels” to produce basic chemicals such as ethylene oxide (from ethylene), terephthalic acid (from p-xylene), and nitric acid (from ammonia). However, despite the long-known capability of catalysts to oxidize hydrocarbons without significant production of carbon monoxide, soot, or thermal NO_x, there seemed little possibility that catalytic oxidation reactors could ever displace conventional flame combustors as primary fuel combustors. This is because the volumetric heat release rates of conventional catalytic oxidation reactors are far too low to be competitive with the flame combustor.     

2,4-二羟基苯甲酸铋对双基推进剂燃烧的催化作用

为了考察2,4-二羟基苯甲酸铋对双基推进剂燃烧的催化效果以及探索其催化作用机理,用螺压工艺制备了含2,4-二羟基苯甲酸铋的推进剂样品,研究了2,4-二羟基苯甲酸铋对双基推进剂燃烧的催化性能。结果表明,2,4-二羟基苯甲酸铋对双基系推进剂的燃烧具有良好的催化作用,能显著提高推进剂的燃速,并大大降低压力指数,与少量碳黑复合后,对提高推进剂的燃速效果更明显,铋盐、铜盐与碳黑三元复合后,催化效果更优。用快速热裂解固相原位池／傅里叶变换红外光谱（RSFT-IR）联用装置研究了2,4-二羟基苯甲酸铋的热分解机理,发现2,4-二羟基苯甲酸铋在催化推进剂燃烧过程中的活性组分为Bi2O3。     

催化燃烧式COD在线分析仪有关问题探讨

随着国家对环境保护的日益重视,要求化工厂对废水排放进行COD值在线检测.以往靠人工分析的常规重铬酸钾法,不仅测量周期较长,而且因人为不确定因素而易造成分析偏差,满足不了环保要求.     

燃烧催化剂对EMCDB推进剂交联固化反应的催化作用

设计了一种研究燃烧催化剂对EMCDB推进剂交联固化反应催化作用的实验方法，比较了十多种铅盐、铜盐对交联固化反应催化活性的强弱，筛选出了可用作粒铸EMCDB推进剂燃烧催化剂的铅盐、铜盐。实验结果表明，某些铅盐对交联固化反应有较强的催化加速作用，铜盐和炭黑对交 联固化反应没有明显的催化加速作用，只有对交联固化反应催化加速作用很小的铅盐才能用作EMCDB推进的燃料催化剂。     

稀土钙钛矿型燃煤催化剂的催化机理研究

稀土钙钛矿型催化剂是一类多功能催化剂,笔者简述了其结构性质,并对自制的催化剂进行XRD、SEM等实验,验证其主要成分为钙钛矿型氧化物、以及其表面孔隙发达满足用作催化剂的基本要求。最后结合热重分析实验,得出该催化剂对煤的燃烧有明显的促进作用,并且总结稀土钙钛矿型燃煤催化剂的催化燃烧的机理。     

Catalysis in Polymerization

Hardly a single polymerization process exists in which certain accelerating, regulating, and modifying ingredients are not used with great advantage even though they might be present only in very small quantities. In the early years of the art, when there did not yet exist a well-founded understanding of the mechanism of polymerization processes, the action of these ingredients and additives so much resembled the phenomenon of normal catalysis that the name catalysts was used for them. Today, in the clarifying hindsight of a rather well-developed theory of polymerization reactions, it is evident that in most cases the role of these substances during the formation of macromolecules does not fall in the domain of the classical definitions of the words catalysis and catalyst.     

Aerogels in Catalysis

Aerogels offer interesting opportunities for catalysis due to their unique morphological and chemical properties. These properties originate from their wet-chemical preparation by the solution-sol-gel (SSG) method and their subsequent liberation from the solvent via critical-point drying or supercritical (or hypercritical) drying (SCD). Due to the “structure-preserving” ability of SCD, the usually oxidic (or metallic) aerogels are solids of high porosity and specific surface area.     

Catalysis in Polymerization

Hardly a single polymerization process exists in which certain accelerating, regulating, and modifying ingredients are not used with great advantage even though they might be present only in very small quantities. In the early years of the art, when there did not yet exist a well-founded understanding of the mechanism of polymerization processes, the action of these ingredients and additives so much resembled the phenomenon of normal catalysis that the name catalysts was used for them. Today, in the clarifying hindsight of a rather well-developed theory of polymerization reactions, it is evident that in most cases the role of these substances during the formation of macromolecules does not fall in the domain of the classical definitions of the words catalysis and catalyst.     

波谱学在催化剂表征中的应用

介绍了红外光谱，拉曼光谱，核磁共振，X光电子能谱的表征能力及其在表征催化剂中的作用。红外和拉曼光谱可用于研究表面分子和载体结构；核磁共振可得到分子或原子团所处的化学环境；X光电子能谱可以了解元素的化学态，了解和掌握这些表征有助于进行催化剂的研究。     

Cooperative Catalysis: A New Development in Heterogeneous Catalysis

Whereas cooperative effect in catalysis, in which multiple chemical interactions participate cooperatively to achieve significant enhancement in catalytic activity and/or selectivity, is common in enzymatic reactions, it has been sparingly employed in heterogeneous catalytic systems. Here, some recent literature examples of abiotic catalysis, with emphasis on heterogeneous systems, that employ cooperation between acid and base and two metal centers are briefly described to demonstrate the principles involved. Since effective cooperation places strict demand on the positions of the different functional groups, new synthetic methods and strategies are needed to design and construct structures useful for cooperative catalysis. Recent progress in our laboratory in synthesizing new nanocage structures that possess molecular-size cavities, atomic layer thick, porous shells with internal functional groups is described. These recent developments suggest possibilities of new catalytic transformations that have not been attempted before. This is illustrated with two speculative examples utilizing cooperative catalysis: oxidative hydrolytic desulfurization and terminal carbon activation of hydrocarbon molecules.     

Nanoparticles in Catalysis

In this article, we report studies of two new forms of highly active supported catalysts. First, those derived from supported carbonylate clusters—nanocatalysts and second, those produced from the heterogenization of known chiral homogeneous systems. The utilization of established cluster compounds of precisely known composition and structure have proved invaluable in the preparation of mixed metal nanoparticles of well-defined composition. The attachment of these nanoparticles to the inner walls of mesoporous silica has led to the development of highly active and effective catalysts for a series of hydrogenation reactions, emphasizing the enhanced reactivity of these metal systems as a consequence of their size and of the low coordination numbers of the metal atoms involved. These attributes combined with the relative ease of characterization of both the active sites and their location has led to a detailed examination of the role of these nanosystems in a new approach to clean technology. In an alternative strategy, the use of heterogenized homogeneous chiral catalysts based on the ferrocenyl moiety and diamino ligands and linked to the inner surface of mesoporous materials either by a direct chemical bond or by an ionic interaction has also been explored. These catalysts have been shown to be highly effective in the enantioselective synthesis of organic compounds. Significantly, we have found that the mesopore (usually MCM-41) imposes spatial restrictions arising from the concavity of the inner surface and leads to greatly enhanced enantioselective (ee) performance.     

Aerogels in Catalysis

Aerogels offer interesting opportunities for catalysis due to their unique morphological and chemical properties. These properties originate from their wet-chemical preparation by the solution-sol-gel (SSG) method and their subsequent liberation from the solvent via critical-point drying or supercritical (or hypercritical) drying (SCD). Due to the “structure-preserving” ability of SCD, the usually oxidic (or metallic) aerogels are solids of high porosity and specific surface area.     

Monoliths in Heterogeneous Catalysis

The use of structured catalysts in the chemical industry has been considered for years. Conventional fixed-bed reactors have some obvious disadvantages such as maldistributions of various kinds (including a nonuniform access of reactants to the catalytic surface), high pressure drop in the bed, etc. Structured catalysts are promising as far as elimination of these setbacks is concerned. Two basic kinds of structured catalysts can be distinguished:

1. Structural packings covered with catalytically active material, similar in design to those used in distillation and absorption columns and/or static mixers. Good examples of catalysts of this kind are those offered by Sulzer, clearly developed by Sulzer column packings and static mixers. As in packed beds, there is an intensive radial convective mass transport over the entire cross-section of these packings. Structural packing catalysts and the reactors containing them are, however, not within the scope of this review.
2. Monolithic catalysts are continuous unitary structures which contain many small, mostly parallel passages. A ceramic or metallic support is coated with a layer of material in which active ingredients are dispersed. An interaction between these passages can occur if walls are permeable. The catalytically active material is present on or inside the walls of these passages. Radial mass transport can occur only by diffusion through the pores of the permeable walls.

     

催化与清洁工艺

全面分析了原子利用率、Ｅ－因子和环境系数,并利用它们作为化工过程新的评价指标。用实例分析证明催化技术可使精细化工成为清洁工艺     

Catalysis in VOC Abatement

Volatile organic compounds (VOCs) are harmful to environment and human health. Catalytic oxidation has been used in VOC abatement for over 60 years, and it has proven to be an effective technology. A large variety of VOCs set high demands for the treatment, and therefore catalytic oxidation needs still to be developed further. This paper reviews current aspects and future research needs related to VOCs and catalytic VOC treatment concentrating on solvent-based, chlorinated and sulphur-containing VOCs.