摘要:

Synthesis of ammonia on iron catalysts was discovered in 1905. Five years later, an iron catalyst containing two promoters, alumina and potassium oxide, was invented by a team of Badische Anilin und Soda Fabrik (BASF). The first high-pressure ammonia plant went on stream in 1913. Thus it took only 8 years between discovery, invention, and innovation, a remarkable record considering the novelty at the time of high-pressure operation [1]. Also noteworthy is the fact that the original BASF iron catalyst is still in use today although additional promoters are added to the two original ones in various commercial formulations [2]. In fact, recent advances in ammonia manufacture have been largely of an engineering nature [3]. This is so in spite of a very large amount of fundamental and applied work designed to elucidate the mechanism of the reaction and the surface chemistry of commercial or alternative catalysts.

ISSN:0161-4940    

DOI:10.1080/03602458108068066

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Exploratory and applied research in ammonia catalysis has two goals: to improve the activity and other desirable properties of the catalysts and to develop a variety of information required to obtain the best performance of the catalysts. In this latter category we have development of rate equations and parameters required to optimize reactor systems.

ISSN:0161-4940    

DOI:10.1080/03602458108068067

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

There are 105 large-scale plants in successful operation in virtually every corner of the globe. There are 20 more in various stages of design, engineering, or construction. Their capacities range from 600 to 1800 tons a day. These large-scale plants, and 20 earlier smaller Kellogg units, account for approximately half of the world's ammonia production today.

ISSN:0161-4940    

DOI:10.1080/03602458108068068

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

In earlier analyses [1–8] we have established a correlation between metal clusters and metal surfaces with chemisorbed molecules in the specific contexts of (1) the metal frameworks wherein the metal cluster core structures are fragments of cubic and hexagonal close packed or body centered cubic metal bulk structures; (2) ligand stereochemistry where the geometric features of ligands bound to clusters and to metal surfaces are similar; (3) thermodynamic features where the average bond energies for ligand-metal and metal-metal bonds are comparable, for a specific metal, in the metal cluster and the metal surface regime; and (4) mobility of ligands bonded to metal cluster frameworks and to metal surfaces. Nevertheless, there are sharp distinctions between surfaces and clusters. The average coordination numbers for metal-metal interactions and for metal-ligand interactions are distinctly different for clusters and for surfaces: generally, the former are larger for surfaces and the latter are larger for clusters. Additionally, the surface state is typically differentiated from the cluster state in the degree of coordination saturation—the metal atoms in the surface state are typically less coordinately saturated even for the states in which molecules or molecular fragments are chemisorbed at the surface than those metal atoms at the periphery of a molecular metal cluster. In the crucial chemical issue, metal surfaces are far more reactive than metal clusters. Metal surfaces exhibit a wide range and high level of catalytic activity whereas most metal clusters are catalytically inert, at least under modest reaction conditions, Most reported clusters are relatively stable and nonreactive; they are not the products of sophisticated synthesis procedures designed to generate highly reactive metal clusters. They commonly have been the products of reaction mixtures run at forcing conditions and are thermodynamically controlled, not kinetically controlled, products.

ISSN:0161-4940    

DOI:10.1080/03602458108068069

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Carboxylic acids can be synthesized by reacting olefins with carbon monoxide and water in the presence of a variety of transition transition metal catalysts:(1) Metals which have been employed as catalysts for this reaction include nickel, as first reported [1] by Reppe for the synthesis of acrylic and propionic acids from acetylene and ethylene, cobalt, iron, rhodium, ruthenium, palladium, and platinum [2]. The earlier studies of this reaction employed nickel, cobalt, and iron catalysts and required rather severe operating conditions, viz., 200-300 atm and 200-300°C. More recently the use of rhodium [3], iridium [4], platinum [5], palladium [6], and pyridine-promoted cobalt [7] catalysts has been reported. These latter systems all function at relatively mild reaction conditions (see Table 1).

ISSN:0161-4940    

DOI:10.1080/03602458108068070

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The past quarter century has witnessed an enormous transformation in the use of soluble transition metal complexes as catalysts in the chemical process industries. Until the mid-1950s, industrial use of homogeneous catalysis was largely confined to reactions of acetylene [1]. As indicated in Fig. 1, a large family of acetylene-based reactions was used to produce polymer intermediates such as vinyl acetate, vinyl chloride, acrylonitrile, chloroprene, and 1,4-butanediol. The processes were simple but they were relatively expensive because they were based on an expensive raw material. The large energy content of the acetylene molecule (ΔF°=50.84 kcal/mol) made it both hazardous to handle and expensive even in times when energy was cheaper.

ISSN:0161-4940    

DOI:10.1080/03602458108068071

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The epoxidation of olefins, while of considerable economic importance, forms a challenging problem to fundamental research in catalysis. When surveying the vast quantity of published material [1-6] two facts appear relevant.

ISSN:0161-4940    

DOI:10.1080/03602458108068072

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

The steps involved in developing commercially successful catalysts and the ways in which the techniques and technologies utilized have changed over time are described, primarily from the standpoint of the author's experiences during 20 years at Halcon/Scientific Design. The discussion is limited to the direct oxidation of ethylene to ethylene oxide in the vapor phase over catalysts containing silver.

ISSN:0161-4940    

DOI:10.1080/03602458108068073

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

With the advance of modern technology, it is becoming increasingly feasible economically to synthesize and produce on a large scale those chemical products, for example plastics, synthetic fibers, dye stuffs and paints, which are so much a part of our present day life.

ISSN:0161-4940    

DOI:10.1080/03602458108068074

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor

摘要:

Both the production of methane and methanol from CO and H2are important processes in chemical technology. They also have a distinguished history as the formation of methane was first reported by Sabatier and Senderens [1] in 1902. Methanol synthesis from CO and H2was first reported by Patart [2] in 1921, and in 1923 Badische Anilin and Soda Fabrik (BASF) announced the synthesis of CH3OH to the exclusion of other products [3]. The catalytic reactions that produced these two molecules, however, have been subjected to molecular scale studies only recently. We shall review here what is known about the kinetics and mechanisms of these reactions, about the catalytically active surface, and the nature of the surface chemical bond of CO, H2, and the reaction intermediates.

ISSN:0161-4940    

DOI:10.1080/03602458108068075

出版商:Taylor & Francis Group    

年代:1981

数据来源: Taylor