Homogeneous catalysis basic concepts

The book presents a review of sixteen important topics in modem homogeneous catalysis. While the focus is on concepts, many key industrial processes and applications that are important in the laboratory synthesis of organic chemicals are used as real world examples. After an introduction to the field, the elementary steps needed for an understanding of the mechanistic aspects of the various catalytic reactions have been described. Chapter 3 gives the basics of kinetics, thus stressing that kinetics, so often neglected, is actually a key part of the foundation of catalysis. 

The basic concept is the intuition that, whether homogeneous or heterogeneous, catalysis is primarily a process controlled by a molecular phenomenon since it implies the catalyzed transformation of molecules into other molecules. It follows that on the surface of metals or metal oxides, sulfides, carbides, nitrides usually involved as heterogeneous catalysts, the relevant surface species and the mechanism of their mutual reactions must be of molecular character, as occurs in homogeneous or enzymatic catalysis. 

Basic Concepts of Homogeneous Catalysis of Electrode Reactions. . 672... 

The last two decades have seen enormous developments in catalyst discovery and optimization tools, notably in the area of high-throughput experimentation (HTE) and process optimization (5). However, the basic concept used for exploring the catalyst space in homogeneous catalysis has not changed Once an active catalyst complex is discovered, small modifications are made on the structure to try and screen the activity of neighboring complexes, covering the space much like an ink drop spreads on a sheet of paper. This is not a bad method, but can we do better with the new tools that are available today ... 

Some of the basic concepts and technologies are described here. Catalysis can be divided into two types (1) homogeneous and (2) heterogeneous reactions. In homogeneous reactions, the reaction occurs between similar species, e.g. liquid-liquid reactions. In heterogeneous reactions, the reaction occurs between different types of species, e.g. gas-solid, liquid-solid and liquid-gas. Many industrial reactions are heterogeneous gas-solid or liquid-solid reactions. We will concentrate first on gas reactions occurring at solid catalyst surfaces ... 

The basic notions of homogeneous catalysis have been amplified and discussed more extensively elsewhere, as have examinations of individual reaction steps. In briefly reviewing these concepts, we are constructing a framework in which to consider the activation of CO, COz, and NO by metal complexes in solution and homogeneously catalyzed conversions of these simple oxides. 

In this chapter we discuss some of the basic concepts of organometallic chemistry and reaction kinetics that are of special relevance to homogeneous catalysis. The catalytic activity of a metal complex is influenced by the characteristics of the central metal ions and the attached ligands. We first discuss the relevant properties of the metal ion and then the properties of a few typical ligands. 

This book is restricted essentially to aqueous-phase catalyses and thus to one area of the more comprehensively defined two-phase catalyses. This restriction to the most recent and successful development of homogeneous catalysis takes account of the rapid technical advances in the process concept first described by Manassen et al. in 1973, which was followed in rapid succession in the 1970s by hesitant basic work and in 1984 by the first commercial implementation. This unusual sequence - industrial implementation in a 100000 tonnes per year oxo plant for the hydroformylation of propylene before years of time-consuming basic research to determine mechanistic, kinetic and other data - demonstrates clearly the great leap forward that this process development represented in the field of homogeneous catalysis and in solving the central problem mentioned earlier. Since then... 

I n this chapter we discuss some of the basic chemical concepts that are of special relevance for homogeneous catalysis and metal complexes. Most homogeneous catalysts that we will discuss in this book are coordination or organometallic complexes of d elements. There are also a few complexes of f elements, i.e., lanthanides and actinides, that have shown promising catalytic activities, but their industrial use as homogeneous catalysts is insignificant. 

It is assumed that the reader has a basic knowledge of chemistry, in particular, of reaction kinetics and organometallic chemistry. Homogeneous transition metal catalysis and heterogeneous catalysis are treated on the basis of the most important catalyst concepts, and the apphcations of catalysts are discussed with many examples. The book aids practically oriented readers in becoming familiar with the processes... 

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