Introduction to catalysis - Mechanisms and industrial applications

What would our world be like without catalysis? Whether we look at this question from the angle of life itself or from that of our modern society, the answers are identical. Without the fascinating power of catalysts to greatly accelerate the speed of reactions without being consumed, and thus to make biochemical reactions fast enough at the low temperatures of living organisms, life would be impossible. The same would be true of our modern society if man had not succeeded in harnessing this power, placing it at the service of the chemical industry, enabling it to manufacture a wide range of products in large quantities and at low cost. Initially limited to the production of basic inorganic compounds (sulfuric acid, ammonia, nitric acid, etc.), catalysis has gradually extended the scope of the chemical industry, playing an essential role in fields as diverse as petroleum refining, petrochemicals, specialty chemicals, fine chemicals, polymerization, pollution control, etc. This rightly raises questions about the relevance of Berzelius's 1835 choice of the term catalysis (from the Greek word καταλúeιν, with its negative connotations), which has nevertheless been adopted by all chemists and even integrated into common parlance.

As the brief history of catalysis shows, the first major applications, i.e. the production of basic inorganic compounds by heterogeneous catalysis, preceded the deciphering of the mechanism of catalytic reactions, with solid catalysts being chosen and optimized on a totally empirical basis. The time it took to establish the general mechanism of catalysis (almost a century) may seem long, but it has to be said that, at the time, this task presented real conceptual difficulties and, what's more, researchers had to overcome numerous practical obstacles: difficulty of access (to) and purification (of) reagents, solid catalysts with a small surface area and therefore limited activity, rudimentary apparatus, etc. At the same time, scientists discovering a new catalytic reaction were always trying to make the most of it. This combination of fundamental and applied concerns remains a natural constant in catalysis research.

The general characteristics of catalysis are now well defined. A multidisciplinary approach combining the methods and techniques of physical, inorganic and organic chemistry, surface and solid-state physics and chemical engineering has enabled us to establish the mechanism of many catalytic reactions: intermediate species, elementary steps in the catalytic cycle, characteristics of the species or active sites. The combination of this scientific knowledge and combinatorial techniques has accelerated the design, optimization and manufacture of catalysts with optimum activity, selectivity and stability.

The science...