ABSTRACT
The idea of a catalyst is one of the most fascinating and significant in science and the word is one of the few that have carried over broadly from scientific into nonscientific language. A catalyst speeds up a chemical reaction without being consumed substantially-the occurrence of a reaction accelerated by a catalyst is called catalysis. At first, one might think that catalysis seems too good to be true, but the principles are well understood; a catalyst works by forming chemical bonds with reactants, generating intermediates that react more readily to give products than the reactants would alone-and giving back the catalyst. A catalyst affects the rate of approach to equilibrium of a reaction but not the position of the equilibrium. Catalysts provide subtle control of chemical conversions; a good catalyst increases the rate of a desired reaction but not the rates of undesired side reactions. Catalysis is ubiquitous in biology and technology and is the key to the efficiency of most chemical conversions. Only temperature provides a comparable means for increasing reaction rates, but high temperatures are often unacceptable-for example, because they harm biological organisms; high temperatures in chemical technology often mean high costs, e.g., because reaction in a liquid at high temperature requires a high pressure to maintain the liquid state, and high-pressure equipment is expensive.
