Catalytic reactions have four fundamental characteristics, derived from their definitions, which are crucial for understanding the function of catalysts.
1. Catalysts can only accelerate thermodynamically feasible reactions. When developing new chemical reaction catalysts, a thermodynamic analysis must first be performed to determine if the reaction is thermodynamically viable.
2. Catalysts can only accelerate a reaction towards equilibrium; they cannot change the equilibrium position (equilibrium constant).
3. Catalysts exhibit selectivity. When a reaction can proceed in more than one direction, the catalyst accelerates only one of them, thus promoting both reaction rate and selectivity in a unified manner.
4. Catalyst lifetime. Catalysts can alter the rate of a chemical reaction. Ideally, catalysts are unaffected by the reaction. However, in actual reactions, catalysts are subjected to prolonged heating and chemical action, leading to irreversible physicochemical changes.
