1.2 Classification of Reaction Table 1.1 Classification of Chemical Reactions Useful in Reactor Design Noncatalytic Catalytic Homogeneous Most gas-phase reactions Most liquid-phase reactions Fast reactions such as Reactions in colloidal systems burning of a flame Enzyme and microbial reactions Burning of coal Ammonia synthesis Roasting of ores Oxidation of ammonia to pro- Attack of solids by acids duce nitric acid Heterogeneous Gas-liquid absorption Cracking of crude oil with reaction Oxidation of SO2 to SO; Reduction of iron ore to iron and steel 8 8 • 1.2 Classification of Reaction