Several industrial gas and certain liquid streams may contain one or more of H2S, COS and CO2 as well as CS2 and mercaptans. Aqueous solutions of amines are often used for treating these streams. H2S reacts with all amines (primary, secondary and tertiary) instantaneously; therefore its removal rate is always diffusion-controlled. Other compounds react with amines at finite rates necessitating a detailed knowledge of the kinetics of the reactions of CS2, COS and CO2 with amines.