Adsorption equilibrium constants of ethanol, methanol, isobutylene, isoamylenes (2M2B, 2M1B), MTBE and TAME on Amberlyst 15 catalyst were evaluated from the packed bed moment technique. Adsorption equilibrium constants of alcohols were found to be two orders of magnitude greater than the adsorption equilibrium constants of i-olefins and the corresponding tertiary ethers. However, their apparent heat of adsorption values are quite low (-6,7 kJ/mol and -8.3 kJ/mol for methanol and ethanol, respectively). Among the i-olefins, isobutylene gave the highest adsorption equilibrium constant and the heat of adsorption (-54.2 kJ/mol). The adsorption equilibrium constant of 2M2B on a catalyst, which was pretreated with ethanol, was about three times greater than the corresponding value obtained on fresh catalyst. Second moment analysis indicated that diffusion resistance in both macropores and microspheres of the catalyst are equally significant.