The kinetics of the synthesis of n-propyl-tert-butyl ether from isobutene and 1-propanol on sulfonated Amberlyst 15 copolymer in gas phase was investigated. The Langmuir-Hinshelwood equations were adjusted to the results of the kinetic experiment using the values of the adsorption equilibrium constants of the reactants from the adsorption measurements separately taken. Also, the equilibrium constants of the synthesis of ether from separate measurements were determined. The presence of both the effect of the maximum rate shift of the synthesis of n-propyl-tert-butyl ether with an increase in 1-propanol partial pressure and the effect of changing the order of the reaction in relation to 1-propanol, from the negative into the zero one with an increase in temperature, was found. The effects were accounted for by the change of the ratios of adsorption equilibrium constants of isobutene and 1-propanol depending on temperature. (c) 2006 Elsevier B.V. All rights reserved.