The kinetics of the synthesis of methyl-tert-butyl and ethyl-tert-butyl ethers from isobutene and alcohols (methanol and ethanol) on sulfonated Amberlyst 15 copolymer in the 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. The calculations were done by the Levenberg-Marquardt least-squares method accompanied by the Origin Microcal program. A single-stage mechanism of the synthesis of ethers consisting in the surf ace reaction between the molecule of alcohol adsorbed by one sulfonic group and the molecule of isobutene adsorbed by two sulfonic groups was suggested. (C) 2004 Elsevier B.V. All rights reserved.