The paper presents the study of methanol (MeOH) etherification, of 2-methyl-2-butene (2M2B) and of isomerization of 2-methyl-1-butene (2M1B) in presence of the macroporous cationite AMBERLYST-35((R)). The evaluation of the two equilibria based on literature of thermochemical data has allowed, computing, through algebraic combination, the equilibrium of tert-amyl, methyl ether (TAME) generation in the methanol addition to 2M1B. The values obtained are reviewed and compared with the experimental results for the liquid phase addition of methanol to 2M2B in presence,of Amberlyst-35((R)). (c) 2004 Elsevier B.V. All rights reserved.