SYNTHESIS OF TERTIARY AMYL METHYL-ETHER (TAME) BY ACID CATALYSIS - KINETICS AND EQUILIBRIA OF 2-METHYL-2-BUTENE METHOXYLATION

Tertiary amyl methyl ether (TAME) has been prepared by methoxylation of a pure C5 isoolefin with good selectivity. A polymer-supported sulfinic acid proved to be the best catalyst. The isomerization of 2-methyl-1-butene and 2-methyl-2-butene has been studied under methoxylation conditions of the isoolefin, since they are the decomposition products of TAME; in both cases the major isomer obtained is 2-methyl-2-butene (92-97%). The methoxylation kinetics of 2-methyl-2-butene in the temperature range 55-90°C show a reversible reaction, with an equilibrium constant decreasing from 4.48 (55°C) to 1.09 (at 90°C). Consistent results are obtained for the enthalpy of TAME formation (-41.17 kJ mol-1) and decomposition (+40.54 kJ mol-1) and for activation energy of the forward (E1 = 81.09 kJ mol-1) and reverse (E = 114.95 kJ mol-1) reactions.