Comparative study of TAME synthesis on ion-exchange resin beads and a fibrous ion-exchange catalyst

The reaction rates to tert.-amyl methyl ether (TAME) with the ion-exchange resin bead catalysts (A16, A35 and XE586) and a fibrous catalyst (SMOPEX-101) were measured as a function of temperature (323-353 K) with stoichiometric amount of reagents fed to a continuous stirred tank reactor. When the reaction rates were assessed against the weight or acid capacities of the catalysts, the activity order was A35 > A 16 > SMOPEX-101 > XE586. When the rates were calculated versus the square of the acid capacity, the activities of the catalysts were similar. This indicated a dual-site mechanism. The rates of TAME formation and the isomerisation of isoamylenes as a function of temperature (333-353 K) and the feed MeOH/isoamylene molar ratio (0.5-2.0), as well as the decomposition of TAME, were then measured in a batch reactor with the ion-exchange fibre (SMOPEX-101) as catalyst. Kinetic modelling results favoured a single-site mechanism for the isomerisation and a dual-site mechanism for the etherification. The activation energy was determined to be 116.7 U mol(-1) for the isomerisation of 2M1B to 2M2B, 92.7 kJ mol(-1) for the etherification of 2M1B to TAME and 93.0 kJ mol(-1) for the etherification of 2M2B to TAME. (C) 2003 Elsevier Science B.V. All rights reserved.