MTBE synthesis, from methanol and iso-butylene, is studied in a novel Riser Simulator using a ZSM-5 catalyst. Conditions selected for the operation of the Riser Simulator unit are as follows: 1-5 catalyst/reactant ratios, 80 to 160 degrees C temperatures, 1.09 methanol/iso-butylene mol ratio, 25 to 34 kPa methanol partial pressures and 10 to 120 s reaction times. Injection of methanol, with enough time for the methanol to reach adsorption equilibrium, followed by an isobutylene injection is found to be the best operating mode to achieve 100% iso-butylene selectivity toward MTBE with 4 to 6.8% isobutylene conversions. With the gathered experimental data, a reaction rate model based on the Rideal-Eley kinetic model is successfully developed.