Zeolite-catalysed liquid-phase synthesis of isopropyl tert-butyl ether by the addition of 2-propanol to isobutene

The paper deals with the liquid-phase synthesis of isopropyl tert-butyl ether (IPTBE) from 2-propanol and isobutene over H-Beta, H-ZSM-5, and H-Y zeolites. The SiO2/Al2O3 ratio of tested zeolites was about 25 for H-Beta, 28 for H-ZSM-5, and 6 for H-Y. Experiments were performed in a batch reactor in the temperature range of 70-90 °C at 1.6 MPa. A comparative study of the behaviour of these catalysts was made at 80 °C by with an initial alcohol-to-isobutene molar ratio (RA/O) of 1. We optimised the activation process of the three zeolites by varying the temperature and time of calcination, thus selecting the experimental conditions of activation leading to the highest activity and selectivity. H-Beta was the most active and selective catalyst. Therefore, the kinetics of IPTBE synthesis was studied on H-Beta in the temperature range of 70-90 °C, with a RA/O varying from 0.7 to 2. The best kinetic model stems from a mechanism in which isobutene reacts with 2-propanol, with both adsorbed on one site, to give the ether adsorbed on one site. The apparent activation energy was estimated to be 92±12 kJmol−1.