Liquid-phase synthesis of isopropyl tert-butyl ether by addition of 2-propanol to isobutene on the oversulfonated ion-exchange resin Amberlyst-35

The selectivity and kinetics of the liquid-phase addition of 2-propanol to isobutene to give isopropyl tert-butyl ether (IPTBE) was investigated in a batch reactor over the commercial oversulfonated ion-exchange Amberlyst-35 resin in the temperature range 60–90 °C and 1.6 MPa for 2-propanol/isobutene initial ratios ranging from 0.5 to 3.0. The effect of the initial 2-propanol/isobutene molar ratio and temperature on isobutene conversion (XIB), IPTBE yield (YIPTBE/IB) and selectivity to dimers (SIPTBE/DIM) and on the initial reaction rate of IPTBE formation (r0IPTBE) was also evaluated. Amberlyst-35 was found to be more active than Amberlyst-15 and medium-pore H-exchanged zeolites for carrying out IPTBE synthesis. Experimental IPTBE formation rates can be successfully represented by two kinetic models derived from the LHHW and ER formalisms, where 2-propanol adsorbed on one active site reacts with isobutene, either adsorbed on one active site in the former model, or in liquid-state in the latter, to give IPTBE also adsorbed on one active site. The apparent activation energy found for both models was estimated to be 71 + 3 kJ mol−1