C. Fite et al., KINETICS OF THE LIQUID-PHASE SYNTHESIS OF ETHYL TERT-BUTYL ETHER (ETBE), Industrial & engineering chemistry research, 33(3), 1994, pp. 581-591
The liquid-phase addition of ethanol to isobutene to give ethyl tert-b
utyl ether (ETBE) on the ion exchange resin Lewatit K2631 has been stu
died. Rate data were obtained free of mass transfer influence in a con
tinuous differential reactor operated at 1.6 MPa and 40-90-degrees-C,
measuring steady-state conversions <10% for ethanol-isobutene and etha
nol-isobutene-ETBE feeds. The reaction is highly temperature-sensitive
. Isobutene has an enhancing effect on the rate whereas ethanol has an
inhibitor one. Besides, low ETBE concentrations enhance the reaction
but as chemical equilibrium is approached the ether shows an inhibitor
effect, as expected. As alcohol-olefin-ether mixtures behave nonideal
ly, kinetic analysis has been performed by using the UNIFAC liquid-pha
se activities of isobutene, ethanol, and ETBE. The best kinetic model
stems from an Eley-Rideal mechanism in which the ethanol, adsorbed on
one center, reacts with the isobutene from solution to give the ether
adsorbed on one center. Surface reaction is the rate-limiting step. Tw
o additional centers take part in this step.