APPLICATION OF THE RESPONSE-SURFACE METHODOLOGY TO THE KINETIC-STUDY OF THE GAS-PHASE ADDITION OF ETHANOL TO ISOBUTENE ON A SULFONATED STYRENE DIVINYLBENZENE RESIN

The kinetics of vapor-phase addition of ethanol to isobutene to give ethyl tert-butyl ether (ETBE) on the ion exchange resin Amberlyst 15 has been studied. Rate data were obtained in a continuous differential reactor operated at atmospheric pressure and 53-78.5-degrees-C. The most probable Langmuir-Hinshelwood-Hougen-Watson (LHHW) rate models stem from two quite similar reaction mechanisms. Four active centers take part in the rate-determining step of the two mechanisms. The first one suggests the reaction between the ethanol and the isobutene, both adsorbed molecularly on one center, and the second mechanism proposes the reaction between the ethanol adsorbed molecularly on one center and the isobutene adsorbed on two centers without cleavage. Both mechanisms are physicochemically coherent.