KINETICS OF METHANOL DEHYDRATION ON DEALUMINATED H-MORDENITE - MODEL WITH ACID AND BASIC ACTIVE-CENTERS

The kinetics of methanol dehydration catalysed by dealuminated H-mordenite were studied using a packed bed flow reactor at atmospheric pressure in the 473-573 K temperature range. The data were interpreted in terms of Langmuir-Hinshelwood rate equations and they suggested that two different sites are operative during the dehydration, probably an acid site and its adjacent basic site on which methanol forms respectively [CH3.OH2]+ and [CH3O]- species which, upon condensation, give dimethyl ether and water. Dimethyl ether and/or water compete with the methanol adsorption particularly at lower reaction temperatures and the surface coverages by activated complexes are always large, so that one observes a kinetic order with respect to methanol of less than one.