MAGNESIUM OXIDES AS BASIC CATALYSTS FOR ORGANIC PROCESSES STUDY OF THE DEHYDROGENATION-DEHYDRATION OF 2-PROPANOL

The reactivity of various magnesium oxides in the gas-phase dehydrogen ation-dehydration of 2-propanol was studied by using a tubular flow re actor. The oxides were synthesized from different precursors by using various methods. The influence of the precursor used, in vacuo calcina tion and B2O3 doping was analyzed in the light of the results obtained in the above-mentioned test reaction. Potential correlations between the surface acid-base properties of the oxides and the kinetic constan ts of dehydrogenation and dehydration obtained for the test reaction w ere sought. Also, potential sources of deactivation for the catalysts were investigated. Carbon deposits observed by temperature-programmed oxidation and the presence of strongly adsorbed species following an i sothermal reaction, which were detected by temperature-programmed deso rption, were found to be the two primary sources. Finally, the reactio n mechanism was studied; the two proposed pathways are consistent with the results obtained. (C) 1996 Academic Press, Inc.