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 dehydrogenation-dehydration of 2-propanol was studied by using a tubular flow reactor. The oxides were synthesized from different precursors by using various methods. The influence of the precursor used, in vacuo calcination 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 constants of dehydrogenation and dehydration obtained for the test reaction were 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 isothermal reaction, which were detected by temperature-programmed desorption, were found to be the two primary sources. Finally, the reaction mechanism was studied; the two proposed pathways are consistent with the results obtained. (C) 1996 Academic Press, Inc.