CONVERSION OF ALCOHOLS (ALPHA-METHYLATED SERIES) ON ALPO4 CATALYSTS

The conversion (dehydration/dehydrogenation) of alcohols in alpha-meth ylated series (methanol, ethanol, 2-propanol, and tert-butanol) on AlP O4 catalysts differently prepared has been studied by microcatalytic p ulse reactor technique at different temperatures and flow rates. The k inetic parameters have been obtained by analysis of the data through t he Bassett-Habgood equation. Dehydration to ether and/or olefin is the major reaction process. Dehydrogenation product was only scarcely fou nd in 2-propanol conversion. The influence of the reaction temperature upon the conversion of alcohols and the selectivities of the products was investigated. Activity increases as a function of surface acidity of the AlPO4 catalyst as well as with the a-substitution in the alcoh ol. Moreover, selectivity studies indicated that ethanol and 2-propano l dehydration follows a combination pathway of parallel and consecutiv e reactions. A good correlation between the results of dehydration con version and acid properties, gas-chromategraphically measured through the irreversible adsorption of pyridine (473 and 573 K) and 2,6-dineth ylpyridine (573 K), is observed. Also, activity poisoning results indi cated that Bronsted acid sites of AlPO4 catalyst participated in dehyd ration processes, thus strengthening the carbenium ion reaction pathwa y in AlPO4 catalysts. (C) 1995 Academic Press, Inc.