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.