Thermal activation of ammonium forms of Y zeolites. II. The dehydroxylation process of HNaY zeolites

Abstract

Deammoniated NH 4NaY zeolites have been studied thermodesorptometrically by various methods with respect to the dehydroxylation of the structural OH groups. In each case only one single dehydroxylation peak has been observed, obviously resulting from the intercombination of different kinds of OH groups. Different activation energies obtained for certain ranges of the kinetically evaluated t.p.d, peaks refer to a change of the rate-determining step of dehydroxylation with increasing temperatures. Complete dehydroxylation has not been observed (about one OH group per supercage obviously dehydroxylates only in connection with the framework collapse regardless of the total H + content) as is also shown in the results of catalytic investigations of the but-1-ene isomerization.