Interzeolite transformation
has been used to produce a novel family
of hierarchical catalysts featuring excellent textural properties,
strong acidity, and superior catalytic performance for the Friedel–Crafts
alkylation of indole with benzhydrol, the Claisen–Schmidt condensation
of benzaldehyde and hydroxyacetophenone, and the cracking of
polystyrene. Intermediate solids of the FAU interzeolite transformation
into BEA display both increased accessibility—due to the development
of mesoporosity—and strong acidity—caused by the presence
of ultrasmall crystals or zeolitic fragments in their structure. The
use of surfactants allows for the development of the hierarchical
catalysts with very narrow pore size distribution. The properties
of interzeolite transformation intermediates (ITIs) can be fine-tuned
simply by stopping the interconversion at different times.