Organic-free synthesis, structure and properties of multicomponent ZSM-5 type zeolites

Abstract

The SiO₂/Al₂O₃ molar ratio, acidity and particle size of ZSM-5 synthesized in the absence of organic additives can be regulated simultaneously by the addition of various inorganic compounds to the synthesis mixture. The combined addition of chromium and boron leads to products in which the properties of the single systems, e.g. small zeolite particles in the chromium-containing samples and reduced acidity in the boron-containing zeolites, are reflected in a catalytically advantageous manner. This is demonstrated by the results from acid- or bifunctionally catalysed hydrocarbon conversion reactions: paraffin cracking, xylene isomerization and dehydrocyclization.