Synthesis of zeolite beta Part 2.—Formation of zeolite beta and titanium-beta via an intermediate layer structure

Abstract

The importance of layer structures for the synthesis of zeolite beta is demonstrated. Zeolite beta is formed via a layered-aluminosilicate, which forms spherical agglomerates with diameters in the range 20–50 µm. The transformation into the beta form occurs within the agglomerated particles. The agglomerates are preserved at low temperatures of synthesis. A high intercrystalline volume is created in this way. The conversion of zeolite beta into a layered SiO ₂ (organo-silicate) is observed at low synthesis temperatures and long times of synthesis. The well ordered SiO ₂ structure forms rectangular plates; the XRD patterns are presented. The structure collapses above 473 K with degradation of the template. A weak enrichment of polytype A was observed for some samples crystallized at 368 K. The incorporation of titanium was studied by UV–VIS spectroscopy and by Raman spectroscopic measurements under nearly in situ conditions.