Fast synthesis of hierarchical Beta zeolites with uniform nanocrystals from layered silicate precursor

Abstract

Hierarchical Beta zeolite composed of uniform nanocrystals with high pore volume and external surface area was fast synthesized within 4 h at a high yield using layered silicate precursor (H-kanemite) as silica source. The transformation process of layered silicate precursor into Beta zeolite is investigated carefully by XRD, FT-IR, NMR spectroscopies, SEM, and TEM techniques. TEM and SEM images indicated the obtained Beta zeolite is consisted of self-sustaining macrosized zeolitic aggregates assembled from uniform nanosized crystals, and it possesses relatively narrow distributed intercrystal mesopores. The hierarchically structured Beta zeolite, with an enhanced accessibility for bulky molecule to acid sites in the framework, shows better catalytic behaviors in the industrially-relevant Friedel-Crafts acylation reaction in comparison to commercially available or traditional Beta zeolite.