Synthesis of hierarchical Beta zeolite with uniform mesopores: Effect on its catalytic activity for veratrole acylation

摘要

Uniform mesoporosity has been effectively developed in hierarchical Beta zeolite by means of a hydrothermal treatment at 110 degrees C with an ammonia/surfactant solution. As a result, the broad pore size distribution, existing within the supermicropore-mesopore range in the parent hierarchical Beta sample, was rearranged into a uniform one centred at 40 A. In contrast, this treatment was less effective when applied to a conventional Beta zeolite sample with little secondary porosity. Neither amorphous phases nor MCM-41-like materials were detected after the mesopore narrowing treatment. Likewise, FTIR/pyridine measurements of the zeolite samples indicated that their acid properties were preserved after the ammonia/surfactant treatment, while just small variations were observed in the Si/Al ratio.