Preparation of hierarchical SSZ-13 by NH4F etching

NH4-SSZ-13 is etched with an aqueous solution of 40 w/% NH4F under different time/temperature conditions to obtain hierarchical derivatives. The etched zeolites are characterized by XRD, SEM, N-2 physisorption, Si-29/Al-27/F-19 MAS NMR, ICP-AES, and their acidity monitored by in situ FTIR spectroscopy using acetonitrile as a probe molecule. The results highlight that the zeolite is very sensitive to high temperature and high liquid-solid ratio treatments leading to substantial crystallinity losses. These two parameters need careful tuning to obtain hierarchical derivatives retaining important characteristics as micropore volume and framework Si/Al ratio. The catalytic activity of the modified SSZ-13 is evaluated in the n-propanol conversion.

Automated summary

NH4-SSZ-13 zeolite is etched using an aqueous solution of 40% NH4F under different time/temperature conditions to obtain hierarchical derivatives. The zeolites exhibit sensitivity to high temperature and high liquid-solid ratio treatments, which can lead to significant crystallinity losses. Careful tuning of these parameters is necessary to retain important characteristics in the hierarchical derivatives. The catalytic activity of the modified SSZ-13 is evaluated in n-propanol conversion.