Synthesis of zeolite SSZ-24 using a catalytic amount of SSZ-13 seeds

Abstract

SSZ-24, an AFI-type aluminosilicate, proved to be a zeolite with poor synthesis reproducibility and a slow crystallization rate. The present study deals with the preparation of SSZ-24 by a seed-assisted approach. SSZ-13 and SSZ-24 zeolites are employed as seeds and the impact of the seed content on the formation of SSZ-24 is studied. Both types of zeolites accelerate the zeolite nucleation, shorten the crystallization time, and lead to the formation of pure and highly crystalline SSZ-24. In addition, SSZ-13 seeds are more efficient in terms of rapid crystallization and crystallinity level. Pure and highly crystalline SSZ-24 is readily obtained even though the amount of SSZ-13 seeds was decreased to a “catalytic level”, i.e. 0.3 wt%. The higher seeding power of SSZ-13 seeds is attributed to the presence of framework Al, which stabilizes structural elements that promote the SSZ-24 nucleation.