Charge distribution and conformational stability effects of organic structure-directing agents on zeolite synthesis

While the use of the so-called organic structure-directing agents (OSDAs) is no stranger to zeolite synthesis at all, the effects of their charge distribution and conformational stability on the phase selectivity of the crystallization remain elusive. To systematically investigate these effects, we have prepared a series of imidazolium and pyrazolium derivatives with the same geometric shape but different positions of nitrogen atoms in the five-membered heterocyclic aromatic ring and used them as OSDAs for the synthesis of zeolites with pure-silica composition. Meaningful differences in the zeolite product were observed.