HSIL-Based Synthesis of Ultracrystalline K,Na-JBW, a Zeolite Exhibiting Exceptional Framework Ordering and Flexibility

A reproducible synthesis
strategy for ultracrystalline K,Na-aluminosilicate
JBW zeolite is reported. The synthesis uses a Na-based hydrated silicate
ionic liquid (HSIL) as a silicon source and gibbsite as the aluminum
source. 27Al and 23Na NMR spectra exhibit crystalline
second-order quadrupole patterns in the hydrated as well as dehydrated
states and distinct resonances for different T-sites demonstrating
an exceptional degree of order of the elements of the JBW framework,
observed for the first time in a zeolite. Detailed structural analysis
via NMR crystallography, combining powder X-ray diffraction and solid-state
NMR of all elements (27Al, 29Si, 23Na, 39K, and 1H), reveals remarkable de- and
rehydration behavior of the JBW framework, transforming from its as-made
hydrated structure via a modified anhydrous state into a different
rehydrated symmetry while showing astonishing flexibility for a semicondensed
aluminosilicate. Its crystallinity, exceptional degree of ordering
of the T atoms and sodium cations, and the fully documented structure
qualify this defect-free K,Na-aluminosilicate JBW zeolite as a suitable
model system for developing NMR modeling methods.