  Crystallizing zeolites with isotropic properties is critical to the chemical
industry but can be extremely challenging as small deviations in the synthesis
conditions can have extreme effects on the final products. Easily implemented
in-situ monitoring systems could make a real difference, but very few
experimental methodologies cater to the specific needs of applications relying
on harsh, hyper-alkaline conditions involving multiphasic systems such as
Hydrated Silicate Ionic Liquids. Differential impedance spectroscopy (DIS)
promises to enable such studies. It remains highly accurate despite possible
electrode degradation or scaling. This study showcases how in-situ differential
impedance measurements not only enable reliable detection of crystallization of
even minimal amounts of zeolite product but also illustrates how the unique
combination of in situ DIS and in situ, 27Al NMR provides insight into complex,
incongruent zeolite crystallization processes.
