Alkaline Synthesis of Pure Silica ITH Zeolite for Vapor Phase Beckmann Rearrangement of Cyclohexanone Oxime.

Pure silica ITH zeolite is normally synthesized under neutral or acidic conditions in the presence of HF, but it is challenging for synthesis of this zeolite under alkaline conditions. In this work, it is successful for alkaline synthesis of pure silica ITH in the absence of HF using a designed organic template containing F species, showing that the sample obtained has high crystallinity associated with ITH structure, nanosheet morphology, and rich silanol nests. Very importantly, this ITH zeolite exhibited better performance in vapor phase Beckmann rearrangement of cyclohexanone oxime than that of Silicalite-1 zeolite, one of the best catalysts for this reaction.

Atom-Economic Synthesis of Zeolites.

Zeolites are typically synthesized in the presence of strong alkaline or fluoride species, which is not atom-economic for zeolite synthesis due to the high solubility of strong alkaline and fluoride species to silica. One of the solutions for this issue is to reduce solubility of silica in the zeolite synthesis, but it is challenging. Herein, we show that nucleation and growth of zeolites can occur under near neutral conditions, giving an atom-economical synthesis of zeolites with almost full silica utilization due to very low silica solubility.