N-Methyl-2-pyrrolidone-promoted crystallization of MEL zeolite and its acceleration mechanism

Abstract

ZSM-11 zeolite is an important microporous material that has wide application prospects in various petrochemical and chemical processes. Herein, we reported a simple method to significantly reduce the crystallization time of ZSM-11 zeolite by adding N-methyl-2-pyrrolidone (NMP) as the ‘promoter’. The effects of various synthetic parameters on the NMP-assisted synthesis of ZSM-11 zeolite were also investigated. Subsequently, characterization techniques such as SEM, XRD, XRF, FT-IR, TEM-EDS, TG and ¹³C NMR were used to unveil the acceleration mechanism of NMP. It was revealed that NMP can facilitate the bonding of TBA⁺ with aluminosilicate by breaking the hydration layer around them, thus reducing the apparent nucleation activation energy and accelerating the nucleation process. Meanwhile, we used N-ethyl-2-pyrrolidone (NEP) instead of NMP as the promoter to verify the acceleration mechanism. In addition, the fast-synthesized ZSM-11 zeolite exhibited comparable composition, hydrothermal stability, and catalytic performance to conventionally synthesized counterparts.