Seed‐Assisted Synthesis of MWW‐Type Zeolite with Organic Structure‐Directing Agent‐Free Na‐Aluminosilicate Gel System

The seed‐assisted synthesis of zeolites without using organic structure‐directing agents (OSDAs) has enabled alternative routes to the simple, environmentally friendly and low‐cost production of industrially important zeolites. In this study, the successful seed‐assisted synthesis of MCM‐22 (MWW‐type) zeolite with an OSDA‐free gel is reported for the first time. MWW‐type zeolites are obtained by the addition of as‐synthesized MCM‐22 seeds prepared with hexamethyleneimine (HMI) into OSDA‐free Na‐aluminosilicate gels. Based on the results of XRD, ICP‐AES, NMR, N₂ physisorption and NH₃‐TPD, the product exhibited different features compared to those of the seeds. The H‐form product can serve as a catalyst in Friedel–Crafts alkylation reaction of anisole with 1‐phenylethanol, and its catalytic activity is comparable to the seeds. Furthermore, XRD, FE‐SEM, TG‐DTA, CHN, FT‐IR and NMR analyses of products and intermediates provide insights into the role of seeds and occluded HMI, the crystallization process, and key factors for achieving seed‐assisted synthesis of MWW‐type zeolites with an OSDA‐free gel system. The present results provide a new perspective for the economical and environmentally friendly production of MWW‐type zeolites.