日本ゼオライト学会　刊行物 Publication of Japan Zeolite Association

Various methods for zeolite synthesis have been developed, among which hydrothermal synthesis using organic molecules as structure-directing agents (SDAs) has become the mainstream approach. Zeolite synthesis using SDAs offers the advantage of producing large pores; however, the crystallization pathway remains unclear due to the involvement of hydrothermal conditions. Consequently, the design of zeolites with arbitrary framework structures and functionalities has not yet been achieved. To overcome this issue, synthesis processes that employ layered silicates and two-dimensional (2D) zeolites as starting materials have been developed as a new approach to allow for precise control of the framework structure. This approach has enabled the synthesis of zeolites with novel framework structures, as well as those that cannot be obtained under conventional hydrothermal conditions, hereby significantly broadening the scope of zeolite design. In this paper, we introduce a novel zeolite synthesis method based on the assembly of composite building unit (CBU), as a strategy for achieving controlled framework structures. Using a hydrogen-bonded inorganic framework as a pre-organized CBU, a novel zeolite was prepared via dehydrative condensation reactions under acid condition. Crystallization occurred throughout this process while the CBU structure was maintained, leading to a novel zeolite with an eight-membered ring.