A PROCESS FOR SYNTHESIZING SAPO-34 MOLECULAR SIEVE ENRICHED WITH Si(4Al) COORDINATION STRUCTURE IN THE FRAMEWORK

摘要

Provided is a process for synthesizing SAPO-34 molecular sieve enriched with a Si(4Al) coordination structure, the molecular sieve synthesized by the process predominately has Si(4Al) structure in Si coordination environment of the molecular sieve frame. The process utilizes post-modifying technology to selectively remove Si from the framework of the synthesized SAPO molecular sieve, such that the content of Si(0Al), Si(1Al), Si(2Al) and Si(3Al) in the molecular sieve framework is reduced or eliminated, thereby increasing the relative content of Si(4Al) in the coordination environment. The SAPO-34 molecular sieve enriched with a Si(4Al) structure is used as MTO or DTO catalyst after being baked and could improve the selectivity of ethene.