Effect of synthesis medium and synthesis conditions on physicochemical properties of hierarchical SAPO-11 molecular sieve synthesized via fractional crystallization method

Graphical The effects of synthesis medium and synthesis conditions on the physicochemical properties of SAPO-11 molecular sieve were explored by combining the hydrothermal crystallization method with the fractional crystallization method. SAPO-11 molecular sieve has been widely used as the support of bifunctional catalyst for hydroisomerization of n-alkanes because of its mild acidity and unique one-dimensional pore structure, and has been widely used in industry. However, how to further improve and improve the physicochemical properties of SAPO-11 molecular sieve is still worth studying. In this work, fractional crystallization method was used to synthesize graded SAPO-11 molecular sieve. The effects of medium system, feed SiO 2 /Al 2 O 3 , crystallization time and crystallization temperature of the second crystallization process on the physicochemical properties of SAPO-11 molecular sieve were investigated from the perspectives of crystallinity, textural properties and acidity. The suitable synthesis medium and the best synthesis conditions were determined. It is expected to provide reference for the fractional crystallization synthesis of high performance SAPO-11 molecular sieve.