Synthesis and Characterization of SAPO-37 Molecular Sieve

Abstract

Several synthesis parameters including silica precursor, alumina precursor and composition of reactant gel, during hydrothermal synthesis of SAPO-37, were studied. It was found that silica species is one indispensable component for the formation of SAPO-37. SAPO-37 could be synthesized only in a very narrow range within weak basic condition of pH = 8 ~ 9. In the use of no silica starting gel even SAPO-37 seeding, AlPO4-5 and SAPO-5 dominated the zeolite product without SAPO-37 formation. A new ion exchange procedure was developed for the removal of tetrapropyl ammonium (TPA) template from SAPO-37 with enhanced thermal stability by which the structure damage in SAPO-37 caused by the excessive steam during TPA burning could be avoided.