Collect. Czech. Chem. Commun. 1992, 57, 946-958

Small Pore AlPO4/SAPO Structures Formed in Dependence on the Silicon Content of the Synthesis Gel

Irina Girnus, Elke Löffler, Ursula Lohse and Frank Neissendorfer

Central Institute of Physical Chemistry, Berlin, D(O)-1199, Germany


The synthesis of small pore AlPO4/SAPO molecular sieves (structures 14, 17, 18, 34) has been investigated at varying silicon content in the gel and with different kinds of templating agents. The samples were characterized by X-ray diffraction, adsorption, thermoanalysis and infrared spectroscopy. Independently of the kind of template at high silicon offer in the gel the crystallization of SAPO-34 is favoured whereas e.g. the formation of SAPO-17 is suppressed. Without silicon, AlPO4-18 is formed instead of AlPO4-34. The nature of template-framework interaction is discussed as a structure-directing factor.