Intermediate Phases in Synthesis of AlPO4-5 Molecular Sieve: A Study of XRD and Raman Spectroscopy

We study the intermediate phases and their evolution during crystallization of Aluminophosphate molecular sieves. In this work, the behaviors of the initial gel and the evolution of the intermediate phases during crystallization of AlPO₄-5 molecular sieve using triethylamine as a template have been investigated. It has been shown that in the amorphous aluminophosphate gel phases, template triethylamine does exist in protonated form; and there appear a significant change, formation of 12-member rings of AlPO₄-5 structure, during the early stage of crystallization of AlPO₄-5. In addition, a proposition to explain the crystallization of AlPO₄-5 is also suggested.