Selective Crystallization of Highly Dispersed Silicoaluminophosphate SAPO-11

Abstract

The authors have proposed a method for selective crystallization of a high dispersion SAPO-11 silicoaluminophosphate molecular sieve. X-ray diffraction analysis, low-temperature nitrogen adsorption and scanning electron microscopy were used to determine the chemical and phase compositions, characteristics of the porous structure, and the morphology of SAPO-11. It has been shown that crystallization of a silicoaluminophosphate gel prepared using pseudoboehmite as a source of aluminum and aged at 90 0 C allows obtaining the above zeolite of high phase purity and a degree of crystallinity equal to 96%. According to the data of scanning electron microscopy, the obtained SAPO-11 samples are characterized by a morphology close to cubic and a crystal size from 0.2 to 0.5 µm.