AIPO 4-based molecular sieves synthesized in the presence of di- n-propylamine: Are the structures related?

Abstract

Aluminophosphate-based molecular sieves crystallize in the presence of many organic additives. To study the influence of this organic material on the resulting structure, the products of a series of syntheses involving the use of a single organic species, di-n-propylamine (DPA), were investigated. The systematic study of the effect of specific synthesis variables led to the preparation of AIPO4-11 (AEL), VPI-5 (VFI), AIPO4-H3 (APC), MAPO-39, CoAPO-43 (GIS), and MAPSO-46 (AFS). Each sample was characterized by X-ray powder diffraction, scanning electron microscopy (SEM), Guinier-Lenne photographs, and thermogravimetric analysis. SEM did not show any particular pattern of morphological similarity between the samples. A careful examination of the structures revealed that, although the structures are quite different from one another, all have straight channels with at least 8-ring pore openings. Those with one-dimensional channel systems were prepared from gels with a lower DPA:Al2O3 ratio than those with three-dimensional ones. No cages are present in any of the structures synthesized.