Synthesis and characterization of titanium-aluminophosphate molecular sieves of AFI and AEL topologies

Abstract

Titanium-aluminophosphate molecular sieves (TAPO₄) of AFI and AEL topologies, free of anatase have been synthesised by modified procedure and characterised by XRD, TGA, DTA, Laser-Raman, DRS, FT-IR, ²⁷AI, ³¹P and ¹³C MAS-NMR, SEM and chemical analysis. The synthesised TAPO_4.s are crystalline and pure. The unit-cell constants are found to decrease on substitution of titanium, which occupies tetrahedral position. The chemical analysis and ³¹P MAS-NMR show the presence of traces of P₂O₅ in the channels.