Abstract

The AlPO₄-5 molecular sieve is successfully synthesized using the gel composition (C₂H₅)₃N∶Al₂O₃∶P₂O₅∶xH₂O. It is shown that the water content in the starting molar gel composition plays a dominant role in the synthsis of AlPO₄-5. When the water content is low, the conversion of reagents to AlPO₄-5 is nearly complete and the synthesized products have better crystallisation, higher crystallinity and the ideal Al/P ratio. SEM also reveals that there is a preference for the formation of thin hexagonal platelets in AlPO₄-5 samples synthesized from starting molar gel compositions with 10 or 20 H₂O. Reducing the water content in the molar gel composition also results in a longer shelf life for AlPO₄-5. Similar structures and thermal behaviour of all of the synthesized samples are also observed in their XRD, FTIR and TGA analysis.