Syntheses of chromium(III)-doped aluminophosphate-5 molecular sieves from various gels

The crystallization fields of Cr(III)-doped AlPO4-5 have been investigated by hydrothermally treating gels with various compositions at 170°C for 24h. From the results it was found that the AFI structure was more easily prepared from the starting gel with a small amount of Cr(III) ions than that without Cr(III) ions, and tri-n-propylamine was useful as a template for the synthesis of Cr(III)-doped AlPO4-5 with good crystallinity (i.e., light green hexagonal prisms along the c-axis). Furthermore, the synthesis condition to produce excellent, large, Cr(III)-doped AlPO4-5 crystals up to 0.3mm in length was successfully discovered.