Synthesis and Characterization of a Family of Amine-Intercatalated Lamellar Aluminophosphates from Alcoholic System

A family of lamellar aluminophosphates designated APO-L n (L stands for lamellar and n = 6, 8, 10, 12, the number of carbon atoms for the occluded template molecules) was synthesized from a mixture of phosphoric acid, aluminum triisopropoxide, ethylene glycol and an unbranched primary alcohol in the presence of an amine as the structure-directing template. The compounds were characterized by X-ray powder diffraction, scanning electron microscopy, MAS NMR spectroscopy, differential thermal, and thermogravimetric analyses. The inorganic layers of APO-L n are composed of PO 4, AlO 4, and AlO 6 structural units, and the ratio of the octahedral Al to the tetrahedral Al in the as-synthesized compounds is about 1:1. APO-L n exhibit a distinct weight loss when treated at elevated temperatures, and upon dehydration they adsorb a considerable amount of water. Dehydration−rehydration for APO-L n materials is reversible with the dehydrated samples containing almost only tetrahedrally coordinated aluminum.