Preparation of Aluminium Phosphate with a Layered Structure by Using Organic Solvent and Its Properties
Kiyoko Sakamoto, ShunroYamaguchi and Atsushi Nakahira
Abstract:We have synthesized the pure single phase of aluminium tri-hydrogen bis (orthophosphate) monohydrate [AlH3(PO4)2 EH2O] by using hydrophilic organic solvent, with high efficiency. It is a material with layered structure. The optimum condition to prepare it was as follows ; the mixtures of 75 wt% H3PO4@and Al(OH)‚R@(0.1 mol) (molar ratio of H3PO4 to Al(OH)‚R = 4.0 ) was refluxed at 94Ž for 6 hours under stirring in 1-propanol (200 cm3). Shape of products obtained was needle, and its length increased from 5 ƒÊm to 80 ƒÊm with increasing the reaction times. The maximal acid strength and amount of acid of solid surface were pKa = +1.5 and 1.81`2.13 (x10-2 mmol g-1), respectively. AlH3(PO4)2 EH2O changed to AlPO4 (berlinite, cristobalite-form) and Al(H2PO4)3 (B-form, C-form) by dehydration of monohydrate at 160Ž. Key Words:Aluminium phosphate, Aluminium tri-hydrogen bis (orthophosphate) monohydrate, Layered structure, Hydrophilic organic solvent