NOVEL ALUMINOPHOSPHATE-BASED COMPOUNDS WITH A LAYERED STRUCTURE AND INTERCALATION BEHAVIOR

A novel group of aluminophosphates with the formula R3/2[Al3H3(PO4)4] where R represents a long-chain diamine H2N(CH2)(n)NH2 with n greater-than-or-equal-to 8 is described. In these aluminophosphates, referred to as SCS-22, aluminium and phosphorus are tetrahedrally coordinated. Isomorphous substitution, e.g. of Co for Al and Si for P, is possible as in the case of three-dimensional aluminophosphate molecular sieves. However, SCS-22 compounds exhibit a layered structure. It appears that the P-OH groups at the sheet surfaces interact with the amine groups of a monolayer of intercalating diamines. A linear relationship has been established between the chain length of the diamine and the interlayer distance, indicating that the diamine molecules are inclined at an angle of ca. 60-degrees with respect to the aluminophosphate sheets.