Intercalation of n-alkylamines by α-zirconium phosphate

Abstract

The intercalation behaviour of α-zirconium phosphate, Zr(HPO₄)₂·H₂O, towards n-alkylamines has been examined. Amines with small carbon chains (C₁–C₄) initially form a phase in which the chain backbone lies parallel to the zirconium phosphate layers. As more amine is intercalated the amines form a bilayer in which the carbon chains incline at roughly 60° to the zirconium phosphate layers. Methyl and propylamine form disordered gels at intermediate levels of intercalation but recrystallize at high levels of amie uptake. The longer-chain amines form a bilayer even at low uptakes. The wet intercalates contain 10–12 mol water per formula weight, mostly as interparticle water rearrangement. On drying to the monohydrates, the interlayer spacings do not change when the solids have a high amine content. At lower amine contents the amine rearranges to yield phases with lower interlayer spacings.