抄録
The heats of ion exchange for alkaline metal ions and those of intercalation for n-alkylamines into a-zirconium phosphate (α-ZrP) have been measured in aqueous solution and ethanol solvent by a twin conduction type microcalorimeter. It was found that the ion exchange for alkaline metal ions and intercalation of n-alkylamines in α-ZrP were exothermic reaction assisted with neutralization effect as driving force. The heats of them decreased with increasing in initial concentrations of the guest alkaline ions and n-alkylamines. Taking the results from the XRD before and after the ion-exchange reaction of α-ZrP into account, hydrated Li+ ions in aqueous solution were considered to be exchanged for protons (H+) in interlayer of α-ZrP with almost perfectly dehydrated states, while Na+ ions were exchanged in partially hydrated state. These phenomena were explained to be due to the estimated larger positive entropy changes (ΔS) by the dehydration effect for the Li+ ion exchange than those of the Na+ ion exchange reaction.
The order of the exothermal intercalation heats of n-alkylamines in aqueous solution was C3> C4> C6 > C8, while that in ethanol solution was C8 > C6 > C4> C3. The reverse result was estimated to be due to the difference of basicity strength of the amines by induction minus effect (-I effect) of the alkyl groups in aqueous and ethanol solution.
