Vermiculite-aliphatic amine interactions at the solid/liquid interface: a thermodynamic approach

Polar n -alkylmonoamines of general formula H 3 C(CH 2 ) n NH 2 ( n = 1, 3, 5) interacted with layered silicate vermiculite at the solid/liquid interface. The maximum amount of amine intercalated ( N f ) inside the interlamellar space were 0.62, 0.46, and 0.38 mmol g −1 , to give the following order of intercalation ethyl → butyl → hexylamines. The layered vermiculite solid was suspended in deionized water and calorimetrically titrated with this series of amines, to give favorable thermodynamic data, such as exothermic enthalpy, negative Gibbs free energy and positive entropy data.