Aggregation of dodecyldimethylamine N-oxide perchlorate in benzene

Abstract

Osmotic coefficients measured by vapour pressure osmometry are reported for solutions of dodecyldimethylamine N-oxide perchlorate over the concentration range 0.008–0.38 mol kg^–1 at 27, 33, 40, and 50 °C. Solute activities decrease rapidly with increasing concentration owing to dipole–dipole association. The non-ideal behaviour of the system is interpreted in terms of an association model, which includes an extended series of multimers, and the association equilibrium constant, enthalpy (ΔH°=–3.34 kcal mol^–1) and entropy (ΔS°=–10.34 cal mol^–1 K^–1) are derived.