Dielectric Relaxation of Water in Aqueous Solutions of n‐Alkylamine Hydrochlorides Part 1: Solute Concentrations Smaller than the Critical Micelle Concentrations

Abstract

AbstractThe solutes are the homologous salts CH3(CH2)nNH3Cl with n = 3, 5, 6, and 7. The complex permittivity of the solutions has been measured in dependence of frequency between 5 and 37 GHz at 25°C.From the analysis of the frequency dependence of the complex permittivity, statements are made on the orientational polarizability, the reorientation time and the number of the hydration water molecules of the n‐alkylammonium ions. The orientational polarizability of the hydration water does not markedly differ from that of pure water. The reorientation time and the numbers of the disturbed water molecules around the cations strongly increase with increasing hydrocarbon chain length of the cations.The reorientation times and the numbers of the hydration water molecules of the n‐alkylammonium ions are compared with those of the tetra‐alkylammonium ions. From this comparison is clearly established that the hydrophobic interaction around the former ions is more pronounced than around the latter.