Physicochemical properties of {1-methyl piperazine (1) + water (2)} system at T = (298.15 to 343.15) K and atmospheric pressure

Abstract

Densities ( ρ) and viscosities ( η) of aqueous 1-methylpiperazine (1-MPZ) solutions are reported at T = (298.15 to 343.15) K. Refractive indices ( n D ) are reported at T = (293.15 to 333.15) K, and surface tensions ( γ) are reported at T = (298.15 to 333.15) K. Derived excess properties, except excess viscosities (Δ η), are found to be negative over the entire composition range. The addition of 1-MPZ reduces drastically the surface tension of water. The temperature dependence of surface tensions is explained in terms of surface entropy ( S S ) and enthalpy ( H S ). The measured and derived properties are used to probe the microscopic liquid structure of the bulk and surface of the aqueous amine solutions.