title: Thermophysical properties of two ammonium-based protic ionic liquids.
abstract: Experimental data for density, viscosity, refractive index and surface tension are reported, for the first time, in the temperature range between 288.15 K and 353.15 K and at atmospheric pressure for two protic ionic liquids, namely 2-(dimethylamino)-N,N-dimethylethan-1-ammonium acetate, [N11{2(N11)}H][CH3CO2], and N-ethyl-N,N-dimethylammonium phenylacetate, [N112H][C7H7CO2]. The effect of the anion aromaticity and the cation's aliphatic tails on the studied properties is discussed. From the measured properties temperature dependency the derived properties, such as the isobaric thermal expansion coefficient, the surface entropy and enthalpy, and the critical temperature, were estimated.
authors.affiliation: CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Arijit
authors.initials: A
authors.lastname: Bhattacharjee
authors.affiliation: CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: João A P
authors.initials: JA
authors.lastname: Coutinho
authors.affiliation: CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Mara G
authors.initials: MG
authors.lastname: Freire
authors.affiliation: CICECO, Departamento de Química, Universidade de Aveiro, 3810-193 Aveiro, Portugal.
authors.forename: Pedro J
authors.initials: PJ
authors.lastname: Carvalho
keywords: Density; Protic ionic liquids; Refractive index; Surface tension; Viscosity