Density, viscosity and speed of sound of binary mixtures of (n-butylammonium acetate + alcohol) at different temperatures and atmospheric pressure
Gustavo V. Olivieri1; Andreia de Araujo Morandin-Giannetti1; Ricardo Belchior Torres1
1 FEI
doi:10.20906/CPS/COB-2015-0481
Resumo
Literature defines ionic liquids (ILs) or room-temperature ionic liquids (RTILs) as organic salts with melting point below 100 oC, resulting from the combination of organic cations and various anions. Ionic liquids are viewed as a novel class of green solvents that attract attention of both industry and academy as substitute for conventional organic solvents. Due to their unique physical and chemical properties they have been used in wide variety of applications including separation and manufacturing processes, in biocatalysis, as lubrificants, as working fluid of electrochemical applications and for processing biomass. Consequently, studies of thermodynamic properties of mixtures involving ionic liquids and organic solvents are gaining importance. In the present work, density, viscosity and speed of sound of the solutions of n-butylammonium acetate + ethanol, ou + 1-propanol have been measured over the entire composition range at (288.15, 293.15, 298.15, and 303.15) K and atmospheric pressure. Both pure liquid and mixture viscosity were measured using a Stabinger viscosimeter (Anton Paar SVM 3000M). Density and speed of sound were measured using a commercial density and speed of sound measurement apparatus (Anton Paar DSA 5000 densimeter and speed of sound analyzer). Excess molar volume, viscosity deviation, isentropic compressibility deviation and excess Gibbs energy of activation have been calculated from the data and fitted to the Redlich-Kister polynomial. For all properties, the values are negative over the entire composition range, except for excess Gibbs energy of activation. Excess molar volume and isentropic compressibility deviation decrease whereas viscosity deviation and excess Gibbs energy of activation increase with increasing in temperature. The results obtained are discussed in terms of intermolecular interactions, particularly hydrogen-bonding interactions between like and unlike molecules.
Palavras-chave: Density; Viscosity; Speed of Sound; Ionic Liquids