Influence of water concentration in the viscosities and densities of cellulose dissolving ionic liquids. Correlation of viscosity data

Abstract

The densities and viscosities of aqueous mixtures of two cellulose dissolving ionic liquids: 1-allyl-3-methylimidazolium chloride and 1-ethyl-3-methyl imidazolium acetate ionic liquids have been experimentally determined for water concentration up to approx. 35% water at atmospheric pressure and temperature range from (298.15 to 373.15) K. Molar excess volumes were calculated, resulting in negative values. Literature viscosity correlations were modified in order to describe the viscosity as a function of temperature and water concentration for both water concentrations lower than xH2O = 0.4 and for all the water concentration range. These modified equations were applied to correlate viscosity of (water + ionic liquid) viscosity data for other 1-alkyl-3-methylimidazolium chloride ionic liquids as well as for (ethanol + 1-ethyl-3-methyl imidazolium acetate) from literature obtaining a good reproducibility of the data.