NEW RESEARCH ARTICLE: Determination of Density and Viscosity of Binary Mixtures of Water and Dimethyl Sulfoxide with 1-Ethyl-3-methylimidazolium Diethylphosphate [EtMeIm]+[Et2PO4]− at Atmospheric Pressure

[:en]In the past few years, the global interest in the use of environmentally sustainable resources has increased. Therefore, the biopolymers, and more specifically cellulose, have received most of the attention in the search for new natural, biodegradable, and renewable resources. However, cellulose, due to its complex structure, is not easily processed because it is not soluble in water at room temperature or in other conventional solvents. Some ionic liquids have demonstrated their capacity to dissolve cellulose; however, the solution of cellulose in ionic liquids dramatically increases the viscosity of the mixture. Therefore, cosolvents are frequently added to these mixtures. One of the most common cosolvents is dimethyl sulfoxide (DMSO). This substance is frequently used in cellulose processing with ILs because it decreases the friction between monomers and does not affect cellulose solubility. The recovery of the dissolved cellulose is frequently made using water as an antisolvent. Thus, physical properties of mixtures of water and DMSO with cellulose dissolving ILs are of great interest for the development of the processing of cellulose in ionic liquid media.

It was found that density decreases linearly with temperature while the viscosity decreases exponentially with the same parameter. Excess molar volumes were also calculated. Both systems presented negative excess molar volumes. Nevertheless, while in the mixtures with water an increase in temperature increases the negative excess volume, in the mixtures with DMSO the negative excess molar volume decreases with temperature.

Experimental viscosity data were correlated with modified Grunberg and Nissan correlations, achieving good results.

 

Figure 1. Experimental densities ρ of mixtures of DMSO(2) + [EtMeIm]+[Et2PO4] at 293.15 K, 303.15 K, 313.15 K, 323.15 K, 333.15 K, 343.15 K, 353.15 K, 363.15 K and 373.15 K as a function of DMSO mole fraction x2.

The whole work can be found at: https://doi.org/10.1021/acs.jced.7b00788[:es]In the past few years, the global interest in the use of environmentally sustainable resources has increased. Therefore, the biopolymers, and more specifically cellulose, have received most of the attention in the search for new natural, biodegradable, and renewable resources. However, cellulose, due to its complex structure, is not easily processed because it is not soluble in water at room temperature or in other conventional solvents. Some ionic liquids have demonstrated their capacity to dissolve cellulose; however, the solution of cellulose in ionic liquids dramatically increases the viscosity of the mixture. Therefore, cosolvents are frequently added to these mixtures. One of the most common cosolvents is dimethyl sulfoxide (DMSO). This substance is frequently used in cellulose processing with ILs because it decreases the friction between monomers and does not affect cellulose solubility. The recovery of the dissolved cellulose is frequently made using water as an antisolvent. Thus, physical properties of mixtures of water and DMSO with cellulose dissolving ILs are of great interest for the development of the processing of cellulose in ionic liquid media.

It was found that density decreases linearly with temperature while the viscosity decreases exponentially with the same parameter. Excess molar volumes were also calculated. Both systems presented negative excess molar volumes. Nevertheless, while in the mixtures with water an increase in temperature increases the negative excess volume, in the mixtures with DMSO the negative excess molar volume decreases with temperature.

Experimental viscosity data were correlated with modified Grunberg and Nissan correlations, achieving good results.

Figure 1. Experimental densities ρ of mixtures of DMSO(2) + [EtMeIm]+[Et2PO4] at 293.15 K, 303.15 K, 313.15 K, 323.15 K, 333.15 K, 343.15 K, 353.15 K, 363.15 K and 373.15 K as a function of DMSO mole fraction x2.

 

The whole work can be found at: https://doi.org/10.1021/acs.jced.7b00788[:]

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