In the present work, an Eyring-theory model based on concepts of excess Gibbs energy of activation of the viscous flow has been developed for the accurate correlation or prediction of the dynamic viscosity of ionic solutions: inorganic salt (electrolyte) + solvent and organic salt (ionic liquid) + solvent. For the excess Gibbs energy of activation (G EX,≠ ), both thermal and mechanical contributions to the viscous flow were considered. Accordingly, a thermal G EX,≠ term was described by mixing rules of the Redlich−Kister-type, whereas the mechanical G EX,≠ term was computed from a simple cubic equation of state in an attempt to overall represent the main molecular interactions (between the ionic species and the solvent) affecting viscosity. The resulting model was successfully validated during the representation of experimental dynamic viscosities of various nonaqueous and aqueous ionic solutions within wide ranges of temperature and composition (or salt molality). ■ INTRODUCTIONIn general, ionic solutions comprise those liquid mixtures containing either inorganic or organic ionic species plus a solvent that could be water or an organic compound. The viscosity of ionic solutions plays a very important role in a number of geophysical and engineering applications; its precise knowledge is therefore paramount. Some examples of these applications include the transport of geothermal fluids through wells and ducts, the modeling of geothermal reservoirs, the design of both mass-and heat-transfer equipment, and the simulation of petroleum reservoirs, among others.A significant amount of experimental data have been published in the literature dealing with the dynamic viscosity of binary ionic solutions containing either strong or weak electrolytes, mostly at atmospheric pressure and aqueous conditions. 1,2 On the other hand, during the last 12 years, a number of experimental works have increasingly appeared regarding viscosity measurements of aqueous and nonaqueous ionic solutions containing ionic liquids (ILs). 3−10 Unlike inorganic salts, ILs belong to a particular class of organic salts that behave as liquids below 100°C. They usually comprise a large organic cation in combination with an organic or inorganic anion of smaller size. The various combinations of cations and anions conveniently allow tailoring IL properties for specific engineering applications.As far as viscosity models for ionic solutions are concerned, many modeling efforts have been reported in the literature regarding the viscosity of electrolyte solutions. Most of these models are essentially empirical or semiempirical in nature and apply to aqueous and mixed-solvent electrolyte systems. 11−18 As a matter of fact, Laliberté1 6 published a comprehensive review on the available approaches for modeling the viscosity of electrolyte solutions. In general, these modeling efforts range from simple viscosity correlations that are only applicable to single solutes in dilute solutions (e.g., the Jones−Dole equation 19 ) to more comprehensive models that are n...

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In this study, simultaneous experimental measurements of dynamic viscosity and density of four Newtonian liquids (undecane, dodecane, tridecane, and tetradecane) were performed in the pressure range from 1.99 to 50.01 MPa, along five isotherms between 298.15 and 353.16 K. The dynamic viscosity and density were determined using the capillary flow technique and a vibrating tube densimeter, respectively. The viability of the methods used was verified through the experimental measurements of the viscosity and density of ethanol and its comparison with data published in the international literature, resulting a maximum deviation of 1.25% for viscosity and 0.58% for density. The relative combined expanded uncertainty (k = 2) for the experimental measurements was estimated to be 1.4% and 0.2% for dynamic viscosity and density data, respectively, considering the impurities of the chemical compounds. Also, two empirical models were used to represent the experimental data reported in this work; for the dynamic viscosity, a maximum deviation of 0.5% was found, while, for density, a maximum deviation of 0.11% was obtained. From density data and using the empirical model, the isothermal compressibility and isobaric thermal expansivity were evaluated under the reported conditions.