A simple and generalized model for predicting the density of ionic liquids

Abstract A simple and accurate model to predict the density of ionic liquids is presented. The proposed model is based on a generalized correlation that has been conveniently modified and experimental literature data have been used to fit the five model parameters, to finally propose an equation that allows predicting densities of any ionic liquid. The model uses the critical temperature, the critical volume, the normal boiling temperature and the molecular mass to estimate the density at temperatures commonly used in ionic liquid applications (270–360 K). A set of 602 density data for 146 ionic liquids has been used in the study. The results were compared with predictions of ten generalized corresponding states principle correlations available in the literature. These generalized correlations have not been applied to ionic liquids before so the appropriateness and accuracy of these models to ionic liquid density estimation are unknown until now. Results show that the new simple correlation gives low deviations and can be used with confidence in thermodynamic and engineering calculations.

[1]  Xuezhong He,et al.  Physical Properties of Ionic Liquids: Database and Evaluation , 2006 .

[2]  E. Goharshadi,et al.  Thermodynamic properties of some ionic liquids using a simple equation of state , 2008 .

[3]  J. Valderrama,et al.  Reply to “Comment on ‘Critical Properties, Normal Boiling Temperature, and Acentric Factor of Fifty Ionic Liquids'” , 2007 .

[4]  José O. Valderrama,et al.  The state of the cubic equations of state , 2003 .

[5]  O. Hougen,et al.  Generalized thermodynamic properties of pure fluids , 1955 .

[6]  V. Bhirud.  Saturated liquid densities of normal fluids , 1978 .

[7]  R. Smith,et al.  Pressure–volume–temperature (PVT) measurements of ionic liquids ([bmim+][PF6−], [bmim+][BF4−], [bmim+][OcSO4−]) and analysis with the Sanchez–Lacombe equation of state , 2008 .

[8]  M. Shiflett,et al.  Solubility and Diffusivity of Difluoromethane in Room-Temperature Ionic Liquids , 2006 .

[9]  J. Valderrama,et al.  Generalized rackett-type correlations to predict the density of saturated liquids and petroleum fractions , 1989 .

[10]  R. Reid,et al.  The Properties of Gases and Liquids , 1977 .

[11]  Juan A. Lazzús,et al.  Critical Properties, Normal Boiling Temperature, and Acentric Factor of Another 200 Ionic Liquids , 2008 .

[12]  Peter Wasserscheid,et al.  Ionic Liquids in Synthesis , 2002 .

[13]  Liquid Saturation Density from Predictive Correlations Based on the Corresponding States Principle. Part 1: Results for 30 Families of Fluids , 2006 .

[14]  J. Valderrama,et al.  Critical Properties, Normal Boiling Temperatures, and Acentric Factors of Fifty Ionic Liquids , 2007 .

[15]  J. Valderrama,et al.  Liquid Volumes from Generalized Cubic Equations of State: Take It with Care , 2000 .

[16]  C. Ye,et al.  Rapid and accurate estimation of densities of room-temperature ionic liquids and salts. , 2007, The journal of physical chemistry. A.

[17]  R. D. Gunn,et al.  A corresponding states correlation of saturated liquid volumes , 1971 .

[18]  S. Dzyuba,et al.  Influence of structural variations in 1-alkyl(aralkyl)-3-methylimidazolium hexafluorophosphates and bis(trifluoromethyl-sulfonyl)imides on physical properties of the ionic liquids. , 2002, Chemphyschem : a European journal of chemical physics and physical chemistry.

[19]  George H. Thomson,et al.  A new correlation for saturated densities of liquids and their mixtures , 1979 .

[20]  Lewis C. Yen,et al.  A generalized equation for computer calculation of liquid densities , 1966 .

[21]  Harold G. Rackett.  Equation of state for saturated liquids , 1970 .

[22]  Jacobo Troncoso,et al.  Viscosity-induced errors in the density determination of room temperature ionic liquids using vibrating tube densitometry , 2007 .

[23]  Mahmood Moshfeghian,et al.  A simplified method for calculating saturated liquid densities , 2004 .

[24]  Cynthia D. Holcomb,et al.  A theoretically-based calibration and evaluation procedure for vibrating-tube densimeters , 1998 .

[25]  Ryo Kato,et al.  Systems with ionic liquids: Measurement of VLE and γ ∞ data and prediction of their thermodynamic behavior using original UNIFAC, mod. UNIFAC(Do) and COSMO-RS(Ol) , 2005 .

[26]  Calvin F. Spencer,et al.  Improved equation for prediction of saturated liquid density , 1972 .

[27]  Po-Yu Chen,et al.  Electrodeposition of cesium at mercury electrodes in the tri-1-butylmethylammonium bis((trifluoromethyl)sulfonyl)imide room-temperature ionic liquid , 2004 .

[28]  R. D. Gunn,et al.  saturated liquid molar volumes. Rackett equation , 1973 .