Generalized correlations for calculating the density of ionic liquids at 0.1 MPa and higher pressures (original) (raw)
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On the evaluation of density of ionic liquids: towards a comparative study
Chemical Engineering Research and Design, 2019
Highlights A new group contribution model was developed for predicting density of ionic liquids The model inputs are temperature, pressure, and 47 substructures A data bank containing 918 data points for 747 different ILs was used for the model Results indicate satisfactory predictions of suggested model than other existing models An outlier analysis was utilized to detect suspected data points
Journal of Chemical & Engineering Data, 2008
The density of ionic liquids (ILs) as a function of pressure and temperature has been modeled using a group contribution model. This model extends the calculations previously reported (Jacquemin et al. J. Chem. Eng. Data 2008) which used 4000 IL densities at 298.15 K and 600 IL densities as a function of temperature up to 423 K at 0.1 MPa to pressures up to 207 MPa by using described data in the literature and presented in this study. The densities of two different ionic liquids (butyltrimethylammonium bis(trifluoromethylsulfonyl)imide, [N 1114 ][NTf 2 ], and 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide, [C 4 mPyrro]-[NTf 2 ]) were measured as a function of temperature from (293 to 415) K and over an extended pressure range from (0.1 to 40) MPa using a vibrating-tube densimeter. The model is able to predict the ionic liquid densities of over 5080 experimental data points to within 0.36 %. In addition, this methodology allows the calculation of the mechanical coefficients using the calculated density as a function of temperature and pressure with an estimated uncertainty of ( 20 %.
An extension of the Ye and Shreeve group contribution method [C. Ye, J.M. Shreeve, J. Phys. Chem. A 111 (2007) 1456-1461 for the estimation of densities of ionic liquids (ILs) is here proposed. The new version here presented allows the estimation of densities of ionic liquids in wide ranges of temperature and pressure using the previously proposed parameter table. Coefficients of new density correlation proposed were estimated using experimental densities of nine imidazolium-based ionic liquids. The new density correlation was tested against experimental densities available in literature for ionic liquids based on imidazolium, pyridinium, pyrrolidinium and phosphonium cations. Predicted densities are in good agreement with experimental literature data in a wide range of temperatures (273.15-393.15 K) and pressures (0.10-100 MPa). For imidazolium-based ILs, the mean percent deviation (MPD) is 0.45% and 1.49% for phosphonium-based ILs. A low MPD ranging from 0.41% to 1.57% was also observed for pyridinium and pyrrolidinium-based ILs.
Industrial & Engineering Chemistry Research
The volumetric properties of 81 different ionic liquids (ILs) have been modeled as a function of temperature and pressure using an extended version of the group contribution method previously reported by our group (Jacquemin et al. J. Chem. Eng. Data 2008, 53, 716−726). Prior to correlating collected data from the literature using this model, the mathematical gnostics was used to critically analyze experimental density data sets as a function of temperature (from 217− 473 K) and pressure (from 0.1−207 MPa) to be then able to recommend one data set for each IL. In addition, recommended density data sets were then fitted as a function of temperature and pressure using a series of mathematical equations reported in the literature. These fitting equations were then assessed through the comparison of the calculated mechanical coefficients with the limited directly measured experimental data reported in the literature. Among these recommended data sets, 5399 density data points for 54 different ILs were then used as the training data set to determine the temperature and pressure dependences on the effective molar volume of 31 different cations and 24 different anions. Then 2522 density data points for 27 other ILs were used as a test data set to determine the accuracy of this method. In light of this analysis, excellent agreement was observed between calculated and recommended literature data within the whole temperature and pressure ranges investigated herein as stated by the overall relative average absolute deviation (RAAD) for each volumetric property, which was lower than 0.31% and 3.5% in the case of the density and isobaric thermal expansion coefficient of pure ILs, respectively. Finally, this model was further assessed with other methods reported in the literature in the case of the evaluation of the density of binary mixtures of two ILs as a function of temperature at atmospheric pressure. This analysis demonstrates that the proposed method shows a good ability to evaluate the density even in the case of mixture of ILs with a RAAD lower than 0.25%.
New Analytical Expression for the Prediction of Vapour Pressures of Ionic Liquids
Indian Chemical Engineer, 2014
Ionic liquids (IL), considered as green solvents, are useful in different industrial applications. Vapour pressure is one of the key properties of IL for designing different processes. Recently, the zero pressure fugacity approach was proposed to predict the vapour pressures of IL using cubic equations of state. In the present work, this approach was improved by fitting the vapour pressure data of ten ILs using six different cohesion factor models. New analytical expressions are proposed in the present work for predicting vapour pressure of IL using acentric factor and Mass Connectivity Index. It was shown that one of the proposed models (Model J) predicts vapour pressure with global %AAD of 7.3%. The model compared with the models based on COSMO-RS theory and PC SAFT-equation of state (EOS), and it was found that the proposed models work well compared to others. It is shown that the proposed models predict vapour pressure with greater accuracy and consistency.
Generalized Pitzer Correlation for Density Calculations of Ionic Liquids
ASEAN Journal of Chemical Engineering
The density of ionic liquids is an important design parameter for its utilization as a chemical process solvent. In this study, a generalized Pitzer-type correlation for calculating the density of ionic liquids with the use of reduced temperature (TR), reduced pressure (PR), and acentric factor (ω) as parameters is proposed. Experimental density data were obtained from several references through the IUPAC Ionic Liquids Database. Expansion of the terms as well as integrating the ionic liquid molecular weight was attempted to determine the accuracy improvement of the model in predicting densities at 0.1 MPa. Then, the obtained model was modified by further truncation to include the pressure effects for densities at higher pressures. MATLAB software was used to determine the optimal virial coefficients for the proposed correlations. The percent average absolute deviation (%AAD) was applied to calculate the variation between the experimental and calculated density values. It was conclud...
An extension of the Ye and Shreeve group contribution method [C. Ye, J.M. Shreeve, J. Phys. Chem. A 111 (2007) 1456–1461] for the estimation of densities of ionic liquids (ILs) is here proposed. The new version here presented allows the estimation of densities of ionic liquids in wide ranges of temperature and pressure using the previously proposed parameter table. Coefficients of new density correlation proposed were estimated using experimental densities of nine imidazolium-based ionic liquids. The new density correlation was tested against experimental densities available in literature for ionic liquids based on imidazolium, pyridinium, pyrrolidinium and phosphonium cations. Predicted densities are in good agreement with experimental literature data in a wide range of temperatures (273.15–393.15 K) and pressures (0.10–100 MPa). For imidazolium-based ILs, the mean percent deviation (MPD) is 0.45% and 1.49% for phosphonium-based ILs. A low MPD ranging from 0.41% to 1.57% was also observed for pyridinium and pyrrolidinium-based ILs.
Density calculation of ionic liquids
2017
Recently, an interest from both academia and industry has been moved toward ionic liquids due to their environmentally friendly characteristics as green alternative for traditional volatile organic solvents (VOCs). In addition, because of their wide range of physicochemical properties they found unique applications in renewable energy sector. For using such substances, one needs reliable correlations for predicting their physical properties. In the present work, a new method for determining the density of ionic liquids has been proposed. It has been shown that density of ionic liquids appears to be correlated linearly with the refractive index parameter of these liquids. An average error of 12.27% for 45 ionic liquids was obtained. Several equations of state were compared with this method including, SRK, RK, Peng Robinson and Riazi and Roomi [1]. Using a sample of 29 ionic liquids, average errors of 88.72%, 65.79%, 39.10% and 66.07% were obtained for these equations of state, respec...
Industrial & Engineering Chemistry Research, 2010
Based on the electrolyte perturbation theory, a group contribution equation of state that embodies hardsphere repulsion, dispersive attraction, and ionic electrostatic interaction energy was established to calculate the density of ionic liquids (ILs). According to this method, each ionic liquid is divided into several groups representing cation, anion, and alkyl substituents. The performance of the model was examined by describing the densities of a large number of imidazolium-based ILs over a wide range of temperatures (293.15-414.15 K) and pressures (0.1-70.43 MPa). A total number of 202 data points of density for 12 ILs and 2 molecular liquids (i.e., 1-methylimidazole and 1-ethylimidazole) were used to fit the group parameters, namely, the soft-core diameter σ and the dispersive energy ε. The resulting group parameters were used to predict 961 data points of density for 29 ILs at varying temperatures and pressures. The model was found to estimate well the densities of ionic liquids with an overall average relative deviation (ARD) of 0.41% for correlation and an ARD of 0.63% for prediction, which demonstrates the applicability of the model and the rationality of the soft-core diameter and dispersive energy parameters.
Generalized PSRK Model for Prediction of Liquid Density of Ionic Liquids
Procedia Engineering, 2013
A simple and generalised expression for adjustable parameter for pure ionic liquids in conjunction with predictive-Soave-Redlich-Kwong (PSRK) approach is presented for prediction of pure IL density. The proposed expression is based on the correlation developed by Nasrifar and Moshfeghian for perfection of saturated liquid density for pure compounds. The generalized expression uses acentric factor and mass connectivity index of pure ionic liquids. A set of 47 pure ionic liquids with 735 data points and 4 different cohesion functions were used in the study. The results were compared with linear generalized model (LGM) developed by Valderrama to check appropriateness and accuracy of expression presented. It was found that the compound specific PSRK approach gives very accurate predictions and generalized expression is at par with LGM model. Further study would include use of other cohesion factor models.