Ionic liquids surface tension prediction based on enthalpy of vaporization (original) (raw)
Related papers
Prediction of surface tension of ionic liquids by molecular approach
Journal of Molecular Liquids, 2013
Originally, Quantitative Structure Property Relationship (QSPR) models for the surface tension of ionic liquids are developed based on molecular descriptors. A large data set of 930 experimental surface tension data points for 48 ionic liquids is applied to derive the model. Seven descriptors are selected by genetic function approximation to relate the surface tension of ionic liquids to their corresponding anions and cation structures. To capture the nonlinear nature of surface tension, a model based on Least-Squared Supported Vector Machine (LSSVM) is also developed. The derived models are authenticated with several statistical validation techniques.
Density and Surface Tension of Ionic Liquids [H 2 N–C 2 mim][PF 6 ] and [H 2 N–C 3 mim][PF 6 ]
Journal of Chemical & Engineering Data, 2012
Two amino functionalized ionic liquids 1-(2-aminoethyl)-3-methylimidazolium hexafluorophosphate, [H 2 N−C 2 mim][PF 6 ], and 1-(3-aminopropyl)-3-methylimidazolium hexafluorophosphate, [H 2 N− C 3 mim][PF 6 ], were synthesized and characterized. The density and surface tension of these ionic liquids were measured from (293.15 to 343.15) K. Their values decreased with increasing temperature. The physical properties such as coefficient of thermal expansion, molecular volume, standard molar entropy, lattice energy, and molar enthalpy of vaporization were estimated using experimental data. The critical temperature of the ionic liquids was estimated using Eoẗvos equations. The values were then used to estimate the boiling temperature of the ionic liquids according to methods of Rebelo. The interstice model was used to predict the thermal expansion coefficient of the ionic liquids, α, and the result was in very good agreement with the experimental value. In addition, the parachor method was used to predict the physical properties of the ionic liquids [H 2 N−C n mim][PF 6 ] (n = 4, 5, 6).
Thermochimica Acta, 2014
The recent continuing interest in deep eutectic solvents (DES) as ionic liquids analogues and their successful applications in different areas of separation necessities the existence of reliable physical and thermodynamic properties database. The scarcity of data on the physical properties of such solvents, increases the need for their prediction using reliable methods. In this study, first the critical temperatures of eight DES systems have been calculated based on the Eötvos empirical equation using the experimental data of the density and surface tension at various temperatures, then the density and surface tension values of these systems were predicted from the calculated critical temperatures. For the density prediction the Eötvos and Guggenheim equations were combined to introduce a simple power law equation using the estimated critical temperatures from the Eötvos and the Modified Lydersen-Joback-Reid group contribution methods. Finally, the estimated critical temperatures by these two methods were used in the Guggenheim empirical equation to calculate the surface tension of the DES systems. The prediction quality of the two physical properties under investigation were compared and proper recommendations were postulated.
Surface tension measurements of imidazolium-based ionic liquids at liquid–vapor equilibrium
Fluid Phase Equilibria, 2008
A series of high quality 1-alkyl-3-methylimidazolium-based ionic liquids are synthesized and used for studying their surface tension. The capillary rise method is used for measuring the surface tension of I − , Cl − , PF 6 − , and BF 4 − salts in the temperature range 298-393 K. The capillary apparatus is evacuated and sealed under vacuum. The experimental results show that surface tension of these compounds depend systematically on temperature.
Industrial & Engineering Chemistry Research, 2017
A neural network-based group contribution method was developed in order to estimate the temperature-dependent surface tension of pure ionic liquids. A metaheuristic algorithm called gravitational search algorithm was employed in substitution of the traditional backpropagation learning algorithm to optimize the update weights of our neural network model. A total of 2307 experimental data points from 229 data sets of 162 different ionic liquid types, such as imidazolium, ammonium, phosphonium, pyridinium, pyrrolidinium, piperidinium, and sulfonium, were collected from the specialized literature. In this database, a wide temperature range from 263 to 533 K, and a wide surface tension range from 0.015 to 0.062 N•m −1 , were covered. The input parameters contained the following properties: absolute temperature, the molecular weight of the ionic liquid, and 46 structural groups that composed the molecule. The accuracy of the proposed method was checked using the mean absolute percentage error (MAPE) and the correlation coefficient (R) between the calculated and experimental values. The results show that, for the training phase, our method presents a MAPE = 1.17% and R= 0.998, while for the prediction phase, the method shows a MAPE = 1.29% and R = 0.991. In addition, the relative contribution of each input parameter was calculated from the optimal weights of the network. Also, the effects of the temperature, molecular weight, and cation and anion types on the estimation of the surface tension were analyzed. Finally, the proposed method was compared with other methods available in the literature. All results demonstrated the high accuracy of our method to estimate the temperature-dependent surface tension for several ionic liquid types.
Surface tension of ionic liquids and ionic liquid solutions
2012
Some of the most active scientific research fronts of the past decade are centered on ionic liquids. These fluids present characteristic surface behavior and distinctive trends of their surface tension versus temperature. One way to explore and understand their unique nature is to study their surface properties. This critical review analyses most of the surface tension data reported between 2001 and 2010 (187 references).
Group contribution model for estimation of surface tension of ionic liquids
Chemical Engineering Science, 2012
c A reliable group contribution method is presented for estimation of surface tension of ionic liquids. c It employs a total of 19 sub-structures plus temperature to predict the surface tension of 51 ionic liquids. c Results of this method show an average absolute relative deviation of 3.6% from experimental data.
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 %.
Applying a QSPR correlation to the prediction of surface tensions of ionic liquids
Ionic liquids (ILs) have attracted large amount of interest due to their unique properties. Although large effort has been focused on the investigation of their potential application, characterization of ILs properties and structure–property relationships of ILs are poorly understood. Computer aided molecular design (CAMD) of ionic liquids (ILs) can only be carried if predictive computational methods for the ILs properties are available. The limited availability of experimental data and their quality have been preventing the development of such tools. Based on experimental surface tension data collected from the literature and measured at our laboratory, it is here shown how a quantitative structure–property relationship (QSPR) correlation for parachors can be used along with an estimation method for the densities to predict the surface tensions of ILs. It is shown that a good agreement with literature data is obtained. For circa 40 ionic liquids studied a mean percent deviation (MPD) of 5.75% with a maximum deviation inferior to 16% was observed. A correlation of the surface tensions with the molecular volumes of the ILs was developed for estimation of the surface tensions at room temperature. It is shown that it can describe the experimental data available within a 4.5% deviation. The correlations here developed can thus be used to evaluate the surface tension of ILs for use in process design or in the CAMD of new ionic liquids.