New Method Based on the UNIFAC–VISCO Model for the Estimation of Ionic Liquids Viscosity Using the Experimental Data Recommended by Mathematical Gnostics

Nan Zhao,Johan Jacquemin,Volkan Degirmenci,Magdalena Bendová,Ryan Oozeerally,Zdeněk Wagner

doi:10.1021/acs.jced.6b00689

Abstract

The viscosity of ionic liquids (ILs) has been modeled as a function of temperature and at atmospheric pressure using a new method based on the UNIFAC–VISCO method. This model extends the calculations previously reported by our group (see Zhao et al. J. Chem. Eng. Data 2016, 61, 2160–2169) which used 154 experimental viscosity data points of 25 ionic liquids for regression of a set of binary interaction parameters and ion Vogel–Fulcher–Tammann (VFT) parameters. Discrepancies in the experimental data of the same IL affect the quality of the correlation and thus the development of the predictive method. In this work, mathematical gnostics was used to analyze the experimental data from different sources and recommend one set of reliable data for each IL. These recommended data (totally 819 data points) for 70 ILs were correlated using this model to obtain an extended set of binary interaction parameters and ion VFT parameters, with a regression accuracy of 1.4%. In addition, 966 experimental viscosity data po...

Highlights

Ionic liquids (ILs) have received significant attention due to their unique properties, such as nonvolatility, high chemical stability, and easy operation at the liquid state, and have become promising alternatives to traditional liquid solvents.[1−7] the viscosities of ionic liquids (ILs) are relatively high compared to those of traditional solvents and water.[8]
We present an extension of the previously developed method[33] based on the UNIFAC−VISCO model to evaluate the viscosity of 70 pure ILs and 11 binary ionic liquid mixtures
An extension of a previously reported method based on the UNIFAC−VISCO model has been made using 819 experimental data of 70 ILs in a temperature range from 263.15 to 373.15 K at 0.1 MPa

Summary

Introduction

Ionic liquids (ILs) have received significant attention due to their unique properties, such as nonvolatility, high chemical stability, and easy operation at the liquid state, and have become promising alternatives to traditional liquid solvents.[1−7] the viscosities of ILs are relatively high compared to those of traditional solvents and water.[8] the viscosity of ILs is a very important parameter in assessing various aspects of chemical processes; high viscosity can negatively affect mass transfer and power requirements for mixing in liquid−liquid systems. A low viscosity IL is desirable as a solvent in order to minimize pumping costs and increase mass transfer rates; while higher viscosity ILs could be favorable for other applications, such as lubrication, membranes,[9] etc. A variety of methods have been reported for the correlation/evaluation/prediction of IL viscosity.[9−29] Methods based on the different correlation equations which provide the correlation for viscosity usually describe the exponential behavior of the temperature dependency; such as the Vogel− Fulcher−Tamman (VFT) equation,[10−12] fluidity equation,[12] Litovitz equation,[12,13] Arrhenius equation,[12,14] power law equation,[15] and the Daubert and Danner correlation.[14]

Methods

Results

Conclusion