Surface Tension of Ionic Liquids Analogues Using the QSPR Correlation

Abstract

Abstract-Deep eutectic solvents (DESs) are mixture complexes being introduced in many applications due to their favorable physicochemical characteristics. However, due to the lack of experimental data, prediction of their physical properties is challenging. One of the important physical properties that provides considerable insight of the molecular influence on intensity of interactions in the mixture is the surface tension. In this work, the QSPR prediction method was employed to predict the DESs surface tension. The parachors of selected DESs based on ammonium and phosphunium salts were determined experimentally and also calculated from the molecular structure of their constituting components using available parachor contribution data for neutral compounds. The results showed that the calculated and experimental parachors of DESs were notably comparable and the parachor contribution data developed for neutral compounds can be successfully utilized for DESs. The calculated parachors were employed to predict the surface tension using their experimental densities values.Index Terms-Surface tension, deep eutectic solvents, prediction. I. INTRODUCTIONThe growing number of publications in Deep Eutectic Solvents (DESs) literature reveals that they are gaining much attention by the scientific community. This is due to their potential as environment friendly solvents and advantages over conventional solvents and ionic liquids such as non-toxicity, non-reactivity with water and above all being biodegradable [1]. Moreover, they are synthesized easily in high purity at low cost in contrast to Ionic liquids which are very expensive and difficult to handle [2]. One of the fascinating features of using DESs is their potential as tunable solvents that can be customized to a particular type of chemistry. Surface tension is one of the essential DESs physical properties. Its evaluation is necessary to resolve various industrial related problems and develop new separation technologies. The awareness of this property provides considerable information of the molecular influence on the intensity of interactions in the mixture. Furthermore, the surface tension plays an important role in mass transfer processes like distillation, absorption, separation and extraction [3]. The experimental values for DESs surface Manuscript received January 5, 2013; received March 9, 2013. F. S. Mjalli is with Petroleum and Chemical Engineering Department, Sultan Qaboos University, Oman (e-mail: farouqsm@yahoo.com).K. Shahbaz is with the School of Engineering, Taylor's University, 47500 Selangor, Malaysia (e-mail: shahbaz.kaveh@gmail.com).M. A. Hashim is with University of Malaya, Chemical Engineering Department, Kuala Lumpur, Malaysia (e-mail: alihashim@um.edu.my).I. M. AlNashef is with King Saud University, Chemical Engineering Department, Riyadh, Saudi Arabia (e-mail: alnashef@ksu.edu.sa). tension are either rare or even absent. It is also impractical to experimentally evaluate surface tension in many cases. Thus, prediction methods for surface tens...