Solid–liquid equilibria of binary mixtures of fluorinated ionic liquids

Abstract

Within ionic liquids, fluorinated ionic liquids (FILs) present unique physico-chemical properties and potential applications in several fields. However, the melting point of these neoteric compounds is usually higher due to the presence of fluorine atoms. This drawback may be resolved by, for instance, mixing different FILs to create eutectic mixtures. In this work, binary mixtures of fluoro-containing and fluorinated ionic liquids were considered with the aim of decreasing their melting temperatures as well as understanding and characterizing these mixtures and their phase transitions. Five FILs were selected, allowing the investigation of four binary mixtures, each of them with a common ion. Their solid-liquid and solid-solid equilibria were studied by differential scanning calorimetry and the non-ideality of the mixtures was investigated. Overall, a variety of solid-liquid equilibria with systems exhibiting eutectic behavior, polymorphs with solid-solid phase transitions, and the formation of intermediate compounds and solid solutions were surprisingly found. In addition to these intriguing behaviours, novel FILs with lower melting temperatures were obtained by the formation of binary systems, thus enlarging the application range of FILs at lower temperatures.

The Role of Charge Transfer in the Formation of Type I Deep Eutectic Solvent-Analogous Ionic Liquid Mixtures

“…These tuneable solvents are of interest for a wide range of applications, including synthesis, catalysis [1], energy storage [2], metal extraction and separation [3], carbon capture [4], and biomass dissolution [5] amongst others. A natural extension of the design versatility of ILs is the further fine-tuning of their physicochemical properties through the use of binary mixtures of these substances, which are also referred to as eutectic ILs [6,7,8,9,10,11]. For a given temperature, eutectic solvents (ES) may be defined as liquid mixtures, usually binary, composed of substances that when pure are often solid at that temperature.…”

Influence of Fluorination on the Solubilities of Carbon Dioxide, Ethane, and Nitrogen in 1-n-Fluoro-alkyl-3-methylimidazolium Bis(n-fluoroalkylsulfonyl)amide Ionic Liquids

“…6 In ionic liquids, the capacity and selectivity toward gas absorption can be tuned either by choosing appropriately the cation-anion pairs 7 or by modifying the ions, including chemical structures that render the liquid specific for a given task. 8,9 Recent works have reported the physicochemical properties 10,11,12 and possible applications 13 including the gas absorption 14,15,16,17,18 , of a large variety of ionic liquids containing fluorinated or partially fluorinated chains. The liquids studied therein are varied, with cations and anions presenting a diversity of molecular structures, the only common point being the presence of fluorinated moieties.…”

Thermophysical Characterization of Ionic Liquids Based on the Perfluorobutanesulfonate Anion: Experimental and Soft‐SAFT Modeling Results

“…Given the plethora of cations and anions combinations available to form FILs, modeling becomes a useful tool to reduce the experimental work and predict the behavior of these compounds, which may accelerate their actual implementation for specific applications. Several different approaches may be used for FILs modeling .…”

“…Given the plethora of cations and anionsc ombinations available to form FILs, [34] modeling becomes au seful toolt or educe the experimental work and predict the behavior of these compounds, which may accelerate their actuali mplementation for specifica pplications.S everal different approaches may be used for FILs modeling. [35] The Statistical Associating Fluid Theory [36] (SAFT)i samolecular-based equation of state (EoS) based on statistical thermodynamicsc oncepts.…”