Deep eutectic solvents (DESs) are an emerging class of mixtures characterized by significant depressions in melting points compared to those of the neat constituent components. These materials are promising for applications as inexpensive "designer" solvents exhibiting a host of tunable physicochemical properties. A detailed review of the current literature reveals the lack of predictive understanding of the microscopic mechanisms that govern the structure-property relationships in this class of solvents. Complex hydrogen bonding is postulated as the root cause of their melting point depressions and physicochemical properties; to understand these hydrogen bonded networks, it is imperative to study these systems as dynamic entities using both simulations and experiments. This review emphasizes recent research efforts in order to elucidate the next steps needed to develop a fundamental framework needed for a deeper understanding of DESs. It covers recent developments in DES research, frames outstanding scientific questions, and identifies promising research thrusts aligned with the advancement of the field toward predictive models and fundamental understanding of these solvents.

Deep Eutectic Solvents: A Review of Fundamentals and Applications.

Sustainable technologies applied to energy-related applications should develop a pivotal role in the next decades. In particular, carbon dioxide capture from flue gases emitted by fossil-fueled power plants should play a pivotal role in controlling and reducing the greenhouse effect. Therefore, the development of new materials for carbon capture purposes has merged as central research line, for which many alternatives have been proposed. Ionic liquids (ILs) have emerged as one of the most promising choices for carbon capture, but in spite of their promising properties, some serious drawbacks have also appeared. Deep eutectic solvents (DESs) have recently been considered as alternatives to ILs that maintain most of their relevant properties, such as task-specific character, and at the same time avoid some of their problems, mainly from economic and environmental viewpoints. DES production from low-cost and natural sources, together with their almost null toxicity and total biodegradability, makes these sol...

Deep Eutectic Solvents: Physicochemical Properties and Gas Separation Applications

Deep eutectic solvents for the production and application of new materials

Deep Eutectic Solvents

High cost and high energy penalty for CO2 uptake from flue gases are important obstacles in large-scale industrial applications, and developing efficient technology for CO2 capture from technical a ...

Carbon Dioxide Capture with Ionic Liquids and Deep Eutectic Solvents: A New Generation of Sorbents

During the past few years, there has been a surge in interest and research in the arena of utilizing deep eutectic solvents (DESs) as green solvents. This manifested in applying DESs in a variety of industrial applications. Most of the reported work in this field was directed toward the choline chloride-based DES. Recently, the area of DES synthesis was widened by considering other quaternary ammonium and phosphonium salts. In this work tetrabutylammonium chloride (TBAC) is used as a salt for the synthesis of three different DES systems based on three different hydrogen bond donors (HBDs), namely, glycerol, ethylene glycol, and triethylene glycol. Screening tests for each DES system was performed to identify salt:HBD ratios that exhibit a minimum freezing point, and at least three such ratios were selected for each system. Physical properties including melting point, density, viscosity, surface tension, refractive index, conductivity, and pH were measured for the three DES systems at different temperature...

Tetrabutylammonium Chloride Based Ionic Liquid Analogues and Their Physical Properties

New tetrapropylammonium bromide-based deep eutectic solvents: Synthesis and characterizations

In this work, a viscosity model for choline chloride-based deep eutectic solvents (DESs) was developed. In addition to temperature, the new model presented here considers the composition of the salt in the DES, which was not the case for all previously reported viscosity models. Two forms of the proposed model were optimized and fitted to viscosity experimental data. The developed model was tested using the experimental viscosity values for nine common choline chloride-based DES systems of different hydrogen bond donors. The performance of the model was evaluated using three different statistical indicators, namely average relative deviation, correlation coefficient (R2) and standard deviation. In addition, a significance t-test was also conducted on each of the fitted DES viscosity data. The statistical indicators showed a very good agreement between the model-predicted viscosity and the experimental viscosity values for the DESs with relatively low viscosities (DES1, DES2, DES4 and DES5). For DESs with high viscosities (DES3, DES7, DES8 and DES9), the second model gave better predictions. Overall, this proposed model was capable of predicting DES viscosities for different salt compositions at different temperatures as supported by the statistical significance t-test and other statistical indicators. © 2015 Curtin University of Technology and John Wiley & Sons, Ltd.

Viscosity model for choline chloride-based deep eutectic solvents

A solar unit to investigate the effect of PCM on the temperature change of the water during the entire day (day time and night time) was designed. The unit is also used to test the effect of PCM on the amount of fresh water produced. Candle wax (tricosane) was used as PCM and its amount was varied to achieve the ratio of mass of PCM to mass of water of 0, 0.17, 0.35 and 0.51 respectively. The amount of water used was fixed throughout all the experiment at 3 kg tap water. The wax was placed in copper tubes immersed in water. The results showed that presence of PCM causes the appearance of two zones in which the temperature is strongly affected by the PCM. The first zone appears due to the melting of the PCM (during day time) and the second zone appears due to solidification (during night time) of the PCM. The effect of the PCM is prominent in the second zone where the temperature remains constant at the PCM melting point. The length of the solidification zone is proportional to the amount of PCM. Fresh water production is strongly affected by the presence of the PCM. During the day time fresh water production is inversely proportion to the value of R. However, during the night time fresh water production is directly proportional to the value of R.

Jamil Naser

Papers

Tetrabutylammonium Chloride Based Ionic Liquid Analogues and Their Physical Properties

New tetrapropylammonium bromide-based deep eutectic solvents: Synthesis and characterizations

Viscosity model for choline chloride-based deep eutectic solvents

Experimental study and analysis of solar still desalination using phase change materials

Ionic liquids analogues based on potassium carbonate