Eutectics: formation, properties, and applications

2021 ◽  
Author(s):  
Dongkun Yu ◽  
Zhimin Xue ◽  
Tiancheng Mu
Keyword(s):  
Deep Eutectic Solvents ◽  
Eutectic Systems

Various eutectic systems including eutectic metals, eutectic salts, and deep eutectic solvents have been proposed and applied in engineering, energy and environmental fields.

scholarly journals Design of Deep Eutectic Systems: A Simple Approach for Preselecting Eutectic Mixture Constituents

Molecules ◽  
2020 ◽  
Vol 25 (5) ◽  
pp. 1077 ◽  
Author(s):  
Ahmad Alhadid ◽  
Liudmila Mokrushina ◽  
Mirjana Minceva
Keyword(s):  
Binary Systems ◽  
Eutectic Temperature ◽  
Eutectic Mixture ◽  
Deep Eutectic Solvents ◽  
Simple Approach ◽  
Molecular Structures ◽  
Melting Enthalpy ◽  
Wide Range ◽  
Eutectic Systems ◽  
Melting Entropy

Eutectic systems offer a wide range of new (green) designer solvents for diverse applications. However, due to the large pool of possible compounds, selecting compounds that form eutectic systems is not straightforward. In this study, a simple approach for preselecting possible candidates from a pool of substances sharing the same chemical functionality was presented. First, the melting entropy of single compounds was correlated with their molecular structure to calculate their melting enthalpy. Subsequently, the eutectic temperature of the screened binary systems was qualitatively predicted, and the systems were ordered according to the depth of the eutectic temperature. The approach was demonstrated for six hydrophobic eutectic systems composed of L-menthol and monocarboxylic acids with linear and cyclic structures. It was found that the melting entropy of compounds sharing the same functionality could be well correlated with their molecular structures. As a result, when the two acids had a similar melting temperature, the melting enthalpy of a rigid acid was found to be lower than that of a flexible acid. It was demonstrated that compounds with more rigid molecular structures could form deeper eutectics. The proposed approach could decrease the experimental efforts required to design deep eutectic solvents, particularly when the melting enthalpy of pure components is not available.

scholarly journals Metastable crystalline phase formation in deep eutectic systems revealed by simultaneous synchrotron XRD and DSC

2020 ◽  
Vol 56 (73) ◽  
pp. 10726-10729
Author(s):  
Charlie L. Hall ◽  
Jason Potticary ◽  
Victoria Hamilton ◽  
Simon Gaisford ◽  
Asma Buanz ◽  
...  
Keyword(s):  
Phase Formation ◽  
Crystalline Phase ◽  
Deep Eutectic Solvents ◽  
Eutectic Systems ◽  
First Time ◽  
Synchrotron Xrd

For the first time, simultaneous pXRD and DSC is used to investigate the crystallinity of deep eutectic solvents upon cooling.

scholarly journals Connecting chloride solvation with hydration in deep eutectic systems

2021 ◽  
Vol 23 (1) ◽  
pp. 107-111
Author(s):  
Maria Enrica Di Pietro ◽  
Oliver Hammond ◽  
Adriaan van den Bruinhorst ◽  
Alberto Mannu ◽  
Agilio Padua ◽  
...  
Keyword(s):  
Water Content ◽  
Deep Eutectic Solvents ◽  
Md Simulations ◽  
Eutectic Systems

The Deep Eutectic Solvents (DESs) choline chloride:urea (xChCl = 0.33) and choline chloride:glycolic acid (xChCl = 0.5) were studied using viscosity-corrected 35Cl NMR and MD simulations to probe the role of chloride as a function of water content.

scholarly journals Influence of the Molecular Structure of Constituents and Liquid Phase Non-Ideality on the Viscosity of Deep Eutectic Solvents

Molecules ◽  
2021 ◽  
Vol 26 (14) ◽  
pp. 4208
Author(s):  
Ahmad Alhadid ◽  
Liudmila Mokrushina ◽  
Mirjana Minceva
Keyword(s):  
Molecular Structure ◽  
Melting Temperature ◽  
Deep Eutectic Solvents ◽  
Liquid Solution ◽  
High Viscosity ◽  
Molar Ratio ◽  
Natural Substances ◽  
Low Viscosity ◽  
Wide Range ◽  
Eutectic Systems

Hydrophobic deep eutectic solvents (DES) have recently been used as green alternatives to conventional solvents in several applications. In addition to their tunable melting temperature, the viscosity of DES can be optimized by selecting the constituents and molar ratio. This study examined the viscosity of 14 eutectic systems formed by natural substances over a wide range of temperatures and compositions. The eutectic systems in this study were classified as ideal or non-ideal based on their solid–liquid equilibria (SLE) data found in the literature. The eutectic systems containing constituents with cyclohexyl rings were considerably more viscous than those containing linear or phenyl constituents. Moreover, the viscosity of non-ideal eutectic systems was higher than that of ideal eutectic systems because of the strong intermolecular interactions in the liquid solution. At temperatures considerably lower than the melting temperature of the pure constituents, non-ideal and ideal eutectic systems with cyclohexyl constituents exhibited considerably high viscosity, justifying the kinetic limitations in crystallization observed in these systems. Overall, understanding the correlation between the molecular structure of constituents, SLE, and the viscosity of the eutectic systems will help in designing new, low-viscosity DES.

Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Deep Eutectic Solvents ◽  
Structural Features ◽  
Solvation Dynamics ◽  
Structured Systems ◽  
Reduced Viscosity ◽  
Bond Network ◽  
Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

Probing the Structural Features and the Micro-heterogeneity of Various Deep Eutectic Solvents and their Water Dilutions by the Photophysical Behaviour of Two Fluorophores

2020 ◽  
Author(s):  
Matteo Tiecco ◽  
Irene Di Guida ◽  
Pier Luigi Gentili ◽  
Raimondo Germani ◽  
Carmela Bonaccorso ◽  
...  
Keyword(s):  
Hydrogen Bond ◽  
Transient Absorption ◽  
Photophysical Properties ◽  
Deep Eutectic Solvents ◽  
Structural Features ◽  
Solvation Dynamics ◽  
Structured Systems ◽  
Reduced Viscosity ◽  
Bond Network ◽  
Fluorescent Molecules

<div><div><div><p>The structural features of a series of diverse Deep Eutectic Solvents (DESs) have been investigated and characterized by means of two fluorescent probes. The spectral and photophysical properties of the latter are strictly dependent on the experienced environment, so that they can provide insights into the polarity, viscosity, hydrogen-bond network, and micro-heterogeneity of the various DESs.</p><p>In fact, the investigated DESs exhibit a variety of properties with regards to their hydrophilicity, acidity, and hydrogen-bond ability, and these details were deeply probed by the two fluorescent molecules. The effect of the addition of water, which is a key strategy for tuning the properties of these structured systems, was also tested. In particular, the excited state dynamics of the probes, measured by femtosecond-resolved transient absorption, proved instrumental in understanding the changes in the structural properties of the DESs, namely reduced viscosity and enhanced heterogeneity, as the water percentage increases. Differences between the various DESs in terms of both local microheterogeneity and bulk viscosity also emerged from the peculiar multi-exponential solvation dynamics undergone by the excited states of the probes.</p></div></div></div>

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