http://pubs.acs.org/doi/pdfplus/10.1021/cr300162p

Deep Eutectic Solvents (DESs) and Their Applications

Within the framework of green chemistry, solvents occupy a strategic place. To be qualified as a green medium, these solvents have to meet different criteria such as availability, non-toxicity, biodegradability, recyclability, flammability, and low price among others. Up to now, the number of available green solvents are rather limited. Here we wish to discuss a new family of ionic fluids, so-called Deep Eutectic Solvents (DES), that are now rapidly emerging in the current literature. A DES is a fluid generally composed of two or three cheap and safe components that are capable of self-association, often through hydrogen bond interactions, to form a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. These DESs exhibit similar physico-chemical properties to the traditionally used ionic liquids, while being much cheaper and environmentally friendlier. Owing to these remarkable advantages, DESs are now of growing interest in many fields of research. In this review, we report the major contributions of DESs in catalysis, organic synthesis, dissolution and extraction processes, electrochemistry and material chemistry. All works discussed in this review aim at demonstrating that DESs not only allow the design of eco-efficient processes but also open a straightforward access to new chemicals and materials.

Deep eutectic solvents: syntheses, properties and applications

Green technology actively seeks new solvents to replace common organic solvents that present inherent toxicity and have high volatility, leading to evaporation of volatile organic compounds to the atmosphere. Over the past two decades, ionic liquids (ILs) have gained enormous attention from the scientific community, and the number of reported articles in the literature has grown exponentially. Nevertheless, IL “greenness” is often challenged, mainly due to their poor biodegradability, biocompatibility, and sustainability. An alternative to ILs are deep eutectic solvents (DES). Deep eutectic solvents are defined as a mixture of two or more components, which may be solid or liquid and that at a particular composition present a high melting point depression becoming liquids at room temperature. When the compounds that constitute the DES are primary metabolites, namely, aminoacids, organic acids, sugars, or choline derivatives, the DES are so called natural deep eutectic solvents (NADES). NADES fully represen...

Natural Deep Eutectic Solvents – Solvents for the 21st Century

How do molecules aggregate in solution, and how do these aggregates consolidate themselves in crystals? What is the relationship between the structure of a molecule and the structure of the crystal it forms? Why do some molecules adopt more than one crystal structure? Why do some crystal structures contain solvent? How does one design a crystal structure with a specified topology of molecules, or a specified coordination of molecules and/or ions, or with a specified property? What are the relationships between crystal structures and properties for molecular crystals? These are some of the questions that are being addressed today by the crystal engineering community, a group that draws from the larger communities of organic, inorganic, and physical chemists, crystallographers, and solid state scientists. This Perspective provides a brief historical introduction to crystal engineering itself and an assessment of the importance and utility of the supramolecular synthon, which is one of the most important concepts in the practical use and implementation of crystal design. It also provides a look to the future from the viewpoint of the author, and indicates some directions in which this field might be moving.

Crystal engineering: from molecule to crystal.

A new generation of designer solvents emerged in the last decade as promising green media for multiple applications, including separation processes: the low-transition-temperature mixtures (LTTMs). They can be prepared by mixing natural high-melting-point starting materials, which form a liquid by hydrogen-bond interactions. Among them, deep-eutectic solvents (DESs) were presented as promising alternatives to conventional ionic liquids (ILs). Some limitations of ILs are overcome by LTTMs, which are cheap and easy to prepare from natural and readily available starting materials, biodegradable, and renewable.

Low-transition-temperature mixtures (LTTMs): a new generation of designer solvents.

A study of sulfamerazine single crystals using atomic force microscopy, transmission light microscopy, and Raman spectroscopy

Development of piroxicam mini-tablets enabled by spherical cocrystallization.

Improving taste and tuning physicochemical properties of active pharmaceutical ingredients (API) by forming new salts or cocrystals with an artificial sweetener, such as saccharine (Sac) and acesulfame (Acs), is an effective crystal engineering strategy for facilitating successful delivery of bitter drugs. However, the number of reported solid forms of Acs is curiously lower (29) than that of Sac (275). An analysis of the literature revealed that the preparation of salts or cocrystals of Acs was hindered by the difficulty and cost in preparing Acs free acid from commercially available potassium salt (Acs-K). Here, we evaluated the broad applicability of an anion exchange reaction for preparing Acs solid forms using nine model compounds. In all cases, we successfully prepared Acs crystals, based on single crystal structure determination, simply from ion exchange between Acs-K and corresponding salts. The proton transfer propensity, hydrogen-bonding pattern, and amide group keto–enol tautomerism in the Acs ...

Anion Exchange Reaction for Preparing Acesulfame Solid Forms

Sulfamethizole (SMZ) is an antibiotic drug with good solubility but short in vivo half-life. Thus, reducing the dissolution rate is expected to improve bioavailability and therapeutic activity thro...

Changquan Calvin Sun

Papers

A study of sulfamerazine single crystals using atomic force microscopy, transmission light microscopy, and Raman spectroscopy

Development of piroxicam mini-tablets enabled by spherical cocrystallization.

Anion Exchange Reaction for Preparing Acesulfame Solid Forms

Structural Features of Sulfamethizole and Its Cocrystals: Beauty within

Relationship between hydrate stability and accuracy of true density measured by helium pycnometry.