scholarly journals Biocatalyzed Redox Processes Employing Green Reaction Media

Molecules ◽  
2020 ◽  
Vol 25 (13) ◽  
pp. 3016
Author(s):  
Carmen Aranda ◽  
Gonzalo de Gonzalo
Keyword(s):  
Environmentally Friendly ◽  
Deep Eutectic Solvents ◽  
Chemical Processes ◽  
Redox Processes ◽  
Aqueous Buffer ◽  
Buffer Medium ◽  
Neoteric Solvents ◽  
Reaction Media

The application of biocatalysts to perform reductive/oxidative chemical processes has attracted great interest in recent years, due to their environmentally friendly conditions combined with high selectivities. In some circumstances, the aqueous buffer medium normally employed in biocatalytic procedures is not the best option to develop these processes, due to solubility and/or inhibition issues, requiring biocatalyzed redox procedures to circumvent these drawbacks, by developing novel green non-conventional media, including the use of biobased solvents, reactions conducted in neat conditions and the application of neoteric solvents such as deep eutectic solvents.

Stereoselective organocatalysed reactions in deep eutectic solvents: highly tunable and biorenewable reaction media for sustainable organic synthesis

2016 ◽  
Vol 18 (3) ◽  
pp. 792-797 ◽  
Author(s):  
Elisabetta Massolo ◽  
Silvia Palmieri ◽  
Maurizio Benaglia ◽  
Vito Capriati ◽  
Filippo M. Perna
Keyword(s):  
Organic Synthesis ◽  
Environmentally Friendly ◽  
Deep Eutectic Solvents ◽  
Chiral Catalyst ◽  
Metal Free ◽  
Extraction Protocol ◽  
Enantioselective Reactions ◽  
Simple Extraction ◽  
High Yields ◽  
Reaction Media

Different metal-free catalytic enantioselective reactions have been performed in high yields and enantioselectivity in natural, biorenewable and environmentally-friendly DESs. The recyclability of the chiral catalyst by a simple extraction protocol was also successfully accomplished.

scholarly journals Environmentally Friendly Techniques and Their Comparison in the Extraction of Natural Antioxidants from Green Tea, Rosemary, Clove, and Oregano

Molecules ◽  
2021 ◽  
Vol 26 (7) ◽  
pp. 1869
Author(s):  
Mariel Calderón-Oliver ◽  
Edith Ponce-Alquicira
Keyword(s):  
Green Tea ◽  
Electric Fields ◽  
Antioxidant Activities ◽  
Environmentally Friendly ◽  
Natural Antioxidants ◽  
Deep Eutectic Solvents ◽  
Extraction Methods ◽  
Extraction Techniques ◽  
Health Trends ◽  
Food Applications

Many current food and health trends demand the use of more ecological, sustainable, and environmentally friendly techniques for the extraction of bioactive compounds, including antioxidants. However, extraction yields and final antioxidant activities vary between sources and are highly influenced by the given extraction method and nature and ratio of the employed solvent, especially for total polyphenols, flavonoids, and anthocyanins, which are well recognized as natural antioxidants with food applications. This review focused on the most common extraction techniques and potential antioxidant activity in the food industry for various natural antioxidant sources, such as green tea, rosemary, clove, and oregano. Green extraction techniques have been proven to be far more efficient, environmentally friendly, and economical. In general, these techniques include the use of microwaves, ultrasound, high hydrostatic pressure, pulsed electric fields, enzymes, and deep eutectic solvents, among others. These extraction methods are described here, including their advantages, disadvantages, and applications.

Ionic liquids and supercritical carbon dioxide: green and alternative reaction media for chemical processes

2016 ◽  
Vol 32 (6) ◽  
Author(s):  
Ruixia Liu ◽  
Peng Zhang ◽  
Suojiang Zhang ◽  
Ting Yan ◽  
Jiayu Xin ◽  
...  
Keyword(s):  
Carbon Dioxide ◽  
Ionic Liquids ◽  
Supercritical Carbon Dioxide ◽  
Chemical Processes ◽  
Reaction Media ◽  
Supercritical Carbon

AbstractIonic liquids (ILs) and supercritical CO

Strategies for metal colloidal nancrystal synthesis in sustainable media

2019 ◽  
Author(s):  
◽  
Nakara Bhawawet
Keyword(s):  
Deep Eutectic Solvents ◽  
Chemical Processes ◽  
Green Solvents ◽  
University Of Missouri ◽  
Synthetic Strategy ◽  
Metal Colloid ◽  
Gold Precursor ◽  
Nanocrystal Synthesis ◽  
Sustainable Media ◽  
Colloid Synthesis

[ACCESS RESTRICTED TO THE UNIVERSITY OF MISSOURI AT REQUEST OF AUTHOR.] Over the past decades, the Green Chemistry and Sustainability concept has aroused researchers to denounce their traditional ways of thinking regarding chemical processes to address the challenges relevant to global environmental concerns. The concept has demonstrated how fundamental scientific methodologies can protect human health and the environment in an economically beneficial manner. In academia and industry, the use of green solvents, such as water, supercritical fluids, ionic liquids (ILs) and deep eutectic solvents (DESs), has then become desirable in chemical processes. In the field of green nanochemistry, ILs and DESs have acquired courtesy as sustainable media for nanomaterials synthesis. There have been attempts to employ such eco-friendly fluids to synthesize, and additionally, control size and shapes of nanomaterials, where the field has been gaining intense interests as the morphology dictates the properties and functionalities of such nanomaterials. This dissertation reports strategies for metal colloidal nanocrystal synthesis in sustainable media and aims to build a foundation for understanding how to tailor eco-friendly IL and DES fluids to control the growth of metal nanocrystals. Chapter 1 explores research reporting strategies used for metal colloid synthesis in ILs and DESs. In Chapter 2, we have developed a strategy to replace a common organic solvent with an IL to prepare monodisperse gold nanoparticles (AuNPs) by a very fast microwave method. The pyrrolidinium IL used in the work demonstrates its capability to be efficiently recovered and reused for carrying out nanoscale synthesis iteratively. The work highlights the incompatibility of imidazolium ILs for the select nanoscale synthetic strategy. For Chapter 3, we have demonstrated a control over nanoparticle size and shape generated at an aqueous-organic interface. We have shown that an interfacial photoreduction leads to the production of spherical and wire-like nanostructures, respectively, when the IL employed involves a coordinated and non-coordinated IL anion, respectively. Next, Chapter 4 has focused on exploitation of a purposefully designed IL-inspired surfactant, acting dually as a reducing and stabilizing agent, for facile and controllable AuNP formation. The reported synthetic method is simple and rapid, using only a gold precursor and the surfactant. Coinage AuNPs can be obtained very fast, while predominantly triangular-shaped AuNPs can also be achieved by tuning parameters, such as the ratio of surfactant to the gold precursor, temperature, implementing a time delay before heating, and an addition of a directing agent. Finally, Chapter 5 outlines zwitterionic deep eutectic solvents (ZDESs) as novel media for metal nanocrystal synthesis, to expand portfolio of available DESs as the field is relatively new compared to that of IL.

scholarly journals Investigation of Base-free Copper-Catalysed Azide–Alkyne Click Cycloadditions (CuAAc) in Natural Deep Eutectic Solvents as Green and Catalytic Reaction Media

2021 ◽  
Author(s):  
Salvatore V. Giofrè ◽  
Matteo Tiecco ◽  
Angelo Ferlazzo ◽  
Roberto Romeo ◽  
Gianluca Ciancaleoni ◽  
...  
Keyword(s):  
Low Temperatures ◽  
Materials Science ◽  
Cycloaddition Reaction ◽  
Deep Eutectic Solvents ◽  
Green Solvents ◽  
Experimental Conditions ◽  
Active Reaction ◽  
Natural Deep Eutectic Solvents ◽  
Catalytic Intermediates ◽  
Reaction Media

<p>The click cycloaddition reaction of azides and alkynes affording 1,2,3-triazoles is a widely used and effective chemical transformation, applied to obtain relevant products in medicine, biology and materials science. In this work, a set of Natural Deep Eutectic Solvents (NADESs) as green and “active” reaction media, has been investigated in the copper-catalysed azide–alkyne cycloaddition reactions (CuAAc). The use of these innovative solvents has shown to improve the reaction effectiveness, giving excellent yields. NADESs proved to be “active” in these transformations for the absence of added bases in all the performed reactions and in several cases, for their reducing capabilities. The reactions outcomes were rationalized by DFT calculations which demonstrated the involvement of H-bonds between DESs and alkynes as well as a stabilization of copper catalytic intermediates. The green experimental conditions, namely the absence of a base, the low temperatures, the lowering of reagents and the possibility of recycling of the green solvents, outline the great potential of NADESs for CuAAc and in general, for green organic synthesis. </p>

Improved stability of salvianolic acid B from Radix Salviae miltiorrhizae in deep eutectic solvents

2016 ◽  
Vol 8 (11) ◽  
pp. 2502-2509 ◽  
Author(s):  
Jue Chen ◽  
Shi-fei Li ◽  
Zhi-feng Yao ◽  
Da-wei Yang ◽  
Li-wei Zhang
Keyword(s):  
Environmentally Friendly ◽  
Deep Eutectic Solvents ◽  
Salvianolic Acid B ◽  
Radix Salviae Miltiorrhizae ◽  
Salvianolic Acid ◽  
Salviae Miltiorrhizae ◽  
Improved Stability ◽  
The Stability

Environmentally friendly deep eutectic solvents were developed for enhancing the stability of salvianolic acid B from Radix Salviae miltiorrhizae.

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