The role of green chemistry in the transformation of agro-industrial wastes for health and environment: a review.

[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.

随着绿色化学的发展,开发和应用符合绿色化学要求的溶剂和方法备受关注。作为离子液体类似物,低共熔溶剂(deep eutectic solvent, DES)是通过氢键受体(hydrogen bond acceptor, HBA)和氢键供体(hydrogen bond donator, HBD)的氢键作用而形成的一种混合物,具有环境友好、制备简单、成本低、可生物降解等优点,在很多领域均有越来越广泛的应用。DES可以从不同样品中萃取和分离不同的目标化合物,其作为萃取溶剂具有独特的优势,可以获得较高的萃取效率且样品基质对分析过程的影响较小。在分散液液微萃取(dispersive liquid-liquid micro-extraction, DLLME)程序中,DES可以萃取复杂基质中的残留药物、金属离子和生物活性成分;与传统的萃取方法相比,该方法具有对有机试剂需求少,萃取效率更高等明显优势。而且,在DLLME中加入DES作为分散剂,能够加速萃取剂在样品溶液中的扩散,具有小型化、成本低等优点。相比于传统分散剂甲醇、乙腈的高挥发性、易燃性,DES的高稳定性、低毒性使其在绿色化学领域中更具有优势,应用更广。因此,DES与DLLME的结合近年来发展迅速。不仅如此,DES与固相萃取联合应用也具有广泛的应用前景,在与固相萃取小柱和搅拌棒联合应用时,DES可以作为洗脱剂,氢键供体及氢键给体的用量之比是洗脱效率的重要考察因素之一。在与磁性材料联用时,DES能与磁性多壁碳纳米管、磁性氧化石墨烯等纳米复合材料结合,通过氢键、π-π作用力和静电作用力等特异性吸附目标分析物。并且能够参与磁性凝胶和分子印迹聚合物的合成,推动磁性材料向绿色化学的方向发展,进一步拓展DES的应用。作为一类新兴的绿色溶剂,DES在化合物的萃取分离技术方面受到广泛关注,在不同的萃取技术中扮演了不同的角色,并表现出良好的性能,因此逐渐成为绿色化学领域的研究重点。该文整合了DES在萃取分离技术中的研究进展,介绍了DES的制备、性质和分类,对DES在DLLME和固相萃取中的应用进行了总结和归类,并展望了DES在萃取分离技术中的应用前景,为DES未来的应用提供参考。

Development of deep eutectic solvents for sustainable chemistry

Hydrophobic deep eutectic solvents: the new generation of green solvents for diversified and colorful applications in green chemistry

Superlong supercooling solvents (SSSs): Alternative green solvents to ionic liquids and deep eutectic solvents for lithium-ion batteries recycling

Forward-looking, sustainable, and green approaches in analytical chemistry have become a significant topic worldwide. This has attracted considerable attention from scientists in improving methods for analyzing a broad area of analytes and samples, such as pharmaceuticals in biological matrices. These enhancements generally adhere to principles of Green Chemistry (GC) and Green Analytical Chemistry (GAC). To align with these principles, utilizing green materials and solvents, such as deep eutectic solvents (DESs) and ionic liquids (ILs), has proven to be highly effective in making analytical chemistry approaches more environmentally friendly. Building on these principles, we consider specific applications of green solvents in microextraction techniques by analyzing published studies, which have focused on developing solid-phase and liquid-phase microextraction of pharmaceuticals, using DESs and ILs in biological samples. Here, we explored the applicability of these green solvents in microextraction approaches and examined how the analytical results might be affected. We also focused on the different types of DESs and ILs, their characteristics, their ecotoxicity and biodegradability. Furthermore, we examined the advantages and disadvantages of these solvents, addressing both aspects common to all microextraction methods and those specific to individual approaches. Finally, we highlighted the current challenges in this field and outlined future perspectives to overcome them.

Chapter 4 - Green solvents for drug synthesis

In the last two decades, Ionic Liquids (ILs) have attracted considerable attention in many fields of scientific research. ILs have drawn an increasing interest due to their unique physical and chemical properties that showed a great potential as an alternative media in many potential applications. ILs are defined as low melting point, lower than 100 °C, salts consisting of organic cations and organic/inorganic anions both of which are large ions and held together by electrostatic interactions. ILs has very low vapor pressure, non-flammable, tunable and can dissolve both polar and non-polar compounds. Owing to their low vapor pressure ILs were qualified as green solvents. However, the green affiliation of ILs is now contested by many research groups. The conventional technology used for oil extraction from oilseeds is by solvent extraction. In solvent extraction, n-hexane is used as a solvent for its attributes such as simple recovery, non-polar nature, low latent heat of vaporization (330 kJ/kg) and high selectivity to solvents. However, usage of hexane as a solvent has lead to several repercussions such as air pollution, toxicity and harmfulness that prompted to look for alternative options.The hazardous toxicity and the very poor biodegradability of many ILs have been reported in the literature. ILs with high purity is also required since impurities, even in trace amounts, affect their physical properties. These drawbacks together with the high price of common ILs delayed their industrial applications and new concepts were strongly needed in order to utilize these systems in a more rational way. To overcome these drawbacks, a new generation of solvents, named Deep Eutectic Solvents (DES), has emerged as alternative to ILs in many applications. Formation of these DESs can be obtained by simply mixing together two or more components that can be chosen to be cheap, renewable and biodegradable. These compounds are capable of forming a eutectic mixture with a melting point lower than that of each individual component. DESs are generally liquid at temperatures lower than 100 °C. Many DESs have similar physical-chemical properties to those of ILs, while being much cheaper and environmentally friendlier. Owing to these advantages, there is now of growing interest in DESs in many fields of research. DESs are chemically tailorable solvents since they can be designed by properly combining various quaternary ammonium or phosphonium salts with different Hydrogen Bond Donors (HBD) or complexing agents. Hence, task-specific DESs with different physical-chemical properties can be prepared. It should also be noted that although components of DESs are potentially reactive chemicals, their auto-association by a hydrogen bond drastically limits their reactivity, allowing their use in many fields of research. In this work, we discuss the application of both ILs and DESs in petroleum refining and petrochemical processes. Examples include, but are not limited to, separation of aromatics, de-sulfurization, de-nitrification and carbon dioxide capture.

New guidelines for testing “Deep eutectic solvents” toxicity and their effects on the environment and living beings

Deep eutectic solvents microbial toxicity: Current state of art and critical evaluation of testing methods

Global warming is a critical issue resulting partly from increasing carbon dioxide emissions. Technologies have been developed to capture carbon dioxide followed by storage or utilization, yet techniques are limited by the use of toxic solvents and the generation of harmful by-products. Research in green chemistry has designed green solvents which are non-toxic, efficient and environmentally friendly. Here we review green solvents employed for carbon capture, with emphasis on ionic liquids, deep eutectic solvents and liquid polymers. Solvent performance depends on temperature, density and viscosity. Deep eutectic solvents appear as the most advanced solvents with capacities reaching up to 4.292 g CO2 per g of solvent. Ionic liquids have shown CO2 uptakes of 4.72 mol of CO2/mol of solvent, but are less efficient on average. Liquid polymers display capacities of up to 1.357 mol of CO2/mol of solvent.

A new era of chitin synthesis and dissolution using deep eutectic solvents- comparison with ionic liquids

<p>Pemanasan global akibat emisi gas rumah kaca, terutama karbon dioksida (CO<sub>2</sub>), memiliki pengaruh yang signifikan terhadap perubahan iklim dan telah menjadi isu penting dalam beberapa tahun terakhir. Penangkapan dan pemanfaatan CO<sub>2</sub> atau CO<sub>2</sub> <em>capture and utilization</em> (CCU) adalah strategi yang efektif untuk mengurangi pemanasan global. Makalah ini bertujuan untuk memberikan gambaran singkat proses penangkapan CO<sub>2</sub> dengan memanfaatkan cairan ionik (<em>ionic liquid</em>, IL). IL adalah jenis garam yang terdiri dari kation organik dan anion organik atau anorganik yang memiliki beberapa keunggulan, di antaranya volatilitas yang rendah, stabilitas termal yang cukup baik, tidak mudah korosif, laju degradasi yang rendah, dan biaya regenerasi yang rendah. Kombinasi kation-anion yang tepat membuat IL dapat digunakan sebagai pelarut untuk proses penangkapan CO<sub>2</sub> menggantikan pelarut konvensional berbasis amina. Dalam perkembangan selanjutnya, generasi baru IL fungsional (IL berbasis basa kuat dan asam amino) dan <em>deep eutectic solvent</em> (DES) telah diperkenalkan sebagai larutan pengganti IL murni (IL konvensional) dengan keunggulan kapasitas penyerapan CO<sub>2</sub> yang lebih besar, mudah terurai secara alami (<em>biodegradable</em>), mudah berinteraksi dengan jaringan hidup, tidak menimbulkan toksisitas (biokompatibel), dan mudah diproduksi dalam skala besar dengan biaya relatif rendah. Selain itu, dengan mempertimbangkan biokompatibilitas DES, pengembangan DES dengan mempertimbangkan aspek biologis menjadi terobosan baru yang menjanjikan sebagai bahan ramah lingkungan. Dalam hal ini DES menyerap CO<sub>2</sub> dari gas buang dan kemudian menyediakannya sebagai sumber nutrisi bagi mikroalga.</p><p><strong>Ionic Liquid as CO<sub>2</sub> Absorption. </strong>An increase in global warming as an impact of greenhouse gases, particularly carbon dioxide (CO<sub>2</sub>), has become an important issue in recent years. CO<sub>2</sub> capture and utilization (CCU) are the effective strategy to mitigate global warming. This study briefly described the CO<sub>2</sub> capture process using ionic liquid (IL). IL is a type of salt consisting of organic cations and organic or inorganic anions. IL as a solution in the CO<sub>2</sub> capture process has several advantages, including low volatility, good thermal stability, non-corrosive, low degradation, and low regeneration costs. Using the proper cation and anion, IL acts as an effective solvent for CO<sub>2</sub> capture, replacing amine. In subsequent developments, a new generation of functional IL (strong base and amino acid-based IL) and deep eutectic solvent (DES) has been introduced as a substitute for pure IL (conventional IL) with the advantages of more excellent CO<sub>2</sub> absorption, biodegradable, easy to interact with live tissue, non-toxicity, biocompatible, and easy to produce on a large scale with relatively low cost. In addition, taking into account the biocompatibility of DES, the development of DES by considering the biological aspects is a promising alternative as an environmentally friendly material. In this case, DES absorbs CO<sub>2</sub> from exhaust gases and provides it as a source of nutrition for microalgae.</p>

Green Chemistry plays a more and more important role in implementing rules of sustainable development to prevent environmental pollution caused by technological processes, while simultaneously increasing the production yield. Ionic liquids (ILs) and deep eutectic solvents (DESs) constitute a very broad group of substances. Apart from many imperfections, ILs and DESs have been the most promising discoveries in the world of Green Chemistry in recent years. The main advantage of ILs is their unique physicochemical properties-they are very desirable from the technological point of view, but apart from these benefits, ILs appear to be highly toxic towards organisms from different trophic levels. DES areas of usage are very spread, because they cover organic synthesis, extraction processes, electrochemistry, enzymatic reactions and many others. Moreover, DESs seem to be a less toxic alternative to ionic liquids. New possibilities of applications and future development trends are sought and presented, including such important solutions of life branches as pharmaceuticals' production and medicine.

A comparative study of thermophysical properties between choline chloride-based deep eutectic solvents and imidazolium-based ionic liquids