Search Results (18)

Tocols are commonly known as vitamin E, which comprise tocopherols and tocotrienols. Although vegetable oils are natural sources of tocols, deodorizer distillates (DDs) are attractive feedstock due to their potential abundance from oil refining processes and economic price. Deep eutectic solvents (DESs) are a family of neoteric solvents that show promising performance for tocols extraction. Besides their characters occupying the green chemistry concept, this review presents the current research on the potential performances of DESs in extracting tocols selectively and efficiently from DDs. The application of DESs in tocols extraction is presented considering three different ways: mono-phasic, in situ DESs formation, and bi-phasic systems. The basic principles of intermolecular interactions (H-bond, van der Walls bond, and misfit interaction) between DESs or their components with tocols are discussed to understand the mechanism by which DESs selectively extract tocols from the mixture. This is mainly observed to be a function of the intrinsic properties of DESs and/or tocols, which could be beneficial for tuning the appropriate DESs for extracting tocols selectively and effectively under mild operation conditions. This review is expected to provide insight in the potential application of DESs in the extracting of natural compounds with a phenolic structure and also briefly discusses the toxicity of DESs. Full article

Following the successful utilization of various 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ionic liquids (ILs) as effective solvents in the extraction of ethanol, 1-propanol, and 2-propanol from water, we conducted experiments to determine the liquid–liquid equilibria data for the ternary mixture comprising water, ethanol, and 1-decyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([dmim][Tf2N]) at temperatures of 283.2 K, 303.2 K, and 323.2 K under atmospheric pressure. The thermodynamic parameters for both ternary mixtures were calculated using the non-random two-liquid (NRTL) and universal quasichemical (UNIQUAC) models, yielding favorable results across all investigated conditions (rmsd < 0.65%). Subsequently, we explored the efficiency of [dmim][Tf2N] in separating azeotropic mixtures by analyzing the distribution coefficient and selectivity (K₂ and S greater than 1 in all cases, with maximum values of 3.551 and 10.878, respectively). Comparative assessments were made against the performance of various 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ILs and alcohols. The findings underscore the promising capabilities of [dmim][Tf2N] in achieving effective separation, providing valuable insights for potential applications in liquid–liquid extraction processes. Full article

Deep eutectic solvents are an exciting class of designer solvents that are increasingly gaining popularity. Deep eutectic solvents based on amino acids are particularly interesting for biomedical applications due to their potential low toxicity. However, very few have been reported to date, and only one of these has been comprehensively studied, made from a combination of proline and glycerol. Here, we report for the first time a systematic investigation into amino acid-based deep eutectic solvents, with a particular focus on the structural features of amino acids that promote eutectic formation and their influence on viscosity, refractive index, surface tension and thermal behavior. Of the 22 amino acids (and related compounds) examined, only 3 (lysine, arginine and, as previously reported, proline) formed stable homogenous liquids in combination with glycerol or ethylene glycol. For these mixtures, it was found that the second component (glycerol or ethylene glycol) had a much more significant influence on the physical properties than the identity of the amino acid. Most significantly, it was found that far fewer amino acids readily formed deep eutectic solvents than has been generally assumed. This is the first work to systematically characterize deep eutectic solvents based on amino acids and, as such, paves the way for future biomedical applications of these solvents. Full article

Hydroxytyrosol (HT) is a nutraceutical compound, mainly found in the fruit, leaves and waste from the olive oil industry, known for exhibiting one of the highest antioxidant activities among molecules of natural origin. To harness this bioactivity in cosmetics, pharmaceuticals and the food industry, it is essential to modify the hydrophilicity of HT to enhance its compatibility with lipid-based mixtures. This chemical modification must be carried out with high selectivity to avoid compromising its radical scavenging activity. This work presents a highly efficient and selective approach to perform the biocatalytic esterification of free fatty acids (FFAs) of different alkyl chain lengths with HT in a reaction medium based on the SLIL [C₁₂mim][NTf₂]. By using a 1:2 (mol/mol) HT:FFA mixture of substrates, the HT-monoester derivative was obtained up to 77% yield after 2 h at 80 °C. The optimized molar ratio of substrates, combined with the ability to recover the SLIL for further reuse, significantly reduces waste accumulation compared to other reported strategies and results in a more sustainable approach as demonstrated by different green metrics. The antioxidant activity of HT-monoester products was fully maintained with respect to that presented by the natural HT, being stable for at least 3 months at 4 °C, as demonstrated by the DPPH and FRAP antioxidant analysis. Full article

Poly(ethylene terephthalate) (PET) waste accumulation poses significant environmental challenges due to its persistent nature and current management limitations. This study explores the effectiveness of imidazolium-based neoteric solvents [Emim][OAc] and [Bmim][OAc] as catalytic co-solvents in the glycolysis of PET with ethylene glycol (EG). Reaction thermal kinetics showed that both ionic liquids (ILs) significantly enhanced the depolymerization rate of PET compared to traditional methods. The use of [Emim][OAc] offered a lower activation energy of 88.69 kJ·mol⁻¹, thus making the process more energy-efficient. The contribution of key process parameters, including temperature (T), plastic-to-ionic liquid (P/IL) mass ratio, and plastic-to-solvent (P/S) mass ratio, were evaluated by means of a factorial analysis and optimized to achieve the maximum PET conversion for both neoteric solvents. The relevance sequence for both ionic liquids involved the linear factors T and P/S, followed by the interaction factors T×P/S and T×P/IL, with P/IL being the less significant parameter. The optimal conditions, with a predicted conversion of 100%, involved a temperature of 190 °C, with a P/IL of 1:1 and a P/S of 1:2.5, regardless of the IL used as the catalytic co-solvent. Full article

The extraction of bioactive compounds of pharmaceutical interest from natural sources has been significantly explored in recent decades. However, the extraction techniques used were not very efficient in terms of time and energy consumption; additionally, the solvents used for the extraction were harmful for the environment. To improve the environmental impact of the extractions and at the same time increase the extraction yields, several new extraction techniques were developed. Among the most used ones are ultrasound-assisted extraction and microwave-assisted extraction. These extraction techniques increased the yield and selectivity of the extraction in a smaller amount of time with a decrease in energy consumption. Nevertheless, a high volume of organic solvents was still used for the extraction, causing a subsequent environmental problem. Neoteric solvents appeared as green alternatives to organic solvents. Among the neoteric solvents, deep eutectic solvents were evidenced to be one of the best alternatives to organic solvents due to their intrinsic characteristics. These solvents are considered green solvents because they are made up of natural compounds such as sugars, amino acids, and carboxylic acids having low toxicity and high degradability. In addition, they are simple to prepare, with an atomic economy of 100%, with attractive physicochemical properties. Furthermore, the huge number of compounds that can be used to synthesize these solvents make them very useful in the extraction of bioactive compounds since they can be tailored to be selective towards a specific component or class of components. The main aim of this paper is to give a comprehensive review which describes the main properties, characteristics, and production methods of deep eutectic solvents as well as its application to extract from natural sources bioactive compounds with pharmaceutical interest. Additionally, an overview of the more recent and sustainable extraction techniques is also given. Full article

Microalgae, as some of the oldest life forms on Earth, are of significant interest to industry and in terms of environmental policies, due to their ability to perform photosynthesis and consume atmospheric carbon dioxide. Moreover, they contain a wide variety of value-added compounds such as amino acids and proteins, carbohydrates, and fatty acids, which can be exploited in multiple fields like medicine, cosmetics, nutritional supplements, and for the production of biodiesel. In this article, Nannochloropsis gaditana, a type of microalgae that inhabits both fresh and salt water, is studied for fatty acid recovery using deep eutectic solvents (DES). This microalgae species is a natural source of eicosapentaenoic acid (EPA), an omega-3 compound that is commonly used in the nutritional industry. There are numerous extraction techniques and pretreatments to obtain these compounds. In this work, DES are studied as extractive agents due to their advantages as neoteric solvents. Specifically, this work focuses on an assessment of the effect of the composition of DES on the extraction yield of fatty acids from microalgae. Several DES compositions based on choline chloride, ethylene glycol, and fructose are studied to analyze the influence of water content in these phases. The results show that water content significantly influences recovery yields. The DES with higher extractive capacity were those based on choline chloride, ethylene glycol, and water at a molar ratio of 1:2:2. This composition offered 48.7% of the yield obtained with a conventional solvent like methanol for the recovery of EPA (11.2 mg/g microalgae). Furthermore, the choline chloride-fructose-based DES shows the capability of selective extractions of fatty acids with low carbon content—choline chloride:fructose:water (molar ratio 2:1:2) can extract 0.14 mg of decanoic acid/g of microalgae, indicating that this DES composition can recover 35.7% more decanoic acid in comparison to methanol. Full article

Ionic liquids are a family of liquids that are composed entirely of ions and usually have melting points lower than 100 °C. Extensive research, along with the ever-growing interest of the scientific community, allowed for the development of a multitude of ionic liquids with low melting points. Such compounds are considered neoteric materials as well as ideal, custom-made solvents for a variety of different chemical transformations. In this regard, the importance of phase transfer catalysis is evident in a diversity of substrates and reactions. The use of phase transfer catalysts allows the reaction to proceed, facilitating the transfer of otherwise insoluble reactants to the desired phase. Recent scientific advances led to the emergence of ionic liquids, which are excellent candidates as phase transfer catalysts. The inherent fine-tuning capability of these molecules, along with the potential of phase transfer catalytic reactions, epitomize the sustainable aspect of this field of research. Herein, a cohesive report of such applications will be presented, including the period from the last decade of the 20th century up to date. Full article

The recovery of plant mineral nutrients from the bio-based value chains is essential for a sustainable, circular bioeconomy, wherein resources are (re)used sustainably. The widest used approach is to recover plant nutrients on the last stage of biomass utilization processes—e.g., from ash, wastewater, or anaerobic digestate. The best approach is to recover mineral nutrients from the initial stages of biomass biorefinery, especially during biomass pre-treatments. Our paper aims to evaluate the nutrient recovery solutions from a trans-sectorial perspective, including biomass processing and the agricultural use of recovered nutrients. Several solutions integrated with the biomass pre-treatment stage, such as leaching/bioleaching, recovery from pre-treatment neoteric solvents, ionic liquids (ILs), and deep eutectic solvents (DESs) or integrated with hydrothermal treatments are discussed. Reducing mineral contents on silicon, phosphorus, and nitrogen biomass before the core biorefinery processes improves processability and yield and reduces corrosion and fouling effects. The recovered minerals are used as bio-based fertilizers or as silica-based plant biostimulants, with economic and environmental benefits. Full article

Ionic liquids (ILs) and deep eutectic solvents (DESs) are the two most widely used neoteric solvents. Recently, our group described how the simple addition of acetic acid (AcOH) to 1-Ethyl-3-methylimidazolium chloride (EMIMCl) could promote the transition from the original IL to an eutectic mixture of EMIMCl and AcOH. Herein, we studied how cellulose regeneration and EMIMCl recovery from EMIMCl solutions of cellulose could be benefited by the significant differences existing between EMIMCl- and EMIMCl·AcOH-based mixtures and the easy switching from one to the other. Finally, we also demonstrated that the transition could also be accomplished by addition of acetic anhydride and water so that the process could be eventually useful for the achievement of highly acetylated cellulose. Full article

The incessant generation of toxic waste and the growing concern over the environment have led the scientific community to delve into the search for more sustainable systems. In this regard, the application of deep eutectic solvents (DESs) has become one of the main strategies in green chemistry. These solvents have emerged as a promising alternative to conventional toxic solvents and even to the well-known ionic liquids. Their unique properties, components availability, and easy preparation, among others, have led to a new trend within the scientific community and industry, based on the use of these up-and-coming solvents not only in science but also in quotidian life. Among the areas that have benefited from the advantages of DESs is analytical chemistry, in which they have been largely used for sample preparation, including the extraction and determination of organic and inorganic compounds from environmental samples. The considerable number of applications developed in the last year in this field and the increasing generation of new data necessitate the continuous updating of the literature. This review pretends to compile the most relevant applications of DESs in environmental analysis and critically discuss them to provide a global vision about the advantages and drawbacks/limitations of these neoteric solvents in the area of environmental analysis. Full article

The aim of this study was to synthesize, characterize, and evaluate neoteric imine compounds for antimicrobial activity and hemocompatibility. Four compounds were synthesized using 3-thiophene carboxaldehyde, ethanol, amine, and acetic acid. The compounds were characterized using nuclear magnetic resonance (NMR) spectroscopy, Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and powder X-ray diffraction (PXRD). A solubility study was conducted with various solvents and surfactants at 40 °C. An in vitro antimicrobial assay was performed against bacterial and fungal strains to determine the zone of inhibition and minimum inhibitory concentrations. Finally, an in vitro hemolysis study was conducted using rat erythrocytes. The structure of the compounds was confirmed by NMR, FTIR corroborated their functional group attributes, DSC determined their enthalpies of fusion and fusion temperatures, and PXRD confirmed their crystalline nature. These compounds were water-insoluble but soluble in chloroform, with a maximum solubility of ~80 mg/mL. The antimicrobial assay suggested that two of the products exerted potent activities against C. albicans and several bacterial strains. Finally, hemolysis analysis excluded the possibility of hemolysis at the assessed concentrations. In conclusion, two of the novel imine compounds showed promise as antimicrobial agents to control local and systemic microbial infections in a suitable dosage form. Full article

Throughout numerous research works on biomacromolecules, several breakthrough innovations have occurred in the field of biomacromolecule processing. Remarkable improvements have been made so far to address the problems associated with biomacromolecule processing technologies in terms of enhancing the efficiency of the processes. Green technology broadly focuses on the search for new techno-economic systems to replace the conventional systems which exhibit pernicious consequences for the environment and the health of organisms. The strategy practiced popularly is the use of alternate solvent systems, replacing the conventional toxic, volatile, and harsh organic solvents to prevent denaturation, biotransformation, enzyme activity loss, and degradation of biomacromolecules. Ionic liquids (ILs) and deep eutectic solvents (DESs) are emerging as greener alternatives over the past two decades and there has been an exponential increase in reports in the literature. The utility of neoteric solvents in biomacromolecule treatment may be envisaged for industrial processes in the near future. The current state of the art regarding the recent developments made over the past few years using neoteric solvents has been reviewed in this article. The recent scientific developments regarding the use of these neoteric solvents, especially ILs and DESs, for processes such as solubilization, extraction, and functionalization of biomacromolecules, especially proteins and DNA, have been addressed in this article. This review may be beneficial for designing novel and selective methodologies for the processing of biomacromolecules, opening doors for better material research in areas such as biotechnology and biological sciences. Full article