Deep Eutectic Solvents and Multicomponent Reactions: Two Convergent Items to Green Chemistry Strategies.
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ABSTRACT:
SUBMITTER: Calvo-Flores FG
PROVIDER: S-EPMC8369850 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:Hydroxymethylfurfural (5-HMF) is a key platform chemical, essential for the production of other chemicals, as well as fuels. Despite its importance, the production methods applied so far still lack in sustainability. In this work, acidic deep eutectic solvents (DES), acting both as solvent and catalyst, were studied for the conversion of fructose into 5-HMF using microwave-assisted reactions. These solvents were screened and optimized by varying the hydrogen bond donor (HBD) and hydrogen bond acceptor (HBA). The bio-based solvent γ-valerolactone (GVL) was also applied as additive, leading to a boost in 5-HMF yield. Then, a response surface methodology was applied to further optimize operating conditions, such as reaction time, temperature and wt.% of added GVL. The highest 5-HMF yield attained, after optimization, was 82.4% at 130 °C, in 4 min of reaction time and with the addition of 10 wt.% of GVL. Moreover, a process for 5-HMF recovery and DES reuse was developed through the use of the bio-based solvent 2-methyltetrahydrofuran (2-Me-THF), allowing at least three cycles of 5-HMF production with minimal yield losses, while maintaining the purity of the isolated 5-HMF and the efficacy of the reaction media.
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Project description:Deep eutectic solvents (DESs) are eutectic mixtures of salts and hydrogen bond donors with melting points low enough to be used as solvents. DESs have proved to be a good alternative to traditional organic solvents and ionic liquids (ILs) in many biocatalytic processes. Apart from the benign characteristics similar to those of ILs (e.g., low volatility, low inflammability and low melting point), DESs have their unique merits of easy preparation and low cost owing to their renewable and available raw materials. To better apply such solvents in green and sustainable chemistry, this review firstly describes some basic properties, mainly the toxicity and biodegradability of DESs. Secondly, it presents several valuable applications of DES as solvent/co-solvent in biocatalytic reactions, such as lipase-catalyzed transesterification and ester hydrolysis reactions. The roles, serving as extractive reagent for an enzymatic product and pretreatment solvent of enzymatic biomass hydrolysis, are also discussed. Further understanding how DESs affect biocatalytic reaction will facilitate the design of novel solvents and contribute to the discovery of new reactions in these solvents.
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Project description:Agri-food industries generate a large amount of waste that offers great revalorization opportunities within the circular economy framework. In recent years, new methodologies for the extraction of compounds with more eco-friendly solvents have been developed, such as the case of natural deep eutectic solvents (NADES). In this study, a methodology for extracting phenolic compounds from olive tree leaves using NADES has been optimized. The conditions established as the optimal rely on a solvent composed of choline chloride and glycerol at a molar ratio of 1:5 with 30% water. The extraction was carried out at 80 °C for 2 h with constant agitation. The extracts obtained have been analyzed by high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) in MRM mode. The comparison with conventional ethanol/water extraction has shown that NADES, a more environmentally friendly alternative, has improved extraction efficiency. The main polyphenols identified in the NADES extract were Luteolin-7-O-glucoside, Oleuropein, 3-Hydroxytyrosol, Rutin, and Luteolin at the concentrations of 262, 173, 129, 34, and 29 mg kg-1 fresh weight, respectively.
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Project description:Deep eutectic solvents (DESs) are an emerging class of modern, often "green" solvents with unique properties. Recently, a deep eutectic system based on amphiphilic surfactant N-alkyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (C12 & C14 sulfobetaine) and (1S)-(+)-10-camphor-sulfonic acid in the molar ratio 1:1.5 has been reported. Nanostructuring can be expected in this DES due to the nature of the components. In this work, we have investigated the native nanostructure in the DES comprising C12-C18 alkyl chain sulfobetaines with camphor sulfonic acid and how it interacts with polar and nonpolar species, water and dodecane, respectively, using small angle neutron scattering. By using contrast variation to highlight the relative position of the solvent components and additives, we can resolve the structure of the solvent and how it changes upon interaction with water and dodecane. Scattering from the neat DES shows structures corresponding to the self-assembly of sulfobetaines; the size of the structure increases as the alkyl chain length of the sulfobetaines increases. Water and dodecane interact, respectively, with the hydrophilic and hydrophobic moieties in the DES structure, primarily the sulfobetaine, thereby swelling and solvating the entire structure. The extent of the shift of the peak position, and the swelling, depend on concentration of the additive. The solution phase organization and the interaction of polar and nonpolar species as observed here, have the potential to affect the ordering of inorganic or polymeric materials grown in such solvents, paving new avenues for templating applications.
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