Pressurized techniques are straightforward for high-scale applications and highly controllable, which seems an excellent strategy for recovering unstable natural compounds. In this work, the main ...advance was the development of a platform based on the pressurized liquid extraction coupled in-line with a solid-phase extraction step (PLE-SPE) combined with the use of eutectic mixtures as solvents to promote an efficient extraction and purification of natural pigments from food wastes. Eutectic mixtures, conventionally known as (deep) eutectic solvents - (D)ES, are combinations of two or more substances with a lower melting point than any of their components. (D)ES are often referred as "green solvents" because they can potentially be more environmentally friendly than other solvents, especially volatile organic solvents (VOSs). Overall, (D)ES have the potential to contribute to the achievement of several of the SDGs (especially 3, 13, and 14) through their positive impacts on health, environment, and sustainable production and consumption practices. Thus, in this work, (D)ES were used as solvents to valorize Brazilian berry waste (
Plinia cauliflora
). Anthocyanins are the biomass's main compounds of commercial interest, mainly for food and cosmetic applications. However, there are several technological issues regarding color control due to their high sensitivity to light, heat, oxygen, and pH variations. Thus, the data achieved in this work highlighted the high efficiency and low environmental footprint of the PLE-SPE-(D)ES platform developed. The success of the downstream process here developed was proved by the high extraction efficiency and the purity level of the anthocyanins obtained. Besides, thermal stability analysis was evaluated, demonstrating that (D)ES are not only solvents but also stabilizing agents, improving the shelf-life of the extracted colorants.
A PLE-SPE extraction process for the anthocyanins from Jabuticaba wastes was developed using an eutectic mixture, this acting simultaneously as solvent and stabilizing agent.
This work evaluates the potential use of 2-hydroxy ethylammonium-based protic ionic liquids (PILs) for dissolving the major lignocellulosic biopolymers such as cellulose, xylose and lignin. Three ...PILs, 2-hydroxy ethylammonium formate (2-HEAF), 2-hydroxy ethylammonium acetate (2-HEAA) and 2-hydroxy ethylammonium propionate 2-HEAPr, were synthesized and characterized (viscosity, density and conductivity). A small amount of biopolymer was added to the PILs; the biopolymers’ dissolution curves were determined from 30 °C up to 100 °C on these solvents using a hot stage coupled to an optical microscope. The results show that while xylose and lignin could be dissolved by the PILs, cellulose could not, and also that 2-HEAF—which presented the higher ionicity—was the most appropriate PIL among those tested to dissolve these biopolymers (xylose and lignin). They also show that lignin dissolution is faster when an anion with a short alkyl carbon chain is used and that higher heating rates require a somewhat higher temperature to achieve full dissolution.
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EMUNI, FIS, FZAB, GEOZS, GIS, IJS, IMTLJ, KILJ, KISLJ, MFDPS, NLZOH, NUK, OBVAL, OILJ, PNG, SAZU, SBCE, SBJE, SBMB, SBNM, UKNU, UL, UM, UPUK, VKSCE, ZAGLJ
Certain organic superbase ionic liquids (ILs) have shown good cellulose dissolution and fiber regeneration performance, allowing us to obtain high-quality textile fibers. However, there is a lack ...regarding the IL recovery from the spinning bath and its purification, which is essential for the economic viability of the process. Aiming to understand methods to separate ILs from water for reuse/recycle, the use of pressure-driven membrane processes to recycle ionic liquids from aqueous solution was investigated. The recovery of two superbase ILs, 7-methyl-1,5,7-triazabicyclo4.4.0dec-5-enium acetate, mTBDHOAc, and 5-methyl-1,5,7-triaza-bicyclo4.3.0non-6-enium acetate, mTBNHOAc, were studied using different types of membranes (microfiltration, ultrafiltration, nanofiltration, and reverse osmosis, RO). Additionally, pressure, IL concentration, temperature, and multicycle effect were evaluated. Significant retentions (>45%) were obtained for the nanofiltration and RO membranes (NF270-NF and BW30LE-RO). The increase in pressure and temperature resulted in an increase in volumetric flux and a decrease in IL retention. On the other hand, IL concentration decreased the volumetric flow and rejection. For the serial filtration tests, a three-fold ionic liquid concentration was achieved, for a maximum concentration of 14 wt % of the ionic liquid. The membrane filtration methodology proved to be an efficient technique for carrying out the preconcentration of the IL from dilute solutions.
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•Combining ethanol and water as a safe mobile phase to UPLC-analysis of anthocyanins.•Fast, green, and universal method to analyze anthocyanins.•Identification of 53 anthocyanins from ...9 foods.•The developed method achieved a high green analytical score.
This work developed a universal UPLC-PDA method based on safe reagents to analyze anthocyanins from different foods. Nine foods were studied by the developed chromatographic method, which was constructed using a solid core C18 column and a binary mobile phase composed of (A) water (0.25 molcitric acid.Lsolvent−1), and (B) ethanol. A total running time of 6 min was obtained, the faster comprehensive method for anthocyanins analysis. Mass spectrometry analysis was employed to identify a comprehensive set of 53 anthocyanins comprising glycosylated and acylated cyanidin, pelargonidin, malvidin, peonidin, petunidin, and delphinidin derivatives. Cyanidin-3-O-glucoside (m/z+ 449) and cyanidin-3-O-rutinoside (m/z+ 595) were used as standards to validate the accuracy of the developed method. The analytical parameters were evaluated, including intra-day and inter-day precision, robustness, repeatability, retention factor (k), resolution, and peak symmetry factor. The current method demonstrated excellent chromatographic resolution, making it a powerful tool for analyzing anthocyanins pigments.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lignin stands as a promising raw material to produce commodities and specialty chemicals, yet its poor solubility remains a big challenge. Recently, deep eutectic solvents (DES) have been proposed as ...sustainable solvents with high potential to dissolve and valorize lignin. In the present study, the ability of DES based on cholinium chloride (ChCl) combined with alcohols and carboxylic acids as hydrogen bond donors (HBDs) to dissolve kraft lignin and to change its chemical structure was examined. The influence of the chemical nature of HBDs, water content, and HBD:hydrogen bond acceptor (HBA) molar ratio on the solubility of kraft lignin in DES was studied (313.15 K). The kraft lignin solubility was enhanced by increasing both the HBD’s carbon chain length and the molar ratio, with ChCl:HEXA (1,6-hexanediol) and ChCl:MaleA (maleic acid) being the best studied solvents for kraft lignin dissolution, while the addition of water was a negative factor. The thermal treatments (393.15 K) of kraft lignin show that carboxylic acid-based DES promote chemical modifications to kraft lignin, including the disruption of several C–O covalent type bonds (e.g., β-O-4, α-O-4 and α-O-α), while alcohol-based DES were found to be nonderivatizing solvents maintaining the lignin chemical structure. These results show the versatility of DES, which, depending on their chemical nature, may offer distinct strategies for lignin valorization.
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In this study, the potential of alkanolammonium-based protic ionic liquid (PIL) aqueous solutions as solvents of Kraft lignin was evaluated. The results showed that the PILs’ anion plays a key role ...in lignin dissolution, while the cation plays a secondary role. The presence of extra hydroxyl groups in the anion structure negatively affects lignin solubility, while the increase of the cation alkyl chain favors this process. Using mechanical agitation, all tested PILs required 8 h to reach saturation, except for lactate-based PILs (at least 24 h). The efficiency of lignin dissolution was improved with ultrasounds achieving saturation in less than 4 h. Finally, the recyclability of two PILs was herein demonstrated for at least three cycles. Tris(2-hydroxyethyl)ammonium lactate presented the best ability to dissolve Kraft lignin (>47 wt %) among the tested PILs. This result shows the capacity of PILs as excellent media to dissolve lignin.
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In this study, an acidic deep eutectic solvent (DES) was used as a benign solvent to valorise technical lignins by breaking down their structure into value-added aromatic compounds. The action of an ...acidic DES composed of cholinium chloride (ChCl) and oxalic acid (Oxa), at a molar ratio of 1 : 1, towards the depolymerisation of Kraft and Organosolv lignins (KL and OL) was studied under mild conditions (80 °C, for 1 to 6 h). Furthermore, the addition of hydrogen peroxide (H
2
O
2
) or sulfuric acid (H
2
SO
4
) as a co-catalyst was also performed. The obtained data showed maximum yields between 26.1 wt% and 27.8 wt% of lignin depolymerisation products after KL and OL breakdown. Moreover, the profile of depolymerisation products was distinct between the examined lignins as well as between acidic (ChCl : Oxa and ChCl : Oxa/H
2
SO
4
) and acidic oxidative treatments (ChCl : Oxa/H
2
O
2
). The acidic treatments of KL favoured the formation of syringol and acetosyringone, while vanillic and syringic acids were the main products in the acidic treatments of OL. On the other hand, the presence of H
2
O
2
in the DES enabled the ability to promote the electrophilic substitutions of chloride from ChCl in the aromatic ring of lignin monomers. After depolymerisation, the regenerated lignin samples presented a different molecular weight, while FT-IR data showed structural changes, including esterification with oxalic acid and formation of phenolic groups as a consequence of aryl ether bond breakdown. The insights gained in this study provide a better understanding on lignin depolymerisation with a DES (in the presence and absence of co-catalysts) and envisage process integration through the production of lignin monomers (and oligomers) combined with the functionalisation of regenerated lignin.
The valorisation of technical lignins by conversion is herein demonstrated using an acidic deep eutectic solvent in the absence or presence of a co-catalyst (H
2
SO
4
or H
2
O
2
).
Synopsis. Filtration of different ILs aqueous solution using membrane technology is herein demonstrated to highlight the influence of cation/anion in recovering ILs from aqueous solutions.
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•Purification of 11 different ILs using nanofiltration and reverse osmosis.•Effect of ionic liquid cation and anion in membrane filtration.•The Donnan exclusion mechanism was the limiting factor in reverse osmosis membrane.•The sieving and adsorption of IL within the membrane limited the nanofiltration.
Ionic liquids (ILs) have great potential as solvents and catalysts in the most diverse areas of the chemical industry. However, the need for a process that allows the recycling and purification of ILs in an efficient and economically viable manner is restricting the practical application of these solvents. The recycling processes most used to recover ILs are distillation and evaporation, followed by extraction and crystallization. However, most of these processes demand high energy consumption, or temperatures that may compromise the structural and chemical stability of the ILs. This work focuses on understanding the separation of ionic liquid from aqueous solution using membranes, a technique widely used in industry. The separation of eleven ILs ((C4mimAOc, C4mimSCN, C4mimCF3SO3, C4mimCF3CO2, C4mimCl, C8mimCl, P4444Cl, N4444Cl, C4mpipCl, C4mpyrCl and C4-2-mpyCl) was studied using a nanofiltration (NF270) and a reverse osmosis (BW30LE) membrane. The influence of cation and anion, pressure, IL concentration, and temperature, on the separation of ILs, was evaluated. The Donnan exclusion mechanism was found to be the limiting factor for the reverse osmosis, while the combination of concentration polarization and sieving mechanism was the limiting factor for nanofiltration membrane. The increase of temperature and pressure leads to an increase in the volumetric flux at the cost of a decrease of the IL retention. On the other hand, the increase in the concentration of the IL solution resulted in an increase in the osmotic pressure and, consequently, a decrease in the volumetric flow and a decrease in the rejection of the IL.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Superbase-based ionic liquids 7-methyl-1,5,7-triazabicyclo4.4.0dec‑5-enium acetate, mTBDHOAc, and 5-methyl-1,5,7-triaza-bicyclo4.3.0non-6-enium acetate, mTBNHOAc, are good candidates to produce high ...performance cellulose fibres while presenting much easy spinnability and good recyclability, than the state-of-the-art ionic liquids. Nevertheless, the recovery of the IL from the aqueous spinning bath and its purification, which are both an economical and environmental necessity, are important aspects that are still not solved. Aiming to gather knowledge to recover and recycle superbase-ILs, the main goal of this work is the physicochemical characterization of the binary systems water + mTBDHOAc or mTBNHOAc. Measurements performed include solid-liquid equilibria, vapor-liquid equilibria, water activity, Kamlet−Taft solvatochromic parameters, densities, and viscosities. An experimental screening on possible hydrophobic extractants for the recuperation of the ionic liquids from aqueous solution was performed. Using butanol, an extraction efficiency of 37% for mTBDHOAc was achieved. Better extraction efficiencies were achieved with chlorinated solvents, however, they seem to react with the ILs anion.
Synopsis. The physicochemical characterization of mixtures of ILs and water is herein demonstrated to highlight the challenges in recovering hydrophilic ILs from aqueous solutions. Display omitted
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Lignin holds significant potential as a feedstock for generating valuable aromatic compounds, fuels, and functional materials. However, achieving this potential requires the development of effective ...dissolution methods. Previous works have demonstrated the remarkable capability of hydrotropes to enhance the aqueous solubility of lignin, an amphiphilic macromolecule. Notably, deep eutectic solvents (DESs) have exhibited hydrotropic behavior, significantly increasing the aqueous solubility of hydrophobic solutes, making them attractive options for lignin dissolution. This study aimed at exploring the influence of hydrogen bond acceptors (HBAs) and hydrogen bond donors (HBDs) on the performance of DESs as hydrotropes for lignin dissolution, while possible dissolution mechanisms in different water/DES compositions were discussed. The capacity of six alcohols (glycerol, ethylene glycol, 1,3-propanediol, 1,4-butanediol, 1,5-pentanediol, and 1,6-hexanediol) and cholinium chloride to enhance the solubility of Kraft lignin in aqueous media was investigated. A correlation between solubility enhancement and the alkyl chain length of the alcohol was observed. This was rationalized upon the competition between hydrotrope–hydrotrope and solute–hydrotrope aggregates with the latter being maximized for 1,4-butanediol. Interestingly, the hydrotropic effect of DESs on lignin solubility is well represented by the independent sum of the dissolving contributions from the corresponding HBAs and HBDs in the diluted region. Conversely, in the concentrated region, the solubility of lignin for a certain hydrotrope concentration was always found to be higher for the pure hydrotropes rather than their combined HBA/HBD counterparts.
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