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Special Issue "Green and Sustainable Solvents"

A special issue of Molecules (ISSN 1420-3049). This special issue belongs to the section "Green Chemistry".

Deadline for manuscript submissions: closed (15 October 2018)

Special Issue Editors

Guest Editor
Prof. Dr. Giancarlo Cravotto

Dipartimento di Scienza e Tecnologia del Farmaco and NIS-Centre forNanostructured Interfaces and Surfaces, University of Turin, Via P.Giuria 9, 10125 Turin, Italy
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Interests: green chemistry; process intensification; green extraction; enabling technologies (ultrasound, microwaves, hydrodynamic cavitation, ball milling, flow chemistry); sustainable chemical processes
Guest Editor
Prof. Dr. Andrioletti Bruno

Université Claude Bernard Lyon 1, Bâtiment Lederer, 69622-Villeurbanne cedex, France
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Interests: green chemistry; synthesis; organometallic chemistry; biomass valorization; catalysis

Special Issue Information

Dear Colleagues,

The ideal solvent should address a number of requirements, including suitable physical and chemical properties, health safety, and a low environmental impact addressing regulatory concerns. Moreover, since 2007, solvents have been regulated at the European level under the Registration, Evaluation, Authorisation and Restriction of Chemicals regulation, known as REACH. In addition to intrinsic green properties and production from renewable resources, solvents sustainability also requires recovery procedures and reuse. Industry and academia have shifted their focus towards developing new bio-based solvents that are environmentally-friendly, as well as several combination on natural deep eutectic solvents. In the quest to achieve sustainability, leading solvent manufacturers have been collaborating with biotechnology firms to manufacture such greener solvents. This Special Issue is aimed at reporting recent advances in the field, and the new routes for green solvents toward industrial applications, highlighting, whenever possible, comparative aspects with classic organic solvents.

Prof. Dr. Giancarlo Cravotto
Prof. Dr. Andrioletti Bruno
Guest Editors

Manuscript Submission Information

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Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 1800 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • Green solvents
  • Bio-based solvents
  • Sustainable solvents
  • Extraction
  • Chemical processing.
  • Green solvent synthesis
  • Green solvent design
  • Uses
  • Extraction
  • Environmental impact

Published Papers (9 papers)

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Research

Open AccessFeature PaperArticle Antiproliferative, Proapoptotic, Antioxidant and Antimicrobial Effects of Sinapis nigra L. and Sinapis alba L. Extracts
Molecules 2018, 23(11), 3004; https://doi.org/10.3390/molecules23113004
Received: 22 October 2018 / Revised: 11 November 2018 / Accepted: 14 November 2018 / Published: 16 November 2018
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Abstract
High Brassicaceae consumption reduces the risk of developing several cancer types, probably due to high levels of glucosinolates. Extracts from Sinapis nigra L. (S. nigra) and Sinapis alba L. (S. alba) have been obtained from leaves and seeds under
[...] Read more.
High Brassicaceae consumption reduces the risk of developing several cancer types, probably due to high levels of glucosinolates. Extracts from Sinapis nigra L. (S. nigra) and Sinapis alba L. (S. alba) have been obtained from leaves and seeds under different conditions using ethanol/water mixtures because their glucosinolates are well accepted by the food industry. The EtOH/H2O 8:2 mixture gives better yields in glucosinolate amounts from ground seeds, mainly, sinalbin in S. alba and sinigrin in S. nigra. The highest antiproliferative activity in both non-tumor and tumor cell lines was induced by S. alba seeds extract. To evaluate whether the effect of Sinapis species (spp) was only due to glucosinolate content or whether it was influenced by the extracts’ complexity, cells were treated with extracts or glucosinolates, in the presence of myrosinase. Pure sinigrin did not modify cell proliferation, while pure sinalbin was less effective than the extract. The addition of myrosinase increased the antiproliferative effects of the S. nigra extract and sinigrin. Antiproliferative activity was correlated to Mitogen-Activated Protein Kinases modulation, which was cell and extract-dependent. Cell-cycle analysis evidenced a proapoptotic effect of S. alba on both tumor cell lines and of S. nigra only on HCT 116. Both extracts showed good antimicrobial activity in disc diffusion tests and on ready-to-eat fresh salad. These results underline the potential effects of Sinapis spp in chemoprevention and food preservation. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Optimization of the Synthesis of Glycerol Derived Monoethers from Glycidol by Means of Heterogeneous Acid Catalysis
Molecules 2018, 23(11), 2887; https://doi.org/10.3390/molecules23112887
Received: 7 October 2018 / Revised: 24 October 2018 / Accepted: 3 November 2018 / Published: 6 November 2018
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Abstract
We present an efficient and green methodology for the synthesis of glycerol monoethers, starting from glycidol and different alcohols, by means of heterogeneous acid catalysis. A scope of Brønsted and Lewis acid catalysts were applied to the benchmark reaction of glycidol and methanol.
[...] Read more.
We present an efficient and green methodology for the synthesis of glycerol monoethers, starting from glycidol and different alcohols, by means of heterogeneous acid catalysis. A scope of Brønsted and Lewis acid catalysts were applied to the benchmark reaction of glycidol and methanol. The selected catalysts were cationic exchangers, such as Nafion NR50, Dowex 50WX2, Amberlyst 15 and K10-Montmorillonite, both in their protonic form and exchanged with Al(III), Zn(II) and Fe(III). Thus, total conversions were reached in short times by using 1 and 5% mol catalyst loading and room temperature, without the need for excess glycidol or the presence of a solvent. Finally, these conditions and the best catalysts were successfully applied to the reaction of glycidol with several alcohols such as butanol or isopropanol. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Lewis Acidity and Basicity of Mixed Chlorometallate Ionic Liquids: Investigations from Surface Analysis and Fukui Function
Molecules 2018, 23(10), 2516; https://doi.org/10.3390/molecules23102516
Received: 29 August 2018 / Revised: 23 September 2018 / Accepted: 29 September 2018 / Published: 30 September 2018
Cited by 1 | PDF Full-text (2200 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Mixed chlorometallate ionic liquids (ILs) have been regarded as potential solvents, catalysts, and reagents for many organic processes. The acidity and basicity of these ILs were correlated with theoretically estimated parameters such as electrostatic surface potential maxima and minima, average local surface ionization
[...] Read more.
Mixed chlorometallate ionic liquids (ILs) have been regarded as potential solvents, catalysts, and reagents for many organic processes. The acidity and basicity of these ILs were correlated with theoretically estimated parameters such as electrostatic surface potential maxima and minima, average local surface ionization energy, and Fukui and dual descriptor functions. The introduction of metal chloride into the anions would influence the acidity/basicity of ILs by withdrawing the electron density from the cationic counterpart. For the [C4mim]-based ILs with the mixed-metal anions, the acidity tends to attenuate while the basicity becomes stronger, as compared to the corresponding chloroaluminate ILs. However, the acidity of [(C2H5)3NH]-based ILs with the mixed-metal anions are greater than that of the net chloroaluminate ILs. The Fukui function values showed that most of the mixed chlorometallate ILs belong to bifunctional distribution. The mixed chlorometallate ILs both have electrophilic and nucleophilic sites, which would be beneficial for their applications. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessFeature PaperArticle Application of Ionic Liquid-Based Ultrasonic-Assisted Extraction of Flavonoids from Bamboo Leaves
Molecules 2018, 23(9), 2309; https://doi.org/10.3390/molecules23092309
Received: 10 August 2018 / Revised: 4 September 2018 / Accepted: 6 September 2018 / Published: 10 September 2018
PDF Full-text (5691 KB) | HTML Full-text | XML Full-text
Abstract
Ionic liquids (ILs), known as environmentally benign “green” solvents, were developed as an optimal solvent for the green extraction and separation field. In this paper, an ionic liquid-based ultrasonic-assisted extraction (IL-UAE) of flavonoids (FVs) from bamboo leaves of Phyllostachys heterocycla was developed for
[...] Read more.
Ionic liquids (ILs), known as environmentally benign “green” solvents, were developed as an optimal solvent for the green extraction and separation field. In this paper, an ionic liquid-based ultrasonic-assisted extraction (IL-UAE) of flavonoids (FVs) from bamboo leaves of Phyllostachys heterocycla was developed for the first time. First, 1-butyl-3-methylimidazolium bromide ([Bmim] Br), with the best extraction efficiency, was selected from fifteen ionic liquids with diverse structure, like carbon chains or anions. Then, the influencing parameters of ionic liquid (IL) concentration, liquid-solid ratio, ultrasonic time, and ultrasonic power, were investigated by single factor tests, and further optimized using response surface methodology (RSM). In the optimization experiment, the best conditions were 1.5 mol/L [BMIM]Br aqueous solution, liquid-solid ratio 41 mL/g, ultrasonic time 90 min, and ultrasonic power 300 W. Furthermore, the microstructures of bamboo leaves and the recovery of FVs and [BMIM]Br were also studied. Therefore, this simple, green and effective IL-UAE method has potentiality for the extraction of FVs from bamboo leaves for the large-scale operations. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Ionic Liquids: Efficient Media for the Lipase-Catalyzed Michael Addition
Molecules 2018, 23(9), 2154; https://doi.org/10.3390/molecules23092154
Received: 5 August 2018 / Revised: 18 August 2018 / Accepted: 25 August 2018 / Published: 27 August 2018
PDF Full-text (1453 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
Recently, ionic liquids (ILs) have been regarded as ideal media for non-aqueous bio-catalysis. In this work, the synthesis of warfarin by the lipase-catalyzed Michael addition in IL media and the parameters that affected the warfarin yield were investigated. Experimental results demonstrated that the
[...] Read more.
Recently, ionic liquids (ILs) have been regarded as ideal media for non-aqueous bio-catalysis. In this work, the synthesis of warfarin by the lipase-catalyzed Michael addition in IL media and the parameters that affected the warfarin yield were investigated. Experimental results demonstrated that the chemical structures of the ILs were a major factor for influencing the warfarin yield. The ILs containing the NTf2 anion were suitable reaction media due to the high chemical stability of this anion. The incorporation of the hydroxyl group on the IL cation significantly improved the lipase activity due to the H2O-mimicking property of this group. The lipase activity decreased by increasing the alkyl chain length on the IL cation due to the non-polar domain formation of the IL cation at the active site entrance of lipase. The ILs and lipase could be reused no less than five times without reduction in the warfarin yield. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Transesterification of Lactic Acid Oligomers with Ethanol, a Way to Anhydrous Ethyl Lactate: A Kinetic Study
Molecules 2018, 23(8), 2044; https://doi.org/10.3390/molecules23082044
Received: 24 July 2018 / Revised: 7 August 2018 / Accepted: 14 August 2018 / Published: 15 August 2018
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Abstract
A new method for the preparation of anhydrous ethyl ester of lactic acid was studied. The selected method is based on catalytic transesterification of lactic acid oligomers, which were prepared for this purpose by autocatalytic oligomerization of lactic acid. In this work, a
[...] Read more.
A new method for the preparation of anhydrous ethyl ester of lactic acid was studied. The selected method is based on catalytic transesterification of lactic acid oligomers, which were prepared for this purpose by autocatalytic oligomerization of lactic acid. In this work, a kinetic model for the case of catalytic alcoholysis of oligoesters was derived assuming a first-order reaction and equimolar content of reactants in the reaction mixture. The model makes it possible to obtain the values of the reaction rate and equilibrium constants and the equilibrium alcohol concentration by regression analysis at one time. The model was verified by measuring the rate of consumption of ethanol over the time at various reaction temperatures with anhydrous FeCl3 as the catalyst. The reaction was studied at overpressure under autogenous conditions in the temperature range of 100–180 °C. For the catalyst concentration of 1 mol %, the activation energy value was 64.35 kJ·mol−1. The dependence of equilibrium composition and rate constant on the temperature was obtained. The derived model is generally applicable to all first-order equilibrium reactions. The presumption is that the forward and reverse reactions are of the same order and have the same stoichiometry and equivalent amounts of reactants at the beginning of the reaction. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Optimisation of Simultaneous Saccharification and Fermentation (SSF) for Biobutanol Production Using Pretreated Oil Palm Empty Fruit Bunch
Molecules 2018, 23(8), 1944; https://doi.org/10.3390/molecules23081944
Received: 13 May 2018 / Revised: 26 June 2018 / Accepted: 26 June 2018 / Published: 3 August 2018
PDF Full-text (1335 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
This study was conducted in order to optimise simultaneous saccharification and fermentation (SSF) for biobutanol production from a pretreated oil palm empty fruit bunch (OPEFB) by Clostridium acetobutylicum ATCC 824. Temperature, initial pH, cellulase loading and substrate concentration were screened using one factor
[...] Read more.
This study was conducted in order to optimise simultaneous saccharification and fermentation (SSF) for biobutanol production from a pretreated oil palm empty fruit bunch (OPEFB) by Clostridium acetobutylicum ATCC 824. Temperature, initial pH, cellulase loading and substrate concentration were screened using one factor at a time (OFAT) and further statistically optimised by central composite design (CCD) using the response surface methodology (RSM) approach. Approximately 2.47 g/L of biobutanol concentration and 0.10 g/g of biobutanol yield were obtained after being screened through OFAT with 29.55% increment (1.42 fold). The optimised conditions for SSF after CCD were: temperature of 35 °C, initial pH of 5.5, cellulase loading of 15 FPU/g-substrate and substrate concentration of 5% (w/v). This optimisation study resulted in 55.95% increment (2.14 fold) of biobutanol concentration equivalent to 3.97 g/L and biobutanol yield of 0.16 g/g. The model and optimisation design obtained from this study are important for further improvement of biobutanol production, especially in consolidated bioprocessing technology. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Environmentally Friendly Approach to Knoevenagel Condensation of Rhodanine in Choline Chloride: Urea Deep Eutectic Solvent and QSAR Studies on Their Antioxidant Activity
Molecules 2018, 23(8), 1897; https://doi.org/10.3390/molecules23081897
Received: 27 June 2018 / Revised: 16 July 2018 / Accepted: 27 July 2018 / Published: 29 July 2018
PDF Full-text (3798 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
A series of rhodanine derivatives was synthesized in the Knoevenagel condensation of rhodanine and different aldehydes using choline chloride:urea (1:2) deep eutectic solvent. This environmentally friendly and catalyst free approach was very effective in the condensation of rhodanine with commercially available aldehydes, as
[...] Read more.
A series of rhodanine derivatives was synthesized in the Knoevenagel condensation of rhodanine and different aldehydes using choline chloride:urea (1:2) deep eutectic solvent. This environmentally friendly and catalyst free approach was very effective in the condensation of rhodanine with commercially available aldehydes, as well as the ones synthesized in our laboratory. All rhodanine derivatives were subjected to 1,1-diphenyl-2-picrylhydrazyl radical (DPPH) scavenging activity investigation and quantitative structure-activity relationship (QSAR) studies were performed to elucidate their structure-activity relationship. The best multiple linear QSAR model demonstrate a stability in the internal validation and Y-randomization (R2 = 0.81; F = 24.225; Q2loo = 0.72; R2Yscr = 0.148). Sphericity of the molecule, ratio of symmetric atoms enhanced atomic mass along the principle axes in regard to total number of atoms in molecule, and 3D distribution of the atoms higher electronegativity (O, N, and S) in molecules are important characteristic for antioxidant ability of rhodanine derivatives. Molecular docking studies were carried out in order to explain in silico antioxidant studies, a specific protein tyrosine kinase (2HCK). The binding interactions of the most active compound have shown strong hydrogen bonding and van der Waals interactions with the target protein. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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Open AccessArticle Sodium Copper Chlorophyllin Catalyzed Chemoselective Oxidation of Benzylic Alcohols and Diarylmethanes in Water
Molecules 2018, 23(8), 1883; https://doi.org/10.3390/molecules23081883
Received: 26 June 2018 / Revised: 16 July 2018 / Accepted: 26 July 2018 / Published: 27 July 2018
PDF Full-text (3085 KB) | HTML Full-text | XML Full-text | Supplementary Files
Abstract
We report the highly efficient and chemoselective oxidation of benzylic alcohols catalyzed by sodium copper chlorophyllin in water, producing corresponding arylcarbonyl compounds. Importantly, the catalytic system exhibits a wide substrate scope and high functional group tolerance. Moreover, secondary alcohols and even diarylmethanes were
[...] Read more.
We report the highly efficient and chemoselective oxidation of benzylic alcohols catalyzed by sodium copper chlorophyllin in water, producing corresponding arylcarbonyl compounds. Importantly, the catalytic system exhibits a wide substrate scope and high functional group tolerance. Moreover, secondary alcohols and even diarylmethanes were smoothly oxidized to the desired aryl ketones with excellent yields. Full article
(This article belongs to the Special Issue Green and Sustainable Solvents)
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