This study presents a sustainable valorization route for Pinus radiata sawdust, transforming forestry waste into high-purity, lignin-derived biochar through green-solvent organosolv extraction followed by controlled thermochemical conversion. The influence of solvent selection on lignin structure, morphology, and thermal behavior was systematically investigated using γ-valerolactone (γ-VL), glycolic acid (GA), and lactic acid (LA). Among the tested systems, pure γ-VL achieved high lignin recovery (∼85%) and produced precursors with superior thermal stability (Tonset = 375.6 °C). Pyrolysis at 850 °C resulted in biochars with carbon enrichment exceeding 85%, with γ-VL-derived samples reaching 88.96% carbon and minimal oxygen residuals. FE-SEM analysis suggested partial preservation of the precursor morphology after pyrolysis, where γ-VL templated uniform spherical micro-particles, contrasting with the laminar and fibrillar structures of GA and industrial Kraft benchmarks, respectively. Notably, the γ-VL biochar exhibited a superior specific surface area of 167.4 m2/g and a high mesoporosity of 86.6% (pore diameter ∼3 nm), significantly outperforming the industrial Kraft biochar (48.0% mesoporosity). Raman spectroscopy confirmed a predominantly amorphous carbon framework, with fitted ID/IG ratios ranging from 1.01 to 1.10. These findings demonstrate that green solvents act as tools for tailoring biochar architecture and provide valuable insights for the design of lignin-derived porous carbon materials for future evaluation in adsorption and energy-related technologies.

Green chemistry promotes the design and application of chemical products and processes that reduce or preferably eliminate the use and generation of hazardous substances. The objective of this research was to evaluate the environmental performance of two methods of producing nanocellulose at the laboratory scale: (i) a conventional sulphuric acid hydrolysis that has been upscaled for industrial use (TRL 8-9); and (ii) the novel approach using the ternary eutectic mixture ChCl: pTSA: PA molar ratio (1:1:1.35) that is currently at TRL 2. The purpose of developing the new approach was to find a better alternative to the conventional process from an environmental perspective. To validate this, life cycle assessment was used to compare conventional vs novel methods with the functional unit of 1 g nanocellulose produced. The system boundary was from cradle to laboratory gate. The results were interpreted to select the best method for laboratory use and to identify design issues to address during upscaling of the novel method. For both methods, conventional and novel, the impact categories selected were climate change (kgCO2 eq), Acidification (kg SO2 eq), Ecotox Air (CTUe) and Eutrophication (kg N eq). To produce 1 g of nanocellulose with sulphuric acid caused a climate impact of between 68 kg CO2 eq (90 % yield) to 105 kg CO2 eq (57 % yield). Produced using DES the climate impact ranged from 85 kg CO2 eq.(90 % yield) to 132 kg CO2 (57 % yield). The results indicated that the novel method created greater impacts over the whole life cycle. Unless significant changes are made during upscaling, the novel method will not make a positive contribution to sustainable, circular bioeconomy. The method does have potential to be improved to reduce impact, including using decarbonised energy, a renewable, bio-based feedstock for the cellulose and choline chloride to improve the overall efficiency of using deep eutectic solvent (DES) at pilot scale. The low TRL life cycle assessment offered insights not possible if only the laboratory stage of the analysis had been considered.

The preferential solvation of two perichromic dyes, 4-amino-N-methylphthalimide (4-AMP) and Nile Red (NR) in binary mixtures of an ionic liquid ([bmim][X], where X = BF4, PF6, Tf2N and DCA) with a protic or non-protic solvent, was investigated, in search of examples of a synergetic or "hyperpolar" behavior. Synergism was generally observed in those mixtures where the two pure components had similar polarity values, according to the employed probe. A parallel was drawn between the observed synergism in these IL mixtures and the phenomenon of hydrotropism, also observed with organic solutes in aqueous IL mixtures. More generally, in binary mixtures with organic solvents, ionic liquids can act as solvatotropes, promoting the dye solvation by formation of solute-specific aggregates with all species present in the mixture. By stabilizing the dipolar excited state of 4-AMP or NR through hydrogen-bonds and electrostatic interactions in these aggregates, a "hyperpolar" milieu is generated, which surpasses the polarities of the two pure components. Solvatotropism seems to offer a more realistic picture than the solvent-exchange model, originally developed for simpler systems, to the phenomenon of preferential solvation in binary mixtures with ionic liquids.

Deep eutectic solvents (DES) formed using choline chloride (ChCl), p-toluenesulfonic acid (pTSA) of stoichiometry ChCl: pTSA (1:1) and (1:2), and its ternary eutectic mixtures with phosphoric acid (PA) 85% as an additive (ChCl: pTSA: PA) were evaluated for cellulose nanocrystal (CNC) isolation. Initially, the hydrolytic efficiency to produce CNC of each DES was compared before and after adding phosphoric acid by Hammett acidity parameters and the Gutmann acceptor number. Moreover, different DES molar ratios and reaction time were studied at 80°C for CNC optimization. The nanomaterial characteristics were analyzed by field emission scanning electron microscopy (FESEM), X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FTIR), and thermogravimetric analysis (TGA). The ternary eutectic mixture ChCl: pTSA: PA molar ratio (1:1:1.35) was chosen as a suitable recyclable ternary system at the laboratory scale. A CNC yield of about 80% was obtained from the hydrolysis of commercial cellulose in five cycles of recovery, but it dropped to 35% in pre-pilot scaling. However, no variation in the average size of the resulting CNC was observed (132 ± 50 nm x 23 ± 4 nm), which presented high thermal stability (Tmax 362°C) and high crystallinity of about 80% after 3 h of reaction time.

In this article, we present a complementary experimental and theoretical study for designing a task specific medium for the ultrasound extraction of polyphenols of Luma apiculata. Our results reveal that choline chloride-based DESs are suitable candidates as extraction media. To capture the role of the solvent in the extraction process, we employed molecular dynamics simulation of a model solute surrounded by different DESs. Results showed that an adequate DES should have an organic acid, an amine or quaternary ammonium salt, a content of water for the formation of the eutectic mixture, and an acidic anion. The importance and role of each component could be rationalized by their synergetic solvation of the polyphenols.(c) 2022 Elsevier B.V. All rights reserved.

Solutions of a pure organic solvent acidified with 1% sulfuric acid, and some of their aqueous mixtures were used for lignin extraction in the Pinus radiata sawdust delignification. Organic acid solvents including acetic, lactic and citric acids as well as non-acidic compounds such as γ-valerolactone, 2-methyltetrahydrofuran, glycerol and ethylene glycol were studied. Crude lignin extractions yields (%) ranging between ca. 5–50% were obtained, from which ethylene glycol (33%), γ-valerolactone (48%) and propylene carbonate (52%) showed the greatest effectiveness. The effect of added water on the lignin extraction was investigated in mixtures of an organic solvent with a variable water content (75%w/w, 50% w/w, 25%w/w and 10% w/w) where it was observed that the yield of extraction decreased with the increased water content. Moreover, the purity of extracted lignins were analyzed by spectroscopic methods (UV and IR). Kamlet-Taft solvent polarity parameters, were determined with the solvatochromic probes 4-nitroaniline, N,N-diethyl-4-nitroaniline, Nile Red and 6-propionyl-2-N,N-dimethylaminonaphthalene (PRODAN), and then correlated to lignin extraction yields to explain the influence of the solute-solvent interactions on biomass delignification. A reasonable correlation was found between the medium polarizability-dipolarity π* and the effectiveness of the solvent mixture on the extraction of lignin wood.

The non-ideality approach for the comparison of different properties of related binary mixtures of deep eutectic solvents (DESs) is illustrated with seventy examples from the literature. A preferential-solvation index (PSI) is used to compare polarities and the preferential solvation of solvatochromic probes in these systems. A non-ideality index (NII) and/or area (NIA) allow the comparison of thermodynamic properties of related mixtures. The approach, which is of easy application from experimental plots, can in principle be used for the comparison of any property of related binary mixtures of DESs. It is not based on theoretical assumptions and complements existing models, by comparing scattered data from different sources and revealing unexpected trends or patterns with a predictive power. It thus represents a simple alternative to the problem of interpreting and predicting the behavior of such complex, multi-component mixtures, which defy the application of theoretical models to their rationalization. (c) 2022 Elsevier B.V. All rights reserved.

Human leukotriene A4 hydrolase enzyme (LTA4H) catalyses the biotransformation of the inactive precursor leukotriene A4 (LTA4) to the bioactive Leukotriene B4 (LTB4), which causes many inflammatory responses in the human body. Therefore, the selective inhibition of this enzyme becomes a useful strategy for the treatment of several illnesses such as asthma, allergic rhinitis, cardiovascular diseases, and cancer. Herein we report a 3D-QSAR/ /CoMFA and CoMSIA study on a series of 47 benzimidazoles, benzoxazoles, benzothiazoles and thiazolopyridines reported as potent LTA4H inhibitors. Good statistical parameters were obtained for the best model (q2 = 0.568, r2 ncv = 0.891 and r2 test = 0.851). A new series of 10 compounds capable of inhibiting leukotriene A4 hydrolase with high potency was presented. All designed inhibitors showed low IC50 in nano- and sub-nanomolar ranges, when they were evaluated in 3D-QSAR models. Subsequently, the designed molecules, as well as the least and most active compounds were subjected to docking and molecular dynamics studies into LTA4H. In conclusion, we summarised a thorough structure?activity relationship (SAR) of LTA4H inhibitors of heterocyclic structure. These models can be used for the rational proposal of new inhibitors.

Although aqueous biphasic systems have been largely investigated in the separation and/or purification of biocompounds, their potential as reaction media to design integrated reaction-separation processes has been less explored. In this work aqueous biphasic systems (ABSs) composed of polypropylene glycol of molecular weight 400 g mol-1 (PPG 400) and different polyethylene glycols (PEGs) were characterized, and investigated for integrated reaction-separation processes, i.e. in the nucleophilic degradation of diazinon and further separation of reaction products by taking advantage of the lower-critical solution temperature (LCST) behaviour of these ABSs. The nucleophilic degradation of diazinon was carried out in the monophasic regime at 298 K, after which an increase in temperature (up to 313 K) allowed the product separation by two-phase formation (thermoreversible systems). The reaction kinetics and reaction pathways have been determined. The reaction kinetic increases as the PEG molecular weight decreases, with the half-life values obtained being competitive to those previously reported using volatile organic solvents as solvent media and significantly higher than under alkaline hydrolysis. One reaction pathway occurs in ABSs comprising PEGs of higher molecular weights, whereas in the ABS composed of PEG 600 two reaction pathways have been identified, meaning that the reaction pathways can be tailored by changing the PEG nature. ABSs formed by PEGs of lower molecular weights were identified as the most promising option to separate the pesticide degradation products by simply applying changes in temperature.

EDITORIAL article Front. Chem., 03 December 2021 | https://doi.org/10.3389/fchem.2021.803431

Propylene carbonate is becoming a suitable green alternative to volatile organic solvents in the study of chemical reactions. In this study, an efficient method for nucleophilic degradation of five organophosphorus pesticides, fenitrothion, malathion, diazinon, parathion, and paraoxon, using propylene carbonate as a solvent is proposed. The effect of changing the nature of the nucleophile and the influence of microwave (MW) heating were investigated. A screening of temperatures (50 °C-120 °C) was performed under microwave heating. The pesticide degradation was followed by 31P NMR, and the extent of conversion (%) was calculated by the integration of phosphorus signals. Keeping in mind that recently it has been reported that some ionic liquids play a nucleophilic role, in this work we report for the first time the degradation of organophosphorus pesticides by using an amino acid-based ionic liquid such as Bmim[Ala] as a nucleophile and a bio-based solvent (propylene carbonate) as a reaction medium in combination with microwave heating.

A series of ionic liquids (ILs) composed by choline (Ch) as a cation and different amino acids (AA) as anions and their respective aqueous mixtures were prepared using different [Ch][AA] contents in a range of 0.4-46 mol % IL. These solvents were used for the first time to achieve an eco-friendlier Paraoxon degradation. The results show that [Ch][AA]/water mixtures are an effective reaction medium to degrade Paraoxon, even when the IL content in the mixture is low (0.4 mol % IL) and without the need of an extra nucleophile. Both the kinetics and the degradation pathways of pesticides depend on the nature of the AA on [Ch][AA] and the amount of an IL present in the mixture. We have demonstrated that in those mixtures with a low amount of [Ch][AA], the hydrolysis reaction is the main pathway for Paraoxon degradation, showing a catalytic effect of the IL. However, as the percentage of [Ch][AA] increases in the mixture, the nucleophilic attack of [Ch][AA] is evident. Finally, the aim of this study was to provide evidence of a promising and biocompatible methodology to degrade a toxic compound (Paraoxon) using a minimal quantity of an IL designed totally from natural resources.

An efficient strategy for the degradation of organophosphate pesticide Diazinon was investigated. In this work, ionic liquids, bio-based solvents, and two conventional organic solvents were used as reaction media. Kinetics studies by means of half-life (t1/2,h) were followed by 31P NMR and the products analyzed by GC-MS, HPLC-MS and NMR techniques. These results have shown that t1/2 values in ionic liquids were the lowest and also they were able to activate two electrophilic centers in Diazinon, whilst degradation in bio-based solvents occurred slowly by only an aromatic pathway. In addition, a study to estimate the influence of green activation techniques was carried out by using Ultrasound irradiation and Microwave heating in combination with greener solvents and two conventional organic solvents. Under Microwave heating, faster degradation than under ultrasound irradiation was found. Finally, considering both families of solvent used here and their behavior under green activation techniques, we propose that the more efficient way for degradation of Diazinon with piperidine is by microwave heating using ionic liquids as solvents.

The synthesis of a series of ionic liquids using 1-butyl 3-methylimidazolium (Bmim+) as a cation and different amino acids (AA) as anions (Bmim[AA]) is described. These ILs were used for the first time as reaction media to achieve more eco-friendly Paraoxon degradation. The results show that the degradation of Paraoxon in these Bmim[AA]s is accomplished with great efficiency and without an extra nucleophilic agent. Therefore, we propose that all the Bmim[AA]s used in this study have a dual role in the outcome of this reaction; as a nucleophile and a solvent to carry out degradation of the organophosphorous pesticide, Paraoxon. Both kinetics and product distribution results found in this study for Paraoxon degradation turned out to be promising, because this process is achieved in a reaction medium with a better environmental profile.

A brief review of Chilean policies on sustainability along with the academic efforts related to green chemistry, in order with this new scenario are discussed. Topics considered are extraction processes, new solvents, CO2 transformation and emerging photovoltaics materials.

Water contamination is one of the main problems of modem society, and scientific research is continuously involved in identifying solutions able to preserve this valuable source. In this context, we characterized novel ionogels formed by organic salts with different anions. In particular, they show self-strengthening behavior, a quite unusual property for supramolecular gels, and they also exhibit a good load-bearing capacity. These ionogels are able to remove cationic dyes from wastewater. Thanks to their properties, they can be used in different apparatuses like dialysis membranes and as loading in adsorption columns. In the latter case over 95% removal is achieved in less than 10 min. Interestingly, soft materials can be reused for at least 20 cycles, partially regenerated, and reused for further 15 cycles. Comparison with data previously reported in the literature shows that this is a prerogative of this system and this represents not only an improvement but also a warranty of low raw material production after wastewater treatment.

Considering the main characteristics of ionic liquids versus bio-based solvents, which is the most appropriate solvent for degradation of some organophosphorate pesticides in order to obtain a more eco-friendly process? The solvent effect was studied by mean of half-lives (t(1/2), h) through a kinetic study, which was followed by P-31 NMR and UV/vis. The results showed that the use of bio-based solvents as media for degradation of Fenitrothion (1) and Paraoxon (2) not only leads to a more efficient degradation but also assures a more sustainable process.

In this work, we report a kinetic study of the reactions of the title compound with secondary alicyclic amines at different temperatures in acetonitrile and several ionic liquids (ILs). From this study, we have described that the reactions in MeCN and in the studied ILs occur by a concerted mechanism and that the activation parameters are sensitive to the structural properties of the ILs. The pKa values of all amines used in both MeCN and ILs were determined.

Correction for ‘Reaction mechanisms in ionic liquids: the kinetics and mechanism of the reaction of O,O-diethyl (2,4-dinitrophenyl) phosphate triester with secondary alicyclic amines’ by Paulina Pavez et al., Org. Biomol. Chem., 2016, DOI: 10.1039/c5ob02128f.