Search Results (102)

Interfacial polymerization (IP) has been widely utilized to synthesize composite membranes. However, precise control of this reaction remains a challenge due to the complexity of the IP process. Herein, an optical three-dimensional microscope was used to directly observe the IP process. To construct copolyesteramide containing phthalazine moiety films, rigid monomer 4-(4′-hydroxyphenyl)-2,3-phthalazin-1-one (DHPZ) and flexible monomer piperazine (PIP) were used as aqueous phase monomers, and trimesoyl chloride (TMC) served as the organic phase monomer. Multilayer cellular structures were observed for the copolyesteramide films during the IP process. The effects of multiple factors including the ratio between flexible and rigid monomers, co-solvents, and the addition of phase transfer catalysts on the film growth and the morphologies were investigated. This research aims to deepen our understanding of the IP process, especially for the principles which govern polymer film growth and morphology, to promote new methodologies for regulating interfacial polymerization in composite membrane preparation. Full article

Icariside I, a bioactive flavonoid derivative derived from Herba epimedii, demonstrates better pharmacological properties compared to its precursor icariin. Enzymatic conversion of icariin to icariside I using α-L-rhamnosidase represents an efficient biotechnological approach. In this study, we characterized a GH78 family α-L-rhamnosidase from Dictyoglomus thermophilum (DthRha) with promising biocatalytic properties. The recombinant DthRha displayed optimal activity at 55 °C and pH 6.0, with remarkable thermostability (retaining > 80% activity after 1 h at 45–65 °C) and pH stability (pH 5.0–7.0). The kinetic parameters K_m, k_cat and k_cat/K_m values for pNPR of 0.44 mM, 7.99 s⁻¹ and 18.16 s⁻¹ mM⁻¹, respectively. Notably, DthRha exhibited good organic solvent tolerance, retaining > 50% activity after 4 h in 10% DMSO. Applied in a DMSO cosolvent system, DthRha achieved 92.3% conversion of icariin to icariside I within 4 h under optimized conditions. Interestingly, elevating the substrate concentration to 10 mM resulted in a consistently high icariin conversion of 95.8%. The enzymatic hydrolysis method can be applied to the industrial production of Icariside I. Furthermore, DthRha not only cleaves the α-1,2 glycosidic bond between glucoside and rhamnoside in compounds like naringin, but also exhibits tolerance to organic solvents, making it suitable for the hydrolysis of other poorly soluble flavonoids. Full article

Albumin-based nanoparticles are promising drug delivery systems due to their biocompatibility, biodegradability, and ability to improve targeted drug release. Among various preparation methods, radiation-induced cross-linking in the presence of ethanol has been proposed in the literature as an effective method for producing protein nanoparticles with preserved bioactivity and controlled size. However, the mechanisms by which ethanol radicals contribute to protein aggregation remain insufficiently understood. In this study, we investigate the role of ethanol in the aggregation of albumins to determine whether its presence is necessary or beneficial for nanoparticle formation. Using pulse radiolysis, spectroscopy methods, resonance light scattering (RLS), and near-infrared (NIR) spectroscopy, we examined aqueous ethanol solutions of albumins before and after irradiation. Our results show that ethanol concentrations above 40% (v/v) significantly promote both radiation-induced and spontaneous protein aggregation. Mechanistic analysis indicates that ethanol radicals react with albumin similarly to hydrated electrons, mainly targeting disulfide bridges. This reaction leads to the formation of sulfur-centered radicals and the formation of intermolecular disulfide bonds that stabilize protein nanostructures by excluding the formation of dityrosine bridges, as described in the literature. In contrast, ethanol concentration below 40% does not favor the radiation-induced aggregation compared to the solution containing t-BuOH. These results provide novel insights into the role of organic cosolvents in protein aggregation and contribute to a broader understanding of the mechanisms of formation of albumin-based nanoparticles using ionizing radiation. Full article

This study evaluated the acute and developmental toxicity of selected hydrotropes, co-solvents, and surfactants commonly used in pharmaceutical and cosmetic formulations, using Artemia salina as a model organism. Two bioassays were employed: a lethality test and a hatching inhibition test. Compounds such as sodium lauryl sulfate (LC₅₀ < 0.05%), sodium xylenesulfonate (LC₅₀ = 0.79%), sodium p-toluensulfonate (LC₅₀ = 0.21%), N,N-dimethylbenzamide (LC₅₀ < 0.05%), and N,N-diethylnicotinamide (LC₅₀ = 0.05%) exhibited high toxicity at 48 h, inducing significant mortality and strong inhibition of hatching. Glycerin, propylene glycol, and dimethyl sulfoxide showed low toxicity across all concentrations. Lethal concentration values confirmed the high toxicity of sodium xylenesulfonate and N,N-dimethylbenzamide, with moderate effects observed for other compounds. The hatching inhibition test proved more sensitive than the lethality test, enabling the detection of embryotoxicity and developmental delays. Although more laborious, it provided detailed information into how the tested substances influenced developmental stage progression. Hierarchical clustering analysis grouped the substances based on toxicity patterns and clearly discriminated highly toxic surfactants from low-toxicity solvents. The results demonstrated that combining both bioassays offers a more comprehensive evaluation of toxicity, with the hatching test being particularly useful for identifying early developmental effects not evident in lethality testing alone. Full article

Ionic liquids (ILs) have attracted increasing attention due to their unique physicochemical properties. Among them, 1-Methyl-1-propylpyrrolidinium bis(trifluoromethanesulfonyl)imide, emerges as an ideal candidate for fundamental studies in electrochemical applications. This work aims to deepen the understanding of its conductivity performance, and potential interaction with added metal salts, providing insight into its applicability in advanced energy storage systems. Firstly, binary mixtures with ethylene carbonate have been prepared to improve the transport properties and select the optimal concentration of both components. Subsequently, lithium salt was added to design the adequate electrolyte. The thermal and electrochemical characterisation of these mixtures was performed by differential scanning calorimetry (DSC) thermogravimetric analysis (TGA) and Broad Band Dielectric Spectroscopy (BBDS). The results reveal a wide liquid range for the ternary systems studied, extending below −80 °C and above 120 °C. Additionally, they exhibit notably high conductivity values at room temperature (ranging from 0.2 S·m⁻¹ for the most concentrated to 0.70 S·m⁻¹ for the lowest concentrated), which highlights their suitability for advanced electrochemical applications, including but not limited to batteries. This extended liquid phase mitigates, or potentially eliminates, some of the most common issues associated with current electrolytes, such as undesired crystallisation at low temperatures. In this paper, a new promising electrolyte, consisting of a ternary mixture obtained by adding lithium salt to the eutectic composition of [C₃C₁Pyrr][TFSI] and ethyl carbonate is proposed. Full article

Bisphenol A is a widely recognized endocrine disruptor that persists in ecosystems, harms aquatic organisms, and contributes to ecological degradation, raising global environmental concerns. Numerous studies have explored β-cyclodextrin–based adsorbents for Bisphenol A removal; however, their regeneration remains a major challenge, often relying on energy-intensive processes and excessive use of organic solvents. In this study, Bisphenol A was selected as a model pollutant, and its adsorption onto β-cyclodextrin nanosponges was investigated. After adsorption, Bisphenol A was efficiently recovered from the saturated β-cyclodextrin nanosponges using an innovative and sustainable supercritical CO₂-based green process, which simultaneously regenerated the adsorbent. The adsorption process achieved an efficiency of 95.51 ± 0.82% under optimized conditions (C₀ = 150 mg/L, m_β-CDNS = 0.15 g, T = 25 °C, and N = 200 rpm), with a maximum adsorption capacity of 47.75 ± 0.28 mg/g. The regeneration process achieved over 99% efficiency at 60 °C and 300 bar, with 10% (v/v) ethanol as a co-solvent, nearly fully restoring the adsorbent’s performance. Unlike conventional regeneration techniques, this green approach eliminates the need for environmentally harmful organic solvents while preserving the adsorbent’s structural integrity, making it a highly efficient and sustainable alternative. This study is the first to demonstrate the effective application of supercritical CO₂-based regeneration for β-cyclodextrin nanosponges in Bisphenol A removal, providing a scalable and environmentally sustainable solution for wastewater treatment. Furthermore, characterization analyses confirmed that the adsorbent retained its chemical and morphological stability after adsorption and regeneration. Full article

Supercritical CO₂ (scCO₂) is a versatile solvent for polymer processing; however, many partially fluorinated polymers exhibit limited solubility in neat scCO₂. Organic cosolvents such as toluene can enhance polymer–solvent interactions, thereby improving solubility. The cloud point behavior of poly(2,2,2-trifluoroethyl methacrylate) (poly(TFEMA)) at 3 wt% concentration in scCO₂–toluene binary mixtures was investigated over a temperature range of 31.5–50 °C and toluene contents of 0–20 wt%. Solvent mixture densities were estimated using the Altuin–Gadetskii–Haar–Gallagher–Kell (AG–HGK) equation of state for CO₂ and the Tait equation for toluene. For all compositions, the cloud point pressure was observed to increase linearly with temperature. The cloud point pressure decreased monotonically with increasing toluene concentration and at the highest concentration of 20 wt% was reduced by approximately 40% in comparison to neat scCO₂. The addition of toluene lowered the solvent density, but the increase in solvent–solute molecular interactions resulted in the observed decrease in cloud point pressure. Toluene is shown to be an effective cosolvent for dissolving poly(TFEMA) in scCO₂, offering a promising approach to lowering operating pressures in fluoropolymer processing. Our results provide valuable phase behavior data for designing scCO₂-based extraction, impregnation, and particle formation processes involving poly(TFEMA). Full article

Gelled fuels are rheologically complex, non-Newtonian fluids. They combine the benefits of both liquid and solid states, reducing risks of leakage, spilling, and sloshing during storage while maintaining the ability to be sprayed inside a combustion chamber. Additionally, suspending energetic particles, such as metal powders of aluminum and boron, can significantly enhance their energy density compared to conventional liquid fuels. In this study, several kerosene-based and ethanol-based formulations were experimentally investigated, using both organic and inorganic gelling agents. The compositions were optimized in terms of the gellant amount and manufacturing process. Some of the most promising gellants for kerosene include fatty acids, such as Thixcin^® R or THIXATROL^® ST, and metallic soaps, such as aluminum stearate and zinc stearate. The effects of various co-solvents were assessed, including ketones (methyl isoamyl ketone, methyl ethyl ketone, and acetone) and alcohols (ethanol and octadecanol). Sugar polymers like hydroxypropyl cellulose were tested as gelling agents for ethanol. A preliminary rheological analysis was conducted to characterize their behavior at rest and under shear stress. Finally, a novel approach was introduced to study the stability of the gels under vibration, which was derived from a realistic mission profile of a ramjet. Finally, the ideal gravimetric specific impulse was evaluated through ideal thermochemical computations. The results showed that promising formulations can be found in both kerosene-based and ethanol-based gels. Such compositions are of interest in practical airbreathing applications as they have demonstrated excellent stability under vibration, ideal combustion properties, and pronounced shear-thinning behavior. Full article

The use of supercritical carbon dioxide (ScCO₂) as a replacement for volatile organic solvents in coatings has the potential to reduce air pollution. This paper presents the findings of a molecular dynamics simulation study investigating the dissolution behavior of polyvinylidene fluoride (PVDF) in ScCO₂ assisted by five co-solvents. On the basis of solubility parameters, interaction binding energy, and radial distribution functions, the impacts of temperature, pressure, and co-solvents on the compatibility of ScCO₂ and PVDF were investigated at the microscopic level. The simulation results demonstrated that low-temperature and high-pressure conditions facilitate the dissolution of PVDF in ScCO₂, where the optimal conditions are 308.15 K and 16 MPa. The enhancement of the solubility performance of ScCO₂ slowed down with increasing pressure, but was more sensitive to changes in temperature. The weak attraction between PVDF and ScCO₂ was synergized by van der Waals and electrostatic forces, making it challenging to achieve complete and homogeneous mixing. The use of co-solvents with strong polarity can enhance the solvent system’s solubility. Ethanol and 2-butoxy-1-ethanol have obvious solubilizing abilities due to the hydrogen bond donors, which can generate hydrogen bonding interactions with ScCO₂, increase the polarity of the solvent system, and promote the compatibility of ScCO₂ with PVDF. Full article

Background: Ketamine HCl, an FDA-approved therapeutic, is administered through various routes, including intranasal delivery. Administering an adequate therapeutic dose of intranasal ketamine HCl is challenging due to the limited volume that can be delivered intranasally given the current commercially available concentrations. Objectives: This study investigates solubilizing strategies to enhance the aqueous solubility of ketamine HCl for intranasal administration. Methods: We assessed the solubility profile of ketamine HCl by evaluating factors such as pH, co-solvents, and surfactants. Additionally, we developed and validated a UV-Vis spectroscopy method for ketamine HCl analysis. Results: Our solubility screening in various organic co-solvents revealed the following order of effectiveness in enhancing solubility: methanol > water > propylene glycol > ethanol > dimethyl sulfoxide (DMSO) > N-methyl-2-pyrrolidone (NMP). Despite methanol’s superior solubility, its potential toxicity, coupled with the relatively lower effectiveness of other solvents compared to water, suggests that a co-solvency approach is not advantageous for ketamine HCl. We found that ketamine HCl solubility increased with medium acidity, with pH 3.5 being the optimal for further formulation studies. The impact of pharmaceutical surfactants on ketamine HCl solubility at an acidic pH was also evaluated. Surfactants tested included SDS, PEG 400, PVP, Tween 20, poloxamer 188, and lecithin. Notably, PEG 400 and PVP reduced solubility due to a salting-out effect, whereas Tween 80, lecithin, and poloxamer 188 slightly improved solubility through micelle formation. Among the surfactants tested, 1% SDS emerged as the most effective in enhancing ketamine HCl solubility. Conclusions: These outcomes highlight the potential of these solubilization strategies to address the solubility limitations of ketamine HCl, enabling the preparation of highly concentrated ketamine HCl formulations for intranasal delivery. Full article

Carotenoids are high added-value products primarily known for their intense coloration and high antioxidant activity. They can be extracted from a variety of natural sources, such as plants, animals, microalgae, yeasts, and bacteria. Gordonia alkanivorans strain 1B is a bacterium recognized as a hyper-pigment producer. However, due to its adaptations to its natural habitat, hydrocarbon-contaminated soils, strain 1B is resistant to different organic solvents, making carotenoid extraction through conventional methods more laborious and inefficient. Ionic liquids (ILs) have been abundantly shown to increase carotenoid extraction in plants, microalgae, and yeast; however, there is limited information regarding bacterial carotenoid extraction, especially for the Gordonia genus. Therefore, the main goal of this study was to evaluate the potential of ILs to mediate bacterial carotenoid extraction and develop a method to achieve higher yields with fewer pre-processing steps. In this context, an initial screening was performed with biomass of strain 1B and nineteen different ILs in various conditions, revealing that tributyl(ethyl)phosphonium diethyl phosphate (IL#18), combined with ethyl acetate (EAc) as a co-solvent, presented the highest level of carotenoid extraction. Afterward, to better understand the process and optimize the extraction results, two experimental designs were performed, varying the amounts of IL#18 and EAc used. These allowed the establishment of 50 µL of IL#18 with 1125 µL of EAc, for 400 µL of biomass (cell suspension with about 36 g/L), as the ideal conditions to achieve maximal carotenoid extraction. Compared to the conventional extraction method using DMSO, this novel procedure eliminates the need for biomass drying, reduces extraction temperatures from 50 °C to 22 ± 2 °C, and increases carotenoid extraction by 264%, allowing a near-complete recovery of carotenoids contained in the biomass. These results highlight the great potential of ILs for bacterial carotenoid extraction, increasing the process efficiency, while potentially reducing energy consumption, related costs, and emissions. Full article

Liquefaction conversion technology has become one of the hottest biomass conversion methods due to its flexible material selection and extensive product applications. Exploring biomass liquefaction conversion focuses on catalysts, biomass/water ratio, and reaction temperature. However, it is found that solvents are crucial in the biomass liquefaction process and significantly impact the type of liquefied products and bio-oil yield. Given the current rapid development trend, timely sorting and summary of the solvent effect in the biomass liquefaction process can promote the subsequent development and industrialization of more efficient and cleaner biomass liquefaction technology. Therefore, this review first introduces the characteristics of water as the liquefaction solvent, then summarizes the effects of organic solvents on liquefaction, and finally elaborates on the synergistic effect of co-solvents, which provides a more systematic overview of solvent effects in the liquefaction process. Meanwhile, prospects are put forward for the future development of biomass liquefaction conversion. Full article

The objective of this research was to investigate and compare the results obtained in the intensification and integration of (sc-CO₂) under different pressure conditions (25 and 30 MPa) at 60 °C. When intensifying the process, ethanol (10%) was used as a co-solvent (sc-CO₂ + EtOH). In the process integration, black soldier fly larvae flour, defatted via supercritical extraction (SFE), was the raw material for pressurized liquid extraction (PLE) using ethanol as solvent. The extract yields, fatty acid profile, free fatty acids, triacylglycerols (TAGs), oxidative stability, and nutritional quality of the oil obtained using sc-CO₂ + EtOH were evaluated. The composition of bioactive compounds (carotenoids, acidity, antioxidant compounds, tocopherols, and phospholipids) was determined in both extracts. The yields of the extracts were different by 32.5 to 53.9%. In the extracts obtained with sc-CO₂ + EtOH (10%), the predominant fatty acids were oleic, palmitic, and linoleic, with considerable levels of desirable fatty acids (DFA), tocopherols, and phospholipids. The nutritional indices showed good values for polyunsaturated and saturated fatty acids (PUFAs/SFAs), above 0.45%. Extracts from larvae meal defatted with SFE showed carotenoids, phenolic compounds, and antioxidant activity. HPTLC and HPLC analyses indicated the presence of amino acids, sugars, phenolics, and organic acids in their composition. This study revealed that the supercritical fluid extraction (SFE) process, or its conditions, can modify the fatty acid composition and the presence of minor bioactive compounds in the obtained extracts. Full article

This study demonstrates a novel methodology for developing a textile-based adsorption sensor via mixed solvent dyeing with aggregation-induced emission (AIE) dyes on recycled fabrics. AIE dyes were incorporated into the fabrics using a mixed solvent dyeing method with a co-solvent mixture of H₂O and organic solvents. This method imparted unique fluorescence properties to fabrics, altering fluorescence intensity or wavelength based on whether the AIE dye molecules were in an isolated or aggregated state on the fabrics. The precise control of the H₂O fraction to organic solvent during dyeing was crucial for influencing fluorescence intensity and sensing characteristics. These dyed fabrics exhibited reactive thermochromic and vaporchromic properties, with changes in fluorescence intensity corresponding to variations in temperature and exposure to volatile organic solvents (VOCs). Their superior characteristics, including a repetitive fluorescence switching property and resistance to photo-bleaching, enhance their practicality across various applications. Consequently, the smart fabrics dyed with AIE dye not only find applications in clothing and fashion design but demonstrate versatility in various fields, extending to sensing temperature, humidity, and hazardous chemicals. Full article

An overview of solvent replacement strategies shows that there is great progress in green chemistry for replacing hazardous di-polar aprotic solvents, such as N,N-dimethylformamide (DMF), 1-methyl-2-pyrrolidinone (NMP), and 1,4-dioxane (DI), used in processing active industrial ingredients (APIs). In synthetic chemistry, alcohols, carbonates, ethers, eucalyptol, glycols, furans, ketones, cycloalkanones, lactones, pyrrolidinone or solvent mixtures, 2-methyl tetrahydrofuran in methanol, HCl in cyclopentyl methyl ether, or trifluoroacetic acid in propylene carbonate or surfactant water (no organic solvents) are suggested replacement solvents. For the replacement of dichloromethane (DCM) used in chromatography, ethyl acetate ethanol or 2-propanol in heptanes, with or without acetic acid or ammonium hydroxide additives, are suggested, along with methanol acetic acid in ethyl acetate or methyl tert-butyl ether, ethyl acetate in ethanol in cyclohexane, CO₂-ethyl acetate, CO₂-methanol, CO₂-acetone, and CO₂-isopropanol. Supercritical CO₂ (scCO₂) can be used to replace many organic solvents used in processing materials from natural sources. Vegetable, drupe, legume, and seed oils used as co-extractants (mixed with substrate before extraction) can be used to replace the typical organic co-solvents (ethanol, acetone) used in scCO₂ extraction. Mixed solvents consisting of a hydrogen bond donor (HBD) solvent and a hydrogen bond acceptor (HBA) are not addressed in GSK or CHEM21 solvent replacement guides. Published data for 100 water-soluble and water-insoluble APIs in mono-solvents show polarity ranges appropriate for the processing of APIs with mixed solvents. When water is used, possible HBA candidate solvents are acetone, acetic acid, acetonitrile, ethanol, methanol, 2-methyl tetrahydrofuran, 2,2,5,5-tetramethyloxolane, dimethylisosorbide, Cyrene, Cygnet 0.0, or diformylxylose. When alcohol is used, possible HBA candidates are cyclopentanone, esters, lactone, eucalytol, MeSesamol, or diformylxylose. HBA—HBA mixed solvents, such as Cyrene—Cygnet 0.0, could provide interesting new combinations. Solubility parameters, Reichardt polarity, Kamlet—Taft parameters, and linear solvation energy relationships provide practical ways for identifying mixed solvents applicable to API systems. Full article