Cosolvent Systems Research Articles

Colloidal synthesis of 1-D van der Waals material Nb2Se9: study of synergism of coordinating agent in a co-solvent system.

Low-dimensional Nb2Se9 nanocrystals were synthesised through a simple one-pot colloidal synthesis with C18 organic solvents (octadecane, oleylalcohol, octadecanethiol, octadecene (ODE), and oleylamine (OLA)) of varied terminal functional groups. The solvent with high reducing power facilitated the nucleation of the nanoparticle, lowering threshold concentration and broadening the concentration spectrum. As a solvent, reducing agent, and capping agent, ODE functions as a primary factor in the synthesis of high-quality Nb2Se9 nanorods. We further discuss the unique adhesion role of ODE under the co-solvent system and demonstrate morphology control through synergism between ODE and OLA, verified by the electrochemical measurements.

How cryoprotectants work: hydrogen-bonding in low-temperature vitrified solutions.

Dimethyl sulfoxide (DMSO) increases cell and tissue viability at low temperatures and is commonly used as a cryoprotectant for cryogenic storage of biological materials. DMSO disorders the water hydrogen-bond networks and inhibits ice-crystal growth, though the specific DMSO interactions with water are difficult to characterize. In this study, we use a combination of Fourier Transform infrared spectroscopy (FTIR), molecular dynamics simulations, and vibrational frequency maps to characterize the temperature-dependent hydrogen bonding interactions of DMSO with water from 30 °C to −80 °C. Specifically, broad peaks in O–D stretch vibrational spectra of DMSO and deuterated water (HDO) cosolvent systems show that the hydrogen bond networks become increasingly disrupted compared to pure water. Simulations demonstrated that these disrupted hydrogen bond networks remain largely localized to the first hydration shell of DMSO, which explains the high DMSO concentrations needed to prevent ice crystal formation in cryopreservation applications.

Equilibrium leaching of selected ultraviolet stabilizers from plastic products

Despite the importance of (micro)plastics in the release of plastic additives, the leaching mechanism of organic plastic additives from various plastic materials is poorly understood. In this study, the equilibrium leaching of five highly hydrophobic ultraviolet (UV) stabilizers (UV326, UV327, UV328, UV329, and UV531) from three plastics (low-density polyethylene (LDPE), polyethylene terephthalate (PET), and polystyrene (PS)), was investigated employing acetonitrile-water cosolvent systems. Their extrapolated water solubilities were in the 0.15–0.54 μg L−1 range, limiting their transport as “dissolved” in water and (micro)plastics are likely those particulate carriers. The equilibrium leaching of UV stabilizers from plastics was better explained by the Flory-Huggins model incorporating the nonideal behavior caused by the size disparity between UV stabilizers and polymer materials and their compatibility. Specifically, leaching of UV stabilizers from LDPE showed a positive deviation from Raoult’s law, whereas slight negative deviations were observed in PET and PS. In addition, the equilibrium concentration of the benzotriazoles in LDPE increased linearly with the volume fraction up to only 0.4%. These observations could be explained by the unfavorable interactions of UV stabilizers with polyethylene, indicating that polymer type should be also important when evaluating the fate of hydrophobic additives. Because equilibrium distribution of additives between (micro)plastics and water is crucial for evaluating the fate and transport of hydrophobic plastic additives, further studies on the leaching equilibrium of various additives from different plastic materials are necessary.

Solubility of Sulfamethazine in the Binary Mixture of Acetonitrile + Methanol from 278.15 to 318.15 K: Measurement, Dissolution Thermodynamics, Preferential Solvation, and Correlation

Solubility of sulfamethazine (SMT) in acetonitrile (MeCN) + methanol (MeOH) cosolvents was determined at nine temperatures between 278.15 and 318.15 K. From the solubility data expressed in molar fraction, the thermodynamic functions of solution, transfer and mixing were calculated using the Gibbs and van ’t Hoff equations; on the other hand, the solubility data were modeled according to the Wilson models and NRTL. The solubility of SMT is thermo-dependent and is influenced by the solubility parameter of the cosolvent mixtures. In this case, the maximum solubility was achieved in the cosolvent mixture at 318.15 K and the minimum in pure MeOH at 278.15 K. According to the thermodynamic functions, the SMT solution process is endothermic in addition to being favored by the entropic factor, and as for the preferential solvation parameter, SMT tends to be preferentially solvated by MeOH in all cosolvent systems; however, , so the results are not conclusive. Finally, according to mean relative deviations (MRD%), the two models could be very useful tools for calculating the solubility of SMT in cosolvent mixtures and temperatures different from those reported in this research.

Inkjet-Printed Electron Transport Layers for Perovskite Solar Cells.

Inkjet printing emerged as an alternative deposition method to spin coating in the field of perovskite solar cells (PSCs) with the potential of scalable, low-cost, and no-waste manufacturing. In this study, the materials TiO2, SrTiO3, and SnO2 were inkjet-printed as electron transport layers (ETLs), and the PSC performance based on these ETLs was optimized by adjusting the ink preparation methods and printing processes. For the mesoporous ETLs inkjet-printed from TiO2 and SrTiO3 nanoparticle inks, the selection of solvents for dispersing nanoparticles was found to be important and a cosolvent system is beneficial for the film formation. Meanwhile, to overcome the low current density and severe hysteresis in SrTiO3-based devices, mixed mesoporous SrTiO3/TiO2 ETLs were also investigated. In addition, inkjet-printed SnO2 thin films were fabricated by using a cosolvent system and the effect of the SnO2 ink concentrations on the device performance was investigated. In comparison with PSCs based on TiO2 and SrTiO3 ETLs, the SnO2-based devices offer an optimal power conversion efficiency (PCE) of 17.37% in combination with a low hysteresis. This work expands the range of suitable ETL materials for inkjet-printed PSCs and promotes the commercial applications of inkjet printing techniques in PSC manufacturing.

Sulfated zirconia catalysts supported on mesoporous Mg-SBA-15 with different morphologies for highly efficient conversion of fructose to 5-hydroxymethylfurfural

In this work, the novel acid-base bi-functional mesoporous SBA-15 catalysts with four kinds of morphologies were synthesized by Mg incorporated and sulfated zirconia (SZ) grafted. The introduction of Mg to mesoporous SBA-15 materials significantly improves the strength of the base. And the supported SZ group exhibit effective Brønsted/Lewis acid strength. The physical and chemical properties of the prepared materials were systematically analyzed by the characterization tests of SEM, TEM, XRD, N 2 adsorption-desorption of, FT-IR, TGA, XPS, NH 3 /CO 2 -TPD and in-suit PY-IR. The obtained catalysts of SZ@Mg-SBA-15 could be applied to the fructose conversion into 5-hydroxymethylfurfural (5-HMF) with the co-solvent system of iPrOH/DMSO ( v / v = 9:1). 5-HMF was achieved under the optimal reaction condition with the highest yield of 98.6%. The result shows that the reaction of fructose dehydration into 5-HMF could be caused by the combination of Brønsted acid site and basic site. This work developed reaction system could avoid the large use of environmentally dangerous solvents, and provides a new economical and feasible method for the large-scale conversion of fructose biomass. • Mesoporous SZ@Mg-SBA-15 catalysts were successfully synthesized. • The acid-base bifunctional sites showed synergistic effects in catalytic activity. • The highest 5-HMF yields of 98.6% can be obtained from fructose. • The developed iPrOH/DMSO co-solvent has a minimal environmental impact. • The prepared catalyst can be reused without significant loss of activity.

Cytotoxicity and Antimicrobial Action of Methyl and Butyl Paraben in Different Complex Co-Solvent Systems

Cytotoxicity and Antimicrobial Action of Methyl and Butyl Paraben in Different Complex Co-Solvent Systems

Catalytic Synthesis of the Biofuel 5-Ethoxymethylfurfural (EMF) from Biomass Sugars

A new generation of bioplatform molecule 5-ethoxymethylfurfural (EMF) has excellent energy density and combustion performance, which makes it a potential fuel additive. This article reviews the factors that affect the production of EMF from different feedstocks, including platform compounds, monosaccharides, polysaccharides, and raw lignocellulosic biomass. Focus is placed on discussing the catalytic efficiency with pros and cons of different acid catalysts, including homogeneous catalysts (i.e., liquid acids and metal salts), heterogeneous catalysts (i.e., zeolites, heteropolyacid-based hybrids, and SO3H-based catalysts), ionic liquids, mixed acid catalysts, and deep eutectic solvents (DESs). Except for the commonly used ethanol solvent, this review also summarizes the influence of the cosolvent system (e.g., ethanol/dimethylsulfoxide (DMSO), ethanol/tetrahydrofuran (THF), and ethanol/γ-valerolactone (GVL)) on the EMF yield.

Modulation of DNAzyme Activity via Butanol Dehydration.

Understanding the activity of biomolecules in cosolvent systems is important for catalysis, separation and developing biosensors. The majority of previously studied solvents are either phase separated with water or miscible with water. Butanol was recently used to extract water for the conjugation of DNA to gold nanoparticles. In this work, the effect of butanol on the activity of a few RNA-cleaving DNAzymes was studied. A 130-fold improvement in sensitivity for the Na+ -specific EtNa DNAzyme was observed, and butanol also improved the activity of another Na+ -specific DNAzyme, NaA43T by a few folds. However, when divalent metal ions were used for both EtNa and 17E DNAzymes, the activity was inhibited. A main driven force for enhanced DNAzyme activity is the concentration effect due to butanol dehydration. This study provides insights into the interplay between DNA, metal ions and organic solvents, and such an understanding might be useful for developing sensitive biosensors.

Supramolecular-induced 2.40 V 130 °C working-temperature-range supercapacitor aqueous electrolyte of lithium bis(trifluoromethanesulfonyl) imide in dimethyl sulfoxide-water

Increasing the electrochemical stability window and working temperature range of supercapacitor aqueous electrolyte is the major task in order to advance aqueous electrolyte-based supercapacitors. Here, a supramolecular induced new electrolyte of lithium bis(trifluoromethanesulfonyl) imide (LiTFSI) in dimethyl sulfoxide (DMSO) and water co-solvent system is proposed. Adjusting the coordination structure among LiTFSI, DMSO, and water in the electrolyte via supramolecular interactions results in its high ionic conductivity, low viscosity, wide electrochemical stability window, and large working temperature range. The new electrolyte-based supercapacitors can work in 2.40 V working potential and 130 °C working-temperature range from −40 to 90 °C. The devices exhibit good electrochemical performances, especially the energy density over 21 Wh kg−1, which is much higher than that with traditional aqueous electrolytes (<10 Wh kg−1). The work paves a way to develop high-performance aqueous electrolytes for supercapacitors.

Development of Aqueous Formulation Containing the Extracted Mangiferin

Mangiferin, a polyphenol of C-glycosylxanthone, exhibits various bioactivities with poor aqueous solubility. It is known as a potent antioxidant, which leads to remarkable UV protection and anti-aging properties. Mangiferin can be found in many plant species, among which the mango leaf is one of the primary sources. From our study, the extraction yield of mangifein obtained from the leaves of Mangifera indica L. variety Nam Doc Mai was 3.17% with 95.02% ± 0.064 purity (HPTLC analysis). The solubility of mangiferin in the studied pure solvents arranging in descending order were ethoxydiglycol, dimethyl isosorbide, polyethylene glycol 400, polyethylene glycol 600, propylene glycol, dipropylene glycol, glycerin, isopentyldiol, methanol, ethanol and water, whereas the addition of the solvent in water could increase the aqueous solubility of mangiferin. In several cases, the solubility was apparently higher than that dissolved in its pure solvent state. The log-linear solubility model for the cosolvent system was used to calculate the volume fractions of the selected solvents needed to solubilize mangiferin content at the twenty times of the IC50 against DPPH radicals. In conclusion, the developed aqueous formulation contained 0.5% w/v of mangiferin and 20% w/v of polyethylene glycol 600 or dipropylene glycol as a solubilizer in water.

Fractionation of Lignin with Decreased Heterogeneity: Based on a Detailed Characteristics Study of Sequentially Extracted Softwood Kraft Lignin

Industrial lignin fractionation is attracting increasing interest due to its enormous potential in the development of high value-added materials. However, the widely reported fractionation approaches are primarily focused on the separation of fractions with a low polydispersity index (PDI). In this study, based on the detailed characteristic examination of carefully sequential-extracted softwood Kraft lignin fractions, a novel method to isolate lignin fraction with decreased heterogeneity (LGF-dh), was established in consideration of impurities, elemental composition, molar mass distribution, carbohydrate content, functional hydroxyl content, and the content of lignin-relevant aromatic units. To characterize the mentioned properties, an elemental analyzer, SEC-MALS, GC–MS, GC-FID, Py/GC–MS, 31P-NMR, and HSQC-NMR were used to compare the differences of the sequential lignin fractions that were obtained by methyl tert-butyl ether (MTBE), ethyl acetate (EtOAc), ethanol (EtOH), methanol (MeOH), acetone, and dioxane. Moreover, a practical and feasible three-step extraction process was proposed to separate the low heterogeneity lignin fraction from industrial lignin according to the different solubilities of each fraction in the green cosolvent system of EtOH/water, MeOH/water, and acetone/water. Overall, this work presented a comprehensive study on the properties of softwood lignin as well as proposed a feasible and convenient method to reduce the heterogeneity of lignin, which would promote its valorization.

Microcrystalline Cellulose-Blended Polyethersulfone Membranes for Enhanced Water Permeability and Humic Acid Removal.

A novel polyethersulfone (PES)/microcrystalline cellulose (MCC) composite membrane for humic acid (HA) removal in water was fabricated using the phase inversion method by blending hydrophilic MCC with intrinsically hydrophobic PES in a lithium chloride/N,N-dimethylacetamide (LiCl/DMAc) co-solvent system. A rheological study indicated that the MCC-containing casting solutions exhibited a significant increase in viscosity, which directly influenced the composite membrane’s pore structure. Compared to the pristine PES membrane, the composite membranes have a larger surface pore size, elongated finger-like structure, and presence of sponge-like pores. The water contact angle and pure water flux of the composite membranes indicated an increase in hydrophilicity of the modified membranes. However, the permeability of the composite membranes started to decrease at 3 wt.% MCC and beyond. The natural organic matter removal experiments were performed using humic acid (HA) as the surface water pollutant. The hydrophobic HA rejection was significantly increased by the enhanced hydrophilic PES/MCC composite membrane via the hydrophobic–hydrophilic interaction and pore size exclusion. This study provides insight into the utilization of a low-cost and environmentally friendly additive to improve the hydrophilicity of PES membranes for efficient removal of HA in water.

Transparent and UV-absorbing nanocellulose films prepared by directly dissolving microwave liquefied bamboo in TBAA/DMSO co-solvent system

Bamboo is a potential resource to produce renewable materials with replacement of plastic. In this study, cellulose-rich bamboo fibers and parenchyma with partial lignin (4–10 %) retained were prepared from microwave liquefaction, thereafter nanocellulose with uniform diameter (less than 10 nm) distribution were obtained by directly dissolving the cellulose-rich bamboo cells in TBAA/DMSO system. By solvent-casting, transparent nanocellulose films with efficient UV-absorbing ability especially the excellent UVA (82 %) and UVB (99 %) absorbing performance were fabricated. The films showed homogeneous network structure and had good tensile strength (15−25 MPa). Changes in cellulose crystallinity structure was observed during the film preparation process. Results also showed that the lignin in the cellulose-rich bamboo could distribute uniformly in the nanocellulose films and had effect on the film formation, UV-absorbing ability and physical-mechanical properties. Overall, microwave liquefaction coupling with TBAA/DMSO dissolving system could be selected as a facile and simple method to produce transparent nanocellulose films with UV-absorbing property.

Electrospinnable, Neutral Coacervates for Facile Preparation of Solid Phenolic Bioadhesives.

Liquid-liquid phase separation in an aqueous polymer solution is a unique physicochemical phenomenon, and the material present in the dense bottom layer is called a coacervate. A partial degree of water exclusion during coacervate formation often results in adhesive properties. The high viscosity makes coacervates incompatible with electrospinning processes. Coacervates can be electrospinnable only when the viscosity level of coacervates is adjusted. Electrospinning of coacervates results in a liquid-to-solid phase transition, addressing a long-term stability issue of coacervates. The preserved electrospun membranes can always be reconverted to a coacervate state by dissolution. Herein, we fabricate a spinnable coacervate solution using cosolvents. For neutral, hydrogen bond-dominated coacervates, such as those composed of poly(vinyl alcohol) (PVA) and phenolic tannic acid (TA), the use of a polar cosolvent system such as methanol-water results in an electrospinnable coacervate solution. The spun PVA-TA porous mats are a physicochemically stable solid, and the materials are converted back to an adhesive state upon wetting with body fluid. Considering the emerging studies related to coacervate adhesives, this study suggests that electrospinning a coacervate solution can be a strategy to dramatically increase the material stability and functionality.

Saturated Solubility Determination and Correlation of 2-Methyl-4-Methylamino-6-Methoxy-1,3,5-Triazine in Several Aqueous Cosolvent Systems from 278.15 to 323.15 K

Saturated Solubility Determination and Correlation of 2-Methyl-4-Methylamino-6-Methoxy-1,3,5-Triazine in Several Aqueous Cosolvent Systems from 278.15 to 323.15 K

Competitive adsorption of methanol co-solvent and dioctyl phthalate on functionalized graphene sheet: Integrated investigation by molecular dynamics simulations and quantum chemical calculations

Hypothesis.Organic co-solvents, which are universally employed in adsorption studies of hydrophobic organic chemicals (HOCs), can inhibit HOC adsorption by competing for active sites on the adsorbent. The adsorbent structure can influence co-solvent interference of HOC adsorption; however, this effect remains unclear, leading to an incomplete understanding of the adsorption mechanism. Experiments.In this study, dioctyl phthalate (DOP) was used to investigate competitive adsorption on functionalized graphene sheet in a water–methanol co-solvent system through molecular dynamics simulations and quantum chemical calculations. Findings.The simulations showed that the functional groups in the graphene defects had a strong adsorption affinity for methanol. The adsorbed methanol occupied a large number of active sites at the graphene center, thereby weakening DOP adsorption. However, the methanol adsorbed at the graphene edges could not compete with DOP for the active sites. –COOH had the strongest binding affinity for methanol among the functional groups and thus predominantly controlled the interaction between graphene and methanol. This study makes an innovative contribution toward understanding the competitive adsorption of methanol and DOP on functionalized graphene sheet, especially in visualizing the competition for active sites, and provides theoretical guidance for the removal of HOCs and practical application of graphene.

Solubility modeling, Hansen solubility parameter, solvation thermodynamics and enthalpy–entropy compensation of 5-chlorooxine (form I) in several aqueous cosolvent solutions

The current contribution was dedicated to solubility profile, solvation behavior, and inter- and intramolecular interactions for the binary systems formed by 5-chlorooxine (I) in aqueous solutions of ethanol, N-methyl-2-pyrrolidinone (NMP), isopropanol and N,N-dimethylformamide (DMF) together with numerous computational approach. A shake-flask method conducted all experiments under local pressure p = 101.2 kPa over temperatures ranging from 278.15 to 323.15 K. For each cosolvent system, the highest equilibrium solubility of 5-chlorooxine (I) was recorded in neat cosolvent at temperature of T = 323.15 K; and the lowest one, in neat solvent of water at 278.15 K. The solubility performance was investigated by the use of the Hansen solubility parameter and extended Hildebrand solubility approach. Numerous models, e.g. mixture response surface, Jouyban–Acree, modified Wilson and Jouyban–Acree–van’t Hoff acceptably correlated the obtained mole fraction solubility with relative average deviations (RAD) no greater than 7.25 %. The relative contribution of solute–solvent and solvent–solvent interactions to equilibrium solubility variation of 5-chlorooxine (I) at the temperature of 298.15 K was analyzed quantitatively by employing the linear solvation energy relationships, indicating that the dipolarity-polarizability and solubility parameter of solvent systems were predominantly responsible for the 5-chlorooxine (I) solubility. The solvation behavior was inspected by the extended Hildebrand solubility approach applied to the solubility data at 298.15 K, gaining RAD of no more than 3.15 %. In addition, preferential solvation of 5-chlorooxine (I) was quantitatively analyzed by the method of inverse Kirkwood–Buff integrals in terms of some available solution properties. The positive preferential solvation parameters for 5-chlorooxine (I) in intermediate and cosolvent-rich solutions suggests that the solute 5-chlorooxine (I) is preferentially solvated by cosolvents. It is speculated that 5-chlorooxine (I) performs as a Lewis acid behavior with cosolvent molecules in above composition districts. The dissolution of 5-chlorooxine (I) in all aqueous solution systems was entropy-driven and endothermic process.

Sustainable Production of Glycolipids by Biocatalyst on Renewable Deep Eutectic Solvents

Glycolipids have become an ecofriendly alternative to chemically obtained surfactants, mainly for the cosmetic, pharmaceutical, and food industries. However, the sustainable production of these compounds is still challenging, because: (i) water is a recognized inhibitor, (ii) multiphases make the use of cosolvent reaction medium necessary, and (iii) there are difficulties in finding a source for both starting materials. This study used sugars and lipids from peach palm fruit shells or model compounds as substrates to synthesize glycolipids on five different renewable deep eutectic solvents (Re-DES) alone or with a cosolvent system. Substrate conversions up to 24.84% (so far, the highest reported for this reaction on DES), showing (1) the non-precipitation of glucose in the solvent, (2) emulsification and (3) low viscosity (e.g., more favorable mass transfer) as the main limiting factors for these heterogeneous enzymatic processes. The resulting conversion was reached using a cosolvent system Re-DES:DMSO:t-butanol that was robust enough to allow conversions in the range 19–25%, using either model compounds or sugar and fatty acid extracts, with free or immobilized enzymes. Finally, the characterization of the in-house synthesized glycolipids by surface tension demonstrated their potential as biosurfactants, for instance, as an alternative to alcohol ethoxylates, industrially produced using less sustainable methods.

Simultaneous representation of thermodynamic properties and viscosities of ILs/DESs+co-solvent systems by Eyring-NRTL model

In this work, the nonrandom two-liquid model (NRTL) was coupled with the Eyring's absolute rate theory (the Eyring-NRTL model), to study thermodynamic properties and viscosities simultaneously with one set of parameters, and ten non-aqueous mixtures containing ionic liquids (ILs)/deep eutectic solvents (DESs) were chosen in the study as the first step. In model parameterizing, three strategies were investigated, which were viscosity as the input only, enthalpy with/without vapor pressure as the inputs, and enthalpy and viscosity as inputs, respectively. The investigation shows that it is possible to represent thermodynamic and kinetic properties simultaneously. Furthermore, the viscosity can be predicted using the model with reasonable parameters determined from the excess enthalpy, and incorporating vapor pressures and limited viscosity data in parameterizing can further improve the model performance on the viscosity. For the first time, the thermodynamic model was coupled with the Eyring's theory to study the systems of (IL/DES + molecular solvent), how to obtain the model parameters was clarified, and the possibility and reliability of the used model in representing thermodynamic and kinetic properties were illustrated and discussed.