Water Binary Solvent Research Articles

Effect of solvent and temperature on the phase equilibrium behavior of hydroxylamine sulfate in water-ethanol mixed solvents: Solubility and ternary liquid-liquid equilibrium diagram with liquid-liquid equilibrium

The thermodynamic properties of hydroxylamine sulfate (HAS) in binary mixed solvents of water-ethanol were investigated in this work. Experimental results indicated that a temperature above 323.15 K will bring about the occurrence of liquid-liquid phase separation in the water-ethanol-HAS system. Solubility of HAS in water and ethanol-water binary mixed solvents was experimentally determined from 283.15 to 323.15 K under atmospheric pressure (101.3 kPa) by employing a gravimetric method. As the mass fraction of water in the mixed solvent increase, there is an increase in the solubility of HAS. In addition, the solubility of HAS is positively dependent on the temperature. Furthermore, the modified van’t Hoff model, Apelblat model, van’t Hoff − Jouyban − Acree model, and Apelblat − Jouyban − Acree model were used to correlate the experimental solubility of HAS, and the Apelblat model showed the best agreement. Besides, the van't Hoff equation was utilized to evaluate the thermodynamic parameters of HAS in binary solvents, calculation results confirm that these dissolving processes are endothermic and entropy-driving. Ternary phase diagrams with liquid-liquid equilibrium at 324.15, 328.15 and 333.15 K were constructed, and the boundaries of each phase area of the ternary phase diagram were verified at 333.15 K. As for the water-ethanol-HAS system, the temperature has an influence on the phase zone of the ternary phase diagram by affecting solid-liquid phase equilibrium. However, the temperature has no effect on the liquid-liquid phase equilibrium. The nucleation process of oiling-out crystallization of HAS was determined to follow a two-step mechanism: the liquid-liquid phase separation is generated at first, and then nucleation occurred and crystals subsequently grow in the aqueous phase.

Crystallization of citicoline sodium by anti-solvent assisted with ultrasound

Citicoline sodium tend to agglomerate during the crystallization process which can't be well solved by changing some conventional crystallization conditions. To solve this problem, an ultrasonic-assisted crystallization method was developed in this paper. The effects of ultrasound on the crystal metastable zone widths (MSZWs), induction time, crystal habit, and particle size distribution (PSD) were studied experimentally. The dynamic method was used to determine the solubility of Citicoline sodium in ethanol–water binary mixed solvents. The induction time and the MSZWs were measured under ultrasound and silent conditions. Moreover, the crystallization process was optimized using ultrasonic-assisted anti-solvent crystallization method. The influence of ultrasound on crystal habit during the crystallization process could be observed by optical microscope. Ultrasound optimized products can be characterized by scanning electron microscope (SEM), laser particle size analyzer, X-ray powder diffraction and infrared spectroscopy. The experimental results showed that the MSZWs and the induction time could be reduced by the application of ultrasonic irradiation. The agglomeration and crystal habit of Citicoline sodium could be improved by optimizing the crystallization process with ultrasound. After optimization, the mass yield was increased to 95 %, the median particle size DV (50) was about 10 μm and the PSD was narrower.

Solubility measurement, modeling, and solvent effect of m-hydroxyacetophenone in ten pure and binary mixed solvents from T = (289.15–325.15) K

The solubility of m-hydroxyacetophenone (m-HAP) in ten individual solvents (methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, benzene, methyl acetate, ethyl acetate, and water), as well as in methanol + water binary solvents, was measured by gravimetric method at atmospheric pressure of 101.3 kPa. Experimental temperatures range from 289.15 K to 325.15 K. In addition, semi-empirical equations (the modified Apelblat, van't Hoff, λh, Jouyban-Acree-van’t Hoff, KAT-LSER, and the combined equation) and activity coefficient models (Wilson, NRTL, UNIQUAC equation) were used to correlate solubility data of pure and binary mixed solvents. The fitting results demonstrate that nine thermodynamic models involved in the correlation have a good predictive effect for different solvents. Among these models, the modified Apelblat model has the minimum ARD of 1.56% for mono-solvents, and the Wilson equation has the best agreement in methanol + water binary solvents with ARD of 4.73%. Furthermore, the Hansen solubility parameters were applied to analyze the effect of interactions between m-HAP and solvent molecules. The KAT-LSER model was employed to explore the solvent effect for m-HAP in pure and binary solvents. Correlation results indicate that the solvent–solvent interaction represented by cavity term δH accounts for a large proportion of 45.22% among the four interaction forces. Finally, thermodynamic properties (ΔHsolo, ΔGsolo, ΔSsolo) of dissolution in different solvents were calculated by the van’t Hoff equation and the dissolution is an endothermic, non-spontaneous, and enthalpy-driven process.

An environmentally tolerant, highly stable, cellulose nanofiber-reinforced, conductive hydrogel multifunctional sensor

The application of flexible multifunctional sensors based on conductive hydrogels in human health detection has been widely studied. Herein, a facile one-pot method is proposed to prepare ionic conductive hydrogels by dissolving polyvinyl alcohol (PVA), cellulose nanofiber (CNF), and aluminum chloride hexahydrate (AlCl3·6H2O) in a dimethyl sulfoxide (DMSO)/water binary solvent. The resulting ionically-conductive organohydrogels have high stretchability (up to 696%), fast response (130 ms), wide operating temperature (−50 °C to 50 °C), and long-term stability (30 days). The hydrogel sensor exhibits excellent signal sensing capability (human motion and sound detection signals) and cycling stability (1000 cycles) under extreme temperature and long-term storage conditions. Notably, the organohydrogel displays high sensitivity to both compressive deformation and temperature, resulting in multifunctional sensing performance. This work provides a viable approach for the long-term use of hydrogels as wearable devices in extreme environments and daily life.

Adhesive Ionohydrogels Based on Ionic Liquid/Water Binary Solvents with Freezing Tolerance for Flexible Ionotronic Devices

Ionic hydrogels hold substantial promise as soft materials for achieving versatile wearable ionotronics due to the integrated merits of appropriate mechanical properties, excellent conductivity, and good conformability. However, overcoming freezing at subzero temperatures and hindering the evaporation of water are still huge challenges for ionic hydrogels. Herein, a dual-cross-linked ionohydrogel was designed using Al3+ to cross-link with the polymer network through dynamic metal coordination bonds in the water and ionic liquid (IL) binary solvent system, allowing for excellent mechanical properties (∼1 MPa, ∼600%), transparency (>90%), high ionic conductivity (∼12.40 mS cm–1), and robust adhesion, along with the advantages of superior antifreezing and long-term antidehydration properties. These exceptional characteristics inspired us to fabricate dual-responsive sensors, which could simultaneously detect human motion signals and a wide range change of temperatures (from −30 to 40 °C) with an impressive temperature coefficient of resistance (TCR) value (from −0.035 to −0.44 °C–1). More promisingly, benefiting from the superior interfacial adhesion between the poly(dimethylsiloxane) (PDMS) and the ionohydrogels, a triboelectric nanogenerator was assembled with a single-electrode mode that was capable of providing sustainable energy for wearable ionotronic devices even at subzero temperatures. This work opens up an effective strategy to design a multifunctional ionohydrogel, enabling various applications integrated into the single device.

Measurement and Correlation of the Solubility and Thermodynamic Properties of Ribavirin(II) in Nine Pure Solvents and (1-Propanol + Water) Binary Solvents

Measurement and Correlation of the Solubility and Thermodynamic Properties of Ribavirin(II) in Nine Pure Solvents and (1-Propanol + Water) Binary Solvents

Environmentally Compatible Wearable Electronics Based on Ionically Conductive Organohydrogels for Health Monitoring with Thermal Compatibility, Anti-Dehydration, and Underwater Adhesion.

Hydrogel-based electronics have found widespread applications in soft sensing and health monitoring because of their remarkable biocompatibility and mechanical features similar to human skin. However, they are subjected to potential challenges like structural failure, functional degradation, and device delamination in practical applications, especially facing extreme environmental conditions (e.g., abnormal temperature and humidity). To address these, ionically conductive organohydrogel-based soft electronics are developed, which can perform at subzero and elevated temperatures (thermal compatibility) as well as at dehydrated and hydrated environments (hydration compatibility) for extended applications. More specifically, gelatin/poly(acrylic acid-N-hydrosuccinimide ester) (PAA-NHS ester)-based ionic-conductive organohydrogel is synthesized. By introducing a glycerol-water binary solvent system, the gel can maintain mechanical softness in a wide temperature range (from -80 to 60 °C). Besides, excellent conductivity is achieved under various conditions by soaking the gel into lithium chloride anhydrous (LiCl) solution. Strong adhesion with skin, even under water, can be realized by covalent bonds between NHS ester from gel and amino groups from human skin. The excellent performances of LiCl-loaded PAA-based organohydrogel (L-PAA-OH)-based electronics are further demonstrated under freezing and high temperatures as well as underwater conditions, unveiling their promising prospects in wearable health monitoring in various conditions.

Controlling Bicontinuous Structures through a Solvent Segregation-Driven Gel.

The past decade has seen increased research interest in studying bicontinuous structures formed via colloidal self-assembly due to their many useful applications. A new type of colloidal gel, solvent segregation-driven gel (SeedGel), has been recently demonstrated as an effective approach to arrest bicontinuous structures with unique and intriguing properties, such as thermoreversibility, structural reproducibility, and sensitive temperature response. Here, using a model system with silica particles in the 2,6-lutidine/water binary solvent, we investigate the factors controlling the domain size of a SeedGel system by varying the particle concentration, solvent ratio, and quenching protocol. A phase diagram is identified to produce SeedGels for this model system. Our results indicate that by adjusting the sample composition, it is possible to realize bicontinuous domains with well-controlled repeating distances (periodicities). In addition, the effect of quenching rate on the domain size is systematically investigated, showing that it is a very sensitive parameter to control domain sizes. By further heating SeedGel up into the spinodal region, the structure evolution under high temperatures is also investigated and discussed. These results provide important insights into how to control bicontinuous structures in SeedGel systems.

Aggregation of the Dipeptide Leu-Gly in Alcohol-Water Binary Solvents Elucidated from the Solvation Structure for Each Moiety.

The aggregation of a dipeptide, l-leucine-glycine (Leu-Gly), at 100 mmol dm-3 has been observed in 1,1,1,3,3,3-hexafluoroisopropanol (HFIP)-water and 2-propanol (2-PrOH)-water solvents at various alcohol mole fractions, xA, using the dynamic light scattering technique and molecular dynamics (MD) simulations. Leu-Gly was dissolved into the HFIP solvents at the concentration over the entire xA range, while the dipeptide was not dissolved in the 2-PrOH solvents above xA = 0.6. Interestingly, the MD snapshots showed different shapes of Leu-Gly aggregates in the HFIP and 2-PrOH solvents. A linear-shaped aggregate forms in the former; in contrast, a spherical-shaped aggregate is generated in the latter. The solvation structure of each moiety of Leu-Gly in the HFIP and 2-PrOH solvents was observed using experimental and theoretical techniques,1H and 13C NMR, IR, and 19F-1H HOESY measurements and MD simulations. These results gave us the reasons for the different shapes of Leu-Gly aggregates in both solvents. In the HFIP solvents, most of the moieties of the dipeptide are easily solvated by HFIP. This induces the elongated structure of Leu-Gly, leading to the electrostatic interaction between the N- (NH3+ group) and C- (COO- group) terminals of dipeptide molecules. On the other hand, in the 2-PrOH solvents, water molecules that initially solvate the moieties of Leu-Gly, such as the N- and C-terminals and the peptide linkage, are not easily eliminated even as the xA is close to 0.6. The water molecules can bridge such moieties of Leu-Gly to form spherical-shaped aggregates. The diffusion coefficients of Leu-Gly in both alcohol-water binary solvents were experimentally determined by NMR DOSY to estimate the geometries of the aggregates in the solvents. The sizes of Leu-Gly aggregates obtained by DOSY for both solvent systems were consistent with those estimated from the MD snapshots.

Solubilities of Oleanolic Acid and Ursolic Acid in Different Organic Solvents and 2-Propanol + Water Binary Solvent Mixtures at Different Temperatures: Experimental Measurement and Modeling

The solubilities of oleanolic acid and ursolic acid in 1-butanol, methyl isobutyl ketone, methyl tert-butyl ether, and 2-propanol + water binary solvent systems at different temperatures were deter...

Solubility measurement and thermodynamic properties of sulfamonomethoxine in pure solvents and sulfamonomethoxine hydrate in acetone + water binary solvent at different temperature

The experimental solubility of sulfamonomethoxine in six different pure solvents (methanol, ethanol, 1-propanol, l-butanol, ethyl acetate and acetone) and sulfamonomethoxine hydrate in acetone + water mixture solvents were measured from 294.55 K to 362.15 K by a laser dynamic method under atmospheric pressure. Experimental results indicated that the solubility data of sulfamonomethoxine increased with temperature increasing in pure solvents and the solubility followed this order: acetone > methanol > ethanol > ethyl acetate > 1-propanol > 1-butanol, but solubility in ethyl acetate was not affected significantly by temperature. In acetone + water mixture solvent, the solubility of sulfamonomethoxine hydrate increased with temperature and the acetone concentration. Thermodynamic equations were applied to correlate solubility data of sulfamonomethoxine and sulfamonomethoxine hydrate including the modified Apelblat equation, λh equation, Wilson equation, NRTL equation, Van’t Hoff-Jouyban Acree equation and modified Apel-Jouyban-Acree equation. Furthermore, thermodynamic properties ΔGd, ΔHd and ΔSd of sulfamonomethoxine and sulfamonomethoxine hydrate in dissolution process were obtained and discussed with the modified Van’t Hoff equation and Gibbs equation.

MXene‐Based Conductive Organohydrogels with Long‐Term Environmental Stability and Multifunctionality

AbstractConductive hydrogels are promising interface materials utilized in bioelectronics for human–machine interactions. However, the low‐temperature induced freezing problem and water evaporation‐induced structural failures have significantly hindered their practical applications. To address these problems, herein, an elaborately designed nanocomposite organohydrogel is fabricated by introducing highly conductive MXene nanosheets into a tannic acid‐decorated cellulose nanofibrils/polyacrylamide hybrid gel network infiltrated with glycerol (Gly)/water binary solvent. Owing to the introduction of Gly, the as‐prepared organohydrogel demonstrates an outstanding flexibility and electrical conductivity under a wide temperature spectrum (from −36 to 60 °C), and exhibits long‐term stability in an open environment (>7 days). Additionally, the dynamic catechol‐borate ester bonds, along with the readily formed hydrogen bonds between the water and Gly molecules, further endow the organohydrogel with excellent stretchability (≈1500% strain), high tissue adhesiveness, and self‐healing properties. The favorable environmental stability and broad working strain range (≈500% strain); together with high sensitivity (gauge factor of 8.21) make this organohydrogel a promising candidate for both large and subtle motion monitoring.

Solubility measurement, thermodynamic correlation and molecular simulations of uracil in (alcohol + water) binary solvents at (283.15–318.15) K

The solubility of uracil in binary solvent mixtures, including (methanol + water), (ethanol + water) and (isopropanol + water), was determined from 283.15 K to 318.15 K by the ultraviolet spectroscopic method. It was shown by experiments that when the composition of solvent is constant, the solubility of uracil increases with the temperature. And the solubility of uracil in the binary solvent mixtures ranges as: (isopropanol + water) > (ethanol + water) > (methanol + water). Under isothermal conditions, as the mole fraction of organic solvent increases, the solubility of uracil increases first and then decreases gradually. To further verify the observed phenomena, the molecular simulations, including molecular electrostatic potential surface, Hirshfeld surface analysis and solvation free energy were provided. Besides, the modified Apelblat equation, λh model, CNIBS/R-K model, Jouyban-Acree model and NRTL model, were selected to correlate the experimental data, respectively. The results indicated that all selected thermodynamic models have good accuracy. Furthermore, the standard thermodynamic properties of the mixtures, including Gibbs energy, entropy and enthalpy were calculated and discussed, which indicated that the dissolution of the uracil in these three binary solvent mixtures is spontaneous and endothermic. All the results presented in this paper have some reference value to the further study of uracil.

Measurement and Correlation of Solubility and Thermodynamic Properties of Fluoxetine Hydrochloride in 15 Pure Solvents and a Methanol + Water Binary Solvent System

The solubilities of fluoxetine hydrochloride (FH) in pure solvents including methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, s-butanol, n-pentanol, i-pentanol, acetone, 2-butanone,...

Further comments on “Experimental measurements, equilibrium study and model correlation of methyl paraben in ethanol and methanol aqueous solutions from = (293.15 to 323.15) K”

The experimental solubility data of methyl paraben in ethanol + water and methanol + water binary solvent mixtures at temperature range from (293.15 to 323.15) K have carefully been reanalyzed and some recommendations were proposed. In addition, preferential solvation analyses based on the inverse Kirkwood-Buff integrals show that this compound is preferentially solvated by water in water-rich mixtures in both binary systems but preferentially solvated by the cosolvent in the composition region of 0.24 < x1 < 1.00 for ethanol + water mixtures and the composition region of 0.31 < x1 < 1.0 for methanol + water mixtures.

Cooperative dissociation of J-aggregates into monomers in the 2-isobutoxyethanol/water binary solvent with the lower critical solution temperature

J-aggregates are supramolecular assemblies with characteristic optical properties originating from their excitonic interactions and have applications in fluorescence biosensing and artificial light-harvesting systems. Herein, we investigated the formation and dissociation of the J-aggregates of 1,1′-dioctadecyl-3,3,3′,3′-tetramethylindocarbocyanine perchlorate (DiIC18(3)) in 2-isobutoxyethanol (iBE)/water (W) binary solvents with the lower critical solution temperature (LCST). We found that DiIC18(3) forms J-aggregates in iBE/W binary solvents with compositions of 12/88–17/83% (v/v). By measuring the temperature dependence of the absorption spectra, we found that the J-aggregates dissociate into monomers cooperatively before the iBE/W binary solvents show the liquid–liquid phase separation. The hydrophobicity of the iBE/W binary solvents was evaluated by measuring the fluorescence spectra of 1-Anilinonaphtharene-8-sulfonic acid (1,8-ANS), whose fluorescence peak wavelength reflects the hydrophobicity of the solvents. The J-aggregates were found to dissociate cooperatively when the iBE/W binary solvents reached a constant hydrophobicity, although the composition of the iBE/W binary solvents was different. The J-aggregates precipitated without dissociation in binary solvents without the LCST. We propose that concentration fluctuation of iBE/W binary solvents promotes the cooperative dissociation of the DiIC18(3) J-aggregates.

Key Factors Determining Efficiency of Liquid-Liquid Extraction: Implications from Molecular Dynamics Simulations of Biphasic Behaviors of CyMe4-BTPhen and Its Am(III) Complexes.

CyMe4-BTPhen (2,9-bis(5,5,8,8-tetramethyl-5,6,7,8-tetrahydro-1,2,4-benzotriazin-3-yl)-1,10-phenanthroline, denoted as L) has been considered as a promising extractant in lanthanide(III)/actinide(III) separation. Vast endeavors in its application put forward a compelling need on the understanding of the underlying mechanism in the liquid-liquid extraction. To address the issue of its dynamics in biphasic systems, we carried out molecular dynamics (MD) simulations of L and its complexes with a heavy f-block metal ion, americium(III) (Am3+) in "oil"/water binary solvents. Two types of organic phases have been considered, differing in the presence of octanol in the bulk n-dodecane or not, and the distribution of the solutes and their interfacial behaviors have been investigated. Two of the key factors that determine the efficiency of a liquid-liquid extraction protocol were delineated and discussed, that is, the appropriate ligand to enhance the lipophilicity of AmL complexes and appropriate way to form ion pairs to minimize the attraction between the complexes and aqueous phase. The simulations showed that the charge states of both ligand and AmL complexes were strongly correlated with their phase behavior, and the migration of neutral species was driven by van der Waals interactions while that of charged species by electrostatic interactions, indicating stronger lipophilicity of the former than the latter. The presence of octanol facilitated the migration of the ligand from the interface to the organic phase via hydrogen bond between its polar head and the ligand or the AmL complexes and constituted a polar core in the organic phase. This work bridged the widely used liquid-liquid extraction technique in chemistry to a fundamental chemical concept, that is, minimization of hydrophilicity and maximization of lipophilicity to facilitate phase transfer from the aqueous phase to the organic phase, and is expected to improve the understanding of dynamics of ligands and their complexes with metal ions and to contribute to the development of efficient protocols for phase transfer of target species.

The advantage of alcohol–calcium method on the formation and the stability of vaterite against ethanol–water binary solvent method

Abstract

Solubility determination and correlation for azithromycin monohydrate and dihydrate in solvent mixtures

The solubility of azithromycin monohydrate in binary solvent mixtures (ethanol + water and propanol + water) was studied by a static method with a temperature range from 283.15 K to 323.15 K under atmospheric pressure. Besides, azithromycin dihydrate in acetone + water binary solvent mixtures was reported with temperature ranging from 283.15 K to 323.15 K. Results showed that the solubility of azithromycin monohydrate and dihydrate in binary solvent mixtures all increased with temperature and the content of organic solvents. The solubility data in binary solvent mixtures were correlated by van't Hoff-Jouyban-Acree model, Apelblat-Jouyban-Acree model, Ma model and Sun model, and all models could be used to correlate the solubility of azithromycin monohydrate and dihydrate in the solvent mixtures. All the result mentioned in this study could help purify azithromycin monohydrate and dihydrate.

Fabrication of Orange-Emitting Organic Nanoparticle-Protamine Conjugate: Fluorimetric Sensor of Heparin.

Among the diverse sensing techniques, fluorimetric detection dominates over the other methods because of its rapid signaling, high selectivity and sensitivity, and operational simplicity. This present article delineates fabrication of a fluorescent organic nanoparticle-protamine (FONP-Pro) conjugate for selective and sensitive detection of heparin simply by exploitation of the aggregation-induced emission (AIE) property of the FONPs. Naphthalene diimide-based bola-type amphiphilic molecules (NDI-1) comprise a naphthyl residue and a 3-aminopyridyl unit at both terminals, forming organic nanoparticles in a dimethyl sulfoxide-water binary solvent mixture, and exhibited AIE through excimer formation. The presence of naphthyl residue in the molecular backbone facilitates the intramolecular charge transfer to generate orange-emitting (λem = 594 nm) AIE-luminogen (AIE-gen). The aminopyridine residues within NDI-1 induced negative surface charge on NDI-1 FONPs, which facilitated interaction with positively charged protamine (Pro) to construct FONP-Pro conjugates. Formation of this NDI-1 FONP-Pro conjugate through the interaction between Pro and FONP drastically reduced the orange emission intensity (fluorescence off) of the AIE-gens. Interestingly, addition of heparin to this FONP-Pro conjugate turned on the fluorescence signal of FONPs through unwinding of the Pro from the FONP surface because of a strong binding affinity between heparin and Pro. Formation of the FONP-Pro conjugate and fluorimetric sensing of heparin was investigated by monitoring the change in emission behavior of NDI-1 FONPs. Also, the heparin-sensing was found to be highly selective against many other biomolecules including proteins, enzymes, and DNA. Hence, a selective and efficient heparin sensor (FONP-Pro) was developed having a limit of detection of 12 nM simply by utilizing the fluorescence "turn-off" and "turn-on" mechanism of NDI-1 FONP.