Binary Solutions Of Water Research Articles

An insight into liquid water networks through hydrogen bonding halide anion: Stimulated Raman scattering

We have studied the interaction between water molecules and halide anions and acquired the influence of concentration by the spontaneous Raman spectrum. The results agreed well with the previous researches. To explore further, the stimulated Raman scattering of a halide–water binary solution is measured to study the nature of the hydrogen bonding between water molecules and halogen anions. Under the effect of laser-induced plasma, the OH stretching vibration spectra of aqueous solutions of halogen ions pretty exhibit different trend compared with that of spontaneous Raman spectrum. The frequency shifts of water OH vibration show different values and directions with adding different halide anions. The red shift of F−– and Cl−–water molecule clusters is due to the process of charge transfer, whereas the blue shift of Br−– and I−–water molecule cluster is due to polarization effect without charge transfer. The results demonstrate that F− and Cl− slightly weaken the hydrogen bond (HB), whereas Br− and I− enhance HB in the water cluster. The decrease of concentration of halogen ions aqueous solution can weaken the effect on the HB.

Biobutanol separation from ABE model solutions and fermentation broths using a combined adsorption–gas stripping process

AbstractBACKGROUNDButanol is considered a promising sustainable biofuel to partly replace petroleum‐based fuels. However, to become an economically viable biofuel, some challenges need to be overcome in the biobutanol production process such as the low final product concentration caused by product toxicity to the microorganism. Few separation techniques have been proposed to extract biobutanol in situ or ex situ from dilute fermentation broths. In this investigation, the combination of gas stripping and adsorption has been studied experimentally as a process to effectively separate butanol from dilute model solutions and fermentation broths using the advantages of both separation techniques.RESULTSResults showed that the butanol adsorption capacity of activated carbon F‐400 was 261 mg g−1, for a stripped gas stream from butanol–water binary solution with an initial liquid phase composition of 15 g L−1 butanol, which ended up having a vapour phase composition of 5.8 mg L−1 after gas stripping. This capacity is relatively high compared with the values reported in the literature. Butanol adsorption capacities for a stripped gas stream in equilibrium with ABE model solutions (5.1 mg L−1) and fermentation broths (2.3 mg L−1) for this adsorbent (211.6 and 219.8 mg g−1, respectively), were also higher than the capacities reported in the literature.CONCLUSIONCombined gas stripping and adsorption could be considered an effective technique for biobutanol separation processes. © 2016 Society of Chemical Industry

Adsorptive separation and recovery of biobutanol from ABE model solutions

Adsorption is one of the most energy efficient techniques for butanol separation from dilute fermentation broths. To develop an efficient butanol adsorption process, adsorption and desorption are equally important since it is paramount to be able to desorb the adsorbed butanol to produce a high concentration butanol product. Although there are a good number of investigations done to find suitable adsorbents for this process, only few studies considered the desorption process. In this study, activated carbon F-400 was used as the butanol adsorbent since it has a high adsorption rate and capacity and is selective to butanol in the presence of other fermentation broth components. The thermal desorption process was performed in adsorption–desorption cycles both for butanol–water and acetone–butanol–ethanol (ABE) model solutions. The results for 1.5 wt% feed butanol–water binary solutions showed that the butanol adsorption capacity and the recovery of butanol were fairly constant (around 302 mg/g and 84 %, respectively) in subsequent adsorption–desorption cycles confirming that all the amount of adsorbed butanol is desorbed and the adsorption column could preserve its initial adsorption capacity in different cycles. Similar performance was obtained for butanol separation from the ABE model solution containing 1.2, 0.5, 0.2, 0.5, 0.5, 0.4 and 0.4 wt% butanol, acetone, ethanol, butyric acid, acetic acid, glucose and xylose, respectively. The adsorption capacity and recovery for butanol were 170 mg/g and 80 %, respectively.

Apparent molar properties of aqueous protic ionic liquid solutions at T = (293.15 to 328.15) K

Apparent molar volumes and apparent molar isentropic compressibilities of newly synthesized ammonium-based protic ionic liquid (PIL), namely diethylethanolammonium propionate, at T = (293.15 to 328.15) K and at atmospheric pressure were obtained from experimentally measured density and speed of sound data. Redlich-Mayer type of equation was used to calculate infinite dilution apparent molar volumes, V 2 ∞ , infinite dilution apparent molar isentropic compressibilities, K s,2 ∞ , and corresponding empirical parameters (S v, B v, S k, and B k). Positive magnitude of limiting volumetric slope S v versus m 1/2 for protic ionic liquid (PIL) + water binary solutions, suggests that PIL-water interactions are weak. Further, the temperature dependence of V 2 ∞ values has also been evaluated.

ADSORPTION OF TWEENS AND SODIUM DODECYLSULFATE FROM BINARY WATER SOLUTIONS ON THE SURFACE OF PARAFFIN

Adsorption of Tween-60, Tween-80 and from binary water solutions on the surface of paraffin was investigated. The composition of the adsorbed layers was determined from the experimental data and the parameters of the interaction of Tween’s and DDSN molecules in mixed adsorption layers using an approach Rosen. For mixed systems Twin – DDSN found a synergistic effect of their adsorption on the surface of paraffin.

Local Structures of Methanol–Water Binary Solutions Studied by Soft X-ray Absorption Spectroscopy

Liquid methanol shows one- and two-dimensional (1D/2D) hydrogen bond (HB) networks, and liquid water shows three-dimensional (3D) HB networks. We have clearly found three different local structures around the methyl group of methanol-water binary solutions (CH3OH)X(H2O)1-X at different concentrations in C K-edge soft X-ray absorption spectroscopy (XAS). With the help of molecular dynamics simulations, we have discussed the concentration dependence of the hydrophobic interaction at the methyl group in the C K-edge XAS spectra. In the methanol-rich region I (1.0 > X > 0.7), a small amount of water molecules exists separately around dominant 1D/2D HB networks of methanol clusters. In the region II (0.7 > X > 0.3), the hydrophobic interaction of the methyl group is dominant due to the increase of mixed methanol-water 3D network structures. In the water-rich region III (0.3 > X > 0.05), methanol molecules are separately embedded in dominant 3D HB networks of water. On the other hand, the pre-edge feature in the O K-edge XAS shows almost linear concentration dependence. It means the HB interaction between methanol and water is almost the same as that of water-water and of methanol-methanol.

Volumetric and acoustic studies of l-tyrosine+l-glutamic acid+water at different temperatures

Abstract The speeds of sound and densities of different concentrations of l -tyrosine + l -glutamic acid + water ternary solutions, l -tyrosine + water and l -glutamic acid + water binary solutions at T = (298.15, 308.15, 318.15) K have been measured. Using the densities and the speeds of sound, the apparent molar volumes, the apparent molar isentropic compressibilities, the limiting apparent molar volume, the limiting apparent molar compressibility, the constants ( S V , S , S V , K , S K , S and S K , E ) and the hydration number have been calculated. These parameters have been used to analyze the possible interionic interactions, such as ion–ion, solute–solvent, solvent–solvent, ion–solvent, and solute-co-solute interactions, and are discussed in terms of hydrophobic–hydrophobic, and hydrophilic–hydrophobic group interactions as well as, structure-making and structure-breaking effects in l -tyrosine + l -glutamic acid + water.

Effect of isotope substitution in binary liquids with Thermal-Lens spectroscopy

Effect of isotope substitution from the modulation of Thermal-Lens (TL) signals in binary liquid mixtures is explored using femtosecond pump–probe mode-mismatched Z-scan TL spectroscopy. Binary solutions of water and heavy water with pure methanol at various concentrations are used for the study, where pure methanol acts as the TL marker across the different samples. The TL signal is found to be effectively modulated by isotope substitution under the experimental conditions, indicating that TL signal depends on hydrogen bonding.

Calculation of the Density and Activity of Water in ATPS Systems for Separation of Biomolecules

In this study, the perturbed hard sphere chain equation of state is utilized to calculate the activity of water in binary and ternary solutions of polyethylene glycol (PEG), salt and water. The liquid density of the binary and ternary solutions is also predicted. To estimate the water activity in PEG–water binary systems, a linear correlation is obtained for the binary interaction parameter between water and PEG. Then, using this correlation and without introducing any additional binary parameters, the water activities are predicted in ternary solutions of water, salt and PEG with different molecular weights (MW). Our results show that the mean absolute average relative deviation (AARD %) of water activity for binary PEG–water solutions in 298 K is 0.73 %. In addition, the water activity in ternary solutions of water and two PEGs with different MW is predicted within 0.31 % AARD %. Furthermore, the AARD % for prediction of water activities in binary PEG–water solutions over the temperature range 308–338 K is 0.41 %. Also, the water activities of aqueous two-phase systems are predicted with AARD % = 0.64 %. In this regard, no adjustable parameters were correlated between salt and PEG. Finally, liquid densities were predicted in binary solutions of water–PEG and ternary solutions of water–PEG–salt.

AIE (AIEE) and mechanofluorochromic performances of TPE-methoxylates: effects of single molecular conformations

Two methoxy-substituted tetraphenylethylene (TPE) derivatives, tetra(4-methoxyphenyl)ethylene (TMOE) and tetra(3,4-dimethoxyphenyl)ethylene (TDMOE), were synthesized by McMurry reaction in high yields. The nearly centrosymmetric and natural propeller shape of TMOE and TDMOE excluded intermolecular effects, such as H or J-aggregation and π–π stacking, on their AIE (AIEE) and mechanofluorochromic performance. The crystal structures of TMOE and TDMOE, and theoretical calculations proved that their emission colours are determined by single molecular conjugation. These molecules were used to investigate pure conformational effects on molecular emissions. The spectral properties of these molecules in five environments of crystal(s), THF solution, THF–water binary solution, solidified THF and amorphous states, were investigated. The crystalline to amorphous phase transition by grinding resulted in good mechanofluorochromic performances with high quantum yields and distinguishable emission change, which was further explored as anti-counterfeiting inks on banknotes.

Electron Density Dependent Composition of the Solvation Shell of Phenol Derivatives in Binary Solutions of Water and Ethanol

The dynamic motions of solvent molecules in the solvation shell of phenols in binary water–ethanol solutions have been examined experimentally by measuring the solvent relaxation times using phase-fluorometry. The results show that the mono-exponential character of the solvent relaxation changes to bi-exponential just after the ethanol content of the bulk solution exceeds a critical value. This value depends on the electron density of the aromatic rings of the phenolic molecules. Above the critical values much higher ethanol content is observed in the solvation shell compared to the bulk solutions. This observation is applicable in wide scale of chemical processes in condensed phase and indicates that further research is needed towards development of a picture at the atomic scale.

Synthesis of GaN microspheres and their properties

Abstract In this article, we report the fabrication of GaN microspheres from Ga2O3 microspheres. Gallium chloride in ethanolamine–water binary solution at 180 °C for 12 h results in γ-Ga2O3 microspheres, which was further converted into wurtzite GaN microspheres by calcinations in the flow of NH3 gas at 800 °C for 1.5 h. The synthesized Ga2O3 and GaN microspheres were characterized using XRD, FESEM, and HRTEM. The XRD patterns indicated that well-crystallized γ-Ga2O3 and wurtzite GaN were formed in a solvothermal and calcination process, respectively. The FESEM images indicated the formation of well-organized Ga2O3 and GaN microspheres, which were composed of nanosheets and nanoparticles, respectively. The FESEM observations also suggest that the initial Ga2O3 structural motifs were unaffected by the subsequent high temperature chemical transformations process. Raman spectroscopy, PL spectrum and TGA–DTA test of the as-prepared GaN product have been performed. The results indicate that GaN microspheres prepared in our experiment have excellent optical properties and thermal stability.

Thermosolvatochromism of Nitrospiropyran and Merocyanine Free and Bound to Cyclodextrin

The thermosolvatochromism of nitrospiropyran free and bound to cyclodextrin was studied in dimethylsulfoxide (DMSO)-water binary solvent systems. Spiropyran was interconverted to merocyanine by heating the sample to 55 °C. The merocyanine (MC) was converted back to spiropyran (SP) either by cooling the sample to room temperature or irradiating the sample with a visible light emitting diode. Steady state absorption spectra of SP and MC samples in the free state and bound to cyclodextrin were obtained in several DMSO-water binary solutions. Emission spectra of MC both free and cyclodextrin-bound were also acquired. Blue-shifted absorption and emission spectra of the studied molecules with increasing solvent polarity suggest that the dipole moments of free and bound merocyanines are higher in the ground state compared to the excited state. Merocyanine dipole moments in the ground and excited states were determined using thermosolvatochromism measurements and the Lippert-Mataga, Bakhshiev, and Kawski-Chamma-Viallet polarity functions. A large change in the dipole moment (ca. 16 D) of the merocyanine in aqueous DMSO was obtained upon electronic excitation, S(1) ← S(0). Analysis of the merocyanine Stokes' shifts as a function of solvent polarity indicates that both general solvent effects and specific solvent effects are present in all systems studied. These findings reveal that merocyanine could be utilized as a polarity sensor for DMSO-water binary solutions.

Volumetric Characterization of Interactions of Protein Groups with Glycine Betaine

We report the volumetric properties of N-acetyl amino acid amides with unionizable side chains and oligoglycines in binary solutions of water and glycine betaine, a protective cosolvent. We analyze these data within the framework of a statistical thermodynamic formalism to determine the association constants for the reaction in which glycine betaine binds to the peptide backbone and amino acid side chains replacing four water molecules. The association constants are linked to the free energy of transfer of functional groups from water to a glycine betaine solution, Gtr. Transfer free energy, Gtr is the sum of a change in the free energy of cavity formation, GC, and the differential free energy of solute-solvent interactions, GI, in a concentrated glycine betaine solution and water. We compare our results with similar data on volumetric measurements in water-urea binary mixtures. We find little differences in GI for protein functional groups in urea and glycine betaine solutions. Comparative analysis reveals that solute-cosolvent interactions are favorable for the glycyl unit and the majority of amino acid side chains in both glycine betaine and urea solutions. These results are consistent with the picture in which the free energy of cavity formation, GC, is the decisive factor determining the differential stabilizing/destabilizing action of urea and glycine betaine.

Quantitative analysis of alcohol–water binary solutions using Raman spectroscopy

Raman spectroscopy was used for rapid and in situ measurements of alcohols in alcohol–water binary systems. An external standard was used to eliminate factors such as laser power or instrumental effects. Band ratios between the Raman bands of the target molecule and that of acetonitrile as external standard were calculated and found to be proportional to the mass fraction of alcohol. Better linearity was achieved as compared with that in the calibration curve obtained by plotting the Raman intensity alone. The equations of the calibration curves were y=0.2747 x with R 2 of 0.9996 and y=0.2189 x+1.340×10 −3 with an R 2 of 1.000 in methanol–water and in ethanol–water binary systems, with y and x denoting the Raman intensity ratio and the mass fraction of alcohol, respectively.

Synthesis of InP hierarchical microspheres and its optical property

InP hierarchical microspheres with an average diameter of 1 μm self-assembled from nanodollops of about 200 nm were synthesized by the reaction of 2 mmol of InCl 3 and 15 mmol of yellow phosphorus in ethanolamine–water binary solution at 170 °C for 12 h. Experiments show that the morphologies of the products were mainly affected by the reaction temperature and the quantities of reactants. The InP hierarchical microspheres prepared in our experiment could emit blue light, which probably correlates to the crystal defects.

Preferential solvation of lysozyme by dimethyl sulfoxide in binary solutions of water and dimethyl sulfoxide

To reveal the denaturation mechanism of lysozyme by dimethyl sulfoxide (DMSO), thermal stability of lysozyme and its preferential solvation by DMSO in binary solutions of water and DMSO was studied by differential scanning calorimetry (DSC) and using densities of ternary solutions of water (1), DMSO (2) and lysozyme (3) at 298.15 K. A significant endothermic peak was observed in binary solutions of water and DMSO except for a solution with a mole fraction of DMSO (x2) of 0.4. As x2 was increased, the thermal denaturation temperature Tm decreased, but significant increases in changes in enthalpy and heat capacity for denaturation, ΔHcal and ΔCp, were observed at low x2 before decreasing. The obtained amount of preferential solvation of lysozyme by DMSO (∂g2/∂g3) was about 0.09 g g−1 at low x2, indicating that DMSO molecules preferentially solvate lysozyme at low x2. In solutions with high x2, the amount of preferential solvation (∂g2/∂g3) decreased to negative values when lysozyme was denatured. These results indicated that DMSO molecules do not interact directly with lysozyme as denaturants such as guanidine hydrochloride and urea do. The DMSO molecules interact indirectly with lysozyme leading to denaturation, probably due to a strong interaction between water and DMSO molecules.

Thermodynamics of Lysozyme in Binary Solutions of Water + DMSO

Thermodynamics of Lysozyme in Binary Solutions of Water + DMSO

Synthesis of In/InP core–shell nanospheres and their transformation into InP hollow nanospheres

Polycrystalline InP hollow nanospheres with an average size of 520 nm and shell thickness of about 110 nm were obtained by acid treatment of In/InP core–shell nanospheres which were solvothermally synthesized in ethanolamine–water binary solution at 180 °C. The sizes of InP hollow nanospheres increased with the increasing reactants quantities. Meanwhile the shell thicknesses of InP hollow nanospheres could be controlled by varying the quantity of yellow phosphorus. The process of In/InP core–shell nanospheres transforming into InP hollow nanospheres was also investigated. The InP products prepared in our experiments can emit blue light, which is different from previous reports and increases the potential application of InP nanomaterial.

Thermodynamic behavior of complexation of 18-crown-6 with Tl+, Pb2+, Hg2+, and Zn2+ metal cations in methanol-water binary media

The equilibrium constants and thermodynamic parameters for complex formation of 18-Crown-6 (18C6) with Tl+, Pb2+, Hg2+, and Zn2+ metal cations have been determined by conductivity measurements in methanol (MeOH)-water (H2O) binary solutions. 18-Crown-6 forms 1:1 complexes with Hg2+ and Zn2+ cations, but in the case of Tl+ and Pb2+ cations, in addition to 1:1 stoichiometry, 1:2 (ML2) complexes are formed in some binary solvents. The thermodynamic parameters (ΔHc0 and ΔSc0), which were obtained from the temperature dependences of equilibrium constants, show that in most cases the complexes are enthalpy destabilized but entropy stabilized. Non-linear behavior is observed between the equilibrium constants (log Kf) of complexes and the composition of the mixed solvent. The selectivity of the ligand for these metal cations is sensitive to the solvent composition, and, in some cases, the selectivity order is reversed in certain compositions of the mixed solvent. The results also show that the mechanism of complexation reactions and the stoichiometry of complexes of some metal cations change with the nature and even with the composition of the mixed solvent.