Analysis of the application of optical two-wavelength techniques to measurement of the Soret coefficients in ternary mixtures

We discuss the application of two-wavelength optical methods for the determination of Soret coefficient in ternary mixtures. Though the principle of such an approach was formulated in the literature earlier, we have found a significant obstacle to its implementation and suggested a way to circumvent that obstacle. The main target of our approach is the analysis of the compatibility of the matrices of contrast factors (the derivatives of refractive indices with respect to concentrations) with available light sources used for measuring the Soret effect in ternary mixtures. We report on the development of a simple mathematical approach to verify the applicability of the chosen wavelengths for laser diodes to measure transport coefficients for a certain class of ternary mixtures. The approach has been applied to a number of aqueous ternary mixtures: water–ethanol–k-ethyleneglycol, k?=?mono, di, tri, and water–t-butanol–DMSO) and light sources in the visible λ₁?=?670?nm and infrared λ₂?=?925?nm spectrum. The regions of feasibility/infeasibility of the methods have been revealed for these mixtures.     

Self-Indicating Surfactants: Potentially Micellar Solvatochromic Iron(II) Complexes

The preparation of ternary iron(II) complexes [Fe(CN)₂(LL)₂] and [Fe(CN)₄(LL)]^2-, where LL = a Schiff base derived from 2-acetyl pyridine and a long chain amine 1-Me(CH₂)_nNH₂ (n = 11, 15, 17), is described. These complexes exhibit strong solvatochromism and can thus be used to probe solvation in organised aqueous media, as in ternary water - Aerosol OT- hexanol mixtures. They also have a dramatic effect on the micellisation behaviour of the uncharged surfactant Triton X-100.     

Dielectric relaxation study of ascorbic acid solutions in pure dimethylsulfoxide (or diethylsulfoxide) and in dimethylsulfoxide (or diethylsulfoxide)/water mixtures

The complex dielectric spectra of ascorbic acid solutions in pure dimethylsulfoxide (or diethylsulfoxide) and in dimethylsulfoxide (or diethylsulfoxide)/water mixtures have been measured at frequencies between 100 MHz and 20 GHz at 298.15 K.Two kinds of dielectric relaxation processes were observed in each solution. The low frequency relaxation (Debye term) is assigned to solute. The high frequency relaxation (Cole-Davidson term) is ascribed to practically unaffected solvent.From the results obtained it follows that relaxation time and relaxation strength in DESO containing solutions (i.e. binary AA/DESO and ternary AA/DESO/water systems) are greater than those in DMSO containing solutions.     

Ultrasonic and IR study of intermolecular association through hydrogen bonding in ternary liquid mixtures

Complex formation in ternary liquid mixtures of dimethylsulfoxide (DMSO) with phenol and o-cresol in carbontetrachloride has been studied by measuring ultrasonic velocity at 2 MHz, in the concentration range of 0.019-0.162 (in mole fraction of DMSO) at varying temperatures of 20, 30 and 40 degrees C. Using measured values of ultrasonic velocity, other parameters such as adiabatic compressibility, intermolecular free length, molar sound velocity, molar compressibility, specific acoustic impedance and molar volume have been evaluated. These parameters have been utilized to study the solute-solute interactions in these systems. The ultrasonic velocity shows a maxima and adiabatic compressibility a corresponding minima as a function of concentration for these mixtures. The results indicate the occurrence of complex formation between unlike molecules through intermolecular hydrogen bonding between oxygen atom of DMSO molecule and hydrogen atom of phenol and o-cresol molecules. The excess values of adiabatic compressibility and intermolecular free length have also been evaluated. The variation of both these parameters with concentration also indicates the possibility of the complex formation in these systems. Further, to investigate the presence of O-HO bond complexes and the strength of molecular association with concentrations, the infrared spectra of both the systems, DMSO-phenol and DMSO-o-cresol, have been recorded for various concentrations at room temperature (20 degrees C). The results obtained using infrared spectroscopy for both the systems also support the occurrence of complex formation through intermolecular hydrogen bonding in these ternary liquid mixtures.     

Analysis of methanol extraction from aqueous solution by n-hexane: Equilibrium diagrams as a function of temperature

This paper contains the results of a new experimental study of liquid–liquid equilibrium (LLE) as a function of temperature for the ternary mixture n-hexane + methanol + water under atmospheric conditions. The computed coexistence curves were very asymmetrical with respect to n-alkane + water composition at low operation temperature. A comparative analysis was performed by application of group contribution methods to predict the experimental equilibria behaviour of this ternary mixture. The experimental tie lines data were correlated to test consistency with the Othmer–Tobias equation. The obtained results point out the strong interaction by hydrogen bonds forming the so-called iceberg clusters of hydroxylated molecules at low concentration of n-hexane, a slight influence of temperature being observed. As a result of this intense interaction, sharp separations of n-hexane + methanol mixtures by extraction are possible at low temperature and small quantities of solvent. Extraction process simulation confirms n-hexane as an adequate medium for diluted methanol concentration.     

Effect of ultrasound on the solvolysis of 2-chloro-2-methylpropane in aqueous alcoholic solvents

Ultrasonic irradiation was found to acclerate the solvolysis of 2-chloro-2-methylpropane in aqueous ethanol mixtures. The effects were more marked at lower temperatures and higher alcohol compositions, with a 20-fold rate acceleration occurring at 10°C and 60 wt%. The kinetic data were analysed with reference to the variation in solvent structure and vapour pressure. Enthalpies and heat capacities of activation in both the presence and absence of ultrasound were also determined. The result spresented in this Paper confirm the existence of a region of maximum structure in the binary mixture.     

磷酸根与磷酸基水化作用之比较—红外光谱研究

本文运用傅立叶变换红外光谱，对水／ＮａＤＥＨＰ／正庚烷反胶束体系中的磷酸根及磷酸三丁酯－水体系中磷酸基的水化作用进行了研究。     

近红外光谱研究水与甲醇混合溶液的氢键作用

对于浓度为0～100wt％(浓度间隔为5wt％)的水-甲醇混合溶液的近红外光谱,通过分析OH组合谱带和倍频谱带随浓度的变化,探索了水-醇溶液中的氢键作用。由于OH谱带在近红外区域重叠比较严重,采用了不同的光谱分析方法——二阶导数、主成分分析和二维相关分析来提高光谱分辨率,进而达到从水-甲醇溶液的近红外光谱获取有用信息的目的。定性地阐述了水-醇混合溶液中的水和醇之间通过氢键的可能结合方式,为探索水-醇混合溶液中的氢键作用提供了一种新的可能性。     

Study of ion–solvent interactions and activation energy of LiBr in DMSO,H<Subscript>2</Subscript>O and DMSO–H<Subscript>2</Subscript>O mixtures at various temperatures

The Jones–Dole B coefficients of the electrolyte Lithium bromide (LiBr), reference salts tetra butyl ammonium tetra phenyl borate (BU₄NBPh₄), tetra butyl ammonium bromide (BU₄NBr), and potassium chloride (KCl) in dimethylsulfoxide (DMSO), water, and DMSO–water mixtures were obtained at different temperatures range from 25 to 45 °C For this, the relative viscosities were measured for Lithium bromide (LiBr) and reference salts in DMSO, water, and DMSO–water mixtures at above-mentioned temperatures. The B coefficients of these electrolytes were behaved as structure makers in DMSO, while in H₂O and DMSO–H₂O mixtures, the B-coefficient values were less positive showing the weak structure-making effect. Ionic viscosity B coefficients allow us to assess the behavior of ions in the solvent mixtures. In this study it was observed that all the values of ionic B coefficient of (Li⁺) were positive and small showing the weak structure-making effects. It was also observed that Br⁻ ions maintain negative B coefficient values in all DMSO–H₂O mixtures, except in 60% DMSO mole fraction. From this it can be concluded that Br⁻ ion behaved as a structure breaker in water and in all DMSO–H₂O mixtures except in 60% DMSO mole fraction mixtures. The low B _± values of alkali metal ions and Br⁻ ions in water are due to the breakdown of the tetrahedral structural of water and the formation of strongly structured solvated ion. It is also observed that the values of the energy of activation of the flow for LiBr are greater in DMSO–water mixtures and in pure water than in DMSO. This may be due the presence of a network of hydrogen bonds which cause the hindrance in the flow of the solution of LiBr in DMSO–water mixtures and in pure water than in DMSO.     

Quantitative and multicomponent analysis of prevalent urinary calculi using Raman spectroscopy

This study established a quantitative micro‐Raman spectroscopic (MRS) method for measuring multicomponents (binary and ternary compositions) of prevalent urine calculi extracted from the ureter after the ureteroscopic lithotripsy (URSL) procedure. The analysis used calibration curves of known mixtures of synthetically prepared calcium oxalate monohydrate (COM), hydroxyapatite (HAP), calcium oxalate dehydrate (COD), dicalcium phosphate dehydrate (DCPD), and uric acid. A variety of samples of binary and ternary mixtures including COM/HAP, COM/COD, COD/HAP, COM/uric acid, COD/uric acid, HAP/uric acid, HAP/DCPD, and COM/COD/HAP were prepared in various concentration ratios for use as the basis of the quantitative analysis. Intensities of the characteristic bands at 961 cm⁻¹ (I_HAP), 986 cm⁻¹ (I_DCPD), 1402 cm⁻¹ (I_UricAcid), 1462 cm⁻¹ (I_COM), and 1477 cm⁻¹ (I_COD) were used for the calculation. We derived a set of quantitative analysis equations for the ternary composition COD/COM/HAP group by combining two binary equations from the groups COM/COD and the HAP/COM. This study quantitatively measured 18 urine samples extracted from the 18 patients' ureters after the URSL procedure. Fifteen samples were binary mixtures, whereas three samples were ternary mixtures. This research successfully applied the quantitative MRS‐based analysis technique from bench to bedside. Copyright © 2012 John Wiley & Sons, Ltd.     

胆酸-磷酸-钙三元络合物的红外光谱表征及结构特性

本文详细地研究了胆酸－磷酸－钙三元络合物的结构特性,得一些很有价值的结果。     

Molecular dynamics study on water self-diffusion in aqueous mixtures of methanol,ethylene glycol and glycerol: investigations from the point of view of hydrogen bonding

Molecular dynamics simulations have been performed to investigate the aqueous binary mixtures of alcohols, including methanol, ethylene glycol (EG) and glycerol of molalities ranging from 1 to 5 m at the temperatures of 273, 288 and 298 K, respectively. The primary purpose of this paper is to investigate the mechanism of water self-diffusion in water-alcohol mixtures from the point of view of hydrogen bonding. The effects of temperature and concentration on water self-diffusion coefficient are evaluated quantitatively in this work. Temperature and concentration to some extent affect the hydrogen bonding statistics and dynamics of the binary mixtures. It is shown that the self-diffusion coefficient of water molecules decreases as the concentration increases or the temperature decreases. Moreover, calculations of mean square displacements of water molecules initially with different number n of H-bonds indicate that the water self-diffusion coefficient decreases as n increases. We also studied the aggregation of alcohol molecules by the hydrophobic alkyl groups. The largest cluster size of the alkyl groups clearly increases as the concentration increases, implying the emergence of a closely connected network of water and alcohols. The clusters of water and alcohol that interacted could block the movement of water molecules in binary mixtures. These findings provide insight into the mechanisms of water self-diffusion in aqueous binary mixtures of methanol, EG and glycerol.     

The wettability of poly(tetrafluoroethylene) by aqueous solutions of ternary surfactant mixtures

Contact angle measurements on poly(tetrafluoroethylene) (PTFE) surface were carried out for the systems containing ternary mixtures of cetyltrimethylammonium bromide (CTAB) and p-(1,1,3,3-tetramethylbutyl)phenoxypoly(ethylene glycols), Triton X-100 (TX100) and Triton X-165 (TX165). The aqueous solution of ternary surfactant mixtures were prepared by adding the third surfactant to the binary mixture of the surfactants where the synergetic effect in the reduction of the surface tension of water was determined, to compare the influence of the third surfactants on the values of surface tension of this binary mixture and the values of the contact angle on PTFE. The obtained results and calculations indicate that the ternary mixtures of CTAB + TX165 (αCTAB = 0.2, γ_LV = 60 and 50 mN/m) + TX100 (C = 10⁻⁸ to 10⁻² M) have the biggest efficiency of the reduction of contact angle of water on PTFE in comparison to aqueous solutions of the single surfactants and their binary and ternary mixtures. Also in the case of all studied ternary mixtures of surfactants at concentrations of the bulk phase corresponding to unsaturated monolayer at water-air interface the adsorption of surfactants at PTFE-water interface is different than that at water-air interface, but is the same at concentrations near the critical micelle concentration (CMC). Thus the linear dependences between γ_LV cos θ − γ_LV and cos θ − 1/γ_LV, in the range of concentration studied for all systems confirm the same adsorption at two interfaces only at C near the CMC.     

Hydrogen‐bonded nucleophile effects in ANS: the reactions of 1‐chloro and 1‐fluoro‐2,4‐dinitrobenzene with 2‐guanidinobenzimidazole, 1‐(2‐aminoethyl)piperidine and N‐(3‐aminopropyl)morpholine in aprotic solvents

The kinetics of the reactions of 2,4‐dinitrofluorobenzene (DNFB) and 2,4‐dinitrochlorobenzene (DNClB) with 2‐guanidinobenzimidazole (2‐GB) at 40 ± 0.2 °C in dimethylsulphoxide (DMSO), toluene, and in toluene–DMSO mixtures, and with 1‐(2‐aminoethyl)piperidine (2‐AEPip) and N‐(3‐aminopropyl)morpholine (3‐APMo) in toluene at 25 ± 0.2 °C were studied under pseudo first‐order conditions. For the reactions of 2‐GB carried out in pure DMSO, the second‐order rate coefficients were independent of the amine concentration. In contrast, the reactions of 2‐GB with DNFB in toluene, showed a kinetic behaviour consistent with a base‐catalysed decomposition of the zwitterionic intermediate. These results suggest an intramolecular H‐bonding of 2‐GB in toluene, which is not present in DMSO. To confirm this interpretation the reactions were studied in DMSO–toluene mixtures. Small amounts of DMSO produce significant increase in rate that is not expected on the basis of the classical effect of a dipolar aprotic medium; the effect is consistent with the formation of a nucleophile/co‐solvent mixed aggregate. For the reactions of 3‐APMo with both substrates in toluene, the second‐order rate coefficients, k_A, show a linear dependence on the [amine]. 3‐APMo is able to form a six‐membered ring by an intramolecular H‐bond which prevents the formation of self‐aggregates. In contrast, a third order was observed in the reactions with 2‐AEPip: these results can be interpreted as a H‐bonded homo‐aggregate of the amine acting as a better nucleophile than the monomer. Most of these results can be well explained within the frame of the ‘dimer nucleophile’ mechanism. Copyright © 2010 John Wiley & Sons, Ltd.     

荧光俘获效应对掺饵氧化物玻璃光谱性质的影响

测试了不同掺杂浓度和样品厚度下掺铒磷酸盐和碲酸盐玻璃的吸收光谱、荧光光谱和荧光寿 命，计算了Er³⁺离子在1.53 μm处的吸收截面(σ_a)、发射截面(σ _e)、自发辐射跃迁概率(A_rad)、辐射跃迁寿命(τ_rad) 、以及辐射跃迁量子效率(η)等光谱参数.讨论了荧光俘获效应对掺铒磷酸盐和碲酸盐玻璃 光谱性质及光谱参数的影响.结果表明即使在铒离子低掺杂浓度(0.1 mol% Er₂O ₃)下，荧光俘获效应也普遍存在于掺铒玻璃材料中，使得荧光寿命(τ_{f)和荧光半高宽(FWHM)随样品的厚度和铒离子掺杂浓度增加而增大，导致碲酸盐和磷酸 盐玻璃中τf分别增加11%—37％和6%—17%，FWHM分别增加15%—64%和11%—55% ，使得掺铒玻璃材料的放大品性参数(σe×FWHM) 也相应被估高.由于铒离子在 碲酸盐玻璃中在1.53 μm处吸收和发射截面重叠面积较大，加之铒离子在前者基质中的发射 截面高于后者，使得掺铒碲酸盐玻璃中的荧光俘获效应高于磷酸盐玻璃. 关键词： 荧光俘获 铒离子 碲酸盐玻璃 磷酸盐玻璃}     

Vibrational studies of polar aprotic molecule in aromatic chemical and isotropic solvents: experimental and quantum chemical investigations

Raman spectroscopic technique has been used to study the intermolecular interactions and dynamics of SO, C―H and CSC stretching modes of dimethyl sulfoxide (DMSO) in binary mixtures using methyl benzene (MBN) and deuterated methyl benzene (MBNd) aromatic solvents. The Raman band of SO stretching mode has been deconvoluted into four distinct bands for neat DMSO as well as in binary mixtures. Deconvoluted bands in neat DMSO were assigned as monomer, cyclic out‐of‐phase, cyclic in‐phase and chain dimers having peak wavenumbers 1069.10, 1056.60, 1041.50 and 1027.30 cm⁻¹ respectively. Peak wavenumber of SO stretching mode shows red shift, while peak wavenumbers of C―H and CSC stretching modes show blue shift with the increase in solvent concentration. The vibrational relaxation phenomena for all the stretching modes have been studied as a function of solvent concentration. Quantum‐chemical calculations have been carried out to gain more insight into the self‐association of DMSO and in interacting environment with the solvents using ab initio and density functional theory method. The ab initio basis set is HF/6‐31 + G (d, p) for the interacting system. The hydrogen bond complexes of DMSO with MBN and MBNd using IEF‐PCM model have been calculated using B3LYP functional and 6‐31 + G(d,p) basis sets. Theoretical calculations have been compared with the experimental findings and we obtained good coherence of the results. Copyright © 2015 John Wiley & Sons, Ltd.     

Laser Raman spectroscopy of the effect of solvent on the low-frequency oscillations of organic molecules

The effect of solvent on low-frequency oscillations is studied using an example of the 1,1,2,2-tetrachloroethane (TCE) and 1,1,2,2-tetrabromoethane (TBE) molecules, which exhibit torsional oscillations in the terahertz range. Dimethylsulfoxide (DMSO) and carbon tetrachloride (CTC) are used as solvents. It is demonstrated that a decrease in the concentration of the substance under study in the TBE/CTC, TCE/DMSO, and TCE/CTC mixtures leads to a frequency shift of the low-frequency oscillation. The shift is not observed in the TBE/DMSO mixture but a decrease in the TBE concentration causes significant broadening of the low-frequency line.     

Study of various parameters influencing the fixation of metallic ions Cu2+, Zn2+, and Ni2+ at the catalytic Amberlyst-15 resin in the presence of alcohols

The ionic exchange behavior of Zn²⁺, Ni²⁺, and Cu²⁺ metallic ions on Amberlyst-15 commercial resin was studied as a function of resin solution contact time, initial concentration of metallic ions, nature of the solvent, and the amount of resin. The metallic ions were studied in ternary mixtures using both column and batch experiments. In addition, water, methanol, ethanol, and propan-2-ol were used as solvents for dissolving metallic ions. It was found that the resin behavior depends on the solvent nature and the metallic ion concentration. The analysis of solutions by atomic absorption spectrometry revealed that the affinity of the resin for the studied metallic ions followed the sequence Cu²⁺ > Ni²⁺ > Zn²⁺ in the case of an aqueous medium. Furthermore, uptake increased with increasing amount of resin. A better uptake was observed in the case of the 75:25 % water/methanol compositions when the column technique was used. For the batch technique, we noted a better uptake using 100 % water. The uptake rate decreased with an increase in the number of carbons for the 50 % water–50 % alcohol solvents. The acid–base properties of Amberlyst-15 commercial resin were studied by 2-propanol decomposition test. Propene and acetone are the main expected products and it is believed that they are formed through dehydration or dehydrogenation reaction on acid and base sites, respectively.     

Synthesis and Spectral Properties of Novel Fluorescent Poly(oxyethylene Phosphate) Tris(β-diketonate) Europium (III) Complexes

Novel poly(oxyethylene phosphate) tris(β-diketonate) europium (III) complexes have been synthesized by an improved procedure using the Atherton–Todd reaction conditions. N-ethyldiisopropylamine has been used as a mild base and propylene oxide as an acid scavenger in order to obtain poly(oxyethylene phosphate) in yield and purity higher than those achieved by conventional methods. The compounds have been characterized by ¹H, ¹³C, and ³¹P NMR and FTIR techniques. Their absorption, fluorescent excitation and emission spectra of chloroform and abs. ethanol solutions have been recorded and studied. The luminescent quantum yields and decay times have been determined and a dependence on the length of the oxyethylene spacer between phosphate groups has been established. The new polymer complexes are water soluble and have increased luminescence decay time in comparison with corresponding ternary complexes.