Standard Gibbs energies of transfer of potassium tetraphenylborate from water to straight-chain n-alkanols

Solubilities of potassium tetraphenylborate in water, methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, 1-hexanol, and 1-octanol at 15, 25, 35, 45, 55°C have been determined by spectrophotometry. The standard Gibbs energy of transfer of potassium tetraphenylborate form water to straightchain n-alkanols and the medium effect of potassium tetraphenylborate from 15 to 55°C have been calculated. Furthermore, the contribution of microscopic interactions to the standard Gibbs energy of transfer of potassium tetraphenylborate is calculated and discussed.     

四苯硼钾从水到二甲基亚砜混合溶剂⒇中的标准迁移自由能和介质效应

二甲基亚砜（ＤＭＳＯ）是一种特殊的有机溶剂，它不但是良好的萃取剂、增塑剂和有机化学反应的中间体，而且由于它含有ＳＯ基团，可以作为良好的质子接受体，与Ｌｅｗｉｓ酸形成氢键缔合物，致使一些含ＤＭＳＯ的混合溶剂表现出很多的反常特性。因此，ＤＭＳＯ在溶液化学...     

Thermodynamic Properties of Transfer for Tetraphenylarsonium Tetraphylborate from Water to n—Alkanols

Solubilities of tetraphenylarsonium tetraphenylborate(Ph4AsB-Ph4) in water,methanol,ethanol, 1-propanol,1-butanol,1-pentanol,1-hexanol and 1-octanol at T=293.2,298.2,303.2 and 308.2 K have been determined by spectrophotometry,The standard transfer Gibbs energy (△trG^0w→s) and entropy (△trS^0w→s) of Ph4AsBPh4 from water to the n-alkanols at temerature from 293.2 K to 308.2 K have been obtained.Fur-thermore,the contribution of microscopic interaction to the standard Gibbs energy of transfer for Ph4AsBPh4 was calculated and discussed,The results show that the effect of hydrophobic inderaction of Ph4AsBPh4 on its transfer process is the most im-portant factor .According to the thermodynamical principle,the transfer process of Ph4AsBPh4 from water to the n-alkanols is the entropy dominanted.     

KBPh4由水到系列水-醇混合溶剂的迁移自由能

由于四苯硼盐在分析化学、生物学、电化学等各领域中的广泛用途及其大阴离子在研究与计算单个离子迁移热力学函数中所具有的特殊作用,人们对四苯硼盐的溶液热力学性质进行了广泛研究,特别是对四苯硼钠和可作为参考电解质的四苯硼盐进行了深入细致的研究 [1, 2],得到了一些重要的的结论,为溶液理论的研究提供了有力的实验基础 .但是文献中对难溶碱金属四苯硼盐由单一到不同混合溶剂中的迁移热力学性质的系统研究较少 .在前文 [3]对 KBPh4由水到水-异丙醇和由甲醇到甲醇-异丙醇混合溶剂的迁移自由能进行研究的基础上,我们系统地对 KB…     

四苯硼酸铷由水至直链一元醇中的标准迁移热力学函数

在288.15～328.15K下,用光度法测定RbBPh~4在直链一元醇中的溶解度,计算并讨论RbBPh~4由水至直链一元醇中的标准迁移热力学函数,经微机曲线拟合给出Δ~t~rG^°~w~→~s,Δ~t~rS^°~w~→~s随温度及碳原子数的经验关系。用Born模型及单层结构模型对标准迁移自由能变化规律进行定性与定量的解释。     

四苯硼钠水溶液的系列热力学性质

在288.15～318.15K范围内,用等压法测定了四苯硼钠在不同浓度水溶液中的平均活度系数和渗透系数,计算了不同浓度时的超额自由能、相对偏摩尔焓、偏摩尔热容。经计算机曲线拟合给出热力学性质的经验计算公式。     

四苯硼钠在活性炭表面吸附过程的疏水相互作用

In this paper, the adsorption characteristics of sodium tetraphenylborate(NaBPh4) on activated carbon at 298.2,303.2,308.2,313..2 and 323.2 K was studied.The results show that the adsorption isotherm of NaBPh4 on activated carbon at different temperatures could be described using Langrnuir equation. Furthermore, the standard Gibbs energy, enthalpy, entropy and hydrophobic interaction Gibbs energy for the adsorption of NaBPh4 on activated carbon were studied, and the result shows that the hydrophobic interaction of BPh4^- ion plays the most important role for the transfer of NaBPh4 from water to activated carbon surface.     

四苯硼钾由单-到不同混合溶剂的迁移自由能

KBPh4作为一种典型的大阴离子电解质 ,在研究与计算大分子电解质的迁移热力学性质中起着重要的作用 .讨论大分子电解质与不同溶剂间的作用 ,还可以为萃取、色谱及表面活性剂的研究提供理论依据 .一些文献及我们前文曾对四苯硼盐由水到一些纯溶剂 [1,2]及从水到某些水-有机混合溶剂中的标准迁移自由能进行了研究 [3],但对四苯硼盐在有机-有机混合溶剂中的研究报导极少 .本文对 KBPh4由水到水-异丙醇和由甲醇到甲醇-异丙醇混合溶剂的标准迁移自由能进行了研究和探讨 .1实验部分 1.1实验仪器及方法 　　用 CS501型超级恒温槽恒温 ;用 WF…     

The solvation of fluoride ions. I. Free energies for transfer from water to aqueous alcohol and acetonitrile mixtures

The solubilities of NaF and LiF have been measured in mixtures of water with methanol, ethanol, ethylene glycol and acetonitrile over the whole composition range. Gibbs free energies of transfer of the fluoride ion from water to the mixed and pure solvents have been calculated from the solubility data via the tetraphenylarsonium tetraphenylborate assumption. The values so obtained indicate that the fluoride ion is preferentially solvated by water as a result of its strong hydrogen-bonding capabilities. Desolvation of the fluoride ion is especially marked in acetonitrile-rich solutions.     

四苯硼铵从H2O到H2O-TBA的ΔGΘt和介质效应

Solubilities of ammonium tetraphenylborate (NH4BPh4) in water-t-butyl alcohol (TBA) mixed solvents at 283.15,293.15,298.15,303.15 and 308.15K have been determined by spectrophotometry.The standard Gibbs energy of transfer (ΔGΘt) of NH4BPh4 from water to H2)-TBA mixtures and the primary medium effect of NH4BPh4 from 283.15 to 308.15K were studied.The results show that-ΔGΘt exhibits a complicated variation pattern with the increase in the mole fraction of TBA [x(TBA)] at the same temperature.When x(TBA)<0.06,-ΔGΘt increases very slowly with x(TBA),the-ΔGΘt increases rapidly with x(TBA) when x(TBA) from 0.06 to 0.2.For x(TBA)>0.2,the -ΔGΘtdecreases with increasing x(TBA).The largest value of -ΔGΘt occurs at x(TBA)=0.2.The main reason for this variation was analyzed and discussen.     

Thermodynamics of glycine solution in aqueous urea. Rule \sqrt m

The solution heats of glycine in aqueous urea have been determined by calorimetry at 298 K (molality 0–13) and 313 K (molality 0–22). The solution heat of the amino acid is described by the linear dependence of this quantity on the square root of the urea molality. The enthalpy, entropy, and Gibbs energy of the transfer of glycine from water to aqueous urea, as well as the heat capacity, entropy variation, and Gibbs energy of glycine solution have been calculated for the temperature range 273–323 K. It is found that urea additions to water reverse the sign of the heat capacity of solution.     

Adsorption and Aggregation Properties of Some Polysorbates at Different Temperatures

Measurements of the surface tension of aqueous solutions of polysorbates (Tween 20, Tween 60 and Tween 80) at 293, 303 and 313 K were made. On the basis of the obtained results the Gibbs surface excess concentration of the Tweens at the water–air interface and critical micelle concentrations were determined. Knowing the Gibbs surface excess concentration and taking into account the difference between the limiting area occupied by water and Tween molecules at the water–air interface, the fraction occupied by Tween molecules was established. The limiting area occupied by the Tween molecule was calculated by applying the Joos equation. The area determined in such a way was confirmed by the calculations of cross section of Tween molecules based on the bond lengths and the angles between them as well as the average distance between the molecules, taking into account their different conformations. This area was used for calculation of the standard Gibbs energy of adsorption using the Langmuir equation. The standard Gibbs energy of Tweens adsorption at the water–air interface was also calculated from the hydrophobic part of Tween molecule–water interface tension and that of hydrophobic part. Using the determined values of standard Gibbs energy of adsorption at different temperatures, the standard enthalpy and entropy values were deduced. The standard thermodynamic functions of micellization were also determined and compared to the Gibbs energy of Tween molecules interactions through the water phase.     

四苯硼铵从H2O到H2O-TBA的ΔG()t和介质效应

电解质在水和含水混合溶剂间的迁移热力学性质,对于研究解析电解质与溶剂间的相互作用及其变化规律有着重要的作用.因此,长期以来一直受到人们的重视.碱金属及类碱金属四苯硼盐(MBPh4)是典型的大阴离子强电解质,由于其阴离子(BPh－4)具有较强的疏水作用,因此在水与有机混合溶剂中表现出与纯无机盐明显不同的热力学行为.水与叔丁醇(TBA)是一种特殊的混合溶剂,其性质已有很多报导[1－3].许多作者指出,在富水区存在着H2O与TBA分子形成的笼合物,这使该混合溶剂在富水区表现出许多反常特性,如蒸汽压、偏摩尔体积、密度等都出现了极大或极…     

Complex Formation of Crown Ethers and Cations in Water–Organic Solvent Mixtures: Part XII. Effect of the Acid–Base Properties of the Mixture on the Thermodynamic Functions of Complex Formation of Benzo-15-Crown-5 with Na<Superscript>+</Superscript> in Water–Methanol Mixtures at 298.15 K

The enthalpies of solution of benzo-15-crown-5 ether in methanol–water mixtures and methanol–water–sodium iodide systems have been measured at 298.15 K. The values of standard enthalpies of solution of benzo-15-crown-5 ether are positive in the mixtures of water and methanol within the whole range of mixture composition. The equilibrium constants of complex formation of benzo-15-crown-5 ether with the sodium cation have been determined by conductivity measurements at 298.15 K. The thermodynamic functions of the formation of these complexes have been calculated. The Gibbs energy of complex formation depends on the base–acid properties of methanol–water mixture.     

四苯硼钠在直链一元醇中的溶解度及其从水到醇中的迁移自由能

在288.15-328.15K, 用分光光度法测定了四苯硼钠在7种直链一元醇中的溶解度。计算并讨论了298.15K时, 四苯硼钠从水到醇中的标准迁移自由能及介质效应的大小。通过计算机曲线拟合, 给出了四苯硼钠的溶解度跟直链一元醇碳原子数及温度的关系,同时给出了298.15K时, 四苯硼钠的标准迁移自由能跟直链一元醇的介电常数和碳原子数的关系。     

Solvent extraction separation of rubidium with a crown ether for neutron activation analysis in rock samples

The extraction behavior of rubidium with a crown ether has been studied and methods for the separation and determination of rubidium have been developed. Rubidium was separated with tetraphenylborate from sample solution, and then quantitatively extracted into nitrobenzene by 18-crown-6 from 0.05 mol/l picric acid (pH 6) and back-extracted by 6 mol/l hydrochloric acid. Rubidium was determined by the neutron activation method in rock samples.     

Thermodynamic properties of normal and deuterated cyclopropenes

The specific heat, entropy, enthalpy, and Gibbs free energy of cyclopropene-d₀, cyclopropene-1-d₁, cyclopropene-3-d₁, cyclopropene-1,2-d₂, cyclopropene-3,3-d₂, cyclopropene-1,3,3-d₃, and cyclopropene-d₄ have been calculated for the temperature range 100–1500 K using the rigid-rotor and harmonic oscillator model. The standard enthalpy and Gibbs free energy of formation of cyclopropene-d₀ have also been evaluated for the same temperature range using the experimental standard enthalpy of formation at 298.15 K.     

Viscosity of Aqueous Solutions of Lithium,Sodium, Potassium,Rubidium and Caesium Cyclohexylsulfamates from 293.15 to 323.15 K

The viscosities of aqueous solutions of lithium, sodium, potassium, rubidium and caesium cyclohexylsulfamates were measured at 293.15, 298.15, 303.15, 313.15 and 323.15 K. The relative viscosity data were analyzed and interpreted in terms of the Kaminsky equation, η _r=1+Ac ^1/2+Bc+Dc ². The viscosity A-coefficient was calculated from the Falkenhagen-Dole theory. The viscosity B-coefficients are positive and relatively large. Their temperature coefficient ∂ B/∂ T is negative or near zero for lithium and sodium salts whereas for potassium, rubidium and caesium salts it is positive. The viscosity D-coefficient is positive. This was explained by the size of the ions, structural solute–solute interactions, hydrodynamic effect, and by higher terms of the long-range Debye-Hückel type of forces. From the viscosity B-coefficients the thermodynamic functions of activation of viscous flow were calculated. The limiting partial molar Gibbs energy of activation of viscous flow of the solute was divided into contributions due to solvent molecules and the solute in the transition state. The activation energy of the solvent molecules was calculated using the limiting Gibbs energy of activation for the conductance of the solute ions. The activation energy of the solvent molecules was then discussed in terms of the nature of the alkali-metal ions and their influence on the structure of water. The limiting activation entropy and enthalpy of the solute for activation of viscous flow were interpreted by ion-solvent bond formation or breaking in the transition state of the solvent. The hydration numbers of the investigated electrolytes were calculated from the specific viscosity of the solutions.     

四苯硼阴离子电子结构的理论研究

分别应用半经验发子轨道理论的AM1方法和在HF／3－21G水平上的从头算分子轨道法,对四苯硼阴离子的电子结构进行了研究。采用解析梯度技术对四苯硼阴离子的平衡态几何构型进行了全优化,得到了分子轨道、电荷布居、静电势以及红外光谱和紫外光谱等参数,计算结果表明：四苯硼阴离子的静电势分布均匀,其前线轨道能级间隔为12．1398eV,利用组态相互作用法得到的紫外光谱跃迁吸收峰主要位于远紫外区,说明四苯硼离子比较稳定,从头算法得到的红外光谱吸收峰分布与实验结果一致,AM1法得到的红外吸收频率与实验值更接近。     

Activity coefficients of rubidium chloride and cesium chloride in methanol–water mixtures and a comparative study of Pitzer and Pitzer–Simonson–Clegg models (298.15 K)

Activity coefficients of rubidium chloride and cesium chloride in methanol–water mixed solvent systems were determined by electromotive force (EMF) measurements at 298.15 K, in the range 0–40% (wt.%) methanol. For our work, the cells:

Rb-ISE | RbCl (m), methanol (Y), water (1 − Y) | Cl-ISE;  Cs-ISE | CsCl (m), methanol (Y), water (1 − Y) | Cl-ISE