四苯硼钾从水到水—乙醇混合溶剂中的标准迁移自由能

在２９８．在５Ｋ，对四苯硼钾在不同比例的水－乙醇混合溶剂顺的活度积及从水到混合溶剂中的标准迁移自由 能进行了研究，并对四苯硼钾在水－乙醇混合溶液中的介质效应进行了分析讨论 。     

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...     

四苯硼钾从水到水－乙醇混合溶剂中的标准迁移自由能

在２９８．１５Ｋ，对四苯硼钾在不同比例的水－乙醇混合溶剂中的活度积及从水到混合溶剂中的标准迁移自由能进行了研究，并对四苯硼钾在水－乙醇混合溶剂中的介质效应进行了分析讨论。     

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…     

KBPh4从水到直链一元醇中的标准迁移自由能

四苯硼钠（NaBPh4）与四苯硼钾（KBPh4）均属典型的大阴离子强电解质，并且具有相似的分子结构和相同的晶型［1］，但二者在溶液中的热力学行为却明显不同，为了系统和定量地研究二者在相同溶剂中热力学性质的差别，本文继前文［2］对KBPh4从水到7种直链一元醇中的标准迁移自由能进行研究．1实验部分1．1仪器与试剂UV－365型分光光度计（日本岛津制作所）；CS501型超级恒温槽（重庆实验设备厂）．NaBPh4和所用醇溶剂及提纯方法同前文［2］；KCl（S·P）；KBPh4是通过NaBPh4水溶液与过量5％的KCI水溶液反应而得，产物先经水洗涤…     

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…     

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.     

离子选择性PVC膜电极中溶剂化作用的研究 I: 碱金属离子由水相到TBP溶剂相的标准迁移自由能

电位法测量了碱金属离子由水相到TBP(磷酸三丁酯)-CH~3OH混合溶剂相的标准迁移自由能△G^0~t。研究了溶剂化作用同PVC膜对金属离子选择性的关系。碱金属离子的△G^0~t随着TBP在混合溶剂中含量的增加而增大。△G^0~t还随着离子半径的增大而增大, 这同TBP-PVC膜对碱金属离子的选择性次序相一致; 而与四苯硼酸盐-TBP-PVC膜对碱金属离子的选择性次序不完全相同。说明了TBP为溶剂的四苯硼酸盐膜对金属离子的选择性除了同溶剂化作用有关外, 还同膜相和水相中离子的交换反应常数等因素相关。     

应用离子选择性电极进行溶液热力学研究——Ⅴ.KCl在283.15K～318.15K间七个温度下由H_2O至DMF-H_2O混合溶剂的标准转移Gibbs自由能和转移熵的测定

本文应用Corning一价阳离子选择电极与氯离子选择电极组成无液接可逆电池,测定电池在283.15K～318.15K间七个温度下的标准电动势及其温度系数,计算KCl从纯水到相应的DMF-H_2O混合溶剂的标准转移Gibbs自由能ΔG_t~0和标准转移熵ΔS_t~0,得出ΔG_t~0和ΔS_t~0随混合溶剂中DMF的摩尔分数x_(DMF)及温度T的变化规律.发现KCl的ΔS_t~0随x_(DMF)变化的趋势和NaCl的相反.从离子溶剂化作用及其对溶剂结构的影响作了讨论.     

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.     

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

Solubilities of ribidium tetraphenylborate in water,methanol,ethanol,1-propanol,1-butanol,l-pentanol,1-hexanol and 1-octanol at 288.15,298.15,308.15,318.15,328.15 K have been determined by spectrophotometry.The standard Gibbs energy of transfer of ribidium tetraphenylborate from water to straight-chain n-alkanols and the primary medium effect of rubidium tetraphenylborate from 288.15 to 328.15 K have been calculated.Furthermore,the contribution of microscopic interactions to the standard Gibbs energy of transfer of rubidium tetraphenylborate is calculated and discussed.     

Evaluation of Excess Gibbs Energy of Mixing in Binary Mixtures of Di-Isobutyl Ketone (Dibk) and Nonpolar Solvents

Abstract

Excess Gibbs energy of mixing in binary mixture of Di-isobutyl ketone (DIBK) in nonpolar solvents namely n-heptane, p-xylene, cyclohexane, dioxane, benzene and tetra-chloromethane have been evaluated at 303°K. The results indicate that (ΔG_AB)_maxima is in the order, n-heptane > p-xylene > cyclohexane > benzene > dioxane > tetra-chloromethane.     

Ions in Aqueous Acetic Acid Mixtures: Solvent Reorganization around Protons and Gibbs Energies of Transfer from Water

The photo-absorbing, basic sensor, 4-nitroaniline, has been used to determine theequilibrium constant for solvent reorganization around the proton in mixtures ofvarying composition of water with acetic acid. In all the mixtures used, theself-ionization of the acetic acid was suppressed. In contrast to mixtures of waterwith the related ethanol or acetone, this equilibrium is shifted more toward thewater-solvated species as the mole fraction x ₂ of the cosolvent increases. TheGibbs energy of transfer of protons from water into the mixture G ^o _t (H⁺) can bederived with the aid of this equilibrium constant for the solvent reorganization.Using G ^o _t (H⁺), G ^o _t (i) for i denoting anions and other cations can be evaluated.In comparison the G ^o _t (i) for cations have lower negative values than when eitherethanol or acetone is added to water. Correspondingly, for halide anions, thepositive G ^o _t (i) with added acetic acid are rather less than is found with eitherethanol or acetone added. The influence on the ion-solvent interaction of bothelectron withdrawing hydroxy and carbonyl groups in acetic acid may beresponsible for this. Although G ^o _t (i) for C10^– ₄ and Re0^– ₄ are also positive, both picrateions and OH^– give negative values with acetic acid added to water. With picrateions, the hydrophobic effect of the carbon ring produces stabilization in themixture relative to water. With OH^–, complete conversion to acetate anionsoccurs. As is found with other cosolvents, the contribution of the charge onacetate anion to G ^o _t (CH₃COO^–) is found to increase as x ₂ rises. The aciddissociation constant K _a for acetic acid is found to decrease slowly as x ₂ rises to0.5, followed by a rapid decrease for x ₂ greater than 0.7 where dimerization ofacetic acid occurs.     

In(Ⅲ)的标准迁移吉布斯自由能

通过直流极谱法对In(Ⅲ) 从纯水到蔗糖及葡萄糖水溶液的标准迁移吉布斯自由能(GtΘ)进行了研究，根据In(Ⅲ)的可逆半波电位和扩散系数求得GtΘ.实验表明, GtΘ随蔗糖及葡萄糖浓度的增加而逐渐减小,说明In(Ⅲ)在蔗糖及葡萄糖水溶液中的稳定性增加. GtΘ可分为静电能和化学能两部分，化学能逐渐降低表明蔗糖及葡萄糖水溶液比纯水碱性强.根据三元体系中溶质-溶剂和溶质-溶质的相互作用对实验结果进行了讨论.