电导法对几种液晶冠醚与KClO_4络合作用的研究

近年来国内外相继报道了在冠醚核心上引入取代基合成出一系列具有液晶特性的冠醚化合物,它们除具有普通液晶的电光、电磁及超声等特性外,还具有选择性络合金属离子的能力。研究这类化合物结构及性能将有助于选择和制备对金属离子具有高度识别能力的输送膜。为此,我们研究了以二苯并-18-冠-6(DB-18-C-6)及苯并-15-冠-5(B-15-C-5)为核心衍生的胆甾型冠醚化合物。经红外、核磁、质谱及元素分析确定其结构,由差热分析和偏光显微镜观察证明其具有液晶特性,并用电导法探讨了该系列液晶化合物与KClO_4在25℃时的络合特性,测定了络合比及络合常数。     

四丁基氟化铵在H2O-DMF中的电导研究

测量了298.15~328.15 K温度范围内四丁基氟化铵在20(wt)%~80(wt)%H2O/DMF混合溶液中的电导率,测得的电导率分别通过Kray-Bray方程和Shedlovsky方程分析,推导出了四丁基氟化铵在H2O-DMF混合溶液中的摩尔极限电导、缔合常数和离解常数,并计算出缔合反应的热力学参数(△Ga,△Ha,△Sa);同时探讨了温度和混合溶剂的组成对摩尔极限电导、缔合常数和热力学参数的影响。     

二甲基甲酰胺中钐盐的电导研究

通过电导测量研究了4种钐盐:Sm(CF3SO3)3,Sm(ClO4)3,Sm(NO3)3,和SmCl3在极性非质子溶剂DMF中的电导性质。利用线性拟合方法求得在25℃下Sm(CF3SO3)3和Sm(ClO4)3的极限摩尔电导率分别为274 5和283 2S·cm2·mol-1。用间接方法求得Sm(NO3)3与SmCl3的极限摩尔电导率分别为299 7,289 8S·cm2·mol-1。在25～65℃温度范围内,Sm(CF3SO3)3和Sm(ClO4)3的电导率随温度呈线性变化。Sm(NO3)3,SmCl3的电导行为表现出明显的离子缔合。     

混合电解质的电导测定

电导测定为研究离子与离子之间的缔合效应、离子与溶剂的相互作用及溶剂结构提供了一个有效手段 .目前 ,电解质水溶液、电解质非水溶剂体系的电导数据却很缺乏 ,而混合电解质体系的电导测定在理论及应用方面都很重要 .作为全面系统地考察金属氯化物的混合电解质的电导性质变化规律 ,前文已测定了 Na Cl- KCl- H2 O体系 [1] 、 Na Cl- Rb Cl- H2 O体系及 KCl- Rb Cl- H2 O体系的电导值 [2 ] ,本文用自行设计的电导池测定了 Ca Cl2 - H2 O,Ca Cl2 - Na Cl- H2 O,Ca Cl2 - KCl- H2 O体系在 2 98.1 5 K时的低浓度电导数据 ,探讨了…     

MeOH-H~2O-NaOAc体系(278.2~318.2K)的电导研究

本文测定了278.2~318.2K间的五个温度下七种浓度的NaOAc分别在10, 20,30, 40, 50, 60, 70, 80, 90及100%MeOH-H~2O体系中的摩尔电导Λ, 并应用FOS,Pitts, L-W, F-78等四个电导方程对实验数据进行了拟合处理, 得到了三个拟合参数Λ~O, K~Λ及R(或α)。最后, 对四个方程与实验的吻合程度, 温度、溶剂组成等对Λ~O、K~Λ的影响规律及溶质-溶剂相互作用进行了讨论。     

PrOH-H2O混合溶剂中LiCl,NaCl的电导研究

本文设计并制作一套可搅拌U型电导池, 并用其测定了LiCl, NaCl在PrOH-H2O二元混合溶剂中的摩尔电导。应用Fuoss-Onsager电导方程关联得到Λ。, a°及Ka, 并据此探讨了LiCl, NaCl-PrOH-H2O的微观结构及相互作用。     

NaCl在CH~3OH-H~2O混合溶剂中活度系数的测定(298.15K)

用电动势法测定了298.15K时,由Na^+和Cl^-离子选择电极组成的电池在NaCl-CH~3OH-H~2O混合体系中的电动势,用扩展的Debye-huckel方程和Pitzer方程关联不同溶剂组成下电动势的实验值,得到电池的标准电动势能和NaCl 在混合溶剂中的活度系数.将Pitzer-Simonson方程应用于含离子缔合体系.求出NaCl 在混合溶剂中的缔合常数,结果表明NaCl在甲醇含量为60%时,可能已有离子对生成     

二甲基甲酰胺中四种钕盐的电导

通过电导测量研究了四种钕盐：Nd(CF3SO3)3、Nd(ClO4)3、Nd(NO3)3和NdCl3在极性非质子溶剂DMF中的电导性质.利用线性拟合方法求得在25 ℃下Nd(CF3SO3)3和Nd(ClO4)3的极限摩尔电导率分别为278.8和 280.7 S•cm2•mol－1.用间接方法求得Nd(NO3)3 与NdCl3 的极限摩尔电导率分别为297.2和287.3 S•cm2 •mol－1.在25～65 ℃温度范围内，Nd(CF3SO3)3和Nd(ClO4)3的电导率随温度呈线性变化. Nd(NO3)3和NdCl3的电导行为表现出明显的离子缔合.     

非水溶剂中稀土离子和穴醚（2.2）配合物的电导研究

用电导法研究了２５℃时，硝酸稀土和穴醚在不同溶剂中的配位行为。计算了１：１配合物的稳定常数及摩尔电导率，在非水溶剂（ＣＨ３）２ＣＯ．ＣＨ３ＣＮ．ＣＨ３ＯＨ和ＤＭＦ中，由于配位过程中伴随着Ｌｎ离子的溶剂化作用，稀土和穴醚配合的稳定常数随Ｌｎ原子序数的增加而变化不大。     

在i-PrOH-H2O混合溶剂中硫酸镁离子对缔合热力学研究

50年代,Nair等利用电动势法研究了硫酸镁离子对缔合过程的热力学量,Chand等也对水溶液中硫酸镁离子对的性质做过研究,宋彭生和孙柏对硼酸镁和硼酸钙离子对做了研究,目前,还没有人研究有机溶剂对[MgSO4]^0离子对标准缔合常数Kb的影响,本文在278.15-318.15K温度范围内,测定了无液接电池（A）,（B）的电动热E：Pt,H2(101.325kPa)|(HCl(m1),H2SO4(m2),i-PrOH(x),H2O(1-x)|AgCl-Ag(A) Pt,H2(101.325kPa)|(HCl(m1),MgSO4(m2),i-PrOH(x),H2O(1-x)|AgCl-Ag(B)其中,mi为物质i的质量摩尔浓度,x表示异丙醇i-PrOH在混合溶剂中的摩尔分数,保持x=0.05。利用电池A的电动势,在Debye-Hueckel理论基础上,确定了H2SO4在混合溶剂中的二级标准解离常数K2;利用电池B的电动势,确定了[MgSO4]^0离子在对沸合溶剂中的标准缔合常数KD,根据实验结果计算了离子缔合熵和焓,讨论了异丙醇对KD的影响,指出离子缔合熵是形成离子对的推动力。     

A Study on the Gonductance of KBr. KSCN. KClO4 and KI in the Mixed Solvent of Dimethylformamide and 1,4-Dioxane

This paper reports the measured conductance of KBr,KSCN.KClO4 and KI in the mixed solvent of DMF with 1,4-dioxane at various ratios,the viscosity of the mixed solvent and the density of the salt solution.According to the conductance equations,namely,Pitts equation,Fuoss-1978 equation and Lee-Wheaton equation,the experi-.mental data were fitted on computer to get the limit molar conductance of salt at infinite dilution the ionic association constant Ka,and the distance parameter between cation and anion R.The suitability of the theoretical equations and the interaction of ion-ion-solvent molecule were discussed.     

Excess Molar Volumes and Thermal Expansivities of Aqueous Solutions of Dimethylsulfoxide,Tetrahydrofuran and 1,4-Dioxane

Densities, , of the systems water (W) + dimethylsulfoxide (DMSO), W + tetrahydrofuran (THF) and W + 1,4-dioxane (DO) have been determined in the temperature range 303.15-323.15 K. Excess molar volumes, $V_m^E $ , have been found to be negative and large in magnitude. Thermal expansivities, f , and excess thermal expansivities, f E , have been calculated. Densities, excess molar volumes, thermal expansivities and excess thermal expansivities have been plotted against mole fraction of solutes. All these properties have been expressed satisfactorily by appropriate polynomials. Attempt has been made to explain $V_m^E$ in terms of hydrophobic hydration and hydrophilic effect of the solutes.     

Prediction of the Conductance of Strong Electrolytes and the Calculation of the Ionization Constant of Weak Electrolytes in a Dilute Solution by a New Equation

In order to predict the conductance for dilute 1-1 valent electrolyte solutions,a new conductance equation was proposed based on the Onsager and Onsagar-Fuoss-Chen conductance equation.It has only one parameter A,which can be obtained directly from the data of ionic limiting molar conductivity Λ∞m,and its expression is very simple.The new equation has been verified by the experimental molar conductivities of some single strong electrolyte and mixed electrolyte solutions at 298.15 K reported in literatures.The results are in good agreement with the experimental data.Meanwhile the ionization constants of some weak electrolyte solutions were calculated by a modified equation of this new equation,and it was also found that the calculation results are in good agreement with the data in the literature.     

高效毛细管电泳电导检测对阴离子表面活性剂分离测定的研究

以Ca2 +为分离介质 ,甲酰胺为添加剂 ,通过对缓冲体系、缓冲液浓度、酸度、Ca2 +浓度、甲酰胺浓度、电泳电压和进样时间的优化选择 ,用毛细管电泳 -电导检测法分离了十二烷基硫酸钠(K12)和十二烷基苯磺酸钠(LAS) ;在10mmol/LTris -11mmol/LCit(pH4.5)运行缓冲液中 ,上述两组分在16min内完全分离 ;K12和LAS的线性范围分别为5.0×10-6～8.0×10-3 mol/L和5.0×10-6 ～5.0×10-3 mol/L ;检出限(S/N=3)分别为2.5×10-6 和3.0×10-6 mol/L,应用于合成洗衣粉样和合成水样中K12 和LAS测定 ,结果令人满意。     

Thermodynamics of Ion-Association of NaClO4 in Aqueous-Methanol and Aqueous-Glycerol Using Conductance Measurements

The conductance of NaClO₄ at (25–45)°C in methanol-H₂O, and glycerol-H₂O mixtures in a concentration range up to 10^?2 M has been measured. The association constant, K_A, values have been determined, where the conductometric data were analysed by a M S X computer using the Fuoss-Aprano method. The K_A values for NaClO₄ in methanol-H₂O are higher than in glycerel-H₂O mixtures, Also K_A values increase as the proportional of methanol or glycerol increases in mixture. The thermodynamic parameters ΔH°, ΔG°, and ΔS° were also calculated. It is obvious that the entire process of the ionic association in those systems are endothermic ones. The Walden products, Λ_oη were calculated for all systems investigated.     

Conductance and Thermodynamic Study of the Complexation of Ammonium Ion with Different Crown Ethers in Binary Nonaqueous Solvents

A conductance study of the interaction between ammonium ion and 18‐Crown‐6 (18C6), dicyclohexano‐18‐crown‐6 (DC18C6), ditertbutyl‐dicyclohexano‐18‐crown‐6 (t‐bu)₂DC18C6, diaza‐15‐crown‐5 (DA15C5), dibenzo‐21‐crown‐7 (DB21C7) and N‐Phenylaza‐15‐crown‐5 (NPA15C5) in acetonitril‐di‐methylsulfoxide mixture was carried out at various temperatures. The formation constants of the resultant 1:1 complexes were determined from the molar conductance‐mole ratio data and found to vary in the order of DA15C5 > DC18C6 > 18C6 > (t‐bu)₂DC18C6 > DB21C7 > NPA15C5. The enthalpy and entropy of the complexation reactions were determined from the temperature dependence of the formation constants.     

Conductance behaviour of HCl in water-ethylene glycol, water-diethylene glycol and ethylene glycol-diethylene glycol mixtures

The conductance behaviour of HCl in water-ethylene glycol, water-diethylene glycol and ethylene glycol-diethylene glycol mixtures was investigated in the complete range of solvent compositions of 25°C by applying the three-parameter conductance equation. No appreciable association of the acid was observed in any of the mixed solvents. The large decrease ofΛ ₀ andΛ ₀ η ₀ of the acid in the early and end composition region of the mixed solvents has been attributed to the drastic structural changes brought about by the addition of the organic component in the aqueous solvent mixtures and by the addition of diethylene glycol in the case of ethylene glycol-diethylene glycol mixtures.     

The conductance of tetrabutylammonium lodide in toluene-acetonitrile mixtures at 15, 25, and 35°C

Association constants and the limiting molar conductances have been evaluated for Bu ₄ NI in acetonitrile-toluene mixtures at 15, 25 and 35°C. The experimental data were analyzed by means of the Lee-Wheaton equation. The thermodynamic parameters for the noncoulombic interactions were evaluated.     

Conductance of electrolytes in dipolar aprotic solvent mixtures. I. Conductance of lithium chloride in mixtures of methylethylketone and acetone with N,N-dimethylformamide at 25°C

The conductances of LiCl in acetone-N,N-dimethylformamide (AC-DMF) and methylethylketone-N,N-dimethylformamide (MEK-DMF) binary mixtures have been measured at 25°C. The data were fitted to the 1978 Fuoss equation to obtain ion association constants K_A and limiting molar conductances ₀. The Bjerrum ion association theory modified by Fernandez-Prini and Prue was also used for evaluation of K_A and a, the contact ion-pair distance. LiCl is more associated in AC-DMF mixtures than in the MEK-DMF system. Addition of DMF to either AC or MEK decreases K_A and ₀ as expected from the increase in the dielectric constant and the viscosity. The distance parameter a is almost constant and equal to 2.6 A in these mixed solvent systems. The Walden products pass through minima in both ketone-rich regions.