混合电解质NaBr+NaAc十H_2O体系的活度系数的测定

用电势法测定了298.15K以及I为0.1、0.5、1.0、1.5、2.0、2.5和3.0 mol/kg时,NaBr在混合电解质溶液NaBr+NaAc+H_2O中的活度系数.实验结果用Harned、SRJ和Pitzer方程拟合,得到各种方程的相互作用参数,由拟合的标准偏差得知,Pitzer方程的拟合精度略好于前2个方程.用Pitzer混合参数θ_(Br-Ac)和ψ_(Br-Na-Ac)计算了NaAc在该混合体系中的活度系数和体系的过量Gibbs自由能.     

平均球近似法计算电解质活度系数的研究(Ⅱ)——混合电解质水溶液

用(I)报中所得到的阳离子有效直径参数,用平均球近似(MSA)法,在不用混合参数的条件下,预测了32个混合电解质水溶液的离子平均活度系教.预测的Inγ_± 与实验值的平均标准偏差为0.0113.文中还用Pitzer方程作了计算.结果表明本文预测结果比无混合参数的Pitzer方程好得多,接近于带混合参数的Pitzer方程的关联结果,作者还分别预测了各温度下4个混合电解质水溶液饱和浓度时的活度系数,结果令人满意.     

电势法研究NaBr在甲醇-水混合溶剂中298.15K下的热力学性质

用Na离子选择性电极NaBr(m),MeOH(w),H_2O(100-w)Br离子选择性电极组成的电池测定NaBr在甲醇含量为0%、10%、20%、40%、60%、80%、90%和100%的甲醇-水混合溶剂,浓度在0.01～3.0mol/kg之间的平衡电势.用Pitzer方程关联实验结果得到每个实验点的NaBr的平均活度系数.结果发现,在一定的溶剂比例下,NaBr的平均活度系数先随它的浓度增加而下降,然后上升;当NaBr浓度固定时,它的平均活度系数随溶剂中甲醇含量增加而下降.NaBr在甲醇中有微弱的缔合.     

电势法研究NaBr在甲醇-水混合溶剂中298.15K下的热力学性质

用Na离子选择性电极NaBr(m),MeOH(w),H_2O(100-w)Br离子选择性电极组成的电池测定NaBr在甲醇含量为0%、10%、20%、40%、60%、80%、90%和100%的甲醇-水混合溶剂,浓度在0.01～3.0mol/kg之间的平衡电势.用Pitzer方程关联实验结果得到每个实验点的NaBr的平均活度系数.结果发现,在一定的溶剂比例下,NaBr的平均活度系数先随它的浓度增加而下降,然后上升;当NaBr浓度固定时,它的平均活度系数随溶剂中甲醇含量增加而下降.NaBr在甲醇中有微弱的缔合.     

钠钙氯化物在乳糖水中热力学性质的确定

在298.15 K时利用电动势法确定四元体系氯化钠-氯化钙-乳糖-水不同组成(乳糖质量分数分别为0,5%,10%和15%)时的热力学性质。利用Pitzer离子作用模型拟合实验数据,获得了氯化钠和氯化钙在乳糖水混合溶剂中的Pitzer模型参数。进一步计算了氯化钠和氯化钙从纯水到乳糖水混合溶剂中的迁移吉布斯函数。获得了氯化钠和氯化钙混合电解质在乳糖水混合溶剂中的混合参数θ(Na Ca)和ψ(Na Ca Cl)。计算了298.15 K时四元体系中氯化钠和氯化钙的平均离子活度系数。结果发现:利用Pitzer高阶静电作用模型计算混合电解质在混合溶剂中的平均离子活度系数,能获得较为满意的结果。     

电动势法确定水-丙酮-氯化钠-氯化镁体系热力学性质

采用自行设计的无液体接界电池测定了多组分电解质在水溶液和混合溶剂中不同组成时电池的电动势.利用Pitzer模型拟合实验数据,获得电池的标准电动势E(○)及电解质的活度系数.此外,计算了电解质从纯水到混合溶剂中的迁移吉布斯函数,求得了Pitzer模型的计算参数.获得了NaCl和MgCl2混合电解质的混合参数θ(NaCl)...     

几种重要的热力学模型预测能力的比较研究

拟合了298.15K下Mn(NO3)2-H2O体系0~8.382mol·kg-1的各种热力学模型参数,其中包括原始Pitzer模型(三维里系数方程),扩展的Pitzer模型(五维里系数方程),Clegg-Pitzer模型以及BET模型。应用拟合的这些模型参数预测了该体系在各种温度和饱和浓度下水的饱和蒸气压,并把它们与实验值进行了比较。比较研究显示Clegg-Pitzer模型和BET模型均具有良好的预测能力,而各种版本的Pitzer模型则不尽如人意。     

色谱法研究三元系汽液平衡的尝试

本工作用沪产103型气相色谱仪测定了七种溶质在角鲨烷,邻苯二甲酸二壬酯及其混合物中的无限稀释活度系数,并用这些数据预测三元汽液平衡。工作方程为Flory—Huggins方程和Wilsoa方程。原理如下: 1.Flory—Huggins方程。将该方程分别应用于二元系及三元系: lnγ_(1(2))~∞=ln(V_1/V_2)+1-V_1/V_2+x_(12) (1) lnγ_(1(3))~∞=ln(V_1/V_3)+1-V_1/V_3+x_(13) (2) lnγ_(1(2+3))~∞=ln(V_1/V_(23))+1-V_1/V_(23)+x_(12)φ_2~2++x_(13)φ_3~2+(x_(12)+x_(13)-x_(23))φ2φ3 (3)式中γ_(1(2))~∞、γ_(1(3))~∞、γ_(1(2+3))~∞分别是溶质1在溶剂2和3以及混合溶剂2+3中的无限稀释活度系数,x_(ij)为ij分子对作用参数(Flory参数),V_4为i组份的液相摩尔体积,φ_i为i组份的体积分数。本工作假设溶剂混合时体积具有加和性,即V_(23)=x_2V_2+(1-x_2)V_3。     

氯化氢、水、甲醇三元体系汽液平衡的研究(Ⅰ)——氯化氢、水二元体系汽液平衡的测定及关联

用双循环型平衡釜测定了latm下盐酸体系的汽液平衡关系,所得数据与具有代表性的诸文献值作了比较和评价. 将Pitzer(1980年)方程简化成单参数形式,通过关联盐酸中水的活度系数,求得参数,然后推算其中氯化氢的活度系数及汽液平衡数据,结果与本文实测数据相一致,19组沸点的平均偏差为0.046℃、15组汽相组成(摩尔分率)的平均偏差为0.0020.     

连续滴加法快速测定混合溶剂中电解质的活度系数

改变通常的逐点称重配制溶液方法,用连续滴加的方法借助离子选择电极建立了混合溶剂中电解质较高浓度下活度系数的快速测定方法和装置。用以下电池: H~+玻璃电极|HCl(m),H_2O(1-x),MeOH(x)|AgCl-Ag电极测定了298.15K、溶剂比x=0,10,20,30,50,70,90％MeOH(wt)时的电动势,并用Pitzer方程关联出HCl的活度系数,同298.15K下的活度系数不同来源的文献值比较,表明本文测定方法和装置是可靠的,都能得到与之相一致的结果。     

用电势法测定混合电解质溶液中各个组分的活度系数

本文用无液接电势电池：Ｎａ－ＩＳＥ（或Ｋ－ＩＳＥ）｜（ＮａＣｌ（ｍＡ），ＫＣｌ（ｍＢ），Ｈ２Ｏ｜Ｃｌ－ＩＳＥ同时测定了２９８．１５Ｋ，溶液离子强度Ｉ：０．１、０．５、１．０、１．５、２．０和２．５ｍｏｌ／ｋｇ时，钠电极与氯电极组成的电池和钾电极与氯电极组成的电池的可逆电势值，根据Ｎｅｒｎｓｔ方程分别求出ＮａＣｌ－ＫＣｌ－Ｈ２Ｏ体系中，ＮａＣｌ和ＫＣｌ的平均活度系数。用Ｐｉｔｚｅｒ方程拟合两套实验数据，求出两套基本一致的Ｐｉｔｚｅｒ混合参数θＮａ－Ｋ和。将混合参数代回Ｐｉｔｚｅｒ方程，分别求出另一组分的平均活度系数，计算值与实验值比较，标准偏差分别为：０．００８１（ＮａＣｌ）和０．００７３（ＫＣｌ）。     

MBr(M=Na,K)在离子液体[Bmim]Br水溶液中的溶解度

为探索溴化1-丁基-3-甲基咪唑([Bmim]Br)离子液体对无机溴化物MBr(M=Na,K)在水中溶解度的影响,采用等温溶解平衡法在常压下测定了298.15~328.15 K范围内MBr在[Bmim]Br(1)+H₂O(2)溶液中的溶解度,考察了离子液体含量对溶解度的影响。实验结果表明,[Bmim]Br的加入会显著降低MBr(M=Na,K)在水中的溶解度,离子液体[Bmim]Br对KBr的盐析作用比对NaBr的盐析作用大。不同温度下的溶解度数据可用Pitzer混合电解质溶液模型进行关联,得到了混合离子相互作用参数以及MBr在混合溶剂中的平均活度因子和溶剂的渗透系数。模型计算的溶解度与实验结果吻合良好,平均活度因子和溶剂的渗透系数均随离子液体含量的增加而增加。     

TERNARY NaCl+LiCl+H2O MIXED ELECTROLYTE SYSTEM: DETERMINATION OF ACTIVITY COEFFICIENTS BASED ON POTENTIOMETRIC METHOD

The mean activity coefficients for NaCl in a ternary electrolyte system were determined by the potentiometric method, at 25°C, using a solvent polymeric (PVC) sodium-selective membrane electrode (Na⁺ ISE), containing N,N'-dibenzyl-N,N'-diphenyl-1,2-phenylenedioxydiacetamide as ionophore, and combined with an Ag/AgCl electrode. The potentiometric measurements were performed at the same ionic strengths in different series of mixed salt solutions, each characterized by a fixed salt molal ratio r (where r = m₁/m₂ = 1, 10, 50, 100). The nonideal behavior of the ternary NaCl(m₁) + LiCl(m₂) + H₂O electrolyte system was described based on the Pitzer ion-interaction model for mixed salts over the ionic strength ranging from 0.01 up to about 4 mol/kg. Two- and three-particle Pitzer interaction parameters for a mixed electrolyte system were determined based on potentiometric data, and the critical role of potentiometric selectivity coefficient (K₁₂) of ISE as limiting factor in the potentiometric measurements was analyzed.     

TERNARY NaCl+LiCl+H2O MIXED ELECTROLYTE SYSTEM: DETERMINATION OF ACTIVITY COEFFICIENTS BASED ON POTENTIOMETRIC METHOD

The mean activity coefficients for NaCl in a ternary electrolyte system were determined by the potentiometric method, at 25°C, using a solvent polymeric (PVC) sodium-selective membrane electrode (Na⁺ ISE), containing N,N′-dibenzyl-N,N′-diphenyl-1,2-phenylenedioxydiacetamide as ionophore, and combined with an Ag/AgCl electrode. The potentiometric measurements were performed at the same ionic strengths in different series of mixed salt solutions, each characterized by a fixed salt molal ratio r (where r = m₁/m₂ = 1, 10, 50, 100). The nonideal behavior of the ternary NaCl(m₁) + LiCl(m₂) + H₂O electrolyte system was described based on the Pitzer ion-interaction model for mixed salts over the ionic strength ranging from 0.01 up to about 4 mol/kg. Two- and three-particle Pitzer interaction parameters for a mixed electrolyte system were determined based on potentiometric data, and the critical role of potentiometric selectivity coefficient (K ₁₂) of ISE as limiting factor in the potentiometric measurements was analyzed.     

Activity measurements in aqueous mixed electrolyte solutions—III. HClCaCl2 mixtures of constant total ionic strength

Emf measurements have been made in cells without liquid junction of the type H₂/HX (m₁), MX_n(m₂)/AgCl, Ag . . (I) containing mixtures of HCl and CaCl₂ in different proportions, but at constant total ionic strength (I = 2, 1, 0.5). The measurements have been carried out at 5°C intervals over the temperature range 5–35°C. AgAgCl electrodes prepared by two different methods (thermal and thermoelectrolytic) were used of which the thermoelectrolytic electrodes were found to give more consistent results. The results when extrapolated properly lead to E° values at the different temperatures which agree well with those reported in literature. The application of the Pitzer method leads to the calculation of the ionic interaction coefficients α₁₂ and α₂₁, at the different constant ionic strengths. The nature of variation of these α's with the total mixture ionic strength at different temperatures has been considered.     

汽液平衡盐效应的分子热力学──乙醇-水-1-1型电解质系统恒压汽液平衡盐效应参数的计算

测定了6个乙醇-水-1-1型电解质系统（LiCl、LiBr、NaBr、NaAc、KCl、KI）恒压（100.8kPa）条件下的汽液平衡盐效应参数.在Pierotti定标粒子溶液理论基础上提出非电解质浓度任意变化条件下含盐双液系汽液平衡盐效应参数的计算方法.硬球作用项采用Masterton-Lee方程计算，软球作用项采用胡英等人建议的分子热力学模型计算．对于乙醇-水极性混合溶剂系统，离子-中心分子的碰撞直径考虑离子溶剂化的影响，以离子的溶剂化系数为可调参数，拟合出混合溶剂的局部介电常数与乙醇摩尔分数的关联方程．预测结果表明，在很大液相浓度范围（X_1=0.143～0.700）内14个乙醇-水-1-1型电解质系统52个盐效应参数的平均相对误差为7.76％     

Electrostatic Effect on Synergism of Wormlike Micelles and Hydrophobically Modified Polyacrylic Acid

The electrostatic effects on the synergism between wormlike micelles and hydrophobically modified polyacrylic acid (HMPA) have been investigated by rheological measurements and dissipative particle dynamics molecular simulation (DPD). Both cationic surfactants, cetyltrimethylammonium bromide (CTAB), and anionic surfactant, sodium oleate (NaOA), were employed to construct wormlike micelles, and the influences of both simple salts, NaBr or NaAc, and hydrophobic salts, sodium benzoate (NaBen) and benzyltrimethyl ammonium bromide (BTAB), were discussed. The synergistic effects vary with the headgroup charge and the counterions property of surfactants. For the NaOA system, the obvious viscosity maximum was observed only at low NaAc content, while a monotonous viscosity increase appeared at a high content of BTAB. However, the optimal synergism can be only observed in the presence of concentrated NaBen in CTAB system. DPD molecular simulation provides a support and favorable illustration for the synergism mechanism. It suggests that not only the hydrophobic interaction but also the electrostatic interaction has an important impact on the synergism between ionic wormlike micelles and HMPA.