Borate buffer equilibria in nickel refining electrolytes

Buffer capacity studies, carried out using pH titrations, demonstrated that electrolytes containing NiSO₄ + H₃BO₃ + Na₂SO₄ buffer more effectively than in the presence of H₃BO₃ + Na₂SO₄. The increased buffer capacity is dependent on the concentration of both Ni²⁺ and H₃BO₃. Thermodynamic analysis of the pH titration data suggested the formation of a weak complex, Ni(H₂BO₃)₂, (logK 3.8 to 4.9) between Ni²⁺ and H₃BO₃ in mixed chloride-sulphate electrolytes at 55° C.     

Electrical noise in aqueous 1-1 electrolytes

An equivalent noise conductivity Λ_n for aqueous uni-univalent electrolytes is defined on the basis of the Langevin equation. Apparatus for the recording of noise spectra and their evaluation by means of correlation methods are described. It is shown that Λ_n of NaCl and of KCl solutions parallels that obtained by conventional bridge methods though no external electric field as applied in the case of noise measurements. Λ_n for both these electrolytes is shown to obey the Debye—Hueckel—Onsager limiting law in its concentration dependence and to exhibit the usual Arrhenius form of temperature dependence. The activation energy obtained is close to that obtained from conventional bridge methods applying an external field, and closely approximates that of the viscosity of the solvent, viz. water. The noise generated by the electrolyte is shown to be white noise, being independent of frequency without any 1/f frequency component being present. There is no contact noise.     

Thermal properties of acetylacetone

The vapour pressure of acetylacetone has been measured over the temperature range 297–398°k. The results are summarised as: Heat capacity measurements have been carried out on the enol form of acetylacetone over the temperature range 80–300° k. An estimate has been made of heat capacity values below 80° k. Entropy, enthalpy and free energy values have been derived and are listed at ten degree intervals. The melting point (254·80°0·05° k) and heat of fusion (144·8°0·5 abs.Jg^?1) of the enol form have been determined. The results have been used in conjunction with previously published data to evaluate the entropies and the heats, entropies and free energies of formation of the keto and enol forms of acetylacetone in the gaseous and liquid phases at 298·16° k.     

取代苯甲酸类化合物在正辛醇中的固液平衡

The solid-liquid equilibrium of benzoic acid derivatives in 1-octanol was first determined in this article. Using a laser monitoring observation technique, the solubility data of o-amino-benzoic acid, p-amino-benzoic acid,o-chloro-benzoic acid, and m-nitro-benzoic acid in 1-octanol were measured by the polythermal method in the temperature range of 20-50℃. The experimental data were regressed with the. Wilson equation and the λH equation. The experimental results showed that the solubility of the four chemicals in 1-octanol increased significantly with temperature. The results indicate that the molecular structure and interactions affect the solubility significantly.The solubility order of the benzoic acid derivatives is as follows： m-nitro-benzoic acid〉o-chloro-benzoic acid〉 o-amino-benzoic acid〉p-amino-benzoic acid. Both the Wilson equation and λH equation are in good agreement with the experimental data.     

乙酰丙酮金属化反应研究

以乙酰丙酮为配体,分别与过渡金属氧化物Fe2O3、Co2O3、CuO反应,合成了3种乙酰丙酮的过渡金属配合物。通过元素分析、红外光谱、紫外-可见光谱、核磁共振波谱等测试手段对配合物进行了结构表征,确定了配合物的可能结构,并对其催化性能进行了初步探讨。     

Conductivities and ion association of 1:1 electrolytes in aprotic solvents

Molar conductivities for several alkali metal salts and tetraalkylammonium salts have been measured at 25°C in 4-butyrolactone and propylene carbonate over the concentration range of 0.01–0.001 mol dm^?3. The data were analysed by Justice's method, and the results compared to corresponding data for acetonitrile solutions. From a consideration of dielectric constants, ion pairing is expected to be similar in 4-butyrolactone and acetonitrile solutions. However we find that ion pair formation in 4-butyrolactone is very similar to that in propylene carbonate. When interpreted in terms of the Bjerrum treatment of ion pair formation, this behaviour can be attributed to the formation of solvent separated ion pairs in 4-butyrolactone whereas in propylene carbonate and acetonitrile, all salts form simple “contact” ion pairs.     

Vapor-liquid equilibria of solvents in mixed strong 1 : 1 electrolytes-solvent system

Phase equilibrium calculation of electrolyte-mixed solvent systems is important in separation processes including extractive distillation. Although methods for equilibrium calculations are available in the literature, they are specific to each application and no general methods have been proposed. In the present work we extented the semiempirical method applicable to the solute properties of mixed electrolyte-mixed solvent systems to the calculation of solvent properties. In the present method excess Gibbs function was represented as the sum of Debye-Hückel term, Born term and NRTL term. Experimental data for mixed 1 : 1 strong electrolytes-mixed solvent systems showed close agreements with calculated values.     

Conductivities and ion association of 1:1 electrolytes in mixed aprotic solvents

Molar conductivities of the 1:1 electrolytes LiClO₄, LiAsF₆, n-Bu₄NClO₄ and n-Bu₄NBPh₄ were measured in mixtures of propylene carbonate and dimethoxymethane over the concentration range 0.01?1 × 10^?4 mol dm^?3. In all cases a maximum in molar conductivity (and hence in electrolytic conductivity) is observed in a solvent mixture having a composition of around 40 mass % propylene carbonate. Molar conductivities at infinite dilution (Λ^∞) and thermodynamic ion association constants (K^∞_a) were evaluated from these data. Single ion molar conductivities (λ^∞_i) were evaluated using the assumption that λ^∞(n-BuN⁺₄) = λ^∞(BPh^?₄). In order to account for the observed conductivity behavior it is necessary to assume that lithium salts from solvent separated ion pairs in ethereal solvents. All other salts from contact ion pairs.     

Solubilities of mixed strong 1:1 electrolytes in water and water-methanol mixtures

A model [1] recently proposed for mixed electrolytes-mixed solvent systems was tested for activity coefficients of electrolytes, the transfer Gibbs free energy and the solubilities of electrolytes. The model is comprised of the Debye-Hückel term, the Born term and the NRTL term similar to Cruz and Renon’s. but has several simplifying features. The model was found applicable to mixed electrolyte-aqueous systems without any interaction parameter between electrolytes. But since the available data are limited, the test for applicability to mixed solvent systems needs further studies.     

Ion-solvent interactions - studies on the solvation of electrolytes in mixed solvents

In order to throw light on ion-solvent interactions, the solvation numbers of electrolytes in different mixed solvents (methanol + water and ethanol + water mixtures) have been determined using ultrasonic interferometer. The anomalies in the solvation number of cations (in aqueous solutions) like K⁺, Na⁺ and H⁺ are presented. The changes in the solvation numbers of electrolytes with increasing quantities of alcohol indicates some interesting features and are explained on the basis of:(i) decrease in the solvent molecules.(ii) structural re-arrangement.(iii) preferential solvation of cations and anions.(iv) Approximations in the determination of solvation numbers. The role of the solvents could hardly be explained in absence of a complete knowledge of the nature of solvation of electrolytes and particularly of ions. The subject has attracted considerable attention and the solvation number has been determined using different well-known techniques[1-4].In order to throw light on the ion-solvent interactions, we tried to determine the solvation numbers of different known electrolytes like HCl, NaCl and KCl in water, methanol + water and ethanol + water mixtures by the compressibility method using ultrasonic interferometer. The results are presented in this communication.     

Vapor-liquid equilibria of some pollutants in aqueous and saline solutions part II: correlation for dilute weak electrolytes in aqueous buffered solutions

A thermodynamic procedure is described for predicting vapor-liquid equilibria in buffered, dilute aqueous solutions containing one weak electrolyte: ammonia, hydrogen cyanide, formic acid, acetic acid, pyridine or aniline.The procedure requires the dissociation constant of the weak electrolyte and either the Henry's constant or a vapor-liquid equilibrium ratio (K') determined for a dilute weak electrolyte solution in a pH region where most of the electrolyte is not ionized.Predicted results agree well with experiment. The thermodynamic procedure described here is effective for estimating phase equilibria for weak electrolyte pollutants in sea water or waste water as encountered in desalting plants or pollution abatement processes. The correlation is also useful in the design of secondary refrigerant freezing processes which utilize a direct contact melting-condensing system. In this scheme the volatiles present in the feed would be stripped out of solution by the evaporating refrigerant and then reintroduced to the product water.     

1-环丙基-7-氯-6-(1-哌嗪基)-4-氧-1,4-二氢-3-喹啉羧酸盐酸盐的熔化与离解性质研究

1－环丙基－7－氯－6－（1－哌嗪基）－4－氧－1，4－二氢－3－喹啉羧酸盐酸盐为环丙沙星合成中主要的杂质之一，研究其物化性质对于改善环丙沙星的结晶分离提纯具有重要意义。本文研究了1－环丙基－7－氯－6－（1－哌嗪基）－4－氧－1，4－二氢－3－喹啉羧酸盐酸盐的熔化，分解特性，溶解度与离子强度，温度和pH值的关系，并测定了该物质的离解常数，估算了该物质在水溶液中的活度积。     

R-（＋）-2-（4-羟基苯氧基）丙酸离解常数的测定

R-( )-2-(4-羟基苯氧基)丙酸(HPPA)是合成除草剂炔草酯的重要中间体.在分离和纯化工艺中,需要调节溶液的pH值控制HPPA各种存在形式的分布系数.然而文献上未见HPPA离解常数的报道,为此用pH计测定酸碱滴定法测定THPPA的离解常数pKa1和pKa2,并进行不确定度评定.结果报告如下:被测量pKa1和pKa2分别为3.10和10.25;合成标准不确定度为0.021和0.019;有效自由度为4.2和4.4;包含因子(置信概率为0.95)均为2.7;扩展不确定度为0.06和0.05.据此讨论了相关的工艺.     

Electrochemical investigation of polymer electrolytes based on lithium 2-(phenylsulfanyl)-1,1,2,2-tetrafluoro-ethansulfonate

The salt PhSCF₂CF₂SO₃Li appears promising for lithium-polymer batteries. Its poly(oxyethylene) complexes, although less conductive than lithium imide complexes, provided cationic transference numbers ranging between 0.45 and 0.5, enabling high cationic conductivities to be obtained. Thanks to its double substitution by aryl and perfluorinated moieties, the thioether function is stable enough to be used with positive electrodes, such as vanadium oxide and perhaps cobalt oxide.     

Vapor—liquid equilibria of acetonitrile-1-propanol mixtures

Experimental P-T-x data have been measured for acetonitrile-1-propanol mixtures. The Margules, UNIQUAC, UNIFAC and ASOG models and the method of Mixon et al. have been used to predict the vapor compositions from the P-T-x data. A good agreement has been found between the vapor compositions predicted by the above except in the case of UNIFAC. The parameters obtained by using the single set data treatment gave satisfactory representation of vapor liquid equilibria of acetonitrile-1-propanol mixtures.     

Ion association of (1:1) electrolytes in pure alcohols at 25°C

Conductances of S-n-buis Br, S-n-amis Br, S-meis I, S-n-buis I, S-n-amis-I, S-n-heptis I, S-n-pris Pi, S-n-buis Pi, S-n-amis Pi and S-n-heptis Pi are reported in EtOH, n-PrOH and n-BuOH. The results are analyzed using the Fuoss and Onsager equation (1959) to obtain the three characteristic parameters; conductance at infinite dilution Λ₀, contact distance å and association constant K_A. The results are also analyzed using Fuoss' equation (1975-1977), from which the true values of Λ₀, the cosphere diameter R and K_A are obtained.     

The electrochemical redox processes in methacrylate-based polymer electrolytes II. - Study on microelectrodes

The electrochemical behaviour of ferrocene was studied in different gel polymer electrolytes based on methyl, ethyl and 2-ethoxyethyl methacrylate and compared to the liquid aprotic solution (propylene carbonate). Voltammetric and chronoamperometric measurements on microelectrodes were conducted in order to describe the qualitative as well as quantitative behaviour of ferrocene in different conditions. Heterogeneous electron-transfer rate constants and diffusion coefficients of ferrocene in polymer electrolytes were estimated to be 1.1-7.8 × 10⁻³ cm s⁻¹ and 4-13 × 10⁻⁸ cm² s⁻¹ depending on the electrolyte composition. The influence of the polymer polarity, ferrocene concentration and level of polymer cross-linkage on the kinetics of ferrocene oxidation and its transport was discussed. The electrolytes with poly(2-ethoxyethyl methacrylate) exhibit the highest ionic conductivity (2-4 × 10⁻⁴ S cm⁻¹) as well as diffusion coefficient of ferrocene (1.3 × 10⁻⁷ cm² s⁻¹) in their structure.     

常压下正丁醇-异丁醇-醋酸丁酯-水体系汽液平衡测定与关联

文章采用单级循环汽液平衡釜测定了常压条件下正丁醇-异丁醇-醋酸丁酯-水混合液中的二元体系的汽液平衡数据,运用试差法关联Wilson方程中六对二元体系的模型参数,并计算出相应的汽相组成;测定了常压条件下正丁醇-异丁醇-醋酸丁酯-水四元体系的汽液平衡数据,并由六对二元体系模型参数关联出四元体系的汽液平衡数据。比较实验和计算值,结果表明:实验值与计算值的相对偏差均≤5%,说明实验值与计算值一致。文章研究结果为正丁醇、异丁醇、醋酸丁酯及水混合液的分离提供了一定基础数据。     

High-temperature C1-gas fuel cells using proton-conducting solid electrolytes

With proton-conducting solid electrolytes based on SrCeO₃ or BaCeO₃, high-temperature fuel cells were constructed and cell performances were examined. Mixtures of water vapor and some C₁ gases such as methanol vapor or methane were used as fuel by internal reforming to liberate hydrogen in the anode compartment. These fuel cells worked stably above 900°C. Addition of water vapor to the fuel was necessary to prevent carbon deposition at the anode. The performances of the cells were limited mainly by ohmic resistance of the solid electrolyte.