Application of the Prigogine-Flory-Patterson theory part III. Mixtures of a bicyclic compound,benzene, cyclohexane,n-hexane with a cycloalkane,cyclohexene, a cycloalkadiene and benzene

The Prigogine-Flory-Patterson theory of liquid mixtures has been qpplied to the H _m ^E and V _m ^E for binary mixtures of a bicyclic compound, benzene, cyclohexane and n-hexane with a cycloalkane, cyclohexene, a cycloalkadiene and benzene. Furthermore the Prigogine-Flory theory has been used to predict activity coefficients at infinite dilution from the experimentally determined H _m ^E at 25°C for the mixtures cyclohexane, cyclohexene, 1,3-cyclohexadiene, 1,4-cyclohexadiene and benzene with a bicyclic compound. The predictions are compared to experimental results.     

Electrochemical dissolution of magnetite in acid solutions

The present paper deals with the electrochemical behavior of magnetite microcrystals in an acid medium. A voltammetric method employing a carbon-paste electroactive electrode (CPEE) with an organic binder was used. It was found that the cathodic voltammograms, which were recorded at different scan rates, formed a set bounded in the space of i–E parameters by a generalizing voltammetric curve corresponding to the effective potential scan rate _eff. In other words, all curves are situated under one enveloping curve, just as the smaller dolls sit in the largest doll of a Russian doll. Reverse currents (a cathodic current in the anodic direction of the potential scan) were observed on the cyclic voltammogram. Forward and reverse currents obey the same laws and have one and the same generalizing curve, which could be taken as the magnetite characteristic.     

Measurement and prediction of activity coefficients at infinite dilution (γ), vapor–liquid equilibria (VLE) and excess enthalpies (H) of binary systems with 1,1-dialkyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide using mod. UNIFAC (Dortmund)

Activity coefficients at infinite dilution (γ^∞), vapor–liquid equilibria (VLE) and excess enthalpies (H^E) were measured for alkanes and alkenes in the ionic liquids 1-butyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [BMPYR]⁺[BTI]⁻, 1-hexyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [HMPYR]⁺[BTI]⁻ and 1-octyl-1-methyl-pyrrolidinium bis(trifluoromethylsulfonyl)imide [OMPYR]⁺[BTI]⁻.     

硼酸溶液中氯柱硼镁石的溶解及相转化动力学

对氯柱硼镁石（2MgO•2B2O3•MgCl2•14H2O）在4.5％H3BO3水溶液40 ℃的溶解及相转化过程进行了动力学研究.对不同时间取出的液相的化学分析及不同阶段分离固相的鉴定结果表明,该复盐在溶解阶段出现与前所报导不同的同步溶解，最终产物是库水硼镁石（2MgO•3B2O3•15H2O）.提出了库水硼镁石的形成条件和溶解及相转化动力学机理，利用单纯形优化法配合Runge-Kutta微分方程组数值解法对实验数据进行处理，给出了转化结晶动力学方程.     

Association Model and Its Representation of Phase Equilibria and Excess Enthalpies of Alcohol, Aniline, and Acetonitrile Mixtures

An association model is presented to describe vapor–liquid equilibria,liquid–liquid equilibria, and excess enthalpies of binary and ternary liquid solutionscontaining alcohols, aniline, and/or acetonitrile using the concepts of linearself-association of associated components and of solvation between unlike molecules.Calculated results also show that the model works well in representing thethermodynamic properties for alcohol + aniline, alcohol + acetonitrile, andalcohol + alcohol mixtures.     

Paradigms and Paradoxes: Electronegativity and Bond Energies—Living Legacies of Linus and Lee

In this paper we will discuss Pauling's classic Eq. (1) that relates bond energies, "D," and electronegativities, "x." Recast to be applicable to enthalpies of formation and reaction, we apply it to the study of hydrogenolysis reactions of dienes, diynes, and alkanes, halogenolysis reactions (with chlorine, bromine, and iodine) and metathetical reactions of organosulfur species (sulfides, sulfoxides, and sulfones). It is with great regret that this equation is found wanting.     

铅锡合金在硫酸溶液中生长阳极Pb(Ⅱ)氧化物膜的机理

用交流阻抗、开路电位衰退及线性电位扫描等方法在0.9V(vs.Hg/Hg₂SO₄)和4.5mol/LH₂SO₄溶液中,研究了铅及Pb-Sn合金电极上所生长的阳极氧化物膜.实验结果表明,阳极膜由溶解-沉淀机理控制生长,膜中微粒间为液膜,借助液膜作为离子通道可使膜中微粒发生阳极反应,锡有利于膜中PbO微粒表层阳极氧化为PbO^1+x(0相似文献   

Excess Molar Enthalpies for Isomeric Chlorobutanes with Isomeric Butanols

Abstract

Excess molar enthalpies for mixtures of each of the isomers of chlorobutane with each of the isomers of butanol were determined at the temperature 298.15 K and atmospheric pressure. Excess molar enthalpies are positive for all the mixtures. The results are discussed in terms of molecular interactions.     

Potentiometric Determination of Sibutramine Using Batch and Flow Injection Analysis

Sibutramine (SBT⁺) ion-selective electrode (ISE) was constructed using poly(vinyl chloride) matrix membrane containing sibutramine–phosphotungstate (SBT–PTA) plasticized with dioctyl phthalate. The electrode exhibits Nernstian response of 59.54 mV/ concentration decade over the concentration range 1.0 × 10^?5 to 1.0 × 10^?2 M and detection limit of 7.94 × 10^?6 M. The electrode was fully characterized in terms of its composition, response time, life span, pH, selectivity, and temperature and was then applied to the potentiometric determination of SBT in its pure bulk and pharmaceutical formulations under batch and flow injection conditions and for the in vitro testing of the dissolution profile of SBT capsules.     

HCl-NaCl-C3H8O3-H2O体系溶液热力学性质

在恒定丙三醇质量分数x=0．1的条件下，测定了无液接电池（A）和电池（B）的电动势根据电池（A）电动势确定了丙三醇和水混合溶剂中的Ag－AgCl电极的标准电极电势，讨论了HCl的迁移性质；由电池（B）测得的电动势计算了HCl在该体系中的活度系数γA，计算的结果表明，对于所讨论的体系，在溶液中总离子强度保持恒定，HCl的活度系数服从Harned规则．在溶液组成恒定时，IgγA是温度倒数1／T的线性函数，讨论了混合物中HCl的相对偏摩尔焓及介质效应．