Chemical equilibrium constants of rare earth nitrates and tri-n-butyl phosphate complex formation

Mixed rare earth nitrates （REi（NO3）3） in the aqueous solution was mixed with tri-n-butyl phosphate （TBP, （n-C4H9O）3PO） dissolved in kerosene for the formation of their corresponding complexes （REi（NO3）3·ni（n-C4H9O）3PO） at 303 K. The effects of initial concentrations of both TBP and mixed rare earth nitrates on the equilibrium constants of their complex formations were investigated. The complexes were formed almost immediately after mixing. The simultaneous formations reached their chemical equilibria within a few minutes by shaking the mixture at 200 r/min. The chemical equilibrium constants of the complex formations were independent of the initial TBP concentrations. However, they were decreased by reducing the concentration of REi（NO3）3. All equilibrium constants of the simultaneous complex formations were less than 0.7, while the average molar ratio of TBP to REi（NO3）3 of the complexes varied between 1.0 and 1.6. The chemical equilibrium constant for the formation of La（NO3）3·（n-C4H9O）3PO was 0.09, while that of Dy（NO3）3·（n-C4H9O）3PO was 0.68. The ascending sequence of chemical equilibrium constants for the simultaneous formations was La, Ce, Pr, Nd, Eu, Y, Sm, Gd, and Dy.

Overview of the detection methods for equilibrium dissociation constant KD of drug-receptor interaction

Drug-receptor interaction plays an important role in a series of biological effects, such as cell pro- liferation, immune response, tumor metastasis, and drug delivery. Therefore, the research on drug-re- ceptor interaction is growing rapidly. The equilibrium dissociation constant （KD） is the basic parameter to evaluate the binding property of the drug-receptor. Thus, a variety of analytical methods have been established to determine the KD values, including radioligand binding assay, surface plasmon resonance method, fluorescence energy resonance transfer method, affinity chromatography, and isothermal ti- tration calorimetry. With the invention and innovation of new technology and analysis method, there is a deep exploration and comprehension about drug-receptor interaction. This review discusses the differ- ent methods of determining the KD values, and analyzes the applicability and the characteristic of each analytical method. Conclusively, the aim is to provide the guidance for researchers to utilize the most appropriate analytical tool to determine the KD values.

EQUILIBRIUM CONSTANT OF ADDUCTIVE REACTION BETWEEN BIS-(O, O′-DICYCLOHEXYLDITH-IOPHOSPHATO) NICKEL(Ⅱ) AND BENZYL-AMINE AND CRYSTAL STRUCTURE OF ADDUCTS Ni[(C_6H_(11)O)_2PS_2]_2·2NH_2CH_2C_6H_5

Ⅰ. INTRODUCTIONEsters of dithiophosphoric acid are a kind of excellent extractant for separating Co-Ni and Co-Mn. It was found that Co（Ⅱ） is easy to oxidize and to form the stable six-coordinated octahedral complex Co[（RO）2PS2] during extraction process. And it made back-extraction process very difficult. It was found that pydridine is able to cause substitute-reduction reaction with Co[（RO）2 PS2]3 and to form Co[（RO）2PS2]2·2Py. It is

A NEW METHOD FOR DETERMINATION OF EQUILIBRIUM CONSTANT OF DIMERIZATION OF PHTHALOCYANINE BY FLUORESCENCE METHOD

Phthalocyanine, because of its chemical structure similar to porphyrin and chlorophyll, easy synthesis, good stability to heat and light, has gained wide application in dyes, pigments, photoelectron materials, catalysts and photodynamic therapy, etc.

Mobile Equilibrium Method for Determining Composition and Stability Constant of Coordination Compounds of the Form M_mR_n

A new method is proposed for determining the composition and stability constant of coordination compounds of the form M m R n ; it can be used to differentiate mono and poly nuclear coordination compounds. The equation derived is lg( A i/(A max - A i) m)=n lg c′ R+lg( m·β(c M/A max ) ( m -1) ). The method is based on Bent French limited logarithm method. The demonstration of the proposed method has yielded correct results for Sc 3+ chlorophosphonazo Ⅲ system and Fe 3+ Chromazurol S system.

On an Expression of Extraction Constants without the Interfacial Equilibrium-Potential Differences for the Extraction of Univalent and Divalent Metal Picrates by Crown Ethers into 1,2-Dichloroethane and Nitrobenzene

An idea on interfacial equilibrium-potential differences () which are generated for the extraction of univalent metal picrate (MPic) and divalent ones (MPic2) by crown ethers (L) into high-polar diluents was improved. These potentials were clarified with some experimental extraction-data reported before on the M = Ag(I), Ca(II), Sr(II) and Ba(II) extraction with 18-crown-6 ether (18C6) and benzo-18C6 into 1,2-dichloroethane (DCE) and nitrobenzene (NB). Consequently, it was demonstrated that the? values from the extraction-experimentally obtained logKD,Pic ones are in agreement with or close to those calculated from charge balance equations in many cases, where the symbol, KD,Pic, denotes an individual distribution constant of Pic﹣ into the DCE or NB phase. Also, it was experimentally shown that extraction constants based on the overall extraction equilibria do not virtually contain the? terms in their functional expressions.

浮选固液系统的热力学理论及应用

浮选是发生在固液界面的物理化学行为,涉及多种物质组分之间的相互作用,是浮选理论研究的难题之一。同时,多种浮选药剂联合使用,提高矿物的浮选效果,是提高难处理矿产资源高效利用的有效手段。但对浮选固液复杂系统的研究极其困难,至今没有形成系统的理论,组合药剂提高浮选效果的物理机制也还没有获得统一的认识,这都限制了浮选理论的发展和浮选技术的进步。基于热力学基本方程,研究了浮选过程中药剂在矿物表面吸附的熵变和吉布斯自由能变化,构建了各种物质组分相互作用的热力学平衡方程组,提出了反映浮选药剂在矿物表面吸附能力的吸附平衡常数。应用浮选热力学平衡方程组,揭示浮选中各种矿物表面同质化效应的物理本质,推导出了浮选溶度积理论、双电层理论、吸附理论的数学表达式。建立了通过增加矿物表面吸附浮选药剂种类,提高浮选药剂的吸附熵变,减少吉布斯自由能变化,提高浮选药剂吸附的效率和稳定性,从而提高难处理矿物的浮选效果的高熵浮选理论和技术方法。

一类含常数项的混沌系统在未知参数下的同步

研究了一个新的含有常数项的混沌系统在参数未知情况下的修正函数投影同步问题。对新的含有常数项的混沌系统从平衡点的稳定性、耗散性、poincare映射、功率谱及初值敏感性5个方面进行了特性分析。基于修正函数投影同步方法,设计了有效的控制输入及参数自适应律,根据Lyapunov函数稳定性定理从理论上证明修正函数投影同步误差系统在原点的渐近稳定性,从而实现了新混沌系统的修正函数投影同步控制。数值模拟仿真证明了同步方法的正确性,该同步方法可以应用于混沌保密通信的研究中。

乙烯基醚系列产品合成过程的热力学研究

乙烯基醚是一类重要的聚合单体,但针对其合成过程的系统热力学分析尚未见报道。分别采用Benson法、Joback法等方法,以经典热力学公式为基础,计算了乙炔与不同醇(甲醇、乙醇、丁醇、异丁醇以及叔丁醇)合成对应乙烯基醚类化合物(乙烯基甲醚、乙烯基乙醚、乙烯基丁醚、乙烯基异丁醚以及乙烯基叔丁醚)的热力学参数,包括在反应温度为283~363 K下的焓变(△_(r) H^(θ))、熵变(△_(r) S^(θ))、吉布斯自由能(△_(r) G^(θ))和反应平衡常数(K)。系统分析和总结了不同结构的醇与乙炔发生亲核加成反应过程的难易程度,以及热力学反应参数的变化规律。结果表明,所有反应均为强放热反应且均可自发进行,反应温度越低反应进行得越彻底。即使在近室温(283 K)条件下,乙烯基醚类化合物仍可顺利合成,且反应温度越低,安全性越高。本研究结果可为乙烯基醚工业化生产提供理论指导。

EQUILIBRIUM OF Mg-S IN Ni MELTS

The equilibrium of Mg-S in Ni melt was studied by the method of vapour equilibrium in a sealed chamber.At 1530℃ the equilibrium constant of the reaction MgS_(s)=Mg_(Ni)+S_(Ni)and the activity interaction coefficient were determined as K_(MgS)=6.76×10^(-5)and e_S^(Mg)=-9.1.

多相体系的酸碱解离平衡:气相的影响

酸碱平衡是化学教学中十分重要的内容,而在目前的教学中仅仅描述了均相溶液中的酸碱解离与pH缓冲问题,并未描述多相体系中气相成分对体系酸碱解离与pH缓冲的影响。针对该问题,本文以典型的气溶胶多相体系为例,通过对多相缓冲理论和有效解离常数pK_(a)^(*)的分析,讨论了多相体系中组分挥发性和吸湿性对体系酸碱平衡的影响,进而开拓学生思维,并为多相体系酸碱平衡的教学提供新范例。

Thermal Analysis of Thermophysical Data for Equilibrium Pure Fluids

The thermal analysis of precise thermophysical data for pure fluids from electronic databases is developed to investigate the molecular interaction mechanisms and parameters and the structural features of heterogeneities in fluids. The method is based on the series expansion of thermophysical values by powers of the monomer fraction density. Unlike the virial expansion by powers of the total density, the series expansion terms in this method directly reflect properties of the corresponding cluster fractions. The internal energy had been selected among thermophysical properties as the most informative for this method. The thermal analysis of its series expansion coefficients permits to estimate the temperature dependence of the pair bond parameters, the clusters’ bond energies and equilibrium constants, the structural transitions between dominating isomers of clusters. The application of method to different pure fluids, including noble and molecular gases with van der Waals and polar molecular interactions, brings unknown clusters’ characteristics for the fluids under investigation. The thermal analysis of the ordinary and heavy Water vapors points on no trivial isotopic effects. The unpredictable growth of the pair bond energy with temperature in Alkanes points on existence in hydrocarbons of some unknown molecular interaction forces in addition to dispersion forces.

Equilibrium Thermal Physics of Noble Gases

The aim of this research is to apply the author’s original computer aided analysis of thermophysical data for pure fluids to noble gases to investigate the unknown aspects in their equilibrium thermal physics. The methodology of the analysis is based on the potential energy density series expansion by the monomer fraction density. To discover the important details and particular features of pair atomic interactions in noble gases, the preprocessed and generalized experimental data have been taken from the US National Institute of Standards and Technology (NIST) online database. In this work the temperature range for analysis of the dimers’ bonding parameters is extended as compared to previous author’s works due to accounting for the specific temperature dependence of the repulsions’ contribution to the potential energy. The found temperature dependences of the pair interaction bond energies signal about the hindered rotation of atoms in dimers near the triple point due to the lack of rotational symmetry of their electronic outer shells. The discovered mutually correlated anomalous temperature dependences of the pair bond energy and the constant volume heat capacity in gaseous Helium require a special investigation of this remarkable phenomenon.

Geometrical structures, vibrational frequencies, force constants and dissociation energies of isotopic water molecules (H_2O, HDO, D_2O, HTO, DTO, and T_2O) under dipole electric field

The dissociation limits of isotopic water molecules are derived for the ground state. The equilibrium geometries, the vibrational frequencies, the force constants and the dissociation energies for the ground states of all isotopic water molecules under the dipole electric fields from -0.05 a.u. to 0.05 a.u. are calculated using B3P86/6-311＋＋G（3df,3pf）. The results show that when the dipole electric fields change from -0.05 a.u. to 0.05 a.u., the bond length of H-O increases whereas the bond angle of H-O H decreases because of the charge transfer induced by the applied dipole electric field. The vibrational frequencies and the force constants of isotopic water molecules change under the influence of the strong external torque. The dissociation energies increase when the dipole electric fields change from -0.05 a.u. to 0.05 a.u. and the increased dissociation energies are in the order of H2O, HDO, HTO, D2O, DTO, and T2O under the same external electric fields.

固液相平衡计算研究进展

围绕固液相平衡计算,综述了活度系数法、经验模型法和状态方程法的研究进展和应用。概括和分析了活度系数模型(Pitzer、ELECNRTL、Wilson、NRTL、UNIQUAC、正规溶液理论)、经验模型(λh、Apelblat、Jouyban-Acree)和状态方程模型(PR、SRK、Martin-Hou),并介绍了模型的适用范围及优缺点。固液相平衡计算模型对化工固液分离过程中的理论研究和工业应用具有重要意义。

Measurement and model of density,viscosity,and hydrogen sulfide solubility in ferric chloride/trioctylmethylammonium chloride ionic liquid

The density and viscosity of ferric chloride/trioctylmethylammonium chloride ionic liquid(rFeCl_(3)/[A336]Cl)with different molar ratios(r=0.1-0.8)of FeCl_(3) to[A336]Cl were measured at temperatures from 313.15 to 358.15 K and atmospheric pressure.The density and viscosity data were fitted by the relevant temperature variation equations,respectively.The variation of density and viscosity with temperature and r was obtained.The solubility of rFeCl_(3)/[A336]Cl to H_2S was measured at temperatures from 318.15 to 348.15 K and pressures from 0 to 150 kPa.The effects of temperature,pressure,and r on the solubility of H_(2)S were discussed.The reaction equilibrium thermodynamic model(RETM)was used to fit the H_(2)S solubility data,and the average relative error was less than 1.3%,indicating that the model can relate the solubility data well.And Henry's constant and chemical reaction equilibrium constant were obtained by the RETM fitting.The relationships of Henry's constant and chemical reaction equilibrium constant with temperature and r were analyzed.

氨基甲酸铵分解平衡实验教学研究

“氨基甲酸铵分解平衡实验”是物理化学实验中关于化学平衡的一个经典实验,该实验有利于学生加深对化学平衡的理解、掌握物理法测定化学平衡常数及巩固化学平衡常数与热力学函数之间的关系。为了提高实验教学质量,改善实验教学效果,对该实验中学生疑惑及易出错的地方,给出了解释及优化方法。采用优化的实验方案用时更少,测得的实验结果准确度高,有效提高了教学效果。

Density of Vacuum-Like Plasma and Hubble Constant

The model in which expansion of the Universe leads to a generation of non-equilibrium vacuum-like electron-positron plasma is proposed and researched. The formulas that relate the Hubble’s constant with the concentration of plasma particles and the cosmological constant are obtained. The collective properties of vacuum-like plasma are investigated. It is shown, that the coefficient of a two-photon annihilation in such plasma is nine times less than for the free particles. A simple formula for dark energy density as a function of electron mass and charge is obtained. It was demonstrated that acceleration of plasma’s chemical potential fluctuations flow proportional of dark energy density.

矿物浮选吸附平衡模型构建与应用:精准解析矿物表面离子/药剂特征吸附

矿物浮选吸附平衡模型是准确描述矿物浮选过程中所涉及的矿物表面离子/药剂吸附平衡的数学模型,首次实现了矿物表面位点与浮选药剂吸附作用亲和性的量化解析。传统浮选理论对矿物表面作用位点缺乏科学描述,难以阐明浮选药剂的吸附作用能力及平衡状态,新浮选药剂体系开发多以“试错法”“复配法”等经验性方法为主。药剂选择性吸附作为浮选作业的核心机制,若不能准确预测其在各矿物表面的吸附行为,将严重限制浮选工艺智能化控制的发展。本文详细论述了矿物浮选吸附平衡模型的构建原理,以赤铁矿-石英和一水硬铝石-高岭石两个浮选体系为例,通过对少量实验数据的拟合计算,解析出矿物表面活性位点密度Ns、加/去质子反应常数K_(t1)/K_(t2)、药剂吸附常数Kf等矿物浮选特征常数。将解析的矿物浮选特征常数代入到平衡模型中,预测出各条件下矿物表面电性、离子及浮选药剂的吸附量,通过零电点、实验及测试等方法验证了可靠性,形成了矿物浮选过程预测系统的内核算法。该算法对各条件下每种矿物药剂吸附的初步准确预测,可在一定程度上反映其可浮性趋势,有助于缩短浮选工艺开发周期,对矿物表面药剂吸附机理研究、浮选药剂分子设计、浮选工艺流程优化及智能控制等具有重要意义。

非理想稀溶液中溶质化学反应达平衡时化学反应等温式的探讨

物理化学中化学平衡一节关于非理想稀溶液中溶质化学反应,当反应达到平衡时的化学反应等温式中,在讨论标准平衡常数时并未提及所对应的标准态的组成表示,因此很多初学者会忽略组成表示的选取而直接计算标准平衡常数导致计算结果产生偏差,所以建议在反应达平衡时化学反应等温式中的与的公式中分别用下角标标注出相应的组成的表示,以便使初学者更容易的记忆和使用公式。