气液色谱法研究双-(O,0′-二正辛基二硫代磷酸酯)合镍(Ⅱ)与酮类加合反应的热力学性质

二烷基二硫代磷酸酯及其过渡金属配合物具有强杀菌性能及抑制酶水解作用,可以用作石油添加剂和高聚物防老剂,又是一类优良的萃取剂,用于钴镍、钴锰等的萃取分离^[1-2]。二硫代磷酸酯的金属盐与含氮、含氧的有机碱形成的加合物在液-液萃取中起着重要作用^[3],因此这类配物合的加合作用受到了广泛的注意。     

Vapor–liquid equilibria and excess properties for methyl tert-butyl ether (MTBE) containing binary systems

Methyl tert-butyl ether (MTBE) is recently widely used in the chemical and petrochemical industry as a non-polluting octane booster for gasoline and as an organic solvent. The isobaric or isothermal vapor–liquid equilibria (VLE) were determined directly for MTBE+C₁–C₄ alcohols. The excess enthalpy (H^E) for butane+MTBE or isobutene+MTBE and excess volume (V^E) for MTBE+C₃–C₄ alcohols were also determined. Besides, the infinite dilute activity coefficient, partial molar excess enthalpies and volumes at infinite dilution (γ^∞, H^E,∞, V^E,∞) were calculated from measured data. Each experimental data were correlated with various g^E models or empirical polynomial.     

RbCl和CsCl水溶液结构的X射线散射及经验势结构精修模拟

采用X射线散射法研究了RbCl和CsCl水溶液的结构,利用基于经验势的结构精修(EPSR)方法获得了溶液中的水合Cl^-、Rb⁺、Cs⁺、离子缔合及本体水的对径向分布函数、配位数分布及空间密度分布(3D结构)等结构信息。在水溶液中,Cl^-具有相对稳定的6水合结构,其水合距离为0.321 nm,外加阳离子对其水合作用的影响不明显。7.3 ± 1.4个水分子与Rb⁺水合,其特征水合距离为0.297 nm,8.4 ± 1.6个水分子与Cs⁺水合其水合距离为0.312 nm。Cs⁺不具有第二水合层,而Rb⁺表现出了更强的水合能力,具有较明显的第二水合层。Cl^-、Rb⁺及Cs⁺常被认为是“结构破坏”型离子。从微观角度来看这种所谓的“结构破坏”主要体现在破坏了本体水分子的第二水合层保持四面体构型的趋势。RbCl和CsCl水溶液中部分存在着Rb-Cl和Cs-Cl直接接触离子对,在1.0 mol·dm^-3的溶液中Rb-Cl及Cs-Cl的特征距离分别为0.324和0.336 nm,溶剂分割离子对的距离则都在0.6 nm左右。相对于Cs⁺,Rb⁺与Cl^-离子之间表现出了更强的缔合能力。     

四苯基卟啉及其衍生物的结构与性质研究(Ⅳ)——二质子四苯基卟啉及其衍生物的光谱、pKa与取代基常数间的线性关系

以HMO法剖析了二质子四苯基卟啉(H₂TPP²⁺)及其衍生物的紫外-可见光谱,确定了四苯基卟啉(TPP)和H₂TPP²⁺及其衍生物的λ_max、pK_a与取代基常数σ间的线性关系。     

Alumina Solubility in Na3AlF6-K3AlF6-AlF3 Molten Salt System Prospective for Aluminum Electrolysis at Lower Temperature

The alumina solubility in the title system within the composition range of KR{m(K₃AlF₆)/[m(K₃AlF₆)+ m(Na₃AlF₆)]} 10%―50%, a ternary Na₃AlF₆-K₃AlF₆-AlF₃ molten system with 23%―29%(mass fraction) AlF₃ was investigated by measuring the mass loss of a rotating sintered corundum disc. And the following empirical equation was derived when superheat degree was no more than 60 ℃: w(Al₂O₃)_sat=A×(T/1000)^B, where A= –1.85774+ 26.754234w(AlF₃)^–0.3683–0.00783KR^2.363+0.010266KR^2.3048+0.7902w(AlF₃)^0.00652, B=112.4625–53.2567w(AlF₃)^0.4236+ 5.1079w(AlF₃)^0.9241+0.01542w(AlF₃)^1.3540. Considering both higher alumina solubility and not too high superheat degree are required, alumina solubility of different compositions at not the same temperature but the same superheat degree was studied, which will be more industrial helpful for selecting prospective compositions. The results show that the composition deserved to be further tested in lower temperature cells is 10%―30% KR and 23%―26%(mass fraction) AlF₃.     

十二钨酸络钴酸钾氧化肼、不对称二甲肼和羟胺的动力学和机理

本文研究了十二钨酸络钴酸钾(K₅Co(Ⅲ)W₁₂O₄₀,简记为Co(Ⅲ)WO)氧化电位和pH的关系,Co(Ⅲ)WO在最大吸收处(388nm)吸光度和浓度间的关系。用分光光度法研究了Co(Ⅲ)WO在HAc-NaAc缓冲体系中氧化硫酸肼、不对称盐酸二甲肼、硫酸羟胺的动力学,给出了相应的表观活化能、活化熵等动力学参数,讨论了通过氩键传递电子的可能性。     

Metastable Phase Equilibrium in the Reciprocal Quaternary System LiCl+MgCl2+Li2SO4+MgSO4+H2O at 348.15 K and 0.1 MPa

The metastable solubilities and the physicochemical properties including density and pH of the reciprocal quaternary system(LiCl+MgCl₂+Li₂SO₄+MgSO₄+H₂O) at 348.15 K and 0.1 MPa were determined using the isothermal evaporation method. The dry-salt diagram and water-phase diagram were plotted based on the experimental data. There are five invariant points, eleven univariant curves, and seven crystallization zones corresponding to hexahydrite, tetrahydrite, kieserite, bischofite, lithium sulfate monohydrate, lithium chloride monohydrate and lithium carnallite. Comparison between the stable and metastable diagrams at 348.15 K indicates that the metastable phenomenon of magnesium sulfate is obvious, and the crystallization regions of hexahydrite and tetrahydrite disappear in the stable phase diagram. A comparison of the metastable dry-salt phase diagrams at 308.15, 323.15 and 348.15 K shows that with the increasing of temperature the epsomite crystallization zone disappears from the dry-salt phase diagram of 303.15 K, and a new kieserite crystallization zone is presented at 348.15 K. The density and pH in the metastable equilibrium solution present regular change with the increasing of Jänecke index J(2Li⁺), and the calculated densities using the empirical equation agree well with the experimental values.     

Infrared spectra of heterocumulenes—VII: Correlations of infrared gruop wavenumbers and integrated absorption intensities in some heterocumulenes with substituent constants

A statistical evaluation of the empirical linear relations of the ν_as(X=Y=Z) integrated absorption intensities (A) in forty various heterocumulenes with substituent constants σ and σ⁺ has been carried out. The correlations of log A with substituent constants show that the positive sign of the slopes and ⁺ has been observed, suggesting that with all heterocumulenes studied the structure of the X=Y=Z group with cumulative bonds is dominant.     

电解质在混合溶剂中的活度系数及溶剂化数的研究——KClO4-CH3OH-非电解质体系

本文测定了KClO₄在甲醇-苯,甲醇-甲苯,甲醇-四氯化碳及甲醇-环己烷四个混合溶剂中的溶解度。使用A.D'Aprano[4]和C.W.Davies[2],报告的KClO₄及KNO₃在甲醇中的缔合常数,计算得“自由离子”浓度。盐的介质效应活度系数f_MX以S_o/S_m或S_o±、D_m±的表示值趋近相等,与非电解质的摩尔分数X₍Ne的关系符合经验公式:1gf_MX=kX_Ne,这里S_o和S_m分别是盐在甲醇和混合溶剂中的溶解度;脚注(±)标识“自由离子”;k为常数。电解质的溶剂化数公式:n₊+n_-=-21gf_MX/1gφ_ρ,对KClO₄在这些混合溶剂中的情况并不适用,这里n₊+n_-是正、负离子溶剂化数之和;φ_p是甲醇在混合溶剂中的体积分数。这个结果表明ClO₄^-的溶剂化层不是完全由甲醇分子所形成,非电解质也影响着ClO₄^-在这些溶剂中的溶剂化层。KNO₃的实验数据,溶解度公式和溶剂化数公式是引自李芝芬、黄子卿、刘瑞麟以前的论文。     

Substantial velocity dependence of rotationally inelastic collision cross sections in Li2—Xe

A Doppler-based velocity selection technique has been used to measure the relative velocity dependence of the cross sections σ_ji,Δ(ν_r) for rotationally inelastic collisions from level j_i to j_i + Δν₁ = 8,22,42) in ⁷Li^*₂ A ¹Σ⁺_u)—Xe. The σ_jν^±2(ν_r) are strongly attenuated at a smaller ν_r by “torque averaging” due to molecular rotation; in contrast, for large |Δ|, σ_jiΔ = ν_r⁻ⁿ (1 n 2). An empirical intermolecular potential which reproduces these types of behavior for 3-D classical trajectories is exhibited.     

Simplified models for anharmonic numbers and densities of vibrational states. I. Application to NO2 and H3

Numbers and densities of vibrational states of non-rotating polyatomic molecules are calculated by a simplified model which accounts for Morse anharmonicities of stretching and for generalized empirical stretch-bend couplings of bending modes. At energies above the dissociation limit, adiabatic channel maxima restrict the molecular phase space. The model is applied to the NO₂( 2A₁), NO₂(Ã ²B₂), and H₃⁺ systems for which satisfactory agreement with the available experimental or calculational results is obtained.     

The solvation of Li and Na in acetonitrile from ab initio-derived many-body ion–solvent potentials

Several Li⁺- and Na⁺-acetonitrile models were derived from ab initio calculations at the counterpoise-corrected MP2/TZV++(d,p) level for distorted ion-(MeCN)_n clusters with n=1, 4 and 6. Two different many-body ion-acetonitrile models were constructed: an effective three-body potential for use with the six-site effective pair model of Böhm et al., and an effective polarizable many-body model. The polarizable acetonitrile model used in the latter model is a new empirical model which was also derived in the present paper. Mainly for comparative purposes, two ion-acetonitrile pair potentials were also constructed from the ab initio cluster calculations: one pure pair potential and one effective pair potential. Using all these potential models, MD simulations in the NPT ensemble were performed for the pure acetonitrile liquid and for Li⁺(MeCN) and Na⁺(MeCN) solutions with 1 ion in 512 solvent molecules and with a simulation time of at least 120 ps per system. Thermodynamic properties, solvation-shell structure and the self-diffusion coefficient of the ions and of the solvent molecules were calculated and compared between the different models and with experimental data, where available. The Li⁺ ion is found to be four-coordinated when the new many-body potentials are used, in contrast to the six-coordinated structure obtained for the pure pair and effective pair potentials. The coordination number of Na⁺ is close to six for all the models derived here, although the coordination number becomes slightly smaller with the many-body potentials. For both ions, the solvent molecules in the first shell point their nitrogen ends towards the cation, while in the second shell the opposite orientation is the most common.     

Synthesis of chelating trimethylsiloxy diisonitrile ligands and their rhodium(1) complexes. Crystal and molecular structure of [Rh(t-BuDiNC)2]BPh4·1.5CH3CN (DiNC = chelating bidentate isonitrile ligand)

An X-ray crystallographic study, the first of a complex containing a chelating bidentate isonitrile (DiNC) ligand, reveals that [Rh(t-BuDiNC)₂]BPh₄·1.5CH₃CN crystallizes as a “slipped-stacked” face-to-face dimer of two approximately planar [Rh(t-BuDiNC)₂]⁺ cations with a Rh-Rh distance of 3.384 Å, and an angle of 22.7° between the stacking axis and the Rh---Rh vector. The syntheses of two new bidentate isonitrile ligands, SiNC-2 and SiNC-3 are also described. These ligands contain bulky trimethylsiloxy groups ortho to each isonitrile group and differ only in that the SiNC-3 ligand contains an additional CH₂ unit in its backbone. Each reacts with [Rh(COD)Cl]₂ to afford, after metathesis with KPF₆, a complex of the empirical formula [Rh(SiNC-n)₂]PF₆. Spectroscopic results suggest the SiNC-2 complex is dinuclear, with four SiNC-2 ligands bridging the two rhodium atoms. The SiNC-3 complex is mononuclear, but unlike most other mononuclear [Rh(CNR)₄]⁺ complexes, shows no tendency to self-associate in solution. The different structures of these two complexes and the solution behavior of the SiNC-3 complex are attributed to the bulkiness of the trimethylsiloxy groups.     

Silica-supported alkylidene complexes: their preparation, characterization and reactivity, especially towards olefins

When silica is employed as a bidentate ligand to bis(alkyl) complexes of the early first-row transition metals, rare terminal alkylidene fragments are readily formed and stabilized. These materials have the empirical formula (SiO)₂M=CHEMe₃, where M is Ti, V, or Cr and E is C or Si, incorporating two covalent interactions with oxygens of the silica surface which serve to immobilize the grafted complexes. The silica-supported alkylidene complexes undergo several typical reactions, including electrophilic cleavage with H⁺ and Br₂, metathetical exchange with acetone and styrene, and addition of a silane. Reaction with ethylene leads to oligomerization/polymerization, for which the material with M=Cr is particularly effective. The mechanism of initiation of polymerization, as well as the influence of the silica support (fumed versus precipitated) on the composition of the active sites, is discussed.     

Ion-exchange properties of hypercrosslinked polystyrene impregnated with methyl orange

A novel bipolar stationary phase (HCPS–MO) was prepared by impregnation of hypercrosslinked polystyrene (HCPS) with methyl orange (MO; 4-dimethylamino-4′-sulfoazobenzene) and its ion-exchange properties were studied. Simultaneous separation of cations and anions on HCPS–MO is possible, although it behaves preferentially as a cation-exchanger. Unusual selectivity of HCPS-MO for alkali and alkaline-earth metal cations: Na⁺+K⁺+4⁺+ and Mg²⁺2+2+2+ was observed. The effect of temperature on retention of alkali and alkaline-earth metal cations was studied. Separation of Na⁺, K⁺, Rb⁺, NH₄⁺, Cs⁺, Mg²⁺ and Ca²⁺ on HCPS–MO with diluted cerium(III) nitrate solution as an eluent in single run is presented.     

Separation and detection of common mono- and divalent cations by ion chromatography with an ODS column and conductivity/UV detection

The retention and detection behavior of common mono- and divalent cations (M⁺, alkali metal (Li⁺, Na⁺, K⁺, Rb⁺, Cs⁺) and ammonium ions (NH₄⁺); M²⁺, alkaline earth metal ions (Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺) was examined using an ODS column (150×4.6 mm I.D.) and conductivity (CD)/UV detection. The results obtained were as follows: (1) for M⁺, the mobile phase, 0.1 mM sodium dodecyl sulphate (SDS)+10 mM HNO₃ and indirect CD detection were effective. (2) Addition of Ce(III) in the mobile phase accelerated the elution of both M⁺ and M²⁺. The separation of above 10 cations on an ODS column was achieved for the first time without any coelution of cations and disturbance by system peak. Addition of higher SDS resulted in good separation of M⁺ and M²⁺ with longer retention times. CD detection was possible for M⁺ and M²⁺ and UV detection for M²⁺. (3) For M²⁺, the mobile phase, 0.8 mM Ce(III)+0.1 mM SDS+1 mM HNO₃ and indirect UV detection were effective. The IC methods were applied to real samples.     

Ca2+,Th4+和抗磁稀土离子与2,3-二羟基-对-二甲苯胺四乙酸的成络作用

本文用¹H NMR和UV VIS光谱技术研究了DPTA与Ca⁺²、Th⁴⁺和抗磁稀土离子Ia³⁺、Lu³⁺、Y³⁺、Sc³⁺的成络作用,发现配体与抗磁稀土离子为慢交换体系,而与Ca²⁺为快交换体系。确定了络合物的组成,Th⁴⁺与试剂生成1:2络合物,Ca²⁺、La³⁺、Lu³⁺、Y³⁺、Sc³⁺主要生成1:1络合物。络合物组成与溶液pH有关。     

稀土离子跨人血红细胞膜的荧光法研究

采用Fura-2荧光浓度指示剂对红细胞的稀土跨膜作用进行了系列研究.结果表明,稀土离子不能通过完整的红细胞膜进入细胞内.通过与离子载体实验相对照,发现细胞ATP耗竭后,低浓度的稀土离子(5×10^-6mol/L)不能跨膜进入ATP-耗竭红细胞.KCl去极化及加入电压依赖性钙通道刺激剂Bay-K8644对稀土离子的跨膜也没有促进作用.在Ca²⁺内流正常的情况下,低浓度稀土离子(5×10^-6mol/L)对钙离子内流无影响.增大稀土离子浓度到5×10^-4mol/L,用显微镜观察此时红细胞已开始溶血.在模拟胞内离子组分的缓冲液中(pH=7.05),比较了La³⁺,Eu³⁺和Ca²⁺对Fura-2的敏感程度.此条件下Fura-2对La³⁺和Eu³⁺的检测限分别为10-12和10-14mol/L,对Ca²⁺的检测限为10-8mol/L,并测得Fura-2-La³⁺(Eu³⁺)的络合比为1∶1,表观离解常数为1.7×10^-12和4.95×10^-14mol/L,表明用此法检测稀土离子跨膜行为相当灵敏有效.     

NH3R++NHR2(R=H,CH3)体系质子传递反应的从头算研究

用从头计算法在HF/6-31G^*基组水平上研究了NH₄⁺+NH₃→NH₃+NH₄⁺,NH₄⁺+NH₂CH₃→NH₃+NH₃CH₃⁺,NH₄⁺+NH(CH₃)₂→NH₃+NH₂(CH₃)₂⁺以及NH₃CH₃⁺+NH₂CH₃→NH₂CH₃+NH₃CH₃⁺等4个体系的质子传递反应的机理.结果表明:(1)上述质子传递反应均具有双阱型的势能面,质子沿N(1)、N(2)连线直接传递;(2)质子受体分子中的甲基对质子传递起促进作用,而质子给体离子中的甲基则阻碍质子的传递。     

酸性溶液中Fe2+ /Fe3+相互转换对电极还原行为的影响

采用线性扫描伏安法和循环伏安法研究了含有Cl^-、SO₄^2-的酸性溶液中Fe²⁺/Fe³⁺相互转换对电极反应和Fe³⁺还原过程的影响. 结果表明: [Fe]_T=1 mol·L-1条件下,溶液中Fe³⁺/Fe²⁺的还原析出过程经过两个阶段：(1) E=0.35 V左右Fe³⁺还原成Fe²⁺过程; (2) E=-0.3 V之后H+的还原同时Fe²⁺离子与OH^-相结合生产Fe(OH)₂; Fe³⁺/Fe²⁺的相互转化主要影响Fe³⁺的第一还原阶段的还原峰电流和峰电位. |ipa/ipc|值随c(Fe³⁺ )/c(Fe²⁺ )增大而增大,且扫描速度慢时影响大,扫描速度快时影响小; 0.50 mol·L^-1 Fe²⁺+0.50 mol·L^-1 Fe³⁺时,随扫描速率的变化|ipa/ipc|值变化最小(|i_pa/i_pc|≈1.20). 同时,c(Fe³⁺ )/c(Fe²⁺ )也影响平衡电位,平衡电位随c(Fe³⁺ )/c(Fe²⁺ )增大而正移,电位从E₁=0.501 V升至E₅=0.565 V.