273 K下Na2CO3-Na2SO4-Na2B4O7-H2O四元体系介稳相平衡的实验研究

采用等温蒸发法研究了四元体系Na2CO3-Na2SO4-Na2B4O7-H2O在273 K时的介稳相平衡及平衡液相的密度. 利用溶解度数据绘制了该四元体系273 K下的相图. 研究结果表明, 该四元体系有异成分复盐2Na2SO4·Na2CO3形成. 相图中有2个共饱点、5条单变量曲线和4个结晶相区. 4个结晶相区分别为盐Na2CO3·10H2O, Na2SO4·10H2O, Na2B4O7·10H2O和2Na2SO4·Na2CO3的结晶区. 复盐2Na2SO4·Na2CO3同时存在于包含Na2CO3-Na2SO4-H2O三元体系的其它四元体系或高元体系中. 在273 K介稳平衡相图中, 碳酸钠以Na2CO3·10H2O形式析出; 硫酸钠以Na2SO4·10H2O的形式析出; 硼酸钠的完整分子式为Na2B4O5(OH)4·8H2O. Na2CO3对Na2B4O7有盐析作用.     

Na2B4O7-Na2SO4-NaCl-H2O四元体系288K相平衡研究

采用等温溶解平衡法研究了四元体系Na2B4O7-Na2SO4-NaCl-H2O在288 K的相平衡关系,测定了平衡液相的溶解度及其密度。由研究结果知该四元体系为简单共饱和型,无复盐及固溶体形成。根据实验数据绘制了相应的相图。相图中有一个共饱点,三条单变曲线,三个结晶区平衡固相分别为:Na2B4O7·10H2O,Na2SO4·10H2O和NaCl。实验结果表明NaCl对Na2B4O7和Na2SO4有盐析作用,并简要讨论了实验结果。     

Li~ ,Na~ //SO_4~(2-),B_4O_7~(2-)-H_2O交互四元体系288K介稳相平衡研究

采用等温蒸发法研究了四元体系Li ,Na //SO42-,B4O72--H2O288K介稳相平衡及平衡液相物化性质(密度、电导率、折光率、粘度和pH值),测定了该四元体系288K条件下介稳平衡溶液溶解度及物化性质。根据实验数据绘制了相应的介稳相图及物化性质组成图。研究发现:该体系介稳平衡中有复盐Li2SO·4Na2SO4形成。其介稳相图中有3个共饱和点,7条单变量曲线,平衡固相为:Li2SO·4H2O,Na2SO4,Li2SO·4Na2SO4,Li2B4O7·3H2O,Na2B4O·710H2O。复盐Li2SO·4Na2SO4和一水硫酸锂(Li2SO·4H2O)有较小的结晶区,而Li2B4O7·3H2O和Na2B4O7·10H2O有较大的结晶区;该四元体系介稳平衡条件下未发现Na2SO·410H2O的结晶区。     

五元体系Li+,Na+//CO32-,So42-,B4O72-H2O 288 K介稳相平衡研究

采用等温蒸发法研究五元体系Li+,Na+//CO32-,SO42-,B4O72--H2O 288 K介稳相平衡关系,测定在288 K条件下的介稳平衡溶液中各组分的溶解度和溶液密度,根据实验数据绘制相应的介稳平衡相图及密度组成图.研究结果表明该五元体系介稳相平衡中有复盐Na3Li(SO4)2·6H2O生成,其介稳相图中有4个共饱点,9条单变量曲线,6个Li2CO3饱和的结晶区分别为LiBO2·8H2O,Na284O7·10H2O,Na2CO3·10H2O,Na2SO4,Li2O4·H2O和复盐Na3Li(SO4)2·6H2O.     

298.16 K时Na+, Mg2+//Cl-, SO42-, NO3-, H2O体系中NaCl饱和区域相平衡

采用等温溶解平衡法研究了五元体系Na+, Mg2+//Cl-, SO42-, NO3-, H2O在298.16 K下氯化钠饱和平衡体系的溶解度, 获得了相应的投影干盐图、氯图和水图. 研究结果表明, 在298.16 K下氯化钠饱和时, 该五元体系投影干盐图由8个二盐共饱和的双变面、13条三盐共饱的单变线和6个四盐共饱的零变点构成, 存在两种复盐, 8个二盐共饱双变面分别对应于NaCl+NaNO3, NaCl+Na2SO4, NaCl+MgCl2·6H2O, NaCl+MgSO4·Na2SO4·4H2O, NaCl+Mg(NO3)2·6H2O, NaCl+NaNO3·Na2SO4·2H2O, NaCl+MgSO4·7H2O 和NaCl+MgSO4·(1—6)H2O. 讨论了该相图在新疆硝酸盐矿开发利用过程中的应用.     

298.16K时Na~ ,Mg~(2 )//Cl~-,SO_4~(2-),NO_3~-,H_2O体系中NaCl饱和区域相平衡

采用等温溶解平衡法研究了五元体系Na ,Mg2 //Cl-,SO42-,NO3-,H2O在298.16K下氯化钠饱和平衡体系的溶解度,获得了相应的投影干盐图、氯图和水图.研究结果表明,在298·16K下氯化钠饱和时,该五元体系投影干盐图由8个二盐共饱和的双变面、13条三盐共饱的单变线和6个四盐共饱的零变点构成,存在两种复盐,8个二盐共饱双变面分别对应于NaCl NaNO3,NaCl Na2SO4,NaCl MgCl2·6H2O,NaCl MgSO4·Na2SO4·4H2O,NaCl Mg(NO3)2·6H2O,NaCl NaNO3·Na2SO4·2H2O,NaCl MgSO4·7H2O和NaCl MgSO4·(1~6)H2O.讨论了该相图在新疆硝酸盐矿开发利用过程中的应用.     

五元交互体系Li+,Na+,K+//CO32-,Cl--H2O在298.15K的相平衡研究

针对西藏扎布耶盐湖卤水组成,采用等温溶解平衡法研究了五元交互体系Li+,Na+,K+//CO32-,Cl--H2O于298.15K时的相平衡,并绘制了相图(空间立体图和Li2CO3饱和的投影图).结果表明,该五元体系相图含有7个结晶区、13条单变量线和4个无变量点.7个结晶区由6个单盐结晶区和1个复盐结晶区组成,分别为LiCl·H2O,NaCl,KCl,Li2CO3,K2CO3·3/2H2O,Na2CO3·10H2O和NaKCO3·6H2O,没有形成固溶体和天然碱(Na2CO3·NaHCO3·2H2O).4个无变量点标记成K1,K2,K3和K4,所对应的平衡固相盐分别是:Li2CO3+NaKCO3·6H2O+Na2CO3·10H2O+KCl,Li2CO3+NaKCO3·6H2O+K2CO3·3/2H2O+KCl,Li2CO3+NaCl+KCl+LiCl·H2O和Li2CO3+NaCl+Na2CO3·10H2O+KCl.     

四元交互体系Cd2+, Na+//Cl-, SO42——H2O 298 K时的相平衡

采用等温溶解平衡法研究了四元交互体系Cd2+, Na+//Cl-, SO2-4-H2O在298 K的相平衡关系. 研究发现, 该平衡体系存在Na2CdCl4·3H2O复盐相区, 平衡相图中有七条单变度曲线, 三个共饱和点和五个结晶相区. 其平衡固相的结晶区分别为Na2SO4、CdSO4、CdCl2·2.5H2O、Na2CdCl4·3H2O和NaCl. 该四元交互体系平衡液相的物化性质随着Cd2+浓度的增加呈现有规律的变化. 研究结果表明, 镉盐在该体系中的溶解度大, 迁移性强, 增加了土壤环境污染风险.     

273.15K下Na , K //Cl-, SO42-, NO3--H2O五元体系的相平衡研究

新疆盐湖资源丰富,冬季寒冷漫长,已有研究表明利用冬季冷能可以实现卤水浓淡分离。本文采用等温溶解平衡法针对新疆含硝酸盐卤水开发过程中涉及的Na~+,K~+//Cl~-,SO_4~(2-),NO_3~-H_2O及Na~+,K~+//Cl~-,NO_3~-H_2O体系273.15K下的相平衡关系进行了研究。通过查找文献及实验获得两个体系各盐的溶解度及溶液密度,并绘制相图。研究表明,上述四元体系的干盐相图有2个零变量点、5条单变量溶解度曲线、4个单盐结晶区分别对应于NaNO_3、NaCl、KNO_3和KCl,与该体系在298.15K下的相图相比,硝酸钾结晶区扩大很多;上述五元体系干盐相图(NaCl饱和)有2个零变量点、5条单变量溶解度曲线、4个两盐结晶区分别对应于NaCl+NaNO_3,NaCl+Na_2SO_4·10H_2O,NaCl+KNO_3,NaCl+KCl,与该体系298.15K下的相图相比,复盐钾芒硝和钠硝矾结晶区消失,芒硝结晶区扩大,相图大为简化。     

298.16K下K+,Mg2+//Cl-,NO-3-H2O体系液固相平衡

采用等温溶解平衡法研究298.16K时四元体系K+,Mg2+//Cl-,NO-3-H2O的液固相平衡关系,测定了溶解度数据,并绘制出平衡相图.研究表明,在298.16K时,该体系相图有5个单盐结晶区、6条单变量溶解度曲线和3个零变量点.5个单盐结晶区分别对应于KNO3、KCl、Mg(NO3)2·6H2O、MgCl2O和复盐KCI·MgCl2·6H2O,其中KNO3的结晶区最大,MgCl2·6H2O的结晶区最小.     

Intermolecular forces for D2, N2, O2, F2 and CO2

The intermolecular potentials for D₂, N₂, O₂, F₂ and CO₂ are determined on the basis of the second virial coeffincients, the polarizabilities parallel and perpendicular to the molecular axes, and the electric quadrupole moment. The repulsive parts of the potentials are taken from the corresponding Kihara core-potentials. Effects of the octopolar induction are taken into consideration in a unique way. The potential depends on relative orientations of the two molecules as well as the distance r between the molecular centers. This dependence is shown in graphs. A measure of the anisotropy of the potential depth is 0.72 for CO₂ 0.36 for D₂, and smaller than 0.27 for N₂ O₂ and F₂. The remarkable anisotropy for CO₂ and D₂ is due to strong electrostatic quadrupole interactions.     

Zur Trennung von H2, O2, N2, NO, CO, N2O, CO2, C2H6, C2H4, C2H2, NO2(N2O4) und Feuchtigkeit

Ohne Zusammenfassung     

Vapour-liquid equilibrium data for the systems C2H6 + N2, C2H4 + N2, C3H8 + N2, and C3H6 + N2

High pressure vapour-liquid equilibrium data for the C₂H₆ + N₂, C₂H₄ + N₂, C₃H₈ + N₂, and C₃H₆ + N₂ systems are presented. The data are obtained isothermally in the range from 200 K to 290 K. For each point of data, temperature, pressure and liquid and vapour phase mole fractions are measured.Values for the vapour phase mole fractions are calculated from the obtained pressure, temperature and liquid phase mole fractions. The calculated values are compared with the experimental results, and it is found that the average mean deviation between calculated and experimental mole fractions is less than 0.009 for the systems considered in this work.     

Ionization gauge sensitivities of N2, O2, N2O, NO, NO2, NH3, CClF3 and CH3OH

A Bayard-Alpert (BA) gauge was used to determine apparent relative sensitivites S_rel,X for O₂, N₂O, NO, NO₂, NH₃, CClF₃ and CH₃OH from gauge calibration measurements in the range 1.3×10^–1 Pap1.3·10^–3Pa. Nitrogen was used as a calibration standard.     

Spuren von Fremdgasen (H2, N2, O2, CO2) in Chlor

Ohne Zusammenfassung     

The geometry, vibrational frequencies, thermochemistry, quadrupole moments and electronic structure of C2Na2: Comparison with C2Li2, C2H2, C2F2 and C2Cl2

The electronic structure of Na₂C₂ is studied using ab initio electronic structure methods and is compared to the companion molecule Li₂C₂. Both the linear D_∞h and planar structures are minima on the ground state potential surface with the planar D_2h conformation being the lowest energy form, similar to Li₂C₂. At the CCSD(t) level the planar form is more stable that the linear by 11.2 kcal/mol as compared with 7.34 kcal/mol for Li₂C₂. Both molecules are significantly ionic. The vibrational frequencies, atomization energy at 0 K, D₀, and the standard enthalpy of formation, are calculated and compared to those of Li₂C₂ as well as HCCH, FCCF and ClCCCl. We find D₀ and to be 331.1 and 84.92 kcal/mol for Li₂C₂ and 298.3 and 93.25 kcal/mol for Na₂C₂. We calibrate these by calculating the same quantities for HCCH, FCCF and ClCCCl.     

Walsh's rules and the geometries of BH2, CH2, NH2 and OH2

Walsh's rules for first-row triatomic dihydrides are found to have significant quantitative validity.     

Infrared studies of the diatomic molecules O2, N2, NO and H2 adsorbed on Fe2O3

An infrared spectroscopic study of the diatomic molecules O₂, N₂, NO and H₂ adsorbed under different conditions on Fe₂O₃ has been performed.Complex patterns of absorption on both α-Fe₂O₃ and γ-Fe₂O₃ activated in O₂ at high temperature are assigned to vibrations of two different chemisorbed O₂ species.N₂ molecules do not interact with “oxygen rich” α-Fe₂O₃ surfaces, but give N₂O^? and N₂O₂^2? species when chemisorbed on evacuated surfaces.NO molecules give complex patterns of absorption, depending on the gas pressure. Three different types of nitrate structures can be identified, as well as NO, NO^? and cis-N₂O₂ chemisorbed species. Chemisorbed water molecules are formed by contact of H₂ with Fe₂O₃ surfaces even at room temperature.     

Conversion of NO in NO/N2, NO/O2/N2, NO/C2H4/N2 and NO/C2H4/O2/N2 Systems by Dielectric Barrier Discharge Plasmas

An experimental study on the conversion of NO in the NO/N₂, NO/O₂/N₂, NO/C₂H₄/N₂ and NO/C₂H₄/O₂/N₂ systems has been carried out using dielectric barrier discharge (DBD) plasmas at atmospheric pressure. In the NO/N₂ system, NO decomposition to N₂ and O₂ is the dominating reaction; NO conversion to NO₂ is less significant. O₂ produced from NO decomposition was detected by an on-line mass spectrometer. With the increase of NO initial concentration, the concentration of O₂ produced decreases at 298 K, but slightly increases at 523 K. In the NO/O₂/N₂ system, NO is mainly oxidized to NO₂, but NO conversion becomes very low at 523 K and over 1.6% of O₂. In the NO/C₂H₄/N₂ system, NO is reduced to N₂ with about the same NO conversion as that in the NO/N₂ system but without NO₂ formation. In the NO/C₂H₄/O₂/N₂ system, the oxidation of NO to NO₂ is dramatically promoted. At 523 K, with the increase of the energy density, NO conversion increases rapidly first, and then almost stabilizes at 93–91% of NO conversion with 61–55% of NO₂ selectivity in the energy density range of 317–550 J L⁻¹. It finally decreases gradually at high energy density. A negligible amount of N₂O is formed in the above four systems. Of the four systems studied, NO conversion and NO₂ selectivity of the NO/C₂H₄/O₂/N₂ system are the highest, and NO/O₂/C₂H₄/N₂ system has the lowest electrical energy consumption per NO molecule converted.