Ion-pair formation in aqueous solutions of silver nitrate: A Raman and infrared spectral study

A detailed study of the Raman and infrared spectral line shapes and line parameters of aqueous solutions (both H₂O and D₂O) of AgNO₃ is interpreted in terms of an equilibrium between “free” ions and the ion pair Ag⁺NO ₃ ^? . An association constant of 0.1M ^?1 was obtained from both the 717 cm^?1 and 1047 cm^?1 line intensities. Spectral features suggest a significant degree of covalence in the interaction. A C_s(σ_V) model with Ag⁺ above the plane of NO ₃ ^? is consistent with the data.     

大孔吸附树脂对邻甲酚的吸附行为研究

研究了大孔吸附树脂NDA—909吸附水溶液中邻甲酚的热力学特征，并与Amberlite XAD—4树脂进行了比较．通过吸附动力学实验，初步探讨了初始温度对吸附过程的影响。结果表明，NDA—909对邻甲酚的吸附符合Freundlich经验公式，表现为放热的物理吸附过程．此外吸附速率受颗粒内扩散和其它类型扩散的共同控制。     

高效液相色谱手性流动相添加剂法拆分酪氨酸甲酯对映体

分别将β-环糊精、羟丙基-β-环糊精作为手性流动相添加剂，研究了酪氨酸甲酯对映体在反相HPLC系统中的拆分，考察了流动相种类、pH和手性流动相添加剂浓度对手性拆分的影响，建立了β-环糊精手性流动相添加剂法拆分酪氨酸甲酯对映体的方法。     

Fragmentation processes of methylbutyl trifluoroacetates studied by tandem quadrupole mass spectrometry and isotope labeling

The fragmentation patterns of 3-methyl-2-butyl trifluoroacetate and 2-methyl-2-butyl trifluoroacetate were investigated by GC/MS/MS, with electron impact and collision-induced dissociation, on regular and isotope-labeled (deuterium and ¹⁸O) esters. The atoms found in various fragments could be traced back to specific positions in the parent molecules. In this way, molecular rearrangements potentially occurring during the formation of esters by trifluoroacetolysis of 3-methyl-2-butyl p-toluenesulfonate or trifluoroacetic acid addition to various 2-methylbutenes could be shown. Rearrangements also occurred during the fragmentation, particularly during the expulsion of the small fragments CO, C₂H₄ and F₂CO. For the decompositions of oxygen-containing ions these rearrangements were highly specific. By contrast, alkyl cations lead to fragments that are fully scrambled (statistical label distribution). Alkene radical cations ([C_nH_2n]^{+ ˙}) fragment to daughter ions that are extensively, but less than statistically scrambled. Hydrogen scrambling may also occur in fluoroalkyl cation fragments.     

Dissociation Constants and Chelate Stability Constants of Some Dihalogenated 8-Hydroxyquinaldines

The acid dissociation constants of dihalogenated 8-hydroxyquinaldines and the stability constants of their chelates with Zn[II], Ni[II], Co[II], Pb[II], Cd[II], Mn[II], and Mg[II] have been determined. The Calvin-Bjerrum potentiometric titration technique was used in studying the behavior of these substances. The order of decreasing stability of the metal chelates Zn, Nc>Co>Pb>Cd>Mn>Mg is similar to the stability sequence generally obtained for divalent metals, and the order of decreasing stability of dihalogenated 8-hydroxyquinaldines to form the metal chelates with metal ions is I>Br>Cl. Spot test reactions of dihalogenated 8-hydroxyquinaldines and 8-hydroxyquinolines with the metal ions also have been investigated.     

Iodide Ion-Selective Electrode and Its Application to the Determination of Organic Compounds

The mixture of silver iodide and ferrocene is used to prepare the membrane of iodide ion-selective electrode. The interference of sulfide can be reduced by the addition of cupric ion in the test solution. Ethylene glycol is determined by potentiometric titration using iodine ion-selective electrode as an indicator electrode.     

Waugh-型镍钼杂多酸的量子化学计算

采用半经验INDO法，完成了Waugh-型镍钼杂多酸（NH44）6〔NIMO9O32〕·6H2O的量子化学计算，得到146个成键轨道和78个反键轨道，轨道能级，电荷和键序等数据。通过对这些数据的分析，表明杂多酸分子中端氧和Ni都可能为化学活性中心，各原子轨道在分子轨道中都占有一定比例，其HOMO和LUMO能级皆为负值，其体系具有进一步接受电子的能力。这些结论与实验事实一致。     

Chlorine nitrate photolysis by a new technique: very low pressure photolysis

Very low pressure photolysis (VLPØ) of chlorine nitrate was performed in a quartz Knudsen cell. The light source was a 2500 W high-pressure xenon lamp, and a modulated molecular-beam mass spectrometer was used to monitor the concentration of ClONO₂ and photolysis products. Because of the low pressures used (? 10^?3 torr) and the short residence time in the cell (≈1 s), secondary reactions were unimportant and the primary products could be directly identified. The primary photolysis products (λ ≈ 2700 Å) are atomic chlorine and NO₃ free radical. Chlorine atoms were identified both by the appearance of Cl₂ (wall recombination product; the walls were not poisoned) and by HCl produced when C₂H₆ was added to the cell. Nitrate free radical was directly identified as a mass peak at m/e = 62, as well as by chemical titration with nitric oxide: NO₃ + NO → 2NO₂. It was verified by direct tests that the peak at m/e = 62 did not arise from possible HNO₃ contamination or from N₂O₅, a possible secondary product. This titration reaction was used to measure quantitatively a lower limit to the primary quantum yield, φ ? 0.5 ± 0.3. This represents a lower limit because of the unknown extent of the secondary photolysis of NO₃ under our conditions. We believe this to be the first observation using mass spectrometry of the NO₃ free radical. The quantum yield for atomic chlorine is φ = 1.0 ± 0.2. N₂O was used to test for O(¹D) according to the reaction, O(¹D) + N₂O → products; none was observed. Triplet oxygen, O(³P) was observed to the extent of ≈ 10% by the reaction O(³P) + NO₂ → NO + O₂, but this yield can also be due to the photolysis of NO₃ free radical produced in the primary step. We conclude that the predominant reaction pathway is

.     

有机分子与聚电解质静电吸附成膜特性研究

选取多种有机分子及聚电解质，采用静电吸附自组装法制备了聚电解质，聚电解质、聚电解质，有机分子、有机分子，有机分子的复合薄膜，讨论了这些体系的静电吸附成膜特性及其成膜机理．     

ELECTRON PARAMAGNETIC RESONANCE STUDIES OF SINGLE CRYSTAL SODIUM HEXAMOLYBDOCHROMATE (Ⅲ)Cr~(3+)/Na_3(AlMo_6O_(24)H_6)·8H_2O

An X-band EPR study on a Na_3(CrMo_6O_(24)H_6)·8H_2O single crystal diluted by its isomor-phic compound Na_3(AlMo_6O_(24)H_6)·8H_2O at room temperature is reported. Using the least squares-fitting method to simulate the EPR data for principal planes, the Hamiltonian parameterswere obtained. The principal values of the g tensors are g_(ZZ) = 1.904, g_(XX)= 1.973, g_(YY)=1.933. The zero field splitting tensor parameters are D = 0.275 cm~(-1), E = 0.05 cm~(-1). The fielddependence of Cr~(3+) energy levels with field at different angles from the principal axes whenthe field is along the principal planes is calculated based on these experimental parameters.The isofrequency plots of calculated field vs. angle are also shown. They agree well with theexperimental results.