Titrations with piezoelectric monitoring : Part 2. Compleximetric titrations and precipitation titrations

A piezoelectric detector is used to monitor titration reactions involving complex formation or precipitation. Analytes at concentrations down to 10^?4 mol 1^?1 can be determined. The frequency shift in the compleximetric titrations is affected by the composition of the solution, the buffer and competing ligands present in the solution. Factors influencing the frequency shift in the precipitation titration are also investigated.     

杯[4]芳烃锥形骨架在光学受体识别中的作用

比较研究了铜、镍的杯[4]芳烃光学受体及其单体的分析性能，并进一步探讨了杯[4]芳烃的锥形骨架在分子识别中的作用。结果表明，通过分子设计，将杯[4]芳烃锥形骨架合理地引至光学受体中，可以起到立体屏障作用，能有效阻止其它客体在一些方向上靠近配位反应点所带来的干扰，从而对客体的选择性识别提供重要贡献。     

Theory of the surface acoustic wave/impedance sensor system and its application to the end-point determination in titrimetry

Theory and characteristics of the surface acoustic wave (SAW)/impedance sensor system in electrolyte solution are reported. This kind of sensor was constructed by a 62-MHz SAW resonator and a pair of conductive electrodes in series. By using the circuit network analysis theory, two oscillation equations were derived and used to explain the frequency-shift response to solution conductance. Results showed that the sensor possesses high sensitivity to the solution conductivity and can be applied to conductivity measurements in solution. Its sensitivity and accuracy could be improved in the presence of a large amount of unreacting foreign electrolytes. The sensor was successfully applied to four types of titration (acid-base, precipitation, oxidation-reduction and compleximetric titration) by monitoring the frequency-shift response. Factors influencing the frequencimetric titration curve were also investigated. Analytes at levels down to 1 × 10⁻⁵ M could be determined by the proposed titration technique. The total acidity in several food samples was determined and the results were consistent with those obtained by conventional methods.     

手性Ru复合物催化剂的固载化及其不对称氢转移反应催化应用

Chiral Ru-BsDPEN, (1R,2R)-N-p-benzenesulfonyl-1,2-diphenylethylenediamine, catalyst has been immobilized on a mesoporous molecular sieve of MCM-41 type successfully. A hybrid mesoporous molecular sieve was synthesized using a precursor bearing benzene group, which in organosilica were sulfonylated and reacted with (1R,2R)-l,2-diphenylethylenediamine and [RuC1E(p-cymene)]2 successively to afford immobilized catalyst. The Brunauer-Emmett-Teller (BET) surface area and Barrett-Joyner-Halenda (BJH) pore size decreased after immobilization of catalyst onto the mesoporous material. Enantioselective transfer hydrogenation of ketones catalyzed by immobilized catalyst showed the highest yield of 22.36% and e.e. value of 31.47% by using acetophenone as substrate when reaction time was 48 and 16 h respectively.     

激光对火焰的诊断Ⅱ. 激光诱导荧光法对液化石油气/空气火焰中的OH基浓度二维分布的检测

通过部份预混的富燃料液化石油气/空气火焰中各部份的OH(A~(2∑~+)←→X ~(2Π))的激光诱导荧光信号进行逐点检测, 获得了OH(X)基在火焰中央纵剖面上精细的二维等浓度线图。OH(X)在外焰边缘上分布最浓, 是自内向外扩散的H原子与O原子相遇而引起反应的结果。同时一部份OH(A)基的生成, 发出了紫外的A→X化学发光, 形成了外焰的轮廓。     

Behaviour of series piezoelectric sensor in electrolyte solution : Part II. Applications in titrimetry

The applications of a series piezoelectric sensor for end-point determination in frequencimetric titrations, including neutralization, precipitation, complexation and redox titrations, are reported. The method is based on the fact that a series piezoelectric sensor shows a sensitive and selective frequency response to changes in conductivity of solution and can be applied to sample solutions containing large amounts of unreacted foreign electrolytes.     

Intramolecular π–π stacking in diaquabis(2‐hydroxybenzoato‐κO)bis(1,10‐phenanthroline‐κ2N,N′)strontium(II)

In the title compound, [Sr(C₇H₅O₃)₂(C₁₂H₈N₂)₂(H₂O)₂], the Sr^II ion is located on a twofold rotation axis and assumes a distorted square‐antiprism SrN₄O₄ coordination geometry, formed by two phenanthroline (phen) ligands, two 2‐hydroxybenzoate anions and two water molecules. Within the mononuclear complex molecule, intramolecular π–π stacking is observed between nearly parallel coordinated phen ligands, while normal intermolecular π–π stacking occurs between parallel phen ligands of adjacent complex molecules. Classic O—H...O and weak C—H...O hydrogen bonding helps to stabilize the crystal structure.     

废旧镍镉电池真空蒸馏规律的研究

在实验室条件下，对镍镉电池的真空蒸馏基本规律进行了探索.分析了温度、压力和时间等工艺因素对镍镉分离效果的影响，并对镍镉电池的真空蒸馏机理进行了研究，为废旧镍镉电池资源化提供了理论依据和实验数据.     

A conductance sensor for dissolved sulphur dioxide using a series piezoelectric crystal device

A new piezoelectric crystal impedance sensor for the determination of sulphur dioxide in aqueous solution is presented. It is realized using a series piezoelectric crystal device which is constructed by connecting an AT-cut piezoelectric crystal to a probe in series. The probe is filled with an internal electrolyte solution that is separated from sample solutions by a gas-permeable membrane. The present sensor exhibits a favourable frequency response to 1 x 10(-7)-1 x 10(-3) M sulphur dioxide. The detection limit is 1 x 10(-8) M. The effects of the sensor preparation are considered. Dynamic range, reproducibility, response time and selectivity of the sensor are also discussed. The proposed sensor has been used successfully for lamp sulphur determinations in petroleum samples.     

1,5-二氮杂双环[4,3,0]壬碳-5-烯与全氟炔酸酯的反应及其产物的核磁共振研究

1，5—二氮杂双环[4，3，0]壬碳—5—烯(DBN)与全氟炔酸酯反应生成成环化合物。通过对成环产物的^1HNMR、^13C NMR及相关的2D NMR谱的分析，确证了该类化合物的结构，并讨论了其化学位移及J-偶合特征。同时提出了整个反应可能的历程和机理。