ELECTROCHEMICAL STUDY OF PYRAZOLONE DERIVATIVES AT THE LIQUID/LIQUID INTERFACE

Pyrazolone derivatives, such as antipyrine, aminopyrine, and 4-aminoantipyrine, can transfer across the water/nitrobenzene interface to produce a pair of well-defined symmetric, reversible anodic-cathodic peaks by cyclic voltammetri. The transfer mechanis

Cupric (II)-2,2 '-Biquinoline Transfer Across the Liquid/Liquid Interface and Kinetics of Complexation

Cupric (II) ion transfer across the water/nitrobenzene interface facilitated by 2,2'-biqulnoline was investigated by cyclic voltammtry. Transfer process was controlled by diffusion. At [BQ](NB)>>[Cu2+](W), transfer ion was found to be 1:2 Cu2+-biquinoline

ALKALI AND ALKALINE-EARTH METAL-ION TRANSFER ACROSS THE LIQUID-LIQUID INTERFACE FACILITATED BY IONOPHORE ETH157

The H+, Li+, Na+, K+, Mg2+, Ca2+ and Ba2+ ion transfer across the water/nitrobenzene (NB) and water/1,2-dichloroethane (DCE) interfaces, facilitated by the ionophore ETH157, has been investigated by cyclic voltammetry (CV). The mechanism of the transfer process has been discussed, and the diffusion coefficients and the stability constants of the complexes formed in the nitrobenzene phase have been determined.

ANESTHETIC LIDOCAINE AND DICAINE TRANSFER ACROSS LIQUID LIQUID INTERFACES

Lidocaine transfer across the water/1,2-dichloroethane and the water/nitrobenzene interfaces has been investigated by chronopotentiometry with linear current scanning and cyclic voltammetry. The irreversible hydrolysis occurring in the phase transfer of dicaine at the water/nitrobenzene interface is discussed.

SYNTHESIS, PROPERTIES AND MOLECULAR-STRUCTURE OF 5-COORDINATE N,N-DIBENZYLDITHIOCARBAMATE COMPLEXES OF TITANOCENE, ZIRCONOCENE AND HAFNOCENE

The five complexes (RC5H4)2M(S2CNBz2)Cl (R = H, CH3; M = Ti, Zr, Hf; Bz = CH2C6H5) have been prepared by the reaction of (RC5H4)2MCl2 with anhydrous sodium salts of dibenzyldithiocarbamate in refluxing CH2Cl2. These complexes have been characterized by elemental analysis, IR and H-1 NMR. X-ray crystal structure determination of Cp2Zr(S2CNBZ2)Cl shows the molecule has a five-coordinate bent metallocene geometry in which the zirconium atom is attached to two eta-5-C5H5 groups, one bidentate dibenzyldithiocarbamate ligand and one chlorine [Zr-Cl, 2.549(1) angstrom; Zr-S, 2.734(1), 2.667(1); Cl-Zr-S, 137.6(1)-degrees and 73.3(1)-degrees; S-Zr-S, 64.3(1)-degrees]. The catalytic system Cp2Ti (S2CNBZ2)Cl-NaH exhibits high initial catalytic activity of hydrogenation of hexene-1 under mild conditions.

ELECTROCHEMICAL STUDY OF CHOLINE DERIVATIVES TRANSFER ACROSS THE LIQUID LIQUID INTERFACE

Transfer behaviors across the water/nitrobenzene interface were studied for five choline derivatives by chronopotentiometry with linear current scanning, cyclic voltammetry and differential pulse voltammetry. The irreversible hydrolysis reactions coupled to the phase transfer of ions across the water/nitrobenzene interface were observed. The Gibbs energies of the transfer of choline derivatives show the effects of an additive constitution on hydrophobic property of the medicine.

ADVANCED ELECTROANALYTICAL CHEMISTRY IN CHINA .1. GENERAL ASPECT AND SOME METHODOLOGIES

The Research on Electroanalytical chemistry in China started mainly from the beginning of new China in 1949. It has already good basis and development nowadays. A review with references to the end of seventies has been published in "Reviews in Analytical Chemistry" 1) and in a book titled "Fifty years of Chinese Chemistry" edited by the Chinese Chemical Society in 1985 2). Since then more than thousand papers have been published, and it is impossible and also not necessary to describe all of them. This review only deals with the main progress of electroanalytical chemistry in China in recent years. Some new developed methodologies will be reviewed by S. Dong in the next article.

SYNTHESIS OF ALKALI-METAL HYDRIDES USING LANTHANIDE TRICHLORIDE-NAPHTHALENE AS CATALYST UNDER MILD CONDITIONS

The hydrogenation of alkali metals using lanthanide trichloride and naphthalene as catalyst has been studied. LnCl3(Ln = La, Nd, Sm, Dy, Yb) and naphthalene can catalyze the hydrogenation of sodium under atmospheric pressure and 40-degrees-C to form sodium hydride. The activities of lanthanide trichlorides are in the following order: LaCl3 > NdCl3 > SmCl3 > DyCl3 > YbCl3. Although lithium proceeds in the same catalytic reaction, the kinetic curve of the lithium hydrogenation is different from that of sodium. Lanthanide trichlorides display no catalytic effect on the hydrogenation of potassium in presence of naphthalene. The mechanism of this reaction has been studied and it is suggested that the anion-radical of alkali metal naphthalene complexes may be the intermediate for the hydrogenation of alkali metals and the function of LnCl3 is to catalyze the hydrogenation of the intermediate. The products are porous solids with high specific surface area (83 m2/g for NaH) and pyrophoric in air. They are far more active than the commercial alkali metal hydrides. The combination of these hydrides with some transition metal complexes exhibits high catalytic activity for the hydrogenation of olefins.

THE USE OF CHEMICALLY MODIFIED ELECTRODES FOR LIQUID-CHROMATOGRAPHY AND FLOW-INJECTION ANALYSIS

The use of chemically modified electrodes (CMEs) for liquid chromatography and flow-injection analysis is reviewed. Electrochemical detection with CMEs based on electrocatalysis, permselectivity, ion flow in redox films, and ion transfer across the water-solidified nitrobenzene interface is discussed in terms of improving the stability, selectivity, and scope of electrochemical detectors, and the detection of electroinactive substances. More than 90 references are included.

CYCLIC VOLTAMMETRIC STUDY ON THE TRANSFER MECHANISM OF ALKALI-METAL IONS ACROSS LIQUID LIQUID INTERFACE FACILITATED BY TRITON X-100

The transfer behavior of alkali motal ions K~+ and Na~+ across the interfaces of water/nitrobenzene and water/1, 2-dichloroethane facilitated by Triton X-100 is investigated by cyclic voltammetry with four electrodes. The equations of interfacial half-wave potential derived in terms of the mechanism proposed isverified by the experimental data and consistent with the practical △_0~wφ_p-pM curves.

KINETICS OF ION TRANSFER ACROSS LIQUID LIQUID INTERFACE BY CHRONOPOTENTIOMETRY WITH LINEAR CURRENT SCANNING

The equation of the potential-current curve for the ion transfer across the liquid/liquid interface during the linear current scanning has been derived theoretically. A method to calculate the kinetics parameters for the ion transfer by the way of linear current scanning is presented. The transfer of TPAs~+ ions, which is a typical basic electrolyte ion usually used in liquld/liquid interface electrochemistry, was practically investigated at the water/nitrobenzene interface.

ELECTROCHEMICAL-BEHAVIOR OF HETEROPOLY PHOSPHOMOLYBDOVANADATE ANIONS AT THE LIQUID LIQUID INTERFACE

Electrochemical transfer behavier of the V~vMo_(11)-V_5~vMo_7 heteropolyanions at the water/nitrobenzene interface has been investigated by using cyclic voltammetry. The effect of the solution acidity on the transfer behavior and the stable pH range of heteropolyanions were observed. Mixed melybdovanadate anions are more stable than 12-molybdophosphoric acid, however, the stability of the former decreases with increasing number of vanadium atoms. The main transfer species within the "potential window" has t...

加氢反应器壁原子氢分布的在线、实时、无损检测新技术

为了在线、实时、无损检测高温高压条件下运行的加氢反应器的多层器壁中原子氢的渗透速率和在任何指定剖面上的体浓度分布，发展了一种新型的检测技术．介绍了检测仪的结构设计及其特征。

Preparation of lanthanide hydrides of nanometric size by the catalytic method

Rare-earth metals were hydrogenated in the presence of TiCl4 catalyst in tetrahydrofuran (THF) at 45 degreesC under normal pressure. Transmission electron micrographs showed that the re. sulting lanthanide hydrides were in the form of nanoparticles. The rate of hydrogenation decreased with increasing atomic number of the rare-earth elements.

Thermal stability of nano-KH particles and their chemical reactivities

The variation of specific surface area and chemical reactivity of nano-KH particles treated at different temperatures has been studied, The BET surface area of nano-KH decreases with the increase of heat treatment temperature, while the chemical reactivity per unit surface increases steadily. These results indicate that the state of KH surface is changed after heat treatment. Large specific surface area of nano-KH is a major factor for its high chemical reactivity, nevertheless, the surface in an activated state with high surface energy is also an important factor for its high chemical reactivity. Nano-KH alone can polymerize styrene rapidly with the formation of polystyrene.