Ionic medium effects on equilibrium constants Part I. Proton, copper(II), cadmium(II), lead(II) and acetate activity coefficients in aqueous solution

The molar single ion activity coefficients associated with hydrogen, copper(II), cadmium(II) and lead(II) ions were determined at 25 degrees C and ionic strengths between 0.100 and 3.00 M (NaClO4), whereas for acetate the ionic strengths were fixed between 0.300 and 2.00 M, held with the same inert electrolyte. The investigation was carried out potentiometrically by using proton-sensitive glass, copper, cadmium and lead ion-selective electrodes and a second-class Hg|Hg2(CH3COO)2 electrode. It was found that the activity coefficients of these ions (y(i)) can be assessed through the following empirical equations: log y(H) = -0.542I(0.5) + 0.451I; log y(Cu) = -1.249I(0.5) + 0.912I; log y(Cd) = -0.829I(0.5) + 0.448I(1.5); log y(Pb) = -0.404I(0.5) + 0.117I(2); and log y(Ac) = 0.0370I     

Determination of nafcillin and methicillin by different spectrofluorimetric techniques

In order to explore the possibilities of combining synchronous fluorescence and derivative spectrometry and to establish a methodology for this type of technique, nafcillin and methicillin were determined using these techniques. Several methods for resolving binary mixtures of these penicillins using first derivative spectrofluorimetry, first derivative constant wavelength synchronous luminescence spectrometry and constant energy synchronous luminescence spectrometry are described. The analyses were performed in aqueous medium at pH 6.20 provided by the addition of phosphate buffer solution. A complete and exhaustive statistical analysis of the experimental data was performed to demonstrate the validity of these methods, which obtained good results when applied for determining nafcillin and methicillin synthetic and real mixtures.     

镍钴氢氧化物的制备及其电化学性能

采用化学共沉淀法成功制备了片状镍钴氢氧化物,并探究了不同镍钴物质的量比对样品形貌及电化学性能的影响。通过X射线衍射(XRD)、扫描电子显微镜(SEM)、X射线光电子能谱仪(XPS)及比表面积孔径分析仪(BET)对样品的结构、形貌进行了表征,并利用循环伏安法、恒电流充放电法等对其电化学性能进行了分析。结果表明,n(Ni)∶n(Co)=4∶1的样品直接用作电极材料时,具有最好的电化学性能:在0.5 A/g的电流密度下拥有1852 F/g的高比容量;电流密度增大20倍时,仍拥有1330 F/g的高比容量。以镍钴氢氧化物为正极,活性炭为负极组装的非对称式超级电容器在346 W/kg的功率密度下,能量密度达52 Wh/kg,在循环10000圈之后电容保持率为92%。优异的电化学性能表明,片状镍钴氢氧化物是很有应用潜力的电极材料之一。     

Asymmetric Diethylzinc Addition to N-Diphenylphosphinoyl Benzalimine Mediated by Imino Alcohols

As our continuous efforts to search for easily accessible ligands for dialkylzinc addition to imines,[1] in this paper,we would like to present a family of chiral imino alcohols 3 derived from 1,2-diphenyl-2-aminoethanol which will be evaluated for the titled reaction. We believed that this kind of chiral ligands could be good chiral ligands for the diethylzinc addition to imines based on two points: (1) The excellent asymmetrically inductive properties of 1,2-diphenyl-2-aminoethanol and its derivatives have been proven in many reactions. (2) The conformation of the nitrogen in the chiral imines 3 is restricted by imine function which is similar to chiral oxazolines reported in our recent work.     

三唑类化合物研究与应用

综述了三唑类化合物在医药、农药、化学等相关领域的研究与应用。参考文献82篇。     

微型非水滴定法测定喷昔洛韦钠原料药含量

本文采用微型非水滴定法测定了喷昔洛韦钠原料药的含量,所得结果与常量非水滴定法和pH指示剂吸光度比法结果一致。微型滴定法试剂消耗少,分析成本低,也可降低环境污染,适于作为喷昔洛韦钠原料药含量的测定方法,有推广应用价值。     

Hydrocondensation of CO on iron-alumina catalysts. Influence of ethylene

The transformations of H₂/C₂H₄ and H₂/C₂H₄/CO mixtures on activated and carbided 10% Fe/Al₂O₃ catalysts have been studied in terms of the role of ethylene in Co hydrocondensation, and specifically its influence on the selectivity to C₃–C₄ hydrocarbons.

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H₂/C₂H₄ H₂/C₂H₄/CO 10% Fe/Al₂O₃ CO C₃–C₄ .

     

Direct determination of salicylamide in serum by matrix isopotential synchronous fluorimetry

A method for the determination of salicylamide at concentrations between 25 and 350 ng ml(-1) by use of matrix isopotential synchronous fluorescence spectrometry (MISF) in combination with derivative techniques is proposed. The method allows the determination of compounds in samples with unknown background fluorescence without the need for tedious pre-separation. Synchronous scans are performed along a trajectory that connects points of identical intensity in a three-dimensional fluorescence spectrum. The unknown analytical signal of the serum is suppressed from the MISF spectrum, by calculating its first derivative at lambda(exc)=324 nm and lambda(em)=392 nm. In order to ensure maximum sensitivity and adequate selectivity, the experimental variables affecting the fluorescence intensity of the salicylamide band at lambda(exc)=328 nm and lambda(em)=418 nm were studied. Based on the results, the determination was performed in an aqueous medium at pH 12 that was adjusted with a sodium phosphate/hydrogen phosphate buffer. Calibration graphs were subjected to a comprehensive statistical analysis. The error propagation has been considered in order to calculate the detection limit by the criterium of Clayton.