Activity evaluation of carbon paste electrodes loaded with pt nanoparticles prepared in different radiolytic conditions

Three Pt-based catalysts prepared in different radiolytic conditions and supported on graphite powder were packed into a carbon paste electrode configuration. They were compared to each other, to the commercial (Pt) deposited on activated carbon powder (Johnson Matthey) and to pure Vulcan XC-72 for their respective abilities toward the hydrogen evolution reaction (HER). The Tafel parameters were determined for all these electrodes. From the I–V curves and their quantitative treatment, the following order of activity emerged unambiguously and reads: (PtCO)₂ (fcc structure) > (PtCO)₁ (Chini cluster) > (Pt)_neat > (Pt)_JM (Johnson Matthey) ≫ (Vulcan XC-72). As expected, all the Pt-loaded electrodes were more efficient than Vulcan XC-72. The classification appears to be linked with the mean nanoparticle size, and for comparable sizes, with the surface morphology of the materials. The results and the stability of the electrodes suggest that the small particle sizes and the good dispersity on the carbon support were maintained during the HER.     

Studies on Solid State Reactions of Coordination Compounds（LXXI）──Solid State Reactions of o－Aminobenzoic Acid with Copper（Ⅱ） Acetate and Formate at Room Temperature

ＳｔｕｄｉｅｓｏｎＳｏｌｉｄＳｔａｔｅＲｅａｃｔｉｏｎｓｏｆＣｏｏｒｄｉｎａｔｉｏｎＣｏｍｐｏｕｎｄｓ（ＬＸＸＩ）──ＳｏｌｉｄＳｔａｔｅＲｅａｃｔｉｏｎｓｏｆｏ－ＡｍｉｎｏｂｅｎｚｏｉｃＡｃｉｄｗｉｔｈＣｏｐｐｅｒ（Ⅱ）ＡｃｅｔａｔｅａｎｄＦｏｒｍ...     

Stereoselective electrocatalytic cyclization of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acid esters to form 6-substituted (1R,5R,6R)*-4,4-dialkoxy-5-cyano-2-oxo-3-azabicyclo[3.1.0]hexane-1-carboxylic acid esters

Electrolysis of 3-substituted 2,2-dicyanocyclopropane-1,1-dicarboxylic acid esters in alcohols in an undivided cell in the presence of NaBr or NaOAc afforded 6-substituted (1R,5R, 6R)*-4,4-dialkoxy-5-cyano-2-oxo-3-azabicyclo[3.1.0]hexane-1-carboxylic acid esters in 80–95% yields. Published in Russian in Izvestiya Akademii Nauk. Seriya Khimicheskaya, No. 1, pp. 102–107, January, 2006.     

WS2 超细粉体的固相法合成

WS2 超细粉体的固相法合成;WS2;固相反应;过硫系数;高能球磨;粒度     

Detection of processed genetically modified food using CIM monolithic columns for DNA isolation

The availability of sufficient quantities of DNA of adequate quality is crucial in polymerase chain reaction (PCR)-based methods for genetically modified food detection. In this work, the suitability of anion-exchange CIM (Convective Interaction Media; BIA Separations, Ljubljana, Slovenia) monolithic columns for isolation of DNA from food was studied. Maize and its derivates corn meal and thermally pretreated corn meal were chosen as model food. Two commercially available CIM disk columns were tested: DEAE (diethylaminoethyl) and QA (quaternary amine). Preliminary separations were performed with standard solution of salmon DNA at different pH values and different NaCl concentrations in mobile phase. DEAE groups and pH 8 were chosen for further isolations of DNA from a complex matrix-food extract. The quality and quantity of isolated DNA were tested on agarose gel electrophoresis, with UV-scanning spectrophotometry, and by amplification with real-time PCR. DNA isolated in this way was of suitable quality for further PCR analyses. The described method is also applicable for DNA isolation from processed foods with decreased DNA content. Furthermore, it is more effective and less time-consuming in comparison with the existing proposed methods for isolation of DNA from plant-derived foods.     

Highly regio- and stereocontrolled SN2′ reactions of gem-difluorinated vinyloxiranes with monoalkylcopper reagents

Reaction of gem-difluorinated vinyloxiranes with RCu(X)Li allowed us to introduce the R group regioselectively at the fluorine-attached terminal carbon atom in an S_N2′ manner to afford (E)-allylic alcohols exclusively, while homoallylic alcohols with anti stereochemical relationship were found to be obtained selectively from higher-ordered cuprates derived from CuCl and RMgBr in a ratio of 1:3.     

微波辐射促进ZnCl_2与Y分子筛固相反应的研究

采用XRD、IR和原子吸收光谱等手段对微波固相法制备的ZnCl2／Y催化剂进行了表征·微波辐射促进了ZnCl2在分子筛表面分散和固态离子交换，分散的ZnCl2可与分子筛表面氧原子发生较强的配住键合作用．当ZnCl2的负载量达到37．5％时，ZnCl2仍可完全分散于NaY分子筛表面，此时的固态离子交换度为84％．随着分子筛表面酸菌和区强度的增加，ZnCl2与分子筛的固态离子交换量减少．     

1-(2-苯并噻唑)-3-(4-偶氮苯基)-三氮烯与汞的显色反应研究及应用

研究了新试剂１－（２－苯并噻唑）－３－（４－偶氮苯基）－三氮烯（ＢＴＰＡＰＴ）与汞的显色反应．在Ｔｗｅｎ－８０存在下，ｐＨ为１１．２０时，Ｈｇ（Ⅱ）与试剂生成红色的１∶１型配合物，最大吸收峰位于５１０ｎｍ，表观摩尔吸光系数为１．１０×１０５Ｌ·ｍｏｌ－１·ｃｍ－１，线性范围０－１４μｇ／２５ｍＬ．建立了可用于饮用水、生活用水和工业废水汞含量测定的方法．