Formation mechanism of hexafluoropropylene oxide in low-temperature liquid-phase oxidation of hexafluoropropylene by molecular oxygen

A kinetic model has been developed for describing the non-catalytic solid-liquid reaction of aspartic acid with potassium hydroxide in solutions. It takes into consideration the effects of the aspartic acid particle size distribution by using the population balance approach. The parameters of the model have been estimated by fitting them to experimental data taken from literature.

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Role of tellurium in the oxidation of 1-butene on Te-doped CdMoO4

New active and selective catalysts were prepared by adding different quantities of Te to CdMoO₄. These were already selective at low Te levels, but the one with a Cd/Te/Mo ratio of 1/1/1 was specific for butadiene. The catalytic behavior of the Cd–Te–Mo–O system has been correlated mainly with the CdTeMoO₆ phase in the region rich in Te and with the CdMoO₄ phase with Te as dopant in the region poor in Te.

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Te CdMoO₄. Te, CdTeMo=111 . Cd–Te–Mo–O CdTeMoO₆ Te, CdMoO₄ Te , Te.

     

Self-oscillations in the cool-flame combustion of a model n-heptane-isooctane mixture

Self-oscillation found experimentally in the cool-flame combustion of a model n-heptane-i-octane mixture has been studied in dependence on the composition of the reaction mixture. Calculations based on the CSTR model are in qualitative agreement with experimental data.

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二芳基汞的合成

将氯化重氮苯的溶液加入氯化汞、维生素C、丙酮和少量氯化铜的混合物中,得到80％的氯化苯汞;如在反应混合物中补加维生素C、氯化铜和浓氨水,则得到二苯汞。用同样的方法制备了其他的二芳基汞,并讨论了反应可能的机理。     

Effect of substituents (NH_2,OH,F) on structures and stability of lithofluorosilylenoids

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Determination of cobalt(II) in parts per billion range by fluorescence extinction

Summary A fluorescence extinction method for the determination of cobalt(II) in the parts per billion range has been developed. The method is based on the reaction between cobalt(II) and the fluorescent aluminum-Superchrome Blue Black Extra complex. The fluorescence intensity of the complex decresases sharply in the presence of cobalt(II), the decrease being linear over a concentration range of 0.001 g to 0.02 g per ml of final solution. The effect of p_H and diverse ions ion the accuracy and reproducibility of the method has been investigated and the empirical formula of the cobalt-dye complex tentatively evaluated.

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Zusammenfassung Es wurde ein Verfahren zur Kobalt(II)-bestimmung im ppb-Bereich durch Fluorescenz-Extinktion entwickelt. Grundlage des Verfahrens ist die Reaktion zwischen Kobalt(II) und dem fluorescierenden Komplex aus Aluminium und Superchrome-Blauschwarz-Extra. Die Pluorescenz dieses Komplexes wird durch Kobalt(II) stark geschwächt, wobei die Schwächung im Konzentrationsbereich 0,001–0,02 g Co/ml Endlösung linear verläuft. Der Einfluß des p_H-Wertes sowie verschiedener Ionen auf die Genauigkeit und Reproduzierbarkeit wurde untersucht und die empirische Zusammensetzung des Kobalt-Farbstoffkomplexes wurde versuchsweise ausgewertet.

     

Mass spectrometry of carbohydrate derivatives

Mass spectra of carbohydrate methyl ethers of different types and other monosaccharide derivatives have been measured. Fragmentation patterns of these compounds, characteristic features of their mass spectra and potential analytical importance of mass spectrometry for structural study in the carbohydrate field are discussed.     

Modification of Amaya-Sugiura passive sampling spectrophotometric method of nitrogen dioxide determination in ambient air

Summary On the example of the previously tested method of nitrogen dioxide determination in ambient air two aspects of wind influence on the badge-type sampler performance were discussed: an appropriate design of the sampler eliminating any open recess over the face of the sampler and so called starvation effect i.e. decrease in the mass of analyte absorbed by the sampler at wind velocities below 20 cm/s. The wind effect on the performance of the passive sampler has been diminished from about 150% to maximum 20%.     

Strong H2 chemisorption on Al2O3 or SiO2 supported group VIII metals

Following hydrogen treatments at high temperature a decrease in hydrogen chemisorption at room temperature is observed in almost all group VIII elements supported on SiO₂ or Al₂O₃. The effect is attributed to self inhibition by strongly chemisorbed hydrogen on the metals.

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VIII , SiO₂ Al₂O₃. .