Verteilungskoeffizienten im System Wasser/Toluol/n-Heptan/Zeolith NaX

Ohne Zusammenfassung     

UR-Spektren des Schmelzwassers

Ohne Zusammenfassung     

Radikalische Copolymerisation der Vinylmonomeren in Gegenwart der Komplexbildner

Ohne Zusammenfassung     

The Theory of Ionization Waves in the Contracted Discharge of Noble Gases

Positive column plasma in noble gases at middle pressures is analysed for stability in the frames of the linear hydrodynamic theory. At critical values of pressure and current the discharge becomes unstable to radial contraction (contraction) and to wave disturbances of the type of current pinch constrictions (contraction ionization waves). Ionization waves in the contracted discharge are three-dimensional formations with electron concentration oscillations on the axis in the opposite phase with current pinch cross section. The discharge diffuse-recombination theory was used for analysing the problem of instability arising.     

Untersuchungen von verdampfungs- und plasmaprozessen in der graphitrohrküvette zur optimierung von AA-bestimmungen—II. Molekülabsorptions-spektrometrische und atomabsorptions-spektrometrische untersuchungen an wäßrigen Lösungen und organischen extrakten des galliums und indiums

The authors compared the sensitivities achieved in the determination of Ga and In by AAS with electrothermal atomization in graphite cuvettes in dependence on the solvent, i.e. some acids and organic extracts. The best sensitivity was found in an HNO₃ environment. Signal depressions were observed especially in the presence of halides and with solvents containing halogens. The results of the investigations showed that the principal cause of the depressions is the formation of stable molecules of the type MX (M = Ga or In; X = Cl or Br) in the gaseous state. A second cause is the evaporation. The temperature, in particular that prevailing during the ashing step affects the X-concentration in the gaseous state because of thermal hydrolysis of unstable salts or evaporation of the organic solvents.     

Lewis acid mediated reactions of aldehydes with styrene derivatives: synthesis of 1,3-dihalo-1,3-diarylpropanes and 3-chloro-1,3-diarylpropanols

[reaction: see text] The reactions of aryl aldehydes with styrene derivatives, mediated by various boron Lewis acids, were investigated. 1,3-Dihalo-1,3-diarylpropanes were obtained in high yields with boron trihalides, while 3-chloro-1,3-diarylpropanols were obtained in good to excellent yields with phenylboron dichloride. Reactions involving nonenolizable aliphatic aldehydes, trans-cinnamaldehyde, and beta-substituted styrenes were also investigated for the first time.     

Synthesis and efficiency of a chelating fiber for preconcentration and separation of trace Au(III) and Pd(IV) from solution samples

A novel poly(acryl-benzoylamidrazone-acryl-benzoylhydrazine) chelating fiber was synthesized simply from nitrilon (polyacrylonitrile fiber). The structure of the chelating fiber was verified with the help of FT-IR spectrum. The parameters influencing the efficiency of the fiber for concentrating trace amounts of Au(III) and Pd(IV) were investigated in detail. Trace Au(III) and Pd(IV) were enriched and separated from real sample solutions and detected using inductively coupled plasma atomic emission spectrometry (ICP-AES) with satisfactory results. The experiments show that the method is rapid, precise, simple and convenient to use.