Verbandsisomorphismen endlicher auflösbarer Gruppen

Ohne ZusammenfassungHerrn Professor Dr.Reinhold Baer zum 70. Geburtstag     

Hydrogen exchange in intramolecular cycloalkylation of phenylalkanols

Hydrogen exchange in intramolecular cycloalkylation of 2-methyl-4-phenyl-2-butanol (I) and 2-methyl-5-phenyl-2-pentanol (II) in the presence of 85% D₂SO₄ has been studied. The product 1,1-dimethylindane(III) is shown to contain deuterium in both aromatic ring and polymethylene fragment, whereas 1,1-dimethyltetralin (IV) contains deuterium only in the aromatic ring. A probable mechanism of the reaction is discussed.

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2--4--2- (I) 2--5--2- (II) 85% D₂SO₄. , 1,1- (III) , 1,1- (IV) . .

     

Kinetisch-katalytische Bestimmungen in einem zweiphasensystem unter verwendung eines fallrohres

A rather simple method for kinetic-catalytic determinations is described, in which the reactants are dissolved in two immiscible liquid phases. Drops of the heavier phase fall through the lighter one contained in a vertical glass tube. As the drops fall, the reactants come into contact with each other at the interface, thus causing a change in the drops. The length of fall needed for completion of reaction is a measure of the concentration of the catalyst (e.g., decolorization of the drops in the determination of copper by the reaction between iron(III) and thiosulphate). If a gaseous reaction product is formed (e.g., N₂ or O₂) and adsorbed on the falling drop, then the drop stops falling and rises again. The depth of fall or the time needed for the drop to return to the upper end of the tube can be used as a measure for the concentration of catalyst (e.g., determination of thiosulphate with the iodine/azide reaction, or of copper as catalyst for the decomposition of hydrogen peroxide).     

Symmetry-relations and dynamics of molecular crystals in the long wave limit

Symmetry relations for macroscopic constants are derived. Especially it is shown that the Voigt-symmetry holds for the indices of the elastic constants. This has been doubted several times for lattices of particles with additional degrees of freedom. In the second part a simple model for Br₂- and J₂-lattices is discussed. The intermolecular forces are assumed to be van-der-Waals-forces. The influence of the internal degrees of freedom on lattice dynamics is calculated especially for the elastic constants. Further the limiting frequencies forq?0 are given and compared with experimental values.     

Eine Kennzeichnung der Projektoren endlicher auflösbarer Gruppen

Ohne Zusammenfassung