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921.
While the thermal decomposition of NaHSO4 · H2O at 1 atm yields Na2S2O7 of ca. 90% purity only, it is possible to obtain products of 98% purity in vacuum at 170 C.
Herrn Professor. Dr. E. Asmus zum 60. Geburtstag gewidmet.
Das Bundesministerium für wissenschaftliche Forschung unterstützte in dankenswerter Weise die Arbeiten, in deren Rahmen die mitgeteilten Beobachtungen gemacht wurden. 相似文献
Herrn Professor. Dr. E. Asmus zum 60. Geburtstag gewidmet.
Das Bundesministerium für wissenschaftliche Forschung unterstützte in dankenswerter Weise die Arbeiten, in deren Rahmen die mitgeteilten Beobachtungen gemacht wurden. 相似文献
922.
F. Reinhardt 《Mikrochimica acta》1954,42(2):219-222
Zusammenfassung Es wird die papierchromatographische Trennung von Thiouracilderivaten beschrieben. Als Lösungsmittel wurde ein Benzol-Äthanolgemisch 166 verwendet. Eine Arbeitsweise wird angegeben, die der Flüchtigkeit dieses Lösungsmittels Rechnung trägt. Zur Entwicklung des Chromatogramms wird die Thiocarbamidreaktion mit Rutheniumchlorid verwendet.
Summary The paper chromatographic separation of thiouracil derivatives is described. A 166 mixture of benzene and ethanol is employed as solvent and a procedure is given that takes into account the volatility of this solvent. The thiocarbamide reaction with ruthenium chloride is used to develop the chromatogram.
Résumé On décrit la séparation chromatographique sur papier des dérivés du thio-uracile. Comme dissolvant, on utilise un mélange 166 benzène-éthanol suivant un mode opératoire donné qui tient compte de la volatilité de ce dissolvant. Pour le développement du chromatogramme, on utilise la réaction de la thio-urée avec le chlorure de ruthénium.相似文献
923.
Ralf Hollstein 《Archiv der Mathematik》1977,29(1):524-531
Ohne Zusammenfassung 相似文献
924.
Phase diagrams have been determined using differential thermal analysis for the binary systems CaCl2-KCl and CaCl2-CaCrO4. CaCl2-KCl phase diagrams have been previously reported but results were not consistent. No prior studies have been reported for the CaCl2-CaCrO4 system. In the CaCl2-KCl binary system two eutectics have been located at 24.0 mole % KCl (m.p. 615°C) and 74.3 mole % KCl (m.p. 594°C). A double salt of composition CaKCl3 melting congruently at 741°C has been found. The CaCl2-CaCrO4 system is a simple eutectic system with the eutectic occurring at 23.4 mole % CaCrO4 and melting at 660°C. 相似文献
925.
Rataboul F Zapf A Jackstell R Harkal S Riermeier T Monsees A Dingerdissen U Beller M 《Chemistry (Weinheim an der Bergstrasse, Germany)》2004,10(12):2983-2990
The synthesis and application of monodentate N-substituted heteroarylphosphines is described. In general, the ligands are conveniently prepared by selective metallation at the 2-position of the respective N-substituted heterocycle (pyrrole, indole) by using n-butyllithium/tetramethylethylenediamine (TMEDA) followed by quenching with dialkyl- or diarylchlorophosphines. Of the different ligands prepared, the new dialkyl-2-(N-arylindolyl)phosphines (cataCXium P) perform excellently in the palladium-catalyzed amination of aryl and heteroaryl chlorides. Coupling of both activated and deactivated chloroarenes proceeds under mild conditions (room temperature to 60 degrees C). By using optimized conditions remarkable catalyst productivity (total turnover number, TON, up to 8000) and activity (turnover frequency, TOF=14000 h(-1) at 75% conversion) are observed. 相似文献
926.
Baunemann A Thomas R Becker R Winter M Fischer RA Ehrhart P Waser R Devi A 《Chemical communications (Cambridge, England)》2004,(14):1610-1611
We report the precursor characteristics of a novel mononuclear mixed alkoxide compound [Hf(O(i)Pr)2(tbaoac)2] and its application towards MOCVD of HfO2 thin films in a production tool CVD reactor. 相似文献
927.
Nanotubes by template wetting: a modular assembly system 总被引:6,自引:0,他引:6
Steinhart M Wehrspohn RB Gösele U Wendorff JH 《Angewandte Chemie (International ed. in English)》2004,43(11):1334-1344
The wetting of porous templates with polymer melts and solutions or polymer-containing mixtures is a simple and versatile method for the preparation of tubular structures with diameters ranging from a few tens of nanometers to micrometers. The tube walls can be made of a multitude of materials, some of which have thus far been altogether impossible to use or very limited in their ability to be incorporated into nanostuctures. Template wetting also makes it possible to modify the nanotubes in a variety of ways, for example through the controlled generation of pores or the embedding of nanoparticles into the walls. This method offers a promising approach to functionalized nanotube-template hybrid systems and free-standing nanotubes. 相似文献
928.
Tedeschi C Li L Möhwald H Spitz C Von Seggern D Menzel R Kirstein S 《Journal of the American Chemical Society》2004,126(10):3218-3227
Intermolecular electron transfer is investigated in a dye-doped polyelectrolyte (PE) multilayer film. Hollow PE capsules, with a mean diameter of 2 microm, were prepared by stepwise adsorption of a pyrene (PY)-labeled polyanion and various polycations onto charged colloids and subsequent dissolution of the colloidal core. The high concentration of dye molecules within the capsule wall and the control of the medium polarity on a nanometer length scale are proposed to facilitate light-induced charge separation over distances of a few nanometers. In particular, a PY-labeled poly(styrene sulfonate) (PSS-PY) has been synthesized and used as polyanion for the polyelectrolyte capsule preparation. A polarity gradient across the wall of the PE shells is assumed to be achieved by adsorbing diverse polycations at different film positions. The high effective film area followed by high optical density of the PE capsule solution enables time-resolved optical spectroscopy. Using pulsed excited state absorption (ESA) the transient absorption peaks of the radical anion and cation state of pyrene were measured, respectively. In the presence of additional electron donor (or acceptor) molecules in the capsule solution the pyrene anion (cation) is observed in the ESA spectra, while both transient states are seen if no additional molecules are present. These results are interpreted as an electron transfer from pyrene to the donor (acceptor) molecule or between two pyrene molecules. An asymmetry of the electron donor and electron acceptor efficiency was observed when multilayer shells were used that are supposed to carry an internal polarity gradient. 相似文献
929.
It has been well established that the removal of center vortices from SU(2) lattice configurations results in the loss of confinement. The running coupling constant, gluon form factor, and ghost form factor are studied in the Landau gauge for the full and the vortex removed theory. In the latter case, a strong suppression of the running coupling constant and the gluon form factor at low momenta is observed, and the IR singularity of the ghost form factor disappears. Hence, the removal of the vortices generates a theory for which Zwanziger's horizon condition for confinement is no longer satisfied. 相似文献
930.