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  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Rapid Communications in Mass Spectrometry 9 (1995), S. 697-702 
    ISSN: 0951-4198
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Physics
    Notes: Matrix-assisted laser desorption/ionization mass spectrometry was used for the characterization of extracted and synthesized oligo(ethylene terephthalate)s. Generally, cyclic oligomers [GT]n could be found in technical yarns and tiles, whereas our synthesized model oligomers mainly consisted of linear chains H—[GT]n—G. In addition, some other distributions could be identified as H—[GT]n—OH and H—[GGT]1—[GT]n-1—G linear oligomers and H—[GGT]1—[GT]n-1 cyclic oligomers, where G is an ethylene glycol unit, GG is a diethylene glycol unit, caused by impurities of ethylene glycol, and T is a terephthalic acid unit. NMR and IR investigations were carried out to verify these results.
    Additional Material: 5 Ill.
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 30 (1979), S. 470-477 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In the plasma of electrical discharges polymer samples are subjected to oxidation causing reactive sites or to degradation. Further, a significant volume (depth) effect in a 5 to 10 μm surface layer was observed which was caused by plasma UV radiation. These photolytical effects result in changes of the polymer structure, as crosslinking, change of crystallinity, radical formation etc. Therefore, the etching patterns reflect the features of secondary structures formed by these processes.
    Notes: Polymere werden im Plasma einer elektrischen Entladung an der Oberfläche funktionalisiert (oxydiert) bzw. abgebaut. Daneben wurde jeweils ein signifikanter, auf eine 5 bis 10 μm starke Schicht an der Oberfläche beschränkter Volumeneffekt („Tiefeneffekt“) beobachtet, der durch die Plasma-UV-Strahlung verursacht wird. Diese photolytischen Erscheinungen führen zu Änderungen im Polymergefüge wie Vernetzung, Veränderung der Kristallinität, Radikalbildung usw. Abbildungen von Polymerätzstrukturen spiegeln deshalb in gewissem Umfang die solchermaßen veränderte Sekundärstruktur wider.
    Additional Material: 10 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 40 (1989), S. 397-401 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: A model of the reaction between glycidylethers and aromatic cyanates is established. It was found that the trimerization of cyanates, the insertion of glycidylethers, the isomerisation of alkylcyanurates, the oxazolidinone build up, the abstraction of the phenols, and the phenol/glycidylether-addition are the main reactions.
    Notes: Ein Reaktionsmodell der Umsetzung von Glycidethern mit aromatischen Cyansäureestern wird begründet. Als Hauptreaktionen wurden die Trimerisierung der Cyansäureester, die Einschubreaktion der Glycidether in die Cyanuratstruktur, die Isomerisierung der Alkylcyanurate, die Oxazolidinonbildung, die Phenolabspaltung und die Phenol/Glycidether-Addition gefunden.
    Additional Material: 3 Ill.
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Acta Polymerica 37 (1986), S. 715-719 
    ISSN: 0323-7648
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Die Kinetik der thermischen Polycyclotrimerisierung von 2,2-Bis(4-cyanatophenyl)propan wurde mit Hilfe von DSC und IR-Spektroskopie untersucht. Der autokatalytische Charakter der Reaktion wurde durch Modellierung der Umsatz-Zeit-Kurven bei Zusatz difinierter Mengen der nachgewiesenen Zwischenprodukte aufgeklärt. Weiterhin wurden quantitative Beziehungen zwischen Reinheitsgrad des Dicyanats, Geschwindigkeit der Bruttoreaktion, Lage des DSC-Maximums und B-Zeit gefunden.
    Notes: The kinetics of polycyclotrimerization of 2,2-bis(4-cyanatophenyl)propane was analyzed by differential scanning calorimetry and IR spectroscopy. The autocatalytic character of the reaction was elucidated by modelling the conversion-time curves of systems with definite admixtures of the found intermediate products. Furthermore, quantitative relations between the purity of the dicyanate, the rate of the brutto reaction, the temperature of the DSC maximum, and the B-time of the resin were found.
    Additional Material: 6 Ill.
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  • 5
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 531 (1985), S. 61-66 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Herstellung, Struktur und Infrarot-Gitterschwingungen von LiInTe2Die ternäre Verbindung LiInTe2, durch direkte Reaktion der Elemente synthetisiert, kristallisiert in der tetragonalen Chalkopyritstruktur (Raumgruppe I42d) mit den Gitterparametern a = 0,6419(2) nm und c = 1,2486(3) nm. LiInTe2 verbleibt bis zur Schmelztemperatur von (935 ± 5) K in der Chalkopyritstruktur. Im Wellenzahlbereich von 40 bis 4000 cm-1 aufgenommene Infrarot-Reflexionsspektren ergeben zwei infrarotaktive optische Moden. Eine Analyse der Modenfrequenzen im Rahmen des Keating-Modells zeigt, daß die Li—Te-Bindung wesentlich schwächer als die In—Te-Bindung ist.
    Notes: The ternary compound LiInTe2, synthesized by direct reaction of the elemental components, crystallizes in the tetragonal chalcopyrite structure (space group I42d) with lattice parameters a = 0.6419(2) and c = 1.2486(3) nm. LiInTe2 remains in the chalcopyrite structure up to the melting temperature of (935 ± 5) K. Infrared reflectance spectra measured in the wavenumber range from 40 to 4000 cm-1 yield two infrared active optical modes. An analysis of the mode frequencies in terms of the Keating model shows that the Li—Te bond is considerably weaker than the In—Te bond.
    Additional Material: 2 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 35 (1997), S. 2183-2192 
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hydrolytic degradation of technical poly(ethylene terephthalate) (PET) was investigated by means of different methods such as size-exclusion chromatography (SEC), viscometry, light-scattering, thin-layer chromatography, end-group titration, and matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS). The long-term degradation was simulated by exposing PET filament yarns to aqueous neutral conditions at 90°C for up to 18 weeks. By means of MALDI-MS and thin-layer chromatography, the formation of different oligomers was obtained during polymer degradation. As expected, an ester scission process was found generating acid terminated oligomers (H-[GT]m-OH) and T-[GT]m-OH and ethylene glycol terminated oligomers (H-[GT]m-G), where G is an ethylene glycol unit and T is a terephthalic acid unit. Additionally, the scission of the ester bonds during the chemical treatment led to a strong decrease in the number of cyclic oligomers ([GT]m). The occurrence of di-acid terminated species demonstrated a high degree of degradation. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 2183-2192, 1997
    Additional Material: 10 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 38 (1968), S. 222-232 
    ISSN: 0021-8383
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Es wird über die Synthese einiger Diarylphosphinsäureanilide berichtet. Für die kinetische Untersuchung der säurekatalysierten Spaltung dieser Verbindungen wurde eine UV-spektroskopische Methode ausgearbeitet. Für diese Reaktion wurden bestimmt: Geschwindigkeitskonstanten, Aktivierungsenergie, -entropie, Deuteriumoxid-Lösungsmittelisotopen-effekt, Abhängigkeit der Geschwindigkeit von der Säurekonzentration. Der Mechanismus wird diskutiert.
    Additional Material: 4 Ill.
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 350 (1967), S. 27-34 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Transition metal ions form crystalline chelates with the methylester of o-mercaptobenzoic acid. The suggested ligand behaviour as a β-thioxoketone with fixed thioenol structure is supported by IR-spectroscopic measurements. The stability of the nickel(II) chelate has been determined by ligand exchange with pyridine and ethylenediamine. Copper(II) chloride and nitrate or perchlorate form 1:1 and 1:2 complexes, respectively, with the methylester of o-aminobenzoic acid, which have been isolated and compared with the mercapto compounds.
    Notes: Übergangsmetallionen reagieren mit o-Mercaptobenzoesäuremethylester unter Bildung Kristalliner Komplexe. IR-spektroskopische Untersuchungen bestätigten die Vermutung, daß sich der Ligand wie ein β-Thioxoketon mit fixierter Thioenolstruktur verhält. Durch Ligandenaustausch gegen Pyridin und Äthylendiamin wurde die Stabilität des Bis-(o-mercaptobenzoesäuremethylester)-nickel(II) untersucht. Zum Vergleich wurden vom o-Aminobenzoesäuremethylester ein 1:1-Komplex mit Kupfer(II)-chlorid und 1:2-Komplexe mit Kupfer(II)-nitrat bzw. -perchlorat dargestellt und die Verschiebungen der C=O-Valenzfrequenz diskutiert.
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 504 (1983), S. 155-162 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Investigation of CuGaSe2 and CuGaTe2 under High PressureThe X-ray powder diffraction analysis at 300 K in dependence on the pressure gives a transition from the chalcopyrite-type to the NaCl structure for CuGaSe2 at 12.5 GPa and for CuGaTe2 at 8 GPa. The phase transition is associated with a discontinuity of the volume of 8.6 and 3.8%. These results were discussed in relation to other tetrahedrally coordinated compounds.
    Notes: Röntgenuntersuchungen bei 300 K in Abhängigkeit vom Druck ergaben, daß CuGaSe2 bei 12,5 GPa und CuGaTe2 bei 8 GPa von der Chalcopyrit-Struktur in die NaCl-Struktur übergehen. Dabei tritt ein Volumensprung von 8,6 bzw. 3,8% auf. Diese Ergebnisse werden im Zusammenhang mit Hochdruckuntersuchungen an anderen tetraedrisch koordinierten Verbindungen diskutiert.
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Zeitschrift für anorganische Chemie 513 (1984), S. 57-66 
    ISSN: 0044-2313
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Complex Catalysis. XIX. Synthesis of Nitrosyl Complexes of Tungsten and their Usefulness as Precatalysts for Olefin MetathesisNitrosylating reduction of WCl6 with NO leads to WCl3(NO)4 that on addition of different donor ligands L yields complexes of the types WCl3(NO)L2 (L = OOh3, HMPT, pyridine) and WX2(NO)2 L2 (L = PPh3, X = Cl; XL = acac) or mixtures of products (L = Dipy, RCN, Et4NCl), respectively. Whereas by carbonylation of WCl3(NO)(OPPh3)2 in the presence of EtAlCl2 only chloro carbonyl tungsten complexes are formed, the reaction of W(CO)6 with NOAlCl4 and subsequent addition of PPh3 gives, in analogy to molybdenum, the nitrosyl carbonyl complexes W(NO)(CO)4(AlCl4) and WCl(NO)(CO)2(PPh3)2. All the nitrosyl tungsten complexes in combination with EtAlCl2 catalyze the metathesis of pent-2-ene, however, with a significantly lower activity than the corresponding nitrosyl molybdenum systems.
    Notes: Die nitrosylierende Reduktion von WCl6 mit NO führt zu WCl3(NO)4, das mit verschiedenen Donorliganden L zu Komplexen der Typen WCl3(NO)L2 (L = OPPh3, HMPT, Pyridin) und WX2(NO)2L2 (L = PPh3; X = Cl; XL = acac) bzw. zu Produktgemischen (L = Dipy, RCN, Et4NCl) reagiert. Während die Carbonylierung von WCl3(NO)(OPPh3)2 in Gegenwart von EtAlCl2 Chlorocarbonyl-wolfram-Komplexe liefert, lassen sich in Analogie zum Molybdän durch Umsetzung von W(CO)6 mit NOAlCl4 und anschließender PPh3-Zugabe die Nitrosyl-carbonyl-Komplexe W(NO)(CO)4(AlCl4) und WCl(NO)(CO)2(PPh3)2 darstellen. Sämtliche Nitrosyl-wolfram-Komplexe katalysieren in Kombination mit EtAlCl2 die Metathese von Pent-2-en, jedoch mit deutlich geringerer Aktivität als die entsprechenden Nitrosyl-molybdän-Systeme.
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