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  • 1
    Electronic Resource
    Electronic Resource
    s.l. : American Chemical Society
    Macromolecules 24 (1991), S. 5040-5045 
    ISSN: 1520-5835
    Source: ACS Legacy Archives
    Topics: Chemistry and Pharmacology , Physics
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 6 (1969), S. 89-100 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: This publication relates to examples of the application of redox resins in organic chemistry. These redox resins contain various quinone/hydroquinone systems. p-Benzoquinone was reduced to hydroquinone and some hydrogenated aromatic and heterocyclic compounds were dehydrogenated to the corresponding aromatic and heterocyclic parent compounds by redox resins. Following the STRECKER degradation α-aminocarboxylic acids were degraded to the corresponding aldehydes having one C-atom less than the α-aminocarboxylic acid. Redox resins can be used as antioxydants as has been shown in the synthesis of 3-acetoindole.
    Notes: Es wird über Anwendungsbeispiele für Redoxharze in der organischen Chemie berichtet, die als Redoxsysteme verschiedene Chinon-Hydrochinon-Systeme enthalten. p-Benzochinon läßt sich zu Hydrochinon reduzieren. Hydroaromaten und Hydroheterocyclen können durch Redoxharze zu den entsprechenden Aromaten bzw. Heterocyclen dehydriert werden. Entsprechend dem STRECKERschen Abbau lassen sich α-Aminocarbonsäuren durch Redoxharze zu dem um ein C-Atom ärmeren Aldehyd abbauen. Anhand der 3-Acetylindoldarstellung wird gezeigt, daß ein Redoxharz als Antioxydans eingestzt werden kann.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Ag, Cu, Te and Se were precipitated from aqueous solutions by a redox resin containing the system anthraquinone/anthrahydroquinone. Ag, Cu and Te were dissolved in 1 N nitric acid. Se was dissolved in a solution of KCN. This resin was able to alter the valences of variable-valence ions (UO22+ → U4+; VO2-2 → V3+). It was possible to produce H2O2 solutions up to a concentration of 1.3 N in a continuous process with a resin made by condensation of hydroquinone and phenol with formaldehyde.
    Notes: Ein das Anthrachinon-Anthrahydrochinon-System enthaltendes Redoxharz wurde zur Abscheidung von Ag, Cu, Te und Se aus wäßriger Lösung eingesetzt. Ag, Cu und Te wurden in 1 n HNO3 und Se in KCN-Lösung gelöst. Mit diesem Harz wurden auch Ionenumladungen (UO2+2 → V4+ und VO-2 → V3+) vorgenommen. Mit einem Kondensationsharz aus Hydrochinon, Phenol und Formaldehyd konnten in einem kontinuierlichen Verfahren bis zu 1,3 n H2O2-Lösungen hergestellt werden.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 29 (1973), S. 307-347 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: In this review article we want to give information about low molecular and polymer organic semiconductors, which were recently synthesized in our institute.Specific electric conductivities up to σ298°K = 9.0 · 10-5Ω-1 · cm-1 and thermic activation energies of E = 0.30 eV of polyenearylenes, respectively -heteroarylenes were measured.Polyazomethines have a maximum σ298°K = 3.3 · 10-9Ω-1 · cm-1 and E = 0.35 eV. Polymers with indophenine units have conductivities up to σ298°K = 1.1 · 10-4Ω-1 · cm-1 and E = 0.39 eV. A maximum of σ298°K = 5.0 · 10-2Ω-1 · cm-1 and E = 0.05 eV was found for bis-(1.2-dicyanoethylenedithiolo)-metal salts.Polymers with a phthalocyanine- or hemiporphyrazine-like structure achieve a conductivity of σ298°K = 2.3 · 10-2Ω-1 · cm-1 and E = 0.15eV. Coordination polymers of dimercaptomaleic acid, respectively their monoamide show a maximum of σ298°K = 3.2 · l0-lΩ-l · cm-1 and E = 0.20 ev. Polymers with σ298°K ≤1.5 · 10-5 Ω-l · cm-l and E ≥ 0.5 eV were obtained by the polymerization of succinonitrile.All the investigated substances show an electronic conductivity. The existence of an ionic conductivity could, in all cases, be excluded by using direct current measurements over a long period of time.
    Notes: In der folgenden zusammenfassenden Darstellung wird über niedermolekulare und polymere organische Halbleiter berichtet, die in letzter Zeit in unserem Institut synthetisiert wurden.Bei den Polyenarylenen bzw.-heteroarylenen werden spezifische elektrische Leitfähigkeiten bis zu σ298°K = 9,0 · 10-5Ω-1 · cm-1 bei einer thermischen Aktivierungsenergie E = 0,30 eV gemessen. Polyazomethine besitzen maximal σ298°K = 3,3 · 10-9Ω-1 · cm-1 bei E = 0,35 eV. Polymere mit Indophenineinheiten haben bis zu σ298°K = 1,1 · 10-4Ω-1 · cm-1 bei E = 0,39 eV. Bei Bis-(1,2-dicyanäthylendithiolo)-metallsalzen wird maximal σ298°K = 5,0 · 10-2Ω-1 · cm-1 bei E = 0,05 eV gefunden. Polymere mit einer phthalocyaninartigen oder hemiporphyrazinartigen Struktur erreichen σ298°K = 2,3 · 10-2Ω-1 · cm-1 bei E = 0,15 eV. Koordinationspolymere aus Dimercaptomaleinsäure bzw. ihrem Monoamid weisen maximal σ298°K = 3,2 · 10-1Ω-1 · cm-1 bei E = 0,20 eV auf. Bei der Polymerisation von Bernsteinsäuredinitril wurden Polymere mit σ298°K≤ 1,5 · 10-5Ω-1 · cm-1 bei E≥0,5 eV erhalten.Alle untersuchten Verbindungen weisen eine elektronische Leitfähigkeit auf. Das Vorhandensein einer Ionenleitfähigkeit konnte in allen Fällen auf Grund von Gleichstromdauermessungen ausgeschlossen werden.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: ß-Hydroxyethyl methacrylate = HEMA has been copolymerized with different crosslinkers and swollen in isotonic NaCl solution resulting in hydrogels. Crosslinking is produced more by the length of the crosslinker than by its hydrophilic character. The water content of hydrogels can be increased weakly, if ethylene glycol or glycerin is added to the polymerization mixture. Hydrogels with up to 70percnt; of water have been prepared from HEMA and dimethylaminoethyl methacrylate = DMAEMA and those with up to 90% of water from HEMA and methacrylic acid = MA. Hydrogels from HEMA, DMAEMA and MA, containing up to 70% of water, are distinguished by a neglegible shrinkage during the change from NaCl to CaCl2 solution as well as by a high oxygen permeation.
    Notes: ß-Hydroxyethylmethacrylat = HEMA wird mit verschiedenen Vernetzern copolymerisiert und in isotonischer NaCl-Lösung zu Hydrogelen gequollen. Es wird gefunden, daß die Vernetzung von der Länge des Vernetzermoleküls stärker abhängt als von seiner Hydrophilie. Der Wassergehalt von Hydrogelen läßt sich geringfügig steigern, wenn dem Polymerisationsansatz Ethylenglykol oder Glycerin zugesetzt wird. Hydrogele mit bis zu 70% Wasser werden aus HEMA und Dimethylaminoethylmethacrylat = DMAEMA und solche mit bis zu 90% Wasser aus HEMA und Methacrylsäure = MA erhalten. Hydrogele aus HEMA, DMAEMA und MA, die einen Wassergehalt von bis zu 70% besitzen, zeichnen sich durch einen vernachlässigbaren Schrumpf beim Wechsel von NaCl- in CaCl2-Lösung sowie eine sehr gute Sauerstoff-Permeation aus.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 6
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 227 (1995), S. 139-157 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Es wurden 12 Bis- und Trismaleimide hergestellt, charakterisiert und ihre Reaktionen mit Polyamiden in der Schmelze untersucht. Es wurde gefunden, daß die Doppelbindungen der Maleimide mit den endständigen Aminogruppen der Polyamide zu elastomeren Netzwerken reagieren. Die chemischen und physikalischen Eigenschaften dieser Elastomeren wurden untersucht. Mischungen aus Bis- und Trismaleimiden mit aminoterminierten Polyamiden können als Schmelzkleber mit hoher Zug- und Scherspannung, guter Thermostabilität und hoher chemischer Beständigkeit eingesetzt werden.
    Notes: 12 bis- and tris(maleimide)s were synthesized and characterized and their reactions with polyamides in the melt were examined. It was found that the double bonds of the maleimides react with terminal amino groups of the polyamides to form elastomeric networks. The chemical and physical properties of these elastomers were examined. Mixtures of bis- and tris(maleimide)s with amino-terminated polyamides can be applied as hot melt adhesives with high tensile and shear strength, with high thermal stability and high chemical resistance.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 228 (1995), S. 59-72 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Description / Table of Contents: Hydrogele (vernetzte Polymere mit einem definierten Wassergehalt) basierend auf 3-O-Acryloyl-1,2;5,6-di-O-isopropyliden-α-D(-)-glucofuranose und 2-Hydroxyethyl-methacrylat wurden durch radikalische Copolymerisation und anschließende saure Hydrolyse der Isopropyliden-Schutzgruppen hergestellt. Die erhaltenen Hydrogelproben wurden auf lineare Quellung, Wassergehalt, Brechungsindex, extrahierbare Bestandteile, Durchlässigkeit sichtbaren Lichtes und Sauerstoffdurchlässigkeit als typische Kontaktlinseneigenschaften untersucht.
    Notes: Hydrogels (crosslinked polymers with a defined water content) based on 3-O-acryloyl-1,2;5,6-di-O-isopropylidene-α-D(-)-glucofuranose and 2-hydroxyethyl methacrylate were prepared by radical copolymerization and acid hydrolysis of the isopropylidene protecting groups. The obtained hydrogel samples were examined for linear expansion to hydration, weight-percent hydration, refractive index, extractables, percent transmission of visible light and oxygen permeability as typical properties for contact lens materials.
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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  • 8
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Angewandte Makromolekulare Chemie 185 (1991), S. 147-154 
    ISSN: 0003-3146
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The electrochemical polymerization of 2,2′-bithienyl (BT) leads to the formation of redox active polymer layers on the anode. The wettability of these poly (2,2′-bithienyl-5,5′diyl) (PBT) layers was studied as a function of the experimental conditions (concentration, current density, film thickness and the potential of the polymer electrode). A drastic change in the wettabilty was observed within the redox process.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 9
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 112 (1979), S. 2342-2346 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Basefree Wittig Reactions with Phase Transfer CatalytsKetones like trifluoroacetyl compounds  -  giving the haloform reaction in basic solutions  -  are able to react with mono or bis phosphonium fluorides without bases via Wittig reactions with very good yields. The phosphonium fluorides are prepared very easily from other phosphonium halides under phase transfer catalysis of crown ethers. The ratio of the stereoisomeric alkenes in the product and the spectra of the trans- respectively trans-trans alkenes are given.
    Additional Material: 2 Tab.
    Type of Medium: Electronic Resource
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  • 10
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Berichte der deutschen chemischen Gesellschaft 113 (1980), S. 3384-3388 
    ISSN: 0009-2940
    Keywords: Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Synthesis and X-Ray Structure of (E)-α-(Trifluoromethyl)stilbeneStarting from benzyltriphenylphosphonium chloride and ω,ω,ω-trifluoroacetophenone α-(trifluoromethyl)stilbene was prepared with 91% yield with a phase transfer-catalyzed Wittig reaction with solid KF but without bases. The isolated isomer was found by X-ray structure analysis to have the thermodynamic preferred (E)-configuration. For this configuration it was determined a torsion angle of 71.3° between the two cis-configurated phenyl rings because of steric hindrance. AH⃜F hydrogen bridge (distance: 223.8 pm) stabilizes the (E)-isomer.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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