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  • 1
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    Hydride transfer to stable carbenium salts (1983)
    Springer
    Details
    Publication Date: 1983-01-01
    Print ISSN: 0170-0839
    Electronic ISSN: 1436-2449
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Published by Springer
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  • 2
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    Kinetik der Styrolpolymerisation mit BF3.(C2H5)20 in Gegenwart von π-Elektronen-Acceptoren (1977)
    Springer
    Details
    Publication Date: 1977-08-01
    Print ISSN: 0372-820X
    Electronic ISSN: 1435-1536
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Published by Springer
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  • 3
    Electronic Resource
    Electronic Resource
    Separation and characterization of ɛ-caprolactone oligomers by gel permeation chromatography (1985)
    Springer
    Polymer bulletin 13 (1985), S. 285-291 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary It is shown that the combined use of gel permeation chromatography and the isocyanate method of determination of hydroxyl end groups extends the possibilities for studying complex oligomer mixtures of ɛ-caprolactone. Oligomer mixtures of ɛ-caprolactone obtained by (C6H5)3CSbCl6 and by (C6H5)3CK are investigated. At initiation by both the initiators — the cationic and the anionic one — a covalent bond between the initiator and the polymer chain is formed. In the case of the initiation by (C6H5)3CK intramolecular transesterification proceeds which results in cyclic oligomers. At initiation by (C6H5)3CSbCl6 linear oligomers are formed. It is assumed that the ɛ-caprolactone polymerization by (C6H5)3CSbCl6 proceeds by alkyl-oxygen bond scission.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00254664
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  • 4
    Electronic Resource
    Electronic Resource
    Hydride transfer to stable carbenium salts (1983)
    Springer
    Polymer bulletin 10 (1983), S. 411-413 
    Details
    ISSN: 1436-2449
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Summary The interaction between (C6H5)3CSbCl6, (C6H5)2CHSbCl6, (ClC6H4)3CSbCl6 and poly(ɛ-caprolactone), dimers of α-methyl-styrene and of 1,1-diphenylethylene is investigated. By the use of 1H-NMR spectroscopy it is found that hydride transfer proceeds to the stable salts.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00262182
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  • 5
    Electronic Resource
    Electronic Resource
    Kinetik der Styrolpolymerisation mit BF3.(C2H5)20 in Gegenwart von π-Elektronen-Acceptoren (1977)
    Springer
    Colloid & polymer science 255 (1977), S. 809-809 
    Details
    ISSN: 1435-1536
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01664467
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  • 6
    Electronic Resource
    Electronic Resource
    Some principles of the chemical destruction of polyarylates (1968)
    Springer
    Russian chemical bulletin 17 (1968), S. 1406-1411 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The chemical destruction of poly-9, 9-bis-(4-hydroxyphenyl)fluorene terephthalate under the action of hexanediol, p-xylylene glycol, 9, 9-bis-(4-hydroxyphenyl)fluorene, terephthalyl chloride, and adipic and isophthalic acids was investigated. 2. Despite the high chemical stability of polyarylates under conditions corresponding to their synthesis, they are subject to alcoholysis, phenolysis, acidolysis, and exchange at the expense of the acid chloride function. 3. The rate and degree of destruction of the polarylate are determined by the nucleophilicity of the attacking agent. 4. The catalytic action of hydrogen chloride is manifested in all types of destructive processes that occur during the synthesis of polyarylates by high-temperature polycondensation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00907834
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  • 7
    Electronic Resource
    Electronic Resource
    Mechanism of the polycondensation of polycyclic bis-phenols with chlorides of aromatic dicarboxylic acids (1970)
    Springer
    Russian chemical bulletin 19 (1970), S. 771-775 
    Details
    ISSN: 1573-9171
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Conclusions 1. The kinetics of the polycondensation of chlorides of aromatic dicarboxylic acids with polycyclic bis-phenols, containing norbornane groups at the central carbon atom, were studied in ditolylmethane solution in the temperature interval 150–200°. 2. The reaction of terephthalyl chloride with 4,4′-(hexahydro-4,7-methylenindan-5-ylidine)diphenol is first order with respect to the bis-phenol and half order with respect to the acid chloride. 3. During the reaction, at high degrees of conversion in the interaction of other polycyclic bis-phenols with terephthalyl chloride, one and a half order of the reaction is preserved. 4. The mechanism of the formation of polyarylates of polycyclic bis-phenols differs from bimolecular. It is proposed that the reaction proceeds according to an ionic mechanism, and a kinetic scheme is proposed for the process. 5. The values of the effective rate constants at various temperatures and the parameters of the Arrhenius equation were determined.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00867231
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  • 8
    Electronic Resource
    Electronic Resource
    Alkali metal solutions in organic solvents obtained in the presence of polyethylene oxide (1970)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 134 (1970), S. 313-316 
    Details
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Alkali metals dissolve not only in liquid ammonia but also in ethers, such as tetrahydrofuran (THF), 1.2-dimethoxyethane (DME), and dimethyl ether of diethylene glycol (diglyme), blue solutions being obtained1,2. “Blue” solutions can be obtained only with rigorously purified reagents in full absence of moisture and oxygen, usually at low temperature. They are not very stable systems, especially at room temp., and discoloration begins shortly after the removal of the metal. The concn. of the metal dissolved is as low as 10-4 to 10-3 mole/1. The electrical conductivity of the “blue” solutions is in the range of 10-5 to 10-6 ohm-1 cm-1 and that of the discolored solution is 10-8 to 10-9 ohm-1 cm-1.Obviously the solvation ability of the solvent plays a very important role in the formation of metal solutions. DAINTON et al.1,3 presented arguments that the predominant species in the “blue” solutions are pairs of electrons (e2) with coupled spins, whereas TUTTLE and WEISSMAN4 observed at -80°C a weak singlet in the ESR spectrum of the potassium solution in DME, and CAFASSO and SUNDHEIM2 revealed a weak ESR signal in a rubidium solution in bis-2-(2-methoxyethoxy) ethyl ether as well as in a frozen potassium solution in DME.“Blue” alkali metal solutions can be easily obtained in hexamethylphosphoramide but it is not still clear whether they are solutions of alkali metals5 or of anion-radicals of the solvent6.It was established that potassium solutions in THF and DME initiated polymerization of acrylonitrile (conversion about 4%) and of styrene (conversion up to 100%), but not of methyl methacrylate and acrylamide3.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1970.021340129
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  • 9
    Electronic Resource
    Electronic Resource
    Kinetics of styrene polymerization initiated by boron trifluoride diethyl etherate in the presence of π-electron acceptors (1975)
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 176 (1975), S. 947-962 
    Details
    ISSN: 0025-116X
    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 durch Bortrifluoriddiäthylätherat (1) in Gegenwart von Tetracyanoäthylen (2) oder 1,3,5-Trinitrobenzol (3) initiierten Styrolpolymerisation in 1,2-Dichloräthan wurde untersucht. Es wurde festgestellt, daß die Reaktion in bezug auf das Monomere zweiter Ordnung und in bezug auf den Katalysator erster Ordnung ist. Durch Zugabe der π-Elektronen-Acceptoren 2 oder 3 erhöhte sich die Polymerisationsgeschwindigkeit, ohne daß sich dabei die Konzentrationsabhängigkeiten änderten. In Gegenwart von 2 erniedrigte sich die Aktivierungsenergie von 11,4 kcal/mol (47,7 kJ/mol) auf 6,9 kcal/mol (28,8 kJ/mol). Weiterhin wurde der Zerfall des Styrols/2-Komplexes in Gegenwart von 1 nachgewiesen. Die Kinetik und die Leitfahigkeitsmessungen zeigen, daß die Erhöhung der Polymerisationsgeschwindigkeit bei Zugabe der Acceptoren 2 (oder 3) wahrscheinlich hauptsächlich durch eine Steigerung der Konzentration der freien Ionen verursacht wird.
    Notes: The kinetics of the polymerization of styrene in 1,2-dichloroethane, initiated by boron fluoride diethyl etherate (1), was studied in the presence of small amounts of tetracyanoethylene (2) or 1,3,5-trinitrobenzene (3). The reactions are of second order with respect to the monomer and of first order with respect to the catalyst. Addition of the π-electron acceptors 2 or 3 increased the polymerization rate without affecting the concentration-dependences of the system. In the presence of 2 the activation energy decreased from 11,4 kcal/mol (47,7 kJ/mol) to 6,9 kcal/mol (28,8 kJ/mol). The decomposition of the styrene/2-complex in the presence of 1 was demonstrated. The results from the kinetic and conductometric measurements showed that the increase in the polymerization rate at the addition of the acceptors 2 (or 3) was probably mainly due to an increase of the concentration of free ions.
    Additional Material: 13 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/macp.1975.021760410
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  • 10
    Electronic Resource
    Electronic Resource
    Characteristics and initiation ability of 9-anthranylmethyl hexafluorophosphate (1986)
    Bognor Regis [u.a.] : Wiley-Blackwell
    Journal of Polymer Science Part A: Polymer Chemistry 24 (1986), S. 3271-3277 
    Details
    ISSN: 0887-624X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: 9-Anthranylmethyl hexafluorophosphate-a stable primary carbenium salt-is prepared and characterized by UV, VIS, and NMR spectroscopy and by conductometric measurements in methylene chloride. 9-Anthranylmethyl hexafluorophosphate initiates the polymerization of vinyl and heterocyclic monomers. This initiator has higher reactivity than trityl and diphenylmethyl salts. The initiation mechanism of the polymerization of some monomers is investigated.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pola.1986.080241211
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