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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 115 (1984), S. 205-214 
    ISSN: 1434-4475
    Keywords: Crown ether ; Phasetransfer catalyst
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung Synthesen cyclischer Carbonate2 durch Umsetzung von CO2 mit Oxiranen1 in Gegenwart von Alkalimetall-Phasentransfer-Katalysatoren werden beschrieben. Ein möglicher Reaktionsmechanismus wird vorgeschlagen.
    Notes: Abstract The synthesis of cyclic carbonates2 by reaction of carbon dioxide with oxiranes1 in the presence of alkali metal salt-phase-transfer agent catalysts is reported. A reaction mechanism is proposed.
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  • 2
    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: Es wurden Untersuchungen über die Reaktion von Diäthylzink (1) mit Resorcin (2) und Phloroglucin (8) bei verschiedenen Molverhältnissen durchgeführt. Dabei wurde gefunden, daß die Reaktion von 1 mit 2 beim Molverhältnis 1:1 in zwei Stufen verläuft. Im ersten Schritt reagiert 1 sehr schnell mit der halben Menge des eingesetzten Resorcins zum Di(äthylzink)resorcinolat (6), das dann langsam mit dem noch vorhandenen Resorcin reagiert. Das im zweiten Schritt entstandene Zink-(3-äthylzinkoxyphenolat)resorcinolat (5) ist ein aktiver Katalysator für die Copolymerisation von Kohlendioxid mit Propylenoxid. Ähnlich verläuft die Reaktion von 1 mit 8.
    Notes: Investigations on the reactions of diethylzinc (1) with resorcinol (2) and phloroglucinol (8) were carried out for different mole ratios of the reactants. It was found that the reaction of 1 with 2 at a mole ratio of 1:1 is a two step process. In the first step 1 reacts very rapidly with half of applied 2 yielding di(ethylzinc) resorcinolate (6), which then reacts slowly with the remaining amount of 2. It was found that zinc 3-ethylzincoxyphenolate resorcinolate (5) formed in the second step is an active catalyst of the copolymerization reaction of carbon dioxide with propylene oxide. The reaction of 1 with 8 shows a similar course.
    Additional Material: 3 Ill.
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  • 3
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 177 (1976), S. 1293-1299 
    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: Es wurde die Copolymerisation von Acrylnitril (AN), Methacrylnitril (MAN), Methylacrylat (MA) und Methylmethacrylat (MMA) mit Butadien (BD) in Gegenwart von Aluminiumäthyldichlorid, Zinkchlorid und Zinnchlorid untersucht. Die Reaktivität der polaren Monomere bei der Copolymerisation nimmt in folgender Reihe ab: AN〉MAN〉MMA〉MA. Es wurde festgestellt, daß AN und MAN mit BD Copolymere bilden, deren Zusammensetzung 1:1 beträgt; MMA und besonders MA bilden jedoch mit BD Copolymere, deren Zusammensetzung sich von dem Molverhältnis 1:1 unterscheidet.Als eine Konkurrenzreaktion der Copolymerisation in den untersuchten Systemen wurde die Diels-Alder-Reaktion nachgewiesen. Die Reaktivität der polaren Monomere in der Diels-Alder-Reaktion nimmt in folgender Reihe zu: MAN〈AN〈MMA〈MA. In Gegenwart von Aluminiumbromid und Antimonchlorid bilden diese Monomere mit BD entsprechende Diels-Alder-Addukte aber nicht die Copolymere.Die erhaltenen Ergebnisse werden mit Hilfe der Elektronenakzeptor-Eigenschaften der polaren Vinylmonomeren und der Stabilität der Charge-Transfer-übergangskomplexe zwischen den zur Copolymerisation und Diels-Alder-Reaktion eingesetzten Monomeren diskutiert.
    Notes: The copolymerization of acrylonitrile (AN), methacrylonitrile (MAN), methyl acrylate (MA), and methyl methacrylate (MMA) with butadiene (BD) in the presence of ethylaluminium dichloride, zinc chloride, and stannic chloride was investigated. The reactivity of polar monomers in the copolymerization was found to decrease in the following order: AN〉MAN〉MMA〉MA. It was also found that AN and MAN form with BD copolymers of essentially 1:1 composition; MMA, and particularly MA were found, however, to form with BD copolymers of a composition different from 1:1.In competition with the copolymerization, a Diels-Alder reaction was shown to occur in the investigated systems. The reactivity of polar monomers in the Diels-Alder reaction was found to increase in the following order: MAN〈AN〈MMA〈MA. In the presence of aluminium bromide and of antimony chloride these monomers were found to produce with BD the corresponding Diels-Alder adducts but not the copolymers.The obtained results are discussed in terms of the electron-accepting properties of polar vinyl monomers and of the stability of transient charge-transfer complexes between the monomers involved in the copolymerization and the Diels-Alder reaction.
    Additional Material: 1 Tab.
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 47-54 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of new catalytic systems: (C2H5)2Zn/polyhydric phenols was prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide (epoxypropane) was studied. On the basis of the results obtained, the structure of organozinc compounds formed in these systems and also in others described in the literature is proposed and discussed. It is shown that the presence of an internal coordinative bond in the catalyst molecule is responsible for its activity in copolymerization.
    Additional Material: 1 Tab.
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  • 5
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Acrylonitrile (AN) and butadiene (BD) were copolymerized in the presence of binary C2H5AlCl2—MtXn (MtXn = metal halide or metal alkoxide) and ternary ZnCl2—RmMtXn—VOCl3 (RmMtXn = metal alkyl or alkylmetal chloride) catalytic systems. The yield of the copolymer (mole ratio of units AN/BD = 1:1) formed in the presence of the above systems, and the effects of the molar proportion of catalyst components, of the reaction temperature and time on the copolymer yield in some systems were determined. The role of individual components of binary and ternary catalytic systems in the copolymerization is discussed.
    Additional Material: 2 Ill.
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  • 6
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 179 (1978), S. 2545-2548 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Additional Material: 1 Ill.
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  • 7
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 178 (1977), S. 1873-1879 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Terpolymerizations of polar vinyl monomers, acrylonitrile, methyl acrylate, or methyl methacrylate with butadiene and styrene in the presence of ethylaluminium dichloride, zinc chloride, or other Lewis acids were carried out. The yield and the contents in monomer units of the terpolymer and the yields of the polar vinyl monomer/butadiene 1,4-cycloaddition byproduct formed in these systems were determined. Butadiene conversions in the above terpolymerizations and 1,4-cycloaddition side reactions were related to those in the copolymerization and 1,4-cycloaddition proceeding in corresponding binary systems without styrene. The results are discussed in terms of a radical polymerization and a polar 1,4-cycloaddition mechanisms.
    Additional Material: 2 Ill.
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  • 8
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: A series of new catalytic systems ZnEt2/cocatalyst were prepared and their activity in the alternating copolymerization of carbon dioxide with propylene oxide was studied. The systems ZnEt2/m-HXC6H4XH (mole ratio 1:1) system (X = NH, S) were chosen to elucidate the influence of the heteroatom on the activity of the catalytic system. The obtained results were discussed in terms of the influence of the basicity of the heteroatom and of its hybridization on the structure and association of the catalyst molecule.
    Additional Material: 2 Tab.
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  • 9
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: Carbon dioxide was copolymerized with propylene oxide (PO, 2-methyloxirane) in the presence of a catalyst system based on alkylmetal compounds (MtRn, Mt = Zn, Cd, Al) and pyrogallol (PG) at mole ratios 1:1, 2:1, and 3:1, respectively. The reaction was found to produce an alternating copolymer poly(propylene carbonate), [poly(oxycarbonyloxypropylene)], using Zn and Cd containing catalysts and non-alternating copolymers with Al containing catalysts. For the system ZnR2/PG (mole ratio 2 : 1), the most active system, the influence of substituents R at the zinc atom, as well as effects of solvents and complexing agents on the copolymer yield and intrinsic viscosity were investigated. The results are discussed in terms of an anionic coordinative copolymerization mechanism.
    Additional Material: 1 Ill.
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  • 10
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 183 (1982), S. 1081-1091 
    ISSN: 0025-116X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Physics
    Notes: The copolymerization of methyl acrylate (MA) and isobutylene (IB) in the presence of Lewis acids (EtAlCl2, Et2AlCl, Et3Al, AlCl3, and ZnCl2) at low Lewis acid/MA mole ratio was investigated. EtAlCl2 and Et2AlCl were found to initiate the spontaneous reaction. An alternating copolymer was produced in this reaction when an excess of IB in the initial monomer feed was used. The copolymerization in the presence of Et3Al, AlCl3, and ZnCl2 did not proceed spontaneously and was initiated by dibenzoyl peroxide (BPO). In this case MA-rich copolymers are formed even in systems containing a large excess of IB in the monomer feed. The addition of BPO to systems containing ethylaluminium chlorides strongly diminishes the tendency towards alternating propagation. It was concluded that the mode of initiation has a significant influence on the copolymer composition. The alternating copolymerization by EtAlCl2 was studied in detail in order to determine the influence of the catalyst concentration, monomer feed ratio, reaction temperature and time on the monomer conversion, copolymer composition, molecular weight and tacticity.
    Additional Material: 2 Ill.
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