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  • 1
    Electronic Resource
    Electronic Resource
    Weinheim : Wiley-Blackwell
    Chemie Ingenieur Technik - CIT 67 (1995), S. 1472-1476 
    ISSN: 0009-286X
    Keywords: Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Process Engineering, Biotechnology, Nutrition Technology
    Additional Material: 8 Ill.
    Type of Medium: Electronic Resource
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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: The kinetics of the autoxidation of 2,3-dimethylbutadiene (1,3) yielding polymeric peroxides have been investigated and compared with the spontaneous autoxidation of the Me-ester of 10,12-octadecadienoic acid. Both reactions are shown to be of autocatalytical character: the rate of autoxidation is proportional to the square root of mole O2/mole diene. The peroxides split into radicals starting autoxidation chains in a monomolecular manner. The energies activation have been determined.The influences of azoisobutyronitrile, ascaridole, di-tert. -butylperoxide and copper salt of α-ethylcaproic acid on the autoxidation of the Me-ester of 10,12-octadecadienoic acid have been investigated. The result of all is that polymeric peroxides are formed.
    Notes: Die spontane Autoxydation des Dimethylbutadiens, die zu polymeren Peroxyden führt, wird kinetische verfolgt und mit der Autoxydation des konjugierten 10, 12-Octadecadiensäuremethylesters verglichen. Beide Reaktionen verlaufen autokatalytisch. Die Reaktionsgeschwindigkeit ist zu Beginn der Wurzel aus dem Autoxydationsgrad (Mol O2/Mol Substrat) proportional. Die gebildeten Peroxyde zerfallen monomolekular in kettenstartende Radikale. Die Brutto-aktivierungsenergieen werden angegeben.Die Einwirkung von Azodiisobuttersäurenitril, Ascaridol, Di-tert.-Butylperoxyd und Cu++ -oktoat auf die Autoxydation des 10,12-Octadecadiensäuremethylesters wird untersucht. Es ergibt sich, daß auch die Autoxydation des konjugiert-ungesättigten Fettsäure-esters zu polymeren Peroxyden führt.
    Additional Material: 9 Ill.
    Type of Medium: Electronic Resource
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  • 3
    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: The polymeric peroxides of dimethylbutadiene, isoprene and cyclopentadiene are thermally decomposed and the fragments analyzed. The content of 1,2-structure of the polymeric peroxide of dimethyl-butadiene is about 40-50%, of the polymeric peroxides of isoprene nearly 25%. The polymeric peroxide of cyclopentadiene has only 1,4-structure.The reaction of the polymeric peroxides with perbenzoic acid had been investigated. The presence of peroxy groups in α-position to an ethylenic bond changes their reactivity with perbenzoic acid, decreasing the reactivity of internal double bonds.
    Notes: Die polymeren Peroxyde von Dimethylbutadien, Isopren und Cyclopentadien werden thermisch zersetzt und die erhaltenen Bruchstücke untersucht. Quantitative Bestimmungen von Formaldehyde ergeben, daß das polymere Dimethylbutadienperoxyd zu 40 bis 50%, das polymere Isopreperoxyd zu etwa 25% aus 1,2-Copolymerisaten der Diene mit molekularem Sauerstoff bestehen. Das polymere Cyclopentadienperoxyd entsteht dagegen anscheinend nur durch 1,4-Addition, da der Nachweis des für ein 1,2-Copolymerisat als Zersetzungsprodukt zu erwartenden Glutaconsäuredialdehyds nicht gelang.Es wird außerdem versucht, mit Perbenzoesäure die bei 1,4-Autoxydation zu erwar-tenden kettenständigen Doppelbindungen neben den bei 1,2-Autoxydation zu erwarten-den Vinylseitenketten zu bestimmen. Die Anwesenheit einer peroxydischen Gruppe in α-Stellung zu einer Doppelbindung ändert deren Reaktionsfähigkeit mit der Persäure; sie ist bei kettenständigen Doppelbindungen vermindert.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    New York : Wiley-Blackwell
    Die Makromolekulare Chemie 18 (1956), S. 406-413 
    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: The Me-ester of 9,11-octadecadienoic acid reacts in 1.2 and 1.4-position with moleculare oxygen to give relatively low molecular oxygen-copolymers. These polymeric peroxides produce autocatalyzing effects in the authoxidation reaction. They are rather resistent and can be stored without showing formation of aldehydes. The reaction of perbenzoic acid with external and internal double bounde standing in α-position to peroxy groups was studied at the examples of allyl-tert.-butyl peroxide and cyclohexenylmethyl peroxide.
    Notes: 9,11-Octadecadiensäuremethylester reagiert mit molekularem Sauerstoff in 1,2- und 1,4-Stellung unter Bildung von relative niedermolekularen Sauerstoff-Copolymerisation. Diese polymeren Peroxyde sind bei der Authoxydation autokatalytisch wirksam. Sie sind recht beständig; die buldung von Aldehyden wurde dei der Aufbewahrung nicht beobachtet. Die Reaktion von end- und von kettenständigen Doppelbindungen, die in Nachbarschaft zu Peroxygruppen stechen, mit Perbenzoesäure wird am Beispiel des Allyl-tert.-Butyl- und des Cyclohexenylmethylperoxyds untersucht.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
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  • 5
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The EI induced fragmentation pathways of 4,5-bis(dimethylamino)fluorene, 4-(d6-dimethylamino)-5-(dimethylamino)fluorene, 4,5-bis(d6-dimethylamino)fluorene, 4-(dimethylamino)-5-methylaminofluorene, 4,5-bis-(methylamino)fluorene, 4-amino-5-methylaminofluorene, 1,8-bis(dimethylamino)naphthalene, 1,8-bis(d6-dimethyl-amino)-naphthalene and 1,8-bis(dimethylamino)-2,7-dimethoxynaphthalene were investigated. A mechanism is pro-posed for the surprising elimination of CH3—NH2 from the molecular ion, followed by loss of C2H5·, C2H4 and CH3CN and for the accompanying cyclizations to stable heterocyclic ions: prior to fragmentation the molecular radical ion rearranges to new, distonic radical ions by reciprocal H and CH3 transfers between the adjacent dimethylamino groups. Each of these new, isomeric molecular ions decomposes subsequently in a characteristic way.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 6
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
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  • 7
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: For four isomeric bis(methoxycarbonyl)[2.2](2,5)pyridinophanes differing only in the mutual orientation of the two nicotinic ester units, electron impact mass spectra were measured. The fragmentations observed distinguish surprisingly well between the isomers, depending on the transannular substitution pattern. Of special interest is that for one isomer the otherwise unimportant ion at m/z 298 is found as base peak. This ion is formed by expulsion of HCN from the molecular ion, transannular cycloaddition and aromatization to a stable quinolizinium ion. Fragmentation pathways of the isomers are compared, and chemical ionization and negative ion chemical ionization mass spectra are discussed.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 8
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The liquid secondary ion mass spectrometry and electron impact ionization fragmentation pathways of 1,9-bis(dimethylamino)-2,8-dimethoxy-dibenzofuran (1), a new proton-sponge base with increased steric compression (buttressing) and much higher basicity (pKa = 14.3), and of its monoprotonated (2) and monodeuterated (3) salts were invetigated in a collision-induced dissociation (CID) tandem mass spectrometric study supported by unimolecular linked scans at constant B/E, CID mass-analysed ion kinetic energy spectra and accurate mass measurements. They show an ‘extended’ proximity effect, involving the stepwise participation of all the four functional groups, in addition to the ‘normal’ proximity effect involving loss of Me2NH and H·. The behaviour of 1 appears to differ in some ways from that of its protonated (2) or deuterated (3) salts. The unprecedented observation of the maintenance of the hydrogen (or deuterium) bridge under soft ionization in the salts of very strong proton-sponge bases, which show buttressing effects in solution, is strong experimental support for the conservation of these buttressing effects in the gas phase, where the protonated (or deuterated) cations of salts such as 2 (or 3) are very stable, H+ (or D+) being completely ‘sequestered.’
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
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  • 9
    ISSN: 0030-493X
    Keywords: Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The electron impact (EI) ionization-induced fragmentation pathways of the new 1,9-bis(dimethylamino) phenalenium cation [1]+ were investigated. The peri-dimethylamino substituents of [1]+ are incorporated in a trimethine cyanine substructure and show strong steric interactions. A mechanism is proposed for the unusual elimination of CH3N=CH2, HN(CH3)2 and (CH3)3N from [1]+ and for the accompanying cyclizations to heterocyclic ions: prior to fragmentation, the intact cation [1]+ rearranges, by reciprocal CH3 and H transfers, to new isomeric cations which decompose subsequently in a characteristic way. A wealth of consistent information on dissociation pathways and fragment structures is provided by collision-induced dissociation tandem mass spectra, collision-induced dissociation mass-analysed ion kinetic energy spectra and exact mass measurements of the salt cation and of its primary fragment ions. The liquid secondary ion mass spectrum of [1]+ is very similar to its EI mass spectrum.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 10
    ISSN: 0749-1581
    Keywords: 4,7-Dichloro-5,8,12,15-tetramethoxy-13,16-bis[4-(2-methoxycarbonylphenyl) butyl][2.2]paracyclophane ; Stereochemistry ; 1H/13C inversely correlated NMR ; Bridge proton coupling constants ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The relative orientation of substituents in the opposite rings of one of the isomeric 4,7-Dichloro-5,8,12,15-tetramethoxy-13,6-bis[4-(2-methoxycarbonylphenyl) butyl][2.2]paracyclophanes was determined by establishing by NOE their orientation relative to the bridge protons, which thus served as ‘space-spy nuclei’. The mutual orientation of these bridge protons was ascertained by the analysis of their coupling constants, obtained from a phasesensitive COSY spectrum. The 1H and 13C resonances were assigned with the aid of 1H COSY and 1H/13C inversely correlated spectra.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
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