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  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 114 (1983), S. 937-951 
    ISSN: 1434-4475
    Keywords: Benzotriazolization of phenols ; 2(2-Hydroxyphenyl)2H-benzotriazole ; Ultraviolet absorbers ; Ultraviolet stabilizers
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Abstract Es wurden einige 2(2-Hydroxyphenyl)2H-benzotriazole mit mehr als einer Benzotriazolgruppe am Di- bzw. Trihydroxybenzol mittels Azokupplung vono-Nitrobenzoldiazoniumchlorid mit Resorcin bzw. Phloroglucin und nachfolgender reduktiver Cyclisierung mit Zn-Pulver/NaOH hergestellt. Durch sorgfältige Kupplung mito-Nitrobenzoldiazoniumchlorid konnte die Monobenzotriazylverbindung hergestellt werden: 4(2H-benzotriazol-2-yl)-1,3-dihydroxybenzol [2(2,4-Dihydroxyphenyl)2H-benzotriazol]. Alle Verbindungen haben unge-wöhnliche UV-VIS-spektroskopische Eigenschaften mit sehr hohen Extinktionskoeffizienten und einem starken Abfall der Adsorption bei 400 nm; es sollte sich um ausgezeichnete UV-Stabilisatoren handeln.
    Notes: Abstract Several 2(2-hydroxyphenyl)2H-benzotriazoles with more than one benzotriazole group substituted on di- and trihydroxybenzenes were synthesized by azo coupling ofo-nitrobenzenediazonium chloride with resorcinol or phloroglucinol followed by reductive cyclization with zinc powder and sodium hydroxide. By careful diazonium coupling witho-nitrobenzenediazonium chloride, the monobenzotriazyl compound, 4(2H-benzotriazole-2-yl)1,3-dihydroxybenzene [2(2,4-dihydroxyphenyl)2H-benzotriazole] was obtained. All compounds have unusual spectral characteristics with high extinction coefficients, cut off of the absorption below 400 nm and are excellent candidates for ultraviolet stabilizers.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1434-4475
    Keywords: 2(2-Hydroxyphenyl)2H-benzotriazole ; Polymerizable stabilizers ; Ultraviolet spectra
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Zusammenfassung 2(2,4-Dihydroxyphenyl)2H-benzotriazol wurde mit 50% Ausbeute über die Kondensation vono-Nitrobenzoldiazoniumchlorid mit Resorcin, gefolgt von reduktiver Cyclisierung der ursprünglich erhaltenen Azoverbindung mit Zn/NaOH, erhalten. Die Kondensation des Diazonium-Salzes hatte unter sorgfältig kontrollierten Bedingungen und im sauren Medium zu erfolgen, da ansonsten „Bis“-Kondensation auftrat, die nach der reduktiven Cyclisierung 2(2,4-Dihydroxyphenyl)1,3-2H-dibenzotriazol ergab. 2(2,4-Dihydroxyphenyl)2H-benzotriazol wurde mit Acryoyl- bzw. Methacryloylchlorid zur Reaktion gebracht, wobei die Monoacetylierungsprodukte in über 60% Ausbeute gewonnen wurden. Die beiden Monomeren wurden homopolymerisiert und mit Styrol, Methylmethacrylat undn-Butylacrylat zu Polymeren hohen Molekulargewichts copolymerisiert. Die Inkorporierung von 2[2-Hydroxy-4-acryloxy (bzw. 4-methacryloxy)]2H-benzotriazol in das Copolymer erfolgte zwischen 1 und 10 mol% der Comonomer-Mischung. Die UV-Spektren der Monomeren, Homo- und Copolymeren sind angegeben.
    Notes: Abstract 2(2,4-Dihydroxyphenyl)2H-benzotriazole has been prepared in about 50% yield by condensation ofo-nitrobenzenediazonium chloride with resorcinol followed by reductive cyclization of the initially obtained azo compound with zinc and sodium hydroxide. The condensation of the diazonium salt had to be carried out under carefully controlled conditions and in acidic medium, otherwise “bis”-condensation occurred which, after reductive cyclization, yielded 2(2,4-dihydroxyphenyl)1,3-2H-dibenzotriazole. 2(2,4-Dihydroxyphenyl)2H-benzotriazole was allowed to react with acryloyl or methacryloyl chloride. Monoacylation in the 4-position occurred by interfacial acylation technique and 2[2-hydroxy-4-acryloxy (or 4-methacryloxy)]2H-benzotriazole was obtained in over 60% yield. The two monomers were homopolymerized and copolymerized with styrene, methyl methacrylate, andn-butyl acrylate to polymers of high molecular weight. Incorporation of 2[2-hydroxy-4-acryloxy (or 4-methacryloxy)]2H-benzotriazole into the copolymer was from 1 to 10 mol% of the comonomer mixture. The ultraviolet spectra of monomers, homo- and copolymers were also determined.
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Stamford, Conn. [u.a.] : Wiley-Blackwell
    Polymer Engineering and Science 23 (1983), S. 597-600 
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Head-to-head polyisobutylene, prepared by the Grignard coupling reaction of 2,2,3,3-tetramethyl-1,4-dibromobutane had molecular weight of 3,000 to 10,000 and was characterized by wide angle x-ray diffraction, optical microscopy and thermal behavior. Head-to-head polyisobutylene is crystalline, with a crystalline melting point of 187°C and a glass transition temperature of 87°C (measured by DSC at a scan rate of 20°/min.); these values compare to a glass transition temperature of head-to-tail polyisobutylene of similar molecular weight of -61°C and a crystalline melting point of 5°C, which can only be observed when the sample was stretched. The maximum rate of degradation of head-to-head polyisobutylene (20°/min. programmed temperature increase) is at 315°C, 70°C lower than that of head-to-tail polyisobutylene.
    Additional Material: 6 Ill.
    Type of Medium: Electronic Resource
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  • 4
    ISSN: 0032-3888
    Keywords: Chemistry ; Chemical Engineering
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Homopolymers of 2,6-dimethylphenyl 10-undecenoate and copolymers of 2,6-dimethylphenyl 10-undecenoate with α-olefins, prepared by coordination initiators using aluminum activated titanium trichloride, and the corresponding sodium carboxylate and carboxylic acid derivatives have been characterized. IR and NMR investigations gave the normal; spectral characteristics typical for estersubstituted polyolefins and their derivatives. The thermal behavior of the polymeric esters, investigated by differential scanning calorimetry, showed glass transitions characteristic of poly(α-olefins). Polymeric acids and salts presented quite different behavior; most notably the polymeric salt showed no glass transition, but rather an exothermic transition, resembling a broad melting peak at 250-270°C, which is characteristic of a crystalline polymer. We interpret this behavior as the melting of carboxylate cluster domains, which according to our WAXD analysis has a domain size of about 25 Å.
    Additional Material: 7 Ill.
    Type of Medium: Electronic Resource
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