Activation of the decomposition of some peroxides with trialkylaluminium compounds under high pressure

Autor: Werner Zeiß, Gerhard Luft, Wolfram Kessler
Rok vydání: 1999
Předmět:
Zdroj: Die Angewandte Makromolekulare Chemie. 269:36-41
ISSN: 1522-9505
0003-3146
DOI: 10.1002/(sici)1522-9505(19990801)269:1<36::aid-apmc36>3.0.co;2-z
Popis: Further investigations were carried out into the activation of the decomposition of organic peroxides. The rate of decomposition of di-tert-butyl peroxide, a standard initiator for the free radical high pressure polymerisation of ethylene, was measured in the presence of triethylaluminium using Raman spectroscopy. The results obtained at pressures of 10 to 1800 bar and temperatures of 85 to 200°C were used to determine the rate constant, the energy of activation and the activation volume as well as the decomposition half-life. In the same way, 2,2-bis(tert-butylperoxy)butane, a bifunctional initiator used only fairly recently in industrial-scale polymerisation, was investigated. The measurements show that not only the decomposition of peroxy esters but also that of dialkyl peroxides and perketals is accelerated by aluminium alkyls. Aluminium alkyls form complexes with the peroxides, radicals being formed during the decomposition of the complexes. These reactions have a substantially lower energy of activation than the decomposition of the pure peroxides. As a result, radical polymerisation reactions can be initiated by using a peroxide/aluminium alkyl system at lower temperatures.
Databáze: OpenAIRE
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