The effect of titanium compounds on photo-oxidation of 2,4,6,8-tetramethylnonane (a liquid model of polypropylene)

✍ Scribed by O. Cicchetti; F. Gratani

• Publisher: Elsevier Science
• Year: 1972
• Tongue: English
• Weight: 651 KB
• Volume: 8
• Category: Article
• ISSN: 0014-3057
• DOI: 10.1016/0014-3057(72)90133-4

✦ Synopsis

Ala~raet--The main study was of the effect of n-butyl orthotitanate as a photo-initiator in the oxidation at 34" 5 ° of 2,4,6,8-tetramethylnonane (a liquid model for polypropylene) irradiated by u.v. light having, in the region 2900-3500 A, a spectral distribution similar to that of the solar radiations reaching the Earth's surface, n-Butyl orthotitanate was chosen as a model for Ti(IV) compounds, left in polypropylcne as catalyst residues after purification.

It has been possible to establish that, at least for the conditions studied, 7 per cent of the photoexcited molecules of n-butyl orthotitanate undergo homolytic decomposition with generation of two butoxy radicals. 12 per cent of the butoxy radicals extract a tertiary hydrogen from the hydrocarbon, thus giving alkyl radicals which in turn start the auto-oxidation.

Equations have been obtained giving the values of the overall oxidation rate of the hydrocarbon vs. the irradiation intensity and the concentration of the chromophore.