| Abstract: | The effect of some alkyl halides (tert-butyl fluoride, butyl fluoride, benzyl fluoride, benzyl chloride and benzyl bromide) on the polymerization of isobutene in heptane catalyzed with Ti(IV) halides was investigated. It was found that additions of tert-butyl fluoride and benzyl fluoride to a solution of isobutene and titanium(IV) chloride, bromide or iodide in heptane led to a very fast polymerization. The effect of butyl fluoride was found to be similar, but considerably weaker compared to tert-butyl fluoride and benzyl fluoride. Polymerizations with the catalyst system titanium(IV) chloride/benzyl fluoride were studied in greater detail. As it could be seen from the results, alkyl fluorides do not act as cocatalysts, but the polymerization of isobutene is due to catalytically active products arising from an exchange of halogen atoms between titanium halides and alkyl fluorides. The mechanism of initiation with the catalytic system titanium(IV) chloride/benzyl fluoride is discussed in connection with the results of the UV spectroscopic investigations of the polymers obtained. |
