| Bromination of butyl rubber introduces an allylic bromide functionality, which enhances the cure reactivity of sulphur-based formulations.; On being subjected to high temperatures, the allylic bromide undergoes elimination reactions to generate conjugated dienes, which can be used to generate new derivatives of butyl rubber. The objective of the project was to study the elimination reactions of brominated butyl rubber and its cycloaddition reactions with maleic anhydride to generate maleated products, as well as the degradation side-reactions that may affect product quality. Brominated 2,2,4,8,8-pentamethyl-4-nonene (BPMN), which accurately represents the reactive functionality of brominated butyl rubber, was used as a model compound to characterize the elimination, fragmentation and maleation products.; Dehydrobromination of the allylic bromide at high temperatures, in presence of an effective acid scavenger, generates the exo-conjugated diene as the kinetically favoured product.; Reaction between the conjugated dienes and maleic anhydride via a Diels-Alder mechanism generates the cycloaddition product at room temperature. (Abstract shortened by UMI.)... |
