Homogeneous and heterogeneous catalysts for the synthesis of highly reactive polyisobutylene: discovery, development and perspectives
Irina V. Vasilenko, Sergei V. Kostjuk
Abstract
In this article, the current state and future perspectives in the application of complexes of Lewis acids with ethers in the synthesis of highly reactive polyisobutylene (HR PIB) were critically reviewed. The complexes of metal halides with ethers showed good activity and regioselectivity in the synthesis of HR PIB only in polar solvents due to their poor solubility in hydrocarbons. In strong contrast, HR PIB with high exo-olefin end group content was synthesized in non-polar n-hexane using fully soluble in hydrocarbons complexes of alkylaluminum dichlorides as catalysts. The further improvement in the synthesis of HR PIB was achieved using heterogeneous catalysts (acidic ionic liquids or liquid coordination complexes), which provides polyisobutylenes with high exo-olefin end group content in conjunction with low polydispersity.