Stereospecific polymerization of 1,3-butadiene catalyzed by iron (III) Salen complexes combined with exogenous electron donor

Iron Salen complexes varied with steric effect were designed and examined in polymerization of butadiene coupled with triphenylphosphate as electron donor. The results demonstrate they are able to serve as unique catalysts, yielding a family of crystalline 1,2 syndiotactic polybutadienes as thermoplastic resin materials. The incorporation of sterically hindered group into the iron catalyst provides a high degree of control over the stereospecificity with certain adverse effect on activity. The necessity of donor during the stereopolymerization of butadiene is also highlighted by concomitant increase in activity and selectivity at higher temperature. The formed stereo active sites are very uniform in nature irrelative to the alkylaluminum and monomer feeding, resulting in polymers having constant microstructures and stable properties. The highly stable catalytic performances by the catalyst formed by accessible catalyst component could be industrially favored for production of syndiotactic 1,2 polybutadiene.