Olefin oligomerization by zirconium boratabenzene catalysts

Abstract

In the present quantum chemical study, α-olefin dimerization and trimerization by zirconium boratabenzene catalysts has been studied as the single-site reactivity of group 4 metallocene catalysts has proven to be industrially important. The thermodynamics and kinetics of C=C insertion for ethylene, 1-butene, and 1-hexene as well as relevant ß-H elimination barriers have been quantified using density functional theory, using methodology previously calibrated in earlier research by the University of North Texas (UNT) and the ExxonMobil Chemical Company (EMCC) team for bis-indenyl zirconium catalysts. The insertions of the alkenes are relevant to chain growth processes, while the ß-H eliminations model chain termination. Various substituents on the boratabenzene rings were also compared to determine how these ligands change the thermodynamics and kinetics of the insertion and chain termination steps.