Molecular Simulation of the Catalytic Regeneration of ⁿBuLi through a Hydrometalation Route

Efficient regeneration of organolithium compounds is a challenging aspect in the process of novel organometathetical catalytic cycles. One of these catalytic cycles is a newly suggested method for Mg production from seawater that capitalizes on the rich chemistry of Grignard reagents. The proposed three-step catalytic cycle with Cp₂ MCl L catalyst ( M = Ti, Zr; L = select organic ligands) requires the regeneration of ⁿBuLi from Li(s), butene, and H₂. The potential of this approach is evaluated with density functional theory-based molecular simulations. The results reveal that the high affinity of Li toward Cl and N results in the formation of alkanes, and the strong coupling between the catalyst and BuLi leads to catalyst deactivation. To improve its catalytic performance, we proposed the use of a diamine cocatalyst and a modified catalyst with a ligand that does not contain N, which would help release BuLi from the vicinity of the catalytic center. Ab initio molecular dynamics simulations at 298 K in explicit solvent (THF) were used to estimate the Gibbs free energetics and equilibrium constants obtained from the vibrational density of states using velocity autocorrelation functions. The results show a marked improvement in the free energetics with lower barriers toward the completion of the catalytic cycle and suppression of deactivation channels.