Microkinetic Assessment of Ligand-Exchanging Catalytic Cycles

Abstract

Computational chemistry has become a fundamental part of the understanding and optimization of catalytic processes. Among these, the characterization of homogeneous organometallic catalysts, combining an active transition metal atom and set of ligands, is one of the main fields of application of these kinds of studies. More recently, microkinetic studies have been employed to bridge the gap between experimental measurements such as conversion or selectivity and the Gibbs free energies gathered by computations. In this work, we have developed an automated framework (MicroKatc) for microkinetic analysis, to tackle the yet understudied effect of ligand exchange processes that modify the nature of the catalytic scaffold in situ. We report the application of such a framework to the rhodium-catalyzed hydroformylation of ethylene, confirming the acceleration of the reaction as trimethylphosphine (PMe₃) displaces the carbonyl ligands in the catalyst by means of simulations at variable phosphine concentrations, as well as the determination of the degree of rate control (DRC) and apparent activation energies throughout the catalytic process.