Comment on "Mechanism and Kinetics of the Wacker Process : a quantum mechanical approach"

Abstract

Recently, a paper (“Mechanism and Kinetics of the Wacker Process: A Quantum Mechanical Approach” by S. Ali Beyramabadi, Hossein Eshtiagh-Hosseini, Mohammed R. Housaindokht, and Ali Morsali) appeared in Organometallics which concludes that anti-nucleophilic attack is the rate-determining step for the Wacker process (aerobic olefin oxidation via PdCl_2 and CuCl_2 in aqueous hydrochloric acid solution) under standard conditions.1 This paper also claims that these conclusions are consistent with experimental observations. In fact, as shown below, these conclusions dramatically contradict both experimental observations and other more complete calculations. Because of the importance of the Wacker process to the chemical industry and the many controversies and inconsistencies that confused the understanding of this system, we felt it important to bring to the attention of the Organometallics community that ethylene and olefin oxidation via PdCl_2 and CuCl_2 under standard conditions (low [Cl^-] and low [CuCl_2]) almost certainly proceeds via syn-nucleophilic attack.