Sodium Acrylate Synthesis Through CO2 and Ethylene Coupling Catalyzed by Pd: Solvent Effects and PdBr2 as a Surprisingly Suitable Precursor

Abstract

AbstractPd‐catalyzed carboxylation of ethylene into sodium acrylate is an industrially relevant reaction that has gained increasing attention in the last years. By this process, CO2 can be transformed into a value‐added molecule in a single, high atom economy step. However, there is still some room for improvement since the productivity of the reference catalyst is rather low. A key aspect to achieve this goal concerns the good understanding of reaction mechanism. Herein, we combine experimental and DFT studies to gain some knowledge on the reactivity and catalytic performance of the Pd/dicyclohexylphosphinoethane (dcpe) system. First, we were able to understand the influence of the solvent on the reaction, and we demonstrated that DMF was the best candidate due to the more efficient formation of the Pd‐metallalactone. Moreover, we have demonstrated that highly available and less costly PdBr2 can be a suitable precursor, as PdII is reduced in situ in DMF in the presence of an excess of NaOtBu. Finally, the role of different monophosphine additives has been elucidated, which permitted us to rationally improve the catalytic performance.