Palladium-Catalyzed Methoxycarbonylation of 1‑Dodecene in a Two-Phase System: The Path toward a Continuous Process

The implementation of homogeneous catalysis in industry is still a challenging task due to the recycling of the mostly expensive catalyst complexes. The application of a liquid two-phase systems provides a viable approach to overcome this issue. Hereof, systematic lab investigations and the transfer to a continuously operated mini-plant for the palladium catalyzed methoxycarbonylation of 1-dodecene are presented (reaction volume scale up factor: 19). Under optimized reaction conditions, a yield of 92% to the corresponding ester was achieved after a reaction time of 20 h in lab-scale experiments. 97% of the product was located in the nonpolar phase and the catalyst was quantitatively immobilized in the polar phase. Subsequently, the proof of concept has been successfully carried out in a mini-plant, which was continuously operated over 100 h. The reaction performance in the mini-plant with a yield of esters of 83.5% and a chemo-selectivity of 91.2% was found to be comparable with the lab experiment. The catalyst leaching was permanently kept below 25 ppb, which validates the previous findings of the lab experiments. The catalyst remains stable and the formation of palladium black was prevented during the entire operation. By comparing lab and mini-plant results, a significant influence of the catalyst preformation process and the mini-plant operation mode on reaction rate and selectivity is identified.