Continuous Photo‐Electro‐Catalytic Synthesis of Bio‐Based Adipic Acid with Reaction Kinetics Modeling

Photo‐electro‐catalytic oxidation reactions of 1,6‐hexanediol were carried out in a coil‐type continuous‐flow microreactor with an immobilized TiO2 catalyst material. Bio‐based adipic acid was formed as the only intermediate product before the total mineralization process. The production was stable, enabling green, selective and continuous resource conversion, but with low, non‐optimized yields. In addition, the catalyzed chemical kinetics was modeled, based on mechanisms as well as approximated rate‐determining steps. The Butler‐Volmer relation was used for activation. The electro‐catalytic oxidative pathway was demonstrated to dominate over photo‐catalysis, also on account of the band gap characteristics of the titania nanotube electrode. Bio‐based adipic acid was synthesized photo‐electro‐catalytically from 1,6‐hexanediol in a continuous‐flow microreactor with an immobilized TiO2 catalyst. The electro‐catalytic oxidative pathway is shown to dominate over photo‐catalysis, due to the band gap characteristics of the titania nanotube electrode.