We have established viability of cyclohexanone (C6ONE) production via coupled gas phase (1 atm, 423 K) continuous hydrodechlorination/hydrogenation of mono- and di-chlorophenols over bulk Pd and Pd/Al2O3. The catalysts have been characterised by temperature programmed reduction, H2 chemisorption, powder XRD and TEM analyses. Hydrodechlorination is not a thermodynamically limiting step where under catalytic control we achieve significantly greater C6ONE yields relative to those from standard phenol hydrogenation. We account for this response in terms of a direct chlorophenol C6ONE conversion facilitated by electron delocalisation in the intermediate generated via electrophilic hydrogen cleavage of C–Cl bond(s). The C6ONE selectivity/conversion profiles coincided for bulk and supported Pd and we demonstrate structure sensitivity for the production of C6ONE from 2,4-dichlorophenol with higher specific rates over larger Pd particles (2→250 nm).
Keane, M. A., Gomez Quero, S., & Cardenas-Lizana, F. (2016). Gas Phase Hydrotreatment of Chlorophenols over Pd Catalysts as an Alternative Route to Cyclohexanone. Reaction Kinetics, Mechanisms and Catalysis, 119(1), 35–48. https://doi.org/10.1007/s11144-016-1046-1