Liquid-phase hydrodechlorination of chlorobenzene by molecular hydrogen: The influence of reaction medium on process efficiency

Catalytic hydrodechlorination (HDCl) of chlorobenzene was carried out in a two-phase aqueous-organic solvent system and a single-phase solvent composed of saturated KOH solution in a secondary alcohol over Pd-based catalysts at 50 degrees C and atmospheric pressure of H(2) It was shown that an aqueous-organic solvent system containing propan-2-ol and aqueous KOH increases catalyst activity by promoting mass transfer of the formed chloride ions to water phase that prevents catalyst deactivation. It is inferred that propan-2-ol favors hydrogen activation during the HDCl process. Use of the Pd catalysts based on hydrophobic carbon support enables chlorobenzene HDCl to proceed in a two-phase solvent at a satisfactory rate, even in the absence of phase-transfer catalysts.