Solvent effects in the catalytic hydrotreament of haloaromatics over Pd/Al2O3 in water+organic mixtures

Solvent effects have been studied for the liquid phase (atmospheric pressure, T=303 K) hydrodehalogenation (HDH) of a range of haloarenes in methanol, THF, water+methanol and water+THF promoted by Pd/Al2O3. The catalyst has been characterized in terms of temperature programmed reduction, XRD, TEM, BET and pore volume measurements: the active Pd phase is present as nano-scale particles (<1–6 nm, surface area weighted mean diameter=2.4 nm). In the absence of transport limitations, catalyst deactivation and secondary reactions, the following sequence of increasing dehalogenation rate has been established: dichlorophenol(s)