Aerobic dehydrogenation of cyclic ketones into corresponding phenols catalyzed by heterogeneous Pd nanocatalysts

The Pd, Ni, Ni-Sn, Cu and Ag@Pd nanocatalyst having different shape and size were used for direct dehydrogenation of cyclic ketones to the corresponding phenols in the presence of O2 as the oxidant. Among all catalyst tested, metallic Pd-1 nanoparticles exhibited excellent catalytic performance both in presence and absence of p-toluenesulfonic acid. The dehydrogenation of cyclohexanone catalyzed by Pd-1 nanocatalyst led to a 93% yield of the desired cyclohexenone and phenol. X-ray diffraction (XRD) and transmission electron microscopy (TEM) confirmed that there was no change in morphology, crystal phases and particles size of Pd-1 nanocatalyst after the reaction.