Olefin Purification and Selective Hydrogenation of Alkynes with Low Loaded Pd Nanoparticle Catalysts

The catalytic performance of Pd-nanoparticle catalysts for the selective hydrogenation of alkynes at mild conditions (150 kPa and 303 K) was evaluated. A Lindlar commercial catalyst was also tested for comparison. The effects of acidity, amount of active sites and dispersion on the catalytic activity and selectivity were studied. At mild conditions, Pd-nanoparticle catalysts were considerably more active and slightly more selective than the Lindlar catalyst. The best synthesized catalyst for the purification of 1-pentene was Pd/Al2O3-Mg (r0 = 41.1 mol gPd–1 min–1, 94% selectivity). The activity and selectivity of Pd/CaCO3 were similar to those of the Lindlar catalyst. The smallest particle sizes (3–4.5 nm) favored the dissociative adsorption of hydrogen over Pd° active sites and a good catalytic behavior. The weaker acid centers (Lewis) of Pd/Al2O3-Mg and Pd/CaCO3 favored higher selectivities to the desired alkene. Pd/Al2O3 was the most active catalyst but also the least selective. This was due to strong ...