Parts-Per-Million of Soluble Pd0 Catalyze the Semi-Hydrogenation Reaction of Alkynes to Alkenes

The synthesis of cis-alkenes is industrially carried out by selective semi-hydrogenation of alkynes with complex Pd catalysts, which include the Lindlar catalyst (PdPb on CaCO3) and c-Pd/TiS (colloidal ligand-protected Pd nanoparticles), among others. Here, we show that Pd-0 atoms are generated from primary Pd salts (PdCl2, PdSO4, Pd(OH)(2), PdO) with H-2 in alcohol solutions, independently of the alkyne, to catalyze the semihydrogenation reaction with extraordinarily high efficiency (up to 735 s(-1)), yield (up to 99%), and selectivity (up to 99%). The easy-to-prepare Pd-0 species hold other potential catalytic applications.

Automated summary

We have shown that Pd-0 atoms generated from primary Pd salts and H2 in alcohol solutions can catalyze highly efficient semi-hydrogenation reactions regardless of the type of alkyne. These easily prepared Pd-0 species also have other potential catalytic applications.