Aqueous Phase Semihydrogenation of Alkynes over Ni-Fe Bimetallic Catalysts
Bimetallic Ni-Fe catalysts (Ni/Fe, 1:1, 1:3, and 3:1) are synthesized and explored for their catalytic activity in semihydrogenation of internal alkynes using H2 gas in water-ethanol solution. Our findings revealed that over Ni1Fe3 catalyst high diastereoselectivity for Z-alkenes with a high conversion for a wide range of internal alkynes can be achieved at moderate reaction temperature (40 ºC). Notably, the selectivity for the Z-alkenes is enhanced in the presence of n-butyl amine as an additive. Deuterium labeling experiments evidenced that H2 gas gets dissociated homolytically over the catalyst surface to hydrogenate alkynes to alkene. Synthesized catalysts were successfully characterized by the HR-TEM, SEM, XPS, EDS, P-XRD and H2-TPD.