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 H(2)gas in water-ethanol solution. Our findings revealed that over the Ni(1)Fe(3)catalyst a high diastereoselectivity forZ-alkenes with a high conversion for a wide range of internal alkynes can be achieved at moderate reaction temperature (40 degrees C). Notably, the selectivity for theZ-alkenes is enhanced in the presence ofn-butyl amine as an additive. Deuterium labeling experiments evidenced that H(2)gas becomes dissociated homolytically over the catalyst surface to hydrogenate alkynes to alkenes. Synthesized catalysts were successfully characterized by HR-TEM, SEM, XPS, EDS, P-XRD and H-2-TPD.