Selective hydrogenation of diphenylacetylene using NiCo nanoparticles supported on mesoporous carbon as catalyst

Abstract

Hydrogenation of alkynes to alkenes is an important procedure in the synthesis of organic compounds. In this study, selective hydrogenation was carried out on diphenylacetylene as a model of alkyne compounds using NaBH₄ as a hydrogen source and NiCo bimetallic nanoparticles supported on mesoporous carbon (NiCo/MC) as a catalyst. The mesoporous carbon was prepared using the soft-templated method from phloroglucinol and formaldehyde as precursors while the NiCo/MC catalyst was synthesized using a wet impregnation method. Based on surface area analysis, it was found that the pore diameters of MC, Ni/MC, and NiCo/MC were 12.8 nm, 13.4 nm, and 12.7 nm respectively, which indicated the mesoporous size of the materials. TEM analysis also confirmed the formation of nanoparticles on mesoporous carbon with the average size similar to the pore structure of the support, thus indicating the incorporation of the metals on the support. The hydrogenation reaction of diphenylacetylene was carried out with variations in reaction time and temperature. GCMS analysis of the products showed that the optimum conditions were obtained over NiCo/MC catalyst at 50 °C for 4 h with a diphenylacetylene conversion of 71.5% and a selectivity of 87.1% for the formation of cis-stilbene.