Phosphorus as a promoter of a nickel catalyst to obtain 1-phenylethanol from chemoselective hydrogenation of acetophenone

COSTA, DOLLY CAROLINA; MARCHETTI, SERGIO GUSTAVO; SOLDATI, ANALÍA LETICIA; VETERE, VIRGINIA; BENGOA, JOSÉ FERNANDO

Heliyon

Elsevier

Lugar: Amsterdam; Año: 2019 vol. 5 p. 1 - 9

2405-8440

Two catalysts were prepared using monodisperse pre-synthetized nanoparticles of metallic nickel and nickelphosphides with the same average diameter. Both nanoparticles species were deposited on the same support:mesoporous silica nano-spheres of MCM-41. This support is suitable to inhibit agglomeration and sinteringprocesses during preparation steps. Therefore, two supported and activated catalysts with the same averagenanoparticles diameter were obtained. They differ only in the nature of the active species: metallic nickel andnickel phosphides. The effect of the presence of a second element (phosphorus), more electronegative than nickel,on the activity and selectivity in the chemoselective hydrogenation of acetophenone was studied. The reactionconditions were: H2 pressure of 1 MPa, 80 C using n-heptane as solvent. With the aim to understand the catalyticresults, nanoparticles, support and catalysts were carefully characterized by X-ray diffraction, diffuse light scattering,transmission electron microcopy, high resolution transmission electron microcopy, selected area electrondiffraction, scanning electron microcopy, Fourier transformer infrared spectroscopy, N2 adsorption at -196 C,atomic absorption, H2 and CO chemisorption and volumetric oxidation. Considering these results and geometricand electronic characteristics of the surface of both active species, a change in the adsorption intermediate state ofacetophenone in presence of phosphorus is proposed to explain the hydrogenation chemoselectivity of nickelphospides.