Liquid phase hydrogenation of crotanaldehyde over nickel supported on titania

The catalytic hydrogenation of crotanaldehyde to produce crotyl alcohol employing Ni impregnated on rutile, anatase and high surface area titania supports has been investigated. The Ni is present in elemental state as fcc phase on the catalyst as evidenced by XRD results. The TPR results suggest a greater metal–support interaction in case of Ni/rutile. SEM images show a rectangular morphology for Ni/rutile and spherical morphology for Ni/TiO2 and Ni/anatase. The observed order of catalytic activity for the hydrogenation of crotanaldehyde is Ni/rutile > Ni/anatase > Ni/TiO2. The activity trend suggests that a higher dispersion of Ni has detrimental effect while surface concentration of Ni atoms determines the conversion of crotonaldehyde. The conversion (60%) and selectivity (86.4%) are found to be optimum at 70 °C and hydrogen pressure of 10 kg/cm2. Both Ni/rutile and Ni/anatase exhibited a better stability than Ni/TiO2. An increase in conversion with hydrogen pressure suggests preferential adsorption of hydrogen on Ni present on the catalyst surface. A higher selectivity for crotyl alcohol suggests a more favorable adsorption of CO group which is influenced by TiOx species present in the support.

Graphical abstractThe hydrogenation of crotanaldehyde on Ni/titania proceeds with the preferential adsorption of hydrogen on the Ni present in the catalyst surface. The selectivity to crotyl alcohol is influenced by the TiOx species present in the catalyst.Figure optionsDownload full-size imageDownload high-quality image (109 K)Download as PowerPoint slideHighlights► Hydrogenation of crotonaldehyde studied using Ni/titania catalysts. ► Selective carbonyl group hydrogenation is influenced by TiOx interfaces. ► The order of catalytic activity is: Ni/rutile > Ni/anatase > Ni/TiO2. ► The activity trend suggests that a higher dispersion of Ni has detrimental effect.