Hydrogenation of sunflower oil over Pt–Ni bimetallic supported catalysts: Preparation, characterization and catalytic activity

Abstract

It had been reported that in order to improve oil hydrogenation catalysts the geometric or electronic effects of the catalysts must be manipulated in order to achieve the desired activity or selectivity. To achieve this, the development of an active and selective bimetallic catalyst was undertaken. An innovative approach was taken to synthesize Pt-Ni catalysts supported on mesoporous silica using the surface redox reaction (Srr) technique.It was determined that the Srr preparation method resulted in better activity and lower selectivity towards trans than the traditional successive and co-impregnation bimetallic impregnation techniques. The change in selectivity can be explained by a promoter electronic effect generated by the close proximity of a second metal on the catalysts surface and from a geometric effect due to the incorporation of the Ni on the surface. All the bimetallic catalysts showed a drop in the formation of trans compared to the monometallic catalyst.

Hydrogenation of soybean oil over various platinum catalysts: Effects of support materials on trans fatty acid levels

“…Therefore, the strength of double bonds is decreased with a decrease in the electronegativity of the metal ions in the support because the electron density of platinum particles is increased with a decrease in the electronegativity of the metal ions in support. McArdle et al proposed that the an increase in the electron donor characteristic by the addition of Ni to Pt would weaken the adsorption strength of double bonds, which result in the decrease in the TFA levels [11]. Thus, stronger hydrogen adsorption and weaker unsaturated fatty acid adsorption would result in the lower TFA levels because the half-hydrogenated intermediates are hydrogenated before the intermediates loose the hydrogen and form trans double bonds.…”

“…McArdle et al reported a platinum catalyst supported on mesoporous silica that had high catalytic activity and low TFA selectivity for the hydrogenation of sunflower oil [10]. In addition, they reported that the addition of nickel to Pt/SiO 2 catalyst improved the cis-isomer selectivity [11]. Hsu et al have reported a Pd/Al 2 O 3 catalyst with higher activity and lower TFA selectivity for the hydrogenation of canola oil than that for Pd/C and Pd/BaSO 4 catalysts [12].…”

“…Lower temperatures and higher pressures result in lower TFA levels [7]; however, it has not been possible to produce partially hydrogenated oils with low TFA levels. There have been numerous studies for hydrogenation of vegetable oils over supported metal catalysts, with many reports on the various modifications of nickel, palladium, and platinum catalysts to reduce TFA levels during hydrogenation [8][9][10][11][12][13][14][15][16][17][18]. For example, Li et al reported that a nickel-boron alloy catalyst has a lower TFA selectivity for the hydrogenation of soybean oil [8].…”

A theoretical view of 1,3-butadiene selective hydrogenation toward cis-2-butene on PdNi layered catalyst

“…In order to improve the sunflower oil hydrogenation, different bimetallic Pt/Ni catalysts supported on mesoporous silica were recently synthetized [19]. Experimental results show that the addition of Ni on Pt/SiO 2 catalyst produces a significant drop in the trans-formation, compared to the corresponding Pt monometallic catalyst.…”

Influence of Ni/SiO2 activity on the reaction pathway in sunflower oil hydrogenation

“…Although, amount of trans fatty acids produced during the process of oil hydrogenation, depends of the activity of used catalysts (McArdle et al, 2014) optimization parameter which increases activity also leads to the increased trans content (Kemache et al, 2009;Plourde et al, 2004;Rylander, 1970).…”