Preparation and characterization of Ni‐Agx/SBA‐15 and its catalytic properties on the hydrogenation of soybean oil

Abstract

Ni‐Agx/SBA‐15 catalysts with different contents of the silver (Ag) promoter were prepared by the co‐impregnation method using the support of the mesoporous material SBA‐15. The Ni‐Agx/SBA‐15 catalysts were characterized by ICP‐OES, X‐ray diffraction (XRD), transmission electron microscope (TEM), and N2 adsorption–desorption isotherms. The activity of the catalysts on hydrogenation of soybean oil was evaluated. The results indicated that all the catalysts retained the hexagonally ordered structure of SBA‐15, the binding force between SBA‐15 and Ni was enhanced by the addition of the Ag promoter, and Ni was well loaded on the surface and the interior of the support that was beneficial to the improvement of catalyst activity. TEM images of the catalysts show that the addition of the silver can promote the dispersion of nickel particles over and inside the mesoporous channels of the SBA‐15 support, and the aggregation of metal nickel particles was decreased. The catalysts of Ra‐Ni (Raney Nickel), Ni/SBA‐15 and Ni‐Agx/SBA‐15 were used in the hydrogenation of soybean oil. The results show that Ni‐Ag0.15/SBA‐15 in hydrogenation processing has higher catalytic activity, and the obtained hydrogenated soybean oil has low trans fatty acids (TFAs) content. The use efficiency of the catalyst decreased to 60% after 8 cycles. Practical applications The main objective of this work was to hydrogenate soybean oil. Very encouraging results were obtained with Ni‐Ag0.15/SBA15. This preparation had a higher catalyst activity to obtain low trans fatty acid content. This finding is very valuable for fat and oil processing at the industry level.

Catalytic Transfer Hydrogenation of Low-erucic-acid Rapeseed Oil over a Ni-Ag_0.15/SBA15 Catalyst

“…It was necessary to control the formation of trans fatty acids and stearic acid as much as possible to increase the oleic acid content. Although the fatty acid composition of soybean oil and low-erucic rapeseed oil are different, the decrease in the reaction temperature led to a decrease in the trans fatty acid content 16 .…”

“…In the application of silver-nickel catalysts, because the active metal nickel tends to cluster on the support during the preparation of the supported catalyst, silver is beneficial for the prevention of the metallic nickel cluster 15 . It was pointed out that in nickel-silver/SBA15 catalysts, an appropriate amount of silver increase the dispersion of metallic nickel 16 .The addition of an appropriate amount of silver in the nickel catalyst can also effectively inhibit the formation of trans fatty acids 17 . Ni-Ag catalyst was shown to exhibit a better selectivity for linoleic acid and lower isomer formation 18 .…”

“…acid: 52 , erucic acid: ≤ 5 ; ammonium formate solution prepared in the laboratory .2.2 Experimental methods2.2.1 Catalyst preparationNi-Ag 0.15 /SBA15 was prepared by the coimpregnation method with the mass fraction of 12 Ni metal and silver nitrate as the main catalyst16 . 2.2.2 Method for the preparation of CTH low-erucic-acid rapeseed oil The overall mechanism of catalytic transfer hydrogenation CTH using ammonium formate as the hydrogen donor can be expressed as22 :…”