**2.1. Materials used**

The support materials used for the synthesis of nickel-based catalysts were diatomite, silica gel and perlite. Diatomite support (D) was prepared from local crude diatomite (Baroševac- ″Kolubara″ coal basin, Lazarevac, Serbia) in our laboratories (IChTM-DCCE, see [67]). The crude material was mechanically, chemically and thermally treated to obtain the desired support characteristics. Three types of commercial silica gel with different textural characteristics (silica gel-A, silica gel-B, silica gel-C, silica gel = SiG hereinafter expressed as SiG-A, SiG-B and SiG-C, see [68]), produced in Bulgaria, were used for the preparation of the nickel-based catalyst supported on silica gel. Expanded perlite (PF, commercial product Perfit PF-295) supplied with the courtesy of Termika Zrenjanin, Serbia, was used for synthesis of nickel-based catalysts on perlite. Some of their characteristics are summarized in **Table 1**.

Refined, bleached and deodorized commercial sunflower oil (Dijamant AD Company, Zrenjanin, Serbia) along with refined and bleached soybean oil provided by Factory of Oils and Vegetable Fats Vital-Vrbas, Serbia, were used in the hydrogenation experiments. The initial iodine value (IV) and the fatty acid composition of sunflower and soybean oil are listed in **Table 2**.


\*SiO2 content (wt%): Diatomite (D)—93.07; Silica gel (SiG-A, SiG-B, Sig-C)—100; Perlite (PF)—74.10.

a Determining surface area, adsorbed volume and pore size distribution in the micro- and mesopore ranges: *S*BET—BET specific surface area; *V*micro—specific pore volume (micropore range: D < 2nm); *V*meso: specific pore volume (mesopore range: 2 nm < D < 50 nm).

ᵇDetermining total pore volume and pore size distribution in the meso- and macropore ranges: VP—specific pore volume at 200 MPa; pore diameter: Dmean—mean pore diameter; P—total porosity; constant surface tension for Hg was assumed: γ = 480 dyn cm-¹ .

c Helium picnometry—determining apparent density: *ρ*app—includes closed pore (IUPAC).

**Table 1.** Typical catalyst support characteristics.

of the catalyst could be changed by the nature of the supported Ni2+ phase, thus acquiring different characteristics and exhibiting different performances toward activity and selectivity, which are known to vary considerably with changes in the preparation conditions [41]. To control the fatty acid composition through temperature, pressure, catalyst and reaction time it is necessary to have a kinetic equation. The kinetic equations based on complex mechanisms as Horiuti-Polanyi [58] obtained from an extensive experimental work, give good results for predicting the reaction products, but in practice, simple mechanisms are employed with approximate results. An alternative is to use empirical modeling approach, which includes

The present work contains a part of our comprehensive research that we conducted on different nickel-based supported hydrogenation catalysts for their use in partial hydrogenation of edible oils. In this work, the characteristics and the structure of high loading nickel-based catalysts supported on diatomite, silica gel and perlite of different properties are related to their activity and selectivity in the hydrogenation of sunflower and soybean oils. Nitrogen physisorption and mercury porosimetry measurements, infrared and X-ray diffraction spectroscopy analyses, temperature programmed reduction studies, quantitative hydrogen chemisorption measurements and X-ray photoelectron spectroscopy were used. The kinetic models for hydrogenation of soybean and sunflower oils were developed to obtain the related kinetic parameters. The partial results derived of each one, treated together, have allowed us to present an overall picture of the nickel-based supported catalysts and some conclusions concerning the relationship in the triad—synthesis, structure

The support materials used for the synthesis of nickel-based catalysts were diatomite, silica gel and perlite. Diatomite support (D) was prepared from local crude diatomite (Baroševac- ″Kolubara″ coal basin, Lazarevac, Serbia) in our laboratories (IChTM-DCCE, see [67]). The crude material was mechanically, chemically and thermally treated to obtain the desired support characteristics. Three types of commercial silica gel with different textural characteristics (silica gel-A, silica gel-B, silica gel-C, silica gel = SiG hereinafter expressed as SiG-A, SiG-B and SiG-C, see [68]), produced in Bulgaria, were used for the preparation of the nickel-based catalyst supported on silica gel. Expanded perlite (PF, commercial product Perfit PF-295) supplied with the courtesy of Termika Zrenjanin, Serbia, was used for synthesis of nickel-based

Refined, bleached and deodorized commercial sunflower oil (Dijamant AD Company, Zrenjanin, Serbia) along with refined and bleached soybean oil provided by Factory of Oils and Vegetable Fats Vital-Vrbas, Serbia, were used in the hydrogenation experiments. The initial iodine value

catalysts on perlite. Some of their characteristics are summarized in **Table 1**.

(IV) and the fatty acid composition of sunflower and soybean oil are listed in **Table 2**.

mathematical and statistical techniques for chosen empirical model [59–66].

134 New Advances in Hydrogenation Processes - Fundamentals and Applications

and properties.

**2. Experimental**

**2.1. Materials used**


a Initial unsaturation of soybean and sunflower oil was measured in terms of IV.

b First number represents the total carbon number of the acyl groups and the second number represents the total number of double bounds.

c Sum: C18:2*c,t* + C18:2*t,c* + C18:2*t,t*.

**Table 2.** Iodine value (IV) and fatty acid composition of soybean and sunflower oils.

Analytical grade chemicals and pure hydrogen (99.999%) and nitrogen (99.999%) were employed in the experiments and none of these gases contained catalyst-poisoning substances such as oxygen or sulfur.
