Effect of Catalyst Preparation on the Selective Hydrogenation of Vegetable Oil Over Low Percentage Pd/Diatomite Catalysts

Abstract

Hydrogenated vegetable oils contain high contents of <em>trans</em>-fatty acids. Because of the increased health concern about <em>trans</em>-fatty acids, new hydrogenations have been studied to seek ways for substantial reduction of the <em>trans</em>-fatty acids in the hydrogenated products. In this research, activated diatomite has distinctive properties as a support for hydrogenation catalysts. Investigation of textural properties of raw and purified diatomite samples reveals that during acid activation surface area increases significantly. Although, acid activation of diatomite is a commonly chemical modification to enhance its adsorption capacity. We are preparing adsorption method to synthesize low percentage 0.2% of Pd/Diatomite catalyst. The activated diatomite and the obtained catalyst was characterized by using thermogravimetric analysis (TGA), Brunauer-Emmett-Teller surface area analysis (BET), scanning electron microscopy (SEMEDAX), transmission electron microscopy (TEM). It was utilized for hydrogenation of sunflower oil using the Parr reactor in laboratory testing a variety of temperature (70, 90, 110 ºC) and canola oil in industrial testing, at temperature 90 ºC and 0.5 MPa pressure and compared to commercial nickel catalyst (Pricat-9910) at 150 ºC, 0.5 MPa pressure agitation of 800 rpm for 160 min. The changes in iodine value, fatty acid composition, <em>trans</em>-fatty acids, melting point and solid fat content were investigated on partial hydrogenated sunflower oil and canola oil. The experimentally obtained results show that the palladium catalyst is the most active compared to the commercial catalyst. Lower hydrogenation temperature used 0.2% Pd/Diatomite catalyst, significant reducing the formation of <em>trans</em>-content by 13% in fat.