Grease And Fatty Acid Hydrogenation Active Catalyst

The hydrogenation of natural oils and fatty acids has been widely used in chemical and food industry, for example, the stearin obtained from coconut oil can substitute cocoa grease or is used as raw material of margarine. In addition, by the means of hydrogenation of Carbon-Carbon double bonds in oil, stearin, a kind of industrial raw material used in a large amount, can be prepared. All of these processes involve the catalysis hydrogenation. Therefore, the study of the preparation of high active catalysts for hydrogenation is of great significance. Many studies of catalysts for hydrogenation of oils and fatty acids have been made, in which Cu-Ni bibasic catalyst and Ni unitary catalyst are the two mainstreams. For the food industry, the Ni unitary catalyst is mainly adopted because of its high activity, and the hydrogenation products is of high anti-oxidation stability during their storage at room temperature. However, the Cu-Ni bibasic catalyst is also of such advantages as low cost and high activity. There are a lot of preparation methods of the catalysts which active component precursors also have many forms. For the supported catalyst, the crystal structure of supports, the surface area and pore distribution of the catalysts, have influences on hydrogenation activities and hydrogenation products. Thus, suitable preparation method and appropriate supports is the key to prepare industrial catalyst with high activity. In this paper, the catalysts have been prepared by using precipitation method and chemical mixing procedure. In these catalysts, the Ni unitary catalyst prepared by precipitation method exhibits very high activity. Characterization of the catalysts also has been made. Some main conclusions are as follows: 1. NiISiO2 catalyst prepared by chemical mixing procedure. Preparation conditions: Silica sol is obtained by ion exchange with sodium or water glass flowing through positive ion resin, controlled silica concentration 3.9%, pH 7 and formic nickel concentration 0.1 5mol.U? agitated for lh, made the sol gelatinized, washed by ethanol finally .The gel was dried quickly. NiISiO2 with high surface area is obtained. Operation conditions : 140-450 ; hydrogen pressure, 1.0 Mpa; reaction time, 90 mm. XRI), IR etc. show that Ni!Si02 is of high dispersity, high surface area. The interaction between active component and the support is observed. ? Hydrogenation products maintain oil's physical character except its melting ? point being enhanced. The catalyst is of high activity for hydrogenation of carbon -carbon double bonds. 2. Nildiatomite catalyst prepared by precipitation Preparation condition: A solution of N1SO4.6H20 and diatomite is agitated for I 0?0 mm, added Na2CO3 solution into the above solution until the pH value becomes 8---9, agitated for 1-3 h. The obtained solid which is basic carbonate nickel is filtered ,washed and dried at 110 . In order to transfer the basic carbonate nickel into formic nickel, superfluous formic acid is added to the solids, reacting for 3 h, then washed dried and sieved. Operation conditions: 140 502; hydrogen pressure, 1 .OMpa; reaction time, 90 mm. Physical and chemical characterization of the catalysts was carried out by means of atomic adsorption, activity and BET surface area measurement, X...