The Hydrogenation And Selective Hydrogenation Of Phytosterols

Due to its unique biological characteristics and physicochemical properties, phytosterol and its deep processing products are widely used in food, medicine, cosmetics and other industries, and many products have been commercialized. Internationally, more than70percent of the commodity phytosterols, at present, derived from soybean oil deodorizer distillate.Phytostanols alkanol, the hydrogenated phytosterols, has a more hydrophobic and lipid-lowering effect than the phytosterols. Because phytostanols alkanol is more hydrophobic (or fat-soluble) than phytosterols after the hydrogenation, it can make cholesterol secretion and excretion more effective. And phytostanols alkanol has low solubility, and can hardly be absorbed, so it will not cause an increase in blood cholesterol, and its mechanism of action is to reduce serum cholesterol concentrations by inhibiting the absorption of cholesterol in the small intestine.The topic of this paper is chosed on-demand, the main purpose of this paper is the study of hydrogenation and selective hydrogenatio processes of phytosterols, and make optimization.Through the establishment and optimization of the phytosterols detection methods, changes in the composition of phytosterols in the hydrogenation process will be detected, so the desired products will be obtained, and make determination and optimization of the conditions of selective of phytosterols.There are many ways to analysis the phytosterols and phytostanols alkyl, but considering cost and monitoring efficiency for products in the large number of tests, the chemical reagents color or method of hydroxyl value has been established, combined with the iodometric method to determine the rate of hydrogenation of phytosterols.According to single factor and orthogonal experiments, the conditions of the method of hydroxyl value are:sampling weight,1.70g, Pyridine-Acetic anhydride (3:1),5ml/g, recation time,50min, temperature,80℃, n-Butanol,5ml, and the hydroxyl value of phytosterols maintains between125～130mgKOH/g. Hydrogenation products of phytosterols were detected with the method of hydroxyl value consistent with the results measured by HPLC method.On the basis of previous work,this paper used phytosterols as raw materials, isopropyl alcohol as solvent, and Raney Nickel and Palladium Carbon as catalyst to study hydrogenated affecting factors on the hydrogenation of phytosterols and selective hydrogenation, and to optimize the process parameters of selective hydrogenation. Using Raney Nickel as the catalyst, and through the single factor experiments, the mainly factors affecting the selective hydrogenation reaction of phytosterols are reaction temperature and pressure, and Raney Nickel is selective under low temperature and medium pressure, the basis of single factor experiments,the optimum reaction conditions found by orthogo design method were:70℃,2.5Mpa. Using Palladium Carbon as the catalyst,through single factor experiments, the mainly factors affecting the selective hydrogenation reaction of phytosterols are also reaction temperature and pressure, Palladium Carbon was selective at ambient temperature and pressure. On the basis of single factor experiments, the optimum reaction conditions found by orthogonal design method were:20℃,0.1Mpa.