HYDROGENATION OF POLY-α-OLEFINIC COMPOUNDS OVER PALLADIUM AND PALLADIUM-NICKEL CATALYSTS
Keywords:hydrogenation, palladium, nickel, diatomite, the catalyst, poly-α-olefin oils, activity, bimetallic catalyst, bromine number, kinematic viscosity, freezing point
Introduction. Poly-α-olefinic compounds are a component of base oils obtained by catalytic polymerization of linear alpha-olefins with subsequent hydrogenation, used for aviation and ground technology, and occupy an important place in the industry. Products of oligomerization contain one double bond; which needs to be hydrogenated to make it resistant to various chemical transformations during the production of lubricating oils. Methodology. Hydrogenation was carried out in an autoclave, which allows maintaining a constant temperature and pressure of hydrogen with measurement of the volume of absorbed hydrogen, excluding external diffusion inhibition. Catalysts were characterized by the following methods: specific surface area by BET, and particle size by transmission electron microscopy. The product of the reaction was characterized by the following methods: density, bromine number, IR, kinematic viscosity, and freezing point. Results and discussion. For the hydrogenation of poly-α-olefinic compounds, 0.5–1.0% Pd catalysts applied to modified natural diatomite clay are proposed. It is shown that modification with additional nickel leads to a decrease in activity. Conclusion. It has been found that palladium catalysts carry out the process under milder conditions, exhibit higher activity compared to nickel catalysts, significantly reduce the process time, and provide a higher degree of hydrogenation. The activity of bimetallic catalysts is lower than that of palladium catalysts. The physicochemical characteristics of polyalphaolefin oils have been determined.
It has been found that palladium catalysts carry out the process in milder conditions, show higher activity compared to nickel catalysts, significantly reduce the process time, and provide a higher degree of hydrogenation. The activity of bimetallic catalysts is lower than that of palladium catalysts.