Study On Ru/C Catalyst For Hydrogenation Of Butanone Prepared By Supercritical Fluid Deposition Process

The actived carbon supported ruthenium catalyst (Ru/C) is a kind of supportednoble metal catalyst. Its high specific surface area could finely disperse metals, and itssurface chemical properties can affect the catalytic activity of supported noble metalcatalyst. Ru/C catalyst is widely applied in hydrogenation, dehydrogenation andoxidation processes, in which the fine dispersion of Ru plays an important role. In thiswork, the supercritical fluid deposition is applied to prepare Ru/C catalyst. Theeffects of some preparation factors are studied systematically, in order to achieve thecontrollable synthesis. Meanwhile, the possible process mechanism is suggested.Under the optimized preparation conditions, the Ru/C catalyst is prepared and appliedto catalyze butanone hydrogenation. The orthogonal experimental design is used tooptimize the operation parameters of hydrogenation process, and the effect of theseparameters on butanone conversion are also analyzed.Through the comparison experiments, the advantage of SFD process in thepreparation of highly dispersed Ru/C catalysts is identified. The XRD and TEMcharacterizations show that the Ru particles in catalyst are of nano-size. When hydrateruthenium chloride and ruthenium acetylacetonate are used as soluble precursor saltsto prepare the Ru/C catalyst by SFD process, respectively, it is proved by TEMobservation and catalytic activity evaluation that the properties of catalyst preparedfrom latter salt are superior to those from former. The effects of Ru loading on theproperties of Ru/C catalyst are investigated. It is found that the Ru/C catalyst with2wt%loading shows higher Ru dispersion degree and catalytic hydrogenation activity.The effects of temperature and pressure in preparation process are also investigated.Under the optimized conditions of45℃and13MPa, the Ru dispersion in Ru/Ccatalyst is most homogeneous.Ethanol is used as co-solvent of supercritical fluid to improve solubility ofruthenium salt. The usage amount of ethanol could influence the dispersion ofruthenium and hydrogenation activity. Owing to the solubility of ethanol in SC-CO2,it is suggested that the supercritical fluid anti-solvent phenomena might carry out inthe system. It is also discovered experimentally that ruthenium acetylacetonate couldbe separated out from the solution of ruthenium acetylacetonate in ethanol and supercritical carbon dioxide. The TG-MS, TPR, and FTIR tests for the catalystprecursors and ruthenium acetylacetonate show that there would exist the interactionbetween ruthenium acetylacetonate and activated carbon.The Ru/C catalyst prepared under the optimized conditions is applied to thecatalytic hydrogenation of butanone. The orthogonal experimental design is adoptedto optimize the operation parameters. Among the investigated parameters oftemperature, initial hydrogen pressure, mass ratio of catalyst to raw feed and reactiontime, the temperature and initial hydrogen pressure have showed the more significantinfluences on the butanone conversion. The butanone conversion increases with theincrease of temperature and pressure.