Ruthenium-based Amorphous Alloy Catalyst Benzene Selective Hydrogenation To Cyclohexene

The main contents of this dissertation are:1. Preparation of Ru catalysts prepared by chemical reduction method: Ru- M- B/ZrC>2(MisoneofFe^ Zn> Cu and Co) amorphous catalysts were prepared by chemical reduction method. The suitable ratios of M/Ru is 2%, and the proper Ru/ZrOa isWhen Fe/Ru is 2% and Cu/Ru is 1.5%, over the Ru- Fe- Cu- B/ZrO2 catalyst, benzene conversion and cyclohexene selectivity are better than that over the Ru- Fe- Cu- B/ZrOa with other Fe/Ru and Cu/Ru ratios.Ru - Fe - B/BaSO4 catalyst was made, in which BaSC>4 is dispersant. The selective benzene hydrogenation consequence with Ru- Fe- B/BaSO4 is far lower than the consequence with Ru- Fe- B/ZrOa. ZrC>2 can not only disperse the active component but also improve the reaction activity and cyclohexene selectivity.Benzene conversion and cyclohexene selectivity are very good over Ru- Co/ZrO2 catalyst reduced by HCHO.2. Hydrogenation reaction conditions with Ru catalysts:The effect of reaction pressure and temperature on selective benzene hydrogenation was studied. The optimum hydrogen pressure is 4MPa~5MPa, and the proper reaction temperature is 403K-423K.Benzene conversion is lowed and cyclohexene selectivity is increased when pretreatment time was prolonged and maximum pretreatment temperature was raised.3. Lifetime of Ru catalysts:The lifetime of Ru catalysts were investigated by two kinds of methods of the continuous lifetime test and before- after lifetime test. Compared with Ru- B/ZrO2 catalyst, reaction activity descent over Ru- Zn- B/ZrO2 catalyst has the different trend. The lifetime of Ru- Zn - B/ZrC>2 catalyst is longer.The promoter Zn in Ru- Zn- B/ZrC>2 catalyst can repress the aggrandizement of catalyst particle size, prevent catalyst from sintering, and prolong the lifetime of catalyst. After treated deeply at long time under high temperature, the particles grow up. Therefore the reactionactivity and cyclohexene selectivity descend. After reproduction the catalysts can be utilized repeatedly.4. Characterization of Ru catalysts:XRD patters and SEM pictures show that Ru catalysts prepared by chemical reduction method are amorphous. The test of Ru catalyst particle expresses that reaction activity and cyclohexene selectivity depend on the size of catalyst particle. Therefore the particle size should be around 5nm.According to BET surface area measurements, the dispersant ZrC>2 can increase the surface areas of catalysts, enlarge the degree of Ru catalysts dispersion, and repress the aggrandizement of catalysts particle.TG-DTA curve of Ru-Co/ZrO2 catalyst reduced by HCHO shows the mass of catalyst do not change when the catalyst is heated below 673K. The catalyst is oxidized slowly when it is heated above 673K. It shows that Ru-Co/ZrO2 has very good thermostability. In addition, the only apparent thermopositive peak in the DTA curve expresses that amorphous Ru-Co/ZrC>2 can change into crystal directly when it is heated under 473 K.The main conclusions are as follows:1. Ru-Co-B/ZrO2 catalysts was prepared by chemical reduction method. CoCl2 was adopted as new promoter during catalyst preparation course. In comparison to the catalyst which used promoter Fe or Zn, high reaction activity and cyclohexene selectivity are obtained with Ru -Co-B/ZrO2.2. The lifetime of Ru catalysts was discussed with two kinds of test methods. It was researched that the promoter has the function of prolonging catalyst lifetime. These studies can provide experimental basis for the future industry application of Ru catalysts.