Cobalt-based Catalyst Cyclohexene Hydroformylation

After reading some relevant literature, we decided to use cobalt chloride metal powder and sodium thiosulfate as precursor of the catalyst. At the beginning of our research, we studied the influence of Mn, Fe, Zn , Mn Fe alloy powder and raney nickel on the reaction. The results showed that the best metal powder is Mn Fe alloy. Then we studied the influence of sodium thiosulfate on the reaction. We find out that adding to the suitable amount of sodium thiosulfate play an import role in the reaction. At the same time sodium thiosulfate can raise the selectivity of reaction. After these researches we got the best reaction condition. Then we studied cobalt-based catalyst for hydroformylation of cyclohexene. The effects of solvent, temperature and pressure in the system on the reaction were investigated. The THF (tetrahydrofuran) is a good solvent for the reaction. The results reveal that the optimal reaction condition is Ptotal = 8.0 MPa, nCo / nalkenes = 0.01, and T = 145℃. The conversion of cyclohexene is 89% and selectivity of Cyclohexanecarboxaldehyde is 96% under the optimal reaction condition. Then we we studied influence of carbonyl manganese on the reaction, and find out that carbonyl manganese can raise the activity of the cobalt carbonyl catalyst, but the mechanism is still not very clear. According to our researches ruthenium trichloride can raise the activity of catalyst, but selectivity is not good enough. The phosphine ligand also have obvious influence on the reaction. After we added the phosphine ligand, the activity of the catalyst is not as good as before. In order to research the influence of lewis acid on the reaction, we used corrosion resistance autoclave which is made by Zirconium steel. The result shows that anhydrous aluminum chloride can raise the activity of catalyst obviously, and the selectivy is also not bad. In order to study the mechanism of the reaction, we used the in situ FTIR to detect the reaction of synthesis of cobalt carbonyl under the normal pressure. The results are match to our speculation.