Green Catalytic Synthesis Of Several Important Pharmaceutical Intermediates

The classical synthesis methods such as the use of high oxidation state transition metals for syntheses of important intermediates for drugs and pharmaceuticals need critical conditions, especially, they are polluting and risky. Therefore, more and more attention has been transferred to develop a more efficient, easily separable, reusable, and environment-friendly catalyst.The well-ordered mesoporous materials, particularly, incorporated with metal ions, have a good use in catalysis for their unusual properties:monodispersed, single-pore distributed, huge pore volume and highly ordered mesoporous structures. Therefore, it was suggested a good possibility to apply transition metal doped mesoporous materials for the first time as a catalyst for the syntheses of some important intermediates.In this thesis, the results obtained are described as follows:1. Transition metals doped MCM-41, SBA-15, and mesoporous titania with anatase crystalline structural wall were prepared. They were characterized by nitrogen adsorption, XRD, TEM, SEM, FT-IR and UV-Vis spectroscopy. Transition metals were well dispersed.2. Cu/MCM-41 and Cu/Al2O3 presented high catalytic activity to catalyze p-methoxyltoluene. The main products of this reaction included 2-methoxy-5-methyl-p-benzoquinone, When Cu/SBA-15 was used as a catalyst, the major product of oxidation reaction was p-methoxy-benzaldehyde. MCM-41, Al2O3, SBA-15 without doping metal ions can not catalyze p-methoxyltoluene. The catalytic activity of Cu/MCM-41 was the highest. The conversion of p-methoxyltoluene was 81%, and the selectivity of 2-methoxy-5-methyl-p-benzoquinone was 78%. When Cu/MCM-41 was used as a catalyst to catalyze the oxidation of phenol, p-benzoquinone was the major oxidative product.3. Co/MCM-41 was used as a catalyst to catalyze the oxidation of diphenylmethane to benzophenone. It exhbited a selectivity of benzophenone 95.8%, and conversion of diphenylmethane 21%. While, Cu/MCM-41 and Co/TiO2 exhibited much lower activity. 4. Co/MCM-41 showed the high level of the catalytic activity in the oxidation of 4-tert-butylbenzaldehyde.4-tert-butylbenzaldehyde was obtained as the major product, 4-tert-butylphenol and 4-tert-butyl benzyl alcohol are also detected. The change of the reaction temperature resulted in the increase of 4-methyl-acetophenone. The difference between Co/MCM-41 and Co/TiO2 implies that mesoporous silica was more suitable than mesoporous titania although both of them were doped the same cobalt ions. Compared with different Si/Co ratio, Co/MCM-41 with Si/Co ratio of 20 exhibited much lower conversion rate and selectivity than that with Si/Co ratio of 40. Co/MCM-41 as a catalyst can be used once without losing the activity.5. Co/TiO2 was utilized as a new catalyst to catalyze the oxidation of bromotoluenes to bromobenzaldehyde. The catalytic activity of Co/TiO2 was the highest, the conversion of p-bromotoluenes was 34.5%, and the selectivity of bromobenzaldehyde was 90.6%. The main oxidative product was bromobenzaldehyde, and a small amount of bromobenzoic acid was detected in the reaction. The results suggested that the oxidation of p-bromotoluene was easier than the oxidations of o-bromotoluene and m-bromotoluene.6. Co/TiO2,Co/SBA-15,Co/MCM-41,SeO32-/MCM-41 were used as catalysts to catalyze the oxidation of cyclohexene. The major product of oxidative reaction was 2-acetoxycyclohexanol, and a small amount of 1,2-cyclohexediol (CHDL) and 2-cyclohexen-l-one was detected in the reaction. Co/MCM-41 as a catalyst, the main reaction was the oxidation of the allyl in cyclohexene. SeO32-/MCM-41 presented the highest catalytic activity, and the main reaction was the cyclohexene epoxidation. The conversions of cychohexene reached 100% while the selectivity of 2-acetoxycyclohexanol was 81%.