Zeolite-involved Selective Catalytic Oxidation Of Alcohols With Molecular Oxygen

The oxidation of alcohols to the corresponing aldehydes or ketones is of great importance in organic chemistry.2,2,6,6-Tetramethyl-piperidyl-1-oxyl (TEMPO), as an organocatalyst, has exhibited highly efficient performance in catalyzing the selective aerobic oxidation of alcohols. In this dissertation, a heterogeneous catalyst, copper-manganese oxide supported on NaX(13X) type zeolite is prepared, and in combination with TEMPO, allows the selective oxidation of various alcohols to the corresponding aldehydes or ketones with oxygen. The achievements are as follows:1. The Cu-Mn oxide/NaX zeolite catalyst is prepared with the impregnatation method, which operation is simple and safe.2. The molar ratio of Cu and Mn in Cu-Mn mixed oxide displays a significant effect on the catalytic activity. When the molar ratio of Cu and Mn is 3:1, the catalytic system gives the excellent results.3. The catalytic system consisting of the Cu-Mn oxide/NaX zeolite and TEMPO can catalyze efficiently the aerobic oxidation of benzyl alcohol. With 5 mol%TEMPO and 10 wt% Cu3MnOz/XZ, under 0.6 MPa O2 and 80℃,99.2% conversion of benzyl alcohol can be achived within 10 h in 100% selectivity of benzaldehyde.4. The catalytic system can realize the aerobic oxidation of other alcohols. Various substituted benzyl alcohols and cinnamyl alcohol give the nearly-quantiative conversion and selectivity.5. The catalytic system can work under neutral condition, and Cu3MnOz/XZ can be recovered and resued.6. Due to the regular aperture of zeolite, the system exhibits the shape-selectivity in catalyzing the aerobic oxidation of alcohols with different molecular radius. Only the alcohols with the smaller radius, which can enter the zeolite pore, are oxidized efficiently. In summary, the heterogeneous catalyst Cu3MnOz/XZ, in combination with TEMPO, can catalyze the aerobic oxidation of alcohols efficiently and selectivity with certain shape-selectivity.