Catalytic Oxidation Of Limonene To Carvone Over ZIF-67(Co) And Co/MIL-53(Al)

Carvone, one of the most valuable compounds derived from the allylic oxidation of limonene, has widely applications in food additives, fragrance and pharmaceutical industries. Therefore, its synthesis is an important organic chemical reaction. However, the industry syntheses of carvone from limonene are often performed in environmentally unfriendly conditions, producing toxic end-products and difficult to separate products. In the context of this, it is definitely critical to develop new and high efficient heterogeneous catalysts for the increase in yield of carvone.Metal-organic frameworks (MOFs) are new members of porous nanomaterials with hybrid organic-inorganic supramolecular structures. They are much more attractive in catalysis and adsorption process in comparison with traditional porous materials becuse of their advantages such as high surface areas, well-defined structures, special metal centers, the ease of processability and structural diversity. Herein, several MOFs have been used in catalytic oxidation of limonene. The main contents of the research are as following:(1) ZIF-67(Co) and Co loaded MIL-53(A1) and were synthesized by using different organic ligands through solvothermal method. The obtained samples were characterized by Powder X-ray diffraction (PXRD), N2adsorption/desorption measurement, Scanning electron microscopy (SEM), Transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR) and Thermogravimetric differential thermal analysis (TG-DTA).(2) The obtained materials were used as catalysts for oxidation of limonene. The effects of amount and kind of catalyst used, the doped amounts of the transition metal, solvent, oxidant, reaction temperature and reaction time on the productivity, as well as the reaction mechanism were investigated. When using ZIF-67(Co)(85mg) as catalyst, benzene as solvent (12mL), the tertiary butyl peroxide hydrogen as oxidant (3mL), reaction temperature75℃and reaction time8h, the conversion of limonene was29.8%with the selectivity of55.4%toward carvone; When using Co/MIL-53(Al) (100mg) as catalyst, cobalt loads10wt.%, acetic anhydride as solvent (14mL), the air as oxidant, reaction temperature85℃and reaction time14h, the68.5%limonene conversion and39.7%selectivity for carvone were chieved.