Study On Expoxidation Of Styrene To Styrene Oxide Catalyzed By Prussian Blue Analogues

With the continuous enhancement of the awareness of environmental protection, the environmental pollution problems caused by styrene oxide production got more attentions. Now, the demands for development of green and environmental-friendly chemical process are increasing. The key of meeting the demands is to find high-efficient, selectivity and stable catalysts. Styrene oxide is an important chemical product, and the studies on expoxidation of styrene catalysed to styrene oxide not only has important theoretical significance, but also has broad application.Herein, the CuCo, FeCo, CuFe, NiFe of Prussian Blue Analogues (PBA) were abtained by precipitation method and characterized by EDS, XRD, IR. The relationship between their structure and concentrations ratio of reactants, dry conditions were studied and the catalytic activities of the PBAs were compared. It is found that the main products of oxidation of styrene catalyzed by PBAs are benzaldehyde and styrene oxide. For CuCo PBAs and CuFe PBAs, the influence of the reaction conditions, such as reaction temperature, the time, the solvents, and the oxidants were studied in detail. The results indicate that high conversion of styrene with the selectivity more than50%could be achieved and by-products is less when the CuCoPBAs is used,even under low reaction temperature. Furthermore, after four cyclic catalytic reactions, the conversion of styrene and the selectivity of styrene oxide by CuFePBAs or CuCoPBAs almost kept consant, which showed that CuFe PBAs and CuCoPBAs had good stability. For this reason, we believe that it has the potential for industrial applications.In addition, we also synthesized CoFe PBAs, ZnFe PBAs and NiFe PBAs by the AOT microemulsion method and precipitation method, respectively. The structure and catalytic activities of the PBAs abtained by two method were compared. It is noteworthy that it is more likely to get reduced PBAs with microemulsion method, which show higher catalytic activities than those abtained by precipitation method. More importantly, it is also found that catalytic activities, conversion of styrene and the selectivity of styrene oxide, of NiFePBAs and CoFePBAs are significantly affected by the value of Rw in the microemulsion method.The mechanism of the oxidation of styrene catalyzed by Prussian Blue Analogues were proposed and discussed.