| Popis: |
Bismuth oxide, Bi2O3, serves as an oxidant for the conversion of propylene to mainly 1,5-hexadiene. The main secondary product is benzene with small amounts of normal and cyclohexadiene also formed. The formation of 1,5-hexadiene most likely involves the combination of two allylic radicals. As the reaction temperature is increased from 475 to 500 °C, the yield of 1,5-hexadiene decreases while the benzene yield increases. To selectively produce 1,5-hexadiene from propylene, the reaction has to be carried out cyclically, where the propylene reacts with bismuth oxide for a given period of time, and then the oxygen that is consumed is rapidly replenished with air. If a sufficient amount of gas-phase oxygen is used with propylene, the bismuth oxide serves as a catalyst to give a continuous reaction. |
