Synthesis Of Photocatalysts Material Based On MOFs And Its Application In Catalytic Epoxidation Of Propylene

Propylene oxide is the third largest propylene derivative,an important organic intermediate,and also an important chemical raw materials.At present,there are two kinds of preparation methods:chlorohydrin method and co-oxidation method.Chlorohydrin method has large amount of wastewater and waste.Co-oxidation method has many co-products.The development of efficient and green pollution-free propylene oxide preparation method is imperative.The aim of this study was to purify the epoxidation of propylene with oxygen as the oxidant,and to improve the selectivity and formation rate of propylene oxide(PO).It can guidance further study of its industrialization process.In this paper,Ti-MOFs were prepared by solvothermal method.Than TiO2 was prepared by the using Ti-MOFs as precursor.Gold was loaded on the catalyst by impregnation,and the catalyst was applied to photocatalytic epoxidation of propylene.The effects of the reaction temperature,the loading of gold and the type of catalyst on the selectivity of PO and the formation rate were studied.In addition,the mechanism of epoxidation of propylene by Au/TiO2 photocatalysis was also discussed.The results show that TiO2 prepared by Ti-MOFs is porous and has a large specific surface area.Its surface area can reach 245m2g-1.Ti-MOFs have lower epoxidation activity,PO selectivity is only 4.35%.The epoxidation activity of TiO2 prepared by Ti-MOFs is improved,and the PO selectivity can reach 13.79%.Au is well dispersed on the catalyst by impregnation method.When the loading amount of Au is 1%,the epoxidation activity of the catalyst is the best.The most favorable photocatalytic epoxidation,with 66.35?molg-1h-1 highest PO formation rate and 41.04%PO selectivity,was TS-1 photocatalysts under the 6000h-1,C3H6:O2:Ar = 1:1:19 and reaction temperature was 75?.This is mainly due to the reaction of gas phase oxygen in the role of the catalyst to produce atomic oxygen radicals,atomic oxygen radicals and propylene reaction to produce propylene oxide.Au has a plasma resonance effect.The load of Au can separate of photo-generated electrons and holes,which facilitates the gas epoxidation of propylene.