Preparation Of Modified Mofs Catalyst And The Study Of Application In Methanol Liqued-phase Oxidation

As one of the important chemical raw materials,methanol is facing the problem of excess production capacity.One-step oxidation of methanol to produce methyl formate is not only an important way to solve the contradiction between supply and demand of methanol,but also a greener method compared with the traditional method for preparing methyl formate.We choose MIL-53,one of metal-organic frameworks(MOFs)as carriers.By loading the precious metals,catalysts of Pd/MIL-53,Au/MIL-53,Pd-Au/MIL-53 and Pd-Ru/MIL-53 were obtained.These catalysts were characterized by XRD,BET,TEM,FT-IR and used in the methanol liquid-phase oxidation to test their activity.The results are as follow:(1)In the single-metal catalyst system,Au and Pd remained zero valence after loading,and the nanoparticles were about 5.0nm.The overall structure of the carrier MIL-53 is stable and the specific surface area can reach 1346 m2/g.Under the optimal reaction conditions for using the 2.0wt%Au/MIL-53 catalysts,the conversion of methanol can reach 26.61%,and the selective of methyl formate can reach 66.08%.Under the optimal reaction conditions for using the 0.6wt%Pd/MIL-53 catalysts,the conversion of methanol can reach 54.87%,and the selective of methyl formate can reach 66.90%.(2)In a bimetallic catalyst system,the structure and material of carrier was not changed before and after loading.The loaded bimetallic nanoparticles size was about 6.0nm.Pd,Au and Ru particles maintained zero valence after loading.Under the optimal reaction conditions of Pd/MIL-53 catalyst,0.6wt%Pd-0.6wt%Ru/MIL-53 catalyst can make the conversion of methanol to reach 39.70%,the selective of methyl formate can reach 78.86%.And 0.6wt%Pd-1.0wt%Au/MIL-53 catalyst can make the conversion of methanol get to 57.55%,and the selectivity of methyl formate can reach 70.66%.