Study On The Preparation Of Bifunctional MOFs Catalysts And The Technological Conditions Of The Reaction Between CO₂ And Amine

The content of CO2 in the atmosphere is increasing day by day,and the environmental problems and economic losses caused cannot be ignored.As a source of C1,CO2 has great reserves and price advantages.There are more and more reaction routes for the catalytic conversion of CO2,and the research on catalysts is also more and more extensive and in-depth.The N-methylation reaction of CO2 and amine/H2 is a green and economical CO2 conversion route in recent years.The dual-function catalyst can drive the reaction to proceed efficiently,which has guiding significance for the catalytic conversion of CO2.In this paper,Cu/UiO-66(Zr)was prepared,Cu/MIL-101(Cr)was used as a dual-functional catalyst to catalyze the N-methylation reaction of CO2 and aniline/H2.The reaction effect and process conditions of the catalyst were tested by XRD and SEM,HRTEM,FT-IR,XPS,N2 adsorption-desorption,NH3-TPD and other methods to test the physical and chemical properties of the catalyst,the following are the experimental results:(1)Select UiO-66(Zr)as the carrier,and load Ni,Co,Cu non-noble metal nanoparticles to obtain Ni/UiO-66(Zr),Co/UiO-66(Zr),Cu/UiO-66(Zr)Supported dual-function catalyst,according to the experiment Cu/UiO-66(Zr)has the best performance,so Cu/UiO-66(Zr)was selected as the reaction catalyst to carry out a detailed study.It can be seen by observing the electron microscope image Cu nanoparticles are uniformly distributed on the surface of UiO-66(Zr).The particle size of Cu is mostly 3-8 nm.After adjusting the Cu loading ratio and optimizing a series of reaction conditions,the reaction has reached the best effect,1 mmol of aniline and 1 MPa CO2,3 MPa H2,under the catalysis of 4wt%Cu/UiO-66(Zr),reacted at 200℃ for 10 h,the aniline conversion rate(CAN)obtained was 38.4%,and the N-methylaniline The selectivity(SMA)is as high as 95.6%.Even after the catalyst was used 5 times,the CAN did not drop too much,the CAN was 33.1%,and the SMA was almost unchanged.(2)Select MIL-101(Cr)as the carrier,and prepare Cu/MIL-101(Cr)catalysts with different Cu loadings.Characterization data and images show that Cu exists in the form of nanoparticles.Cu nanoparticles are uniformly distributed on the surface of MIL-101(Cr).The particle size of Cu is mostly 3-6 nm.By optimizing Cu/MIL-101 The Cu loading and process conditions of the(Cr)catalyst in the N-methylation reaction of CO2,aniline/H2,have obtained the ideal reaction effect.1 mmol of aniline and 1 MPa CO2,3 MPa H2,catalyzed by 3wt%Cu/MIL-101(Cr),reacted at 200℃ for 10 h,CAN is 52.1%and SMA is 98.5%.After using it continuously for 5 times,the response effect is still good,the CAN is 45.1%,and the SMA was almost unchanged.