| Ethylene oligomerization is an important petrochemical reaction that ethylene can be converted into high value-added linear alpha-olefins.As ethylene oligomerization catalysts,bulk MOFs have the advantage of selectively catalyzing ethylene,but their catalytic activity is low.In this thesis,the modification of MOFs was used to improve their ethylene oligomerization catalytic activity.Firstly,by adding polyvinylpyrrolidone（PVP）during the synthesis of ZIF-67,the effect of different amounts of PVP on the number of metal coordination unsaturated sites in the structure of ZIF-67 was studied,and then its ethylene oligomerization properties were investigated.Secondly,the specific surface area and metal valence state of MIL-101（Fe）were regulated by vanillin,and the ethylene oligomerization properties of vanillin-modified MIL-101（Fe）were studied.Finally,using MIL-101（Fe）as a carrier,Ag（I）was loaded on the surface of MIL-101（Fe）by ultrasonic method,and the ethylene oligomerization activity was improved through the strong adsorption affinity of Ag（I）to ethylene.The results show that under the action of the cocatalyst Et2AlCl,the activities of the modified MOFs are improved,and the selectivity of C4 is basically unchanged.After the PVP modification,N-Co bonds in ZIF-67 decreased from 75.39%to 62.78%.The activity of ethylene selective dimerization is increased from 0.41×105 g/mol·h to 0.90×105g/mol·h,and the selectivity is reduced from 90.25%to 85.19%.After the vanland is modified,the specific surface area increased from 936 m2/g to 2239 m2/g,Fe2+increased from 16.32%to 29.49%.The activity of ethylene selective dimerization is increased from0.81×105 g/mol·h to 1.24×105 g/mol·h,and selectivity increased from 90.25%to 92.34%.MIL-101（Fe）load Ag（I）enhances adsorbent affinity with ethylene.The activity of ethylene selective dimerization is increased from 0.81×105 g/mol·h to 1.59×105 g/mol·h,and selectivity increased from 90.25%to 92.12%. |
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