Preparation Of MOFs Derivatives Based On 2,2′-Bipyridine Catalysts And Their Performance

As an important modern industrial raw material and pharmaceutical intermediate,2,2’-bipyridine has been widely used in many fields such as pesticides,pharmaceuticals,and thermostable coatings,and as an important synthetic intermediate for pesticide diquat.External demand for 2,2’-bipyridine is increasing.The current industrial route for the synthesis of 2,2’-bipyridine is mainly Ullmann coupling reaction using 2-halopyridine as a raw material.Due to the presence of the halogen element,the synthetic route will remove halogen during the coupling reaction.It causes a large three waste problem,and the synthesis route has problems such as low conversion of 2,2’-bipyridine,high catalyst cost,and complicated synthesis route.Compared with the synthesis of 2,2’-bipyridine from 2-halopyridine through the Ullmann coupling reaction,the synthetic route of 2,2’-bipyridine directly from pyridine as a raw material is greener and environmentally friendly,and has a higher Atomic utilization.At present,the direct coupling method of pyridine to synthesize 2,2’-bipyridine mainly uses anhydrous Raney Ni as a catalyst,and often uses a fixed-bed reactor to continuously produce 2,2’-bipyridine.However,Raney Ni is producing and There are a series of problems during use,which are easily oxidized and there is a danger of explosion.Based on the ordered porous metal oxide support derived from the pyrolysis of MOFs materials,this thesis prepared an effective catalyst for the direct coupling of pyridine to 2,2’-bipyridine catalyst.The main research contents and results are as follows:（1）A novel nano-sized spherical Al-MOF was synthesized by a simple hydrothermal method.An ordered porous Al₂O₃ support was prepared based on the pyrolysis derivative of Al-MOF,and the active center components Ni and auxiliaries were loaded by the impregnation method.Ni/Al₂O₃,Ni-Na/Al₂O₃,Ni-Ce/Al₂O₃ and Ni-Na-Ce/Al₂O₃ catalysts were prepared from the catalyst metals Na and Ce.The microstructure of the catalyst was analyzed by SEM,TEM,XRD,BET,XPS and H₂-TPR.Appearance and structural characteristics.In addition,the performance of Ni/Al₂O₃,Ni-Na/Al₂O₃,Ni-Ce/Al₂O₃ and Ni-Na-Ce/Al₂O₃ catalysts was evaluated and compared.The experimental results show that Ni-Ce/Al₂O₃ shows the best catalytic activity and stability,showing the highest activity at 2 h（the yield of 2,2’-bipyridine is9.5%）,and when the catalysis is carried out to 30 h,the yield of 2,2’-bipyridine was still 1.5%.At the same time,the effects of the reaction pressure and reaction temperature on the catalytic activity of Ni-Ce/Al₂O₃ catalytic performance evaluation reactions were explored.（2）Based on the synthesis process of the synthesized Al-MOF,by adjusting the proportion of raw materials for the synthesis of Al-MOF,and exploring the appropriate proportion of cerium nitrate hexahydrate as the Ce source,a nano-sized spherical bimetallic Al/Ce-MOF was developed.Based on the thermal decomposition of Al/Ce-MOF,CeO₂-Al₂O₃ support with spherical morphology was derived,and Ni/CeO₂-Al₂O₃and Ni-Na/CeO₂-Al₂O₃ catalysts were prepared by impregnating the active center component Ni and the auxiliary metal Na.The microstructure,structure and characteristics of catalyst and the content and distribution of elements were analyzed by SEM,TEM,XRD,EDS,ICP,BET,XPS and H₂-TPR.In addition,using Ni/CeO₂-Al₂O₃ as a control sample,compared with the catalytic performance with Ni-Na/CeO₂-Al₂O₃ catalyst doped with basic metal Na in the catalyst and Ni-Ce/Al₂O₃ catalyst based on ordered porous Al₂O₃ support,the results show that Ni/CeO₂-Al₂O₃ shows a higher catalytic activity It showed the highest activity at 4 h（the yield of 2,2’-bipyridine was12.5%）,and the yield of 2,2’-bipyridine was still 1.89%at 30 h.And further explored the reaction pressure of Ni/CeO₂-Al₂O₃ catalytic performance evaluation reaction and the influence of reaction temperature on catalytic activity.