Preparation Of Palladium-based Composite Catalyst And Its Catalytic Study In Suzuki-Miyaura Coupling Reaction

The Suzuki-Miyaura reaction is one of the most important carbon-carbon coupling reactions in the fields of pharmaceuticals,materials,and industrial catalysis.After years of development,it has been widely used in the synthesis of medicines,natural products and materials,and is of great significance to the development of contemporary industry.The palladium?Pd?-based catalyst is the main catalyst of the Suzuki-Miyaura coupling reaction and has a good catalytic effect.However,most Pd-based catalysts are currently expensive to prepare,low in activity,and difficult to separate and recover,limiting their industrial application.Therefore,the development of low-cost Pd-based catalysts with both good catalytic performance and recyclability has become a hotspot in Suzuki-Miyaura coupling reaction research.In this paper,a series of Pd-based composite catalysts were prepared by combining electrospinning technology and high-temperature roasting process,and used to catalyze the Suzuki-Miyaura coupling reaction.The relevant research contents are as follows:1.Pd O-Eu_xO_ycomposite materials were prepared by combining electrospinning technology and high-temperature roasting process.The morphology,structure and composition of the composite catalyst were characterized.The results showed that the catalyst had a fibrous structure,the active materials were evenly distributed,and had good thermal stability.The composite material was used to catalyze the Suzuki-Miyaura coupling reaction,and the results showed that the composite catalyst had excellent catalytic performance.The electronic synergy between Pd O and Eu_xO_yallows the catalyst to efficiently catalyze the Suzuki-Miyaura coupling reaction at a lower temperature and a shorter time.After 10 cycles,the yield of the reaction product can still reach more than 95%,and the composite catalyst can be reused multiple times through simple washing and filtration.The results show that the composite catalyst has good catalytic activity and recycling performance.2.Pd-TiO₂/CNFs composite materials were prepared by methods such as electrostatic spinning technology,high temperature calcination process and hydrothermal treatment.The composite material was characterized,and its morphology,structure,and composition were analyzed.The characterization results showed that the active material was successfully loaded on the carbon nanofibers,the thermal stability of the material was good,and the catalyst was successfully prepared.The composite material can catalyze the Suzuki-Miyaura coupling reaction under low temperature and light,indicating that the catalyst has good photothermal catalytic performance.At the same time,after repeated use of the catalyst for 5 times,better product conversion and selectivity can still be obtained.On the other hand,the recovery method of the composite catalyst is simple and easy to operate,which effectively reduces the loss caused by the recovery process.The composite catalyst can effectively use light energy,and also reflects the use of clean energy,in line with the development of green chemistry.Based on the preparation of Pd-TiO₂/CNFs composite catalyst,urea was used as the nitrogen source to modify the doped nitrogen source to prepare N-Pd-TiO₂/CNFs composite catalyst.The morphology,structure and composition of the composite catalyst were characterized and analyzed.The results showed that the composite material contained a large amount of nitrogen,the active material was successfully loaded on carbon nanofibers,and the thermal stability was good.The composite catalyst was used to catalyze the Suzuki-Miyaura coupling reaction.The results show that the catalyst has excellent catalytic performance.Compared with the Pd-TiO₂/CNFs composite catalyst without nitrogen source,the composite catalyst can effectively reduce the reaction time.At the same time lower the temperature.Nitrogen doping effectively reduces the forbidden band width of TiO₂,makes the use of light energy more efficient,the reaction conditions become milder,and the catalytic efficiency of the catalyst is higher.The catalyst prepared in this paper not only reduces the cost of preparation,but also can effectively improve the activity of the Suzuki-Miyaura coupling reaction,expand its substrate universality,and provide a strong foundation for the application of this reaction in industrial production.