Preparation Of Porous Carbon Material Supported Nano-Palladium Catalyst And Study On Catalytic Suzuki Reaction

In this paper,nano-palladium catalysts have been successfully synthesized by the protection of various nonionic surfactant and cocoanut active carbon as the carrier.The structure,composition and morphology of the above-prepared catalysts were characterized by TG,XRD,ICP-AES,XPS and TEM.The effects of base,solvent,the amount of catalyst and other conditions on the Suzuki coupling reactions were studied.High dispersed Pd/C catalysts were prepared by the protection of Tween-20.The results of characterization demonstrated that the content of palladium was 8.256�10-5mol/g,the palladium dispersion of the catalysts above-prepared was 10.32%,and the particle size was between 10 and 50 nm.In the Suzuki coupling reactions,the yield of the diphenyl was up to 98.66% when 4-bromoacetophenone and phenylboronic acid reacted for 1 hour at 60? with the amount of 4.10�10-3 mmol catalyst,and the yield of the acetyl biphenyl would be above 89.49% after the catalyst was reused for 3 times.Pd/C catalysts with high dispersion were prepared by the protection of mixd surfactant of Tween-60 and Brij-35.According to the results of characterization,the palladium content was 2.019�10-4 mol/g and the dispersion of Pd in the Pd/C catalysts was 22.19%,the particle size with 5-10 nm was smaller than the nano-palladium synthesized by the protection of Tween-20.The yield of the acetyl biphenyl was up to above 99.72% when the 4-bromoacetophenone and phenylboronic acid reacted for 1hour at 60? with the amount of 3.95�10-3 mmol catalyst,and the yield did not reduce significantly after the catalyst was reused for 4 times.The yield of p-nitrodiphenyl was up to 73.91% when the 4-nitrochlorobenzene and the phenylboronic acid reacted for 12 hours at 80?.