The Preparation Of Pd-g-C₃N₄@AC And Application In Suzuki Cross-coupling Reaction

Palladium is a common catalyst for Suzuki cross-coupling reaction,which plays an important role in medicine and OLED intermediates.Pd/C can not afford highly efficient catalytic activity for Suzuki reaction.So,scientists pay great attentions on modified Pd/C.In this thesis,1,10-phenanthroline and melamine were used as the precursors,respectively,for the preparation of g-C3N4.In method 1,1,10-phenanthroline was first chelated to Pd2+ supported on carbon.Afterward,the complex was calcinated and the pre-catalyst was then reduced by H2,CH20,and NaBH4,respectively.The obtained catalyses were named as Pd-g-C3N4@AC-1-CH2O,Pd-g-C3N4@AC-1-H2,and Pd-g-C3N4@AC-1-NaBH4,respectively.In method 2,melamine was first supported on activated carbon and then calcinated under N2 to give g-C3N4@AC.Afterward,PdCl2 was supported on g-C3N4@AC and reduced by hydrogen to Pd nanoparticles.The obtained catalyst was named as Pd-g-C3N4@AC-2-H2.The cross-coupling of bromoanisole and phenylboronic acid was used for base reaction to select the optimal catalyst and experimental conditions.The optimal experimental condition was as following:the optimal catalyst was Pd-g-C3N4@AC-1-H2(1.5 mol%);the reactions were carried out in DMF/H20 under 60 0C for 4h with K3PO4(3 equiv);the convertion of bromoanisole is 98%.Besides,the catalyst can be reused for 5 times without significant decrease in activity.Expanding experiments were performed under the optimal condition.