Metal-Free Nitrogen- and Boron-Codoped Mesoporous Carbons for Primary Amides Synthesis from Primary Alcohols via Direct Oxidative Dehydrogenation

Abstract

Metal-free catalysts show environmental friendliness and cost-effectiveness, as well as less susceptibility to poisoning over metal and metal oxide catalysts. In this respect, we present the synthesis and characterization of metal-free mesoporous nitrogen- and boron-codoped nanocarbon (meso-N,B/C), which exhibits good catalytic performance with conversion of 89% and selectivity of 83% toward amide synthesis from primary alcohols using NH4OAc as an ammonia resource under an oxygen atmosphere. The facile codoping synthetic strategy was executed by pyrolysis of nitrogen-enriched ligand 4,5-diazafluorene-9-one azine (DAA) and H3BO3 as a nitrogen and boron content modulator, respectively. Significantly, control experiments revealed that the reaction proceeded through direct oxidative dehydrogenation of hemiaminal after aldehyde-ammonia condensation, which was remarkably different from that in the previous literature. Density functional theory (DFT) calculations further demonstrate that the selective preference...