Au- and Ag-loaded MnO2 nanostructures supported on nitrogen- and nitrogen-sulfur-doped pyroproteins: Synthesis and catalytic activity in organic transformations

Four novel Au-and Ag-loaded MnO2 nanostructures supported on nitrogen-doped pyroprotein of natural silk (Au-MnO2@PPNS and Ag-MnO2@PPNS) and nitrogen-sulfur-doped pyroprotein of natural wool (Au-MnO2@PPNW and AgMnO2@PPNW) have been synthesized. Nitrogen-and nitrogen-sulfur-doped pyroproteins were prepared by carbonization of natural silk and wool proteins, respectively. The catalysts were investigated for the aerobic oxidation of aromatic hydrocarbons of petroleum naphtha and the aerobic oxidative synthesis of 2-phenylbenzo[d]thiazoles, 2-phenyl-1H-benzo[d]imidazoles and 2-phenyl-4-quinazolinones in the absence of any co-promoter and additional oxidizing reagent. The prepared catalytic systems showed higher catalytic activity in comparison to aggregated catalysts.