N-oxidation of pyridines by hydrogen peroxide in the presence of TS-1

In the production of aromatic N-oxides using the oxidation of N-containing heterocyclic aromatic substrates with H2O2 as oxidant, the non-catalysed ho mogeneous oxidation is found to play an important part in the overall react ion. In addition, when TS-1 is used as a catalyst, there are many potential competitive interactions between the catalyst, the reactants and the produ cts, which limit the effectiveness of the catalyst. It is concluded that th e use of TS-1 and other microporous catalysts for the heterogeneous N-oxida tion of pyridine and substituted pyridines needs to be interpreted with cau tion.