The invention relates to a method for oxidizing substrates such as hydrocarbons, waxes or soot. The method involves the use of a compound of formula (I) in which: R and R represent H, an aliphatic or aromatic alkoxy radical, carboxyl radical, alkoxycarbonyl radical or hydrocarbon radical, each having 1 to 20 hydrocarbon atoms, SO3H, NH2, OH, F, Cl, Br, I and/or NO2, whereby R and R designate identical or different radicals or R and R can be linked to one another via a covalent bonding; Q1 and Q2 represent C, CH, N, CR , each being the same or different; X and Z represent C, S, CH2, each being the same or different; Y represents O and OH; k = 0, 1, 2; l = 0, 1, 2; m = 1 to 3, and; R represents one of the meanings of R . Said compound is used as a catalyst in the presence of a radical initiator, whereby the molar ratio of the catalyst to the hydrocarbon is less than 10 mol %. Peroxy compounds or azo compounds can be used as the radical initiator. Preferred substrates are aliphatic or aromatic hydrocarbons.