The present invention relates to a method for the preparation of hydrogen peroxide through a continuous process, extracting hydrogen peroxide produced from reduction and oxidation of a working solution and recycling the oxidized working solution back to the reduction process, wherein the composition of the working solution, i.e. the composition of 2-alkylanthraquinone and 2-tetrahydroalkylanthraquinone, is optimized to increase the solubility of the quinones and to improve the reaction rate. The working solution comprises 2-alkylanthraquinone, 2-tetrahydroalkylanthraquinone and an organic solvent, wherein 65-95 mol % of the alkyl group of 2-alkylanthraquinone and 2-tetrahydroalkylanthraquinone is amyl and the remaining 5-35 mol % of the alkyl group is ethyl, and the molar ratio of 2-alkylanthraquinone to 2-tetrahydroalkylanthraquinone is from 4:6 to 1:9.