Abstract: The invention relates to an improved process for the preparation of hydrogen peroxide by the anthraquinone process, the improvement being directed at decreasing epoxides in the oxidation stage. According to the invention, the hydrogenated working solution, comprising a 2-alkyl-tetrahydroanthrahydroquinone, is mixed with partly or, preferably, completely oxidized working solution and the mixture is oxidized with a gas comprising oxygen in an oxidation reactor. The volume ratio of hydrogenated to oxidized working solution is in the range from 5 to 1 to 1 to 5 and preferably in the range of 2 to 1 to 1 to 2.

Abstract: A cyclic anthraquinone process for producing hydrogen peroxide using at least two differently substituted 2-alkylanthraquinones and/or their tetrahydro derivatives. The working solution to be used contains (i) at least one reaction carrier from the series 2-(4-methyl-3-pentenyl) anthraquinone (IHEAQ), 2-(4-methylpentyl) anthraquinone (IHAQ) and their di- and tetrahydro derivatives such as, in particular 2-(4-methylpentyl)-.beta.-tetrahydroanthraquinone (THIHAQ), and (ii) at least one reaction carrier from the series of the 2-(C.sub.1 - to C.sub.5)-alkylanthraquinones, especially 2-ethylanthraquinone (EAQ), and their tetrahydro derivatives. The reaction carriers according to (i) make up 5 to 95 molar %, especially 20 to 50 molar % of all reaction carriers. The method is distinguished by greater H.sub.2 O.sub.2 capacity, improved hydrogenation kinetics and lesser susceptibility to disturbances. A method for making THIHAQ is also disclosed.