The anthraquinone process, also called the Riedl–Pfleiderer process, is a process for the production of hydrogen peroxide, which was developed by IG Farben in the 1940s.,[1] The industrial production of hydrogen peroxide is based on the reduction of oxygen, as in the direct synthesis from the elements. Instead of hydrogen itself, however, a 2-alkyl-anthrahydroquinone, which is generated before from the corresponding 2-alkyl-anthraquinone by catalytic hydrogenation with palladium is used. Oxygen and the organic phase react under formation of the anthraquinone and hydrogen peroxide. Among other alkyl groups (R) ethyl- and tert-butyl- are used, e.g., 2-ethylanthraquinone.[2] [3]
The hydrogen peroxide is then extracted with water and in a second step separated by fractional distillation from the water. The hydrogen peroxide accumulates as sump product. The anthraquinone acts as a catalyst, the overall reaction equation is therefore:
If ozone is used instead of oxygen, dihydrogen trioxide can be produced by this method.[4]