Hydrogen peroxide H2O2

Hydrogen peroxide, better known as hydrogen peroxide, is a colorless liquid used mainly as a pulp and textile fiber bleaching agent (oxidizer) and as a synthesis intermediate.

French chemist Thénard identified hydrogen peroxide (H ₂ O ₂ ) in 1818 following experiments on barium peroxide. This discovery gave rise to the first industrial method of preparing hydrogen peroxide, between 1870 and 1880.

From 1910 onwards, the electrolytic process supplanted the BaO ₂ process. Hydrogen peroxide is then produced by electrolysis of sulfuric acid or ammonium hydrogen sulfate with anodic oxidation, followed by hydrolysis of the peroxodisulfuric acid H ₂ S ₂ O ₈ or ammonium peroxodisulfate formed. Developments in distillation techniques then enable more concentrated and stable solutions to be produced.

The alkylanthraquinone auto-oxidation process discussed here was developed during the last world war. Almost all of the world's hydrogen peroxide production (capacity close to 2.5 Mt/year) is based on this process, as the processes mentioned above have completely disappeared. A costly process in terms of investment, it is the only one that enables the production of concentrated hydrogen peroxide (> 40% by mass at the end of the organic cycle) at a competitive cost.

A unit was built in the early 1990s based on a cathodic oxygen reduction process: the peroxide produced, however, is of low concentration (30 - 40 g/L).

Various processes have been patented for directly combining H ₂ and O ₂ , including aqueous synthesis on platinum-group metal complexes. However, none of these processes has yet led to industrial implementation.