Use of an aqueous solution of hydrogen peroxide

Use of an aqueous solution of hydrogen peroxide having a concentration of hydrogen peroxide [H2O2] expressed as% by weight of the solution and an apparent pH of pH min to pHmax, such that pH min> = 3.45 to 0, 0377 x [H2O2] pHmax> = 3.76 to 0.0379 x [H2O2] for the manufacture of propylene oxide or epichlorohydrin by reaction between propylene or allyl chloride and hydrogen peroxide.