Process for the production of hydrogen peroxide

Process for the production of concentrated aqueous solutions of hydrogen peroxide, comprising the following steps: (a) feeding to a reactor containing a catalyst based on palladium and platinum, heterogeneous and maintained in dispersion in a liquid reaction medium: (i) a liquid stream consisting of an alcohol or a mixture of C1-C3 alcohols or a mixture of said alcohols with water containing at least 50% by weight of alcohol, also containing an acid promoter and a halogenated promoter, the alcohol and optionally all or part of the water contained in the stream being recycled from the subsequent phase d); (ii) a gaseous stream containing hydrogen, oxygen and an inert gas, characterized in that the concentration of the hydrogen is less than 4.5% by volume and the concentration of the oxygen is less than 21% by volume, the complement to 100 being an inert gas; (b) removing from the reactor: (iii) a liquid stream consisting of stream (i) and also containing the hydrogen peroxide and water produced by the reaction, characterized in that the concentration of hydrogen peroxide ranges from 2% to 10% by weight; and (iv) a gaseous stream essentially consisting of non-reacted hydrogen and oxygen and the inert gas, (c) optionally adding to (iii) water in such a quantity so that its content is at least equal to that of the final aqueous solution of hydrogen peroxide; (d) sending the stream deriving from (c) to a system consisting of one or more evaporators or distillation columns from which the following are removed: (v) one or more streams containing all the alcohol and possibly water, which are recycled to (a); (vi) a concentrated aqueous solution of H2O2 at a concentration ranging from 15 to 60% by weight; (vii) optionally a stream containing the water fed in excess in (c).