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).