Ube Industries, Inc.

Yukihiro Nishida

Yukio Inaba

Masahiko Watanabe

Yohsuke Ueno

A process for preparing a high purity H.sub.2 O.sub.2 aqueous solution, which comprises the steps of: (a) feeding a crude H.sub.2 O.sub.2 aqueous solution containing H.sub.2 O.sub.2, organic carbon impurities and inorganic impurities into a distillation column having an inner wall at least the surface of which is made of a fluorine resin and internals and packings at least the surface of which are made of a fluorine resin being provided internally of the distillation column, from a bottom portion of the distillation column; (b) subjecting the crude hydrogen peroxide aqueous solution to distillation under reduced pressure and under heating the bottom portion; (c) taking out a distillate containing an extremely low concentration of H.sub.2 O.sub.2 from a top portion of the distillation column without using the distillate for reflux in a distillation operation, and feeding ultra pure water in an amount satisfying (an amount of ultra pure water fed into column top)/((an amount of column top distillate)--(an amount of ultra pure water fed into column top)) being 0.1 to 20 into the top portion of the distillation column; and (d) taking out a H.sub.2 O.sub.2 aqueous solution having a high purity from a middle portion of the distillation column, simultaneously or successively.

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Ube, Japan

Yukihiro Nishida