The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 23, 1997
Filed:
Nov. 16, 1995
Ube Industries, Ltd., Yamaguchi-ken, JP;
Abstract
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.