Regeneration method of working solution
A regeneration method of a working solution is herein disclosed in which various by-products which do not participate in the production of hydrogen peroxide and which are present in the working solution in a hydrogen peroxide production process utilizing an anthraquinone method can efficiently be converted into anthraquinones effective as reaction media for the production of hydrogen peroxide.The present invention is concerned with (1) a regeneration method of a working solution wherein at least a part of the unreduced working solution is brought into contact with a catalyst mainly comprising a .gamma.-alumina at a temperature of 40 to 150.degree. C., and (2) another regeneration method of a working solution wherein the working solution is brought into contact with a catalyst mainly comprising a .gamma.-alumina at a temperature of 20 to 150.degree. C. under conditions that a concentration h (mol/liter) of the alkyltetrahydroanthrahydroquinones in the working solution before the catalytic treatment meets the equation(0.0018.times.t-0.0285).times.h<0.05WHEREIN t is a treatment temperature (.degree.C.), to convert alkyltetrahydrooxyanthrones in the working solution into the alkyltetrahydroanthrahydroquinones.
Claims
1. A method for regenerating a working solution containing an anthraquoinone dissolved in at least one solvent selected from the group consisting of trimethylbenzene and diisobutylcarbinol, from a process for producing hydrogen peroxide by repeatedly reducing and oxidizing the working solution, wherein the antraquinone in the working solution comprises at least one alkyltetrahydroanthraquinone selected from the group consisting of amyltetrahydroanthraquinone, ethyltetrahydroanthraquinone and t-butyltetrahydroanthraquinone, the method comprising bringing the working solution into contact with a catalyst comprising a.gamma.-alumina and having a particle size of 8 to 100 mesh at a treatment temperature of 20.degree. to 150.degree. C. under conditions that a concentration h (mol/liter) of the at least one alkyltetrahydroanthrahydroquinone in the working solution before the contact with the catalyst satisfies the following equation:
2. The method according to claim 1 wherein the concentration h (mol/liter) of the at least one alkyltetrahydroanthrahydroquinone in the working solution before the contact with the catalyst is 0.15 mol/liter or less and satisfies the following equation:
3. The method according to claim 1, wherein the catalyst has a particle size of 8 to 100 mesh.
4. The method according to claim 3, wherein the method is carried out in a stirrer-equipped reactor, a fixed bed reaction or a fluidized bed reactor.
5. The method according to claim 1, wherein the working solution which is brought into contact with the catalyst comprises amyltetrahydroanthraquinone and amyltetrahydrooxyanthrone.
6. The method according to claim 5, wherein said at least one solvent comprises 1,2,4-trimethylbenzene and diisobutylcarbinol.
7. The method according to claim 6, wherein the treatment temperature is 60.degree. C.
8. The method according to claim 6, wherein the treatment temperature is 100.degree. C.
9. The method according to claim 6, wherein the treatment temperature is 120.degree. C.
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Type: Grant
Filed: Mar 26, 1997
Date of Patent: Feb 2, 1999
Inventors: Kazuharu Ogasawara (Kamisu-machi, Kashima-gun, Ibaraki-ken), Tomio Kato (Katsushika-ku, Tokyo), Kazuyuki Minato (Katsushika-ku, Tokyo), Kenji Kato (Katsushika-ku, Tokyo), Makoto Sumitani (Katsushika-ku, Tokyo)
Primary Examiner: Charles T. Jordan
Assistant Examiner: Meena Chelliah
Application Number: 8/829,696
International Classification: C07D 5018;