Mitsubishi Gas Chemical Company, Inc.

Sekisui Plastics Co., Ltd.

Nissin Food Products Co., Ltd.

Hiroshi Hasegawa

Isao Hagiwara

Katsuhiro Iura

Motoharu Takeuchi

Hisashi Sakaitani

Toru Yoshimi

Masaru Chiba

Yukako Kozawa

Shinjiro Sawamoto

Hisashi Matsuda

Yasuhiro Ono

Akio Tsujita

Hirotomo Iwasaki

In the production of hydrogen peroxide, when ketone forms are increased upon conversion from higher alcohol components in organic solvents, such increased levels of ketone forms reduce the water content in a working solution and lead to deterioration of catalytic activity. Moreover, increased levels of ketone forms reduce the solubility of anthrahydroquinone compounds and may cause an obstacle to stable and safe operation in the production of hydrogen peroxide due to crystallization and deposition of the anthrahydroquinone compounds. The object of the present invention is to provide a process in which polar solvent-derived altered substances (ketone forms) in a working solution provided for use in the production of hydrogen peroxide via the anthraquinone process are regenerated into the original alcohol components to thereby improve the production efficiency of hydrogen peroxide. From a working solution which has been used for many years, organic solvent components containing ketone forms are separated by distillation and hydrogenated in the presence of a metal catalyst to regenerate the organic solvent components into the original alcohol components, whereby hydrogen peroxide can be produced more efficiently.

Method for regenerating working solution used for production of hydrogen peroxide and method for producing hydrogen peroxide using regenerated working solution

A method for producing hydrogen peroxide by an anthraquinone process includes the steps of: reducing with hydrogen a working solution containing an organic solvent and anthraquinone in the presence of a hydrogenation catalyst; and activating the hydrogenation catalyst when a hydrogenation selectivity has decreased due to repeated use, wherein the catalyst activation step includes a step of treating the hydrogenation catalyst with a first alkaline aqueous solution of pH 10 or above containing an alkali metal, and then washing the treated hydrogenation catalyst with water or a second alkaline aqueous solution that is more weakly alkaline than the first alkaline aqueous solution so as to set a catalyst soak solution comprising 5 parts by weight of pure water in admixture with 1 part by weight of the activated hydrogenation catalyst to a pH of 8.0 or above.

Method for activating hydrogenation catalyst and method for producing hydrogen peroxide including same

The present invention provides a method for producing hydrogen peroxide, comprising the steps of: alternately reducing and oxidizing a working solution containing anthraquinone compounds as a reaction medium, wherein a mixture of alkyl-substituted anthraquinones and alkyl-substituted tetrahydroanthraquinones in a molar ratio of from 2:1 to 8:1 is used as the anthraquinone compounds in the working solution, in the reduction step all of the tetrahydroanthraquinones and some or all of the anthraquinones in the working solution are reduced; and keeping the content of alkyl-substituted anthrahydroquinones in the working solution after the reduction step and before the oxidation step higher than the content of alkyl-substituted tetrahydroanthrahydroquinones, wherein ethylanthraquinone and ethyltetrahydroanthraquinone are used as anthraquinone compounds in the working solution in a total proportion of both of from 10 to 45 mol % of all of the anthraquinone compounds in the working solution.

Method for producing hydrogen peroxide

Process and apparatus for manufacturing a foamed resin container with a

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Ibaraki, Japan

Hiroshi Hasegawa