Mitsubishi Gas Chemical Company, Inc.

Yukio Ishiuchi

Hiromitsu Nagashima

Yasushi Hiramatsu

Michiya Kawakami

Takeshi Tomita

Yasuhisa Kuriyama

Junichiro Sugano

Tomio Kato

Kazuharu Ogasawara

Hiroshi Takamiya

Kazuyuki Minato

Yoshitugu Minamikawa

A process for producing hydrogen peroxide by subjecting a working solution containing anthraquinones as the reaction medium, to reduction and oxidation alternately, which process is characterized in that (1) the anthraquinones as the reaction medium contained in the working solution are a mixture of an alkyl-substituted anthraquinone and an alkyl-substituted tetrahydroanthraquinone, (2) in the reduction step, the total amount of the alkyl-substituted tetrahydroanthraquinone in the working solution and part or the total amount of the alkyl-substituted anthraquinone in the working solution are reduced, and (3) in the working solution after the reduction step, the content of the alkyl-substituted anthrahydroquinone formed is kept higher than the content of the alkyl-substituted tetrahydroanthrahydroquinone formed.

Process for producing hydrogen peroxide

This invention provides a process for producing hydrogen peroxide through catalytic reaction of oxygen with hydrogen in an aqueous medium in the presence of a platinum group metal catalyst, in which an organic solvent having only limited solubility with water and less hydrogen peroxide-dissolving ability compared to that of water is caused to be concurrently present in the reactor, and oxygen and hydrogen are catalytically reacted in an aqueous medium in the presence of a water- and organic solvent-insoluble, hydrophilic platinum group metal catalyst, under a low reaction pressure, to form high concentration aqueous hydrogen peroxide solution within a short time.

The present invention provides a process for producing hydrogen peroxide by reacting oxygen and hydrogen in a reaction medium catalytically using, as a catalyst, a tin-modified platinum group metal supported on a carrier. In the process using said catalyst, the presence of halogen and acid in reaction medium is unnecessary unlike the prior art methods, and hydrogen peroxide of high concentration can be produced efficiently. Thus, the present process has no restriction for reactor material as seen the prior art methods and further allows for easy purification of produced hydrogen peroxide.

A method for producing a high concentration of hydrogen peroxide by reacting oxygen and hydrogen directly in a neutral reaction medium that contains a promoter comprising a halogen containing compound, which halogen containing compound contains at least one halogen other than fluorine, at a reaction temperature in the range of from 0.degree. to 50.degree. C. and at a reaction pressure in the range of from 3 to 150 kg/cm.sup.2 .multidot.G in the presence of a platinum group metal catalyst supported on a catalyst carrier containing a heteropolyacid that has been made insoluble in water or a platinum group metal catalyst supported on a catalyst carrier comprising activated carbon that is supporting a heteropolyacid.

Method for producing hydrogen peroxide

Oxygen and hydrogen are catalytically reacted in an acidic reaction medium in the presence of a platinum group metal catalyst to prepare hydrogen peroxide using as a carrier for the platinum group metal catalyst a composite oxide containing cerium. The process need not halogen ions in the acidic reaction medium and enables preparation of hydrogen peroxide in high concentration on an industrial scale advantageously.

Process for the preparation of hydrogen peroxide

A method for producing a high concentration of hydrogen peroxide by reacting oxygen and hydrogen directly in a reaction medium containing a promoter such as a halogen containing compound using a platinum group metal catalyst supported on a solid acid carrier or a solid super acid carrier.

This invention provides a method for high efficiency, high concentration production of hydrogen peroxide wherein oxygen and hydrogen are reacted in the reaction medium in the presence of a catalyst comprising a metallic or carrier supported platinum group metal catalyst onto which an organic halogen compound which is insoluble in water, which compound excludes compounds which contain no halogen other than fluorine, has been adsorbed or a platinum group metal catalyst supported on a carrier in which a halogenated organic compound, which compound excludes compounds that contain no halogen other than fluorine, has been adsorbed to the carrier prior to supporting the platinum group metal. Since it is not necessary for halogen ions to be present in the reaction medium as it was in the prior art, the problems of deterioration due to the dissolution of the catalyst and of corrosion of the structural materials of the reaction vessel are alleviated.

A method for producing hydrogen peroxide by the reaction of hydrogen and oxygen in the reaction medium in the presence of a platinum group metal catalyst supported on a halogenated resin, in which, since there are no halogen ion nor high concentrations of acid in the reaction medium of this invention as there are in prior art methods, the problems of dissolution of catalyst and corrosion of the reaction vessel are solved.

A process for producing quinones corresponding to anthracenes or alkylnaphthalenes in high yields and selectivities, which comprises reacting the anthracenes or alkylnaphthalenes with hydrogen peroxide in the liquid phase in the presence of hydrogen chloride as a catalyst. Methanol, for example, may be used as a reaction medium.

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Ushiku, Japan

Yukio Ishiuchi