WO2012074118A1

WO2012074118A1 - Method for producing olefin oxide

Info

Publication number: WO2012074118A1
Application number: PCT/JP2011/077998
Authority: WO
Inventors: Hideo Kanazawa
Original assignee: Sumitomo Chemical Co Ltd
Current assignee: Sumitomo Chemical Co Ltd
Priority date: 2010-11-29
Filing date: 2011-11-28
Publication date: 2012-06-07
Anticipated expiration: 2013-05-29
Also published as: JP2012116758A

Abstract

Disclosed is a method for producing an olefin oxide, capable of overcoming the disadvantage of the conventional methods that hydrogen peroxide is not completely consumed and thus is left to remain, depending on the reaction conditions. To solve this problem, the method of the present invention comprises the steps of [1] reacting hydrogen peroxide with an olefin in the presence of a titanosilicate and a solvent, and [2] bringing the reaction product obtained in the previous step, into contact with a substance containing at least one element selected from the group consisting of manganese and platinum group elements.

Description

DESCRIPTION

METHOD FOR PRODUCING OLEFIN OXIDE

[0001]

Technical Field

The present application is filed claiming the priority of Japanese Patent Application No. 2010-264841 filed on November 29, 2010 under the Paris Convention, the entire content of which is incorporated herein by reference.

The present invention relates to a method for

producing an olefin oxide.

[0002]

Background Art

As a method for producing an olefin oxide such as propylene oxide, there is known, for example, a method of reacting an olefin such as propylene or the like with hydrogen peroxide in the presence of a titanosilicate and a solvent (cf., Non-Patent Document 1).

[0003]

Non-Patent Document 1: Direct Synthesis of Propylene Oxide Using Modified Titanosilicate Catalyst, by Hiroaki Abekawa and Masaru Ishino, the 89th Catalyst Symposium, Preliminary Papers for Symposium A, March 20, 2002, page 65, 2P13

[0004]

Summary of the Invention The above-described production method, however, has a problem in that hydrogen peroxide is not completely

consumed and thus is left to remain, depending on

conditions for the reaction.

[0005]

As a result of the present inventors ' intensive studies under such a situation, the present invention is accomplished. The present invention provides the following <1> A method for producing an. olefin oxide, comprising the steps of

[1] reacting hydrogen peroxide with an olefin in the presence of a titanosilicate and a solvent, and

[2] bringing the reaction product obtained in the previous step into contact with a substance containing at least one kind of element selected from the group consisting of manganese and platinum group elements.

<2> The method defined in the paragraph <1>, wherein the. solvent is a mixed solvent of an organic solvent and water. <3> The method defined in the paragraph <2>, wherein the organic solvent is acetonitrile .

[0006]

<4> The. method defined in any one of the paragraphs <1> to <3>, wherein the titanosilicate is a layer titanosilicate having ring-structural pores each containing 12 or more oxygen atoms . <5> The method defined in any one of the paragraphs <1> to <4>, wherein the titanosilicate is a Ti-MWW precursor.

[0007]

<6> The method defined in any one of the paragraphs <1> to <5>, wherein the substance is a compound containing

manganese or a platinum group element, or a simple

substance containing a platinum group element.

<7> The method defined in any one of the paragraphs <1> to <5>, wherein the substance is manganese dioxide.

<8> The method defined in any one of the paragraphs <1> to <5>, wherein the substance contains at least one kind of element selected from the group consisting of rhodium, palladium, iridium and platinum.

<9> The_. method defined in any one of the paragraphs <1> to <5>, wherein the substance contains palladium or platinum..

[0008]

<10> The method defined in any one of the paragraphs <1> to <9>, wherein the substance is supported on a carrier..

<11> The method defined in the paragraph <10>, wherein the carrier is activated carbon.

[0009]

<12> A method for removing hydrogen peroxide, comprising a step of bringing a substance which contains at least one kind of element selected from the group consisting of manganese and platinum group elements, into contact with a solution which contains an olefin oxide, hydrogen peroxide and a solvent.

[0010]

According to the production method of the present invention, an olefin oxide containing less residual

hydrogen peroxide can be provided.

[0011]

Brief Description of Drawings

Fig. 1 shows an embodiment of an olefin oxide- producing apparatus according to the present invention.

[0012]

Description of Embodiments

The present invention. provides a method for producing an olefin oxide, comprising the . steps of [1] reacting hydrogen peroxide with an olefin in the presence of a titanosilicate and a solvent (hereinafter optionally referred to as the reaction step), and [2] bringing the reaction product obtained in the previous step into contact with a substance containing at least one kind of element , selected from the group consisting of manganese and

platinum group elements (hereinafter optionally referred to as the present substance) (hereinafter optionally referred to as the contact step) .

[0013]

The olefin for use in the reaction step means alkene, cycloalkene, a compound obtainable by optionally

substituting a hydrogen atom in alkene with a substituent, or a compound obtainable by optionally substituting, a hydrogen atom in cycloalkene with a substituent.

Examples of the substituent include a hydroxyl group, a halogen atom, a carbonyl group, an alkoxycarbonyl group, a cyano group, a nitro group, etc.

Examples of the olefin include C2 -C10 alkenes, C4-C10 cycloalkenes, etc.

Specific examples of the C2 -C10 alkenes include

ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, 2-butene, isobutene, 2-pentene, 3- pentene, 2-hexene, 3-hexene, 4-methyl-l-pentene, 2-heptene, 3-heptene, 2-octene, 3-octene, 2-nonene, 3-nonene, 2-decene and 3-decene.

Specific examples of the C4-C10 cycloalkenes include cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene and cyclodecene.

A more preferable olefin is propylene.

[0014]

As the propylene, there is exemplified propylene which is produced by, for example, thermal cracking, catalytic cracking of heavy oils, or methanol-catalytic reforming. As the propylene, there may be used purified propylene or crude propylene which is not undergone a purification step. A preferable purity of propylene is, for example, 90% by volume or more, more preferably 95% by volume or more. Examples of the impurity contained in propylene include propane, cyclopropane, methyl acetylene, propadiene, butadiene, butane, butene, ethylene, ethane, methane and hydrogen .

[0015]

An amount of the olefin to be used in the reaction step may be controlled according to the kind of the olefin, the reaction conditions, etc., and it is preferably at least 0.01 part by weight, more preferably at least 0.1 part by weight, per total 100 parts by weight of a solvent for use in the reaction step.

[0016]

The olefin to be used in the present invention may be, for example, in a state of either a gas or a liquid.

Examples of the olefin in a liquid state include a liquid of an olefin alone and a mixed liquid of an olefin

dissolved in an organic solvent or a mixed solvent of an organic solvent and water. Examples of the olefin in a gaseous state include a gaseous olefin and a mixed gas of a gaseous olefin with other gas components such as a nitrogen gas and a hydrogen gas.

[0017]

The titanosilicate for use in the reaction step is obtained, for example, by substituting a part of Si of a porous sililcate (Si0₂) with Ti. Ti in the titanosilicate is inside the skeleton of Si0₂, which can be easily

confirmed by the UV visible spectrum in which a peak

appears within a range of from 210 to 230 nm. Ti in Ti0₂ is usually hexahedrally coordinated, while Ti in the

titanosilicate is tetrahedrally coordinated. Thus, the coordination structure can be readily confirmed by

measuring a coordination number by XAFS analysis of

titanium K-shell.

[0018]

Examples of the titanosilicate include crystalline titnosilicates, layer titanosilicates, mesoporous

titanosilicates, etc.

Examples of the crystalline titanosilicate include TS-

2 having a MEL structure, Ti-ZSM-12 having a MTW structure (for example, Zeolites 15, 236-242, (1995)), Ti-Beta having a BEA structure (for example, Journal of Catalysis 199, 41- 47 (2001)), Ti-MWW having a MWW structure (for example, Chemistry Letters, 774-775, (2000)), Ti-UTD-1 having a DON structure (for example, Zeolites 15, 519-525, (1995)), etc., which are identified in the structure codes of

International Zeolite Association (IZA).

Examples of the layer titanosilicate are

titanosilicates having MWW structures whose interlayers are expanded, such as a Ti-MWW precursor (for example, those listed in JP-A-2003-32745) and Ti-YNU-1 (for example, those listed in Angewandte Chemie International Edditiori 43, 236- 240, (2004)),.

The mesoporous titanosilicate means a titanosilicate having regular pores with pore sizes of 2 to 10 nm, and examples thereof include Ti-MCM-41 (for example,

Microporous Materials 10, 259-271, (1997)), Ti-MCM-48 (for example, Chemical Communications 145-146, (1996)), Ti-SBA- 15 (for example, Chemistry of Materials 14, 1657-1664, (2002)), etc.

Further, a titanosilicate having both features of the mesoporous titanosilicate and titanosilicate zeolite such as Ti-MMM-1 (for example, Microporous and Mesoporous

Materials 52, 11-18, (2002)) is also included in these examples.

[0019]

As the titanosilicate for use in the reaction step, a crystalline titanosilicate or layer titanosilicate, which has ring structural pores each containing 12 or more oxygen atoms is preferable. Examples of the crystalline

titanosilicate which has ring structural pores each

containing 12 or more oxygen atoms are- Ti-ZSM-12, Ti-Beta, Ti-MWW and Ti-UTD-1. Examples of the layer titanosilicate which has ring structural pores each containing 12 or more oxygen atoms are Ti-MWW precursors and Ti-YNU-1. Among these, Ti-MWW and the Ti-MWW precursors are more preferable.

[0020]

Preferably, the titanosilicate for use in the reaction step is prepared by hydrolyzing a titanium compound and a silicon compound, using a structure-directing agent;

optionally subjecting the hydrolyzed product to a

hydrothermal synthesis to thereby improve its crystallinity, layer structure or pore regularity; and calcining or

extracting the product to remove the structure-directing agent.

Specifically, a boron compound, a silicon compound and a structure-directing agent are mixed in a sealed reactor such as an autoclave, and the mixture is heated and

pressurized at a temperature of from 0 to 250°C, preferably from 50 to 200°C under a gauge pressure of from 0 to about 10 MPa, to obtain a Ti-MWW precursor, which is then

separated by filtration. If needed, the separated Ti-MWW precursor is washed with water or the like. This washing may be optionally controlled by adjusting an amount of a washing liquid or a pH of a washing filtrate. The Ti-MWW precursor prepared as above is further calcined at a

temperature of from 500 to 800° to dehydration-condense the interlayer of the same precursor. Thus, Ti-MWW is obtained. The Ti-MWW may again be heated and pressurized at a temperature of from 0 to 250°C, preferably from 50 to 200°C under a gauge pressure of from 0 to about 10 MPa. This titanosilicate obtained by this method is again formed into a Ti-MWW precursor.

[0021]

The structure-directing agent has an ability to form a zeolite having a MWW structure. Examples of the structure- directing agent include piperidine, hexamethyleneimine, adamantyltrimethylammonium salts (for example,

adamantyltrimethylammonium hydroxide and

adamantyltrimethylammonium iodide) , and octyltrimethylammonium salts (for example, octyltrimethylammonium

hydroxide and octyltrimethylammonium bromide) . Any of these compounds may be used alone, or two more kinds selected therefrom may be used as a mixture in optional ratio.

Among these, preferable structure-directing agents are piperidine and hexamethyleneimine.

The structure-directing agent is used in an amount of, for example, from 0.001 to 100 parts by weight, preferably from 0.1 to 10 parts by weight, per total one part by weight of the boron compound and the silicon compound.

[0022]

Examples of the titanium compound include titanium alkoxides such as tetra-n-butylorthotitanate; peroxytitanates such as tetra-n-butylammonium

peroxytitanate; titanium halides such as titanium

tetrachloride; and titanium compounds such as titanium acetate, titanium nitrate, titanium sulfate, titanium phosphate, titanium perchlorate and titanium dioxide, among which titanium alkoxides are preferred. The titanium compound is used in an amount of from 0.001 to 10 parts by weight, preferably from 0.01 to 2 parts by weight, per one part by weight of the boron compound.

[0023]

Examples of the silicon compound are tetraalkyl- orthosilicates such as tetraethylorthosilicate, silica, etc.

As the boron compound, boric acid is given.

The boron compound and the silicon compound may be used in substantially equal amounts to each other.

[0024]

The titanosilicate for use in the reaction step may be silylated, using a silylating agent such as 1,1,1,3,3,3- hexamethyldisilazane or the like.

Preferably, the titanosilicate is -mixed with hydrogen peroxide before the reaction step.

[0025]

An amount of the titanosilicate for use in the

reaction step may be appropriately selected in accordance with a reaction mode: for example, in case of slurry complete mixing mode, 0.001 to 50 parts by. weight,

preferably 0.1 to 10 parts by weight of the titanosilicate is used per 100 parts by weight of a solvent in a reactor.

[0026]

Examples of the solvent for use in the reaction step include water, organic solvents and mixtures thereof.

Herein, the use of a mixed solvent of water and an organic solvent is preferred.

Examples of the organic solvent include alcohol

solvents, ketone solvents, nitrile solvents, ether solvents, aliphatic hydrocarbon solvents, aromatic hydrocarbon

solvents, halogenated hydrocarbon solvents, ester solvents and mixtures thereof.

Examples of the alcohol solvents include Ci-C₈

aliphatic alcohols such as methanol, ethanol, isopropanol and t-butanol; and C₂-C₈ glycols such as ethylene glycol and propylene glycol. As a preferable alcohol solvent, for example, C1-C4 monohydric alcohols may be exemplified, among which t-butanol is more preferable.

Examples of the aliphatic hydrocarbon solvents include

C5-C10 aliphatic hydrocarbon solvents such as hexane and heptane. Examples of the aromatic hydrocarbons include C6- C15 aromatic hydrocarbon solvents such as benzene,, toluene and xylene.

[0027] Examples of the nitrile solvents include C2-C4

alkylnitriles such as acetonitrile, propionitrile,

isobutyronitrile and butyronitrile, and benzonitrile , among which acetonitrile is preferable.

As the solvent for use in the reaction step, C1-C4 monohydric alcohols and acetonitrile are preferable in view of the catalytic activity and selectivity.

As the acetonitrile, there can be used, for example, crude acetonitrile which is formed as a by-product in the production step of acrylonitrile, and purified acetonitrile.

Examples of the impurities, that is, components other than acetonitrile, in the crude acetonitrile, are water, acetone, acrylonitrile, oxazole, allyl alcohol,

propionitrile, hydrocyanic acid, ammonia, copper and iron. Preferably, contents of copper and iron in the crude

acetonitrile are preferably as small as from 1% by weight or less. Purity of acetonitrile is, for example, 95% by weight or higher, preferably 99% by weight or higher, more preferably 99.9% by weight or higher.

[0028]

A weight ratio of water to the organic solvent in the mixed solvent is, for example, from 0 : 100 to 50 : 50, preferably from 10 : 90 to 40 : 60.

An amount of the solvent to be used is, for example, from 0.02 to 70 parts by weight, preferably from 0.2 to 20 parts by weight, more preferably from 1 to 10 parts by weight, per one part by weight of the olefin.

[0029]

As hydrogen peroxide for use in the reaction step, commercially available products may be used; or hydrogen peroxide may be prepared from oxygen and hydrogen in the presence of a noble metal catalyst, as described later (hereinafter optionally referred to as the hydrogen

peroxide-preparing step) . Hydrogen peroxide in the form of a solution in the above-described solvent such as water or acetonitrile may be supplied.

In the reaction step, a content of hydrogen peroxide per 100 parts by weight of the reaction solution is, for example, from 0.0001 to 90 parts by weight, preferably from 0.001 to 5 parts by weight. A ratio of the olefin to hydrogen peroxide, i.e., olefin : hydrogen peroxide, is from 1000 : Ί to 1 : 1000. (in molar ratio) .

[0030]

Herein, examples of the noble metal catalyst are catalysts containing noble metals such as palladium, platinum, ruthenium, rhodium, iridium, osmium and gold, or alloys or mixtures thereof. Preferable examples of the noble metal are palladium, platinum and gold; and a more preferable noble metal is palladium. As the palladium, for example, a palladium compound such as palladium colloid may be used (see, for example, JP-A-2002-294301, Example 1).

When a palladium compound is used as the noble metal

catalyst, a noble metal other than palladium, such as platinum, gold, rhodium, iridium or osmium may be contained. Examples of the preferable noble metal other than palladium are gold and platinum.

[0031]

Other examples of the palladium compound include tetravalent palladium compounds such as sodium

hexachloropalladate (IV) tetrahydrate and potassium

hexachloropalladate (IV) ; and divalent palladium compounds such as palladium (II) chloride, palladium (II) bromide, palladium (II) acetate, palladium (II) acetylacetonate , dichlorobis (benzonitrile) palladium (II),

dichlorobis (acetonitrile) palladium (II),

dichloro (bis (diphenylphosphino) ethane) palladium (II), dichlorobis (triphenylphosphine) palladium (II) ,

dichlorotetraamminepalladium (II),

dibromotetraamminepalladium (II), dichloro ( cycloocta-1 , 5- diene) alladium (II) and palladium (II) trifluoroacetate .

[0032]

The noble metal may be supported on a carrier for use. Example of the carrier include oxides such as silica, alumina, titania, zirconia and niobia; hydrates of niobic acid, zirconic acid, tungstic acid and titanic acid; carbon; and mixtures thereof. The carrier is preferably the above-described titanosilicate . When the noble metal is supported on a carrier other than the titanosilicate, the carrier supporting the noble metal is mixed with the titanosilicate, and this mixture can be used as the

catalyst.

The supporting of the noble metal compound is done by a known method such as impregnation.

[0033]

After the noble metal compound is supported on the carrier, it is preferable to reduce the resulting noble metal catalyst. As the reduction method with the use of a reducing gas, a suitable tube is charged with a carrier having a solid noble metal compound supported thereon and is then charged with a reducing gas for a reduction

treatment. Examples of the reducing gas include hydrogen, carbon monooxide, methane, ethane, propane, butane,

ethylene, propylene, butene, butadiene, and a mixed gas of two or more kinds selected therefrom. Among these,

hydrogen is preferable. The reducing gas may be diluted with a diluent gas such as nitrogen, helium, argon or steam, or a mixture of two or more kinds selected therefrom.

[0034]

A content of the noble metal in the noble metal

catalyst is, for example, from 0.01 to 20% by weight, preferably from 0.1 to 5% by weight. The lower limit of the noble metal to be used is, for example, 0.00001 part by weight, preferably 0.0001 part by weight or more, more preferably 0.001 part by weight, per one part by weight of the titanosilicate for use in the preparation step. The upper limit of the noble metal to be used is, for example, 100 parts by weight, preferably 20 parts by weight, more preferably 5 parts by weight, per one part by weight of the titanosilicate.

[0035]

The lower limit of a reaction temperature in the hydrogen peroxide-preparing step is, for example, 0°C, preferably 40°C. The upper limit of the reaction

temperature in the preparing step is, for example, 200°C, preferably 150°C.

The lower limit of a reaction pressure (or a gauge pressure) in the hydrogen peroxide-preparing step is, for example, 0.1 MPa, preferably 1 MPa, more preferably 20 MPa, still more preferably 10 MPa.

[0036]

In the hydrogen peroxide-preparing step, a partial pressure ratio of oxygen to hydrogen (oxygen : hydrogen) in the mixed gas which is to be supplied into a reactor is, for example, from 1 : 50 to 50 : 1, preferably from 1 : 10 to 10 : 1. When an oxygen partial pressure is higher than 1 : 50 in the ratio of oxygen : hydrogen, desirably, a rate of producing an oxirane compound tends to increase . When an oxygen partial pressure is lower than 50 : 1 in the ratio of oxygen : hydrogen, desirably, an amount of a by- product formed by reducing the carbon-carbon double bond of an olefin with a hydrogen atom is decreased, so that selectivity to an olefin oxide is improved.

[0037]

Preferably, the mixed gas of oxygen and hydrogen is handled in the presence of a diluent gas. Examples of the diluent gas include nitrogen, argon,- carbon dioxide, methane, ethane and propane, among which nitrogen and propane are preferable, and nitrogen is more preferable.

[0038]

The mixing ratio of oxygen, hydrogen, an olefin and a diluent gas is explained, when they are mixed for^" use, wherein propylene is used as the olefin, and a nitrogen gas is used as the diluent gas. Preferably, total 4.9 parts by volume or less of hydrogen and propylene, 9 parts by volume or less of oxygen, and the rest of a nitrogen gas are used per total 100 parts by volume of oxygen, hydrogen, olefin and a diluent gas; or total 50 parts by volume or more of hydrogen and propylene, 50 parts by volume or less of oxygen and the rest of a nitrogen. gas are used per total 100 parts by volume of oxygen, hydrogen, olefin and a diluent gas.

[0039]

An oxygen gas and an air containing oxygen may be used as the oxygen. Examples of the oxygen gas are an oxygen gas produced by an inexpensive pressure swing method, and a high purity oxygen gas produced by cryogenic separation.

An amount of the oxygen to be supplied is, for example, from 0.005 to 10 moles, preferably from 0.05 to 5 moles, per one mole of propylene to be supplied.

[0040]

As the hydrogen, for example, hydrogen obtained by steam-reforming hydrocarbon may be used. Purity of the hydrogen is, for example, 80% by volume or more, preferably 90% volume or more. An amount of the hydrogen to be supplied is, for example, from 0.05 to 10 moles, preferably from 0.05 to 5 moles, per one mole of propylene to be supplied.

[0041]

When a buffer is used in the reaction step, desirably, decrease in catalytic activity is prevented, or catalytic activity is more improved, so that utility of oxygen and hydrogen is improved. Here, the buffer refers to a salt capable of- imparting buffering action to a hydrogen ion concentration of the solution.

[0042] It is preferable to dissolve the buffer in the

reaction solution of the reaction step. Otherwise, in the hydrogen peroxide-preparing step, the buffer may be

"previously contained in a part of the noble metal catalyst. For example, an ammonium-containing noble metal such as Pd tetraamminechloride is supported on a carrier by an

impregnation method or the like, and the supported

ammonium-containing noble metal is then reduced to allow ammonium ions to remain therein, and the ammonium ions are generated as a buffer during the reaction step.

An amount of the buffer to be added is so selected as not to exceed a solubility of the buffer in a solvent for use in the reaction step. Preferably, it is, for example, from 0.001 mmol to 100 mmol per one kg of the solvent.

[0043]

An example of the buffer is a buffer containing 1) an anion selected from the following group and 2) a cation selected from the following group. That is, the anion 1) is selected from the group consisting of a sulfate ion, a hydrogen sulfate ion, a carbonate ion, a hydrogen carbonate ion, a phosphate ion, a hydrogen phosphate ion, a

dihydrogen phosphate ion, a hydrogen pyrophosphate ion, a pyrophosphate ion, a halogen ion, a nitrate ion, a

hydroxide ion and a Ci-Cio calboxylate ion; and the cation 2) is selected from the group consisting of ammonium, C1-C20 alkyl ammonium, C7-C20 alkyl aryl ammonium, an alkali metal and an alkaline earth metal.

Examples of the C1-C10 carboxylate ion include an acetate ion, a formate ion, a propionate ion, a butyrate ion, a valerate ion, a caproate ion, a caprylate ion, a caprate ion and a benzoate ion.

Examples of the alkyl ammonium include tetramethyl ammonium, tetraethyl ammonium, tetra-n-propyl ammonium, tetra-n-butyl ammonium and cetyl trimethyl ammonium.

Examples of the alkali metal cation and alkaline earth metal cation include a lithium cation, a sodium cation, a potassium cation, a rubidium cation, a cesium cation, a magnesium cation, a calcium cation, a strontium cation and a barium cation.

[0044]

Preferable examples of the buffer include salts of ammonium with inorganic acids, such as ammonium sulfate, ammonium hydrogen sulfate, ammonium carbonate, ammonium hydrogen carbonate, diammonium hydrogen phosphate, ammonium dihydrogen phosphate, ammonium phosphate, ammonium hydrogen pyrophosphate, ammonium pyrophosphate, ammonium chloride and ammonium nitrate; and salts of ammonium with C1-C10 carboxylic acids, such as ammonium acetate. Preferable ammonium salts are, for example, ammonium dihydrogen phosphate and diammonium hydrogen phosphate. [0045]

It. is preferable to add a quinoid compound in the reaction step, because selectivity to an olefin oxide is more improved.

As the quinoid compound, the compounds represented by the formula (1) are given:

(wherein each of R¹, R², R³. and R⁴ is independently a hydrogen atom; or R¹ and R², or R³ and R⁴ are linked to each other to form a benzene ring optionally having a

substituent or a naphthalene ring optionally having a substituent, together with a carbon atom to which each of R¹, R²,. R³ and R⁴ is bonded; and each of X and Y is

independently an oxygen atom or an NH group) .

[0046]

Examples of the compounds represented by the formula (1) include

1) a quinone compound (1A) of the formula (1) in which R¹, R², R³ and R⁴ are hydrogen atoms; and X and Y are oxygen atoms; 2) a quinonimine compound (IB) of the formula (1) in which R¹, R², R³ and R⁴ are hydrogen atoms; X is an oxygen atom; and Y is an NH group; and

3) a quinondiimine compound (1C) of the formula (1) in which R¹, R², R³ and R⁴ are hydrogen atoms; and X and Y are NH groups.

[0047]

Other examples of the compounds represented by the formula (1) include anthraquinone compounds represented by the formula (2 ) :

Y

(wherein X and Y are as defined in the formula (1) ; and each of R⁵, R⁶, R⁷ and R⁸ is independently a hydrogen atom, a hydroxyl group or an alkyl group (for example, C1-C5 alkyl groups such as a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group) .

[0048]

In the compound represented by the formula (1), each of X and Y is preferably an oxygen atom.

Examples of the compounds represented by the formula (1) include quinone compounds such as benzoquinone and naphthoquinone; anthraquinones including 2-alkyl

anthraquinone compounds such as 2-ethyl anthraquinone, 2-t- butyl anthraquinone, 2-amyl anthraquinone, 2-methyl

anthraquinone, 2-butyl anthraquinone, 2-t-amyl

anthraquinone, 2-isopropyl anthraquinone, 2-s-butyl

anthraquinone and 2-s-amyl anthraquinone, polyalkyl

anthraquinone compounds such as 1,3-diethyl anthraquinone, 2,3-dimethyl anthraquinone, 1, 4-dimethyl anthraquinone and 2,7-dimethyl anthraquinone, and polyhydroxyanthraquinone compounds such as 2 , 6-dihydroxyanthraquinone ; p-quinoid compounds such as naphthoquinone and 1, 4-phenanthraquinone; and o-quinoid compounds such as 1, 2-phenanthraquinone, 3,4- phenanthraquinone and 9 , 10-phenanthraquinone .

[0049]

Preferable examples of the compounds represented by the formula (1) include anthraquinones and 2-alkyl

anthraquinone compounds (the compounds of the formula (2) in which X and Y are oxygen atoms; R⁵ is an alkyl group; R⁶ is a hydrogen atom; and R⁷ and R⁸ are hydrogen atoms) .

[0050]

An amount of the quinoid compound for use in the reaction step is, for example, from 0.001 to 500 mmol, preferably from 0.01 to 50 mmol, per one kg of the solvent.

[0051] In the reaction step, a salt comprising ammonium, alkyl ammonium or alkyl aryl ammonium may be added during the^' reaction step.

[0052]

The quinoid compound may be prepared by oxidizing a dihydro-form of the quinoid compound with oxygen or the like in the reaction step. For example, hydroquinone or a hydrogenated quinoid compound, such as 9 , 10-anthracene diol, is added to a liquid phase and is then oxidized with oxygen in a reactor to produce a quinoid compound for use..

Examples of the dihydro-form of the quinoid compound include compounds represented by the formula (3) which are dihydro-forms of the compounds represented by the formula

(1) :

(wherein R¹, R², R³, R⁴, X and Y are as defined above); and [0053]

compounds represented by the formula (4) which are dihydro- forms of the compounds represented by the formula (2) :

(wherein X, Y, R⁵, R⁶, R⁷ and R⁸ are as defined above) .

In the formula (3) and the formula (4) , X and Y are preferably oxygen atoms.

Preferable examples of the dihydro-forms of the quinoid compounds are dihydro-forms corresponding to the above-described preferable quinoid compounds.

[0054]

The reaction step may be continuously carried out. For example, there is given a step of continuously

supplying hydrogen peroxide and an olefin into a reactor which holds a solvent and a titanium silicate catalyst, and optionally a buffer, a quinoid compound, etc.; reacting them in the reactor; and continuously supplying the _ obtained reaction solution to a decomposition tank

described later.

When hydrogen peroxide is produced from oxygen and . hydrogen as described above, a noble metal catalyst is further charged in the reactor. Oxygen and hydrogen are continuously supplied into the reactor to continuously produce hydrogen peroxide in the reactor, and simultaneously, a reaction solution containing hydrogen peroxide and an olefin oxide is continuously obtained.

Oxygen, hydrogen and the olefin may be continuously

supplied as a mixed gas which optionally may contain a diluent gas.

It is preferable to equip the reactor with a mixing means such as a mixing blade. The reactor equipped with the mixing means is likely to efficiently mix hydrogen peroxide and titanium silicate.

[0055]

A plurality of reactors may be used in the reaction step.. Such a plurality of reactors are concretely shown in Fig. 1 as reactors (1) to (3) (hereinafter optionally referred to as the reactor (1), the reactor (2) and the reactor (3) , respectively) . The reactor (1) is provided at its inside with a paddle blade. A^' -'tube (5) for

continuously supplying a mixed gas containing oxygen, hydrogen and an olefin is connected to the reactor (1) , and a tube (6) for continuously supplying a reaction solution from the reactor (1) to the reactor (2) is connected to the reactor (1). The reaction step is carried out in the reactor (1) , and the resulting reaction solution is continuously supplied to the reactor (2) through the tube (6) connected to the reactor (2) . The reactor (2) is provided at its inside with a paddle blade. The tube (5) for continuously supplying the mixed gas containing oxygen, hydrogen and an olefin is connected to the reactor (2), and a tube (7) for

continuously supplying the reaction solution from the reactor (2) to the reactor (3) is connected to the reactor (2). The reaction step is carried out in the reactor (2),^' and the resulting reaction solution is continuously

supplied to the reactor (3) through the tube (7) connected to the reactor (3) .

Preferably, the reaction product obtained in the reaction step (i.e., the reaction solution supplied from the reactor to a decomposition tank) is supplied to the decomposition tank after the removal of the titanosilicate and the noble metal catalyst. Specifically, only the supernatant of the reaction solution, containing almost no catalyst component described above, in the reactor is supplied; or a filter or the like is provided on the tube for continuously supplying the reaction solution from the reactor to the ^' decomposition tank, or before or behind the same tube, so as to separate the above-described catalyst components.

In case where a plurality of reactors are used,, before the supply of the reaction solution from one reactor to another reactor, the titanosilicate catalyst and the noble metal catalyst are removed from the reaction solution in the same manner as above, and the resulting solution is supplied to another reactor.

[0056]

Next, the contact step will be described.

The present substance for use in the contact step contains at least one kind of element selected from the group consisting of manganese and platinum group elements. Examples of the platinum group elements include ruthenium, rhodium, palladium, osmium, iridium and platinum, among which rhodium, palladium, iridium and platinum are

preferable, and palladium and platinum are more preferable.

[0057]

The present substance may be a compound or a simple substance.

In case where the present substance is a simple substance, the simple substance is, for example, a

manganese simple substance, a ruthenium simple substance, a rhodium simple substance, a palladium simple substance, an osmium simple substance, an iridium simple substance or a platinum simple substance. The simple substance is

preferably a rhodium simple substance, a palladium simple substance, an iridium simple substance or a platinum simple substance, more preferably a palladium simple substance or a platinum simple substance. In this connection, the present substance may be a ruthenium simple substance, a rhodium simple substance, a palladium simple substance, an osmium simple substance, an iridium simple substance or a platinum simple substance which contains a simple substance selected from the

elements of Group 11 of the periodic table (e.g., cold, silver, copper or the like) in such an amount that the effect of the present invention is not impaired.

[0058]

In case where the present substance is a compound, the compound is, for example, an alloy of the above-exemplified metals, or an oxide containing an element selected from the above-exemplified elements. Preferable examples of the compound include manganese oxide, manganese dioxide,^' and oxides such as Ru0₄, Ru0₂, Rh₂0₃, PdO, Os0₂, Os0₄, Ir0₂, etc., among which manganese dioxide is more preferable. Herein, the manganese dioxide means a nonstoichiometric compound with a component ratio of MnO_x (x = about 1.9 to about 2) .

[0059]

The present substance may be supported on a carrier. When the present substance is a simple substance,

preferably, the simple substance is supported on a carrier.

Examples of the carrier include oxides of elements inert to an oxiranyl group (e.g., silica, alumina, titania, zirconia, niobia, zeolite, etc.), hydrates of elements' inert to an oxiranyl group (e.g., niobic acid, zirconic acid, tungstic acid, titanic acid, etc.) and carbons (e.g., activated carbon, carbon black, graphite, carbon nanotube, etc.), among which activated carbon is preferable.

A content of the present substance per 100 parts by weight of the present substance supported on the carrier is, for example, from 0.0001 to 20 parts by weight, preferably from 0.001 to 10 parts by weight.

[0060]

An amount of the present substance to be used in the contact step is, for example, from 0.01 to 1,000 parts by weight, preferably from 0.1 to 100 parts by weight, per one part by weight of hydrogen peroxide contained in the

present solution.

[0061]

A reaction product to be used in the contact step is the reaction product obtained in the above-described

reaction step (hereinafter optionally referred to as the present reaction product). The present reaction product contains residual hydrogen peroxide, an olefin oxide and a solvent.

The olefin oxide herein referred to is an oxirane compound obtained by substituting the carbon-carbon double bond of the above-described olefin with the oxiranyl group. Examples of the oxirane compound include C₂-Cio oxirane compounds such as ethylene oxide (oxirane) , propylene oxide (1-methyloxirane) , 1-ethyloxirane, 1-propyloxirane, 1- butyloxirane , 1-pentyloxirane, 1-hexyloxirane , 1- heptyloxirane, 1-octyloxirane, l-methyl-2-ethyloxirane and l-methyl-2-methyloxirane . A preferable example of the oxirane compound is, for example, propylene oxide or the like.

[0062]

A content of the olefin oxide in the present reaction product is, for example, from 0.1 to 50 parts by weight, preferably from 1 to 30 parts by weight, per 100 parts by weight of the present solution.

[0063]

The solvent to be contained in the present reaction product may be the same one as the solvent used in the above-described reaction step. Preferably, the solvent used in the reaction step is used, as it is.

An amount of the solvent to be used is, for example, from 1 to 1,000,000 parts by weight, preferably from 10 to 100,000 parts by weight, more preferably from 100 to 10,000 parts by weight, per one part by weight of the present substance.

[0064]

A content of hydrogen peroxide in the present reaction product is, for example, from 0.001 to 10 parts by weight, preferably from 0.005 to 5 parts by weight, per 100 parts by weight of the present reaction product.

[0065] ·

Next, conditions for the reaction in the contact step will be described.

The lower limit of a reaction temperature in the contact step is, for example, 0°C, preferably 20°C. The upper limit of the reaction temperature in the contact step is, for example, 200°C, preferably 150°C.

A pressure (or a gauge pressure) in the contact step may be equal to the pressure in the reaction step, or may be reduced' after the reaction step. The contact step may be carried out under a normal pressure or a reduced

pressure. Preferably, the contact step is- carried out under a pressure the same as that in the reaction step.

[0066]

The contact step may be continuously carried out.

Specifically, the present reaction product obtained in the reaction step is continuously supplied into a decomposition tank which holds the solvent and the present substance, so that the present reaction product is mixed with the solvent and the present substance in the decomposition tank so as to decompose the residual hydrogen peroxide.

A residence time of the reaction solution in the decomposition tank is at least 0.01 hour, preferably from 0.1 to 5 hours, in order to decompose the hydrogen peroxide in the present reaction product.

[0067]

A specific embodiment of the decomposition tank is shown in Fig. 1, for example, as the decomposition tank (4) (hereinafter optionally referred to as the decomposition tank (4)). The decomposition tank (4) is equipped at its inside with a paddling blade, and a tube (8) for

continuously receiving the reaction solution from the reactor (3) is connected to the decomposition tank (4).

Thus, hydrogen peroxide is decomposed in the decomposition tank (4), and a solution which contains an olefin oxide having a less content of hydrogen peroxide is obtained therein. A tube (9) for continuously discharging this solution is connected to the decomposition tank (4) so as to provide this solution which contains the olefin oxide having a less content of hydrogen_. peroxide . Within the decomposition tank, the residual hydrogen peroxide is decomposed, but the olefin oxide is hardly decomposed.

Preferably, the present substance is left to remain in the decomposition tank, when there is obtained the solution which contains the olefin oxide of which the residual hydrogen peroxide is decomposed. Specifically, only the supernatant of the reaction solution which hardly contains the present substance in the decomposition tank is supplied; or the above-described catalytic component is separated through the tube (9) for use in continuously obtaining the solution containing the olefin oxide from the decomposition tank, or through a filter provided before or behind the tube (9).

[0068]

As the reactor for use in the reaction step and the decomposition tank for use in the contact step, there may be used, for example, a fixed-bed flow reaction apparatus, a slurry-complete mixing flow reaction apparatus, etc.

When a slurry-complete mixing flow reaction apparatus is used, a titanosilicate and a noble metal catalyst or the present substance (which are optionally collectively referred to as a catalyst) are allowed to pass through a filter provided inside or outside a reactor and are again supplied into the reactor. This is described in detail: for example, a part of the catalyst in the reactor or a decomposition tank is continuously or intermittently drawn out therefrom and is then optionally regenerated and is then supplied into the reactor or the decomposition tank; otherwise, for example, a part of the . catalyst in a reactor or a decomposition tank is continuously or intermittently discharged therefrom, and the reaction apparatus is

supplemented with a new titanosilicate and a new noble metal catalyst or the present substance in amounts equivalent to the amount of the discharged catalyst.

When a fixed-bed flow reaction apparatus is used, for example, a reactor which holds a catalyst degraded in production activity for an olefin oxide is used to .

regenerate the catalyst, and thus, the reactor is used to carry out the reaction and the regeneration alternately and repeatedly; and also, a decomposition tank which holds the present substance degraded in activity is used to carry out the decomposition of hydrogen peroxide and the regeneration of the present substance alternately and repeatedly in the same manner. In such a case, it is preferable to use the catalyst molded with a profiling material or the like.

[0069]

The product obtained in the contact step is separated by distillation or the like to obtain an_. olefin oxide. For example, when a propylene oxide is obtained, the product obtained in the contact step is allowed to pass through a gas-liquid separation column, a solvent-separation column, a crude propylene oxide separation column, a propane

separation column and a solvent purification column, so as to be separated into crude propylene oxide, a gaseous component mainly comprised of hydrogen, oxygen and nitrogen, a recovered propylene, a recovered solvent and a recovered quinone compound. Desirably, the recovered propylene, recovered solvent and recovered quinone compound are again supplied into the reactor so as to be recycled. The recovered propylene, if contains impurity such as propane, cyclopropane, methylacetylene, propadiene, butadiene, butane, butene, ethylene, ethane, methane or hydrogen, may be optionally purified by separation so as to be recycled.

[0070]

A solution containing an olefin oxide, hydrogen peroxide and a solvent, other than the present reaction product, such as a mixture of a separately prepared olefin oxide, hydrogen peroxide and solvent, may be brought into contact with the present substance to thereby remove the hydrogen peroxide.

[0071]

According to the present invention, it becomes possible to decompose hydrogen peroxide, without any substantial production of impurities such as glycol, etc. from a solution containing an olefin oxide which retains hydrogen peroxide (for example, without any substantial production of propylene glycol from a solution containing propylene oxide which retains hydrogen peroxide) .

[0072]

Examples

Hereinafter, the present invention is described in more detail by way of Examples thereof.

[0073] (Preparation Example 1 of Titanosilicate )

An autoclave was charged with 899 g of piperidine, 2,402 g of pure water, 112 g of TBOT ( tetra-n-butyl

orthotitanate) , 565 g of boric acid and 410 g of fumed silica (cab-o-sil M7D) at a room temperature (about 25°C) under an air atmosphere, and these materials were dissolved under stirring to form a gel, which was then aged for 1.5 hours. After that, the autoclave was sealed up.

Subsequently, the temperature in the autoclave was raised over 8 hours while the gel in the autoclave was stirred.

The gel was maintained at 160°C for 120 hours to obtain a suspended solution. The. suspended solution was filtered, and the separated cake was washed with water until the pH of the filtrate reached about 10. The obtained cake was dried at 50°C to obtain white powder which still contained water. To 15 g of the powder was added 750 mL of 2 N nitric acid, and the mixture was heated for 20 hours under reflux. Then, the resulting product was filtered, washed with water until the pH of the filtrate indicated almost a neutralization value, and was then thoroughly dried at 50°C to obtain 11 g of white powder. An X-ray diffraction pattern of the white powder was measured by using an X-ray diffraction apparatus using copper K-a radiation. As a result, it was confirmed that the white powder was a Ti-MWW precursor. The powder was subjected to IPC emission spectrometry and was confirmed to have a titanium content of 1.65% by weight.

Next, 2.28 g of the powder was stirred in about 80 ml of. a solution of water/acetonitrile (= 20/80 in weight ratio) containing 0.1% by weight of hydrogen peroxide at a room temperature for one hour, and the mixture was filtered to obtain a titanosilicate .

[0074]

(Production Example 1 of Present Reaction Product

Obtainable in Reaction Step)

A reaction step for obtaining propylene oxide from separately prepared hydrogen peroxide and propylene in the presence of the titanosilicate and a solvent in the reactor (1) is described below.

An autoclave equipped with a jacket and having an internal volume of 300 cc was charged with 131 g of an aqueous acetonitrile of water/acetonitrile (= 30/70 in weight ratio) and 2.28 g of the above-obtained

titanosilicate; and then, a pressure in the autoclave was adjusted to an absolute pressure of 4 MPa with nitrogen; and an inner temperature of the autoclave was adjusted to 50°C by circulating hot water through the jacket. To the autoclave were continuously supplied 143 L (standard condition) /Hr of a nitrogen gas, 236 g/Hr of an aqueous acetonitrile of water/acetonitrile (= 30/70 in weight ratio) containing 0.7 mmol/kg of anthraquinone , 0.7 mmol/kg of ammonium dihydrogen phosphate and 3.3% by weight of hydrogen peroxide, and 36 g/Hr of liquid propylene. During the reaction step, the reaction temperature was controlled at 50°C, and the reaction pressure was controlled at 4 MPa.. The titanosilicate as the solid component Was filtered through a sintered filter. Then, the pressure was returned to an ordinary pressure. After that, the filtered solid was subjected to gas-liquid separation so as to

continuously draw out the liquid component and the gas component. After 6.5 hours, the liquid component and the gas component were sampled at the same time, and each sample was analyzed by gas chromatography to measure contents of propylene oxide (PO) and propylene glycol (PG) . A concentration of hydrogen peroxide was measured by titration using potassium permanganate. Increase of PO including PO accompanying the liquid component and the gas was 177 mmol/hr. The liquid component contained 4.2% by weight of PO, 0.2% by weight of PG and 4,530 ppm by weight of hydrogen peroxide.

[0075]

(Production Example 2 of Present Reaction Product

Obtainable in Reaction Step)

A reaction step for obtaining propylene oxide from hydrogen peroxide and propylene, while preparing the hydrogen peroxide from oxygen and hydrogen, in the presence of the titanosilicate and a solvent in the reactor (1) is described below.

An autoclave equipped with a jacket and having an internal volume of 300 cc was charged with 131 g of an aqueous acetonitrile of water/acetonitrile (= 30/70 in weight ratio), 2.28 g of the above-obtained titanosilicate and 0.20 g of an activated carbon catalyst having 1% by weight of palladium supported thereon; and then, a pressure in the autoclave was adjusted to an absolute pressure of 4 MPa with nitrogen; and an inner temperature of the

autoclave was adjusted to 50°C by circulating hot water through the jacket. To the autoclave were continuously supplied 146 L (standard condition) /Hr of a mixed gas comprising 3.6% by volume of hydrogen, 2.1 by volume of oxygen and 94.3 by volume of nitrogen, 90 g/Hr of an

aqueous acetonitrile of water/acetonitrile (= 30/70 in weight ratio) containing 0.7 mmol/kg of anthraquinone and 3.0 mmol/kg of diammonium hydrogen phosphate, and 36 g/Hr of liquid propylene. During the reaction, the reaction temperature was controlled at 50°C, and the reaction

pressure was controlled at 4 MPa. The titanosilicate and the palladium-supported activated carbon catalyst as the solid components were filtered through a sintered filter, and then, the pressure was returned to an ordinary pressure. After that, gas-liquid separation was performed, and the liquid component and the gas component were continuously drawn out. After 6 hours, the liquid component and the gas component were sampled at the same time, and each sample was analyzed by gas chromatography to measure contents of propylene oxide (PO) and propylene glycol (PG) . A

concentration of hydrogen peroxide was measured by

titration using potassium permanganate. Increase of PO including PO accompanying the liquid component and the gas was 50 mmol/hr. The liquid component contained 3.1% by weight of PO, 0.2% by weight of PG and 760 ppm by weight of hydrogen peroxide .

[0076]

(Production Example 3 of Present Reaction Product

Obtainable in Reaction Step)

A reaction step for obtaining propylene oxide from hydrogen peroxide and propylene contained in an aqueous acetonitrile, while preparing the hydrogen peroxide from oxygen and hydrogen in the presence of the titanosilicate and a solvent in the reactor (2) or (3) is described below.

An autoclave equipped with a jacket and having an internal volume of 300 cc was charged with 131 g of an aqueous acetonitrile of water/acetonitrile (= 30/70 in weight ratio), 2.28 g of the above-obtained titanosilicate and 0.198 g of an activated carbon catalyst having 1% by weight of palladium supported thereon; and then, a pressure in the autoclave was adjusted to an absolute pressure of 4 MPa with nitrogen; and an inner temperature of the

aqueous acetonitrile of water/acetonitrile (= 30/70 in weight ratio) containing 0.7 mmol/kg of anthraquinone, 0.7 mmol/kg of ammonium dihydrogen phosphate and 10.0% by weight of propylene peroxide, and 36 g/Hr of liquid

propylene. During the reaction, the reaction temperature was controlled at 50°C, and the reaction pressure was controlled at 4 MPa. The titanosilicate and the palladium- supported activated carbon catalyst as the solid components were filtered through a sintered filter and were then subjected to gas-liquid separation. Then, the pressure was returned to an ordinary pressure. After that, the liquid component and the gas component were continuously drawn out. After 6 hours had passed, the liquid component and the gas component were sampled at the same time, and each sample was analyzed by gas chromatography to measure contents of propylene oxide (PO) and propylene glycol (PG) . A

concentration of hydrogen peroxide was measured by titration using potassium permanganate. Increase of PO including PO accompanying the liquid component and the gas was 3,6 mmol/hr. The liquid component contained 11.6% by weight of PO, 0.3% by weight of PG and 980 ppm by weight of hydrogen peroxide.

[0077]

Example 1

Preparation of Solution Containing Olefin Oxide, Hydrogen Peroxide and Solvent

Two hundreds gram of Solution 1 (acetonitrile/water =

7/3) was prepared by mixing 10.8% by weight of propylene oxide, 0.002% by weight of propylene glycol, 1.1% by weight of hydrogen peroxide, 0.7 mmol/kg of anthraquinone as a quinone compound (based on the aqueous acetonitrile

solution) and 3 mmol/kg of ammonium dihydrogen phosphate

((NH₄)₂HP0₄) as a buffer (based on the aqueous acetonitrile solution) .

[0078]

Contact Step

Eight hundreds mL/min. of a nitrogen gas was allowed to pass through a decomposition tank filled with Solution 1, and then, 2.0 g of manganese dioxide was added thereto, and the mixture was stirred at 50°C.

Zero minute was set just after the addition of

manganese dioxide. Contents of hydrogen peroxide (H₂0₂) and propylene, oxide (PO) in the decomposition tank were measured at each stirring time indicated in Table 1.

Retentions of H₂0₂ and PO calculated on assumption that the contents thereof found just after the addition of manganese dioxide were 100, respectively, were indicated in Table 1. In Table, the notation "-" means that it was not measured.

Table 1 also shows the results of a solution obtained by stirring the same mixture which however contained no manganese dioxide.

As can be understood from Table 1, the retention of H₂0₂ was decreased to 0.1% in 40 minutes. The content of PO was decreased by the evaporated amount thereof due to the flow of a nitrogen gas, but was retained at the same level as that found in the solution containing no manganese dioxide.

A concentration of propylene glycol (PG) in Solution 1 was also shown in Table 1. It is found that the

concentration of PG was hardly increased when manganese dioxide was added.

[0079] Table 1

[0080]

Example 2

Preparation of Solution Containing Olefin Oxide, Hydrogen Peroxide and Solvent

Two hundreds gram of Solution 2 (acetonitrile/water = 7/3) was prepared by mixing 10.1% by weight of propylene oxide, 0.003% by weight of propylene glycol, 1.2% by weight of hydrogen peroxide, 0.7 mmol/kg of anthraquinone as a quinone compound (based on the aqueous acetonitrile

solution) and 3 mmol/kg of diammonium hydrogen phosphate

((NH )₂HP0₄) as a buffer (based on the aqueous acetonitrile solution) .

[0081]

Contact Step

Eight hundreds mL/min. of a nitrogen gas was allowed to pass through a decomposition tank filled with Solution 2, and then, 0.1 g of activated carbon having 5% by weight of ruthenium simple substance supported thereon (hereinafter optionally referred to as Ru-supported activated carbon) was added thereto, and the mixture was stirred at 50°C.

Zero minute was set just after the addition of the Ru- supported activated carbon. Contents of hydrogen peroxide (H₂0₂) and propylene oxide (PO) in the decomposition tank were measured at each stirring time indicated in Table 2. Retentions of H2O2 and PO calculated on assumption that the contents thereof found just after the addition of the Ru- supported activated carbon were 100, respectively, were indicated in Table 2. In Table, the notation "-" means that it was not measured.

Table 2 also shows the results of a solution obtained by stirring the same mixture which however contained no Ru- supported activated carbon.

As can be understood from Table 2, the retention of

H₂0₂ was decreased to 2.5% in 120 minutes. The content of PO was decreased by the evaporated amount thereof due to the flow of the nitrogen gas, but was retained at the same level as that found in the solution containing no Ru- supported activated carbon.

A concentration of propylene glycol (PG) in Solution 2 was also shown in Table 2. It is found that the

concentration of PG was hardly increased when the Ru- supported activated carbon was added.

[0082] Table 2

[0083]

Example 3

Preparation of Solution Containing Olefin Oxide, Hydrogen Peroxide and Solvent

Two hundreds gram of Solution 3 (acetonitrile/water = 7/3) was prepared by mixing 10.3% by weight of propylene oxide, 0.005% by weight of propylene glycol, 1.2% by weight of hydrogen peroxide, 0.7 mmol/kg of anthraquinone as a quinone compound (based on the aqueous acetonitrile

solution) and 3 mmol/kg of diammonium hydrogen phosphate

((NH₄)₂HP0₄) as a buffer (based on the aqueous acetonitrile solution) . -

[0084]

Contact Step

Eight hundreds mL/min. of a nitrogen gas was allowed to pass through a decomposition tank filled with Solution 3, and then, 0.2 g of activated carbon having 5% by weight of palladium simple substance supported thereon (hereinafter optionally referred to as Pd-supported activated carbon) was added thereto, and the mixture was stirred at 50°C.

Zero minute was set just after the addition of the Pd- supported activated carbon. Contents of hydrogen peroxide (H₂0₂) and propylene oxide (PO) in the decomposition tank were measured at each stirring time indicated in Table 3. Retentions of Η₂0₂ and PO calculated on assumption that the contents thereof found just after the addition of the Pd- supported activated carbon were 100,. respectively, were indicated in Table 3. In Table, the notation "-" means that it was not measured.

Table 3 also shows the results of a solution obtained by stirring the same mixture which however contained no Pd- supported activated carbon.

As can be understood from Table 3, the retention of

H₂0₂ was decreased to 0.01% in 20 minutes. The content of PO was decreased by the evaporated amount thereof due to the flow of the nitrogen gas, but was retained at the same level as that found in the solution containing no Pd- supported activated carbon.

A concentration of propylene glycol (PG) in Solution 3 was also shown in Table 3. It is found that the

concentration of PG was hardly increased when the Pd- supported activated carbon was added.

[0085] Table 3

[0086]

Example 4

Preparation of Solution Containing Olefin Oxide, Hydrogen Peroxide and Solvent

Two hundreds gram of Solution 4 (acetonitrile/water = 7/3) was prepared by mixing 10.0% by weight of propylene oxide, 0.004% by weight of propylene glycol, 1.2% by weight of hydrogen peroxide, 0.7 mmol/kg of anthraquinone as a quinone compound (based on the aqueous acetonitrlle

solution) and 3 mmol/kg of diammonium hydrogen phosphate ■ ( (NH₄) 2HPO4) as a buffer (based on the aqueous acetonitrile solution) . .

[0087]

Contact Step'

Eight hundreds mL/min. of a nitrogen gas was allowed to pass through a decomposition tank filled with Solution 4, and then, 0.2 g of activated carbon having 5% by weight of platinum simple substance supported thereon (hereinafter optionally referred to as Pt-supported activated carbon) was added thereto, and the mixture was stirred at 50°C.

Zero minute was set just after the addition of the Pt- supported activated carbon. Contents of hydrogen peroxide (H2O2) and propylene oxide (PO) in the decomposition tank were measured at each stirring time indicated in Table 4. Retentions of H₂0₂ and PO calculated on assumption that the contents thereof found just after the addition of the Pt- supported activated carbon were 100, respectively, were indicated in Table 4. In Table, the notation "-" means that it was not measured.

Table 4 also shows the results of a solution obtained by stirring the same mixture which however contained no. Pt- supported activated carbon.

As can be understood from Table 4,. the retention of

H₂0₂ was decreased to 0.3% in 30 minutes. The content of PO was decreased by the evaporated amount thereof due to the flow of the nitrogen gas, but was retained at. the same level as that found in the solution containing no Pt- supported activated carbon.

A concentration of propylene glycol (PG) in Solution 4 was also shown in Table 4. It is found that the

concentration of PG was hardly increased when the Pt- supported activated carbon was added.

[0088] Table 4

[0089]

Example 5

As the present solution, the liquid component obtained in Production Example 1 for the present reaction product obtainable in the reaction step was used, and the liquid component was subjected to the contact, step in the same manner as in Example 1.

[0090]

Example 6

As the present solution, the liquid component obtained in Production Example 2 for the present reaction product obtainable in the reaction step was used, and the liquid component was subjected to the contact step in the same manner as in Example 3.

[0091]

Example 7

As the present solution, the liquid component obtained in Production Example 3 for the present _. reaction product obtainable in the reaction step was used, and the liquid component was subjected to the contact step in the same manner as in Example 4.

[0092]

Industrial Applicability

According to the present invention, an olefin oxide having a less content of hydrogen peroxide can be obtained from a solution containing an olefin oxide and hydrogen peroxide.

[0093]

Description of Reference Numerals

(1) to (3) : reactors

(4) : a decomposition tank

(5) : a tube for supplying a mixed gas of hydrogen peroxide, oxygen, hydrogen, olefin and

diluent gas

(6) to (8): tubes for discharging reaction solutions

(containing non-reacted hydrogen peroxide and olefin oxide) and tubes for supplying the reaction solutions

(9) : a tube for discharging a reaction solution

(containing olefin oxide having a less content of non-reacted hydrogen peroxide)

Claims

1. A method for producing an olefin oxide, comprising the steps of

[2] bringing the reaction product obtained in the previous step, into contact with a substance containing at least one element selected from the group consisting of manganese and platinum group elements.

2. The method according to Claim 1, wherein said solvent is a mixed solvent of an organic solvent and water.

3. The method according to Claim 2, wherein said organic solvent is acetonitrile .

4. The method according to any one of Claims 1 to 3, wherein said titanosilicate is a layer titanosilicate which has ring-structural pores each containing 12 or more oxygen atoms.

5. The method according to any one of Claims 1 to 4, wherein said titanosilicate is a Ti-MWW precursor.

6. The method according to any one of Claims 1 to 5, wherein said substance is a compound containing manganese or a platinum group element, or a simple substance

containing a platinum group element.

7. The method according to any one of Claims 1 to 5, wherein said substance is manganese dioxide.

8. The method according to any one of Claims 1 to 5, wherein said substance is a substance containing at least one kind of element selected from the group consisting of rhodium, palladium, iridium and platinum.

9. The method according to any one of Claims 1 to 5, wherein said substance is a substance containing palladium or platinum.

10. The method according to any one of Claims 1 to 9, wherein said substance is supported on a. carrier.

11. The method according to Claim 10, wherein said carrier is activated carbon.

12. A method for removing hydrogen peroxide, comprising a step of bringing a substance containing at least one kind of element selected from the group consisting of manganese and platinum group elements, into contact with a solution containing an olefin oxide, hydrogen peroxide and a solvent.