WO2012015056A1 - Titanosilicate and process for producing olefin oxide using the titanosilicate as catalyst - Google Patents

Abstract

The present invention relates to a titanosilicate having a bulk density of 0.05 g/ml to 0.15 g/ml, and having an X-ray diffraction pattern with the following values: lattice spacing d/Angstrom 12.4 +/- 0.8, 10.8 +/- 0.5, 9.0 +/- 0.3, 6.0 +/- 0.3, 3.9 +/- 0.1, 3.4 +/- 0.1. The present invention also relates to a process for producing the titanosilicate and a process for producing an olefin oxide using the titanosilicate as a catalyst.

Description

DESCRIPTION

TITANOSILICATE AND PROCESS FOR PRODUCING OLEFIN OXIDE USING THE TITANOSILICATE AS CATALYST

TECHNICAL FIELD

[0001]

The present application is filed, claiming the priorities based on the Japanese Patent Application No . 2010-171783 (filed on July 30, 2010) , and a whole of the contents of the application is incorporated herein by reference.

The present invention relates to a titanosilicate, a process for producing thereof and a process for producing an olefin oxide using the titanosilicate as a catalyst.

BACKGROUND ART

[0002]

In a production process of an olefin oxide such as propylene oxide, a titanosilicate is used as a catalyst. As such a catalyst, for example, JP 2005-262164 A describes a titanosilicate obtained by hydrothermally synthesizing of a boron-containing compound, tetrabutyl orthotitanate, fumed silica and piperidine at a temperature of 170°C, and bringing the obtained layered compound (also referred to as an as-synthesized sample) into contact with an aqueous nitric acid solution under reflux conditions. JP 2005-262164 A also describes a process for producing a propylene oxide from hydrogen peroxide and propylene by using the titanosilicate as a catalyst.

SUMMARY OF INVENTION

PROBLEM TO BE SOLVED BY THE INVENTION

[0003]

According to a conventional production process of propylene oxide using a titanosilicate as a catalyst, a yield of an olefin compound based on the amount of an oxidizing agent (hereinafter sometimes simply referred to as a "yield"), such as a yield of propylene oxide based on the amount of hydrogen peroxide, is not necessarily satisfactory.

[0004]

An object of the present invention is to provide a catalyst capable of producing an olefin oxide from an oxidizing agent and an olefin compound in a high yield. MEANS FOR SOLVING THE PROBLEM

[0005]

As a result of the present inventors' earnest studies for solving the problems, they have found that a titanosilicate with low bulk density is a catalyst capable of producing an olefin oxide in a high yield, and accomplished the present invention.

[0006]

The present invention provides the followings:

[1] A titanosilicate having a bulk density of 0.05 g/ml to 0.15 g/ml, and having an X-ray diffraction pattern with the following values :

lattice spacing d/A

12.4 ± 0.8

10.8 ± 0.5

9.0 ± 0.3

6.0 ± 0.3

3.9 ± 0.1

3.4 ± 0.1.

[2] The titanosilicate according to the above item [1] , wherein the bulk density is 0.08 g/ml to 0.11 g/ml.

[3] A process for producing a titanosilicate, comprising a first step of heating a mixture containing a structure-directing agent, a compound containing an element belonging to Group 13 of the periodic table, a titanium-containing compound, a silicon-containing compound and water under a temperature condition of lower than 155°C to obtain a solid; and a second step of bringing at least one selected from the group consisting of inorganic acids and titanium-containing compounds into contact with the solid obtained in the first step. [4] The process for producing a titanosilicate according to the above item [3], wherein the compound containing an element belonging to Group 13 of the periodic table is a

boron-containing compound.

[5] The process for producing a titanosilicate according to the above item [3] or [4], wherein the structure-directing agent is piperidine or hexamethyleneimine .

[6] The process for producing a titanosilicate according to any one of the above items [3] to [5] , further comprising a third step in which the titanosilicate obtained in the second step is heated at a temperature in the range of 250°C to 1000°C.

[7] The process for producing a titanosilicate according to any one of the above items [3] to [6], further comprising a fourth step in which the titanosilicate obtained in the second step or the third step is brought into contact with the

structure-directing agent.

[8] The process for producing a titanosilicate according to any one of the above items [3] to [7], further comprising a fifth step in which the titanosilicate obtained in the second step, the third step or the fourth step is silylated with a silylating agent .

[9] The process for producing a titanosilicate according to any one of the above items [3] to [8], further comprising a sixth step in which the titanosilicate obtained in the second step, the third step, the fourth step or the fifth step is brought into contact with hydrogen peroxide.

[10] A titanosilicate obtained by the process according to any one of the above items [3] to [9] .

[11] A catalyst for producing an olefin oxide comprising the titanosilicate according to the above item [1], [2] or [10].

[12] A process for producing an olefin oxide, comprising a step of oxidizing an olefin compound with an oxidizing agent in the presence of the catalyst according to the above item [11] .

[13] The process for producing an olefin oxide according to the above item 12, wherein the olefin compound is propylene, and wherein the oxidizing agent is hydrogen peroxide.

[0007]

According to the present invention, a novel

titanosilicate can be provided as a catalyst for an olefin oxide capable of giving a higher yield based on the amount of an oxidizing agent.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008]

Fig. 1 is an electron micrograph showing the

titanosilicate obtained in Example 1.

Fig. 2 is an electron micrograph showing the

titanosilicate obtained in Reference Example 1. MODES FOR CARRYING OUT THE INVENTION [0009]

The titanosilicate of the present invention has an X-ray diffraction pattern with values described above, and has a bulk density of 0.05 g/ml to 0.15 g/ml, preferably 0.08 g/ml to 0.11 g/ml. The titanosilicate having such properties is a catalyst capable of producing an olefin oxide in a high yield.

Hereinafter, the catalyst containing the titanosilicate having the properties described above sometimes referred to as the "present catalyst". The present catalyst is very useful as a catalyst used in process for producing an olefin oxide, as described below.

[0010]

The titanosilicate refers to a compound in which some silicon atoms in the silicon dioxide backbone are replaced by titanium atoms.

The replacement of some silicon atoms in the silicon dioxide backbone by titanium atoms can be confirmed by appearance of the maximum absorption peak within a wavelength range of 210 nm to 230 nm, for an ultraviolet and visible absorption spectrum of the titanosilicate in a wavelength range of 200 nm to 400 nm (for example, see Chemical Communications 1026-1027, (2002) Figs. 2 (d) and (e) ) . The ultraviolet and visible absorption spectrum can be determined by using an ultraviolet and visible spectrophotometer provided with a diffuse reflecting device in accordance with a diffuse reflectance method.

[0011]

In the present catalyst, the titanosilicate has the following X-ray diffraction pattern.

X-ray diffraction pattern

(lattice spacing d/A)

12.4 ± 0.8

10.8 ± 0.5

9.0 ± 0.3

6.0 ± 0.3

3.9 ± 0.1

3.4 ± 0.1

The X-ray diffraction pattern can be determined by using an X-ray diffractometer using Cu K-alpha radiation. Detailed analysis conditions will be described in the Examples.

[0012]

The bulk density of the present catalyst can be determined in accordance with a tap density method. That is, the present catalyst is put in a graduated cylinder, and its weight is measured. Subsequently, the graduated cylinder is tapped until the volume of the present catalyst does not decrease any more. After tapping, the volume of the present catalyst is measured. From the weight and volume thus obtained, the bulk density (g/ml) is calculated.

[0013] As to a conventionally-used titanosilicate, primary particles densely agglomerate to form a secondary particle. On the other hand, as to the present catalyst, a secondary particle ( for example, about 2 μιτι to about 4 pm) in which primary particles of the titanosilicate aggregate to form an outer shell has an empty space in the inside. Accordingly, the present catalyst is considered to have a low bulk density.

The primary particle of the present catalyst may be a titanosilicate in a hexagonal plate shape. One side of the hexagonal plate is, for example, about 0.05 μιη to about 0. 2 urn, and the thickness of the hexagonal plate is, for example, about 10 nm to about 50 nm. An electron micrograph of the titanosilicate obtained in Example 1 described below is shown in Fig. 1 as a typical example.

[0014]

The present catalyst can be produced by, for example, a production method comprising the following first step and second step:

the first step: a step of heating a mixture containing a structure-directing agent, a compound containing an element belonging to Group 13 of the periodic table, a

titanium-containing compound, a silicon-containing compound and water to a temperature condition of at most lower than 155°C to obtain a solid; and

the second step: a step of bringing at least one selected from the group consisting of inorganic acids and titanium-containing compounds into contact with the solid obtained in the first step .

[0015]

Hereinafter, the compound containing an element belonging to Group 13 of the periodic table, the

silicon-containing compound, the titanium-containing compound and the structure-directing agent, which are used in the first step, will be described.

[0016]

Examples of the compound containing an element belonging to Group 13 of the periodic table (hereinafter sometimes referred to as a "Group 13 element-containing compound") include boron-containing compounds, aluminum-containing compounds and gallium-containing compounds.

Examples of the boron-containing compound include boric acid, borates, boron oxide; halogenated boron; and trialkyl boron-containing compounds having an alkyl group having 1 to 4 carbon atoms. Examples of the aluminum-containing compound include sodium aluminate, and examples of the

gallium-containing compound include gallium oxide.

As the Group 13 element-containing compound, the boron-containing compounds is preferable, and boric acid is more preferable.

[0017] Examples of the silicon-containing compound include silicic acid, silicates, silicon oxide, halogenated silicon, fumed silica, tetraalkyl orthosilicate and colloidal silica. As the silicon-containing compound, fumed silica is preferable.

[0018]

Examples of the titanium-containing compound include titanium alkoxides, organic acid salts of titanium, inorganic acid salts of titanium, halogenated titanium and titanium oxide .

The titanium alkoxide refers to a compound having an alkoxy group having 1 to 4 carbon atoms, and examples thereof include tetramethyl orthotitanate, tetraethyl orthotitanate, tetraisopropyl orthotitanate and tetra-n-butyl orthotitanate.

Examples of the organic acid salt of titanium include titanium acetate; examples of the inorganic acid salt of titanium include titanium nitrate, titanium sulfate, titanium phosphate, and titanium perchlorate; examples of halogenated titanium include titanium tetrachloride; and examples of titanium oxide include titanium dioxide.

As the titanium-containing compound, the titanium alkoxides are preferable, and tetra-n-butyl orthotitanate is more preferable.

The content of titanium atoms in the present catalyst is usually in a range of 0.005 mol to 0.05 mol, preferably 0.01 mol to 0.05 mol per mol of silicon atoms contained in the present catalyst .

In order to adjust the content of titanium atoms in the present catalyst, for example, each amount of the

titanium-containing compound and the silicon-containing compound used in the first step may be appropriately adjusted to give a predetermined content of titanium atoms within the range described above.

[0019]

The structure-directing agent means a

nitrogen-containing organic compound which contributes to the formation of a zeolite structure. Such a structure-directing agent can form a precursor of the zeolite structure by organizing polysilicate ions or polymetallosilicate ions around the agent (see "Zeoraito no Kagaku" (Science and Technology of Zeolites) , pp.33-34, 2000, Kodansha Scientific) .

Examples of the structure-directing agent include organic amines such as piperidine and hexamethyleneimine; and quaternary ammonium salts such as

N, N, -trimethyl-l-adamantane ammonium salts (e.g.

N, N, N-trimethyl-l-adamantane ammonium hydroxide,

N, N, N-trimethyl-l-adamantane ammonium iodide, and the like), and octyltrimethyl ammonium salts described in Chemistry Letters 916-917 (2007) (e . g. octyltrimethyl ammonium hydroxide, octyltrimethyl ammonium bromide, and the like) . The

structure-directing agents may be used alone, or as a mixture of two or more selected therefrom in an appropriate ratio.

Preferable structure-directing agents are piperidine, hexamethyleneimine, and mixture thereof.

[0020]

Next, the first step will be described.

The amount of water used in the first step may be adjusted to a range of 5 mol to 200 mol, preferably 10 mol to 50 mol per mol of silicon in the silicon-containing compound used in the first step.

[0021]

In the first step, the mixture containing the

structure-directing agent, the Group 13 element-containing compound, the titanium-containing compound, the

silicon-containing compound and water is put in a closed vessel such as an autoclave, and heated to a temperature in the range of at most lower than 155°C. The mixture is heated at a temperature in the range of preferably 100°C or higher and lower than 155°C, more preferably in the range of 130°C to 150°C. When the temperature is 100°C or higher, the crystallinity of the present catalyst tends to be excellent, and when it is lower than 155°C, the present catalyst having a bulk density of 0.15 g/ml or less can be obtained.

Here, the temperature range described above does not mean a temperature of an external surface of the closed vessel, it means a temperature indicated by a thermometer which is brought into contact with the mixture directly, or indirectly using a sheath tube or the like.

[0022]

The heating time in the first step is a time required for the solid obtained in the first step to show the above-described X-ray diffraction pattern. The heating time may be from 10 hours to 200 hours when the temperature is in a range of 100°C or higher and lower than 155°C, although this time may vary depending on the heating temperature and the amount of raw materials used.

[0023]

The mixture obtained in the first step can be subjected to solid-liquid separation by filtration or the like, whereby a solid can be obtained.

It is preferable to wash the obtained solid with water in order to remove unreacted raw materials such as the structure-directing agent, the Group 13 element-containing compound, the titanium-containing compound and the

silicon-containing compound therefrom, before it is subjected to the second step. Here, it is preferable to perform the washing until the washed liquid has a pH of 10 to 11.

It is preferable to dry the washed solid, for example, by through-air drying, drying under reduced pressure or vacuum-freeze drying until weight loss of the solid is no longer observed. [0024]

The second step is a step in which at least one selected from the group consisting of inorganic acids and

titanium-containing compounds is brought into contact with the solid obtained in the first step.

[0025]

Examples of the inorganic acid include sulfuric acid, hydrochloric acid, nitric acid, perchloric acid,

fluorosulfonic acid and mixtures thereof. Among these, preferred are nitric acid, perchloric acid, fluorosulfonic acid and mixtures thereof.

As to the inorganic acid, it is preferable to use it in the form of a solution in which the acid is mixed with a solvent. Examples of such solvent include water, alcohol solvents, ether solvents, ester solvents, ketone solvents and mixtures thereof, and among them, preferred is water.

The concentration of the inorganic acid in the solution may be in a range of 0.01 M to 20 M (M: the number of moles of the inorganic acid/the volume of the inorganic acid solution (L) ) , preferably 1 M to 5 M.

[0026]

Examples of the titanium-containing compound used in the second step include the same as the titanium-containing compounds used in the first step.

In the second step, the titanium-containing compound may be used in an amount of 10 parts by weight or less, preferably 0.01 part to 2 parts by weight per part by weight of the solid.

[0027]

The contact temperature in the second step may be in the range of 20°C to 150°C, preferably in the range of 50°C to 104°C .

The second step may be carried out under reduced pressure, normal pressure or increased pressure. Preferably, the second step is carried out under normal pressure or slightly increased pressure such as a gauge pressure of about 0 MPa to 10 MPa.

In addition, the second step is preferably carried out in the presence of a solvent. As the solvent, the solvents which are listed above as the solvents to be mixed with the inorganic acid are preferable.

[0028]

The present catalyst obtained in the second step has a layered structure, and a catalyst obtained by being subj ected to dehydration condensation is also the present catalyst and it is Ti-MW . Here, Ti-MWW means a titanosilicate having an MWW structure defined in the structure code of IZA

(International Zeolite Association) .

[0029]

The titanosilicate obtained in the second step is the present catalyst, and the titanosilicate obtained in the third step, that is, the titanosilicate obtained by heating the titanosilicate obtained in the second step at a temperature of from 250°C to 1000°C, is also the present catalyst.

[0030]

The third step will be specifically described. The third step may be a step in which the product obtained in the second step is put in a heating furnace such as an electric furnace, the temperature is elevated to from 250°C to 1000°C, preferably from 300°C to 600°C over 1 to 24 hours, the temperature is kept for 1 hour to 24 hours, and the product is allowed to cool naturally in the furnace.

It is preferred that the third step is carried out in a heating furnace under an atmosphere of an inert gas such as nitrogen, argon or helium; an oxidized gas such as air, oxygen and carbon dioxide; or a reducing gas such as hydrogen, carbon monoxide and propylene.

In the third step, the titanosilicate obtained in the second step is subjected to dehydration condensation.

[0031]

A titanosilicate obtained through a step in which the titanosilicate obtained in the second step or the third step is brought into contact with the structure-directing agent (hereinafter sometimes referred to as a "fourth step") is also the present catalyst.

[0032]

The operation of the fourth step will be specifically described. Examples of the operation include an operation in which the titanosilicate obtained in the second step or the titanosilicate obtained in the third step, the

structure-directing agent and optionally a solvent are put in a closed vessel such as an autoclave, and the mixture is pressurized with heating; an operation in which the

titanosilicate obtained in the second step or the

titanosilicate obtained in the third step, the

structure-directing agent and optionally a solvent are stirred and mixed in a container such as a glass flask under the atmosphere; and an operation in which the titanosilicate obtained in the second step or the titanosilicate obtained in the third step, the structure-directing agent and optionally a solvent are statically mixed in a container such as a glass flask under the atmosphere.

Examples of the solvent used in the fourth step include water, alcohol solvents, ether solvents, ester solvents, ketone solvents and mixtures thereof, among them, preferred is water.

As the structure-directing agent, the same

structure-directing agents as those used in the first step can be mentioned.

[0033]

The lower limit of the temperature at which the titanosilicate and the structure-directing agent are brought into contact with each other in the fourth step may be 0°C, preferably 20°C, more preferably 50°C, further more preferably 100°C. The upper limit of the temperature at which the titanosilicate and the structure-directing agent are brought into contact with each other in the fourth step may be 250°C, preferably 200°C, more preferably 180°C.

The titanosilicate and the structure-directing agent may be brought into contact with each other in the fourth step under normal pressure, reduced pressure or increased pressure. Preferably, they are brought into contact with each other under normal pressure or increased pressure such as a gauge pressure of from 0 Pa to 10 Pa. The titanosilicate obtained through the fourth step is separated through, for example, filtration. The separated solid may be further subj ected to a post-treatment such as washing or drying, if necessary.

[0034]

A titanosilicate obtained through a step in which the titanosilicate obtained in the second step, the third step or the fourth step is silylated with a silylating agent

(hereinafter sometimes referred to as a "fifth step") is also the present catalyst.

[0035]

The fifth step will be specifically described. The fifth step may be a step in which the titanosilicate obtained in the second step, the titanosilicate obtained in the third step, or the titanosilicate obtained in the fourth step is silylated with a silylating agent such as 1,1,1,3,3, 3-hexamethyldisilazane in accordance with the process described in EP 1488853 Al.

[0036]

A titanosilicate obtained through a step in which the titanosilicate obtained in the second step, the third step, the fourth step or the fifth step is brought into contact with hydrogen peroxide (hereinafter sometimes referred to as a "sixth step") is also the present catalyst.

The concentration of hydrogen peroxide used in the sixth step may be in a range of 0.0001% by weight to 50% by weight.

Examples of the solvent to be used to dilute the hydrogen peroxide include solvents listed in the fourth step, and preferable solvents are water, acetonitrile and mixed solvents thereof .

The temperature of the sixth step may be from 0°C to 100°C, preferably from 0°C to 60°C.

[0037]

The process for producing an olefin oxide of the present invention is a process using the present catalyst. That is, the process for producing an olefin oxide of the present invention comprises a step in which an olefin compound is oxidized with an oxidizing agent in the presence of the present catalyst (hereinafter sometimes refereed to as an "oxidation reaction" ) .

[0038]

The oxidizing agent means a compound capable of giving oxygen atoms to the olefin compound. Examples of the oxidizing agent include oxygen and peroxides. Examples of the peroxide include hydrogen peroxide and organic peroxides.

Examples of the organic peroxide include t-butyl hydroperoxide, di-t-butyl peroxide, t-amyl hydroperoxide,■ cumene hydroperoxide, methylcyclohexyl hydroperoxide, tetralin hydroperoxide, isobutylbenzene hydroperoxide, ethylnaphthalene hydroperoxide, and peracetic acid. The oxidizing agents may be a mixture of two or more selected from the above-mentioned peroxides.

As the hydrogen peroxide, a commercially available product may be used. And also the hydrogen peroxide may be prepared from oxygen and hydrogen in the presence of a noble metal in the same reaction system as that of the oxidation reaction.

The oxidizing agent is preferably peroxides, more preferably hydrogen peroxide, especially preferably an aqueous solution of hydrogen peroxide having a concentration in the range of 0.0001% by weight or more and less than 100% by weight.

[0039]

The amount of the oxidizing agent used in the oxidation reaction can be properly selected according to the kind of the olefin compound and the reaction conditions, and it is, for example, 0.01 part by weight or more, more preferably 0.1 part by weight or more per 100 parts by weight of the olefin compound. The upper limit of the amount of the oxidizing agent used may be 1000 parts by weight, preferably 100 parts by weight per 100 parts by weight of the olefin compound.

[0040]

The olefin compound used in the oxidation reaction refers to a compound in which a hydrocarbyl group optionally having a substituent or hydrogen is bonded to a carbon atom which forms an olefin double bond.

Examples of the hydrocarbyl group include saturated hydrocarbyl groups, and examples of the saturated hydrocarbyl group include alkyl groups. Examples of the substituent which the hydrocarbyl group may have include a hydroxyl group, a halogen atom, a carbonyl group, an alkoxycarbonyl group, a cyano group and a nitro group.

Specific examples of the olefin compound include alkenes having 2 to 10 carbon atoms, and cycloalkenes having 4 to 10 carbon atoms.

Examples of the alkene having 2 to 10 carbon atoms 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 .

Examples of the cycloalkene having 4 to 10 carbon atoms include cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclononene and cyclodecene. In the present invention, as the olefin compound, alkenes having 2 to 10 carbon atoms are preferable, alkenes having 2 to 5 carbon atoms are more preferable, and propylene is further more preferable.

[0041]

In the oxidation reaction, the amount of the olefin compound used can be properly selected according to the kind thereof and the reaction conditions. The amount of the olefin compound may be 0.01 part by weight or more, more preferably 0.1 part by weight or more per 100 parts by weight of the total amount of the reaction solution in the oxidation reaction. The upper limit of the amount of the olefin compound may be 1000 parts by weight, preferably 100 parts by weight per 100 parts by weight of the total amount of the reaction solution.

[0042]

The oxidation reaction is preferably carried out in the presence of a solvent. Examples of the solvent include water, organic solvents and a mixture thereof.

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 aliphatic hydrocarbon solvent include aliphatic hydrocarbons having 5 to 10 carbon atoms such as hexane and heptane. Examples of the aromatic hydrocarbon solvent include aromatic hydrocarbon solvents having 6 to 15 carbon atoms such as benzene, toluene and xylene.

Examples of the alcohol solvent include monohydric alcohols having 1 to 6 carbon atoms and glycols having 2 to 8 carbon atoms. As the alcohol solvent, aliphatic alcohols having 1 to 8 carbon atoms are preferable, monohydric alcohols having 1 to 4 carbon atoms such as methanol, ethanol, isopropanol and t-butanol are more preferable, and t-butanol is further more preferable.

Examples of the nitrile solvent include alkyl nitriles having 2 to 4 carbon atoms such as acetonitrile, propionitrile, isobutyronitrile and butyronitrile, and benzonitrile . Among them, preferred is acetonitrile.

As the solvent used in the oxidation reaction, water, alcohol solvents, nitrile solvents and mixed solvents thereof are preferable from a viewpoint of the catalyst activity and selectivity.

[0043]

In the oxidation reaction, the amount of the present catalyst may be properly selected according to the kind of the olefin compound. The lower limit of the amount may be 0.01 part by weight, preferably 0.1 part by weight, more preferably 0.5 part by weight per 100 parts by weight of the total amount of the solvent. The upper limit thereof may be 20 parts by weight, preferably 10 parts by weight, more preferably 8 parts by weight per 100 parts by weight of the total amount of the solvent.

[0044]

The lower limit of the reaction temperature in the oxidation reaction may be 0°C, preferably 40°C. The upper limit thereof may be 200°C, preferably 150°C.

The lower limit of the reaction pressure in the oxidation reaction may be 0.1 MPa, preferably 1 MPa. The upper limit thereof may be 20 MPa, preferably 10 MPa.

[0045]

In the oxidation reaction, when hydrogen peroxide is used as the oxidizing agent, hydrogen peroxide produced in the same reaction system as that of the oxidation reaction may be supplied.

When hydrogen peroxide is produced in the same reaction system as that of the oxidation reaction, hydrogen peroxide can be synthesized, for example, from oxygen and hydrogen in the presence of a noble metal catalyst.

Examples of the noble metal catalyst include noble metals such as palladium, platinum, ruthenium, rhodium, iridium, osmium and gold, and alloys and mixtures thereof. Preferable noble metals are palladium, platinum and gold. Palladium is a more preferable noble metal. As palladium, for example, palladium colloid may be used (see, for example, JP 2002-294301 A, Example 1, etc. ) . As the noble metal catalyst, a noble metal compound capable of being converted into a noble metal by reduction in the oxidation reaction system may be used.

[0046]

When palladium is used as the noble metal catalyst, it is possible to use a mixture of palladium and a metal other than palladium, such as platinum, gold, rhodium, iridium or osmium. Preferable metals other than palladium are gold and platinum.

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 acetylacetonate (II), dichlorobis (benzonitrile) palladium (II), dichlorobis (acetonitrile) palladium (II),

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

dichlorotetraammine palladium (II), dibromotetraammine palladium (II), dichloro (cycloocta-1, 5-diene) palladium (II), and palladium trifluoroacetate (II) .

[0047]

The noble metal is usually used in the state where it is supported on a support. The noble metal may be supported on the present catalyst and the resulting product may be used, or the noble metal may be supported on an oxide such as silica, alumina, titania, zirconia or niobia, a hydrate of niobic acid, zirconic acid, tungstic acid, titanic acid or the like, carbon, or a mixture thereof, and the resulting product may be used. When the noble metal is supported on a support other than the present catalyst, the support which supports the noble metal may be mixed with the present catalyst, and the resulting mixture may be used as the catalyst.

When a support other than the present catalyst is used, carbon is preferably used as a support. As the carbon support, for example, activated carbon, carbon black, graphite and carbon nanotube are known.

[0048]

As a process for preparing the noble metal catalyst, for example, a process in which the noble metal compound is supported on the support and then the product is reduced, is known. For carrying the noble metal compound, conventionally known methods such as an impregnation method may be used.

The reduction may be carried out using a reducing agent such as hydrogen, or using an ammonia gas which is generated upon thermal decomposition in an inert gas atmosphere. The reduction temperature may vary depending on the kind of the noble metal compound, and is preferably from 100°C to 500°C, more preferably from 200°C to 350°C.

The noble metal catalyst contains the noble metal in an amount in a range of, for example, 0.01% by weight to 20% by weight, preferably 0.1% by weight to 5% by weight. The weight ratio of the noble metal to the present catalyst (the weight of the noble metal/the weight of the present catalyst) is preferably from 0.01% by weight to 100% by weight, more preferably from 0.1% by weight to 20% by weight .

[0049]

In the oxidation reaction, it is preferable to put a buffer in the oxidation reaction system, because the conversion and yield of the olefin oxide relative to the oxidizing agent tend to be improved. Here, the buffer refers to a compound comprising anions and cations which are capable of providing a pH buffer action.

In general, the buffer is dissolved in the oxidation reaction system, but when hydrogen peroxide produced in the same reaction system is used as the oxidizing agent, the buffer may be previously contained in the noble metal catalyst. As such a method, for example, a method in which after an ammine complex such as Pd-tetraammine chloride is supported on the support by impregnation or the like, the resulting product is reduced and ammonium ions are left, and the buffer is generated during the oxidation reaction, is exemplified.

The amount of the buffer added may be in the range of 0.001 mmol/kg to 100 mmol/kg per kg of the solvent.

[0050]

Examples of the buffer include buffers comprising 1) an anion 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 carboxylate ion having 1 to 10 carbon atoms, and 2) a cation selected from the group consisting of an ammonium, an alkyl ammonium having 1 to 20 carbon atoms, an alkyl aryl ammonium having 7 to 20 carbon atoms, an alkali metal and an alkaline earth metal. Examples of the 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 and the 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.

Preferable examples of the buffer include ammonium salts of 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 ammonium salts of carboxylic acids such as ammonium acetate. Among them, ammonium dihydrogen phosphate is preferable.

[0051]

In the oxidation reaction, when hydrogen peroxide synthesized from oxygen and hydrogen in the reaction system is used as the oxidizing agent, it is preferable to incorporate a quinoid compound in the oxidation reaction system because the selectivity of the olefin oxide tends to increase. The quinoid compound may be a p-quinoid compound and an o-quinoid compound represented by the following formula (1) :

Y

wherein R¹, R², R³ and R⁴ are each a hydrogen atom; or R¹ and R², or R³ and R⁴, are bonded to each other at the ends thereof to form an optionally substituted naphthalene ring together with carbon atoms to which they attach; and X and Y are the same or different and represent an oxygen atom or a NH group.

[0052]

Examples of the compound of the formula (1) include 1) a quinone compound (1A) represented by the formula (1) in which R¹, R², R³ and R⁴ are each a hydrogen atom, and both X and Y are each an oxygen atom;

2) a quinoneimine compound (IB) represented by the formula (1) in which R¹, R², R³ and R⁴ are each a hydrogen atom, X is an oxygen atom, and Y is an NH group; and

3) a quinonediimine compound (1C) represented by the formula (1) in which R¹, R², R³ and R⁴ are each a hydrogen atom, and X and Y are each a NH group.

[0053]

The quinoid compound represented by the formula (1) includes the following anthraquinone compound (2) :

Y

wherein X and Y mean the same as defined in the formula (1), R⁵, R⁶, R⁷ and R⁸ are the same or different, and each is a hydrogen atom, a hydroxy group or an alkyl group such as Ci-C₅ alkyl groups. Examples of the C1-C5 alkyl group include a methyl group, an ethyl group, a propyl group, a butyl group and a pentyl group.

[0054]

In the formula (1) and the formula (2), X and Y are each preferably an oxygen atom.

Examples of the quinoid compound include benzoquinone, naphthoquinone, anthraquinone, alkyl anthraquinone compounds, polyhydroxyanthraquinone and 9, 10-phenanthraquinone .

Examples of the alkyl anthraquinone compound include 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; and polyalkyl anthraquinone compounds such as 1,3-diethyl anthraquinone, 2,3-dimethyl anthraquinone, 1,4-dimethyl anthraquinone and 2,7-dimethyl anthraquinone.

Examples of the polyhydroxyanthraquinone include

2, 6-dihydroxyanthraquinone .

[0055]

Preferable examples of the quinoid compound include anthraquinone, and 2-alkyl anthraquinone compounds

represented by the formula (2) in which X and Y are each an oxygen atom, R⁵ is an alkyl group which is substituted at the 2-position, R⁶ is a hydrogen atom, and R⁷ and R⁸ are each a hydrogen atom.

The amount of the quinoid compound used in the oxidation reaction may be from 0.001 mmol/kg to 500 mmol/kg per kg of the solvent, and preferably from 0.01 mmol/kg to 50 mmol/kg.

According to the process for producing an olefin oxide of the present invention, it is also possible to add a salt containing an ammonium, an alkyl ammonium or an alkyl aryl ammonium to the oxidation reaction system at the same time. [0056]

The quinoid compound can also be prepared by oxidizing a dihydro form of the quinoid compound in the oxidation reaction system using oxygen or the like. For example, a quinoid compound such as hydroquinone or 9, 10-anthracene diol which has been hydrogenated may be added to the oxidation reaction system and oxidized with oxygen in the reaction vessel to generate a quinoid compound, and the resulting quinoid compound may be used .

Examples of the dihydro form of the quinoid compound include compounds represented by the following formulae (3) and (4), which are the dihydro forms of the compounds represented by the formulae (1) and (2) :

wherein R¹, R², R³, R⁴, X and Y mean the same as defined in the formula (1) :

YH

wherein X, Y, R⁵, R⁶, R⁷ and R⁸ mean the same as defined in the formula (2) .

In the formulae (3) and (4) , X and Y are each preferably an oxygen atom.

Preferable examples of the dihydro form of the quinoid compound include dihydro forms corresponding to the preferable quinoid compounds described above.

[0057]

Any chemical reaction process such as a continuous system, a batch system or a semi-batch system is applicable to the oxidation reaction. Preferably, the oxidation reaction is carried out in a batch system or a semi-batch system.

[0058]

In the case of a reaction in which the olefin compound is oxidized with a peroxide which has been previously produced, the reaction gas atmosphere is not limited.

[0059]

When hydrogen peroxide is produced from oxygen and hydrogen in the same reaction system as that of the oxidation reaction, the partial pressure ratio of oxygen to hydrogen which are supplied to the reaction system may be in a range of, for example, oxygen : hydrogen =1 : 50 to 50 : 1, preferably 1 : 2 to 10 : 1. When the partial pressure ratio of oxygen to hydrogen (oxygen/hydrogen) is 50/1 or less, the generation speed of the olefin oxide tends to increase. On the other hand, when the partial pressure ratio of oxygen to hydrogen

(oxygen/hydrogen) is 1/50 or more, generation of by-products such as alkane compounds which are produced by reduction of the olefin compound decreases, and thus the selectivity of the olefin oxide tends to increase.

[0060]

Here, oxygen and hydrogen may be diluted. Examples of the gas used for dilution include nitrogen, argon, carbon dioxide, methane, ethane and propane . The concentration of the dilution gas is not limited, and, if necessary, the synthesis reaction of hydrogen peroxide is carried out after diluting oxygen or hydrogen.

Oxygen may be used as it is, or a mixed gas such as air or a mixed gas of oxygen and the gas used for dilution described above may be used. An oxygen gas which is produced by an inexpensive pressure swing method may be used, or, if necessary, a high purity oxygen gas which is produced by cryogenic separation may also be used as the oxygen gas.

[0061] The reaction temperature of the oxidation reaction may be 0°C to 200°C, preferably 40°C to 150°C.

When the reaction temperature is 0°C or more, the reaction speed tends to increase. When the reaction temperature is 200°C or less, side reactions are inhibited and the selectivity of the alkylene oxide tends to increase.

[0062]

The oxidation reaction may be carried out under increased pressure, for example, under a gauge pressure of 0.1 Pa to 20 MPa, preferably 1 MPa to 10 MPa.

[0063]

After the completion of the oxidation reaction, for example, the olefin oxide can be taken out by distillation of the reaction product of the oxidation reaction.

EXAMPLES

[0064]

In the following, the present invention will be described in more detail by way of Examples.

<Analyzer and Analysis Method>

(Elemental Analysis)

Weights of Ti (titanium atoms) and Si (silicon atoms) contained in the present catalyst were measured by the ICP emission spectrometry. That is, about 20 mg of a sample was measured into a platinum crucible, and the sample was covered with sodium carbonate. After that, melting operation was carried out by using a gas burner. After melting, the content in the platinum crucible was dissolved in pure water and nitric acid with heating. Subsequently, the volume thereof was fixed with pure water. Then, this solution was analyzed with the ICP emission spectrometer (ICPS-8000 manufactured by Shimadzu Corporation) , and an amount of each element was quantified.

[0065]

(Powder X-ray diffractometry (XRD) )

A powder X-ray diffraction pattern of the present catalyst was determined by using the following device under the following conditions.

Device: RINT 2500 V manufactured by Rigaku Denki Co., Ltd. Radiation Source: Cu K-a radiation

Output 40 kV-300 mA

Scanning Field: 2Θ = 0.75° to 30°

Scanning Speed: l°/minute

[0066]

(Ultraviolet and Visible Absorption Spectrum (UV-Vis) )

The present catalyst was thoroughly pulverized in an agate mortar, and formed into pellets (7mm<j) ) to prepare a sample for measurement. An ultraviolet and visible absorption spectrum of the sample was determined by using the following device under the following conditions.

Device: a diffusion reflector (Praying Mantis manufactured by HARRICK)

Device Accessory: an ultraviolet and visible spectrophotometer (V-7100 manufactured by JASCO Corporation)

Pressure: atmospheric pressure

Measured Value: reflectance

Data Acquisition Time: 0.1 second

Band Width: 2 nm

Measurement Wavelength: 200 nm to 900 nm

Height of Slit: semi-open

Data Acquisition Interval: 1 nm

Baseline Correction (Reference) : BaS0₄ pellets (7 mm<|>)

[0067]

(Measurement of Bulk Density of Present Catalyst)

About 5 ml of the present catalyst, which had been thoroughly pulverized in a mortar, was precisely weighed and put in a 10 ml graduated cylinder, and vibration was applied to the graduated cylinder until the volume of the present catalyst did not change . The bulk density (g/ml) of the present catalyst was obtained from the weight (g) of the weighed present catalyst and the volume (ml) of the present catalyst which measured with the scale of the graduated cylinder.

[0068]

(Example 1)

In an autoclave, 899 g of piperidine (manufactured by Wako Pure Chemical Industries, Ltd. ) , 2402 g of ion-exchanged water, 46.4 g of TBOT (tetra-n-butyl orthotitanate, manufactured by ako Pure Chemical Industries, Ltd.)_/ 565 g of boric acid (manufactured by Wako Pure Chemical Industries, Ltd. ) , and 410 g of fumed silica (cab-o-sil M7D manufactured by Cabot

Corporation) were dissolved with stirring at 25°C to obtain a gel. After the gel was stirred for another 1.5 hours, the autoclave was sealed. Subsequently, the temperature of the gel was elevated to 150°C over 8 hours with stirring, and the gel was kept at that temperature for 120 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until its pH reached 10.3. The obtained solid was dried at 50°C until weight loss thereof was no longer observed to obtain 524 g of Solid 1.

To 75 g of Solid 1 were added 3750 mL of 2 M nitric acid and 9.5 g of TBOT (manufactured by Wako Pure Chemical Industries, Ltd.), and then the mixture was refluxed for 20 hours with heating. Subsequently, the obtained solid product was filtered, the filtrate was washed with water until its pH reached 5 or more, and then the solid product was dried in vacuum at 150°C with heating until weight loss thereof was no longer observed to obtain 59 g of a white powder (Catalyst A) . It was confirmed that the X-ray diffraction pattern of Catalyst A had peaks at 12.3 d/A, 11.0 d/A, 9.0 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that the product was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 1.99% by weight . In addition, Catalyst A had a bulk density of 0.10 g/ml.

[0069]

(Example 2)

50 g of Catalyst A obtained in Example 1 was heated at

530°C for 6 hours to obtain 45 g of powdery Catalyst B. It was confirmed that the X-ray diffraction pattern of Catalyst B had peaks at 12.3 d/A, 11.0 d/A, 9.0 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A. It was also found that Catalyst B was titanosilicate from the ultraviolet and visible absorption spectrum. In addition, Catalyst B had a bulk density of 0.11 g/ml.

[0070]

(Example 3)

In an autoclave, 899 g of piperidine (manufactured by Wako Pure Chemical Industries, Ltd. ) , 2402 g of ion-exchanged water, 46 g of TBOT (manufactured by Wako Pure Chemical Industries, Ltd. ) , 565 g of boric acid (manufactured by Wako Pure Chemical Industries, Ltd.), and 410 g of fumed silica (cab-o-sil 7D manufactured by Cabot Corporation) were dissolved with stirring at 25°C to obtain a gel. After the gel was stirred for another 1.5 hours, the autoclave was sealed. Subsequently, the temperature of the gel was elevated to 145°C over 8 hours with stirring, and the gel was kept at that temperature for 120 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until its pH reached 10.5. The obtained solid was dried at 50°C until weight loss thereof was no longer observed to obtain 508 g of Solid 2.

To 15 g of Solid 2 were added 750 mL of 2 M nitric acid and 1.9 g of TBOT (manufactured by Wako Pure Chemical Industries, Ltd. ) , and then the mixture was refluxed for 20 hours with heating. Subsequently, the obtained solid product was filtered, the filtrate was washed with water until its pH reached 5 or more, and then the solid product was dried in vacuum at 150°C with heating until weight loss thereof was no longer observed to obtain 11.3 g of a white powder (Catalyst C) . It was confirmed that the X-ray diffraction pattern of Catalyst C had peaks at 12.3 d/A, 11.0 d/A, 9.0 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that Catalyst C was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 1.89% by weight . In addition, Catalyst C had a bulk density of 0.09 g/ml .

[0071]

(Example 4)

In an autoclave, 300 g of piperidine (manufactured by Koei

Chemical Company Limited) , 600 g of ion-exchanged water, and 80 g of Catalyst B obtained in Example 2 were dissolved with stirring at 25°C to obtain a gel. After the gel was stirred for another 1.5 hours, the autoclave was sealed. Subsequently, the temperature of the gel was elevated to 160°C over 4 hours with stirring, and the gel was kept at that temperature for 24 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until the pH of the filtrate reached 10.5, and then the obtained solid product was dried at 150°C in vacuum with heating until weight loss thereof was no longer observed to obtain 79 g of a white powder (catalyst D) . It was confirmed that the X-ray diffraction pattern of Catalyst D had peaks at 12.3 d/A, 11.1 d/A, 9.0 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that Catalyst D was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 2.08% by weight. In addition, Catalyst D had a bulk density of 0.09 g/ml.

[0072]

(Example 5)

Catalyst D was silylated with reference to the method described in JP 2003-326171 A. That is, the silylation was carried out by mixing 1.0 g of 1, 1, 1, 3, 3, 3-hexamethyl disilazane (manufactured by Wako Pure Chemical Industries, Ltd.), 100 mL of toluene (manufactured by Wako Pure Chemical Industries, Ltd.) and 0.5 g of Catalyst D, and refluxing the mixture for 3 hours with heating. Then, after the obtained reaction mixture was filtered, the obtained solid was washed sequentially with 500 ml of acetone and 1 L of a mixed solvent of water/acetonitrile (= 1/4, a mass ratio), and the washed solid product was dried in vacuum at 150°C until weight loss thereof was no longer observed to obtain 0.50 g of a white powder (Catalyst E) . It was confirmed that the X-ray diffraction pattern of Catalyst E had peaks at 12.5 d/A, 11.2 d/A, 9.1 d/A, 6.2 d/A, 3.9 d/A and 3.4 d/A, and it was found that Catalyst E was titanosilicate from the ultraviolet and visible absorption spectrum. Catalyst E had a bulk density of 0.08 g/ml .

[0073]

(Reference Example 1)

A Ti-MWW precursor was synthesized in the same manner as described in Chemistry Letters 774-775 (2000) . That is, 200 g of piperidine (manufactured by Wako Pure Chemical Industries, Ltd. ) and 564 g of ion-exchanged water were mixed in a 2-L resin beaker at 25°C under an air atmosphere to obtain an aqueous piperidine solution. The aqueous solution was divided into two portions 382 g each, whereby an aqueous piperidine solution (1) and an aqueous piperidine solution (2) were prepared.

The aqueous piperidine solution (1), 5.6 g of TBOT (manufactured by Wako Pure Chemical Industries, Ltd.), and 49.5 g of fumed silica (cab-o-sil M7D manufactured by Cabot Corporation) were stirred at 25°C under an air atmosphere to obtain Gel (1) . Gel (1) was stirred for 1 hour.

Meanwhile, the aqueous piperidine solution (2), 136.5 g of boric acid (manufactured by Wako Pure Chemical Industries, Ltd. ) , and 49.5 g of fumed silica (cab-o-sil M7D, manufactured by Cabot Corporation) were stirred at 25°C under an air atmosphere to obtain Gel (2) . Gel (2) was stirred for 1 hour.

Gel (1) and Gel (2) were mixed in an autoclave at 25°C under an air atmosphere, and the mixture was stirred for another 1.5 hours to obtain Gel (3) . The composition (molar) ratio of the mixture in Gel (3) was Si0₂ : Ti0₂ : B₂0₃ : piperidine : H₂0 = 1 : 0.01 : 0.67 : 1.4 : 19. The autoclave was sealed, the temperature of the content was elevated to 130°C over 5.5 hours while the mixture was stirred at a rotating speed of 100 rpm, and the content was kept at that temperature for 24 hours . After the content was kept at 130°C, the temperature of the content was elevated to 150°C over 1 hour, and the content was kept at that temperature for 24 hours. After the content was kept at 150°C, the temperature of the content was elevated to 170°C over 1 hour, and the content was kept at that temperature for 120 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until its pH reached 10.0. The obtained solid was dried at 50°C until weight loss thereof was no longer observed to obtain 117 g of Solid 3.

To 3 g of Solid 3 was added 60 mL of 2 M nitric acid, and the mixture was kept at 100°C for 20 hours while being stirred. Subsequently, the obtained solid product was filtrated, and the filtrate was washed with water until its pH reached 5 or more, and then the solid product was dried in vacuum at 150°C until weight loss thereof was no longer observed to obtain 2.3 g of a white powder (Catalyst 1) . It was confirmed that the X-ray diffraction pattern of Catalyst 1 had peaks at 12.3 d/A, 11.0 d/A, 8.8 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that the product was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 0.76% by weight. In addition, Catalyst 1 had a bulk density of 0.18 g/ml.

[0074]

(Reference Example 2)

In an autoclave, 899 g of piperidine (manufactured by Wako Pure Chemical Industries, Ltd. ) , 2402 g of ion-exchanged water, 47 g of TBOT (manufactured by Wako Pure Chemical Industries, Ltd.) , 565 g of boric acid (manufactured by Wako Pure Chemical Industries, Ltd.) and 410 g of fumed silica (cab-o-sil M7D, manufactured by Cabot Corporation) were dissolved with stirring at 25°C to obtain a gel. After the gel was stirred for another 1.5 hours, the autoclave was sealed. Subsequently, the temperature of the gel was elevated to 160°C over 8 hours with stirring, and the gel was kept at that temperature for 120 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until its pH reached 10.4. The obtained solid was dried at 50°C until weight loss thereof was no longer observed to obtain 508 g of Solid 4.

To 75 g of Solid 4 were added 3750 ml of 2 M nitric acid and 9.5 g of TBOT (manufactured by Wako Pure Chemical Industries, Ltd.), and then the mixture was refluxed for 20 hours with heating. Subsequently, the obtained solid product was filtered, the filtrate was washed with water until its pH reached 5 or more, and then the solid product, which had been washed with water, was dried in vacuum with heating up to 150°C until weight loss thereof was no longer observed to obtain 56 g of a white powder (Catalyst 2) . It was confirmed that the X-ray diffraction pattern of Catalyst 2 had peaks at 12.3 d/A, 11.0 d/A, 9.0 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that the product was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 1.89% by weight. In addition, Catalyst

2 had a bulk density of 0.35 g/ml.

[0075]

(Reference Example 3)

50 g of Catalyst 1 obtained in Reference Example 1 was heated at 530°C for 6 hours to obtain 45 g of Catalyst 3. It was confirmed that the X-ray diffraction pattern of Catalyst

3 had peaks at 12.3 d/A, 11.0 d/A, 8.9 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that the product was titanosilicate from the ultraviolet and visible absorption spectrum. In addition, Catalyst 3 had a bulk density of 0.35 g/ml. [0076]

(Reference Example 4)

In an autoclave, 899 g of piperidine (manufactured by Wako Pure Chemical Industries, Ltd. ) , 2402 g of ion-exchanged water, 899 g of TBOT (manufactured by Koei Chemical Company Limited) , 565 g of boric acid (manufactured by Yoneyama Chemical Industry Co., Ltd.), and 410 g of fumed silica (cab-o-sil M7D, manufactured by Cabot Corporation) were dissolved with stirring at 25°C to obtain a gel. After the gel was stirred for another 1.5 hours, the autoclave was sealed. Subsequently, the temperature of the gel was elevated to 160°C over 8 hours with stirring, and the gel was kept at that temperature for 120 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until its pH reached 10.5. The obtained solid was dried at 50°C until weight loss thereof was no longer observed to obtain 508 g of Solid 5.

To 75 g of Solid 5 was added 3750 mL of 2 M nitric acid, and then the mixture was refluxed for 20 hours with heating. Subsequently, the obtained solid product was filtered, the filtrate was washed with water until its pH reached 5 or more, and then the solid product, which had been washed with water, was dried in vacuum with heating up to 150°C until weight loss thereof was no longer observed to obtain 52 g of a white powder (Catalyst 4) . It was confirmed that the X-ray diffraction pattern of Catalyst 4 had peaks at 12.3 d/A, 11.0 d/A, 8.9 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that the product was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 1.80% by weight . In addition, Catalyst 4 had a bulk density of 0.40 g/ml.

[0077]

(Reference Example 5)

50 g of Catalyst 4 obtained in Reference Example 4 was heated at 530°C for 6 hours to obtain 45 g of Solid 6. It was confirmed that the solid had an MWW structure by determining the X-ray diffraction pattern of Solid 6 and comparing the pattern with Fig. 2 disclosed in JP 2005-262164 A. It was also found that the product was titanosilicate from the ultraviolet and visible absorption spectrum.

In an autoclave, 45 g of piperidine (manufactured by Wako Pure Chemical Industries, Ltd.), 90 g of ion-exchanged water and 15 g of Solid 6 were dissolved with stirring at 25°C to obtain a gel. After the gel was stirred for another 1.5 hours, the autoclave was sealed. Subsequently, the temperature of the gel was elevated to 160°C over 4 hours with stirring, and the gel was kept at that temperature for 16 hours to obtain a suspension. After the obtained suspension was filtered, the filtrate was washed with water until its pH reached 9.3. The obtained solid was dried at 50°C until weight loss thereof was no longer observed to obtain 13.5 g of Catalyst 5. It was confirmed that the X-ray diffraction pattern of Catalyst 5 had peaks at 12.3 d/A, 11.1 d/A, 9.0 d/A, 6.1 d/A, 3.9 d/A and 3.4 d/A, and it was found that the product was titanosilicate from the ultraviolet and visible absorption spectrum. The titanium content measured by elemental analysis was 1.80% by weight . In addition, Catalyst 5 had a bulk density of 0.39 g/ml.

[0078]

(Hydrogen Peroxide Treatment)

The titanosilicates obtained in examples of the present invention and reference examples were brought into contact with hydrogen peroxide in accordance with the following method.

A mixture of 100 g of a solution of water/acetonitrile = 1/4 (weight ratio) containing 0.1 g of titanosilicate and 0.1% by weight of hydrogen peroxide was stirred at room temperature (about 20°C) for 1 hour, filtered, and the obtained cake was washed with 500 mL of water to obtain a titanosilicate treated with hydrogen peroxide.

[0079]

(Production Example 1 of Propylene Oxide: Example 6)

A solution of 0.5% by weight of hydrogen peroxide in a mixed solvent of acetonitrile/water (acetonitrile/water = 4/1 (weight ratio) ) was prepared by mixing an aqueous solution containing 30% by weight of hydrogen peroxide (manufactured by Wako Pure Chemical Industries, Ltd.) with acetonitrile (manufactured by Nacalai Tesque Inc. ) and ion-exchanged water. A 100 mL-stainless steel autoclave was filled with 60 g of the prepared solution, and 0.010 g of Catalyst A', which was separately obtained by treating Catalyst A from Example 1 with hydrogen peroxide as described above. Subsequently, the autoclave was put in an ice bath, to which 1.2 g of propylene was added. The pressure inside the autoclave was increased to 2 MPa (gauge pressure) with argon. The temperature thereof was elevated to 60°C over 15 minutes while the mixed liquid in the autoclave was stirred, and the mixed liquid was stirred at that temperature for 1 hour. Then, the stirring was stopped, and the autoclave was cooled with ice.

After that, the obtained mixed liquid was analyzed by gas chromatography. As a result, the yield of propylene oxide was 49% based on the amount of hydrogen peroxide.

[0080]

(Production Example 2 of Propylene Oxide2: Example 7)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst B', which was obtained by treating Catalyst B from Example 2 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 54% based on the amount of hydrogen peroxide.

[0081]

(Production Example 3 of Propylene Oxide: Example 8)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst C, which was obtained by treating Catalyst C from Example 3 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 51% based on the amount of hydrogen peroxide.

[0082]

(Production Example 4 of Propylene Oxide: Example 9)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst D', which was obtained by treating Catalyst D from Example 4 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 63% based on the amount of hydrogen peroxide.

[0083]

(Production Example 5 of Propylene Oxide: Example 10)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst E', which was obtained by treating Catalyst E from Example 5 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 77% based on the amount of hydrogen peroxide.

[0084]

(Reference Production Example 1 of Propylene Oxide: Use of Catalyst 1 from Reference Example 1)

Propylene oxide was produced in the same manner as in Example 6 except that 0.020 g of Catalyst 1, which was obtained in Reference Example 1, was used instead of 0.010 g of Catalyst A' . As a result, the yield of propylene oxide was 20% based on the amount of hydrogen peroxide.

[0085]

(Reference Production Example 2 of Propylene Oxide: Use of catalyst obtained by treating Catalyst 1 from Reference Example 1 with hydrogen peroxide)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst 1', which was obtained by treating Catalyst 1 from Reference Example 1 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 29% based on the amount of hydrogen peroxide .

[0086]

(Reference Production Example 3 of Propylene Oxide: Use of catalyst obtained by treating Catalyst 2 from Reference Example 2 with hydrogen peroxide)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst 2¹ , which was obtained by treating Catalyst 2 from Reference Example 2 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 42% based on the amount of hydrogen peroxide .

[0087]

(Reference Production Example 4 of Propylene Oxide: Use of catalyst obtained by treating Catalyst 3 from Reference Example 3 with hydrogen peroxide) Propylene oxide was produced in the same manner as in Example 6 except that Catalyst 3', which was obtained by treating Catalyst 3 from Reference Example 3 with hydrogen peroxide, was used instead of Catalyst A¹. As a result, the yield of propylene oxide was 38% based on the amount of hydrogen peroxide .

[0088]

(Reference Production Example 5 of Propylene Oxide: Use of catalyst obtained by treating Catalyst 4 from Reference Example 4 with hydrogen peroxide)

Propylene oxide was produced in the same manner as in Example 6 except that Catalyst 4 ' , which was obtained by treating Catalyst 4 from Reference Example 4 with hydrogen peroxide, was used instead of Catalyst A' . As a result, the yield of propylene oxide was 43% based on the amount of hydrogen peroxide .

[0089]

(FE-SEM Observation of Catalyst A and Catalyst 1)

Electron micrographs of Catalyst A obtained in Example 1 and Catalyst 1 obtained in Reference Example 1 were taken under the following measurement conditions. From Fig. 1, it can be understood that Catalyst A is in the form of hollow secondary particles, and from Fig. 2, it can be understood that the secondary particles of Catalyst 1 are particles resulting from mere aggregation of primary particles. (Measurement Conditions)

Measurement Device: Field emission-scanning electron microscope (FE-SEM) S-5500 manufactured by Hitachi

High-Technologies Corporation

Observation Conditions: A dark-field scanning transmission image (STEM-DF image) was observed at an acceleration voltage of 30 kV.

Pre-treatment method: A sample was mixed with a cold setting epoxy resin (Epocure) , and the mixture was degassed and thus the sample was embedded. A specimen having a film thickness of 80 to 100 nm was prepared by using Microtome (Ultramicrotome EMUC 6 manufactured by LEICA) (normal temperature and wet type) , and the sample was collected on a Cu mesh for observation.

[Industrial Applicability]

[0090]

The present invention can provide a novel titanosilicate as a catalyst for producing an olefin oxide capable of giving a higher yield based on the amount of an oxidizing agent.

Claims

1. A titanosilicate having a bulk density of 0.05 g/ml to 0.15 g/ml, and having an X-ray diffraction pattern with the following values:

lattice spacing d/A

12.4 ± 0.8

10.8 ± 0.5

9.0 ± 0.3

6.0 ± 0.3

3.9 ± 0.1

3.4 ± 0.1.

2. The titanosilicate according to claim 1, wherein the bulk density is 0.08 g/ml to 0.11 g/ml.

3. A process for producing a titanosilicate, comprising a first step of heating a mixture containing a

structure-directing agent, a compound containing an element belonging to Group 13 of the periodic table, a

titanium-containing compound, a silicon-containing compound and water under a temperature condition of lower than 155°C to obtain a solid; and a second step of bringing at least one selected from the group consisting of inorganic acids and titanium-containing compounds into contact with the solid obtained in the first step.

4. The process for producing a titanosilicate according to claim 3, wherein the compound containing an element belonging to Group 13 of the periodic table is a boron-containing compound.

5. The process for producing a titanosilicate according to claim 3 or 4, wherein the structure-directing agent is piperidine or hexamethyleneimine .

6. The process for producing a titanosilicate according to any one of claims 3 to 5, further comprising a third step in which the titanosilicate obtained in the second step is heated at a temperature in the range of 250°C to 1000°C.

7. The process for producing a titanosilicate according to any one of claims 3 to 6, further comprising a fourth step in which the titanosilicate obtained in the second step or the third step is brought into contact with the structure-directing agent .

8. The process for producing a titanosilicate according to any one of claims 3 to 7, further comprising a fifth step in which the titanosilicate obtained in the second step, the third step or the fourth step is silylated with a silylating agent.

9. The process for producing a titanosilicate according to any one of claims 3 to 8, further comprising a sixth step in which the titanosilicate obtained in the second step, the third step, the fourth step or the fifth step is brought into contact with hydrogen peroxide.

10. A titanosilicate obtained by the process according to any one of claims 3 to 9.

11. A catalyst for producing an olefin oxide comprising the titanosilicate according to claim 1, 2 or 10.

12. A process for producing an olefin oxide, comprising a step of oxidizing an olefin compound with an oxidizing agent in the presence of the catalyst according to claim 11.

13. The process for producing an olefin oxide according to claim 12, wherein the olefin compound is propylene, and wherein the oxidizing agent is hydrogen peroxide.