JP5126731B2 - Gold catalyst for partial hydrocarbon oxidation - Google Patents

Description

  The present invention relates to a catalyst for partial hydrocarbon oxidation. The present invention also relates to a method for producing an oxygen-containing organic compound using the catalyst, and a method for regenerating the catalyst.

  The process of converting hydrocarbons into oxygenated organic compounds using oxygen is an extremely valuable technology and has provided many benefits to the modern chemical industry. However, it is generally difficult to obtain useful compounds, alcohols and ketones, directly from saturated hydrocarbons and epoxides from unsaturated hydrocarbons, with some exceptions. For example, in the technique of converting saturated hydrocarbons to alcohols and ketones using molecular oxygen as an oxidizing agent, the production of cyclohexanol and cyclohexanone using cyclohexane as a raw material is only carried out industrially. Also, regarding the conversion of unsaturated hydrocarbons to epoxides, ethylene oxide and ethylene oxide and butadiene monooxide are produced industrially from butadiene, but the production of epoxides from other unsaturated hydrocarbons, For example, the synthesis of propylene oxide in one step from propylene is considered to be very difficult.

  So far, as a catalyst that can convert hydrocarbons into oxygen-containing organic compounds such as epoxides, alcohols, and ketones in a single step, gold-titanium oxide (see Patent Document 1) or titanium in which gold fine particles are immobilized. Containing silicate (see Patent Document 2) has been reported. By synthesizing an oxygen-containing organic compound in the presence of hydrogen using these catalysts, (i) the selectivity of the synthesis of the oxygen compound is increased, and (ii) no by-products other than water are produced. Advantages such as easy purification of the target oxygen-containing organic compound and low environmental burden are obtained. In particular, the latter catalyst is superior to the former catalyst in that the conversion rate can be stably maintained for a long period of time.

However, if these catalysts are put into practical use for industrial production, further improvement is desired in terms of reaction efficiency, particularly hydrocarbon conversion rate and hydrogen utilization efficiency. In addition, it is desired that an effective regeneration method for recovering the activity of an industrially used catalyst when the catalyst activity is reduced is established.
JP-A-8-127550 Japanese Patent Laid-Open No. 11-76820

  Therefore, an object of the present invention is to provide a catalyst that can synthesize an oxygen-containing organic compound at a high conversion rate, and that has a high selectivity of the oxygen-containing organic compound and high utilization efficiency of hydrogen.

  In addition, in the present invention, in the oxidation reaction of hydrocarbons in the presence of oxygen and hydrogen, in addition to a high conversion rate, the selectivity of the oxygen-containing organic compound is high, and the oxygen-containing organic compound is used with good hydrogen utilization efficiency. It aims at providing the method which can be synthesize | combined.

  Furthermore, an object of the present invention is to provide an efficient method for regenerating the catalyst.

  The present inventors have intensively studied to solve the above-mentioned problems. As a result, a catalyst in which gold nanoparticles are solidified in a titanium-containing silicate having a pore diameter of 4 nm or more, and a titanium-containing silicate in which gold nanoparticles are immobilized are converted into silane. The catalyst obtained by modifying with a coupling agent is excellent in the selectivity of oxygen-containing organic compounds in the reaction of partially oxidizing hydrocarbons in the presence of oxygen and hydrogen, and the conversion rate of oxygen-containing organic compounds and It has been found that the utilization efficiency of hydrogen is high. Also, by using the above catalyst to partially oxidize hydrocarbons in the presence of oxygen and hydrogen, in addition to high conversion rate, high selectivity and good hydrogen utilization efficiency, epoxide, alcohol, ketone It has been found that oxygen-containing organic compounds such as can be obtained. Moreover, when the catalyst activity decreased by use of the catalyst, it was found that the catalyst activity can be effectively recovered by treating with a mixed gas containing oxygen, hydrogen and argon gas. The present invention has been completed based on such findings and further studies.

That is, the present invention is a hydrocarbon partial oxidation catalyst listed below:
Item 1. A catalyst for partial oxidation of hydrocarbon in which gold nanoparticles are immobilized on a porous body of titanium-containing silicate having an average pore diameter of 4 nm or more.
Item 2. Item 2. The hydrocarbon partial oxidation catalyst according to Item 1, wherein the pore structure of the titanium-containing silicate is a sponge-like structure.
Item 3. Item 2. The hydrocarbon partial oxidation catalyst according to Item 1, wherein the porous body of the titanium-containing silicate has an average pore size of 4 to 50 nm.
Item 4. Item 2. The hydrocarbon partial oxidation catalyst according to Item 1, wherein an atomic ratio (Ti / Si) of Ti and Si in the titanium-containing silicate is 1/10000 to 20/100.
Item 5. A catalyst for partial oxidation of hydrocarbon, in which a titanium-containing silicate on which gold nanoparticles are immobilized is modified with a silane coupling agent.
Item 6. Item 6. The hydrocarbon partial oxidation catalyst according to Item 5, further comprising at least one compound selected from the group consisting of alkali metal compounds and alkaline earth metal compounds.
Item 7. Item 7. The hydrocarbon partial oxidation catalyst according to Item 6, wherein at least one compound selected from the group consisting of barium nitrate, magnesium nitrate and calcium nitrate is supported.
Item 8. Item 6. The hydrocarbon partial oxidation catalyst according to Item 5, wherein the porous body of the titanium-containing silicate has an average pore diameter of 4 to 50 nm.
Item 9. Item 6. The hydrocarbon partial oxidation catalyst according to Item 5, wherein the atomic ratio of Ti to Si (Ti / Si) in the titanium-containing silicate is 1/10000 to 20/100.
Item 10. The silane coupling agent is selected from the group consisting of methoxytrimethylsilane, methoxytriethylsilane, methoxytriisopropylsilane, ethoxytrimethylsilane, ethoxytriethylsilane, ethoxytriisopropylsilane, trimethylsilyl trifluoromethanesulfonate and triethylsilyltrifluoromethanesulfonate. Item 6. The hydrocarbon partial oxidation catalyst according to Item 5, which is at least one kind.
Item 11. At least one compound selected from the group consisting of an alkali metal compound and an alkaline earth metal compound is used in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the titanium-containing silicate to which the gold nanoparticles are immobilized. Item 7. The hydrocarbon partial oxidation catalyst according to Item 6, which is supported at a ratio.

Moreover, this invention is a manufacturing method of the oxygen containing organic compound hung up below.
Item 12. Item 12. A method for producing an oxygen-containing organic compound, comprising oxidizing a hydrocarbon in the presence of hydrogen and oxygen using the hydrocarbon partial oxidation catalyst according to any one of Items 1 to 11.
Item 13. Item 13. The method according to Item 12, which is a method for producing an epoxide by partially oxidizing an unsaturated hydrocarbon.
Item 14. Item 13. The production method according to Item 12, wherein the hydrocarbon is a saturated hydrocarbon having 3 to 12 carbon atoms or an unsaturated hydrocarbon having 2 to 12 carbon atoms.
Item 15. Item 13. The method according to Item 12, wherein the hydrocarbon is oxidized under a temperature condition of 0 to 300 ° C.

Furthermore, the present invention is a method for regenerating a hydrocarbon partial oxidation catalyst described below:
Item 16. Item 12. The method for regenerating a hydrocarbon partial oxidation catalyst according to any one of Items 1 to 11, wherein the hydrocarbon partial oxidation catalyst is treated using a mixed gas containing oxygen and hydrogen. , Regeneration method for hydrocarbon partial oxidation catalyst.
Item 17. Item 17. The regeneration method according to Item 16, wherein the treatment with the mixed gas is performed at 100 to 400 ° C.

FIG. 1 is a diagram showing a structure (hexagonal structure) in which pores having a one-dimensional channel structure are arranged in a hexagonal structure, which is an example of a pore structure of titanium-containing silicate. FIG. 2 is a diagram showing a structure (irregular structure) in which pores having a one-dimensional channel structure are irregularly assembled, which is an example of a pore structure of titanium-containing silicate. FIG. 3 is a view showing a structure (cubic structure) in which pores having a one-dimensional channel structure are three-dimensionally connected, which is an example of a pore structure of titanium-containing silicate. FIG. 4 is a view showing a sponge-like structure (sponge-like structure) in which the pores are irregularly connected three-dimensionally as an example of the pore structure of titanium-containing silicate (transmission electron micrograph) It is.

  In the present invention, the “oxygen-containing organic compound” means an organic compound obtained by partial oxidation of a hydrocarbon, specifically an alcohol, a ketone, an epoxide, or the like. “Hydrocarbon conversion” refers to the proportion (molar ratio) (%) of hydrocarbons consumed by the reaction among the hydrocarbons used as raw materials. The “selectivity of the oxygen-containing organic compound” indicates the ratio (molar ratio) (%) of the hydrocarbons consumed by the reaction converted to the oxygen-containing organic compound. “Yield of oxygen-containing organic compound” refers to the ratio (molar ratio) (%) of the produced oxygen-containing organic compound to the hydrocarbon as a raw material. “Hydrogen conversion rate” indicates the ratio (molar ratio) (%) of hydrogen consumed by the reaction in the hydrogen used for the reaction. The present invention is described in detail below.

(1) Hydrocarbon partial oxidation catalyst (1-1) The hydrocarbon partial oxidation catalyst of the present invention is such that gold nanoparticles are immobilized on a porous body of titanium-containing silicate having an average pore diameter of 4 nm or more. It is a feature. Hereinafter, the hydrocarbon partial oxidation catalyst will be described in detail.

  In the present invention, the gold nanoparticle is a gold fine particle having an average particle diameter of 10 nm or less.

  In the catalyst of the present invention, the gold nanoparticles preferably have an average particle diameter in the range of 2 to 5 nm. It is desirable that such gold nanoparticles are firmly fixed and supported on a titanium-containing silicate carrier. When the particle size of gold is remarkably larger than 10 nm, the specific surface area becomes too small and the conversion rate of hydrocarbon tends to be low. On the other hand, when it becomes remarkably smaller than 2 nm, the property of gold as a metal is lost, the hydrogenation reaction of the unsaturated hydrocarbon proceeds preferentially, and there is a tendency that the partial oxidation reaction does not proceed.

  The content ratio of the gold nanoparticles in the catalyst of the present invention is preferably 0.001 part by weight or more, more preferably in the range of 0.01 to 20 parts by weight, with respect to 100 parts by weight of the titanium-containing silicate, 0.05 More preferably within the range of -10 parts by weight. If the supported proportion of gold nanoparticles is significantly less than 0.001 part by weight, the activity of the catalyst is lowered, which is not preferable. On the other hand, even if the gold loading ratio is more than 20 parts by weight, there is no difference in the activity of the catalyst compared to the case where gold is loaded within the above range.

For the catalyst of the present invention, a porous body of titanium-containing silicate having an average pore diameter of 4 nm or more is used. The porous body of titanium-containing silicate is preferably 5 nm or more, more preferably 7 nm or more.
By using a titanium-containing silicate having an average pore diameter within the above range, the conversion rate of the oxygen-containing organic compound can be improved. The upper limit of the average pore diameter of the titanium-containing silicate porous body is not particularly limited, but is usually 50 nm, preferably 30 nm. As an example of the average pore diameter of the porous body of the titanium-containing silicate, a range of 4 to 50 nm, preferably 4 to 30 nm, and more preferably 7 to 30 nm can be exemplified. In the present invention, the average pore diameter is a value measured by a nitrogen adsorption method.

  The porous body of titanium-containing silicate is a porous body of silicate containing titanium atoms as constituent components. In the porous body of the titanium-containing silicate, it is desirable that the titanium atoms are isolated and dispersed in the silicate.

  The kind of titanium-containing silicate is not particularly limited. Examples include those in which a part of aluminum in the zeolitic material is replaced with titanium and titanium is incorporated in the zeolite lattice, part of silica is replaced with titanium atoms, and a composite oxide of titanium and silicon. Can do. Further, a material in which a minute amount of titanium oxide is highly dispersed and supported on these titanium-containing silicates can also be used.

  The pore structure of the titanium-containing silicate is not particularly limited. As an example of the pore structure of titanium-containing silicate, a structure in which pores having a one-dimensional channel structure are arranged in a hexagonal structure (hereinafter, this structure is called a hexagonal structure) (see FIG. 1), a one-dimensional channel A structure in which pores having a structure are irregularly assembled (hereinafter, the structure is referred to as an irregular structure) (see FIG. 2), and a structure in which pores having a one-dimensional channel structure are three-dimensionally connected. (Hereinafter, this structure is referred to as a cubic structure) (see FIG. 3), and a sponge-like structure in which pores are irregularly connected three-dimensionally (hereinafter, this structure is referred to as a sponge-like structure) (see FIG. 4). And the like. A sponge-containing titanium-containing silicate is preferred. By using a titanium-containing silicate having a sponge-like structure, an oxygen-containing organic compound can be obtained with a higher conversion rate.

  The shape of the titanium-containing silicate is not particularly limited, and may be in a powder form or may be formed into other various shapes.

  The content of titanium in the titanium-containing silicate is preferably in the range of 1/10000 to 20/100 in terms of the atomic ratio of Ti and Si (hereinafter referred to as “Ti / Si”). More preferably within the range of -10/100. If the titanium content is significantly less than Ti / Si = 1/10000, the catalyst characteristics are the same as when a silica-only support is used, and the hydrocarbon is not selectively oxidized, which is inappropriate. On the other hand, if the titanium content is significantly higher than Ti / Si = 20/100, the catalyst characteristics are the same as those of a carrier on which titanium oxide is supported on silica, and deterioration of the catalyst activity over time cannot be avoided.

  Manufacture of the titanium containing silicate used for this invention can be performed according to a well-known manufacturing method according to the hole diameter, pore structure, etc.

  Specific examples of the method for producing a titanium-containing silicate having a sponge-like structure include, for example, a sol-gel method or an improved method thereof (for example, SA Bagshaw et al., Science, 1995, 269, 1242; and Z. Shang et al. Chem. Eur. J., 2001, Vol. 7, p. 1437). Specific examples of the method for producing a titanium-containing silicate having a pore structure of hexagonal structure, irregular structure, or cubic structure include, for example, a hydrothermal synthesis method (for example, Sakai et al., JP-A-7-300312; K Koyano et al., Stud. Surf. Sci. Catal., 1997, Vol. 105, p. 93).

In order to further improve the activity of the catalyst, the titanium-containing silicate can be used in a state of being immobilized on a preformed support. As the support, metal oxides not containing titanium or materials made of various metals can be used. Specific examples include alumina (aluminum oxide: Al ₂ O ₃ ), silica (silicon dioxide: SiO ₂ ), magnesia (magnesium oxide: MgO), cordierite, zirconium oxide, ceramics composed of these complex oxides, and various metals. And the like, honeycomb carriers made of various metals, pellets of various metals, and the like.

  As the support, those containing at least one of alumina and silica are preferred, and those containing silica are particularly preferred. Here, “containing alumina and silica” includes a case where zeolite (aluminosilicate) or silica alumina is contained.

The crystal structure, shape, size, and the like of the support are not particularly limited, but the specific surface area is preferably 50 m ² / g or more, and more preferably 100 m ² / g or more. When the specific surface area of the support is 50 m ² / g or more, side reactions such as sequential oxidation are further suppressed, hydrocarbons can be partially oxidized efficiently, and catalyst performance is further improved. To do.

  When the titanium-containing silicate is immobilized on a support, the amount of the titanium-containing silicate is preferably about 1 to 20% by weight based on the support. In order to support the titanium-containing silicate on a carrier such as silica or alumina, for example, a sol-gel method using an alkoxide, a kneading method, a coating method, or the like can be applied. It can be dispersed and supported so as to form a shape structure.

  Below, the manufacturing method of the catalyst of this invention is demonstrated.

  The method for producing the catalyst of the present invention is not particularly limited as long as the gold nanoparticles can be immobilized on the titanium-containing silicate.

  Specific examples of the method for producing the catalyst include, for example, the precipitation method described in JP-A-7-8797, the vapor deposition method described in JP-A-9-122478, and the impregnation method. There is no particular limitation. The procedure for immobilizing the gold nanoparticles on the titanium-containing silicate by the precipitation method will be described below.

  First, an aqueous solution containing a gold compound is prepared, heated in the range of 30 to 100 ° C., more preferably in the range of 50 to 95 ° C., and the pH of the aqueous solution is adjusted using an aqueous alkaline solution while stirring. It adjusts in the range of 6-12, More preferably, it exists in the range of 7-10. Next, the titanium-containing silicate is added to this aqueous solution at a time or at several times within a few minutes while stirring at the above temperature.

  After introducing the titanium-containing silicate, by continuing stirring at the above temperature for a predetermined time, a solid substance (gold nanoparticle fixed material) formed by adhesion (precipitation precipitation) of gold hydroxide on the surface of the titanium-containing silicate. Is obtained. The solid matter is separated by filtration, washed, and then fired in the air at a temperature of 100 to 800 ° C. Thereby, the gold fine particles are supported on the titanium-containing silicate.

  Specific examples of the alkali component constituting the alkaline aqueous solution include sodium carbonate, potassium carbonate, sodium hydrogen carbonate, sodium hydroxide, potassium hydroxide, cesium hydroxide, ammonia, tetramethylammonium and the like. .

Specific examples of the gold compound include chloroauric acid (HAuCl ₄ ), sodium chloroaurate (NaAuCl ₄ ), gold cyanide (AuCN), and potassium cyanide {K [Au (CN) ₂ ]}. Water-soluble gold salts such as diethylamine trichloride gold acid [(C ₂ H ₅ ) ₂ NH · AuCl ₃ ] are exemplified, but are not limited thereto.

  The concentration of gold in the gold compound-containing aqueous solution used at the time of dropping is not particularly limited, but it is appropriate that gold is usually contained in an amount of about 0.1 to 0.001 mol / l.

  The amount of titanium-containing silicate added to water is not particularly limited. For example, when powdered titanium-containing silicate is used, it may be an amount that can be uniformly dispersed or suspended in water. Usually, about 10 to 200 g / l is appropriate. Moreover, when using a titanium containing silicate as a molded object, according to the shape of a molded object, if an aqueous solution can fully contact the surface, the addition amount will not be specifically limited.

  The catalyst of the present invention can also be produced by a method according to the method for producing an ultrafine gold particle-immobilized substance using an organic gold complex vapor described in JP-A-9-122478. Hereinafter, this method will be briefly described.

  In this method, after vaporized organic gold complex is adsorbed to titanium-containing silicate under reduced pressure, titanium-containing silicate in which gold nanoparticles are immobilized can be obtained by heating to 100 to 700 ° C.

The organic gold complex is not particularly limited as long as it has volatility. For example, (CH ₃ ) ₂ Au (CH ₃ COCHCOCH ₃ ), (CH ₃ ) ₂ Au (CF ₃ COCHCOCH ₃ ), (CH ₃ ) ₂ Au (CF ₃ COCHCOCF ₃ ), (C ₂ H ₅ ) ₂ Au (CH ₃ COCHCOCH ₃ ), (CH ₃ ) ₂ Au (C ₆ H ₅ OOCHCOCF ₃ ), CH ₃ C ₂ AuP (CH ₃ ) ₃ and At least one kind such as CH ₃ AuP (CH ₃ ) ₃ can be used.

  In addition, the titanium-containing silicate can be used after heat treatment at about 200 ° C. in advance to remove moisture on the surface.

The organic gold complex can be vaporized by heating. The heating temperature is not particularly limited as long as it does not cause rapid vaporization and adsorption or decomposition, and is usually about 0 to 90 ° C. The vaporization can also be performed under reduced pressure. In this case, the pressure is usually about 1 × 10 ⁻⁴ to 2 × 10 ⁻³ Torr.

The vaporized organic gold complex is adsorbed on the titanium-containing silicate under reduced pressure. The term “under reduced pressure” in the present invention means a pressure of about 1 × 10 ^{−4 to} 200 Torr, although it may be lower than atmospheric pressure. The amount of the organic gold complex to be introduced varies depending on the type of the gold complex to be used, and may be appropriately adjusted so that the final immobilized amount is obtained. The pressure may be adjusted with a known vacuum pump or the like.

  Next, the titanium-containing silicate adsorbed with the organic gold complex is heated in air usually at about 100 to 700 ° C, preferably at 300 to 500 ° C. As a result, the organic component in the organic gold complex is decomposed and oxidized, and the organic gold complex is reduced to gold and deposited and fixed as gold nanoparticles on the titanium-containing silicate. The heating time can be appropriately set according to the amount of the organic gold complex supported, the heating temperature, etc., but it is usually about 1 to 24 hours. In this way, a titanium-containing silicate having gold nanoparticles immobilized thereon is obtained.

  In the said manufacturing method, prior to adsorption | suction of an organic gold complex, it can also surface-treat a titanium containing silicate by heating at about 100-700 degreeC normally. Furthermore, this surface treatment can also be performed in an oxidizing gas or reducing gas atmosphere. Thereby, the amount of defects and the state of the titanium-containing silicate surface can be controlled more easily, and the gold particle size and the amount supported can be controlled more finely.

  As the oxidizing gas, known ones can be used, and examples thereof include oxygen gas and nitrogen monoxide gas. Moreover, as said reducing gas, a well-known thing can be used, for example, hydrogen gas, carbon monoxide gas, etc. are mentioned.

  According to the method for depositing and precipitating gold and the method using the vapor of the organic gold complex described above, the gold nanoparticles can be firmly fixed on the titanium-containing silicate with a relatively uniform distribution.

When the catalyst of the present invention is supported on a support and used, a method of immobilizing gold after the titanium-containing silicate is supported on the support is preferable. In order to immobilize gold on the titanium-containing silicate supported on the support, in the method of depositing and precipitating gold and the method using the vapor of the organic gold complex, the titanium-containing silicate is used instead of the titanium-containing silicate. A support carrying a salt may be used. In particular, when produced by a method of depositing and precipitating gold, the gold nanoparticles are hardly deposited on the support and are immobilized only on the titanium-containing silicate (particularly where titanium ions are present). Is advantageous. Also, when using a support of silica alone or a support containing silica, according to the method of depositing and precipitating gold, it is possible to immobilize gold nanoparticles only on a titanium-containing silicate with particularly high selectivity. This is very advantageous.

  (1-2) Moreover, this invention provides the catalyst for partial oxidation of hydrocarbon characterized by the titanium containing silicate which fix | immobilized the gold nanoparticle was modified with the silane coupling agent. Hereinafter, the catalyst will be described in detail.

  The gold nanoparticles that can be used in the catalyst of the present invention are the same as those that can be used in the above (1-1). The blending ratio of the gold nanoparticles to the titanium-containing silicate is the same as the blending ratio of the gold nanoparticles to the titanium-containing silicate described in (1-1).

  The type of titanium-containing silicate used in the catalyst of the present invention is not particularly limited. For example, a part of aluminum in the zeolitic material is replaced with titanium and titanium is incorporated in the zeolite lattice, silica And those in which a part of is substituted with a titanium atom, a composite oxide of titanium and silicon, and the like. In addition, it is also possible to use a fine dispersion of a small amount of titanium oxide supported on these titanium-containing silicates.

  The form of the titanium-containing silicate is not particularly limited, but is preferably a porous body having an average pore diameter of 4 nm or more. From the viewpoint of improving the conversion rate of the oxygen-containing organic compound, the porous body is more preferably 5 nm or more, more preferably 7 nm or more. The upper limit of the average pore diameter of the titanium-containing silicate porous body is not particularly limited, but is usually 50 nm, preferably 30 nm. As an example of the average pore diameter of the porous body of the titanium-containing silicate, a range of 4 to 50 nm, preferably 4 to 30 nm, and more preferably 7 to 30 nm can be exemplified.

  Moreover, when using the porous body of a titanium containing silicate, the pore structure is not specifically limited. Examples of the pore structure of the titanium-containing silicate include a hexagonal structure, an irregular structure, a cubic structure, and a sponge-like structure. Of these, a sponge-like structure is preferable.

  The titanium content in the titanium-containing silicate is the same as the titanium content in the titanium-containing silicate used in (1-1) described above.

  The titanium-containing silicate used in the present invention can be produced according to a known production method.

  Moreover, the said titanium containing silicate can also be used in the state fix | immobilized to the support body shape | molded previously, in order to improve the activity of a catalyst similarly to (1-1) mentioned above. The support is the same as that used in (1-1) described above.

  Although it does not restrict | limit especially as a method of fix | immobilizing a gold nanoparticle to a titanium containing silicate, For example, the precipitation method described in (1-1) mentioned above can be mentioned.

  The catalyst of the present invention is obtained by modifying the surface of a gold nanoparticle-immobilized titanium-containing silicate obtained as described above with a silane coupling agent.

  As the silane coupling agent for modifying the gold nanoparticle-immobilized titanium-containing silicate, a conventionally known silane coupling agent can be used without limitation. Preferred silane coupling agents include, for example, methoxytrimethylsilane, methoxytriethylsilane, methoxytriisopropylsilane, ethoxytrimethylsilane, ethoxytriethylsilane, ethoxytriisopropylsilane, trimethylsilyl trifluoromethanesulfonate, triethylsilyltrifluoromethanesulfonate, and the like. Can be mentioned. Among these, by using methoxytrimethylsilane or methoxytriethylsilane in particular, it becomes possible to synthesize an oxygen-containing organic compound with an even higher conversion rate. These silane coupling agents may be used alone or in any combination of two or more.

  The modification with the titanium coupling agent is performed by reacting a hydroxyl group on the surface of the gold nanoparticle-immobilized titanium-containing silicate with a silane coupling agent.

  As a method of modifying the titanium-containing silicate on which the gold nanoparticles are immobilized with a silane coupling agent, a conventionally known surface treatment method using a silane coupling agent can be employed. For example, an inert gas such as argon gas is passed through the silane coupling agent to vaporize the silane coupling agent, and then the vapor containing the silane coupling agent is brought into contact with the silicate containing the titanium nanoparticles immobilized on gold nanoparticles. Then, the method of processing for about 5 to 60 minutes at about 50-200 degreeC in the said inert gas atmosphere can be mentioned. In addition, as other methods, for example, a method in which a gold nanoparticle-immobilized titanium-containing silicate is slurried or immersed in a dilute solution of a silane coupling agent (wet method), or a gold fine particle-immobilized titanium-containing silicate is accelerated. Examples thereof include a method (dry method) of uniformly dispersing a stock solution or solution of a silane coupling agent while stirring.

  Furthermore, at least one compound selected from the group consisting of an alkali metal compound and an alkaline earth metal compound (hereinafter sometimes referred to as “alkali compound”) is immobilized on the titanium-containing silicate (supported) It is possible to further improve the conversion rate of the oxygen-containing organic compound.

  Here, examples of the alkali metal include sodium, potassium, cesium and the like, and examples of the alkali metal compound include nitrates, sulfates, carbonates, bicarbonates, hydroxide salts, oxalates of these alkali metals, Examples include various salts such as acetate.

  Examples of the alkaline earth metal include calcium, magnesium, strontium, barium, and beryllium. Examples of the alkaline earth metal compound include nitrates, sulfates, carbonates, hydrogen carbonates of these alkaline earth metals, Various salts such as hydroxide salt, oxalate salt, acetate salt and the like can be mentioned.

  Among these alkali metal compounds and alkaline earth metal compounds, preferred are salts of cesium, barium, magnesium, calcium and the like, and more preferred are salts of barium, magnesium and the like. In particular, among these alkali metal compounds and alkaline earth metal compounds, specific examples of preferable compounds include barium nitrate, magnesium nitrate, and calcium nitrate, and more preferable examples include barium nitrate and magnesium nitrate. These alkali metal compounds and alkaline earth metal compounds may be used alone or in any combination of two or more.

  The ratio between the titanium-containing silicate and the alkali compound varies depending on the type of titanium-containing silicate used, the type of alkali metal, etc., and cannot be uniformly defined. For example, gold nanoparticle-immobilized titanium-containing silicate 100 The total amount of the alkali compound relative to parts by weight is usually 0.001 to 10 parts by weight, preferably 0.001 to 1 part by weight, and more preferably 0.001 to 0.2 parts by weight.

  A method for immobilizing the alkali compound on the titanium-containing silicate is not particularly limited. For example, in accordance with the method for fixing gold nanoparticles to titanium-containing silicate by the precipitation method described in (1-1) described above, the alkali compound is fixed by using an alkali compound instead of the gold compound. Can be made. More specifically, in the method for immobilizing gold nanoparticles by the precipitation method described in (1-1) above, 0.001 to 10 mmol / l, preferably 0. The alkaline compound can be immobilized by dropping an aqueous solution of the alkaline compound of 001 to 0.2 mmol / l in an amount corresponding to the amount of the alkaline compound supported on the titanium-containing silicate.

The alkali compound may be fixed to the titanium-containing silicate after the gold fine particles are fixed to the titanium-containing silicate, or may be performed before the gold fine particles are fixed to the titanium-containing silicate. Further, the fixation of the gold nanoparticles and the alkali compound to the titanium-containing silicate can be performed simultaneously. Preferably, the method is performed simultaneously. In order to simultaneously immobilize the gold fine particles and the alkaline earth metal, for example, in the method for immobilizing gold nanoparticles to titanium-containing silicate by the precipitation method described in (1) above, a predetermined amount together with the gold compound It can implement by using the aqueous solution containing the alkali compound of.

(2) Method for Producing Oxygenated Organic Compound Hereinafter, a method for producing an oxygenated organic compound by partially oxidizing hydrocarbons using the catalyst of the present invention will be described.

  In the present production method, as the hydrocarbon which is a raw material compound, a saturated hydrocarbon having about 3 to 12 carbon atoms or an unsaturated hydrocarbon having about 2 to 12 carbon atoms can be used. When the reaction is carried out in the gas phase, those having up to about 6 carbon atoms that can be easily desorbed from the catalyst layer even at a low temperature of around 100 ° C. are suitable as raw materials. Examples of the saturated hydrocarbon include propane, n-butane, isobutane, cyclobutane, n-pentane, 2-methylbutane, cyclopentane, n-hexane, 2-methylpentane, 3-methylpentane, cyclohexane and the like. As unsaturated hydrocarbons, compounds having a double bond, such as ethylene, propylene, 1-butene, 2-butene, isobutene, 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl- 1-butene, cyclopentene, 1-hexene, 2-hexene, 3-hexene, 2-methyl-1-pentene, 3-methyl-1-pentene, cyclohexene, 1-methyl-1-cyclopentene, 3-methyl-1- Examples include cyclpentene and 4-methyl-1-pentene.

  When an unsaturated hydrocarbon is used as a raw material compound, an epoxide is generated with high selectivity.

  When a saturated hydrocarbon is used as a raw material compound, a ketone is mainly produced when the secondary carbon-hydrogen bond is oxidized, and an alcohol is mainly produced when the tertiary carbon-hydrogen bond is oxidized. Is generated. The order of reactivity of carbon-hydrogen bonds is tertiary> secondary> primary, and primary carbon-hydrogen bonds hardly react.

The catalyst used in the method of the present invention is the catalyst described in (1) above. The amount of the catalyst to be used is not particularly limited, but it is practically suitable that the space velocity (SV) is in the range of about 100 to 10,000 hr ⁻¹ · ml / g · cat. Yes.

  In the present invention, the presence of hydrogen is essential. If hydrogen does not coexist, that is, even if a mixed gas consisting of oxygen, hydrocarbons, and possibly diluting gas is reacted in the presence of the catalyst, the reaction begins to occur at 200 ° C. or higher, but carbon dioxide is produced. Is mainly recognized, and the generation of the oxygen-containing organic compound is not recognized at all. However, when hydrogen is present in the reaction system, the reaction mode is completely changed, and the generation of the oxygen-containing organic compound is observed even at a low temperature of about 50 ° C. Although the amount of hydrogen is not particularly limited, it can be practically used within a range of about 1/10 to 100/1 in terms of the volume ratio of hydrogen / raw material. Since the speed increases, it is preferable to adopt a higher value within this range.

  The amount of oxygen present is not particularly limited, but is usually in the range of about 1/10 to 10/1 in terms of oxygen / raw material volume ratio. If the amount of oxygen present is less than this range, the amount of the partially oxidized product obtained is not preferable, and on the other hand, even if the amount of oxygen present is greater than this range, the amount of oxygen-containing organic compound obtained is not enough. This is not preferable because it does not increase, but rather decreases the selectivity of the oxygen-containing organic compound (increases the amount of carbon dioxide produced).

  The reaction temperature in the present invention is usually in the range of about 0 to 300 ° C, more preferably about 50 to 200 ° C. When the reaction is carried out in the gas phase, the product is sufficiently volatile under the reaction pressure employed (usually about 0.01 to 1 MPa) so that the product can be easily desorbed from the catalyst layer. It is necessary to select the temperature shown. On the other hand, if the reaction temperature is too high, combustion reaction to carbon dioxide tends to occur, and at the same time, consumption due to oxidation of hydrogen to water increases, which is not preferable. Therefore, although there is an optimum reaction temperature depending on the difference in the raw materials used, a suitable reaction temperature seems to fall within the range of about 50 to 200 ° C.

  In the gas phase reaction, a mixed gas containing hydrocarbon, hydrogen, oxygen and, if necessary, a diluent gas (for example, nitrogen, argon, helium, carbon dioxide, etc.) is supplied to a reactor filled with the catalyst of the present invention, and a predetermined reaction What is necessary is just to make it react on condition.

When the reaction in the present invention is carried out in the liquid phase, it is not necessary to consider the above desorption from the catalyst layer, and in many cases, it can be carried out at 100 ° C. or lower. When the reaction is performed in the liquid phase, a reaction pressure and a reaction temperature that keep the raw material in a liquid state are selected, or a solvent (for example, a hydrocarbon solvent such as benzene, halogenation such as methylene chloride) is selected. The reaction can be carried out by bubbling a mixed gas of a raw material compound, hydrogen, oxygen, and possibly a diluent gas in the presence of a suspended catalyst using a hydrocarbon solvent or the like.

(3) Regeneration method for the catalyst for partial oxidation of hydrocarbon When the catalyst for partial oxidation of hydrocarbon is reduced in its catalytic activity, the catalyst for partial oxidation of hydrocarbon is used by using a mixed gas containing oxygen and hydrogen. By treating this, the hydrocarbon partial oxidation catalyst can be regenerated.

  In the above mixed gas, the ratio of oxygen and hydrogen is not particularly limited. As an example, oxygen: hydrogen is in a volume ratio of 0.1: 99.9 to 99.9: 0.1, preferably A ratio of 10:90 to 90:10, more preferably 25:75 to 75:25 is mentioned.

  Further, it is desirable that the mixed gas contains a diluent gas (for example, nitrogen, argon, helium, carbon dioxide, etc.) in addition to the oxygen and hydrogen. When the diluent gas is included in the mixed gas, for example, the diluent gas is usually 1 to 999 parts by volume, preferably 1 to 99 parts by volume, more preferably 1 to 9 parts by volume with respect to 1 part by volume of oxygen and hydrogen. The ratio which becomes a part can be mentioned.

  As temperature conditions at the time of processing the hydrocarbon partial oxidation catalyst with the above mixed gas, for example, 0 to 500 ° C., preferably 50 to 400 ° C., more preferably 100 to 300 ° C., particularly preferably about 250 ° C. be able to. If it is within the said temperature range, a catalyst reproduction | regeneration can be performed efficiently.

  The method for treating the hydrocarbon partial oxidation catalyst with the mixed gas is not particularly limited as long as the hydrocarbon partial oxidation catalyst to be regenerated is brought into contact with the mixed gas. For example, the hydrocarbon partial oxidation catalyst may be treated as follows. Examples thereof include a method of continuously supplying and extracting the mixed gas to and from a filled container, and a method of sealing the container by adding the mixed gas to the container. For example, a method of supplying the mixed gas instead of the reactive gas in the reactor used for partial oxidation of hydrocarbon can be exemplified.

  The ratio of the mixed gas brought into contact with the hydrocarbon partial oxidation catalyst varies depending on the component ratio of the mixed gas used, the degree of loss of activity of the hydrocarbon partial oxidation catalyst, etc., and cannot be defined uniformly. However, for example, the total amount of the mixed gas is 0.1 to 100 L, preferably 1 to 50 L, and more preferably 5 to 25 L with respect to 1 g of the hydrocarbon partial oxidation catalyst.

Hereinafter, the present invention will be described in more detail with reference to examples. However, the present invention is not limited to these examples.
Example 1
1. Preparation of titanium- containing silicate 0.7 g of titanium butoxide solution (Ti = 6 mol%) was added dropwise to 20.8 g of tetraethylorthosilicate. Next, 29.8 g of triethanolamine was added dropwise thereto and mixed, and then 19.8 g of deionized water was added thereto. After stirring the resulting solution for 2 hours, 14.7 g of tetraethylammonium hydroxide was added dropwise. The liquid mixture thus obtained was allowed to stand at room temperature for 24 hours, dried at 100 ° C. for 12 hours, and then calcined in air at 700 ° C. for 10 hours. The titanium-containing silicate thus obtained has a Ti / Si atomic ratio of titanium-containing silicate of 3/100 and has a sponge-like structure with an average pore diameter of 7.4 nm. By ICP elemental analysis, the latter was confirmed by powder X-ray diffraction (XRD), nitrogen adsorption (BET), and TEM (transmission electron microscope) analysis.

2. Dissolve 1.0 g (2.43 mmol) of chloroauric acid tetrahydrate (HAuCl ₄ .4H ₂ O) in 1200 ml of immobilized distilled water of gold nanoparticles, warm to 70 ° C., and add 0.1N NaOH aqueous solution. After the pH was adjusted to 7.5, 6 g of the titanium-containing silicate obtained above was added all at once with vigorous stirring, and stirring was continued for 1 hour at the same temperature. On the titanium-containing silicate, gold hydroxide Au ( OH) ₃ was precipitated out. The suspension was allowed to stand and allowed to cool to room temperature. Then, the supernatant was removed, 3000 ml of distilled water was newly added, stirred at room temperature for 5 minutes, and allowed to stand again to remove the supernatant. This washing operation is repeated several times, followed by filtration. The resulting paste is vacuum-dried at room temperature for 12 hours and calcined in air at 400 ° C. for 4 hours, whereby a titanium-containing silicate catalyst carrying ultrafine gold particles Got. The amount of chloroauric acid used was 8% by weight based on the titanium-containing silicate (TiO-SiO), but as a result of analysis, the amount of gold actually carried was 0.42% by weight. .

3. Propylene Partial Oxidation Reaction Using the catalyst obtained above, propylene partial oxidation reaction was carried out using a fixed bed flow type catalytic reactor. The reaction conditions are as follows.
Catalytic reaction cell: quartz, inner diameter 10 mm,
Catalyst amount: 0.15 g,
Catalyst pretreatment: After flowing a mixed gas of argon / H ₂ = 9/1 (volume ratio) at 250 ° C. for 30 minutes, a mixed gas of argon / O ₂ = 9/1 (volume ratio) is 30 ° C. at 250 ° C. Distribution,
Reaction gas: volume ratio Argon / O ₂ / H ₂ / Propylene = 7/1/1/1
Space velocity: 4000 h ⁻¹ · ml / g · cat,
Reaction temperature: 150 ° C.

  For comparison, titanium-containing silicates having the pore diameters and pore structures shown in Table 1 below (Comparative Examples 1 to 4), silicate-supported titanium having no pore structure (Comparative Example 5), and pore structure Using fine titanium dioxide (Comparative Example 6) not containing gold, gold fine particles were immobilized in the same manner as described above to carry out a partial oxidation reaction of propylene.

  The results of the partial oxidation reaction of propylene using the catalysts of Example 1 and Comparative Examples 1 to 6 (propylene conversion, propylene oxide selectivity, propylene oxide yield, and hydrogen conversion) are shown in the table below. It is shown in 2.

  From these results, the catalyst (Example 1) in which gold fine particles are supported on a titanium-containing silicate having an average pore size of 7.4 nm is smaller than the comparative examples 1 to 6 having a small pore size or no pore size. Thus, it was confirmed that the conversion rate of propylene was high and the yield of propylene oxide was also high. Further, in Example 1, the propylene oxide selectivity was as good as 90% or more, and the hydrogen conversion was also as good as about 14%.

Example 2-4
1. Catalyst preparation
(i) Examples 2 and 3
In accordance with the method described in Example 1, gold nanoparticles were immobilized on the titanium-containing silicate shown in Table 3. Next, Ar gas was introduced into a container filled with methoxytrimethylsilane at 25 ° C. to generate a vapor containing methoxytrimethylsilane, and the vapor was filled in the reaction tube at a flow rate of 10 ml / min for 30 minutes. The gold nanoparticle-immobilized titanium-containing silicate was treated by passing the gas through 0.15 g of titanium-containing silicate on which fine particles were immobilized, and then flowing Ar gas at a flow rate of 10 ml / min at 200 ° C. for 5 hours. The silylation was performed.
(ii) Example 4
Using a solution prepared by dissolving 0.261 g (0.1 mmol) of Ba (NO ₃ ) ₂ together with 1.0 g (2.43 mmol) of chloroauric acid tetrahydrate (HAuCl ₄ .4H ₂ O) in 1200 ml of distilled water The gold nanoparticles and Ba (NO ₃ ) ₂ were fixed to the titanium-containing silicate by treating the titanium-containing silicate shown in Table 3 under the same conditions as those for fixing the gold fine particles described in Example 1. Turned into. Next, silylation was performed in the same manner as in Example 2-3.
(iii) Comparative Example 7-10
For comparison, the catalyst shown below was prepared: Example 1 using the titanium-containing silicate shown in Table 3 (TiO-SiO; titanium-containing silicate having a sponge-like structure prepared in Example 1). Gold nanoparticles fixed only according to the method described (Comparative Examples 7 and 8); using the titanium-containing silicate shown in Table 3, gold fine particles and Ba (NO (NO)) according to the method described in Example 4 ₃ ) In the method described in Example 4 using only the immobilization of ₂ (Comparative Example 9); and the titanium-containing silicate shown in Table 3, Mg instead of Ba (NO ₃ ) _{2 (NO 3)} the gold particles and Mg _{(NO 3)} those where only ₂ of the immobilized (Comparative example 10) using ₂ hexahydrate 0.256 g (0.1 mmol).

2. Partial oxidation reaction of propylene Using the catalysts thus obtained (Example 2-4 and Comparative Example 7-10), a partial oxidation reaction of propylene was carried out under the same conditions as in Example 1, and 0.5 hours after the start of the reaction. The conversion rate of propylene after 4 hours, the selectivity of propylene oxide, the yield of propylene oxide, and the hydrogen conversion rate were examined (however, in Comparative Example 8-10, measured only 1 hour after the start of the reaction).

  The obtained results are also shown in Table 3.

As a result, in the catalyst (Example 2-4) in which the titanium-containing silicate having the gold fine particles fixed thereto is silylated, propylene oxide is selected at a high propylene conversion rate and high in comparison with Comparative Example 7-10. It was confirmed that it can be obtained at a rate. In particular, it is clear that a higher propylene conversion rate and propylene oxide selectivity can be achieved with a catalyst obtained by silylating a titanium-containing silicate in which Ba (NO ₃ ) ₂ is immobilized together with gold fine particles. It became.

Example 5
The following test was performed using the silylated gold nanoparticle fixed titanium-containing silicate of Example 2 as a catalyst.

Using the above catalyst, a partial oxidation reaction of propylene was carried out for 5 hours using a fixed bed flow type catalytic reactor. The reaction conditions are as follows.
Catalytic reaction cell: quartz, inner diameter 10 mm,
Catalyst amount: 0.15 g,
Catalyst pretreatment: After flowing a mixed gas of argon / H ₂ = 9/1 (volume ratio) at 250 ° C. for 30 minutes, a mixed gas of argon / O ₂ = 9/1 (volume ratio) at 250 ° C. 30 minutes distribution,
Reaction gas: volume ratio Argon / O ₂ / H ₂ / Propylene = 7/1/1/1
Space velocity: 4000 h ⁻¹ · ml / g · cat,
Reaction temperature: 165 ° C.

  The conversion rate of propylene, the selectivity of propylene oxide, the yield of propylene oxide, and the conversion rate of hydrogen were determined in the reaction (the number of regeneration treatments was 0).

Next, after the reaction, the regeneration treatment was performed under the following conditions with the catalyst being filled in the reaction cell.
Catalyst pretreatment: Argon / H ₂ / O ₂ = 8/1/1 mixed gas at 250 ° C. for 30 minutes,
Space velocity: 4000 h ⁻¹ · ml / g · cat,
Processing temperature: 250 ° C
Using this regenerated catalyst (recycled once), a partial oxidation reaction of propylene is performed again under the above reaction conditions, propylene conversion, propylene oxide selectivity, propylene oxide yield, and hydrogen content. Conversion was determined.

  Furthermore, the regeneration and reaction of the catalyst were repeated again under the above conditions (the number of regeneration treatments was twice), and the propylene conversion rate, propylene oxide selectivity, propylene oxide yield, and hydrogen conversion rate were determined.

Table 4 shows the obtained results. As a result, the catalyst whose activity is reduced by use,
It was confirmed that excellent catalytic activity can be recovered again by subjecting it to the treatment of the regeneration method of the present invention.

  According to the hydrocarbon partial oxidation catalyst of the present invention, it is possible to synthesize oxygen-containing organic compounds with high conversion and high selectivity in the reaction of partial oxidation of hydrocarbons in the presence of oxygen and hydrogen. On the other hand, at the same time, wasteful hydrogen consumption (water generation) can be suppressed and an oxygen-containing organic compound can be produced efficiently.

  Therefore, according to the method for partial oxidation of hydrocarbons using the hydrocarbon partial oxidation catalyst of the present invention, oxygen-containing organic compounds such as alcohols, ketones, and epoxides are efficiently produced from hydrocarbons in one step. It becomes possible to do.

  In addition, even if the catalytic activity of the present invention is reduced by using the hydrocarbon partial oxidation catalyst of the present invention, it can be easily regenerated by treatment with a mixed gas containing oxygen, hydrogen and argon gas. It is suitable for.

Claims (11)

A hydrocarbon partial oxidation catalyst having gold nanoparticles immobilized on a porous titanium-containing silicate having an average pore diameter of 4 nm or more, and having the following characteristics (i) to (vi) : catalyst
(i) Titanium-containing silicate with immobilized gold nanoparticles is modified with a silane coupling agent
(ii) The average particle diameter of the gold nanoparticles is 2 to 5 nm.
(iii) The content ratio of the gold nanoparticles is 0.05 to 10 parts by weight with respect to 100 parts by weight of the titanium-containing silicate.
(iv) The average pore diameter of the porous body of the titanium-containing silicate measured by the nitrogen adsorption method is 7 to 30 nm.
(v) The pore structure of the titanium-containing silicate is a sponge-like structure
(vi) The atomic ratio of Ti and Si (Ti / Si) in the titanium-containing silicate is 1/100 to 10/100. The catalyst for partial oxidation of hydrocarbon according to claim 1, further comprising at least one compound selected from the group consisting of an alkali metal compound and an alkaline earth metal compound. The hydrocarbon partial oxidation catalyst according to claim 2, wherein at least one compound selected from the group consisting of barium nitrate, magnesium nitrate and calcium nitrate is supported. Silane coupling agent is at least one selected methoxytrimethylsilane, methoxy triethylsilane, et butoxy trimethylsilane, ethoxyethyl triethylsilane, from preparative trimethyl silyl trifluoromethane sulfonate and the group consisting of triethylsilyl trifluoromethanesulfonate, wherein Item 4. The hydrocarbon partial oxidation catalyst according to any one of Items 1 to 3. At least one compound selected from the group consisting of an alkali metal compound and an alkaline earth metal compound is used in an amount of 0.001 to 10 parts by weight based on 100 parts by weight of the titanium-containing silicate to which the gold nanoparticles are immobilized. The hydrocarbon partial oxidation catalyst according to claim 2 , which is supported at a ratio. A method for producing an oxygen-containing organic compound, comprising oxidizing a hydrocarbon in the presence of hydrogen and oxygen using the hydrocarbon partial oxidation catalyst according to any one of claims 1 to 5. The method according to claim 6, which is a method for producing an epoxide by partially oxidizing an unsaturated hydrocarbon. The production method according to claim 6, wherein the hydrocarbon is a saturated hydrocarbon having 3 to 12 carbon atoms or an unsaturated hydrocarbon having 2 to 12 carbon atoms. The production method according to any one of claims 6 to 8, wherein the hydrocarbon is oxidized under a temperature condition of 0 to 300 ° C. A method for regenerating a hydrocarbon partial oxidation catalyst according to any one of claims 1 to 5, wherein the hydrocarbon partial oxidation catalyst is treated using a mixed gas containing oxygen and hydrogen. A method for regenerating a catalyst for partial oxidation of hydrocarbon. The regeneration method according to claim 10, wherein the treatment with the mixed gas is performed at 100 to 400 ° C.