JPH08269030A - Propylene oxide manufacturing method - Google Patents

Abstract

(57) [Summary] [Objective] To provide a method for producing propylene oxide with high selectivity. In a method for producing propylene oxide by directly oxidizing propylene with oxygen and hydrogen, propylene is directly oxidized with oxygen and hydrogen in the presence of a catalyst in which a noble metal of Group VIII of the periodic table is supported on titanosilicate. In the reaction, the reaction temperature is set to 0 to 40 ° C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a novel process for producing propylene oxide. The propylene oxide obtained in the present invention is a very useful compound as a raw material for propylene glycol, polypropylene glycol and the like.

[0002]

2. Description of the Related Art As a method for producing propylene oxide, a chlorohydrin method in which propylene is passed through chlorohydrin is known. Further, the Halcon method in which propylene is oxidized using t-butyl hydroperoxide or ethylbenzene hydroperoxide as an oxidizing agent and the peracetic acid method in which peracetic acid is used as an oxidizing agent are known.

However, the above-mentioned chlorhydrin method requires two or more steps from propylene, and since chlorhydrin is dehydrochlorinated with lime milk, a large amount of calcium chloride is produced as a by-product, and the treatment of this by-product is a problem. Become.
Further, in the Halcon method and the peracetic acid method, it is necessary to additionally provide a step for producing an oxidant, and since t-butanol, acetic acid and the like are co-produced, it is necessary to secure a market for this co-produced product.

Therefore, in the method for producing propylene oxide, some attempts have been made to obtain propylene oxide from propylene in a single step in a process that does not require treatment of by-products or market securing of co-products. There is.

For example, Japanese Patent Application Laid-Open No. 59-51273 discloses a method of directly oxidizing propylene with hydrogen peroxide using titanosilicate as a catalyst.

Further, Japanese Patent Laid-Open No. 4-3527771 discloses that
A method for producing propylene oxide by directly oxidizing propylene with oxygen and hydrogen using a catalyst composed of a noble metal of Group VIII of the periodic table and titanosilicate is disclosed.

[0007]

However, in the method described in Japanese Patent Laid-Open No. 59-51273, expensive hydrogen peroxide is required in an equimolar amount or more with respect to propylene oxide produced, which is a problem in terms of economy. There is.

The method described in JP-A-4-352771 is excellent in that it does not use expensive hydrogen peroxide, but the selectivity of propylene oxide varies depending on the composition of the raw material gas during the oxidation reaction, and It was not sufficient as an industrial production method, such as variation depending on the preparation conditions of.

The present invention has been made in view of the above problems, and an object thereof is to produce propylene oxide with high selectivity without the above-mentioned problems in the reaction of directly oxidizing propylene with oxygen and hydrogen. Is to provide a way to do.

[0010]

Means for Solving the Problems The inventors of the present invention have earnestly studied a method for producing propylene oxide. as a result,
In a method for producing propylene oxide by directly oxidizing propylene with oxygen and hydrogen in the presence of a catalyst in which a noble metal of Group VIII of the periodic table is supported on titanosilicate, a reaction is performed at a reaction temperature within a specific range. The inventors have found that propylene oxide can be obtained with high selectivity without being affected by gas composition and catalyst preparation conditions, and have completed the present invention.

That is, in the present invention, the reaction temperature is set to 0 to 40 ° C. in the reaction of directly oxidizing propylene with oxygen and hydrogen in the presence of a catalyst in which a noble metal of Group VIII of the periodic table is supported on titanosilicate. It is a method for producing propylene oxide, which is characterized in that

Next, the present invention will be described in more detail.

In the method of the present invention, the periodic table VII
A catalyst in which a noble metal of Group I is supported on titanosilicate is used.

The titanosilicate referred to in the present invention is represented by the following general formula nSiO ₂ · in which a part of silicon forming the crystal lattice of crystalline SiO ₂ (called silicalite) having a zeolite structure is replaced by titanium. (1-n) a synthetic zeolite material represented by TiO _2, the synthetic zeolite material Chitanoshirike shows the X-ray diffraction pattern of pentasil-type structure - means the door. In the general formula, n is usually 0.
8 to 0.999.

The method for synthesizing the titanosilicate used in the present invention is not particularly limited, and a known method,
For example, JP-A-56-96720 and JP-A-60-1
It may be synthesized by the method described in Japanese Patent No. 27217.

According to Japanese Patent Laid-Open No. 56-96720,
Titanosilicate is synthesized by hydrolyzing tetraalkyl orthosilicate and tetraalkyl orthotitanate with an aqueous solution of tetraalkylammonium hydroxide, and then hydrothermally synthesizing the same.

In the present invention, the tetraalkyl orthosilicate is not particularly limited, but for example, tetramethyl orthosilicate, tetraethyl orthosilicate, tetrapropyl orthosilicate, tetrabutyl orthosilicate, tetrapentyl orthosilicate, tetrahexyl orthosilicate. Examples thereof include silicate, tetraheptyl orthosilicate, tetraoctyl orthosilicate, trimethylethyl silicate, dimethyldiethylsilicate, methyltriethylsilicate, dimethyldipropylsilicate and ethyltripropylsilicate. Of these, tetraethyl orthosilicate is preferably used because it is easily available.

In the present invention, tetraethyl orthotitanate is not particularly limited, but examples thereof include tetramethyl orthotitanate, tetraethyl orthotitanate, tetrapropyl orthotitanate, tetrabutyl orthotitanate, tetraoctyl orthotitanate and trimethylethyl titanate. , Dimethyl diethyl titanate, methyl triethyl titanate, dimethyl dipropyl titanate and ethyl tripropyl titanate. Of these, tetraethyl orthotitanate and tetrabutyl orthotitanate are preferably used because they are easily available.

In the present invention, tetraalkylammonium hydroxide is not particularly limited, but examples thereof include tetramethylammonium hydroxide, tetraethylammonium hydroxide, tetrapropylammonium hydroxide, tetrabutylammonium hydroxide and the like. . Of these, tetrapropylammonium hydroxide is preferably used because it is easily available.

In the present invention, the charging ratio of these reaction raw materials when synthesizing the titanosilicate is not particularly limited, but it is preferably as follows. The amount of tetraalkyl orthosilicate used is usually 1 to 100 equivalents, preferably 5 to 35 equivalents, relative to 1 mol of tetraalkyl orthotitanate. The amount of tetraalkylammonium hydroxide used is usually 0.1 to 1 equivalent based on 1 mol of tetraalkyl orthosilicate,
It is preferably 0.2 to 0.6 equivalent. The concentration of the tetraalkylammonium hydroxide aqueous solution is usually 3-5.
It is 0% by weight, preferably 5 to 40% by weight.

In the present invention, the temperature of hydrolysis when synthesizing the titanosilicate is not particularly limited, but is usually -20 to 60 ° C, preferably -10 to 40 ° C. The reaction time is not particularly limited, but is usually 1
It is 0 minutes to 100 hours, preferably 30 minutes to 50 hours. If necessary, a solvent can be used during hydrolysis. The solvent is not particularly limited, but examples thereof include alcohols such as methanol, ethanol, propanol, butanol, and octanol, ketones such as acetone and methyl ethyl ketone, diethyl ether, tetrahydrofuran, ethers such as dimethoxyethane, and the like. You can

In the hydrolysis reaction, if a uniform hydrolysis product can be obtained, the mixing order and mixing method of the reaction raw materials of tetraalkyl orthosilicate, tetraalkyl orthotitanate and tetraalkylammonium hydroxide aqueous solution are particularly limited. is not. For example, all of the above compounds may be mixed at once, or an aqueous solution of alkylammonium hydroxide may be added dropwise to a mixture of tetraalkyl orthosilicate and tetraalkyl orthotitanate. Further, an aqueous solution of alkylammonium hydroxide and then tetraalkylorthotitanate may be added to tetraalkylorthosilicate. The alcohol by-produced by hydrolysis does not necessarily have to be removed, but it is preferable to reduce the amount by heating in advance.

The hydrolyzate obtained as described above is subjected to hydrothermal synthesis by adding water if necessary. The amount of water used for the hydrothermal synthesis is adjusted to be usually 15 to 100 equivalents, preferably 25 to 80 equivalents, relative to 1 mol of silicon atoms, in combination with water added during the hydrolysis reaction. In the hydrothermal synthesis reaction, this mixed solution is heated in a closed container under a temperature condition of usually 60 to 300 ° C., preferably 100 to 200 ° C., and usually 1 to 100 hours, preferably 6 to
It is carried out by maintaining this temperature for 50 hours. At this time, the pressure can be either one of self pressure and pressure, but usually it is pressure. It is not always necessary to stir the reaction system, and crystallization proceeds sufficiently even in a stationary state.

The solid powder crystallized by the hydrothermal synthesis treatment in this manner is thoroughly washed with ion-exchanged water and then subjected to a firing treatment. The temperature of the firing treatment is usually 300 to 700 ° C, preferably 350 to 600 ° C. Although the firing time is not particularly limited, the titanosilicate can be produced by performing the firing treatment usually for 1 to 50 hours, preferably for 2 to 20 hours.

In the present invention, as titanosilicate,
A synthetic zeolite material represented by the following general formula nSiO ₂ · (1-n) TiO ₂ (where n = 0.8 to 0.99), wherein the synthetic zeolite material is X-ray diffraction having an MFI type structure. Shows a pattern and shows an absorption near 960 cm ^{-1 in the} infrared absorption spectrum,
In addition to the pores with diameters between 5 and 6 angstroms inherent in type zeolites, titanosilicates with pores between 10 and 20 angstroms can be used.

The above-mentioned titanosilicate is a titanosilicate having an MFI type structure which is rich in thermal stability.
A compound having a relatively large molecular size without being influenced by diffusion rate control, since it has pores of 10 to 20 angstroms separately from pores of 5 to 6 angstroms which MFI zeolite originally has. Also, it has a high catalytic activity and is suitable as the titanosilicate of the present invention.

The above-mentioned titanosilicate is obtained by adding tetraalkyl orthosilicate, tetraalkyl orthotitanate and tetraalkylammonium hydroxide aqueous solution to the following molar ratio: SiO ₂ / TiO ₂ = 1.0 to 7.0 RN ⁺ / SiO ₂ = 0.1-1.0 (in the formula, RN + represents tetraalkylammonium hydroxide) H ₂ O / SiO ₂ = 10-100 are mixed, and this mixture is heated at a temperature of 100-250.
It is synthesized by hydrothermal synthesis at 30 ° C. for 30 minutes to 5 days.

The titanosilicate used in the present invention may contain boron, aluminum, phosphorus, calcium, if necessary.
Vanadium, chromium, manganese, iron, cobalt, nickel, copper, zinc, gallium, zirconium, or the like may be included, and an oxide source of these metals can be added to synthesize the heteroelement-containing titanosilicate.

The titanosilicate synthesized in the present invention may be used as it is or may be molded and used. When used by molding, a binder is generally used, but the kind of the binder is not particularly limited, and silica, alumina, etc. are used.

In the present invention, the noble metal of Group VIII of the periodic table carried on the titanosilicate is not particularly limited, but examples thereof include ruthenium, rhodium and
Palladium, iridium, platinum, etc. can be mentioned. Of these, palladium and platinum are preferably used from the viewpoint of catalytic activity. Further, the above-mentioned noble metals may be used alone, or may be used by mixing two or more kinds.

The noble metal compound as a raw material of these noble metals includes nitrates, sulfates, halides, inorganic complex salts,
Various inorganic compounds or organic compounds such as organic acid salts can be used, and among these, inorganic complex salts and halides are preferable. For example, in the case of palladium, palladium nitrate,
Examples thereof include inorganic acid salts such as palladium sulfate, halides such as palladium chloride, inorganic complex salts such as tetraamminedichloropalladium, and organic acid salts such as palladium acetate. Of these, tetraamminedichloropalladium and palladium chloride are more preferably used.

In the present invention, the method for supporting the noble metal compound on the titanosilicate is not particularly limited, and any known method such as impregnation method, precipitation method, kneading method or deposition method may be used using the above-mentioned raw materials. It can be carried. Of these, the impregnation method is more preferable because the supporting method is easy.
The titanosilicate-supported noble metal compound is then dried and, if desired, calcined.

In the present invention, the noble metal of Group VIII of the periodic table supported on titanosilicate must be in a metallic state. Therefore, the noble metal compound supported on the titanosilicate is subjected to reduction treatment before use. This reduction treatment may be performed in the catalyst preparation step or may be reduced in the reaction system. This reduction method is not particularly limited, but when it is carried out in the catalyst preparation step, a usual method, for example, a wet reduction method carried out in a solution of sodium formate, formaldehyde, hydrazine or the like, or hydrogen or carbon monoxide or the like with nitrogen. A dry reduction method in which a reducing gas diluted with an inert gas such as helium or helium is used in a gas phase can be used. When the reduction is carried out in the oxidation reaction system, titanosilicate carrying a noble metal compound may be suspended in the solvent used for the oxidation reaction, and the reducing gas may be passed through the suspension. The suspension becomes a catalyst suspension as it is, and the oxidation reaction can be started when the raw material gas is supplied.

The reduction treatment temperature of the noble metal compound is usually 0 to 5
The temperature is 00 ° C, preferably 5 to 160 ° C, more preferably 10 to 90 ° C. If the reduction treatment temperature is lower than 0 ° C, the noble metal compound may not be sufficiently reduced to a metallic state, and the catalytic activity may be substantially lowered. On the other hand, when the reduction treatment temperature exceeds 500 ° C., the degree of dispersion of the supported noble metal may decrease, and the selectivity of propylene oxide may decrease. The reduction treatment time is not particularly limited as long as the noble metal compound is sufficiently reduced, but it is generally 5 minutes to 24 hours.

In the catalyst of the present invention, the amount of the noble metal supported is usually 0.01 to 10% by weight, preferably 0.05 to 0.05, as a metal based on the total weight of the catalyst for the purpose of improving the reaction rate and economy. It is 5% by weight.

The oxidation reaction of the present invention is carried out in the liquid phase,
Specifically, it is performed using a solvent. The solvent is not particularly limited, for example, aliphatic alcohols such as methanol, ethanol, butanol, pentanol, hexanol, heptanol and octanol, glycols such as ethylene glycol and propylene glycol, dimethyl ether, diethyl ether. , Ethers such as tetrahydrofuran, dimethoxyethane, ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, ethylene glycol monopropyl ether, ethylene glycol monobutyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene Glycol ethers such as glycol monobutyl ether, acetone, methyl Ethyl ketone and ketones such as methyl isobutyl ketone,
Examples thereof include carboxylic acids such as acetic acid and water. Of these, water is preferably used from the viewpoint of easy handling. The above solvents may not be used alone, but may be used as a mixture of two or more kinds.

According to the present invention, the amount of the titanosilicate catalyst supporting a noble metal of Group VIII of the Periodic Table varies depending on the reaction mode. For example, in the case of a fixed bed continuous flow system, the reaction rate and heat There is no particular limitation as it is determined by the balance of payments. When the reaction is carried out in a batch system, a semi-batch system or a continuous flow system of a suspension bed, the amount of the catalyst used is usually 0.01 to 30% by weight, preferably 0.05 to 20% by weight, based on the solvent. If used in excess of this range, stirring of the catalyst suspension may be hindered.

In the method of the present invention, the reaction temperature in the direct oxidation of propylene with oxygen and hydrogen is 0 to 40 ° C., but preferably 10 to 35 ° C. in order to improve the reaction rate and suppress side reactions. is there. When the reaction temperature is lower than 0 ° C, the reaction rate becomes slow, while when the reaction temperature exceeds 40 ° C, side reactions tend to increase, and the propylene oxide selectivity may decrease. The reaction pressure is usually atmospheric pressure to 200 kg / cm ² , preferably atmospheric pressure to 50 kg / cm ² .
cm ² .

The propylene used in the present invention may be used in either gas or liquid state. When used in a liquid state, the reaction may be performed under pressure.

The propylene, oxygen and hydrogen gases supplied in this reaction may be diluted with an inert gas such as nitrogen, helium, argon, carbon dioxide and a mixed gas thereof. Oxygen in the air can also be used as oxygen. The supply amount of oxygen is not particularly limited because it changes depending on the reaction method and reaction conditions, but in order to improve the productivity and the conversion rate of oxygen, the supply amount of oxygen per unit weight (g) of the catalyst is usually 0.01 ml / min to 1000 ml
/ Min, preferably 0.1 ml / min to 500 ml
/ Min. The ratio of the raw material gas is not particularly limited and can be arbitrarily changed, but the following is preferable. Hydrogen / oxygen (molar ratio) is preferably 0.0
1 to 10. The propylene / oxygen (molar ratio) is preferably 0.1-10.

In order to improve the yield of propylene oxide, the volume hourly space velocity (GHSV) of the raw material gas including the inert gas and the catalyst is usually 1000 to 5000.
0 hr ^-1 , preferably 2000 to 40000 hr
^-1 . Here, GHSV means propylene and oxygen supplied per unit volume of catalyst at 20 ° C.,
Indicates the supply amount of hydrogen and inert gas.

In the present invention, the reaction method is not particularly limited, and a batch system in which the raw materials propylene, oxygen, hydrogen, catalyst and solvent are charged into the reaction apparatus at once, and propylene, oxygen and hydrogen are continuously blown into the reaction apparatus. A semi-batch system or a continuous system of a fixed bed or a suspension bed in which propylene, oxygen and hydrogen are continuously supplied and unreacted gas and a reaction solution are continuously extracted can be carried out.

The propylene oxide produced in this reaction is
It can be easily separated by a known method such as sequentially distilling the reaction mixture.

[0044]

EXAMPLES The present invention will be described in more detail below with reference to examples, but these examples show an outline of the present invention, and the present invention is not limited to these examples. . Example 1 Tetraethyl orthotitanate 43.9 was placed in a four-necked flask having an internal volume of 1000 ml equipped with a thermometer and a stirring device.
g and then 198 g of tetraethyl orthosilicate were added and mixed under a nitrogen stream. After cooling this mixed solution to 0 ° C., 347 g of a 25 wt% tetrapropylammonium hydroxide aqueous solution was added dropwise over 1 hour using a feed pump. Further, this liquid was stirred at room temperature for 1 hour to be aged. After stirring, the mixture became a homogeneous solution. The four-necked flask was heated to about 90 ° C. in an oil bath, and ethanol and water generated by hydrolysis were distilled off (262 ml).

Ion-exchanged water 59 was added to the mixture removed by distillation.
After adding 6 g, 450 ml thereof was put into a Hastelloy pressure-resistant reaction vessel having an internal volume of 500 ml equipped with a thermometer and a stirrer, and the temperature was raised to 170 ° C. under self-pressure for 2 hours.
The mixture was stirred for a time to perform hydrothermal synthesis. The contents of the autoclave were centrifuged and thoroughly washed with ion-exchanged water at 65 ° C. The white powder obtained was dried at 90 ° C. for 15 hours, and then 55
Firing was performed at 0 ° C. for 5 hours to obtain 21.5 g of titanosilicate. Table 1 shows the main peaks by X-ray diffraction (XRD) and the intensity ratio of each peak. This crystal structure showed an MFI type structure.

[0046]

[Table 1]

The titanosilicate showed a characteristic absorption at around 960 cm ^{-1 as} a result of infrared absorption spectrum measurement (FIG. 1), and the pore distribution measured by the N ₂ adsorption method was 10 to 20 angstrom. The presence of characteristic pores was shown (Fig. 2).

An aqueous solution of tetraamminepalladium (II) chloride was added to this titanosilicate so that the weight of palladium atom was 0.5% by weight with respect to the titanosilicate, and the mixture was stirred and mixed at room temperature for 1 hour. The suspension was evaporated to dryness and then diluted with nitrogen for 1 hour at 150 ° C. 17
Gas phase reduction was performed under a flow of volume% hydrogen to obtain a Pd-supported titanosilicate catalyst.

A glass atmospheric pressure semi-batch reactor having an internal volume of 100 ml equipped with a thermometer, a stirrer and a gas inlet was used as a catalyst, 0.5 g of the Pd-supported titanosilicate obtained in the Preparation Example was used as a solvent. 60 ml of water was added and stirred. Propylene, oxygen, hydrogen and nitrogen are added here to 30 mmol / hr, 80 mmol / hr and 20 mmo, respectively.
l / hr, 303 mmol / hr, the temperature was 26
The propylene was epoxidized by keeping the temperature at ℃. The outlet gas was led to an n-butanol trap in an ice bath and the entrained propylene oxide was collected in the trap. The reaction product was analyzed by gas chromatography. Reaction start 1
The results after 1 hour are shown in Table 2.

[0050]

[Table 2]

Example 2 An epoxidation reaction of propylene was carried out in the same manner as in Example 1 except that the reaction temperature was 35 ° C. Table 2 shows the results
Are shown together with.

Comparative Example 1 The epoxidation reaction of propylene was carried out in the same manner as in Example 1 except that the reaction temperature was 45 ° C. Table 2 shows the results
Are shown together with.

Example 3 The propylene epoxidation reaction was carried out in the same manner as in Example 1 except that the hydrogen supply rate was set to 15 mmol / hr. The results are also shown in Table 2.

Comparative Example 2 An propylene epoxidation reaction was carried out in the same manner as in Example 1 except that the hydrogen supply rate was 15 mmol / hr and the reaction temperature was 45 ° C. The results are also shown in Table 2.

Example 4 The epoxidation reaction of propylene was carried out in the same manner as in Example 1 except that the amount of hydrogen supplied was 10 mmol / hr. The results are also shown in Table 2.

Comparative Example 3 An propylene epoxidation reaction was carried out in the same manner as in Example 1 except that the hydrogen supply amount was 10 mmol / hr and the reaction temperature was 45 ° C. The results are also shown in Table 2.

Comparative Example 4 The propylene epoxidation reaction was carried out in the same manner as in Example 1 except that the oxygen supply rate was 20 mmol / hr and the reaction temperature was 45 ° C. The results are also shown in Table 2.

Example 5 A Pd-supporting titanosilicate catalyst was prepared in the same manner as in Example 1 except that the hydrothermal synthesis time was 6 hours, and the propylene epoxidation reaction was carried out in the same manner as in Example 1. went. The results are shown in Table 3.

[0059]

[Table 3]

Comparative Example 5 The hydrothermal synthesis time was 6 hours, and the oxygen supply amount was 20 mmmo.
A Pd-supporting titanosilicate catalyst was prepared in the same manner as in Example 1 except that the reaction temperature was set to 1 / hr and the reaction temperature was set to 45 ° C., and the epoxidation reaction of propylene was carried out in the same manner as in Example 1. . The results are also shown in Table 3.

Example 6 A Pd-supporting titanosilicate catalyst was prepared in the same manner as in Example 1 except that the aging time was 2 hours, and the propylene epoxidation reaction was carried out in the same manner as in Example 1. . The results are also shown in Table 3.

Example 7 A Pd-supporting titanosilicate catalyst was prepared in the same manner as in Example 1 except that the aging time was 4 hours, and the propylene epoxidation reaction was carried out in the same manner as in Example 1. . The results are also shown in Table 3.

Example 8 Tetraethyl orthotitanate 44.8 was placed in a 1000 ml four-necked flask equipped with a thermometer and a stirrer.
g, and then 195 g of tetraethyl orthosilicate were added and mixed under a nitrogen stream. After holding this mixed solution at 20 ° C., 346 g of a 25% by weight aqueous tetrapropylammonium hydroxide solution was added dropwise using a feed pump over 1 hour. Further, this liquid was stirred at room temperature for 1 hour to be aged. The four-necked flask was heated to about 90 ° C. in an oil bath, and ethanol and water generated by hydrolysis were distilled off (255 ml).

Ion-exchanged water 25 was added to the mixture removed by distillation.
After adding 0 g, 450 ml thereof was put into a Hastelloy pressure-resistant reaction vessel having an internal volume of 500 ml equipped with a thermometer and a stirrer, and the temperature was raised to 170 ° C. under self-pressure for 2 hours.
The mixture was stirred for a time to perform hydrothermal synthesis. The contents of the autoclave were centrifuged and thoroughly washed with ion-exchanged water at 65 ° C. The white powder obtained was dried at 90 ° C. for 15 hours, and then 55
The mixture was calcined at 0 ° C. for 5 hours to obtain 25.6 g of titanosilicate.

An aqueous solution of tetraamminepalladium (II) chloride was added to this titanosilicate so that the weight of palladium atoms was 0.5% by weight with respect to the titanosilicate, and the mixture was stirred and mixed at room temperature for 1 hour. The suspension was evaporated to dryness and then diluted with nitrogen for 1 hour at 150 ° C. 17
Gas phase reduction was performed under a flow of volume% hydrogen to obtain a Pd-supported titanosilicate catalyst. In a glass atmospheric pressure semi-batch type reactor having an internal volume of 100 ml equipped with a thermometer, a stirrer and a gas blowing port, 0.5 parts of Pd-supported titanosilicate was used as a catalyst.
g and 60 ml of water as a solvent were added and stirred. 30 mmol of propylene, oxygen, hydrogen and nitrogen
/ Hr, 80 mmol / hr, 20 mmol / hr, 3
It was supplied at 03 mmol / hr and the temperature was kept at 26 ° C. to carry out the epoxidation reaction of propylene. The results are also shown in Table 3.

[0066]

According to the present invention, in a method for producing propylene oxide by directly oxidizing propylene with oxygen and hydrogen in the presence of a catalyst in which a noble metal of Group VIII of the periodic table is supported on titanosilicate, Reaction temperature 0 to
By setting the temperature to 40 ° C., propylene oxide can be highly selectively produced without being affected by the raw material gas composition and the catalyst preparation conditions.

[Brief description of drawings]

FIG. 1 is a diagram showing an infrared absorption spectrum of a titanosilicate having an MFI structure obtained in Example 1.

FIG. 2 is a diagram showing a pore distribution of a titanosilicate having an MFI structure obtained in Example 1.

Claims (4)

[Claims] 1. A method for producing propylene oxide by directly oxidizing propylene with oxygen and hydrogen in the presence of a catalyst in which a noble metal of Group VIII of the periodic table is supported on titanosilicate, and a reaction temperature is 0 to 40 ° C. A method for producing propylene oxide, which comprises: 2. A synthetic zeolite substance represented by the following general formula nSiO _2. (1-n) TiO ₂ (wherein n = 0.8 to 0.999) as a titanosilicate, wherein The method for producing propylene oxide according to claim 1, wherein the zeolite material is a titanosilicate showing an X-ray diffraction pattern having a pentasil structure. 3. A synthetic zeolite substance represented by the following general formula nSiO _2. (1-n) TiO ₂ (wherein n = 0.8 to 0.99) as titanosilicate, wherein The zeolite material shows an X-ray diffraction pattern with an MFI type structure, and exhibits an absorption near 960 cm ^{-1 in the} infrared absorption spectrum.
The propylene oxide according to claim 1, characterized in that a titanosilicate having pores between 10 and 20 angstroms is used in addition to the pores having a diameter between 5 and 6 angstroms which the zeolite type originally has. Manufacturing method. 4. As the titanosilicate, a tetraalkyl orthosilicate, a tetraalkyl orthotitanate and an aqueous solution of tetraalkylammonium hydroxide are used in the following molar ratio: SiO ₂ / TiO ₂ = 1.0 to 7.0 RN ⁺ / SiO ₂ = 0.1-1.0 (in the formula, RN + represents tetraalkylammonium hydroxide) H ₂ O / SiO ₂ = 10-100 are mixed, and this mixture is heated at a temperature of 100-250.
The process for producing propylene oxide according to claim 1, wherein titanosilicate synthesized by hydrothermal synthesis is used at 30 ° C. for 30 minutes to 5 days.