JPH0797378A - Process for producing olefin oxide and catalyst therefor - Google Patents

Abstract

(57) [Summary] [Structure] When a lower olefin is oxidized in the gas phase with molecular oxygen to produce a corresponding olefin oxide, as a catalyst, an alkali metal salt of nitric acid, an alkaline earth metal salt,
A method for producing an olefin oxide, which comprises using a crystalline metallosilicate carrying at least one salt selected from a silver salt and a silver salt of nitrous acid. Effect According to the present invention, olefin oxide can be produced from olefin and molecular oxygen with high selectivity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing an olefin oxide, and more particularly to a method for producing an olefin oxide by oxidizing a lower olefin in the gas phase with molecular oxygen in the presence of a catalyst.

[0002]

BACKGROUND OF THE INVENTION Olefin oxide is industrially very important as an intermediate raw material for industrial chemicals, synthetic resins and rubbers, and in the presence of a catalyst, it is a lower olefin in the gas phase due to molecular oxygen. Various methods have been proposed to oxidize. For example, as a catalyst, a silver oxide catalyst (Japanese Patent Publication No. 53-39404, Japanese Patent Publication No. 53-12489,
US Pat. No. 4859786), copper / potassium phosphate catalysts (Chemical Society of Japan, 1978 , 468), phosphoric acid or phosphate ester catalysts (JP-B-49-33922), uranium dioxide catalysts (JP-B-SHO) 48-27281), thallium oxide
A method using a cobalt oxide type catalyst (Japanese Patent Publication No. 49-39962) is known. However, all of these methods have a problem that the selectivity of olefin oxide is low because a large amount of carbonyl compounds such as carbon dioxide, aldehydes and ketones are by-produced.

[0003]

In view of the above circumstances, the present inventors have conducted diligent studies to find out a better olefin oxidation catalyst, and as a result, have found that an alkali metal salt of nitric acid, an alkaline earth metal salt, The inventors have found that a crystalline metallosilicate catalyst supporting a salt such as a silver salt and a silver salt of nitrous acid gives an olefin oxide with a high selectivity, and completed the present invention.

That is, according to the present invention, when a lower olefin is oxidized in the gas phase with molecular oxygen to produce a corresponding olefin oxide, as a catalyst, an alkali metal salt of nitric acid, an alkaline earth metal salt, a silver salt and a sub-alloy thereof are used. It is intended to provide an industrially excellent method for producing an olefin oxide, characterized by using a crystalline metallosilicate carrying at least one salt selected from a silver salt of nitric acid. Hereinafter, the present invention will be described in detail.

The present invention relates to an olefin oxidation catalyst,
A crystalline metallosilicate carrying at least one salt selected from an alkali metal salt of nitric acid, an alkaline earth metal salt, a silver salt and a silver salt of nitrous acid is used. The crystalline metallosilicate used as a carrier is a crystalline solid containing a metal in addition to silicon and oxygen, and a metal containing titanium, gallium, chromium, zirconium, vanadium, nickel or the like is preferable. Among them, crystalline titanosilicate containing titanium is particularly preferably used. In addition to these metals, those containing other metals can also be used.

The ratio of the number of silicon atoms to the number of metal atoms in a crystalline metallosilicate (Si / Me atomic ratio) is usually 2
It is 0 to 10000, preferably 35 to 500. Si
/ Me atomic ratio is determined by the usual analytical means such as atomic absorption
It can be determined by a fluorescent X-ray method or the like. The crystalline metallosilicate can be produced by a known method (for example, JP-A-2-275850). There are various crystalline metallosilicates such as mordenite type and pentasil type, but the crystalline type is not particularly limited in the present invention. The pentasil type is preferred.

Examples of the alkali metal salt of nitric acid supported on the crystalline metallosilicate include lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate and cesium nitrate. Examples of the alkaline earth metal salts of nitric acid include barium nitrate, magnesium nitrate, calcium nitrate, strontium nitrate, and the like, and silver salts of nitric acid, silver salts of nitrous acid, silver nitrate, silver nitrite, and the like.

The amount of these salts supported is usually 0.01 to 50% by weight, preferably 0.1 to 50% by weight, based on the crystalline metallosilicate.
~ 30% by weight. To support these salts, an aqueous solution of the salt is usually used. For example, an olefin oxidation catalyst can be produced by impregnating this solution into a crystalline metallosilicate, drying and calcining. Firing is from 60
Usually performed at 200 ° C.

In the present invention, a mixed gas containing a lower olefin and molecular oxygen is brought into contact with the catalyst. Examples of the lower olefin include ethylene, propylene, 1-butene, 2-butene, isobutylene and 1-pentene. Is mentioned. A mixed gas containing olefin and molecular oxygen is
It may contain a gas inert to the reaction, such as carbon monoxide, carbon dioxide, nitrogen, helium, argon, water and saturated hydrocarbons. The mixed gas is nitrous oxide, nitric oxide, nitrogen dioxide, aldehydes, ketones, alcohols, halogenated hydrocarbons, esters,
You may contain nitriles etc.

The molar ratio of lower olefin to oxygen in the mixed gas is usually 1: 100 to 100: 1, though it varies depending on the reaction mode, the type of catalyst, the reaction temperature, the pressure and the like.
Preferably, it is 1:30 to 30: 1. When the mixed gas contains an inert gas, the amount thereof is usually 20 mol times or less with respect to propylene. The reaction temperature varies depending on the type of nitrate used and the like, but is usually about 100 to 400 ° C, preferably about 110 to 250 ° C. The reaction can be carried out under either atmospheric pressure or pressurized conditions.

[0011]

INDUSTRIAL APPLICABILITY According to the present invention, a crystalline metallosilicate carrying, as a catalyst, at least one salt selected from alkali metal salts of nitric acid, alkaline earth metal salts, silver salts and silver salts of nitrous acid. When used, the lower olefin can be oxidized in the gas phase with molecular oxygen to produce the corresponding olefin oxide with high selectivity.

[0012]

EXAMPLES The present invention will be described in more detail with reference to examples below, but the present invention is not limited to these examples. Reference Example 1 (Preparation of Carrier I) 73 g of 40% tetra-n-propylammonium hydroxide aqueous solution and water were placed in a 1.5-liter stainless steel autoclave.
351 g, 5 ml of an ethanol solution containing 1.73 g of titanium tetraisopropoxide, and tetraethyl orthosilicate
127.3 g of (Si (OC ₂ H ₅ ) ₄ and Al content of 10 ppm or less) were charged in this order and sufficiently stirred for 1 hour. Next, increase the internal temperature to 105
Hydrothermal synthesis was carried out for 96 hours while maintaining the temperature at ℃ and stirring at a rotation speed of 400 rpm or more. The white solid thus produced was collected by filtration and continuously washed with distilled water until the pH of the filtrate was around 7. The crystals obtained were dried at 120 ° C. for 16 hours. The dried crystals are further calcined under air flow at 500 to 530 ° C. for 4 hours,
A white powdery crystal, Carrier I was obtained. When the crystal was analyzed by an atomic absorption method, the Si / Ti atomic ratio was 100. It was confirmed to be a pentasil type by analyzing this crystal by X-ray analysis.

Reference Example 2 (Preparation of Carrier II) Hydrothermal synthesis, filtration, drying and calcination were carried out in accordance with Reference Example 1 except that 0.69 g of titanium tetraisopropoxide was used to obtain white crystals, Carrier II. . When the crystal was analyzed by an atomic absorption method, the Si / Ti atomic ratio was 250. This crystal is X
It was confirmed to be a pentasil type by analyzing by line analysis.

Reference Example 3 (Preparation of Carrier III) 50 g of 1,2-cyclohexanediol was added to a 500 ml flask.
Ethanol solution containing 0.52 g of titanium tetraethoxide 5
0 ml, tetraethyl orthosilicate 48.7 g, and 10% hydrochloric acid methanol solution 4.3 g were charged in this order, the internal temperature was kept at 80 ° C., the mixture was stirred for 3 hours, and water 11.5 g was added. Next, the produced gel was dried at 100 ° C. under reduced pressure and then calcined at 550 ° C. to obtain a white powdery solid and carrier III. When the solid was analyzed by an atomic absorption method, the Si / Ti atomic ratio was 96. It was confirmed that the solid was an amorphous type by analyzing the solid by X-ray analysis.

Example 1 15 g of an aqueous solution containing 0.05 g (0.59 mmol) of sodium nitrate was added to 5 g of carrier I, and water was evaporated with stirring to allow sodium nitrate to be carried, and then air was passed at 200 ° C. for 2 hours. It was calcined below to obtain catalyst A.

Example 2 A catalyst B was obtained in the same manner as in Example 1 except that 5 g of the carrier II was used instead of the carrier I.

Example 3 Catalyst C was prepared in the same manner as in Example 1 except that 2 mmol of cesium nitrate was used in place of sodium nitrate, and the calcination was carried out at 150 ° C. under a nitrogen stream.
Got Nitrogen analysis of this catalyst showed that it was about 2 mmol.
It was confirmed that the nitrate of was supported.

Examples 4 to 11 In Example 1, 2 mmol each of lithium nitrate, sodium nitrate, potassium nitrate, rubidium nitrate, calcium nitrate, strontium nitrate, silver nitrate and silver nitrite were used in place of sodium nitrate, and calcined under a nitrogen stream. ℃
Catalysts D to K were obtained by carrying out the procedure of Example 1 except that the above procedure was carried out.

Examples 12 to 15 In Example 1, 1 m of silver nitrate was used instead of sodium nitrate.
mol and potassium nitrate 1 mmol, silver nitrate 1 mmol and calcium nitrate 1 mmol, calcium nitrate 1 mmol and magnesium nitrate
1 mmol, calcium nitrate 1 mmol and sodium nitrate 1 mmol
Was carried out in the same manner as in Example 1 except that the calcination was carried out at 150 ° C. in a nitrogen stream to obtain catalysts L to O.

Comparative Example 1 A catalyst P was obtained in the same manner as in Example 1 except that 5 g of the carrier III was used in place of the carrier I and the calcination was carried out at 150 ° C. under a nitrogen stream.

Comparative Example 2 In 1 liter of an aqueous solution containing 25 g of sodium hydrogen carbonate,
1 liter of an aqueous solution containing 17 g of silver nitrate and 2.56 g of magnesium nitrate was added dropwise at a rate of 0.02 l / min. The produced yellow crystals were filtered, washed with 0.3 l of water three times, and then dried at room temperature for 18 hours. Then, after firing for 1 hour at 60 ℃ under nitrogen stream,
18 at 60 ° C under a mixed gas of hydrogen and nitrogen (molar ratio 1: 9)
The catalyst Q was obtained by calcination at 130 ° C. for 2 hours. When the nitrogen content of the catalyst was analyzed to determine it, nitrogen was not detected.

Example 16 A quartz glass reaction tube having an inner diameter of 0.5 cm was charged with 0.5 g of catalyst A molded into 24-48 mesh and kept at 200 ° C. A mixed gas consisting of propylene, oxygen and nitrogen (molar ratio 2: 1: 4) was supplied to this at a flow rate of 350 ml / hr for reaction. When the reaction product 1-2 hours after the initiation of the reaction was quantified by gas chromatography, the reaction rate of propylene was 0.62% and the selectivity of propylene oxide was 80%.

Example 17 The reaction was carried out in the same manner as in Example 1 except that 0.5 g of catalyst B was used in place of catalyst A in Example 16. The results are shown in Table 1.

Example 18 A quartz glass reaction tube having an inner diameter of 1.2 cm was filled with 2 g of catalyst C molded into a mesh of 24 to 48 and kept at 150 ° C. A mixed gas consisting of propylene and oxygen (molar ratio 2: 1)
Was supplied at a flow rate of 540 ml / hr for reaction. After starting the reaction
The reaction product for 1-2 hours was quantified by gas chromatography. The results are shown in Table 1. When the nitrogen analysis of the catalyst after the reaction was performed, the nitrogen content was almost the same as before the reaction.

Examples 19 to 30 and Comparative Examples 3 to 4 The reaction was performed in the same manner as in Example 18 except that 2 g of each of Catalysts D to Q was used in place of Catalyst C in Example 18. The results are shown in Table 1.

Example 31 Example 18 except that 2 g of catalyst O was used instead of catalyst C and 1-pentene was used instead of propylene.
The reaction was carried out in the same manner as in. When the reaction product 1-2 hours after the start of the reaction was quantified by gas chromatography, the reaction rate of 1-pentene was 0.82% and the selectivity of oxidized pentene was 76%.

Table 1 Propylene Oxidation Propylene Example Catalyst Carrier Support Reactivity (%) Selectivity (%) Example 16 AI NaNO ₃ 0.62 80 17 B II NaNO ₃ 0.35 85 18 C I CsNO ₃ 0.42 76 19 D I LiNO ₃ 0.89 61 20 E I NaNO ₃ 0.5 71 21 F I KNO ₃ 0.24 73 22 G I RbNO ₃ 0.29 74 23 H I Ca (NO ₃ ) ₂ 0.74 68 24 I I Sr (NO ₃ ) ₂ 0.32 62 25 J I AgNO ₃ 0.9 62 26 K I AgNO ₂ 0.79 64 27 L I AgNO ₃ -KNO ₃ 1.0 73 28 M I AgNO ₃ -Ca (NO ₃ ) ₂ 1.5 70 29 N I Mg (NO ₃ ) _2- Ca (NO ₃ ) ₂ 1.2 68 30 O I Ca (NO ₃ ) _2- NaNO ₃ 1.1 72 Comparative Example 3 P III AgNO ₃ 0.0 ^* -4 Q-Ag ₂ O-MgO 1.9 38 *: Only trace amounts of oxidized fluorene are produced.

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Claims (4)

[Claims] 1. An alkali metal salt of nitric acid, an alkaline earth metal salt, a silver salt and a silver salt of nitrous acid are used as catalysts for producing a corresponding olefin oxide by oxidizing a lower olefin in the gas phase with molecular oxygen. A method for producing an olefin oxide, which comprises using a crystalline metallosilicate carrying at least one salt selected from the group consisting of: 2. The method of claim 1 wherein the lower olefin is propylene. 3. A lower olefin oxidation catalyst comprising a crystalline metallosilicate carrying at least one salt selected from an alkali metal salt of nitric acid, an alkaline earth metal salt, a silver salt and a silver salt of nitrous acid. 4. The catalyst according to claim 3, wherein the lower olefin is propylene.