TWI621610B - Method for producing allyl acetate - Google Patents

Abstract

In the case of the production of allyl acetate by the reaction of oxygen, acetic acid, and propylene, the deterioration of the catalyst during long-term reaction is suppressed, and the catalyst is extended in life. In one embodiment of the present disclosure, the fourth periodic metal compound is filled with (a) palladium, (b) gold, and (c) having at least one element selected from the group consisting of copper, nickel, zinc, and cobalt. (d) an alkali metal salt compound and (e) a fixed bed tube type reactor in which a catalyst for producing allyl acetate is used to supply propylene, oxygen, and acetic acid as a raw material gas, and acetyl acetate is produced by a vapor phase contact oxidation reaction. In the ester method, in the reaction tube of the fixed-tube tubular reactor, two or more catalyst layers containing the catalyst for producing the allyl acetate are different in amount of the alkali metal salt compound (d) along the source gas. The flow direction is such that the amount of the (d) alkali metal salt compound supported on the (e) carrier is sequentially decreased from the inlet side to the outlet side of the fixed bed tube type reactor.

Description

Method for producing allyl acetate

This invention relates to a process for the production of allyl acetate from propylene, oxygen and acetic acid by vapor phase contact oxidation.

Allyl acetate is used as one of important industrial raw materials such as a solvent or a raw material for production of allyl alcohol.

A method for producing allyl acetate is a method in which a propylene, acetic acid, and oxygen are used as a raw material, and a gas phase reaction or a liquid phase reaction is used. As a catalyst for the reaction, a catalyst in which palladium is used as a main catalyst component and an alkali metal and/or an alkaline earth metal compound is used as a promoter to carry the catalyst on a carrier is widely used. For example, JP-A-2-91045 (Patent Document 1) discloses a method for producing allyl acetate using a catalyst in which palladium, potassium acetate, and copper are supported on a carrier.

The product is different from the case of allyl acetate. For example, Japanese Laid-Open Patent Publication No. 2003-525723 (Patent Document 2) discloses a method for producing a catalyst for producing vinyl acetate, which is based on ethylene, oxygen, and acetic acid. In the production of vinyl acetate as a starting material, by carrying palladium in the first step, carrying gold in the second step, and performing a reduction treatment, In the third step, copper (II) acetate and potassium acetate are carried to suppress the formation of carbon dioxide.

In the vinyl acetate production process using the above-mentioned catalyst, a gas phase reaction using a catalyst uniformly filled in a fixed bed multitubular reactor is generally used. On the other hand, U.S. Patent No. 8907123 (Patent Document 3) also discloses a method for suppressing the generation of a hot spot in the catalyst layer in the reaction tube, and the activity is different from the inlet to the outlet of the reaction tube of the reactor. The catalyst is divided into layers, and is filled in such a manner that the catalytic activity is sequentially increased toward the outlet of the reaction tube.

Further, in the general vinyl acetate production process using the above-mentioned catalyst, when a continuous reaction for a long period of several thousand hours is performed, since potassium acetate gradually flows out from the reaction tube a little during the process, it is necessary to The potassium acetate is continuously supplied to the catalyst. This is described in Japanese Laid-Open Patent Publication No. Hei 2-91045 (Patent Document 1) and the series "Catalyst and Economy", Vol. 35, No. 7 (1993), 467-470. Page (Non-Patent Document 1).

In the allyl acetate manufacturing procedure, the reaction is carried out at an acetic acid concentration lower than the vinyl acetate production procedure. For example, Japanese Patent Publication No. Hei 2-91045 (Patent Document 1) and International Publication No. 2009/142245 (Patent Document 4) disclose that the ratio of acetic acid in the material gas is preferably from 6 to 10% by volume. On the other hand, in the vinyl acetate production process, the ratio of acetic acid in the material gas is preferably 7 to 40% by volume as described in JP-A-2003-212824 (Patent Document 5).

[Previous Technical Literature] [Patent Literature]

[Patent Document 1] Japanese Patent Laid-Open No. 2-91045

[Patent Document 2] Japanese Patent Publication No. 2003-525723

[Patent Document 3] US Patent No. 8907123

[Patent Document 4] International Publication No. 2009/142245

[Patent Document 5] Japanese Patent Laid-Open Publication No. 2003-212824

[Non-patent literature]

[Non-Patent Document 1] Series "Ceramics and Economy", Vol. 35, No. 7 (1993), pp. 467-470 "Changes in Vinyl Acetate Process and Its Prospects"

However, the conventional method described in Patent Document 1 has a problem that the deterioration of the catalyst on the outlet side of the reactor is remarkably fast.

In the present invention, when the allyl acetate is produced by the reaction of oxygen, acetic acid, and propylene, the deterioration of the catalyst during long-term reaction is suppressed, and the catalyst is extended in life. For the subject.

The inventors of the present case and other research found that: potassium acetate, etc. The outflow rate of the alkali metal salt compound depends on the concentration of acetic acid in the reactor, and on the outlet side of the reactor, the concentration of acetic acid in the reaction is significantly lower than that on the inlet side of the reactor, and thus in the catalyst on the outlet side of the reactor The supplied alkali metal salt compound is accumulated to significantly accelerate the deterioration of the catalyst. Further, it has been found that the catalyst for the production of allyl acetate is opposite to the catalyst for the production of vinyl acetate, and the more the amount of the alkali metal salt compound supported on the carrier, the higher the initial activity of the catalyst, by the fixed bed. In the reaction tube of the tubular reactor, two or more catalyst layers having different amounts of alkali metal salt compounds are disposed along the reaction direction so that the amount of the alkali metal salt compound supported on the carrier is from the inlet of the fixed bed tubular reactor. The lateral outlet side is sequentially lowered, and the concentration gradient of the alkali metal salt compound is reduced to suppress local catalyst deterioration, and as a result, the performance of the catalyst can be effectively exhibited. Further, Patent Document 3 also sets an example in which a catalyst for producing vinyl acetate is formed by sequentially decreasing the concentration of an alkali metal salt compound toward the outlet side of a fixed bed tube type reactor, and is directed toward the outlet of the reaction tube. Since the catalyst activity is increased on the side, it is a technical idea contrary to the present invention which suppresses the deterioration of the catalyst on the outlet side of the reaction tube and prolongs the life of the catalyst.

That is, the present invention relates to the following [1] to [8].

[1]

A method for producing allyl acetate, characterized by filling a fourth periodic metal compound having at least one element selected from the group consisting of (a) palladium, (b) gold, and (c) selected from the group consisting of copper, nickel, zinc, and cobalt And (d) an alkali metal salt compound and (e) a fixed bed tube reactor in which a catalyst for producing allyl acetate is used as a carrier, and propylene, oxygen, and acetic acid are supplied as a raw material gas, and are produced by a vapor phase contact oxidation reaction. In the method of producing allyl acetate, in the reaction tube of the fixed bed tubular reactor, two or more catalysts containing the catalyst for producing the allyl acetate ester having different amounts of the alkali metal salt compound (d) are contained. The layer is disposed in the flow direction of the material gas so that the amount of the (d) alkali metal salt compound supported on the (e) carrier is sequentially decreased from the inlet side to the outlet side of the fixed bed tubular reactor.

[2]

The method for producing allyl acetate according to [1], wherein (e) the carrier (a) carrier (d) of the reaction tube has a loading amount (g) per 1 g of the (d) alkali metal salt compound. The (e) carrier in the catalyst layer on the outlet side is 1.2 to 3.0 times the amount (g) of the (d) alkali metal salt compound per 1 g of the carrier.

[3]

The method for producing allyl acetate according to any one of [1] or [2] wherein the reaction tube is a straight tube, the catalyst layer is two layers, and the catalyst layer and the outlet side of the inlet side of the reaction tube The ratio of the length of the catalyst layer in the flow direction of the material gas is 4:1 to 1:4.

[4]

The method for producing allyl acetate according to any one of [1] to [3] wherein the fixed bed tubular reactor is of a multitubular type.

[5]

The method for producing allyl acetate according to any one of [1] to [4] wherein (d) the alkali metal salt compound is at least one selected from the group consisting of potassium acetate, sodium acetate, and barium acetate.

[6]

The method for producing allyl acetate according to any one of [1] to [5], wherein (c) The fourth period metal compound is a compound having copper or zinc.

[7]

The method for producing allyl acetate according to any one of [1] to [6] wherein (c) the fourth period metal compound is copper acetate.

[8]

The method for producing allyl acetate according to any one of [1] to [7] wherein, in any one of the catalyst layers, the (a) palladium, (b) of the catalyst for producing allyl acetate The mass ratio of gold, (c) the fourth cycle metal compound and (d) the alkali metal salt compound are (a): (b): (c): (d) = 1: 0.00125 to 22.5: 0.02 to 90: 0.2~450.

According to the method for producing allyl acetate of the present invention, the life of the catalyst can be improved. As a result, by using this production method, the production cost of allyl acetate can be reduced, and allyl acetate can be efficiently produced.

Fig. 1A is a schematic view showing a filling position of the catalyst of the first embodiment.

Fig. 1B is a schematic view showing the filling position of the catalyst of Comparative Example 1.

Fig. 1C is a schematic view showing the filling position of the catalyst of Comparative Example 2.

In the following, the preferred embodiments of the present invention are described, but the present invention is not limited to the embodiments, and it should be understood that the invention can be applied to various applications within the spirit and scope of the invention.

In the present invention, two or more catalyst layers containing a catalyst for producing allyl acetate having a different amount of an alkali metal salt compound are placed in a reaction tube of a fixed bed tubular reactor along the flow direction of the material gas ( The reaction direction) is such that the amount of the alkali metal salt compound supported on the carrier is sequentially decreased from the inlet side to the outlet side of the fixed bed tube type reactor.

<catalyst>

The catalyst for producing allyl acetate used in the present invention is a fourth periodic metal compound having (a) palladium, (b) gold, and (c) having at least one element selected from the group consisting of copper, nickel, zinc, and cobalt. And (d) an alkali metal salt compound and (e) each component of the carrier. Hereinafter, these components will be described.

(a) Palladium

In the present invention, (a) palladium may have any valence number, preferably metal palladium. The "metal palladium" in the present invention means a valence having a zero valence. The metal palladium can usually be obtained by reducing divalent and/or tetravalent palladium ions using hydrazine, hydrogen or the like as a reducing agent. At this time, not all of the palladium is in a metallic state.

As a raw material of palladium, it is not particularly limited, and metal palladium can be used. Or a palladium precursor that can be converted to metallic palladium. Examples of the palladium precursor include palladium chloride, palladium nitrate, palladium sulfate, sodium palladium chloride, potassium palladium chloride, ruthenium palladium chloride, palladium acetate and the like. Sodium palladium chloride is preferably used. As the palladium precursor, a single compound may be used, or a plurality of compounds may be used in combination.

The mass ratio of (a) palladium to (e) carrier in the catalyst for producing allyl acetate is preferably (a): (e) = 1:10 to 1:1000, more preferably (a): e) = 1:20~1:500. This ratio is defined as the ratio of the mass of the palladium element to the mass of the support.

(b) gold

In the present invention, (b) the gold is supported on the carrier in the form of a compound containing a gold element, but it is preferred that the metal is finally substantially entirely metal gold. The term "metal gold" as used in the present invention means a valence having a zero price. Metallic gold can usually be obtained by reducing monovalent and/or trivalent gold ions using hydrazine, hydrogen or the like as a reducing agent. At this time, not all gold is in a metallic state.

The raw material of gold is not particularly limited, and metal gold or a gold precursor which can be converted into metal gold can be used. Examples of the gold precursor include chloroauric acid, sodium chloride chloride, potassium chlorate, and the like. Preferably, gold chloride acid or sodium chloride chloride is used. As the gold precursor, a single compound may be used, or a plurality of compounds may be used in combination.

The quality of (b) gold and (e) carrier in the catalyst for producing allyl acetate is preferably (b): (e) = 1:40 to 1:65000, more preferably (b): (e) =1:550~1:32000, and even more preferably (b): (e)=1:750~1:10000. This ratio is defined as the ratio of the mass of the gold element to the mass of the carrier.

The amount of (b) gold in the catalyst for producing allyl acetate is preferably 0.125 to 2250 parts by mass, more preferably 0.25 to 14 parts by mass, even more preferably 0.8 to 10 parts by mass based on 100 parts by mass of palladium. Share. The mass fraction of gold and palladium is based on the mass of each element. By using such a general amount of gold, the activity of the catalyst in the allyl acetate formation reaction can be maintained in a well-balanced manner with the allyl acetate selectivity.

(c) a fourth periodic metal compound having at least one element selected from the group consisting of copper, nickel, zinc, and cobalt

In the present invention, (c) the fourth periodic metal compound may be a soluble salt such as a nitrate, a carbonate, a sulfate, an organic acid salt or a halide selected from at least one element selected from the group consisting of copper, nickel, zinc and cobalt. . The fourth periodic metal compound is preferably a compound having copper or zinc in terms of further improving the catalytic activity. The organic acid salt may, for example, be an acetate. In general, a compound which is easily available and is water-soluble is preferred. Preferred examples of the compound include copper nitrate, copper acetate, nickel nitrate, nickel acetate, zinc nitrate, zinc acetate, cobalt nitrate, and cobalt acetate. Among these, copper acetate is preferred from the viewpoint of stability of raw materials and ease of availability. As the metal compound of the fourth period, a single compound may be used, or a plurality of compounds may be used in combination.

The quality of the (c) fourth-period metal compound and the (e) carrier in the catalyst for producing allyl acetate is preferably (c): (e) = 1:10 to 1:500, more preferably (c) :(e)=1:20~1:400. This ratio is defined as the ratio of the total mass of copper, nickel, zinc and cobalt elements to the mass of the carrier.

(d) alkali metal salt compound

In the present invention, as the alkali metal salt compound (d), a hydroxide, an acetate, a nitrate, a hydrogencarbonate or the like of lithium, sodium, potassium, rubidium or cesium may be used. Potassium acetate, sodium acetate, and cesium acetate are preferred, and potassium acetate and cesium acetate are more preferred. As the alkali metal salt compound, a single compound may be used, or a plurality of compounds may be used in combination.

The quality of the (d) alkali metal salt compound and the (e) carrier in the catalyst for producing allyl acetate is preferably (d): (e) = 1:2 to 1:50, more preferably (d): (e) = 1:3~1:40. This ratio is defined as the ratio of the mass of the alkali metal salt compound to the mass of the carrier.

(e) carrier

The (e) carrier used in the present invention is not particularly limited, and a porous material generally used as a catalyst carrier can be used. Examples of preferred carriers include cerium oxide, aluminum oxide, cerium oxide-alumina, diatomaceous earth, montmorillonite, titanium oxide, and zirconium oxide. Better use of cerium oxide. When the carrier containing cerium oxide as a main component is used as the carrier, the cerium oxide content of the carrier is preferably at least 50% by mass, more preferably at least 90% by mass based on the mass of the carrier.

The carrier has a specific surface area measured by the BET method of preferably from 10 to 1,000 m ² /g, particularly preferably from 100 to 500 m ² /g. The bulk density of the carrier is preferably in the range of 50 to 1000 g/L, and particularly preferably in the range of 300 to 500 g/L. The water absorption of the carrier is preferably from 0.05 to 3 g/g, particularly preferably from 0.1 to 2 g/g. In the pore structure of the carrier, the average pore diameter is preferably in the range of 1 to 1000 nm, particularly preferably in the range of 2 to 800 nm. If the average pore diameter is less than 1 nm, it is difficult to diffuse the gas. On the other hand, if the pore diameter is more than 1000 nm, the specific surface area of the carrier is too small, and there is a possibility of lowering the activity of the catalyst.

The water absorption rate of the carrier in the present invention means a value measured in accordance with the following procedure.

1. Place about 5g of the balance scale carrier and place it in a 100cc beaker. Set the quality at this time to w ₁ .

2. Add about 15 mL of pure water (ion exchange water) to the beaker so that the carrier is completely covered.

3. Leave for 30 minutes.

4. Remove the pure water from the carrier from the carrier.

5. Lightly press with a paper towel or the like to remove water adhering to the surface of the carrier until the gloss of the surface disappears.

6. The total quality of the fine scale carrier and pure water. The mass at this time is w ₂ .

7. The water absorption of the carrier was calculated from the following formula.

Water absorption rate (g/g-carrier) = (w ₂ - w ₁ ) / w ₁

Thus, the water absorption amount (g) of the carrier is calculated by the water absorption rate (g/g-carrier) of the carrier × the mass (g) of the carrier used.

The shape of the carrier is not particularly limited. Specifically, it may, for example, be a powder, a sphere, a pellet or the like, but is not limited thereto. The optimum shape can be selected depending on the reaction form, reactor, etc. used.

The particle size of the carrier is also not particularly limited. When the carrier is spherical, the particle diameter thereof is preferably in the range of 1 to 10 mm, more preferably in the range of 2 to 8 mm. When the tubular reactor is filled with a catalyst and subjected to a gas phase reaction, if the particle diameter is less than 1 mm, a large pressure loss occurs when the gas flows, and there is a possibility that an effective gas circulation cannot be performed. On the other hand, when the particle diameter is more than 10 mm, the reaction gas does not easily diffuse into the inside of the catalyst, and the catalyst reaction cannot be efficiently performed.

(f) alkali solution

The (f) alkali solution used in the step 2 of the catalyst production step described below is not particularly limited, and any alkaline solution can be used. Examples of the raw material of the alkali solution include hydroxides of alkali metals or alkaline earth metals, bicarbonates of alkali metals or alkaline earth metals, carbonates of alkali metals or alkaline earth metals, silicates of alkali metals or alkaline earth metals, and the like. Basic compound. The alkali metal is preferably lithium, sodium, and potassium, and the alkaline earth metal is preferably lanthanum and cerium. The particularly preferable basic compound may, for example, be sodium metasilicate, potassium metasilicate, sodium hydroxide, potassium hydroxide or barium hydroxide. A part or all of the palladium compound and a part or all of the gold compound may be converted into an oxide or a hydroxide by contact with an alkali solution.

The basic compound is preferably used in excess in molar excess with respect to the total of (a) palladium and (b) gold. For example, the amount of the basic compound used is preferably from 1 to 3 moles per 1 mole of (a) palladium, more preferably from 1.2 to 2.5 moles, and preferably from (b) gold per mole. It is 2 to 10 moles, more preferably 3 to 8 moles.

The solvent for forming the alkali solution is not particularly limited, and examples thereof include water, methanol, ethanol, and the like.

<Catalyst manufacturing step>

The production step of the catalyst is not particularly limited as long as the components (a) to (d) can be carried on the carrier (e), and it is preferably produced in accordance with the following procedure.

Step 1. Step of preparing a homogeneous solution containing a palladium raw material and a gold raw material, and contacting the obtained uniform solution with the (e) carrier to carry the palladium raw material and the gold raw material on the carrier.

Step 2. The step of contacting the (f) alkali solution with the carrier obtained in the step 1

Step 3. The step of reducing the carrier obtained in the step 2, and

Step 4. Step of carrying (c) the fourth cycle metal compound and (d) the alkali metal salt compound on the carrier obtained in the step 3

Next, explain each step.

step 1

In this step, a homogeneous solution containing a palladium raw material (metal palladium or a precursor thereof) and a gold raw material (metal gold or a precursor thereof) is prepared, and the obtained homogeneous solution is impregnated with a carrier to carry out the support of the raw materials. The carrier state of these raw materials to the carrier is preferably a so-called "egg shell type". In this case, the method of supporting the carrier by the homogeneous solution containing the palladium raw material and the gold raw material is not particularly limited as long as it is a method of finally obtaining the eggshell-type carrier catalyst. "The eggshell type The term "catalyst" refers to a distribution state of an active ingredient (for example, metal palladium) in a carrier particle or a molded body, and most of the active component is present on the carrier particle or a supporting catalyst on the outer surface of the molded body. Specific examples of the method for producing the eggshell-type carrier catalyst include a suitable solvent for dissolving the raw material in water or acetone, or an inorganic acid or an organic acid such as hydrochloric acid, nitric acid or acetic acid, or a solution thereof. a method of directly or indirectly carrying it on the surface layer of a carrier. Examples of the method of directly carrying it include an impregnation method and a spray method. The method of carrying it in between and grounding is as follows, a uniform solution containing a palladium raw material and a gold raw material is uniformly supported on a carrier (step 1), and then impregnated by contact with (f) an alkali solution ( In the step 2), the internal palladium raw material and the gold raw material are moved to the surface, and then the method of reduction (step 3) is performed.

The support of the palladium raw material and the gold raw material to the carrier can be carried out by preparing a homogeneous solution containing the palladium raw material and the gold raw material, and contacting the solution with a suitable amount of the support. More specifically, the palladium raw material and the gold raw material are dissolved in a suitable solvent such as water or acetone, or an inorganic acid such as hydrochloric acid, nitric acid or acetic acid or an organic acid or a solution thereof to prepare a homogeneous solution, and the resulting solution is obtained. The homogeneous solution is impregnated with the support to obtain the impregnated support (A). The drying may be carried out immediately after impregnation, but the drying step is omitted and the step 2 is carried out, since the step can be omitted.

Step 2

This step is a step of obtaining the impregnated support (B) by contacting the (f) alkali solution with the impregnated support (A) obtained in the step 1. The alkaline substance used in the step 2 can be used as it is, but it is preferably used as a solution. Form supply. The alkaline solution is preferably a solution of water and/or alcohol. The contact conditions of the impregnated carrier (A) with the alkali solution are not particularly limited, and the contact time is preferably in the range of 0.5 to 100 hours, more preferably in the range of 3 to 50 hours. If it is less than 0.5 hours, there is a problem that sufficient performance cannot be obtained; on the other hand, if it exceeds 100 hours, there is damage to the carrier.

The contact temperature is not particularly limited, and is preferably in the range of 10 to 80 ° C, more preferably in the range of 20 to 60 ° C. If the contact is made at a temperature lower than 10 ° C, there is a possibility that a sufficient conversion speed cannot be obtained. On the other hand, when it exceeds 80 ° C, there is a possibility of coagulation of palladium or gold.

Step 3

This step is a step of subjecting the impregnated carrier (B) obtained in the step 2 to a reduction treatment. For the reduction method, either liquid phase reduction or gas phase reduction can be employed. The metal-supported carrier obtained in this step is used as a metal-supporting carrier (C).

Liquid phase reduction can also be carried out in any of a non-aqueous system and an aqueous system using an alcohol or a hydrocarbon. As the reducing agent, a carboxylic acid and a salt thereof, an aldehyde, hydrogen peroxide, a saccharide, a polyhydric phenol, a boron compound, an amine, an anthracene or the like can be used. Examples of the carboxylic acid and the salt thereof include oxalic acid, potassium oxalate, formic acid, potassium formate, potassium citrate, ammonium citrate and the like. Examples of the aldehyde include formaldehyde, acetaldehyde and the like. Examples of the saccharide include glucose and the like. Examples of the polyhydric phenol include hydroquinone and the like. Examples of the boron compound include diborane, sodium borohydride and the like. Among these, it is preferred to use hydrazine, formaldehyde, acetaldehyde, hydroquinone, sodium borohydride, or lemon. Potassium citrate is better for use.

When the liquid phase is reduced, the temperature thereof is not particularly limited, and it is preferably a liquid phase temperature of from 0 to 200 ° C, more preferably from 10 to 100 ° C. If the temperature is lower than 0 ° C, a sufficient reduction rate may not be obtained. On the other hand, if it exceeds 200 ° C, agglomeration of palladium or gold may occur. The reduction time is not particularly limited, and the reduction time is preferably in the range of 0.5 to 24 hours, more preferably in the range of 1 to 10 hours. If it is less than 0.5 hours, there is a possibility that the reduction cannot be sufficiently carried out; on the other hand, if it exceeds 24 hours, there is a tendency to cause aggregation of palladium or gold.

The reducing agent used for the gas phase reduction is selected from olefins such as hydrogen, carbon monoxide, alcohols, aldehydes, ethylene, propylene, isobutylene and the like. Hydrogen or propylene is preferably used as the reducing agent.

When the gas phase reduction is carried out, the temperature thereof is not particularly limited, and the impregnated carrier (B) is preferably heated to a range of from 30 to 350 ° C, more preferably to a range of from 100 to 300 ° C. When the temperature is lower than 30 ° C, a sufficient reduction rate cannot be obtained. On the other hand, if it exceeds 300 ° C, the coagulation of palladium or gold may occur. The reduction time is not particularly limited, and the reduction time is preferably in the range of 0.5 to 24 hours, more preferably in the range of 1 to 10 hours. If it is less than 0.5 hours, there is a possibility that the reduction cannot be sufficiently carried out; on the other hand, if it exceeds 24 hours, there is a tendency to cause aggregation of palladium or gold.

The treatment pressure of the gas phase reduction is not particularly limited, and is preferably in the range of 0.0 to 3.0 MPaG (gauge pressure), more preferably in the range of 0.1 to 1.0 MPaG (gauge pressure), from the viewpoint of equipment.

In the standard state, the supply of the reducing agent in the gas phase reduction is preferably in the range of 10 to 15000 hr ^-1 in the space velocity (hereinafter referred to as SV), and particularly preferably in the range of 100 to 8000 hr ^-1 .

The gas phase reduction can be carried out at various concentrations of reducing substances, and an inert gas can also be added as a diluent as needed. Examples of the inert gas include helium gas, argon gas, nitrogen gas, and the like. Hydrogen, propylene, or the like may be present in the presence of vaporized water for reduction.

The catalyst before the reduction treatment may be filled in a reactor, and after reduction with propylene, oxygen and acetic acid may be further introduced to produce allyl acetate.

For the reduced carrier, water can also be washed as needed. Washing can be carried out in a flow-through manner or in batch mode. The washing temperature is preferably in the range of 5 to 200 ° C, more preferably in the range of 15 to 80 ° C. The washing time is not particularly limited. It is preferable to select sufficient conditions for carrying out the removal of poor residual impurities. Examples of the poor impurities include sodium, chlorine, and the like. After washing, it can also be heated and dried according to requirements.

Step 4

This step is a step of carrying (c) the fourth periodic metal compound and (d) the alkali metal salt compound on the metal-supporting carrier (C) obtained in the step 3.

By impregnating the metal-supporting carrier (C) with a solution containing the desired amount of the (c) fourth-period metal compound and the (d) alkali metal salt compound and having a water absorption amount of the carrier of 0.9 to 1.0 times. Dry to carry each compound. The solvent at this time is not particularly limited. A solution in which the alkali metal salt compound to be used is dissolved in a mass of 0.9 to 1.0 times the amount of water absorbed by the carrier can be used. Various solvents. The solvent is preferably water. In the present invention, the amount of the alkali metal salt compound supported can be adjusted by changing the concentration of the solution. The drying temperature and time are not particularly limited.

<catalyst composition>

The mass ratio of (a), (b), (c) and (d) is preferably (a): (b): (c): (d) = 1: 0.00125 to 22.5: 0.02 to 90: 0.2~ 450, more preferably (a): (b): (c): (d) = 1: 0.0025 ~ 0.14: 0.04 ~ 50: 0.4 ~ 250, especially good (a): (b): (c): (d) = 1: 0.008 - 0.1: 0.04 - 50: 0.4 - 250. Any of the catalyst layers preferably satisfies the above mass ratio. For the purposes of (a), (b) and (c), based on the mass of the constituent elements; in the case of (d), based on the mass of the alkali metal salt compound.

The carrying amount and composition ratio of the metal element contained in the catalyst for producing allyl acetate can be analyzed by a high frequency inductively coupled plasma atomic emission spectrometer (hereinafter referred to as "ICP") or fluorescent X-ray analysis (hereinafter referred to as It is measured by chemical analysis such as "XRF") and atomic absorption spectrometry.

In the example of the measurement method, a predetermined amount of the catalyst is pulverized by a mortar or the like to form a uniform powder, and then the powdery catalyst is added to an acid such as hydrofluoric acid or aqua regia and heated and stirred to dissolve it. And adjust to a uniform solution. Next, the solution was diluted to a suitable concentration with pure water, and the solution was quantitatively analyzed by ICP.

<fixed bed tubular reactor>

The "fixed bed tubular type reactor" in the present invention is a tubular type reaction tube It is filled with a catalyst (which is carried on a carrier) as a fixed bed. The reaction substrate is supplied to the reaction tube in the gas phase, and the reaction product is discharged from the outlet of the reaction tube. The tubular reaction tube is preferably a straight tube type from the viewpoints of equipment manufacturing and maintenance, workability at the time of catalyst filling and replacement, and removal of reaction heat. The reaction tube is preferably placed in the vertical direction (longitudinal direction) from the viewpoint of the filling of the catalyst and the workability of the extraction. Since the vapor phase contact oxidation reaction of the present invention is an exothermic reaction, a system in which the heat of reaction is removed from the outside of the reaction tube is generally used. The inner diameter, the outer diameter, the length, and the material of the reaction tube, the reaction heat removal device, and the reaction heat removal method are not particularly limited, and the reaction is performed in consideration of the heat exchange area associated with the reaction heat removal and the pressure loss inside the reaction tube. The inner diameter of the tube is preferably 10 to 50 mm, and the length thereof is preferably 1 to 6 m. Since there is a limitation in increasing the inner diameter of one reaction tube in order to remove the heat of reaction, the reactor can also be of a multi-tube type. Industrial manufacturing equipment can ensure production by using hundreds to thousands of reaction tubes. The reaction tube is not limited as long as it is made of a material having corrosion resistance and heat resistance. The material of the reaction tube may, for example, be a SUS material, in particular, SUS316L.

Conventionally, the catalyst is uniformly filled in the reactor in the same specification, and in the present invention, the catalyst is filled into the (d) alkali metal salt compound from the inlet side to the outlet side of the fixed bed tubular reactor. The holding capacity is reduced in order. In other words, the catalyst layer having a different supporting amount of the alkali metal salt compound is filled in the reaction tube in a plurality of layers in such a manner that the amount of the alkali metal salt compound is sequentially decreased in the flow direction of the material gas. The number of catalyst layers may be two or more layers, and may be three or more layers. Alkali metal salt compound The amount of load is continuously reduced (gradient). The catalyst layer is preferably two or three layers based on the workability of the catalyst filling in an actual factory, and even if it is two layers, the object of the present invention can be sufficiently achieved.

The catalyst layer in which the amount of the (d) alkali metal salt compound is different is filled in the reaction tube in such a manner that the amount of the alkali metal salt compound is sequentially decreased, and the (e) carrier is used per 1 g of the base. The catalyst having a small amount of supported metal salt (g) may be sequentially filled from the outlet side. The carrier (g) of the carrier in the catalyst layer on the most inlet side of the reaction tube is preferably the amount of the alkali metal salt compound per 1 g of the carrier in the catalyst layer on the outlet side. The carrying amount (g) is 1.2 to 3.0 times, more preferably 1.3 to 2.4 times, and even more preferably 1.3 to 2.1 times. The effect of the present invention can be improved by making the above-described carrying amount ratio 1.2 times or more. On the other hand, by taking 3.0 times or less, deterioration of the catalyst can be suppressed.

The ratio of the amount of the (d) alkali metal salt compound supported in the catalyst layer is the value at the start of the reaction. The amount of the alkali metal salt compound of each catalyst layer changes during a period of several hundred to several thousands of hours of reaction. In the case of the vertical reaction tube, the alkali metal salt compound of the catalyst layer on the upper side (inlet side) may move toward the catalyst layer on the lower side (outlet side), and may be gradually discharged from the reaction tube. At this time, it is preferred to supply the alkali metal salt compound corresponding to the outflow amount to the reactor.

(d) The amount of the component other than the alkali metal salt compound is generally the same in all the catalyst layers, but it may be changed to improve the overall reaction efficiency.

When the catalyst layer is two layers, the length ratio of the catalyst layer is preferably Reactor inlet side: outlet side = 4:1~1:4, more preferably reactor inlet side: outlet side = 3:2~1:4, especially preferably 3:2~2:3.

<Manufacture of allyl acetate>

Preferably, the reaction for producing allyl acetate is carried out in the gas phase using propylene, oxygen and acetic acid as raw materials. Preferably, it is advantageous to use a fixed bed flow reaction in which the above-mentioned catalyst is filled with a corrosion-resistant reaction tube. The reaction formula is as follows: CH ₂ =CHCH ₃ +CH ₃ COOH+1/2O ₂ →CH ₂ =CHCH ₅ OCOCH ₃ +H ₂ O

The raw material gas system contains propylene, oxygen, and acetic acid, and nitrogen, carbon dioxide, a rare gas, or the like can be further used as a diluent as needed.

The material gas preferably has a composition in the range of acetic acid: propylene: oxygen = 1:1 to 12: 0.5 to 2 in terms of molar ratio.

In the reaction for producing allyl acetate, if water is present in the reaction system, the allyl acetate production activity and maintenance of the catalyst are remarkably effective. The water vapor is preferably present in a range of 0.5 to 25 % by volume in the gas supplied to the reaction.

Among the gases supplied to the reaction, propylene is preferably used in a high purity, but may be mixed with a lower saturated hydrocarbon such as methane, ethane or propane. Oxygen may also be supplied by an inert gas such as nitrogen or carbon dioxide, for example, in the form of air, but in the case of circulating a reaction gas, generally speaking It is advantageous to use a high concentration, preferably 99% by volume or more of oxygen.

The reaction temperature is not particularly limited. It is preferably in the range of 100 to 300 ° C, more preferably in the range of 120 to 250 ° C. The reaction pressure is practically advantageous from the viewpoint of equipment, and is in the range of 0.0 to 3.0 MPaG (gauge pressure), but is not particularly limited. More preferably, it is in the range of 0.1 to 1.5 MPaG (gauge pressure).

When the reaction is carried out in a fixed bed flow reaction, the raw material gas is preferably supplied to the catalyst in a range of space velocity: SV = 10 to 15000 hr ^-1 in a standard state, and is preferably supplied to the catalyst in a range of 300 to 8000 hr ^-1 .

[Examples]

Hereinafter, the present invention will be further described based on examples and comparative examples, but the present invention is not limited thereto.

Production Example 1 Production of Catalyst A

Using a ceria spherical carrier (spherical diameter: 5 mm, specific surface area: 155 m ² /g, water absorption: 0.85 g/g, hereinafter referred to as "cerium oxide carrier"), the production of the catalyst A was carried out in accordance with the following procedure.

step 1

4.1 L of an aqueous solution containing 199 g of sodium palladium chloride and 4.08 g of sodium chloride chloride tetrahydrate was prepared as an A-1 solution. 12 L of a cerium oxide carrier (body density: 473 g/L, water absorption amount: 402 g/L) was added thereto, and the A-1 solution was impregnated therein to absorb the entire amount.

Step 2

427 g of sodium metasilicate citrate was dissolved in pure water, and it was diluted with pure water to a total amount of 8.64 L using a graduated cylinder to obtain an A-2 solution. The A-2 solution was impregnated with the metal-supported carrier obtained in the step 1, and allowed to stand at room temperature for 20 hours.

Step 3

To the slurry of the alkali-treated ceria carrier obtained in the step 2, 300 g of hydrazine monohydrate was added, and the mixture was slowly stirred, and then allowed to stand at room temperature for 4 hours. After filtering the obtained catalyst, it was transferred to a glass column with a pipe latch, and pure water was passed for 40 hours to be washed. Next, it was dried at 110 ° C for 4 hours under an air flow to obtain a metal-carrying catalyst (A-3).

Step 4

624 g of potassium acetate and 90 g of copper acetate monohydrate were dissolved in pure water, and the mixture was diluted with pure water to a total amount of 3.89 L using a graduated cylinder. The metal-supporting catalyst (A-3) obtained in the step 3 was added thereto to absorb the entire amount. Then, it was dried at 110 ° C for 20 hours under an air flow to obtain a catalyst A for producing allyl acetate. The mass ratios of (a), (b), (c) and (d) are (a): (b): (c): (d) = 1: 0.024: 0.39: 8.5. This mass ratio is based on the mass of the component element in terms of (a), (b) and (c), and based on the mass of the alkali metal salt compound in the case of (d). (e) The supported amount (g) of the (d) alkali metal salt compound per 1 g of the carrier was 0.110 g/g.

Production Example 2 Production of Catalyst B

The production of the catalyst B was carried out except that the amount of potassium acetate in the step 4 was changed from 624 g to 396 g, and the operation of Production Example 1 was repeated. The mass ratios of (a), (b), (c) and (d) are (a): (b): (c): (d) = 1: 0.024: 0.39: 5.4. This mass ratio is based on the mass of the component element in terms of (a), (b) and (c), and based on the mass of the alkali metal salt compound in the case of (d). (e) The supported amount (g) of the (d) alkali metal salt compound per 1 g of the carrier was 0.069 g/g.

<Reference Examples 1 and 2> Performance Evaluation of Catalysts A and B

10.5 mL of each of the catalysts A and B obtained in Production Examples 1 and 2 was uniformly diluted with 31.5 mL of ceramic balls, and then filled in a reaction tube (manufactured by SUS316L, inner diameter: 25 mm). At a reaction temperature of 150 ° C and a reaction pressure of 0.8 MPaG (gauge pressure), a gas mixture of propylene: oxygen: acetic acid: water = 35:6:8:23 (volume ratio) was introduced at a space velocity of 2070 h ^-1 . Gas, and propylene, oxygen and acetic acid form allyl acetate. The analysis of the reactants was carried out 200 hours after the start of the reaction.

As a method of analyzing the reactants, a method of cooling the entire amount of the outlet gas passing through the catalyst packed bed, recovering the total amount of the condensed reaction liquid, and performing analysis by gas chromatography is employed. For the uncondensed gas, the total amount of uncondensed gas flowing out during the sampling time was measured, and a part of it was taken out and analyzed by gas chromatography.

The analysis of the condensed reaction liquid was carried out by using the GC-14B manufactured by Shimadzu Corporation and the FID detector and the capillary column TC-WAX (length 30 m, inner diameter 0.25 mm, film thickness 0.25 μm), and analyzed according to the internal standard method.

The analysis of the non-condensed gas was performed by GC-14B manufactured by Shimadzu Corporation (gas meter gas chromatograph MGS-4, with a 1 mL metering tube), using a TCD detector (He carrying gas, current value 100 mA) ), filled column MS-5A IS (3mm ×3m, 60/80 mesh) and Unibeads (3mm ×3m, 60/80 mesh), using the absolute calibration line method for analysis.

The activity of the catalyst was calculated by the mass (spatial time yield: STY, unit: g/L-cat‧hr) of allyl acetate produced per unit of touch media (L) at one time.

The selectivity of allyl acetate was determined according to the following calculation formula.

Allyl acetate selectivity (propylene standard) (%) = [allyl acetate production (mol) / propylene consumption (mol)] × 100

The amount of potassium acetate in the catalyst is obtained by pulverizing the catalyst to form a uniform powder, and then forming it, and using X-ray analysis (XRF), the content of K (potassium) atoms by absolute absolute line method (% by mass) ) to quantify.

The results of Reference Examples 1 and 2 are shown in Table 1. From the evaluation after 200 hours from the start of the reaction, it was found that the activity (STY) of the catalyst A of Reference Example 1 was higher than that of the catalyst B of Reference Example 2. This means that in the production of allyl acetate, a higher amount of potassium acetate is used to exhibit a higher catalytic activity.

<Example 1>

In the reaction tube having an inner diameter of 34 mm, the inert ball was sequentially placed on the reaction gas inlet side from the reaction gas inlet side to the outlet side, and the layer length was 0.8 m on the upstream side of the catalyst, and the potassium acetate supported amount was large and active. The higher catalyst A was filled to a layer length of 3.3 m, and the catalyst B having a lower potassium acetate loading and lower activity was filled into a layer length of 2.2 m. The raw material gas having the composition shown in Table 2 at a space velocity of 2000 h ^-1 was continuously subjected to a reaction at a reaction temperature of 160 ° C and a reaction pressure of 0.75 MPaG (gauge pressure) for 8,000 hours. After completion of the reaction, the catalyst was extracted so as to be divided into 3:2 from the reaction gas inlet side, and the reaction tube inlet side was the catalyst C, and the reaction tube outlet side was the catalyst D. Fig. 1A shows the filling position of the catalyst of the first embodiment. At the start of the reaction, the carrier (a) of the catalyst A (inlet side) has a supported amount (g) of (d) an alkali metal salt compound (potassium acetate) of 0.1099 g/g and a catalyst B (outlet side). The carrier (g) of the (e) alkali metal salt compound (potassium acetate) per 1 g of the carrier (g) was 0.069 g/g, and the ratio of the potassium acetate supported amount was 1.59 (=0.1099/0.069). The evaluation conditions for the catalysts C and D described later were evaluated after 8000 hours. The results of Example 1 (all) are shown in Table 4.

<Comparative Example 1>

The same reaction as in Example 1 was carried out except that the catalyst to be filled was all the catalyst A and the layer length of the catalyst A was filled to 5.5 m. After completion of the reaction, the catalyst was extracted so as to be divided into 3:2 from the inlet side of the reaction direction, and the catalyst inlet side was the catalyst E and the reactor outlet side was the catalyst F. Fig. 1B shows the filling position of the catalyst of Comparative Example 1. The results are shown in Table 4.

<Comparative Example 2>

The same reaction as in Example 1 was carried out except that the catalyst B was packed in a layer length of 3.3 m from the reaction gas inlet side and the catalyst A was filled to a layer length of 2.2 m. After completion of the reaction, the catalyst was extracted so as to be divided into 3:2 from the inlet side of the reaction direction, and the reactor inlet side was the catalyst G and the reactor outlet side was the catalyst H. Fig. 1C shows the filling position of the catalyst of Comparative Example 2. The results are shown in Table 4.

<Performance evaluation of catalyst C~H>

10.5 mL of each of the catalysts C to H obtained in Example 1 and Comparative Examples 1 and 2 was uniformly diluted with 31.5 mL of ceramic balls, and then filled in a reaction tube (manufactured by SUS316L, inner diameter: 25 mm). The raw material gas having the composition shown in Table 3 at a space velocity of 2070 h ^-1 was subjected to an oxidation reaction for 4 hours under the conditions of a reaction temperature of 160 ° C and a reaction pressure of 0.8 MPaG (gauge pressure). The results are shown in Table 4.

As is clear from Table 4, in the first embodiment, compared with Comparative Example 1 in which the catalyst was uniformly filled in the reaction tube and Comparative Example 2 in which the amount of potassium acetate was loaded, the entire acetene was reacted after 8000 hours of reaction. The propyl ester STY was large, and the catalyst performance of the entire reaction tube was small from the initial stage of the reaction (200 hours). Further, in the catalyst D of Example 1, the amount of potassium acetate supported was smaller than that of the catalyst F of Comparative Example 1, and it was found that the activity of allyl acetate was high. Therefore, it can be seen that the reaction is carried out in such a manner that the amount of potassium acetate supported by the catalyst is sequentially lowered from the inlet side to the outlet side of the reactor as compared with the case where the catalyst of the same specification is uniformly filled. The reaction is carried out by a catalyst, and in the reaction tube, the distribution of potassium acetate in the flow direction of the material gas can be controlled to be more uniform, and the decrease in the activity of the catalyst activity can be suppressed.

[Industrial availability]

The present invention for providing a method for producing allyl acetate which improves the life of a catalyst is industrially useful because it can be used for efficient production of allyl acetate.

Claims (7)

A method for producing allyl acetate, characterized by filling a fourth periodic metal compound having at least one element selected from the group consisting of (a) palladium, (b) gold, and (c) selected from the group consisting of copper, nickel, zinc, and cobalt And (d) an alkali metal salt compound and (e) a fixed bed tube type reactor in which a catalyst for producing allyl acetate is used to supply propylene, oxygen, and acetic acid as a raw material gas, and acetonitrile is produced by a vapor phase contact oxidation reaction. In the method of the propyl ester, in the reaction tube of the fixed-bed tubular reactor, two or more catalyst layers containing the catalyst for producing the allyl allylate containing (d) the amount of the alkali metal salt compound are along The flow direction of the material gas is arranged such that the amount of the (d) alkali metal salt compound supported on the (e) carrier is sequentially decreased from the inlet side to the outlet side of the fixed bed tube type reactor, wherein the reaction tube is the most In the catalyst layer on the inlet side, (e) the carrier (g) of the (d) alkali metal salt compound per carrier (g) is the most in the catalyst layer on the outlet side (e) per 1 g of the carrier (d) The amount of the alkali metal salt compound supported (g) is 1.2 to 3.0 times. The method for producing allyl acetate according to claim 1, wherein the reaction tube is a straight tube, and the catalyst layer is two layers, and the catalyst layer on the inlet side of the reaction tube and the catalyst layer on the outlet side are in a raw material gas. The length ratio of the flow direction is 4:1 to 1:4. A method for producing allyl acetate according to claim 1 or 2, wherein the fixed bed tubular reactor is of a multitubular type. The method for producing allyl acetate according to claim 1 or 2, wherein the (d) alkali metal salt compound is at least one selected from the group consisting of potassium acetate, sodium acetate and cesium acetate. A process for producing allyl acetate according to claim 1 or 2, wherein (c) the fourth cycle metal compound is a compound having copper or zinc. A process for producing allyl acetate according to claim 1 or 2, wherein (c) the metal compound of the fourth cycle is copper acetate. The method for producing allyl acetate according to claim 1 or 2, wherein in the catalyst layer, the (a) palladium, (b) gold, (c) of the catalyst for producing allyl acetate The mass ratio of the fourth cycle metal compound and (d) alkali metal salt compound is (a): (b): (c): (d) = 1: 0.00125 to 22.5: 0.02 to 90: 0.2 to 450.