JP7314712B2 - Method for producing catalyst for producing allyl acetate - Google Patents

Description

TECHNICAL FIELD The present disclosure relates to a method for producing a catalyst used in producing allyl acetate from propylene, oxygen and acetic acid by vapor phase catalytic oxidation. In particular, the present invention relates to a catalyst used in the production of allyl acetate using propylene, oxygen and acetic acid as raw materials, which comprises a fourth period metal compound containing at least one element selected from the group consisting of (a) palladium, (b) gold, (c) copper, nickel, zinc and cobalt as catalyst components, and (d) an alkali metal salt compound supported on (e) a carrier, the catalyst, and a method for producing allyl acetate using the catalyst.

Allyl acetate is one of important industrial raw materials used as a raw material for manufacturing solvents, allyl alcohol, and the like.

Methods for producing allyl acetate include a method using propylene, acetic acid and oxygen as raw materials and using a gas phase reaction or a liquid phase reaction. As a catalyst used for this reaction, a catalyst comprising palladium as a main catalyst component and an alkali metal or alkaline earth metal compound as a co-catalyst supported on a carrier is known and widely used. For example, Japanese Patent Application Laid-Open No. 2-91045 (Patent Document 1) describes a method for producing allyl acetate using a catalyst in which palladium, potassium acetate and copper are supported on a carrier.

Furthermore, other catalyst components have also been studied. For example, Japanese Patent Application Laid-Open No. 52-153908 (Patent Document 2) describes a method for producing allyl acetate using a catalyst whose activity reduction is suppressed by adding molybdenum in addition to palladium, potassium acetate and copper.

In addition, although the reaction is different from that of allyl acetate, for example, Japanese National Publication of International Patent Application No. 2003-525723 (Patent Document 3) describes a method for producing a vinyl acetate production catalyst in which, in the production of vinyl acetate using ethylene, oxygen and acetic acid as starting materials, palladium is supported in the first step, gold is supported in the second step, and copper (II) acetate and potassium acetate are supported in the third step after reduction treatment, thereby suppressing the production of carbon dioxide.

Catalyst technology for vinyl acetate production has been established for a long time, and attempts have been made to apply the vinyl acetate production catalyst technology to allyl acetate production catalyst technology. 33, No. 1 (1991), pp. 28-32 (Non-Patent Document 1).

JP-A-2-91045 JP-A-52-153908 Japanese Patent Publication No. 2003-525723

"Catalyst", Vol. 33, No. 1 (1991), pp. 28-32

An object of the present invention is to provide a highly active catalyst for producing allyl acetate.

The present inventors have made intensive studies to solve the above problems. As a result, it was found that a catalyst for allyl acetate production with improved activity can be obtained by adding a chloride to control the rate of conversion of the palladium-containing compound and the gold-containing compound into oxides or hydroxides in the step of supporting the palladium-containing compound and the gold-containing compound on the support.
That is, the present disclosure includes the following [1] to [9].

[1]
A method for producing a catalyst for producing allyl acetate comprising the following steps in this order: (a) palladium, (b) gold, (c) a fourth period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt, (d) an alkali metal salt compound and (e) a support.
Step 1. A step of preparing a homogeneous solution of a palladium-containing compound, a gold-containing compound, and a chloride of (f) a monovalent cation in an amount of 1.0 to 17.0 mol per 1 mol of palladium atom, and (e) contacting it with a support to support the palladium-containing compound and the gold-containing compound on the support. (g) contacting and impregnating the carrier obtained in step 1 with an alkaline liquid; Step 4. subjecting the carrier obtained in step 2 to reduction treatment. A step of supporting (c) a fourth period metal compound having at least one element selected from the group consisting of copper, nickel, zinc and cobalt and (d) an alkali metal salt compound on the support obtained in step 3 [2]
(f) The method for producing a catalyst for producing allyl acetate according to [1], wherein the monovalent cation chloride is an alkali metal chloride.
[3]
(f) The method for producing a catalyst for producing allyl acetate according to [1], wherein the monovalent cation chloride is sodium chloride.
[4]
(c) The method for producing a catalyst for producing allyl acetate according to any one of [1] to [3], wherein the fourth period metal compound is a compound containing copper or zinc.
[5]
(c) The method for producing a catalyst for producing allyl acetate according to any one of [1] to [3], wherein the fourth period metal compound is copper acetate.
[6]
(d) The method for producing a catalyst for producing allyl acetate according to any one of [1] to [5], wherein the alkali metal salt compound is at least one selected from the group consisting of potassium acetate, sodium acetate and cesium acetate.
[7]
The method for producing a catalyst for producing allyl acetate according to any one of [1] to [6], wherein (b) the amount of gold is 1.7 to 14 parts by mass with respect to 100 parts by mass of (a) palladium.
[8]
A method for producing allyl acetate from propylene, oxygen and acetic acid as raw materials, characterized by using a catalyst produced by the method according to any one of [1] to [7].
[9]
A catalyst produced by the method according to any one of [1] to [7], wherein the mass ratio of (a) palladium, (b) gold, (c) a 4th period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt, and (d) an alkali metal salt compound is 1:0.00125-22.5:0.02-90:0.2-450. Catalyst for allyl production.

According to the method for producing a catalyst for producing allyl acetate of the present disclosure, a supported catalyst with improved catalytic activity can be obtained. As a result, the use of this catalyst makes it possible to reduce the production cost of allyl acetate and to produce allyl acetate efficiently.

4 is a diagram showing the relationship between the molar ratio of sodium chloride to palladium and allyl acetate STY in Examples 1 and 2 and Comparative Examples 1 and 2. FIG.

Embodiments of the present invention will be described below, but it should be understood that the present invention is not limited to only these embodiments, and that various applications are possible within the spirit and scope of implementation.

<Catalyst manufacturing process>
The catalyst for producing allyl acetate of one embodiment comprises (a) palladium, (b) gold, (c) a 4th period metal compound 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 support, and can be produced by a method comprising the following steps in this order. In addition, components other than the above components and steps other than the following steps may be included as necessary.
Step 1. A step of preparing a homogeneous solution of a palladium-containing compound, a gold-containing compound, and a chloride of a monovalent cation (f) at 1.0 to 17.0 mol per 1 mol of palladium atoms, and (e) contacting it with a carrier to support the palladium-containing compound and the gold-containing compound on the carrier. (g) contacting and impregnating the carrier obtained in step 1 with an alkaline liquid; Step 4. subjecting the carrier obtained in step 2 to reduction treatment. Step of supporting (c) a fourth period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt and (d) an alkali metal salt compound on the support obtained in step 3.

These components and steps are described below.

(a) Palladium (a) Palladium may have any valence, but is preferably metallic palladium. "Metal palladium" in the present disclosure has a valence of zero. Metallic palladium can usually be obtained by reducing a divalent or tetravalent palladium ion with a reducing agent such as hydrazine or hydrogen. In this case, not all palladium is in the metallic state.

The compound containing palladium is not particularly limited, and metallic palladium or a palladium precursor convertible to metallic palladium can be used. In this disclosure, palladium metal and palladium precursors are collectively referred to as "palladium sources." Examples of palladium precursors include palladium chloride, palladium nitrate, palladium sulfate, sodium chloropalladate, potassium chloropalladate, barium chloropalladate, palladium acetate, and the like. Sodium chloropalladate is preferably used. A single compound may be used as the palladium precursor, or a plurality of types of compounds may be used in combination.

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

(b) Gold (b) Gold is supported on the carrier in the form of a gold-containing compound, but it is preferred that substantially all of the gold be ultimately metallic gold. “Metal gold” in the present disclosure has a valence of zero. Metallic gold can usually be obtained by reducing monovalent or trivalent gold ions using a reducing agent such as hydrazine or hydrogen. In this case, not all gold may be in the metallic state.

The compound containing gold is not particularly limited, and metallic gold or a gold precursor convertible to metallic gold can be used. In this disclosure, metallic gold and gold precursors are collectively referred to as "gold sources." Examples of gold precursors include chloroauric acid, sodium chloroaurate, potassium chloroaurate, and the like. Preferably, chloroauric acid or sodium chloroaurate is used. As the gold precursor, a single compound may be used, or multiple types of compounds may be used in combination.

The mass ratio of (b) gold to (e) the support in the catalyst for producing allyl acetate is preferably (b):(e) = 1:40 to 1:65000, more preferably (b):(e) = 1:550 to 1:32000, still more preferably (b):(e) = 1:750 to 1:10000. This ratio is defined as the ratio of the mass of elemental gold to the mass of the support.

The amount of (b) gold in the catalyst for producing allyl acetate is preferably 1.7 to 14 parts by mass, more preferably 2 to 12 parts by mass, and still more preferably 2 to 3.5 parts by mass with respect to 100 parts by mass of palladium. Parts by weight of gold and palladium are based on the weight of the respective element. With such an amount of gold, it is possible to obtain a good balance between maintaining the activity of the catalyst in the allyl acetate production reaction and allyl acetate selectivity.

(c) a fourth period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt (sometimes simply referred to as "(c) fourth period metal compound");
(c) As the fourth period metal compound, soluble salts such as nitrates, carbonates, sulfates, organic acid salts, and halides of at least one element selected from the group consisting of copper, nickel, zinc, and cobalt can be used. The (c) 4th period metal compound is preferably a compound containing copper or zinc, since the catalytic activity can be further enhanced. Acetate etc. are mentioned as an organic acid salt. In general, compounds that are readily available and water soluble are preferred. Preferred compounds include copper nitrate, copper acetate, nickel nitrate, nickel acetate, zinc nitrate, zinc acetate, cobalt nitrate, cobalt acetate, and the like. Among these, copper acetate is most preferable from the viewpoint of the stability of the raw material and the availability. (c) As the fourth period metal compound, a single compound may be used, or a plurality of types of compounds may be used in combination.

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

(d) Alkali Metal Salt Compounds (d) Alkali metal salt compounds include hydroxides, acetates, nitrates, and hydrogen carbonates of lithium, sodium, potassium, rubidium, cesium, and the like. 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 types of compounds may be used in combination.

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

(e) Carrier (e) The carrier is not particularly limited, and porous substances generally used as carriers for catalysts can be used. Examples of preferred supports include silica, alumina, silica-alumina, diatomaceous earth, montmorillonite, titania and zirconia. More preferably silica is used. When a carrier containing silica as a main component is used, the silica 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 preferably has a specific surface area of 10 to 1000 m ² /g, more preferably 100 to 500 m ² /g, as measured by the BET method. The bulk density of the carrier is preferably in the range of 50-1000 g/L, particularly preferably in the range of 300-500 g/L. The water absorption of the carrier is preferably 0.05 to 3 g-water/g-carrier, particularly preferably in the range of 0.1 to 2 g-water/g-carrier. Regarding 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. When the average pore diameter is 1 nm or more, diffusion of gas can be facilitated. On the other hand, when the pore diameter is 1000 nm or less, the specific surface area of the carrier necessary for obtaining catalytic activity can be ensured.

The water absorption rate of the carrier in the present disclosure refers to numerical values measured according to the following procedure.
1. About 5 g of the carrier is accurately weighed with a balance and placed in a 100 mL beaker. Let the mass at this time be _w1 .
2. About 15 mL of pure water (ion-exchanged water) is added to the beaker so that the carrier is completely covered.
3. Let stand for 30 minutes.
4. The supernatant pure water is removed from the carrier.
5. Remove water adhering to the surface of the carrier by lightly pressing with a paper towel or the like until the surface becomes dull.
6. Accurately weigh the total mass of the carrier and pure water. Let the mass at this time be _w2 .
7. The water absorption of the carrier is calculated from the following formula.
Water absorption (g-water/g-carrier) = (w ₂ -w ₁ )/w ₁
Therefore, the water absorption amount (g) of the carrier is calculated by multiplying the water absorption rate of the carrier (g-water/g-carrier) by the mass (g) of the carrier used.

The shape of the carrier is not particularly limited. Specific examples thereof include powder, spherical, pellet, and the like, but are not limited to these. An optimum shape can be selected according to the reaction type, reactor, etc. used.

Mercury intrusion method and gas adsorption method (BJH method) are widely used to measure the pore size distribution of the carrier. Looking at the pore classification of IUPAC (International Union of Pure and Applied Chemistry), the mercury intrusion method can measure macropores of 50 nm or more and some mesopores of 2 nm to less than 50 nm, and the gas adsorption method can measure mesopores and micropores of 2 nm or less. An appropriate method may be selected according to the size of the pore diameter.

The particle size of the carrier is also not particularly limited. If the carrier is spherical, its particle diameter is preferably in the range of 1-10 mm, more preferably in the range of 2-8 mm. When a gas phase reaction is performed by filling a tubular reactor with a catalyst, if the particle diameter is 1 mm or more, an excessive increase in pressure loss when the gas is circulated can be prevented, and the gas can be effectively circulated. On the other hand, when the particle diameter is 10 mm or less, the reaction gas can be easily diffused into the interior of the catalyst, and the catalytic reaction can proceed effectively.

(f) Monovalent cation chloride The (f) monovalent cation chloride is preferably an alkali metal chloride. That is, chlorides of lithium, sodium, potassium, rubidium, cesium, etc. can be used as chlorides of monovalent cations. Among them, lithium chloride, sodium chloride and potassium chloride are preferred, and sodium chloride is more preferred. As the monovalent cation chloride, a single compound may be used, or a plurality of types of compounds may be used in combination. By using monovalent cation chlorides, the chloride ion concentration in the solution can be varied to control the rate of conversion of the palladium and gold compounds in step 2 to oxides or hydroxides.

The amount of (f) monovalent cation chloride used in step 1 is 1.0 to 17 mol, preferably 2.0 to 15.0 mol, per 1 mol of (a) palladium atom. This ratio is calculated from the charge ratio of the amount of chloride of the monovalent cation used and the amount of palladium used. By setting the amount of chloride of a monovalent cation within the above range, a highly active catalyst for producing allyl acetate can be obtained.

(g) Alkaline liquid The (g) alkaline liquid used in step 2 is not particularly limited, and any alkaline liquid can be used. (g) The alkaline liquid may itself be an alkaline liquid or may be a solution of an alkaline substance. Alkaline substances used as raw materials for the alkaline liquid 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. Preferred alkali metals are lithium, sodium and potassium, and preferred alkaline earth metals are barium and strontium. Particularly preferred alkaline compounds include sodium metasilicate, potassium metasilicate, sodium hydroxide, potassium hydroxide, barium hydroxide and the like. Part or all of the palladium compounds and part or all of the gold compounds can be converted to oxides or hydroxides by contact with an alkaline liquid.

The alkaline substance is suitably used in molar equivalent excess relative to the sum of (a) palladium and (b) gold. For example, the amount of alkaline compound used corresponds to the sum of (a) preferably 1-3 moles, more preferably 1.2-2.5 moles per mole of palladium atom and (b) preferably 2-10 moles, more preferably 3-8 moles per mole of gold atom.

The solvent used for forming the alkaline liquid is not particularly limited, and preferred examples include water, methanol, ethanol and the like. The same solvent as used in step 1 is preferred.

Next, each step will be explained.

Process 1
In this step, a homogeneous solution containing a palladium raw material (metallic palladium or its precursor), a gold raw material (metallic gold or its precursor), and a monovalent cation chloride is prepared, and the obtained homogeneous solution is brought into contact with the carrier to support these raw materials. The state in which these raw materials are supported on the carrier is preferably a so-called "eggshell type". In this case, the method for supporting the homogeneous solution containing the palladium raw material and the gold raw material on the carrier is not particularly limited as long as it is a method that results in obtaining an eggshell-type supported catalyst. The eggshell-type supported catalyst refers to a supported catalyst in which most of the active ingredient (for example, metallic palladium) is distributed on the carrier particles or shaped body on the outer surface of the carrier particles or shaped body. Specific examples of the method for producing the eggshell-type supported catalyst include a method of dissolving a raw material in an appropriate solvent such as water or acetone, or an inorganic or organic acid such as hydrochloric acid, nitric acid, or acetic acid, or a solution thereof, and directly or indirectly supporting the material on the surface of the carrier. Examples of the method for directly supporting include an impregnation method and a spray method. As a method for indirect loading, as will be described later, a uniform solution containing a palladium raw material, a gold raw material, and a monovalent cation chloride is brought into contact with the carrier first to carry these raw materials on the carrier (step 1), and then (g) the palladium raw material and the gold raw material inside are moved to the surface by contact impregnation with an alkaline liquid (step 2), and then a reduction treatment is performed (step 3).

A palladium raw material and a gold raw material can be supported on a carrier by preparing a uniform solution containing a palladium raw material, a gold raw material, and chlorides of monovalent cations, and contacting and impregnating an appropriate amount of the carrier with the solution. More specifically, a palladium raw material, a gold raw material, and a monovalent cation chloride are dissolved in a suitable solvent such as water or acetone, or an inorganic or organic acid such as hydrochloric acid, nitric acid, or acetic acid, or a solution thereof to prepare a uniform solution, and the resulting homogeneous solution is brought into contact with the carrier to obtain the carrier (A). Although the impregnation may be followed by drying, it is preferable to omit the drying step and proceed to step 2 because it is more efficient.

Process 2
This step is a step of contact-impregnating the carrier (A) obtained in step 1 with (g) an alkaline liquid to obtain an impregnated carrier (B). The alkaline substance used in step 2 (g) alkaline liquid can be used as it is if it is a liquid itself, but is preferably supplied in the form of a solution. The alkaline liquid is preferably a solution of water, alcohol, or a mixed solvent of water and alcohol. The contact conditions between the carrier (A) and the alkaline liquid are not particularly limited, but 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 0.5 hours or more, sufficient performance can be obtained, while if it is 100 hours or less, unnecessary damage to the carrier can be prevented.

Although the contact temperature is not particularly limited, it is preferably in the range of 10 to 80°C, more preferably in the range of 20 to 60°C. Sufficient conversion rates can be obtained by contacting at 10° C. or higher. On the other hand, contacting at 80° C. or less can suppress aggregation of palladium or gold.

Process 3
This step is a step of subjecting the impregnated carrier (B) obtained in step 2 to a reduction treatment. Either liquid phase reduction or vapor phase reduction can be used as the reduction method. The metal-supported carrier obtained in this step is referred to as a metal-supported carrier (C).

Liquid phase reduction can be carried out either non-aqueously or aqueously using alcohols or hydrocarbons. Carboxylic acids and their salts, aldehydes, hydrogen peroxide, sugars, polyhydric phenols, boron compounds, amines, hydrazines, and the like can be used as reducing agents. Examples of carboxylic acids and salts thereof include oxalic acid, potassium oxalate, formic acid, potassium formate, potassium citrate, ammonium citrate, and the like. Examples of aldehydes include formaldehyde, acetaldehyde, and the like. Glucose etc. are mentioned as sugars. Examples of polyhydric phenols include hydroquinone and the like. Examples of boron compounds include diborane, sodium borohydride, and the like. Among these, hydrazine, formaldehyde, acetaldehyde, hydroquinone, sodium borohydride, or potassium citrate are preferably used, and hydrazine is more preferably used.

When the liquid phase reduction is performed, the temperature is not particularly limited, but the liquidus temperature is preferably in the range of 0 to 200°C, more preferably in the range of 10 to 100°C. When the temperature is 0°C or higher, a sufficient reduction rate can be obtained. On the other hand, when the temperature is 200° C. or lower, aggregation of palladium or gold can be suppressed. The reduction time is not particularly limited, but the reduction time is preferably in the range of 0.5 to 24 hours, more preferably in the range of 1 to 10 hours. When the time is 0.5 hours or longer, the reduction can be sufficiently advanced. On the other hand, if it is 24 hours or less, aggregation of palladium or gold can be suppressed.

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

When gas phase reduction is carried out, the temperature is not particularly limited, but the impregnated support (B) is preferably heated to a range of 30 to 350°C, more preferably to a range of 100 to 300°C. When the temperature is 30°C or higher, a sufficient reduction rate can be obtained. On the other hand, when the temperature is 300° C. or lower, aggregation of palladium or gold can be suppressed. The reduction time is not particularly limited, but the reduction time is preferably in the range of 0.5 to 24 hours, more preferably in the range of 1 to 10 hours. When the time is 0.5 hours or longer, the reduction can be sufficiently advanced. On the other hand, if it is 24 hours or less, aggregation of palladium or gold can be suppressed.

The treatment pressure of the gas phase reduction is not particularly limited, but 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.

The supply rate of the reducing agent in gas phase reduction is preferably in the range of space velocity (hereinafter referred to as SV) of 10 to 15,000 hr ^-1 , particularly preferably in the range of 100 to 8,000 hr ^-1 under standard conditions.

Gas phase reduction can be carried out with a variety of reducing substance concentrations, and if desired, an inert gas may be added as a diluent. Examples of inert gases include helium, argon, and nitrogen gas. Reduction may be performed in the presence of hydrogen, propylene, or the like in the presence of vaporized water.

The reduced carrier is preferably washed with water. By this operation, the (f) monovalent cation chloride used in step 1 and no longer needed can also be removed. Washing may be performed in a flow system or in a batch system. The washing temperature is preferably in the range of 5 to 200°C, more preferably in the range of 15 to 80°C. There is no particular limitation on the washing time. It is preferred to select conditions sufficient to effect removal of any remaining undesirable impurities. After washing, it may be dried by heating if necessary.

Step 4
This step is a step of supporting (c) a fourth period metal compound and (d) an alkali metal salt compound on the metal-supported carrier (C) obtained in step 3.

The metal-carrying carrier (C) is brought into contact with a solution containing the necessary amounts of (c) the 4th period metal compound and (d) the alkali metal salt compound and having a mass of 0.9 to 1.0 times the water absorption amount of the carrier, and dried to carry each compound. The solvent at this time is not particularly limited. Various solvents can be used that are capable of dissolving the alkali metal salt compound used in a solution having a mass of 0.9 to 1.0 times the water absorption of the carrier. The solvent is preferably water. The supported amount of the alkali metal salt compound can be adjusted by changing the concentration of this solution. There are no particular restrictions on drying temperature and time.

<Catalyst component composition>
The mass ratio of (a) palladium, (b) gold, (c) the fourth period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt, and (d) the alkali metal salt compound in the catalyst for producing allyl acetate is preferably (a):(b):(c):(d)=1:0.00125-22.5:0.02-90:0.2-450, more preferably (a):(b):( c):(d)=1:0.0025-0.14:0.04-50:0.4-250, particularly preferably (a):(b):(c):(d)=1:0.008-0.1:0.04-50:0.4-250. (a), (b) and (c) are based on the mass of the component elements, and (d) is based on the mass of the alkali metal salt compound.

The supported amount and composition ratio of the metal elements contained in the catalyst for producing allyl acetate can be measured by chemical analysis such as high frequency inductively coupled plasma emission spectrometry (hereinafter abbreviated as “ICP”), fluorescent X-ray analysis (hereinafter abbreviated as “XRF”), and atomic absorption spectrometry.

As an example of the measurement method, a predetermined amount of the catalyst is pulverized in a mortar or the like to obtain a uniform powder, and then the powdered catalyst is added to an acid such as hydrofluoric acid or aqua regia, heated and stirred, and dissolved to form a uniform solution. Next, the solution is diluted with pure water to an appropriate concentration, and the solution is quantitatively analyzed by ICP.

<Production of allyl acetate>
The reaction for producing allyl acetate is preferably carried out in the gas phase using propylene, oxygen and acetic acid as raw materials. The form of the gas phase reaction is not particularly limited, and known methods such as fixed bed and fluidized bed forms can be used. Preferably, it is practically advantageous to adopt a fixed-bed flow reaction in which the above-mentioned catalyst is packed in a reaction tube having corrosion resistance. The reaction formula is as follows.
_CH2 = _CHCH3 + _CH3COOH +1/ _2O2 →
_CH2 = _{CHCH2OCOCH3 + H2O}

The raw material gas contains propylene, oxygen gas and acetic acid, and if necessary, nitrogen gas, carbon dioxide, rare gas, etc. can be used as a diluent.

The raw material gas preferably has a composition in a molar ratio of acetic acid:propylene:oxygen=1:1-12:0.5-2.

In the reaction for producing allyl acetate, the presence of water in the reaction system has a significant effect on the allyl acetate-producing activity of the catalyst and its maintenance. Steam is preferably present in the gas supplied to the reaction in a range of 0.5 to 25% by volume.

In the gas supplied to the reaction, it is preferable to use propylene of high purity, but it may be mixed with lower saturated hydrocarbons such as methane, ethane and propane. Oxygen gas diluted with an inert gas such as nitrogen gas or carbon dioxide gas, for example, can be supplied in the form of air, but when the reaction gas is circulated, it is generally advantageous to use oxygen at a high concentration, preferably 99% by volume or more.

There are no particular restrictions on the reaction temperature. It is preferably in the range of 100 to 300°C, more preferably in the range of 120 to 250°C. It is practically advantageous that the reaction pressure is in the range of 0.0 to 3.0 MPaG (gauge pressure) from the standpoint of equipment, but there is no particular limitation. 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 the range of SV=10 to 15000 hr ^-1 under standard conditions, and particularly preferably in the range of 300 to 8000 hr ^-1 .

EXAMPLES The present invention will be further described below with reference to examples and comparative examples, but the present invention is not limited by these descriptions.

<Example 1 Production of catalyst A>
Using a silica spherical carrier (spherical diameter 5 mm, specific surface area 155 m ² /g, average pore diameter 24 nm, water absorption 0.85 g-water/g-carrier, HSV-D manufactured by Shanghai Haiyuan Chemical Technology Co., Ltd., hereinafter simply referred to as “silica carrier”), production was performed by the following procedure.

Step 1: 30.3 g of a sodium chloropalladate aqueous solution adjusted to have a palladium element content of 19.79% by mass, 1.50 g of a chloroauric acid aqueous solution adjusted to have a gold element content of 10% by mass, and 9.89 g of sodium chloride were mixed and diluted with pure water to 382 mL in a graduated cylinder to obtain an A-1 solution. 1 L of silica carrier (bulk density 473 g/L, water absorption 402 g/L) was added to this, and the A-1 solution was impregnated to absorb the entire amount.

Step 2: 35.6 g of sodium metasilicate nonahydrate was dissolved in pure water, and diluted with pure water to 803 mL in a graduated cylinder to obtain solution A-2. The metal-supported carrier (A-1) obtained in step 1 was impregnated with the A-2 solution and allowed to stand at room temperature (23° C.) for 20 hours.

Step 3: 26.6 g of hydrazine monohydrate was added to the slurry of the alkali-treated silica carrier (A-2) obtained in Step 2, gently stirred, and allowed to stand at room temperature (23° C.) for 4 hours. After filtering the obtained catalyst, it was transferred to a glass column equipped with a stopcock, and purified water was passed through for 40 hours for washing. Then, it was dried at 110° C. for 4 hours under an air stream to obtain a supported metal catalyst (A-3).

Step 4: Pure water was added to 52 g of potassium acetate and 7.5 g of copper acetate monohydrate to dissolve, and diluted to 361 mL with pure water in a graduated cylinder. The metal-supported catalyst (A-3) obtained in step 3 was added to this to absorb the entire amount. Then, it was dried at 110° C. for 4 hours under an air stream to obtain a catalyst A for producing allyl acetate.

<Example 2 Production of catalyst B>
Catalyst B was produced by repeating the operation of Example 1, except that the amount of sodium chloride was changed from 9.89 g to 39.54 g.

<Comparative Example 1 Production of Catalyst C>
Catalyst C was prepared by repeating the procedure of Example 1 without adding sodium chloride.

<Comparative Example 2 Production of Catalyst D>
Catalyst D was produced by repeating the operation of Example 1, except that the amount of sodium chloride was changed from 9.89 g to 79.12 g.

<Performance Evaluation of Examples 1 and 2 and Comparative Examples 1 and 2 Catalysts A to D>
10.5 mL of each of the catalysts A to D obtained in Examples 1 and 2 and Comparative Examples 1 and 2 were uniformly diluted with 31.5 mL ceramic balls, and then filled into a reaction tube (made of SUS316L, inner diameter 25 mm). Under conditions of a reaction temperature of 150° C. and a reaction pressure of 0.75 MPaG (gauge pressure), a mixed gas having a gas composition of propylene:oxygen:acetic acid:water=35:6:8:23 (volume ratio) was introduced at a space velocity of 2070 h ⁻¹ to produce allyl acetate from propylene, oxygen and acetic acid. Analysis of the reaction product was performed after 200 hours had elapsed from the start of the reaction.

As a method for analyzing the reaction product, a method was used in which the total amount of the exit gas that passed through the catalyst packed bed was cooled, the total amount of the condensed reaction liquid was collected, and the reaction product was analyzed by gas chromatography. As for the uncondensed gas, the total amount of uncondensed gas that flowed out during the sampling time was measured, and a part of it was taken out and analyzed by gas chromatography.

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

Analysis of uncondensed gas is performed using Shimadzu Corporation GC-14B (Shimadzu gas chromatograph gas sampler MGS-4, with measuring tube 1 mL), TCD detector (He carrier gas, current value 100 mA), packed column MS-5A IS (3 mmφ × 3 m, 60/80 mesh) and Unibeads (3 mmφ × 3 m, 60/80 mesh), absolute calibration curve. The analysis was performed using the method.

The activity of the catalyst was calculated as the mass of allyl acetate produced per hour per catalyst volume (L) (space-time yield: STY, unit: g/L-cat·hr).
The selectivity of allyl acetate was determined by the following formula.
Allyl acetate selectivity (based on propylene) (%) = [amount of allyl acetate produced (mol)/amount of propylene consumed (mol)] x 100

Table 1 shows the results of Examples 1 and 2 and Comparative Examples 1 and 2. From Table 1, it can be said that the catalysts A and B of Examples 1 and 2 have higher activity than the catalysts C and D of Comparative Examples 1 and 2 and are excellent catalysts.

INDUSTRIAL APPLICABILITY The present invention, which provides a method for producing a catalyst for producing allyl acetate with improved catalytic activity, is industrially useful because it can be used for efficient production of allyl acetate.

Claims (8)

A method for producing a catalyst for producing allyl acetate comprising the following steps in this order: (a) palladium, (b) gold, (c) a fourth period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt, (d) an alkali metal salt compound and (e) a support.
Step 1. A step of preparing a homogeneous solution of a palladium-containing compound, a gold-containing compound, and a chloride of (f) a monovalent cation in an amount of 1.0 to 17.0 mol per 1 mol of palladium atom, and (e) contacting it with a support to support the palladium-containing compound and the gold-containing compound on the support. (g) contacting and impregnating the carrier obtained in step 1 with an alkaline liquid; Step 4. subjecting the carrier obtained in step 2 to reduction treatment. Step of supporting (c) a fourth period metal compound containing at least one element selected from the group consisting of copper, nickel, zinc and cobalt and (d) an alkali metal salt compound on the support obtained in step 3. 2. The method for producing a catalyst for producing allyl acetate according to claim 1, wherein (f) the monovalent cation chloride is an alkali metal chloride. 2. The method for producing a catalyst for producing allyl acetate according to claim 1, wherein (f) the monovalent cation chloride is sodium chloride. (c) The method for producing a catalyst for producing allyl acetate according to any one of claims 1 to 3, wherein the fourth period metal compound is a compound containing copper or zinc. (c) The method for producing a catalyst for producing allyl acetate according to any one of claims 1 to 3, wherein the fourth period metal compound is copper acetate. (d) The method for producing a catalyst for producing allyl acetate according to any one of claims 1 to 5, wherein the alkali metal salt compound is at least one selected from the group consisting of potassium acetate, sodium acetate and cesium acetate. The method for producing a catalyst for producing allyl acetate according to any one of claims 1 to 6, wherein the amount of (b) gold is 1.7 to 14 parts by mass with respect to 100 parts by mass of (a) palladium. A method for producing allyl acetate from propylene, oxygen and acetic acid as raw materials, characterized by using a catalyst produced by the method according to any one of claims 1 to 7.

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