JPH03275141A - Preparation of catalyst for production of unsaturated ester - Google Patents

Abstract

PURPOSE:To obtain a Pd-contg. catalyst having high activity and a long service life by treating a metallic component to be supported and a carrier component with an aq. tartaric acid soln. contg. hydrogen halide at a specified concn. CONSTITUTION:A metallic component to be supported such as a Pd compd. and a carrier component such as silica are treated with an aq. tartaric acid soln. contg. 0.1-10wt.% hydrogen halide. The Pd-contg. component is supported on the carrier and subjected to reduction treatment in a flow of a reducing gas such as hydrogen or a gaseous org. compd. having reducing power optionally after drying and calcining to obtain a Pd-contg. catalyst for production of unsatd. ester from olefins, carboxylic acid and molecular oxygen. This catalyst has a sufficiently prolonged service life, superior catalytic activity and high performance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for preparing a catalyst for producing an unsaturated ester,
More specifically, it is used in the production of unsaturated esters (unsaturated alcohol diesters of dicarboxylic acids) through the oxidative acyloxylation reaction of olefins, especially dienes, with carboxylic acids, and has significantly improved performance such as activity and lifespan. The present invention relates to a method for preparing palladium-based catalysts.

[Prior art] Unsaturated esters such as carboxylic acid diesters (unsaturated esters) of unsaturated glycols such as diacetoxybutene are
It is industrially useful as a solvent, a chemical product such as 7mer, or an intermediate raw material thereof.

Among unsaturated esters, butyne diol diesters such as diacetoxybutene are particularly useful, and by hydrogenation and hydrolysis, they can be used as raw materials suitable for the production of, for example, pyrrolidone and tetrahydrofuran, or as PBT (polybutene). However, 1,4-butanediol, which is useful as a monomer and an organic solvent for producing tstyrene terephthalate, can be used as a butanediol. Various methods are being considered for producing this butanediol, especially using phtadiene as a raw material.
The method via the above-mentioned butyne diol diester is important.

Conventionally, methods for producing these unsaturated esters include a method in which olefins such as dienes are reacted with an organic carboxylic acid and molecular oxygen in the presence of a suitable catalyst, that is, an oxidative acyloxylation reaction of olefins. Various methods have been proposed.

For example, there is a method for producing various unsaturated esters (carboxylic acid diesters of unsaturated glycols) including butyne diol diesters such as diacetoxybutene by using olefins as raw materials for conjugated dienes such as butadiene.

Various catalysts have been proposed for the production of unsaturated esters such as unsaturated esters through the oxidative acyloxylation reaction of these olefins. Supported catalysts, which can also be applied to

Depending on the composition and preparation method of this supported palladium-based catalyst, many unsaturated ester manufacturing techniques have been proposed. bismuth,
A method using a catalyst containing vanadium or the like as a co-catalyst component (Japanese Patent Publication No. 5212686, Japanese Patent Publication No. 52-28776, Japanese Patent Publication No. 15488-1988), and a method in which an alkali metal is further added to this catalyst system as an activity promoting component. There is a method using a catalyst to which a carboxylic acid salt or an alkali metal halide is added (Japanese Patent Publication No. 5315490).

In general, there are various methods for preparing supported catalysts depending on the supporting operation, treatment method, etc.

Among these many preparation methods, a metal component to be supported is dissolved in an appropriate solvent, an appropriate carrier is brought into contact with the solution, and this is removed by distillation of the solvent, etc., to form a predetermined composition on the carrier. Wet supporting methods using a so-called solvent (solution), such as an impregnation method, an adsorption method, and a wet mixing method, for supporting metal components are preferably applied.

The method for preparing the supported palladium-based catalyst used in the conventional oxidative acyloxylation reaction uses a palladium compound as the main component as a metal component, and uses an oxide such as silica or alumina or activated carbon as a carrier. Wet support methods such as the above-mentioned impregnating method have been applied using a hydrogen halide solution such as hydrochloric acid, a nitric acid aqueous solution, an organic solvent, or an organic acid aqueous solution such as tartaric acid as a solvent. In each case, the various solvents mentioned above are used alone.

[Problems to be Solved by the Invention] As mentioned above, various supported palladium-based catalysts are used in the method for producing unsaturated esters by the oxidative acyloxylation reaction of olefins with carboxylic acids. However, there is a problem in that the performance of catalysts such as activity and lifespan is not necessarily industrially satisfactory.In particular, in the production of unsaturated esters from conjugated dienes by the gas phase flow method, catalyst performance, especially lifespan, is not always satisfactory. A major improvement was expected.

The present invention has been made in view of the above circumstances.

An object of the present invention is to solve the above-mentioned problems, and to improve the production of unsaturated esters by the oxidative acyloxylation reaction of olefins with carboxylic acids (particularly production by gas phase flow method), compared to the conventional method using a catalyst. We also developed a method for preparing supported palladium-based catalysts with sufficiently improved performance such as activity and lifetime, which makes it possible to industrially advantageously produce unsaturated esters from olefins (especially unsaturated esters from conjugated dienes). It is about providing.

[Means for Solving the Problems] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have found that, basically, the conventional method of supporting palladium on a palladium-containing metal support and then subjecting it to reduction treatment. Even if the wet supporting method is used, a supported palladium-based catalyst is prepared using a specific method of treating the metal component to be supported and the carrier component with an aqueous tartaric acid solution containing a specific concentration of hydrogen halide. Then, surprisingly, olefins,
In particular, for oxidative acyloxylation reactions of conjugated dienes using gas-phase flow methods, etc., the catalyst life is greatly improved, and the space-time yield of the target unsaturated ester, especially the unsaturated ester from the conjugated diene, is also improved. Based on this knowledge, we have completed the present invention.

That is, the present invention provides a method for preparing a palladium-based catalyst for producing an unsaturated ester from olefins, a carboxylic acid, and molecular oxygen, in which the supported metal component and carrier component are halogenated in an amount of 0.1 to 10% by weight. The present invention relates to a method for preparing a catalyst for producing an unsaturated ester, which comprises treating with an aqueous tartaric acid solution containing hydrogen chloride, followed by reduction treatment.

The method for preparing the catalyst of the present invention includes treating the metal component to be supported and the carrier component with an aqueous tartaric acid solution containing 0.1 to 10% by weight of hydrogen halide to support the metal component on the carrier component,
There are no particular restrictions other than the point that a reduction treatment is performed thereafter, and any method commonly used for preparing conventional palladium-based catalysts for producing unsaturated esters as well as general supported metal-based catalysts can be used.

Here, the metal component treated with the tartaric acid aqueous solution containing hydrogen halide contains at least one type of palladium compound.

For example, a palladium compound, or a metal component consisting of a palladium compound and a metal compound as another catalyst component used as desired, is dissolved in an aqueous tartaric acid solution containing 0.1 to 10% by weight of hydrogen halide, and then added to the solution. After immersing a predetermined carrier, the solvent is evaporated and removed, the palladium-containing component is supported on the carrier, and then, if necessary, dried and fired,
Thereafter, a reduction treatment is performed by reducing in a stream of a reducing gas such as hydrogen or an organic compound having sufficient reducing power, or by using a reducing agent such as hydrazine or formaldehyde, and then, if necessary, an alkali metal The palladium-based catalyst of the present invention can be easily prepared by a method of supporting an arbitrary component such as a carboxylate salt.

The preparation method according to the above method is an example of a preferred embodiment of the catalyst preparation method of the present invention, and of course, various modifications are possible.

For example, in addition to the above-mentioned impregnation method, wet adsorption method, wet mixing method, and its precursor as a carrier component (for example, those that decompose into carriers such as oxides in the calcination stage or reduction treatment stage)
Various supporting methods can be employed, such as a wet kneading method with the hydrogen halide, or a method that combines these methods. Various methods can be used, such as a method in which the metal compound is immersed in a tartaric acid-containing aqueous solution and the palladium-containing supported metal compound is added thereto, and a method in which the order of contact of each preparation component is appropriately changed.

In the method for preparing the catalyst of the present invention, after the predetermined metal component is supported on a carrier component, this is usually dried as appropriate.
It is preferable to bake it.

The drying and calcination conditions are not particularly limited, and, for example, conditions used in conventional methods for preparing supported palladium-based catalysts used in this field can be appropriately employed.

The conditions for the reduction treatment cannot be unconditionally defined because they vary depending on the carrier used and other conditions such as the type and composition of the metal component. Conditions for reducing to metallic palladium can be appropriately adopted.

As the carrier component used in the preparation method of the present invention, any carrier that is normally used as a catalyst carrier or its precursor can be used.

Typical examples of the carrier include oxide carriers such as silica, alumina, silica-alumina, titania, zirconia, matanesia, and zeolite, and activated carbon. Among these, silica, titania, etc. are particularly preferred.

Note that these carrier components may be used alone or in combination of two or more as a mixture.

In the preparation method of the present invention, the concentration of tartaric acid in the tartaric acid aqueous solution used for catalyst preparation is usually 0.1
It is appropriate to select the amount in the range of 1 to 60% by weight, preferably 1 to 40% by weight.

If the concentration of tartaric acid is too low or too high, the catalyst life and catalyst activity may not be sufficiently improved, and the objects of the present invention may not be fully achieved.

The hydrogen halide contained in the tartaric acid aqueous solution is
There are no particular limitations, such as hydrogen fluoride (hydrofluoric acid),
Mention may be made of hydrogen chloride (hydrochloric acid), hydrogen bromide (bromic acid), hydrogen iodide (hydriodic acid) and mixtures thereof. Among these, hydrogen chloride (hydrochloric acid) is particularly preferred.

Note that these may be used alone or in combination of two or more.

The concentration of the hydrogen halide in the tartaric acid aqueous solution can be varied as appropriate in the range of 0.1 to 10% by weight as described above, or in particular in the range of 0.2 to 5% by weight. is preferred.

The concentration of hydrogen halide in this tartaric acid aqueous solution was set to 0.
．． If the content is less than 1% by weight or greater than 10% by weight, the improvement in catalyst life may be insufficient or the improvement in catalyst activity may not be achieved, and the purpose of the present invention cannot be fully achieved. I can't do anything.

In the catalyst preparation method of the present invention, the palladium compounds used for preparing the supported palladium-based catalyst include:
Examples include, but are not limited to, palladium halides such as palladium chloride, palladium chloride or their salts, palladium nitrate, palladium sulfate,
Organic acid palladium, various palladium complexes, etc. may be used alone, or two or more types may be used in combination as a mixture.

As other metal components that can be used in combination with the palladium compound if desired, any metal component can be added as long as it does not impede the object of the present invention.

Examples of the above-mentioned metal components include metal components known as co-catalyst components that are combined with ordinary palladium-based catalysts, and preferred representative examples include antimony, bismuth, tellurium, vanadium, etc. I can list many things. In addition, these are
As desired, one type may be used alone or two or more types may be used in combination.

In addition, other metal components such as these promoter components may be in the form of various compounds, such as halides, inorganic acid salts, organic acid salts, oxides, hydroxides, or mixtures or composite compounds thereof. Available in

Among these, for antimony, antimony trioxide is particularly preferably used, and for vanadium, ammonium metavanadate is usually particularly preferably used.

In the preparation method of the present invention, an activity-promoting component may be used as a catalyst component in addition to the above, if desired.

As this activity promoting component, any substance can be used as long as it can improve the catalytic activity, and various known substances can be used alone or in combination as a mixture of two or more. It comes.

Representative examples of this activity-promoting component include alkali metal carboxylates and alkali metal halides.

Examples of this alkali metal carboxylate include:
Mention may be made of lithium, sodium, potassium, rubidium or cesium acetates.

The alkali metal halides include lithium,
Mention may be made of the fluoride, chloride, bromide or iodide of sodium, potassium, rubidium or cesium.

Note that these may be used alone or in combination of two or more, as desired.

Furthermore, for example, a method of combining cesium acetate and cesium chloride can also be suitably employed.

These activity-promoting components can be added by various methods, or by impregnating an aqueous solution of the activity-promoting component with a supported catalyst such as a metal component such as palladium, and then removing water by evaporation. Accordingly, it is added and supported by performing post-treatment such as drying.

In the catalyst preparation method of the present invention, the palladium concentration in the supported palladium-based catalyst to be prepared, that is, the palladium loading rate, can vary widely depending on various conditions and purposes such as the type of olefins, reaction conditions, and process. Generally, it is preferable to set the palladium component in a range of 0.1 to 10 parts by weight based on 100 parts by weight of the carrier.

This palladium loading rate is 0 according to the above calculation method.
．． If the amount is less than 1 part by weight, although the reaction will proceed, sufficient activity per catalyst may not be obtained;
If it exceeds 0 parts by weight, the degree of dispersion of palladium decreases, the palladium used becomes difficult to be effectively reflected in the activity, and the cost of the catalyst may increase, which is industrially disadvantageous.

The ratio of the metal component used as the co-catalyst component in this supported palladium-based catalyst to palladium varies depending on other conditions such as the type and composition of the metal component to be supported and the composition of other components. Although it cannot be determined uniformly, it is usually preferably within the range of 0.01 to 20 gram atoms, particularly preferably within the range of 0.1 to 10 gram atoms, per 1 gram atom of palladium.

In addition, the amount of the activity-promoting component to be supported as desired cannot be uniformly defined because it varies depending on the type and composition of the activity-promoting component to be added and other conditions such as the composition of other components. For example, when using an alkali metal carboxylate and a halide as the activity-promoting component, the alkali metal carboxylate and halide are each added in an amount of 0.01 to 4 gram per gram of the carrier.
It is preferable to carry it in a proportion in the range of 0 mmol.

As described above, for the synthesis of unsaturated esters by oxidative acyloxylation reaction of olefins, especially for the synthesis of unsaturated esters such as diacetoxybutene by oxidative acyloxylation reaction of conjugated dienes such as tutadiene, A high-performance supported palladium-based catalyst with significantly improved catalyst life and improved catalytic activity can be easily obtained.

As mentioned above, the supported palladium-based catalyst prepared by the catalyst preparation method of the present invention is produced by the reaction of an olefin (particularly a conjugated diene such as butadiene), a carboxylic acid, and molecular oxygen (02). For synthesis reactions (carboxylic acid esters of alcohols), ie, oxidative acyloxylation reactions, they are more advantageous than conventional supported palladium-based catalysts in terms of catalyst life and catalytic activity.

Examples of olefins to be subjected to the reaction include monoolefins such as ethylene, propylene, 1-laten, 2-laten, isolaten, pentene, hexene, heptene, and octene, 1,2-butadiene, 1,4-pentadiene, 1, Examples include non-conjugated dienes such as 4-hexadiene and 1,5-hexadiene, and conjugated dienes such as 1,3-butadiene, 1,3-pentadiene (piperylene), isoprene, and 1,3-hexadiene. . Among these, conjugated dienes such as 1,3-tutadiene and piperylene are preferred, and 1,3-butadiene is particularly preferred.

In addition, when applying the supported palladium-based catalyst prepared by the method of the present invention to the oxidative acyloxylation reaction of olefins, the catalyst life can be extended by carrying out this reaction by a gas phase reaction method, especially a gas phase flow reaction method. improvement and catalytic activity can be more effectively achieved. therefore,
Mainly from this point of view, as the olefins, those that become gaseous under the reaction conditions are preferably used.

Further, as the carboxylic acid to be reacted with the olefins, any carboxylic acid commonly used in this field can be used. Specifically, for example, aliphatic carboxylic acids such as acetic acid, propionic acid, acetic acid, isoacetic acid, pentanoic acid, hexanoic acid, alicyclic carboxylic acids such as cyclohexanecarboxylic acid, aromatic carboxylic acids such as benzoic acid, etc. can be mentioned. Among these, acetic acid is particularly preferably used. Incidentally, these may be used alone or in combination of two or more.

The molecular oxygen used in the reaction may be supplied to the reaction system as pure oxygen or as a mixed gas such as air.

The concentration of each of the olefins, carboxylic acid, and molecular oxygen in the mixed raw material (usually mixed gas) to be subjected to the reaction is not limited and can be varied within the range of 1 to 98 mol%, but is preferably The concentration of olefins is in the range of 1 to 85 mol%, the carboxylic acid is in the range of 5 to 85 mol%, and the molecular oxygen is added in an appropriate amount, usually in the range of 1 to 50 mol%, as long as the reaction gas does not become explosive. It is best to select the concentration.

Incidentally, the above reaction can also be carried out in the presence of other components such as an inert gas that do not interfere with the reaction.

The amount of the supported palladium-based catalyst to be used in carrying out the reaction should be appropriately selected depending on other conditions such as the catalyst composition, the composition and reaction conditions of the reactants, the reaction method, and the target yield of the product. However, when applying the gas phase flow reaction method, the feed rate of the raw material per 141 catalyst weight is usually 10 to 10.
100.0001/hr, preferably 100-10
,000 intersections/hr is appropriate.

The reaction temperature is not particularly limited, but is usually 1
It is appropriate to set the temperature in the range of 00 to 40°C, preferably 100 to 250°C.

The reaction pressure is also not particularly limited, and the reaction is
Although it may be carried out under reduced pressure, normal pressure or increased pressure, it is generally carried out under normal pressure or increased pressure.

The reaction is carried out in the gas phase of the reaction mixture or in a gas-liquid mixed state, and it is usually preferable to carry out the reaction in the gas phase. However, it is usually preferable to use a flow method, particularly a gas phase flow method. As a reaction method at that time,
There are no particular limitations, and any method such as a fixed bed method or a fluidized bed method can be adopted.

As described above, by carrying out the oxidative acyl oxidation reaction using the supported palladium-based catalyst prepared by the preparation method of the present invention, monoolefins such as ethylene can be converted into unsaturated monomers such as vinyl acetate. Esters can be obtained efficiently in high yields from conjugated dienes such as butadiene, for example unsaturated diesters such as diacetoxybutene, and more generally from olefins to the corresponding unsaturated esters. In particular, from butadiene, 1,4-diacetoxybutene, which is useful as a raw material for industrially particularly useful 1,4-butanediol, can be obtained in an extremely high yield.

The supported palladium-based catalyst prepared by the method of the present invention has excellent performance such as high activity for these reactions and a sufficiently long catalyst life.

[Examples] Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples unless it deviates from the scope of the present invention.

In addition, the quantitative determination of the product in the following examples was carried out by gas chromatography.

(Example 1) The concentrations of hydrochloric acid (hydrogen chloride) and tartaric acid were each 2.5.
Aqueous solution 3 prepared to be 25% by weight and 25% by weight
13.4 g of anhydrous palladium chloride, 21.9 g of antimony dioxide, and ammonium metavanadate B, B g are dissolved in 40 mJl, and a particle size of 10 to 2 is added to the solution.
00#i,m (average particle size 53JLm) silica gel l
sog (equivalent to a volume of 400 mJL) was added, and the water was slowly evaporated to dryness on a hot water bath. The obtained solid was calcined in a stream of air at 400°C for 20 hours, and then reduced in a stream of hydrogen at 200°C for 2 hours and then at 400°C for 2 hours.

Next, this was impregnated with an aqueous solution obtained by dissolving 24 g of cesium chloride and 24 g of cesium acetate in 284 mJL of water, and the water was slowly evaporated to dryness to prepare the desired supported palladium-based catalyst. .

333 mJl of this catalyst was put into a stainless steel fluidized bed reactor with an inner diameter of 55 mm, and a mixed gas containing butadiene:acetic acid:oxygen:nitrogen in a ratio of 20:20:12:48 (volume ratio) was introduced at a feed rate of 333 g/hr. , the reaction was carried out while heating to 185°C.

The results are shown in Table 1.

(Example 2) The composition of the mixed gas was 1 part tutadiene:acetic acid:oxygen:nitrogen.
A catalyst was prepared and the reaction was carried out in the same manner as in Example 1 except that the volume ratio was 0:30:3:57.

The results are shown in Table 1.

(Comparative Example 1) A catalyst was prepared in the same manner as in Example 1, except that instead of the aqueous solution of hydrochloric acid (hydrogen chloride) and tartaric acid, an aqueous solution of tartaric acid of the same concentration and not containing hydrochloric acid (hydrogen chloride) was used.

Using this catalyst, a reaction was carried out in the same manner as in Example 2 above.

The results are shown in Table 1.

(Comparative Example 2) A catalyst was prepared in the same manner as in Example 1, except that instead of the aqueous solution of hydrochloric acid (hydrogen chloride) and tartaric acid, an aqueous solution of hydrogen chloride 3 (hydrochloric acid) of the same concentration and not containing tartaric acid was used. .

A reaction was carried out in the same manner as in Example 2 using this catalyst.

The results are shown in Table 1.

(Comparative Example 3) A catalyst was prepared in the same manner as in Example 1 except that the concentration of hydrochloric acid (hydrogen chloride) in the aqueous solution of hydrochloric acid (hydrogen chloride) and tartaric acid was 20% by weight.

A reaction was carried out in the same manner as in Example 2 using this catalyst.

The results are shown in Table 1.

(Comparative Example 4) A catalyst was prepared in the same manner as in Example 1, except that instead of the aqueous solution of hydrochloric acid (hydrogen chloride) and tartaric acid, an aqueous solution of hydrogen chloride (hydrochloric acid) with a concentration of 10% by weight was used without containing tartaric acid. was prepared.

A reaction was carried out in the same manner as in Example 2 using this catalyst.

The results are shown in Table 1.

4 (Example 3) A catalyst was prepared in the same manner as in Example 1 except that 360 g of titania was used as a catalyst carrier.

A reaction was carried out in the same manner as in Example 2 using this catalyst.

The results are shown in Table 1.

Table 1 [Effects of the Invention] According to the present invention, since a specific supporting method is used in which the metal component to be supported and the carrier component are treated with an aqueous tartaric acid solution containing hydrogen halide at a specific concentration, olefins are oxidized. Production of unsaturated esters by acyloxylation reaction,
In particular, for the production of unsaturated esters such as diacetoxybutene through the oxidative acyloxylation reaction of conjugated dienes such as tutadiene, conventional methods such as supporting methods in which each is treated individually with an aqueous hydrogen halide solution or an aqueous tartaric acid solution are used. Compared to the supported palladium-based catalyst prepared by the preparation method, the catalyst life is sufficiently improved and the catalyst activity is also excellent, making it possible to provide a method for preparing a high-performance supported palladium-based catalyst. .

Claims (2)

[Claims] (1) In a method for preparing a palladium-based catalyst used for producing unsaturated diesters from olefins, carboxylic acids, and molecular oxygen, halogenation of 0.1 to 10% by weight of the supported metal component and carrier component 1. A method for preparing a catalyst for producing an unsaturated ester, which comprises treating with an aqueous tartaric acid solution containing hydrogen and then performing a reduction treatment. (2) The method for preparing a catalyst for producing unsaturated esters according to claim 1, wherein the olefin is a conjugated diene.