WO2011125541A1

WO2011125541A1 - Immobilized palladium catalyst and method for producing ketone using the same

Info

Publication number: WO2011125541A1
Application number: PCT/JP2011/057326
Authority: WO
Inventors: 清臣金田; 央司曾禰
Original assignee: Ｊｘ日鉱日石エネルギー株式会社; 国立大学法人大阪大学
Priority date: 2010-03-31
Filing date: 2011-03-25
Publication date: 2011-10-13
Also published as: JPWO2011125541A1

Abstract

Provided is an immobilized palladium catalyst comprising a polymer having amide bonds in the side chains and a palladium compound immobilized on this polymer. Also provided is a method for producing a ketone by oxidizing an olefin having one or more carbon-carbon double bonds per molecule, in the presence of water and molecular oxygen and under conditions of an oxygen pressure of 0.3 MPa or greater, using the immobilized palladium catalyst in order to cause oxo groups to bond with at least one of the carbon atoms that form the carbon-carbon double bond.　

Description

Immobilized palladium catalyst and method for producing ketone using the same

The present invention relates to a palladium catalyst immobilized on a polymer and a method for producing a ketone by oxidizing an olefin using the palladium catalyst.

Carbonyl compounds such as ketones such as methyl ethyl ketone (MEK), methyl isobutyl ketone (MIBK) and acetone, and aldehydes typified by acetaldehyde are useful as solvents and chemical raw materials, and are used in various fields. Such a carbonyl compound is usually produced by a two-stage reaction method in which an alcohol produced by hydration of an olefin is dehydrogenated. As a simpler method, a one-stage reaction method in which an olefin is directly oxidized is also known. ing.

For example, Tetrahedron Letters, 1985, Vol. 26, No. 19, pages 2263-2264 (Non-Patent Document 1) discloses a method of oxidizing terminal and internal olefins using a palladium catalyst, a copper catalyst, polyethylene glycol and water. Is disclosed. J. et al. Org. Chem. 1990, 55, 2924-2927 (Non-Patent Document 2) discloses an improved Wacker method in which a cyclic or internal olefin is reacted with p-benzoquinone using a strong acid in the presence of a palladium catalyst. Yes. Japanese Patent Laid-Open No. 5-140020 (Patent Document 1) discloses palladium, oxyacid salts of metals having redox activity (copper, iron, etc.), hydroquinones, and compounds capable of converting the hydroquinones into quinones (iron In the presence of phthalocyanine, cobalt tetraphenylporphyrin and the like, a method for producing a carbonyl compound is disclosed in which an olefin is oxidized with molecular oxygen in an acidic aqueous solution. Japanese Patent Application Laid-Open No. 7-17891 (Patent Document 2) discloses a method for producing a carbonyl compound in which an olefin and water are reacted in the presence of a palladium compound, a copper compound and an organic phosphorus compound. In Japanese Patent Application Laid-Open No. 7-149585 (Patent Document 3), in the presence of a palladium compound, a polyoxoanionic compound and an iron-containing compound, an olefin and oxygen gas are contained in a solvent comprising an oxygen-containing compound or a sulfur-containing compound. A method for producing a carbonyl compound to be reacted is disclosed. Japanese Patent Laid-Open No. 8-67648 (Patent Document 4) discloses a method for producing a ketone in which an olefinic compound is oxidized using p-benzoquinone in the presence of water and a palladium compound. For example, a method for producing a ketone using a sulfonic acid ion exchanger or the like is disclosed. However, in these methods, since various compounds such as copper and benzoquinone are added in addition to the palladium catalyst, the reaction system is complicated, and it is not easy to separate and recover the palladium catalyst from the reaction solution after the oxidation reaction. Therefore, it was not suitable as an industrial method for producing ketones.

Japanese Patent Application Laid-Open No. 5-148177 (Patent Document 5) includes water and urea in the presence of a palladium compound supported on a carrier such as activated carbon and a copper compound and / or an iron compound. A method for producing a carbonyl compound that oxidizes an olefin in solution is disclosed. Japanese Patent Laid-Open No. 2002-191979 (Patent Document 6) discloses the production of a ketone that oxidizes alkenes with molecular oxygen in the presence of an oxidation catalyst composed of a palladium compound supported on activated carbon, a heteropolyacid, and a strong acid. A method is disclosed. Japanese Patent Application Laid-Open No. 2008-231043 (Patent Document 7) discloses a method for producing a ketone in which an olefin is reacted with molecular oxygen in the presence of a palladium source, water and a protonic acid supported on a mesoporous silicate. In these methods, although the palladium catalyst can be easily separated and recovered from the reaction solution after the oxidation reaction, in addition to the palladium catalyst, various compounds such as copper and acid are added, so the reaction system is complicated and industrial It is not suitable as a typical method for producing ketones.

Meanwhile, Angew. Chemie. Int. Ed. 2006, Vol. 45, pp. 481-485 (Non-patent Document 3), a reoxidant is used when oxidizing a terminal olefin in a polar solvent such as N, N-dimethylacetamide in the presence of a palladium catalyst. Discloses a method for producing ketones using molecular oxygen. In this method, since the compound to be added in addition to the palladium catalyst is molecular oxygen, the reaction system is simple and the yield of ketone is very high. However, in this method, it is not easy to separate and recover the palladium catalyst from the reaction solution after the oxidation reaction, and it is not suitable as an industrial ketone production method from the viewpoint of reusing the palladium catalyst.

JP-A-5-140020 JP-A-7-17891 Japanese Patent Application Laid-Open No. 7-149685 JP-A-8-67648 JP-A-5-148177 Japanese Patent Laid-Open No. 2002-191979 JP 2008-231043 A

The present invention has been made in view of the above-described problems of the prior art, and provides an immobilized palladium catalyst that can be easily recovered and reused when an olefin is oxidized to produce a corresponding ketone. The purpose is to do. Furthermore, an object of the present invention is to provide a method capable of easily producing a ketone from an olefin with a high yield and a high selectivity.

As a result of intensive studies to achieve the above object, the present inventors have been able to reliably immobilize a palladium compound having catalytic ability by using a polymer having an amide bond in the side chain as a carrier, By using such an immobilized palladium catalyst, it becomes possible to easily recover and reuse the immobilized palladium catalyst from the solution after the reaction, and further oxidize the olefin with high yield and high selectivity. Thus, the inventors have found that ketones can be easily produced, and have completed the present invention.

That is, the immobilized palladium catalyst of the present invention comprises a polymer having an amide bond in the side chain and a palladium compound immobilized on the polymer. In such an immobilized palladium catalyst, the side chain preferably forms a cyclic structure, and the polymer having an amide bond in the side chain is more preferably polyvinylpyrrolidone.

In addition, the method for producing a ketone of the present invention uses the immobilized palladium catalyst, and in the presence of water and molecular oxygen, the oxygen pressure is 0.3 MPa or more, and one or more carbon-carbon atoms in the molecule. An olefin having a double bond is oxidized, and an oxo group is bonded to at least one carbon atom constituting the carbon-carbon double bond. In such a method for producing a ketone, it is preferable to oxidize an olefin in the absence of a copper catalyst.

According to the present invention, it is possible to obtain an immobilized palladium catalyst that can be easily recovered and reused when an olefin is oxidized to produce a corresponding ketone. Further, by using such an immobilized palladium catalyst, it is possible to produce a ketone from an olefin with a high yield and high selectivity by a simple method of supplying molecular oxygen.

Hereinafter, the present invention will be described in detail on the basis of preferred embodiments thereof.

First, the immobilized palladium catalyst of the present invention will be described. The immobilized palladium catalyst of the present invention comprises a polymer having an amide bond in the side chain and a palladium compound immobilized on the polymer.

<Amide bond-containing polymer>
The polymer used for the immobilized palladium catalyst of the present invention is not particularly limited as long as it is a polymer having an amide bond in the side chain (hereinafter referred to as “amide bond-containing polymer”), but an inert species Pd black is used. From the viewpoint that the palladium compound can be reliably fixed without being generated, a polymer in which the side chain having an amide bond forms a cyclic structure is preferable. Specifically, the following formulas (1) to (2):

(In the formulas (1) to (2), R ¹ and R ² each independently represents an alkyl group having 1 to 4 carbon atoms or a phenyl group, and when R ¹ and R ² are both alkyl groups, they are bonded to each other. And may form a ring structure.)
And polymers having at least one of the structures represented by the following formulas (3) to (4):

(Equation (3) - (4), ^{R 1} and ^{R 2} have the same meanings as ^{R 1} and ^{R 2} in the formula (1) to (2).)
From the viewpoint that the vinyl compound containing at least one of the structural units represented by (more preferably repeating units) is preferable, and the palladium compound can be reliably fixed without generating Pd black which is an inactive species. Following formula (5):

(In the formula (5), A represents a cyclic structure having 2 to 8 carbon atoms.)
A vinyl polymer containing a structural unit represented by (more preferably a repeating unit) is more preferred.

Examples of the vinyl polymer containing the repeating unit represented by the formula (5) include polyvinylpyrrolidone (poly (N-vinylpyrrolidone)), polyvinylcaprolactam (poly (N-vinyl-ε-caprolactam)), N-vinyl. Examples thereof include a copolymer of pyrrolidone and vinyl acetate, and among them, polyvinyl pyrrolidone is preferable.

The method for producing such an amide bond-containing polymer is not particularly limited. For example, in the case of a vinyl polymer, a vinyl polymer having an amide bond such as N-vinyl-2-pyrrolidone or N-vinyl-2-caprolactam. Examples thereof include a method of (co) polymerizing monomers; a method of graft polymerization of a vinyl monomer having an amide bond to unmodified polyvinyl.

The viscosity average molecular weight of the amide bond-containing polymer used in the present invention is not particularly limited, but is preferably 40000 or more from the viewpoint of easy separation and recovery of the immobilized palladium catalyst. The upper limit of the viscosity average molecular weight of the amide bond-containing polymer is not particularly limited, but is preferably 400,000 or less from the viewpoint of causing the immobilized palladium catalyst of the present invention to act as a homogeneous catalyst during the reaction.

<Palladium compound>
The palladium compound used in the immobilized palladium catalyst of the present invention is not particularly limited as long as it has a palladium atom and has catalytic ability, and those used in the production of ketones can be used. Examples of such palladium compounds include palladium inorganic salts such as palladium sulfate, palladium nitrate and palladium carbonate; polyoxoanionic compounds containing palladium such as heteropolyacid palladium salts and isopolyacid palladium salts; halogens such as palladium chloride and palladium bromide. Palladium halides; Palladium acid salts such as sodium tetrachloropalladate, sodium tetrabromopalladate, potassium tetrachloropalladate and potassium tetrabromopalladate; ammine complexes of palladium halides such as tetraamminepalladium dichloride and diamminepalladium tetrachloride; palladium hydroxide And palladium compounds and complexes such as palladium oxide; palladium acetate Palladium organic acid salts such as palladium (II) trifluoroacetate; palladium-containing organic compounds such as palladium acetylacetonate and alkylpalladium compounds; nitrile complexes of palladium halides such as diacetonitrile palladium dichloride and dibenzonitrile palladium dichloride; tetrakis (triphenylphosphine) Palladium phosphine complexes represented by palladium; palladium amine complexes represented by palladium on ethylenediaminetetraacetate; organic palladium compounds and complexes such as chloroform adduct of tris (dibenzylideneacetone) dipalladium and cyclooctadienepalladium dichloride; palladium colloid and Examples thereof include active metal palladium such as highly dispersed palladium metal. These palladium compounds may be used alone or in combination of two or more.

Of these palladium compounds, palladium halides and nitrile complexes of palladium halides are preferable, and palladium halides are more preferable, from the viewpoint of increasing yield and selectivity in the olefin oxidation reaction described below.

The amount of the palladium compound immobilized in the immobilized palladium catalyst of the present invention is preferably 1 to 100 mg per 1 g of the amide group-containing polymer, more preferably 2 to 20 mg. When the amount of the palladium compound immobilized is less than the lower limit, the olefin oxidation reaction does not proceed sufficiently, and it is not possible to produce a ketone in a high yield. Pd black is generated and the olefin oxidation reaction does not proceed sufficiently.

<Method for producing immobilized palladium catalyst>
The immobilized palladium catalyst of the present invention can be prepared by mixing the amide bond-containing polymer and a palladium compound. At this time, it is preferable to use a solvent. Examples of such a solvent include water, dimethylacetamide (DMA), dimethylformamide (DMF), dimethylsulfoxide (DMSO), etc. Among them, the palladium compound can be uniformly dispersed, and the palladium compound is uniformly dispersed. From the viewpoint of obtaining a catalyst immobilized in the above state, water is preferable.

Next, a method for producing the ketone of the present invention will be described. The method for producing a ketone of the present invention comprises the use of the immobilized palladium catalyst of the present invention in the presence of water and molecular oxygen in the presence of one or more carbon- In this method, an olefin having a carbon double bond is oxidized and an oxo group is bonded to at least one carbon atom constituting the carbon-carbon double bond.

<Olefin>
The olefin used in the method for producing a ketone of the present invention is not particularly limited, and examples thereof include known olefins having one or more carbon-carbon double bonds (hereinafter abbreviated as “C═C bond”) in the molecule. Examples thereof include a terminal olefin in which the C═C bond is present at the molecular end, and an internal olefin and a cyclic olefin in which the C═C bond is present at a site other than the terminal in the molecule. Specifically, the following formula (6):

(In the formula (6), R ³ to R ⁶ each independently represents one selected from the group consisting of a hydrogen atom, an alkyl group, an alkenyl group, and an aryl group, and “R ³ and R ⁵ ” and / or “ When R ⁴ and R ⁶ ″ are an alkyl group or an alkenyl group, they may be bonded to each other to form a ring structure.)
The olefin represented by these is mentioned.

Among the olefins, when R ³ and R ⁴ in the formula (6) are both hydrogen atoms, or when both R ⁵ and R ⁶ are hydrogen atoms, such olefins are terminal olefins. In the formula (6), at least one of R ³ and R ⁴ is any one of an alkyl group, an alkenyl group, and an aryl group, and at least one of R ⁵ and R ⁶ is an alkyl group, Such olefins are internal olefins when they are either alkenyl groups or aryl groups. Further, when R ³ and R ⁵ are an alkyl group or an alkenyl group and are bonded to each other to form a ring structure, or R ⁴ and R ⁶ are an alkyl group or an alkenyl group and are bonded to each other to form a ring structure Such olefins are cyclic olefins.

The alkyl group and the alkenyl group may be linear, branched or cyclic. The carbon number of the alkyl group is preferably 1 to 12, and more preferably 4 to 12. Furthermore, a hetero atom may be contained as long as the effects of the present invention are not impaired. The position of the C═C bond in the alkenyl group is not particularly limited, and may be at the terminal or inside of the alkenyl group. Examples of the aryl group include a phenyl group, a methylphenyl group, and a benzyl group, and the aryl group may contain a hetero atom as long as the effects of the present invention are not impaired.

Formula (6) in the R ³ and R ^_5, or, if R ⁴ and R ⁶ form a ring structure having bonded to C = C bond to each other, a portion other than the ring structure (e.g., When R ³ and R ⁵ are combined to form a ring structure, R ⁴ and / or R ⁶ ) may also have a C═C bond.

Specific examples of the terminal olefin include ethylene, propylene, 1-butene, 2-methyl-1-propylene, 2-pentene, 2-methyl-1-butene, 1-hexene, 2-methyl-1-pentene, 3 -Methyl-1-pentene, 1-heptene, 4-methyl-1-hexene, 1-octene, 5-methyl-1-heptene, 1-nonene, 6-methyl-1-octene, 2-phenyl-1-propylene 2-cyclohexyl-1-propylene, 1-decene, 7-methyl-1-nonene, 2-phenyl-1-butene, 2-cyclohexyl-1-butene, 1-undecene, 1-dodecene, 1-tetradecene, Monoolefins such as hexadecene; 1,4-pentadiene, 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, 1,9 Such as dienes, and the like, such as decadiene.

Specific examples of the internal olefin include 2-butene, 2-pentene, 2-methyl-2-butene, 2-hexene, 3-hexene, 4-methyl-2-pentene, 2-heptene and 3-heptene. 5-methyl-2-hexene, 2-octene, 3-octene, 4-octene, 6-methyl-2-heptene, 2-nonene, 7-methyl-2-octene, 1-phenyl-1-propylene, -Cyclohexyl-1-propylene, 2-decene, 3-decene, 4-decene, 5-decene, 8-methyl-2-nonene, 1-phenyl-2-butene, 1-cyclohexyl-2-butene, 5-undecene , 6-dodecene, 7-tetradecene, 8-hexadecene monoolefins; 1,3-pentadiene, 2,4-hexadiene, 2,5-heptadiene, 1,3 Octadiene, such as dienes, and the like, such as 2,4-decadiene. Further, these internal olefins can be used without distinction from isomers such as cis type and trans type.

Further, specific examples of the cyclic olefin include cycloalkenes such as cyclopentene, cyclohexene, cyclooctene, and cyclodecene, cycloalkadienes represented by cyclooctadiene, and alkyl groups in these cycloalkenes and cycloalkadienes. And those substituted with an alkenyl group (for example, vinylcyclohexene and allylcyclohexene).

These olefins may be used alone or in combination of two or more.

In the method for producing a ketone of the present invention, the olefin concentration is preferably 0.01 to 5 mol / L, more preferably 0.05 to 1 mol / L. If the olefin concentration is less than the lower limit, the ketone cannot be obtained in high yield. On the other hand, if the olefin concentration exceeds the upper limit, the olefin oxidation reaction does not proceed sufficiently, and the ketone is produced in high yield. It tends to be impossible.

<Water>
In the method for producing a ketone of the present invention, a ketone is produced by reacting an olefin with water. The amount of water added is not particularly limited as long as it is a required amount for the reaction, and can be appropriately set depending on the olefin to be used, the immobilized palladium catalyst, the solvent, the reaction system and the conditions. The specific amount of water added is preferably 0.5 to 70 parts by volume, more preferably 1 to 50 parts by volume with respect to 100 parts by volume of the solvent when the reaction is carried out in a solvent. When the amount of water added is less than the lower limit, a sufficient oxidation reaction rate cannot be obtained, and the yield of ketone tends to decrease. On the other hand, when the upper limit is exceeded, the palladium component tends to remain as Pd black, and the catalytic activity tends to be reduced. In addition, since the solubility of olefin in water is low, the contact efficiency between the olefin and the immobilized palladium catalyst is lowered, a sufficient oxidation reaction rate cannot be obtained, and the yield of ketone tends to be lowered.

<Oxygen>
In the method for producing a ketone of the present invention, the immobilized palladium catalyst after oxidizing the olefin is reoxidized using molecular oxygen. At this time, since a cocatalyst such as a copper catalyst is not substantially used, the oxidation reaction of the olefin is not inhibited by the copper catalyst, and the corresponding ketone can be produced from various olefins with high yield and high selectivity. Become.

Examples of the molecular oxygen supply source include oxygen gas, oxygen-enriched air, air, a mixed gas of oxygen gas and dilution gas (collectively referred to as “oxygen-containing gas”), and the like. Examples of the dilution gas include nitrogen gas, helium gas, argon gas, and carbon dioxide, and nitrogen gas is usually used. In the method for producing a ketone of the present invention, a gas other than these oxygen-containing gas and dilution gas can be used in combination as long as the effects of the invention are not impaired. In addition, such an oxygen-containing gas may be supplied by mixing with water or a solvent as necessary.

In the method for producing a ketone of the present invention, an oxygen-containing gas is supplied at an oxygen pressure of 0.3 MPa or more. When the oxygen pressure is less than the lower limit, Pd black which is an inert species is generated, and ketone cannot be produced in a high yield. Moreover, in order to produce a ketone more stably, the oxygen pressure is preferably 0.4 MPa or more. On the other hand, the upper limit of the oxygen pressure is preferably 1 MPa or less. When the oxygen pressure exceeds the above upper limit, oxygenated by-products tend to be formed in some olefins (for example, in the case of cyclohexene, 2-cyclohexen-1-one in which the allylic position is oxidized is generated).

<Solvent>
In the method for producing a ketone of the present invention, an olefin is usually oxidized using a solvent. By using the solvent, the olefin can be efficiently oxidized, and the corresponding ketone can be produced with high yield and high selectivity.

Such a solvent is not particularly limited, and for example, a solvent used in the production of a ketone by oxidation of a known olefin such as acetonitrile, tetrahydrofuran, N, N-dimethylformamide, 1,4-dioxane can be used. The amount of the solvent used is appropriately set so that the concentrations of the olefin and the immobilized palladium catalyst are within a predetermined range.

<Oxidation reaction>
In the method for producing a ketone of the present invention, the immobilized palladium catalyst of the present invention is used, and in the presence of water and molecular oxygen, at least one carbon- A ketone is produced by oxidizing an olefin having a carbon double bond and attaching an oxo group (═O) to at least one carbon atom constituting the C═C bond in the olefin. In the present specification, such a ketone is referred to as “corresponding ketone”.

In the method for producing a ketone of the present invention, the oxidation reaction method is not particularly limited, but usually the reaction is carried out using a solvent and heating and stirring. Moreover, a batch type, a semi-batch type, a semi-continuous type, a continuous flow type, or a combination thereof can be adopted. Moreover, there is no restriction | limiting in particular also in the supply method of each components, such as an olefin, You may supply in a liquid state or a gaseous state.

As a specific production method, a catalyst solution prepared by mixing the immobilized palladium catalyst and a solvent or a mixed solution in which an olefin is mixed with the catalyst solution is charged into a batch reactor and reacted. Batch type; semi-batch type or semi-continuous type in which the olefin and the oxygen-containing gas are continuously supplied into the catalyst solution, or the oxygen-containing gas is continuously supplied into the mixed solution; Examples thereof include a continuous flow type in which an olefin and the oxygen-containing gas are simultaneously passed through a reaction region.

In the ketone production method of the present invention, the concentration of the immobilized palladium catalyst is preferably 0.002 to 1 mol / L, more preferably 0.001 to 0.05 mol / L, in terms of palladium compound concentration. If the concentration of the immobilized palladium catalyst is less than the lower limit, the oxidation reaction of the olefin does not proceed sufficiently, and the ketone cannot be produced in a high yield. On the other hand, if the concentration exceeds the upper limit, it is an inert species. Pd black is generated and the olefin oxidation reaction does not proceed sufficiently.

In the method for producing a ketone of the present invention, when the olefin and the oxygen-containing gas are continuously supplied into the catalyst solution, the olefin supply rate is preferably 10 to 5000 mol / h per 1 mol of palladium. When the olefin supply rate is less than the lower limit, the production amount of ketone per unit time tends to decrease. On the other hand, when the upper limit is exceeded, Pd Black, which is an inert species, is produced, and the ketone is obtained in high yield. It tends to be impossible. The supply rate of the oxygen-containing gas is appropriately adjusted so that the oxygen pressure in the reaction system is within the above range.

In the method for producing a ketone of the present invention, the reaction temperature for carrying out the oxidation reaction is preferably 30 to 200 ° C., more preferably 40 to 100 ° C. When the reaction temperature is within the above range, the immobilized palladium catalyst of the present invention dissolves in a stable state in which a polymer having an amide bond in the side chain and a palladium compound are complexed, so that the reaction system becomes uniform and high Ketones can be produced from olefins in high yield and high selectivity. On the other hand, if it is less than the lower limit, the immobilized palladium catalyst tends to precipitate and the reaction system becomes heterogeneous, so the reaction rate tends to be slow and the yield of ketone tends to decrease. Side reactions such as the isomerization of benzene occur and the selectivity of the corresponding ketone tends to decrease.

In the method for producing a ketone of the present invention, the concentration of the copper catalyst used in the conventional Wacker method is preferably 0.03 mol / L or less, more preferably 0.01 mol / L or less, Particularly preferred is 0.003 mol / L or less. When the concentration of the copper catalyst exceeds the upper limit, the yield of the corresponding ketone tends to decrease. From such a viewpoint, in the method for producing a ketone of the present invention, it is most preferable to oxidize an olefin in the absence of a copper catalyst (concentration: 0 mol / L). The copper catalyst promotes reoxidation of the palladium catalyst in the conventional Wacker method, but in the olefin Wacker reaction according to the present invention, the yield of the corresponding ketone decreases due to the coexistence of the copper catalyst. From this tendency, it is presumed that the activity of the immobilized palladium catalyst that proceeds efficiently by molecular oxygen is inhibited.

The ketone thus obtained can be obtained as a single compound or a mixture having a desired purity or composition by separation and purification according to a conventional method. In the method for producing a ketone of the present invention, since there are few side reactions during the oxidation reaction, the unreacted raw material can be recovered and used again for the production of the ketone. Also, the solvent can be recovered and reused.

In the method for producing a ketone of the present invention, the immobilized palladium catalyst can be easily separated and recovered by filtration or centrifugation by cooling the reaction solution after completion of the oxidation reaction to near room temperature. That is, the immobilized palladium catalyst is uniformly dispersed in the solvent under the reaction temperature conditions, but precipitates when cooled to near room temperature. Therefore, the precipitate can be easily recovered by collecting the precipitate by filtration or centrifugation. It can be used. Furthermore, in the method for producing a ketone of the present invention, since the immobilized palladium catalyst is hardly deteriorated, it can be reused in the production of the next ketone as it is after the separation and recovery without performing a regeneration treatment. A decrease in yield and the like is also unlikely to occur.

Hereinafter, the present invention will be described more specifically based on examples and comparative examples, but the present invention is not limited to the following examples.

Example 1
In an autoclave reactor, palladium (II) chloride (1.8 mg, 0.01 mmol), polyvinylpyrrolidone (PVP, 0.5 g, “Polyvinylpyrrolidone K30” manufactured by Tokyo Chemical Industry Co., Ltd.), viscosity average molecular weight (Mt): 4 And water (2.0 ml) were added and stirred. As a result, palladium chloride was immobilized on polyvinylpyrrolidone to produce a pale yellow precipitate (hereinafter referred to as “Pd-PVP catalyst”).

Next, acetonitrile (5 ml) and 1-decene (112 mg, 0.5 mmol) were added to the reactor after the Pd—PVP catalyst was formed to depressurize the reactor, and oxygen gas was then supplied to the reactor. The inside was pressurized to 0.6 MPa and an oxidation reaction was carried out at 80 ° C. for 5 hours. At this time, the inside of the reaction system was uniform.

After completion of the reaction, the mixture was cooled to room temperature, and separated into a layer containing the product and a layer containing the Pd-PVP catalyst. The product was analyzed using a gas chromatograph (“GC-2014” manufactured by Shimadzu Corporation, column: KOCL 3 m) equipped with an FID detector. The results are shown in Table 1.

(Example 2)
The oxidation reaction was carried out in the same manner as in Example 1 except that the pressure inside the reactor was increased to 0.3 MPa. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 1.

(Example 3)
The oxidation reaction was carried out in the same manner as in Example 1 except that cyclohexene (246 mg, 3.0 mmol) was used instead of 1-decene and the reaction time was changed to 4 hours. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 1.

Example 4
2-butene (375 mg, 6.70 mmol) was used instead of 1-decene, the amount of palladium (II) chloride was 6.1 mg (0.034 mmol), the amount of PVP was 1.5 g, and the amount of water was 6. The oxidation reaction was carried out in the same manner as in Example 1 except that 0 ml, the amount of acetonitrile was changed to 15 ml, and the reaction time was changed to 6 hours. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 1.

(Example 5)
Cyclopentene (205.6 mg, 3.02 mmol) was used instead of 1-decene, the amount of palladium (II) chloride was 6.1 mg (0.034 mmol), the amount of PVP was 1.5 g, and the amount of water was 6. The oxidation reaction was carried out in the same manner as in Example 1 except that 0 ml, the amount of acetonitrile was changed to 15 ml, and the reaction time was changed to 6 hours. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 1)
The oxidation reaction was carried out in the same manner as in Example 1 except that the pressure inside the reactor was increased to 0.1 MPa. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 1.

(Comparative Example 2)
The oxidation reaction was carried out in the same manner as in Comparative Example 1 except that the oxidation reaction time was changed to 15 hours. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 1.

As is clear from the results shown in Table 1, it was confirmed that even when palladium (II) chloride was immobilized on polyvinylpyrrolidone, it exhibited sufficient catalytic activity in the oxidation reaction of 1-decene or 2-butene. (Examples 1-2, 4). Further, when the oxygen pressure is 0.3 MPa or more (Examples 1 to 2 and 4), 2-decanone or methyl ethyl ketone is produced in a higher yield than when the oxygen pressure is 0.1 MPa (Comparative Examples 1 and 2). And formation of isomers was not observed. The reason why the yield of 2-decanone or methyl ethyl ketone is high when the oxygen pressure is 0.3 MPa or higher is not necessarily clear, but the present inventors speculate as follows. That is, in Comparative Examples 1 and 2, since the solution after the reaction was black, zero-valent Pd produced by the oxidation reaction was aggregated as it was, and reoxidation with oxygen did not proceed sufficiently. It is inferred that On the other hand, in Examples 1 to 2 and 4, since the solution after completion of the reaction was not black, it was inferred that the zero-valent Pd produced by the oxidation reaction was reoxidized. In particular, in Examples 1 and 2, Is presumed that the zero-valent Pd produced by the oxidation reaction was efficiently reoxidized because the solution after the reaction was yellow.

In addition, when hexahexene or cyclopentene was oxidized (Examples 3 and 5), cyclohexanone or cyclopentanone was produced in a high yield. From this, it was confirmed that the corresponding ketones can be produced from various olefins by using the immobilized palladium catalyst of the present invention.

(Example 6)
An oxidation reaction (first time) was performed in the same manner as in Example 1 except that the reaction time was changed to 6 hours. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 2.

Next, the cooled solution was centrifuged (3000 rpm × 10 minutes) to recover the lower layer Pd-PVP catalyst. The obtained Pd-PVP catalyst was put into an autoclave reactor, water (2.0 ml), acetonitrile (5 ml) and 1-decene (112 mg, 0.5 mmol) were added to depressurize the inside of the reactor, Oxygen gas was supplied to pressurize the inside of the reactor to 0.6 MPa, and an oxidation reaction (second time) was performed at 80 ° C. for 6 hours. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 2.

Further, after recovering the Pd-PVP catalyst in the same manner as described above, a third oxidation reaction was performed under the same conditions as described above. The product after completion of the reaction was analyzed in the same manner as in Example 1. The results are shown in Table 2.

As is apparent from the results shown in Table 2, by using the immobilized palladium catalyst of the present invention, it becomes possible to separate and recover the catalyst, which was difficult with the conventional palladium catalyst, and the reused Pd-PVP catalyst. Even in this case, no isomer was observed and 2-decanone could be obtained in high yield.

As described above, according to the present invention, it is possible to obtain an immobilized palladium catalyst that can be easily recovered and reused when an olefin is oxidized to produce a corresponding ketone. Further, by using such an immobilized palladium catalyst, it is possible to produce a ketone from an olefin with a high yield and high selectivity by a simple method of supplying molecular oxygen.

Therefore, the method for producing a ketone of the present invention is high in yield and selectivity of the ketone, and is simple, and further, the used palladium catalyst can be easily recovered and reused, which is very economical. It is advantageous. That is, the ketone obtained by this method is useful as an industrial raw material such as a solvent or a chemical raw material.

Claims

An immobilized palladium catalyst comprising a polymer having an amide bond in the side chain and a palladium compound immobilized on the polymer.
The immobilized palladium catalyst according to claim 1, wherein the side chain forms a cyclic structure.
The immobilized palladium catalyst according to claim 2, wherein the polymer having an amide bond in the side chain is polyvinylpyrrolidone.
Using the immobilized palladium catalyst according to any one of claims 1 to 3, in the presence of water and molecular oxygen, the oxygen pressure is 0.3 MPa or more, and at least one in the molecule. A method for producing a ketone, wherein an olefin having a carbon-carbon double bond is oxidized to bond an oxo group to at least one carbon atom constituting the carbon-carbon double bond.
The method for producing a ketone according to claim 4, wherein the olefin is oxidized in the absence of a copper catalyst.