JP4063383B2 - Oxidation catalyst and oxidation method using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an oxidation catalyst useful for efficiently oxidizing an organic substrate, a method for oxidizing an organic substrate using the oxidation catalyst, and a method for producing a ketone compound.
[0002]
[Prior art]
From the viewpoints of synthesis and environmental protection, a method for obtaining a corresponding oxidized compound by oxidizing an organic substrate using molecular oxygen as an oxidizing agent has been attracting attention and various studies have been made.
In Angew. Chem. Int. Ed. Engl. 23 (1984) 453, and J. Chem. Soc. A (1971) 1321, cycloalkenes such as cyclohexene are formed by a palladium (II) catalyst in the presence of benzoquinone. It is described that the allylic position is acetoxylated and converted to 3-acetoxy-1-cycloalkene. In this oxidation reaction, benzoquinone is used as a stoichiometric reoxidant that converts palladium (0) reduced in the oxidation cycle to palladium (II).
J. Org. Chem. 55 (1990) 975 discloses a method for acetoxylation of cyclohexene using angan dioxide as a dehydrogenating agent for converting the resulting hydroquinone to benzoquinone in the presence of a catalytic amount of benzoquinone. It is disclosed. In J. Org. Chem. 55 (1990) 5574, molecular oxygen is used as an oxidizing agent, and in the acetoxylation reaction of olefins and dienes using palladium (II) as a catalyst, benzoquinone, copper (II) acetate and A method of using these in combination is disclosed.
Chem. Lett. (1993) 1699, and J. Org. Chem. 58 (1993) 6421 include benzylamines and benzyl alcohols in the presence of heteropoly acid salts (phosphovanad molybdates) in the form of molecular oxygen. It has been reported that when oxidised, Schiff base imine and carbonyl compounds are obtained, respectively. In addition, hydroquinones have been dehydrogenated with molecular oxygen and converted to quinones by the action of heteropolyacid salt through the study of oxidation reactions using molecular oxygen catalyzed by phosphovanad molybdate. Has been clarified [J. Org. Chem. 58 (1993) 6421].
[0003]
In Journal of Molecular Catalysis A: Chemical 114 (1996) 113, based on the series of studies described above, palladium (0) produced in the oxidation cycle is reoxidized in the oxidation reaction of alkenes catalyzed by palladium (II). As a reoxidation system for this purpose, studies using hydroquinones / heteropolyacid salts / oxygen have been made. When a catalyst system composed of a divalent palladium compound, hydroquinones and a heteropolyacid salt is used, an acetoxylation reaction of a cycloalkene, a Wacker-type reaction of an alkene (eg, cyclohexene, styrene, etc.) by molecular oxygen, It has been reported that the acetalization reaction of monosubstituted alkenes proceeds smoothly. This document also discloses an example in which a divalent palladium compound or heteropolyacid salt is supported on activated carbon. In addition, as activated carbon, specific surface area 1450m²/ G, pore size (volume): Activated carbon of 15-25 angstrom (0.58 ml / g) (manufactured by Wako Pure Chemical Industries, Ltd.) is used.
However, the above method is not always satisfactory in terms of the yield of the target oxidation product from an industrial point of view.
[0004]
[Problems to be solved by the invention]
Accordingly, an object of the present invention is to provide an oxidation catalyst and an oxidation method capable of efficiently oxidizing an organic substrate.
Another object of the present invention is to provide a process for obtaining a corresponding ketone from cycloalkene or alkene in good yield.
[0005]
[Means for Solving the Problems]
  As a result of intensive studies to achieve the above object, the inventors of the present invention, when a catalyst component is supported on a specific activated carbon in a catalyst composed of a divalent palladium compound and a heteropolyacid or a salt thereof, The inventors found that the yield was remarkably improved and completed the present invention.
  That is, the present invention is an oxidation catalyst composed of (A) a divalent palladium compound and (B) a heteropolyacid or a salt thereof, and at least one catalyst component has a sulfur (S) content of 0 to 0.0.07% By weightObtained from polymer raw materialsAn oxidation catalyst supported on activated carbon is provided. The present invention also provides an oxidation method for oxidizing an organic substrate with molecular oxygen in the presence of the above oxidation catalyst. The present invention further provides a method for producing a ketone in which an alkene or cycloalkene is oxidized with molecular oxygen in the presence of the above oxidation catalyst to produce a corresponding ketone.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
The oxidation catalyst of the present invention contains (A) a divalent palladium compound and (B) a heteropolyacid or a salt thereof as catalyst components.
[0007]
[Divalent Palladium Compound (A)]
Examples of the divalent palladium compound (A) include organic acid salts such as palladium acetate (II) and paradium cyanide (II); organic complexes such as dichlorobis (benzonitrile) palladium (II); palladium fluoride (II ), Palladium chloride (II), palladium bromide (II), palladium iodide (II) and other halides; palladium nitrate (II), oxyacid salts such as palladium sulfate (II); palladium (II) oxide; sulfide Examples thereof include inorganic complexes such as palladium (II); palladium (II) selenide; palladium hydroxide (II); tetraammine palladium (II) chloride.
[0008]
Preferred divalent palladium compounds include organic acid salts or organic complexes such as palladium (II) acetate, halides such as palladium (II) chloride, oxygen acid salts such as palladium (II) sulfate, and the like. Of these, organic acid salts such as palladium (II) acetate are preferred.
A bivalent palladium compound (A) can be used individually or in mixture of 2 or more.
[0009]
[Heteropolyacid or salt thereof (B)]
A heteropolyacid is a condensate of oxygen acids containing two or more different types of central ions, and is also called a heteronuclear condensed acid. Heteropolyacids include, for example, oxygen acid ions of elements such as P, As, Sn, Si, Ti, and Zr (for example, phosphoric acid and silicic acid) and oxygen acid ions of elements such as V, Mo, and W (for example, , Vanadic acid, molybdic acid, tungstic acid, etc.), and various heteropolyacids are possible by combinations thereof.
[0010]
The heteroatom of the oxygen acid that constitutes the heteropolyacid is not particularly limited. For example, Cu, Be, B, Al, C, Si, Ge, Sn, Ti, Zr, Ce, Th, N, P, As, Sb, Examples thereof include V, Nb, Ta, Cr, Mo, W, U, Se, Te, Mn, I, Fe, Co, Ni, Rh, Os, Ir, and Pt. A preferred heteropolyacid contains at least one element of P, Si, V, Mo and W, more preferably at least one selected from P and V, Mo and W (particularly V and Mo). Contains elements. Particularly preferred heteropolyacids contain at least P and V as constituent elements.
[0011]
Examples of the heteropolyacid anion constituting the heteropolyacid or a salt thereof include the anions represented by the following composition formulas.
XM₁₂O₄₀, XM_TenO₃₄, XM₁₂O₄₂, XM₁₁O₃₉, XM_TenO_m, XM₉O₃₂, XM₆O_{twenty four}, X₂M₁₈O₆₂, X₂M₁₈O₅₆, X₂M₁₂O₄₂, X₂M₁₇O_m, XM₆O_m
In the formula, X represents an element such as B, Si, P, C, Al, or N. M represents an element such as Mo, W, V, Nb, Ta, Cr, or U. m shows the integer of 15-80. Preferred X is an element such as B, Si, or P, and preferred M is an element such as Mo, W, or V. Note that M is not limited to one kind of element, and may be two or more kinds of elements.
m can be selected from the range of about 15 to 80 depending on the valences of M and X._TenO_mIn the case of a heteropolyacid anion represented by₂M₁₇O_mIn the case of a heteropolyacid anion represented by₆O_mIn the case of the heteropolyacid anion represented by
[0012]
The preferred heteropolyacid anion composition is XM₁₂O₄₀Can be expressed as In this composition formula, X is an element such as Si or P, and M is an element such as Mo, W, or V. Examples of the heteropolyacid anion having such a composition include anions of phosphomolybdic acid, phosphotungstic acid, silicomolybdic acid, silicotungstic acid, and phosphovanadomolybdic acid. Particularly preferred heteropolyacid anions are those of phosphomolybdic acid, phosphovanadmolybdate, and phosphovanadotungstic acid, and among them, phosphovanadomolybdate anion is preferred.
[0013]
The heteropolyacid exhibits sufficiently high activity as a free heteropolyacid, but at least a part of the hydrogen atoms corresponding to the cation of the heteropolyacid can be substituted with another cation and used as a salt of the heteropolyacid. By using a salt of a heteropolyacid, for example, it may be insolubilized, stability and heat resistance may be improved, and usefulness may be increased as a catalyst. The substitutable cation is not particularly limited, and examples thereof include ammonium (NH_FourEtc.), alkali metals (Cs, Rb, K, Na, Li, etc.), alkaline earth metals (Ba, Sr, Ca, Mg, etc.) and the like. In particular, some of the hydrogen atoms of the heteropolyacid are replaced with NH._FourTo replace the cation with H and NH._FourWhen both are configured, the catalytic activity and stability are further improved. In this case, NH for H_FourThe percentage of NH_Four/ H (molar ratio) = 0.1-10, preferably 0.2-8, more preferably about 0.3-5.
The heteropolyacid and the salt thereof may be used alone or in combination of two or more. A heteropolyacid or a salt thereof can be prepared by a conventional method.
[0014]
Among the heteropolyacids or salts thereof, phosphovanadomolybdic acid or a salt thereof represented by the following formula is preferably used.
A_{3 + n}[PV_nMo_12-nO₄₀]
(In the formula, A represents a heteropolyacid cation, and n is an integer of 1 to 10)
Examples of the cation represented by A include the above-mentioned cation in addition to a hydrogen atom. The value of n can be appropriately selected in consideration of oxidizing power and stability, and is preferably 4 to 10 (for example, 4 to 8), more preferably about 5 to 8. Heteropolyacid cations are replaced with H and other cations (eg NH_FourEtc.), the value of n is often about 4-10.
[0015]
Further, preferred heteropolyacids or salts thereof include phosphovanad molybdenum whose average atomic ratio of N, P, Mo and V is N / P / Mo / V = 1 to 12/1/2 to 8/4 to 10 A mixture of an acid or its ammonium salt is included. The average atomic ratio is preferably N / P / Mo / V = 2 to 10/1 / 2.5 to 7/5 to 9.5, and more preferably N / P / Mo / V = 3. It is-8/1/3-5/6-9. Such a heteropolyacid or a salt thereof is obtained by, for example, reacting a metavanadate such as sodium metavanadate with a molybdate such as sodium molybdate and phosphoric acid, and then adding an ammonium salt such as ammonium chloride. Can be prepared. The average atomic ratio of N, P, Mo and V can be controlled, for example, by adjusting the amount of the metavanadate, molybdate, phosphoric acid and ammonium salt used.
[0016]
  [Activated carbon]
  The activated carbon usually contains various impurities such as chlorine, silicon, aluminum, phosphorus, sulfur, potassium, calcium, iron, titanium, sodium, and magnesium depending on the raw materials and production conditions.
  As a result of studying the relationship between impurities in activated carbon used as a catalyst support and the catalytic activity of the present oxidation catalyst, the present inventor has found that the sulfur (S) content in the activated carbon greatly affects the catalytic activity. It was. That is, the main feature of the oxidation catalyst of the present invention is that at least one of the two catalyst components (A) and (B) constituting the oxidation catalyst has a sulfur (S) content of 0 to 0.0.07It is in the point which is supported by activated carbon of weight%.
[0017]
  When the sulfur content contained in the activated carbon exceeds 0.15% by weight, the catalytic activity is significantly reduced. Sulfur content in activated carbonIs 0It is -0.07 weight%, and it is so desirable that there is little.
[0018]
The content of other impurities in the activated carbon is as follows. That is, the content of chlorine (Cl) in the activated carbon is usually about 0 to 1% by weight, preferably 0 to 0.5% by weight, more preferably 0 to 0.3% by weight, particularly preferably 0. About 0.1% by weight. The content of silicon (Si) is usually about 0 to 8% by weight, preferably 0 to 1% by weight, more preferably 0 to 0.2% by weight, particularly preferably about 0 to 0.1% by weight. It is. The content of aluminum (Al) is usually about 0 to 3% by weight, preferably 0 to 0.5% by weight, more preferably about 0 to 0.01% by weight, and particularly 0 to 0.0. It is preferably about 005% by weight. The smaller the content of chlorine, silicon, and aluminum, the better.
[0019]
  As activated carbon, plant-based, mineral-based, polymer-basedNoharaActivated carbonIs mentioned.Plant-based raw materials include wood shells, sawdust, charcoal, bare ash, coconut shells and walnut shells and their carbides, fruit seeds, lignin, pulp production by-products, sugar waste, molasses and their carbides. included. Mineral raw materials include peat, grass charcoal, lignite (lignite, lignite), lemon bituminous coal, anthracite, coke, coal tar, petroleum, coal pitch, petroleum distillation residue, petroleum pitch, and the like. Polymeric raw materials include thermosetting resins such as phenol resins, furan resins, and epoxy resins; thermoplastic resins such as acrylic resins, polyacrylonitrile, and vinylidene chloride resins; rayon; and cellulose. Preferred activated carbon includes activated carbon obtained from plant-based materials (for example, plant husks such as coconut shells and carbides thereof) and polymer-based materials (for example, synthetic resins such as phenol resins and epoxy resins). In particular, when activated carbon obtained from a polymer-based raw material is used, the catalytic activity is remarkably improved. Activated carbon obtained from plant-based materials and polymer-based materials (especially polymer materials) often has a low content of sulfur, chlorine, silicon, and aluminum.In the present invention, activated carbon obtained from a polymer-based raw material is used.
[0020]
Activated carbon is generally obtained by carbonizing and sizing raw materials into water vapor, air (oxygen) and combustion gas (CO₂) Or a chemical activation method in which a raw material is impregnated with an aqueous zinc chloride solution and fired. The activated carbon in the present invention may be produced by any of the above methods. The shape of the activated carbon is not particularly limited, and may be any shape such as powder, granule, fiber, pellet, and honeycomb.
[0021]
The average pore diameter of the activated carbon may be in a range that does not impair the catalytic activity, and is, for example, about 8 to 100 angstrom, preferably about 8 to 60 angstrom. When activated carbon having an average pore diameter of about 30 to 60 angstroms is used, excellent activity is often obtained. If the average pore diameter is too small, the catalyst activity tends to decrease, and conversely if too large, the catalyst life tends to decrease.
The pore volume of the activated carbon (pore volume of pores having a pore diameter of less than 200 angstroms) is usually about 0.2 to 2.5 ml / g, but preferably 0.7 to 2.5 ml from the viewpoint of catalytic activity. / G, more preferably about 0.8 to 2.0 ml / g (for example, 0.8 to 1.5 ml / g).
The specific surface area of activated carbon is usually 500 to 4000 m.²/ G, but preferably 1000-4000m²/ G, with a specific surface area of 2000 to 4000 m.²/ G (for example, 2000 to 3000 m²/ G), a higher catalytic activity can be obtained.
[0022]
Only one of the two kinds of catalyst components may be supported on the activated carbon, or both components may be supported. When both components are carried on activated carbon, two catalyst components may be carried on the same activated carbon, or activated carbon carrying each catalyst component may be mixed. That is, the oxidation catalyst according to the present invention includes (i) an embodiment in which the divalent palladium compound (A) is supported on the activated carbon, (ii) an embodiment in which the heteropolyacid or a salt thereof (B) is supported on the activated carbon, (Iii) A mode in which activated carbon carrying a divalent palladium compound (A) and activated carbon carrying a heteropolyacid or a salt thereof (B) are used as a mixture, and (iv) divalent palladium on the same activated carbon. There is an embodiment in which the compound (A) and the heteropolyacid or salt (B) are supported. Especially, the aspect of said (ii) and (iv), especially (iv) the aspect which carry | supported the bivalent palladium compound (A) and heteropoly acid or its salt (B) on the same activated carbon is preferable.
[0023]
The total supported amount of the catalyst component is usually 0.5 to 80% by weight, preferably 1 to 40% by weight, and more preferably about 2 to 20% by weight with respect to the activated carbon.
The catalyst component can be supported by a conventional method, for example, an impregnation method, a coating method, a spray method, an adsorption method, a precipitation method, or the like. In addition, after carrying | supporting a catalyst component on activated carbon, according to the kind of reactor, reaction mode, etc., a catalyst can also be shape | molded in a suitable shape, for example, spherical shape, cylindrical shape, polygonal column shape, honeycomb shape, etc.
[0024]
[Other catalyst components]
The oxidation catalyst of the present invention may contain other catalyst components in addition to the divalent palladium compound (A) and the heteropolyacid or salt (B). Examples of such a catalyst component include dioxybenzenes or oxidants thereof (C) and protonic acids (D). When these catalyst components are used in combination, the oxidation reaction may be promoted depending on the organic substrate and the type of reaction.
[0025]
Dioxybenzenes or oxidants thereof (C) are particularly useful when the oxidation catalyst of the present invention is used, for example, in the acyloxylation reaction (iii) described later. Dioxybenzenes or oxidants thereof (C) are presumed to act as redox agents in the oxidation cycle. The dioxybenzenes (C) include dioxybenzene which may have a substituent, and equivalents of the dioxybenzene in a dioxybenzene / benzoquinone-redox system. Dioxybenzene includes dioxypolyphenyl compounds in which two hydroxyl groups are bonded to different benzene rings in addition to compounds in which two hydroxyl groups are bonded to one benzene ring. Examples of the dioxybenzene include hydroquinone (p-dioxybenzene), catechol (o-dioxybenzene), dioxybiphenyl, and the like.
[0026]
Examples of the substituent that dioxybenzene may have include a halogen atom such as fluorine, chlorine and bromine; a cyano group; a nitro group; and an alkyl group such as methyl, ethyl, isopropyl and t-butyl (preferably having a carbon number Alkyl group having about 1 to 4); haloalkyl group such as trifluoromethyl (preferably haloalkyl group having about 1 to 4 carbon atoms); hydroxyl group; alkoxy group such as methoxy and ethoxy (preferably having 1 to 4 carbon atoms) An aryloxy group such as phenoxy; a mercapto group; an alkylthio group such as methylthio and ethylthio (preferably an alkylthio group having about 1 to 4 carbon atoms); an arylthio group such as phenylthio; an acyl such as acetyl and benzoyl; Group (preferably an acyl group having about 1 to 10 carbon atoms); carboxyl group Substituted oxycarbonyl groups such as methoxycarbonyl, ethoxycarbonyl, and phenyloxycarbonyl (preferably substituted oxycarbonyl groups having about 2 to 11 carbon atoms); substituted or unsubstituted amino groups; aryl groups such as phenyl and naphthyl . In addition, the dioxybenzene having a substituent includes a condensed ring compound in which a benzene ring of dioxybenzene and a carbon ring or a heterocycle such as a benzene ring are condensed.
[0027]
The equivalent of dioxybenzene in the dioxybenzene / benzoquinone-redox system means an analog of dioxybenzene that can be converted to benzoquinone under oxidation reaction conditions. Examples of such dioxybenzene analogs include dioxybenzene monoalkyl ethers such as hydroquinone monomethyl ether; dioxybenzene dialkyl ethers such as hydroquinone dimethyl ether; aminophenols; diaminobenzenes and the like. These compounds may also have the substituent. These dioxybenzene analogs are usually converted to benzoquinone by oxidation under acidic conditions.
[0028]
Preferred dioxybenzenes (C) include hydroquinone, such as hydroquinone and chlorohydroquinone, which may have a substituent (for example, halogen atom, alkyl group, alkoxy group, cyano group, etc.).
[0029]
The oxidized form of the dioxybenzenes means an oxidized form corresponding to the dioxybenzenes constituting a dioxybenzene / benzoquinone-redox system under oxidation reaction conditions. Examples of the oxidant include P-benzoquinone (corresponding to hydroquinone), o-benzoquinone (corresponding to catechol), chlorobenzoquinone (corresponding to chlorohydroquinone) and the like.
Dioxybenzenes or oxidants thereof (C) can be used alone or in admixture of two or more.
[0030]
In addition, the oxidation catalyst of this invention shows high oxidation activity even if it does not contain dioxybenzenes or its oxidant (C). In particular, when the oxidation catalyst of the present invention is used in the Wacker-type reaction (i) described later, it is an oxidation product in a high yield without using dioxybenzenes or their oxidants (C). Ketones can be obtained.
[0031]
The protonic acid (D) is particularly useful when the oxidation catalyst of the present invention is used in, for example, a Wacker-type reaction (i) or an alkene acetalization reaction (ii) described later.
[0032]
The protonic acid (D) includes inorganic acids and organic acids. Examples of the inorganic acid include sulfuric acid, nitric acid, hydrogen halide (hydrogen fluoride, hydrogen chloride, hydrogen bromide, hydrogen iodide, and corresponding hydrohalic acid), phosphoric acid, boric acid, and the like. Organic acids include aliphatic carboxylic acids (eg, alkanoic acids such as formic acid and acetic acid; haloalkanoic acids such as monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, trifluoroacetic acid and pentafluoropropionic acid), and alicyclic carboxylic acids ( For example, carboxylic acid such as cyclohexane carboxylic acid, aromatic carboxylic acid such as benzoic acid, etc .; alkyl sulfonic acid such as methane sulfonic acid and ethane sulfonic acid, haloalkyl sulfonic acid such as trifluoromethane sulfonic acid And sulfonic acids such as aryl sulfonic acids (for example, benzene sulfonic acid, p-toluene sulfonic acid, naphthalene sulfonic acid, etc.). As the protonic acid (D), a cation exchange resin (for example, a strongly acidic ion exchange resin such as a sulfonic acid type ion exchange resin) can be used.
[0033]
Preferred protonic acids (D) include, for example, inorganic acids such as sulfuric acid, nitric acid, hydrogen halide (including hydrohalic acid), phosphoric acid; sulfonic acids such as alkylsulfonic acid, haloalkylsulfonic acid, arylsulfonic acid; And haloalkanoic acids such as trichloroacetic acid. The said protonic acid (D) may be used independently and may be used in combination of 2 or more type.
[0034]
[Oxidation method]
In the oxidation method of the present invention, the organic substrate is oxidized with molecular oxygen in the presence of the oxidation catalyst.
Examples of the organic substrate include non-aromatic unsaturated compounds such as alkenes and cycloalkenes.
[0035]
Examples of alkenes include ethene, propene, 1-butene, 2-butene, 1-pentene, 2-pentene, 3-methyl-1-butene, 1-hexene, 2-hexene, 3-hexene, 1-heptene, 2 -Linear or branched carbon such as heptene, 1-octene, 2-octene, 1-decene, 1-undecene, 1-tetradecene, 1-hexadecene, 1-octadecene, 1-icocene, 1-triacontene Alkenes having a number of about 1 to 30 (preferably about 2 to 20) are listed. Alkenes also include alkapolyenes (for example, alkadienes such as butadiene).
[0036]
Examples of the cycloalkene include cycloalkene having about 3 to 30 carbon atoms such as cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclododecene, and cyclooctadecene. Cycloalkenes also include cycloalkapolyenes such as cycloalkadienes.
[0037]
These compounds may have various substituents in the molecule. Examples of such substituents include halogen atoms, hydroxyl groups, substituted oxy groups (for example, alkoxy groups, cycloalkyloxy groups, aryloxy groups, acyloxy groups, silyloxy groups, etc.), mercapto groups, substituted thio groups (for example, Alkylthio group, cycloalkylthio group, arylthio group, etc.), carboxyl group, substituted oxycarbonyl group (eg, alkyloxycarbonyl group, aryloxycarbonyl group, etc.), substituted or unsubstituted carbamoyl group, cyano group, acyl group, formyl group, Examples thereof include a nitro group, a substituted or unsubstituted amino group, a cycloalkyl group, a cycloalkenyl group, an aryl group, and a heterocyclic group.
Specific examples of the alkene having a substituent include, for example, styrene derivatives such as styrene and methylstyrene; α, β-unsaturated esters such as ethyl acrylate; α, β-unsaturated nitriles such as acrylonitrile; α, such as acrolein; β-unsaturated aldehydes; α, β-unsaturated acetals such as acrolein diethyl acetal; α, β-unsaturated ketones such as vinyl methyl ketone.
[0038]
The molecular oxygen used for the oxidation of the organic substrate is not particularly limited, and pure oxygen may be used, or oxygen or air diluted with an inert gas such as nitrogen, helium, or argon may be used.
The amount of molecular oxygen used can be selected according to the type of organic substrate, and is usually 0.5 mol or more (for example, 1 mol or more), preferably 1 to 100 mol, and more preferably 1 to 100 mol, based on 1 mol of the organic substrate. Preferably it is about 1-50 mol. In many cases, a molar excess of molecular oxygen is used relative to the organic substrate.
[0039]
The usage-amount of a bivalent palladium compound (A) is 0.001-1 mol with respect to 1 mol of organic substrates, for example, Preferably it is 0.01-0.5 mol, More preferably, it is 0.02-0. About 2 moles. The usage-amount of heteropolyacid or its salt (B) is 0.0001-1 mol with respect to 1 mol of organic substrates, for example, Preferably it is 0.001-0.1 mol, More preferably, it is 0.002-0. About 05 moles. When dioxybenzenes (C) are used, the amount used is, for example, 0.001 to 1 mol, preferably 0.005 to 0.6 mol, more preferably 0.01 to 1 mol of the organic substrate. About 0.4 mol. When the protonic acid (D) is used, the amount used is, for example, 0.001 to 1 mol, preferably 0.01 to 0.5 mol, more preferably 0.05 to 1 mol, relative to 1 mol of the organic substrate. About 0.3 mol.
[0040]
The reaction may be performed in the presence or absence of a solvent. The solvent can be appropriately selected depending on the type of organic substrate and target product. Examples of the solvent include aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as hexane, heptane, and octane; alicyclic hydrocarbons such as cyclohexane; carbon tetrachloride, chloroform, dichloromethane, 1, 2 -Halogenated hydrocarbons such as dichloroethane; Carboxylic acids such as acetic acid, propionic acid and butyric acid; Ketones such as acetone and methyl ethyl ketone; Esters such as methyl acetate, ethyl acetate, isopropyl acetate and butyl acetate; N, N-dimethylformamide, N Amides such as N, N-dimethylacetamide; Nitriles such as acetonitrile, propionitrile and benzonitrile; Linear or cyclic ethers such as diethyl ether, dibutyl ether, dimethoxyethane, dioxane and tetrahydrofuran; , Ethanol, alcohols such as isopropanol. These solvents are used alone or in combination of two or more.
[0041]
The reaction temperature can be appropriately selected in consideration of the reaction rate and reaction selectivity according to the organic substrate and the type of reaction, and is, for example, about 0 to 200 ° C., preferably about 10 to 100 ° C. The reaction may be carried out at normal pressure or under pressure. The reaction may be performed by any method such as a batch method, a semi-batch method, or a continuous method.
[0042]
The oxidation method of the present invention includes, for example, (i) a Wacker-type reaction that generates a corresponding ketone from an alkene or cycloalkene, (ii) an acetalization reaction that generates a corresponding acetal compound from the alkene, and (iii) an alkene or cyclo The present invention can be applied to various reactions such as an acyloxylation reaction of an alkene (eg, acetoxylation reaction).
[0043]
Wacker type reaction (i) is carried out in the presence of water. In this reaction, when an alkene is used as an organic substrate, a corresponding oxoalkane (aliphatic ketone) is produced. In addition, when a terminal olefin is used among alkenes, the corresponding methyl ketone will be obtained. More specifically, methyl octyl ketone and acetophenone are produced from 1-decene and styrene, respectively. In addition, when cycloalkene is used as the organic substrate, cycloalkenone is produced depending on the corresponding cycloalkanone and reaction conditions. For example, from cyclohexene, cyclohexanone and cyclohexenone can be obtained depending on conditions.
[0044]
The amount of water may be a catalytic amount or may be present in an excess molar amount relative to the organic substrate. For example, the usage-amount of water is 0.1-1000 mol with respect to 1 mol of organic substrates, Preferably it is about 1-100 mol. In this reaction, in order to accelerate the reaction, the proton acid (D) is usually present in the system in many cases.
[0045]
The acetalization reaction (ii) is performed in the presence of an alcohol. In this reaction, a terminal olefin in which an electron withdrawing group (for example, an alkoxycarbonyl group, a cyano group, a formyl group, an acetal group, an acyl group, etc.) is bonded to a carbon atom constituting a double bond is usually used as an organic substrate. A compound in which the carbon atom adjacent to the carbon atom to which the electron withdrawing group is bonded is acetalized is generated. Specifically, when ethyl acrylate, acrylonitrile, acrolein and acrolein diethyl acetal are oxidized in the presence of ethanol, ethyl 3,3-diethoxypropionate, 3,3-diethoxypropionitrile, 1,1 respectively. , 3,3-tetraethoxypropane and 1,1,3,3-tetraethoxypropane are produced.
[0046]
Examples of the alcohol include monohydric alcohols such as methanol and ethanol; dihydric alcohols such as propylene glycol. The amount of alcohol used is usually 2 mol or more in the case of monohydric alcohol and 1 mol or more in the case of dihydric alcohol with respect to 1 mol of the organic substrate. Alcohol is often used in excess with respect to the organic substrate, and can also be used as a reaction solvent.
Also in this case, a protonic acid (D) may be present in the system in order to increase the reaction rate.
[0047]
The acyloxylation reaction (iii) is usually performed in the presence of a carboxylic acid and a base. In this reaction, an unsaturated compound in which an acyloxy group corresponding to the carboxylic acid is introduced at the allylic position is produced from an alkene or cycloalkene. Specifically, for example, when cyclopentene is oxidized in the presence of acetic acid and a base, 1-acetoxy-2-cyclopentene is produced. Further, when 1,3-alkadiene is used as the organic substrate, 1,4-diacyloxy-2-alkene is produced. For example, 1,4-diacetoxy-2-butene is obtained when butadiene is oxidized in the presence of acetic acid and a base.
[0048]
Examples of the carboxylic acid include aliphatic, alicyclic or aromatic carboxylic acids such as formic acid, acetic acid, propionic acid, acrylic acid, cyclohexanecarboxylic acid, and benzoic acid. Examples of the base include hydroxides, carbonates, hydrogen carbonates of alkali metals (for example, sodium and potassium), inorganic bases such as hydroxides and carbonates of alkaline earth metals (for example, magnesium, calcium, etc.) And organic bases such as triethylamine and pyridine are included. Instead of adding carboxylic acid and base separately, a salt of carboxylic acid and base may be added into the system.
The amount of carboxylic acid used is usually 1 mol or more relative to the organic substrate. Carboxylic acid can also be used as a reaction solvent. The usage-amount of a base is 0.01-1 mol with respect to 1 mol of organic substrates, Preferably it is about 0.05-0.5 mol.
[0049]
Oxidation products produced by the reaction can be easily separated and purified by conventional separation means, for example, separation means such as filtration, concentration, distillation, extraction, crystallization, recrystallization, column chromatography, or a combination thereof. .
The oxidation catalyst of the present invention has an extremely high catalytic activity because the catalyst component is supported on activated carbon having a low sulfur content. For example, a mild ketone is removed from an organic substrate such as an alkene or cycloalkene. Under the conditions, it can be efficiently produced in a high yield. Therefore, it is extremely useful as an industrial oxidation catalyst.
[0050]
【The invention's effect】
According to the oxidation catalyst and oxidation method of the present invention, an organic substrate can be efficiently oxidized.
Further, according to the production method of the present invention, the corresponding ketone can be obtained from cycloalkene or alkene with high yield.
[0051]
【Example】
Hereinafter, the present invention will be described in more detail based on examples, but the present invention is not limited to these examples.
Preparation Example 1
NaVO_Three(7.32 g, 60 mmol) in aqueous solution (water: 38 ml)₂MoO_Four・ 2H₂An aqueous solution of O (8.22 g, 34 mmol) (water: 12 ml) was added. A solution obtained by dissolving 85% phosphoric acid (7.6 g, 66 mmol) in water (10 ml) was added to the obtained aqueous solution, and the mixture was stirred at 95 ° C. for 1 hour. After cooling the mixed solution to 0 ° C., 150 ml of a saturated aqueous ammonium chloride solution was added to obtain a brown precipitate. The precipitate was filtered off and recrystallized from water. When the crystal was analyzed, the average atomic ratio of N, P, Mo, and V was N / P / Mo / V = 5.0 / 1.0 / 4.0 / 7.8, and some of the protons were It was found to be a mixture of phosphovanadomolybdate substituted with an ammonium cation (hereinafter abbreviated as NPMoV).
Pd (OAc)₂(0.44 g) was dissolved in acetone (150 ml), and activated carbon A (Kuraray Coal BP-25, manufactured by Kuraray Chemical Co., Ltd.); specific surface area 2420 m²/ G; pore volume 1.20 ml / g; average pore diameter 8-24 angstrom; specific gravity 0.264; pH value 7; benzene adsorption power 90% by weight; methylene blue decoloring power 380 ml / g; chlorine content 0.092 weight 10.26 g of silicon content 0.03% by weight; aluminum content 1 ppm or less; sulfur content 0.04% by weight; particle size 8-24 mesh; raw material: phenol resin). After stirring overnight at room temperature, Pd (OAc)₂/ C was filtered off and dried at 60 ° C. under reduced pressure. This Pd (OAc)₂/ C (10.7 g) was suspended in 150 ml of water, NPMoV (0.7 g) obtained above was added thereto, and the mixture was vigorously stirred at room temperature for 30 minutes. The solid was filtered off, washed with water, and dried at 90 ° C. under reduced pressure to give [Pd (OAc)₂-NPMoV] / C was obtained almost quantitatively. Pd (OAc)₂And NPMoV loadings were 4.1 wt% and 6.3 wt%, respectively.
[0052]
Preparation Example 2
As activated carbon, activated carbon B (manufactured by Wako Pure Chemical Industries, Ltd .; specific surface area 1450 m)²Pore volume of 0.58 ml / g; average pore diameter of 15 to 25 angstroms; specific gravity of 0.53; chlorine content of 0.091 wt%; silicon content of 0.28 wt%; aluminum content of 500 ppm; [Pd (OAc)] in the same manner as in Preparation Example 1 except that 0.18% by weight; particle size 10 to 32 mesh; raw material: coconut shell; activation method: chemical) was used.₂-NPMoV] / C was prepared.
[0053]
Preparation Example 3
As the activated carbon, activated carbon C (Starcoal W-AC, manufactured by Kita Carsei Co., Ltd .; specific surface area 1100 m²/ G; pore volume 0.7 ml / g; average pore diameter 30 angstroms; specific gravity 0.38 to 0.42; pH value 5.5; benzene adsorption power 30% by weight; methylene blue decoloring power 120 ml / g; chlorine content 0.049 wt%; silicon content 0.01 wt%; aluminum content 1000 ppm; sulfur content 0.22 wt%; particle size 8 to 32 mesh; raw material: coal-based) and Preparation Example 1 Similarly, [Pd (OAc)₂-NPMoV] / C was prepared.
[0054]
Preparation Example 4
[Pd (OAc)] in the same manner as in Preparation Example 1 except that silica gel was used instead of activated carbon.₂-NPMoV] / SiO₂Was prepared.
[0055]
Preparation Example 5
[Pd (OAc)] in the same manner as in Preparation Example 1 except that alumina was used instead of activated carbon.₂-NPMoV] / Al₂O_ThreeWas prepared.
[0056]
Example 1
Cyclopentene (2 mmol), prepared in Preparation Example 1 [Pd (OAc)₂-NPMoV] / C (490 mg), methanesulfonic acid (0.2 mmol), and ethanol / water (9.5 ml / 0.5 ml) were placed in a glass flask and the mixture was placed under an oxygen atmosphere (1 atm). The mixture was stirred at a temperature of 50 ° C. for 6 hours. The reaction mixture was cooled to room temperature, water (8 ml) was added, and the mixture was extracted 4 times with hexane (15 ml). The extract was neutralized with saturated aqueous sodium hydrogen carbonate solution and washed twice with water (15 ml). When the organic layer was concentrated and subjected to silica gel column chromatography, cyclopentanone and 2-cyclopenten-1-one were obtained. The yield of cyclopentanone was 93.2%, and the yield of 2-cyclopenten-1-one was 2.75%.
[0057]
Comparative Example 1
[Pd (OAc) prepared in Preparation Example 1₂[Pd (OAc) prepared in Preparation Example 2 instead of -NPMoV] / C₂The reaction was performed in the same manner as in Example 1 except that -NPMoV] / C was used. As a result, the yield of cyclopentanone was 13.5%, and the yield of 2-cyclopenten-1-one was 7.63%.
[0058]
Comparative Example 2
[Pd (OAc) prepared in Preparation Example 1₂[Pd (OAc) prepared in Preparation Example 3 instead of -NPMoV] / C₂The reaction was performed in the same manner as in Example 1 except that -NPMoV] / C was used. As a result, the yield of cyclopentanone was 8.70%, and the yield of 2-cyclopenten-1-one was 8.33%.
[0059]
Comparative Example 3
[Pd (OAc) prepared in Preparation Example 1₂[Pd (OAc) prepared in Preparation Example 4 instead of -NPMoV] / C₂-NPMoV] / SiO₂The same operation as in Example 1 was performed except that was used. As a result, the reaction did not proceed at all.
[0060]
Comparative Example 4
[Pd (OAc) prepared in Preparation Example 1₂[Pd (OAc) prepared in Preparation Example 5 instead of -NPMoV] / C₂-NPMoV] / Al₂O_ThreeThe same operation as in Example 1 was performed except that was used. As a result, the reaction did not proceed at all.
[0061]
Example 2
Butadiene (0.2 ml), prepared in Preparation Example 1 [Pd (OAc)₂-NPMoV] / C (490 mg), hydroquinone (0.4 mmol), sodium carbonate (0.5 mmol) and acetic acid (10 ml) are placed in a glass flask and the mixture is placed in an oxygen atmosphere (1 atm) at a temperature of 60 Stir at 20 ° C. for 20 hours. The reaction mixture was cooled to room temperature, water (8 ml) was added, and the mixture was extracted 4 times with hexane (15 ml). The extract was neutralized with saturated aqueous sodium hydrogen carbonate solution and washed twice with water (15 ml). The organic layer was concentrated and subjected to silica gel column chromatography to obtain 1,4-diacetoxy-2-butene in a yield of 42.7%.
[0062]
Comparative Example 5
[Pd (OAc) prepared in Preparation Example 1₂[Pd (OAc) prepared in Preparation Example 4 instead of -NPMoV] / C₂-NPMoV] / SiO₂The same operation as in Example 2 was performed except that was used. As a result, the reaction did not proceed at all.
[0063]
Comparative Example 6
[Pd (OAc) prepared in Preparation Example 1₂[Pd (OAc) prepared in Preparation Example 5 instead of -NPMoV] / C₂-NPMoV] / Al₂O_ThreeThe same operation as in Example 2 was performed except that was used. As a result, the reaction did not proceed at all.

Claims (7)

(A) a oxidizing catalyst comprising a divalent palladium compound (B) heteropoly acid or salt thereof, at least one of the catalyst components, sulfur (S) content of from 0 to 0.07 wt% of the polymer An oxidation catalyst supported on activated carbon obtained from a raw material .   The oxidation catalyst according to claim 1, wherein the heteropolyacid or a salt thereof (B) contains P and at least one element selected from V, Mo and W as constituent elements. The heteropolyacid or a salt thereof (B) is represented by the following formula:
A _{3 + n} [PV _n Mo _12-n O ₄₀ ]
(In the formula, A represents at least one selected from a hydrogen atom, NH4, alkali metal and alkaline earth metal, and n is an integer of 1 to 10).
The oxidation catalyst according to claim 1 or 2, which is phosphovanadomolybdic acid or a salt thereof.   Heteropolyacid or a salt thereof (B) is an average atomic ratio of N, P, Mo and V N / P / Mo / V = 1-12 / 1 / 2-8 / 4-10 phosphovanadomolybdic acid or ammonium thereof The oxidation catalyst according to claim 1 or 2, which is a mixture of salts.   An oxidation method for oxidizing an organic substrate with molecular oxygen in the presence of the oxidation catalyst according to claim 1.   6. The oxidation method according to claim 5, wherein the organic substrate is an alkene or a cycloalkene.   A method for producing a ketone, wherein an alkene or cycloalkene is oxidized with molecular oxygen in the presence of the oxidation catalyst according to claim 1 to produce a corresponding ketone.