JP2009215199A - Process for preparing ketone compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process for efficiently producing a ketone compound from an olefin compound, oxygen, and water. <P>SOLUTION: The method for preparing a carbonyl compound comprises reacting an olefin with a molecular oxygen in the presence of an effective amount of proton, palladium, an ammonium salt of an isopolyacid, an iron compound in a solvent containing water. For example, cyclohexanone can be obtained by reacting cyclohexene with air in a mixed solvent of acetonitrile and water in the presence of (NH<SB>4</SB>)<SB>6</SB>[Mo<SB>7</SB>O<SB>24</SB>] of an ammonium salt of an isopolyacid and iron alum. A high ketone yield can be obtained by using an easily available ammonium salt of an isopolyacid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

The present invention relates to a method for producing a corresponding carbonyl compound by oxidizing an olefin.

As a method for producing a carbonyl compound by direct oxidation of olefins, a Wacker method using a PdCl ₂ -CuCl ₂ catalyst has been known for a long time. However, this Wacker method has problems such as corrosion of the apparatus by chlorine and by-product of chlorine compounds. In addition, there is a problem that the reaction rate is remarkably reduced as the carbon number of the raw material olefin increases, and the reactivity of the internal olefin is low, and industrially, other than the production of lower carbonyl compounds such as acetaldehyde and acetone. Not used. As a method for solving such a problem, Patent Document 1 discloses a method of performing a reaction by adding a redox metal in the presence of palladium and a heteropolyacid.

Patent Document 1 Patent Application Publication 63-500923

However, the method disclosed in Patent Document 1 has a low activity per Pd and is not satisfactory from the viewpoint of productivity. In addition, there is a problem in terms of obtaining and handling the catalyst, such as the necessity of synthesizing the heteropolyacid in a multi-step process, and the necessity of using a potassium salt for isolation.

That is, the present invention relates to a carbonyl compound characterized by reacting an olefin with molecular oxygen in a solvent containing water in the presence of an effective amount of proton and palladium, an ammonium salt of isopolyacid, and an iron compound. It relates to a manufacturing method.

According to the present invention, a high ketone yield can be obtained by using an easily available ammonium salt of isopolyacid.

Examples of the palladium source that can be used in the present invention include palladium metal, palladium compounds, and mixtures thereof. Specific examples of the palladium compound include an organic acid salt of palladium, an oxyacid salt of palladium, palladium oxide, and palladium sulfide. Moreover, these salts and oxides, organic complexes or inorganic complexes of sulfides, and mixtures thereof can be mentioned. Examples of the organic acid salt of palladium include, for example, palladium acetate and palladium cyanide. Examples of the oxyacid salt of palladium include, for example, palladium nitrate and palladium sulfate. Examples of organic or inorganic complexes of these salts, oxides, and sulfides include, for example, tetraamine palladium (II) nitrate, bis (acetylacetonate) palladium, and the like. Among these, an organic acid salt of palladium or an oxyacid salt of palladium is preferable, and palladium acetate is more preferable. In particular, when oxidizing cyclohexene, it is desirable that the palladium source does not contain chlorine.

In this specification, the ammonium salt of isopolyacid means an anion portion of a condensation product of oxygen acid containing one or more kinds of metal components and an isopolyacid salt in which part or all of the counter cation is an ammonium ion. To do.
As an ammonium salt of isopolyacid, for example, one kind of oxygen acid ion such as Mo, W, V, Nb or Ta (specifically, for example, molybdic acid, tungstic acid, vanadic acid, niobic acid, tantalic acid, etc.) The ammonium salt of the isopoly acid contained above can be mentioned. The ammonium salt of an isopolyacid that can be used in the present invention is not particularly limited, but a preferred ammonium salt of an isopolyacid is an ammonium salt of an isopolyacid composed of one kind of metal element. The general formula of the isopolyanion is [M _y O _z ] ^x- (wherein M represents one element selected from Mo, W, V, Nb and Ta, and x, y and z are 1). Represents the above integers).
More specifically, for example, in the case of isopolymolybdic acid, [Mo ₂ O ₇ ] ²⁻ , [Mo ₃ O ₁₀ ] ²⁻ , [Mo ₅ O ₁₇ ] ⁴⁻ , [Mo ₆ O ₁₉ ] ²⁻ , [Mo ₇ O ₂₄ ] ⁶⁻ , [Mo ₈ O ₂₇ ] ⁶⁻ , [Mo ₁₀ O ₃₄ ] ⁸⁻ , [Mo ₃₆ O ₁₁₂ ] ^{8−, and the} like. A particularly preferred ammonium salt of isopolymolybdic acid is (NH ₄ ) ₆ [Mo ₇ O ₂₄ ] because of its availability. The aforementioned ammonium salt of isopolyacid may contain crystal water.
The amount of isopolyacid ammonium salt used varies depending on the type of solvent used and the reaction conditions, and cannot be specified unconditionally, but when using an organic solvent containing water (typically acetonitrile containing water). Is preferably added in an amount such that the concentration of the ammonium salt of isopolyacid is 0.1 mmol / L to 100 mmol / L, more preferably in the range of 1 mmol / L to 50 mml / L. Moreover, the usage-amount of the ammonium salt of isopolyacid is 50-0.1 mol normally with respect to 1 mol of palladium, Preferably it is 20-0.5 mol, More preferably, it is 1-10 mol.

In the method of the present invention, an iron compound is added to carry out the reaction. Known compounds can be used as the iron compound. For example, inorganic salts such as iron sulfate, alum iron (iron ammonium sulfate), iron nitrate, and iron phosphate, and organic acid salts such as iron citrate and iron acetate , Phthalocyanine iron, acetylacetonate iron and other complexes, and iron oxide. Among these, inorganic salts are preferably used, and iron sulfate and alum iron are preferable. Instead of using an iron compound, an ammonium salt of an isopolyacid containing iron can also be used. For example, as in the literature (Polyhedron, 6 (2), p213-218, 1987), it is possible to perform an appropriate treatment with an iron compound and an ammonium salt of isopolyacid, and add the resulting solid to the reaction system. . A suitable iron concentration is 0.01 to 100 mol, more preferably 0.1 to 50 mol, per 1 mol of isopolyacid.

The reaction of the present invention is usually carried out in a liquid phase, and an inert organic solvent is usually used as a reaction solvent. Examples of the inert organic solvent include, for example, nitrile compounds (eg, acetonitrile, propionitrile, benzonitrile, etc.), alcohols (eg, methanol, ethanol, isopropanol, etc.), and ethers (1,4-dioxane, tetrahydrofuran, etc.) ) And other organic solvents. Usually, a polar organic solvent is preferably used, and acetonitrile is more preferable. Moreover, as a solvent, the above-mentioned compound may be used independently and may be used as a mixture.
In the present invention, the ratio of water contained in the solvent varies depending on the type of isopolyacid used and the reaction conditions, and thus cannot be defined unconditionally, but is preferably 50% by volume or less, and particularly preferably 5 to 40% by volume. .

Although the olefin used in this invention is not restrict | limited, A cyclic ketone can be efficiently obtained especially by oxidizing a cyclic olefin. Examples of cyclic olefins include cyclic olefins having 4 to 20 carbon atoms. Examples include cyclobutene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclodecene, cyclododecene, cyclooctadecene, and the like. The cycloolefin used more preferably is cyclohexene, and cyclohexanone is efficiently produced from cyclohexene.

As molecular oxygen, pure oxygen or air can be used, and these gases may be used as a gas containing molecular oxygen by diluting with an inert gas such as nitrogen or helium. The amount of oxygen to be used is usually adjusted by the pressure of the oxygen-containing gas introduced into the reaction system. The oxygen partial pressure is preferably 0.01 to 10 MPa (gauge pressure), more preferably 0.05 to 5 MPa ( Set the gauge pressure range. The reaction gas may be introduced in its entirety before the reaction, or may be reacted while being continuously supplied by blowing it into the system during the reaction.

  In the reaction of the present invention, the proton may be provided by an isopolyacid or may be added to the reaction as a proton acid. Examples of the protonic acid include inorganic acids, organic acids, and solid acids. Examples of the inorganic acid include a binary acid (hydrogen acid) such as hydrofluoric acid, and an oxo acid (oxygen acid) such as sulfuric acid and nitric acid. Examples of the organic acid include formic acid, aliphatic carboxylic acid (for example, acetic acid), alicyclic carboxylic acid (for example, cyclohexane carboxylic acid), aromatic carboxylic acid (for example, benzoic acid), sulfonic acid and the like. Examples of the sulfonic acid include alkylsulfonic acid (for example, methanesulfonic acid or ethanesulfonic acid), arylsulfonic acid (for example, benzenesulfonic acid, p-toluenesulfonic acid, or naphthalenesulfonic acid). Examples of solid protonic acids include, for example, ion exchange resins (eg, sulfonic acid type ion exchange resins), acidic zeolites, and sulfated zirconia. In particular, sulfuric acid is preferred.

The effective amount of the proton described above varies depending on the olefin compound used and the amount and type of the solvent used, and is appropriately adjusted. For example, when the reaction is carried out in a liquid phase that is a two-phase system including an aqueous phase and an organic phase, the concentration of protons in the aqueous phase is preferably 10 ⁻⁵ to 10 mol / l, more preferably 10 ^{−3 to 1} mol. A proton may be added as a protonic acid so as to be / l. When the reaction is carried out in a homogeneous liquid phase formed from water and an organic solvent, it is assumed that if the added protonic acid and isopolyacid contain protons as counter cations, all of the contained protons are free. The proton concentration in the homogeneous liquid phase is preferably 10 ⁻⁵ to 10 mol / l, more preferably 10 ^{−3 to} 1 mol / l.

The reaction is usually performed in a temperature range of 0 to 200 ° C, preferably 10 to 150 ° C, more preferably 30 to 100 ° C. The reaction is usually carried out within a pressure range of 0.01 to 10 MPa (absolute pressure), preferably 0.05 to 7 MPa (absolute pressure), more preferably 0.1 to 5 MPa (absolute pressure). The reaction can be performed in a batch, semi-batch, continuous process, or combinations thereof. The catalyst may be preliminarily charged into the reactor before starting the reaction, or may be reacted while being continuously supplied. The reaction solution or reaction gas containing the product is collected and the desired ketone is isolated. The produced ketone compound is usually separated by distillation, phase separation or the like.

EXAMPLES Hereinafter, although an Example demonstrates this invention in detail, this invention is not limited to a following example.

Example 1
Cyclohexene 0.33 g (4 mmol), acetonitrile 4.3 ml, water 0.7 ml, sulfuric acid 0.04 g, Pd (OAc) ₂ 7 mg (0.03 mmol), AHM ((NH ₄ ) ₆ [Mo ₇ O ₂₄ ] · 4H ₂ O, Wako Pure Chemical) 6 mg (0.005 mmol), alum iron (FeNH ₄ (SO ₄ ) ₂ · 12H ₂ O, Kanto Chemical) 3 mg (0.005 mmol) in a 120 ml autoclave, air 2 MPa, N _The reaction was carried out at 323 K for 2 hours while stirring with a stirrer under ₂ MPa. Table 1 shows the results obtained by analyzing the obtained reaction mass by gas chromatography.

Example 2
A cyclohexene oxidation reaction was carried out in the same manner as in Example 1 except that 2 mg (0.008 mmol) of iron sulfate (FeSO ₄ · 7H ₂ O, Nacalai Tesque) was added instead of alum iron. The results are shown in Table 1.

Example 3
A cyclohexene oxidation reaction was carried out in the same manner as in Example 1 except that 1 mg (0.006 mmol) of iron oxide (Fe ₂ O ₃ , Kanto Chemical) was added instead of alum iron. The results are shown in Table 1.

Example 4
A cyclohexene oxidation reaction was carried out in the same manner as in Example 1 except that 4.6 ml of acetonitrile and 0.4 ml of water were used. The results are shown in Table 1.

Example 5
A cyclohexene oxidation reaction was carried out in the same manner as in Example 1 except that 3 ml of acetonitrile and 2 ml of water were used. The results are shown in Table 1.

Example 6
Alum iron and (NH ₄ ) ₆ [Mo ₇ O ₂₄ ] · 4H ₂ O were treated according to the method of the literature (Polyhedron, 6 (2), p213-218, 1987). AHM 5 g (4.2 mmol) was dissolved in 80 ml of water and heated to boiling. The solution which melt | dissolved alum iron 1.5g (3.1 mmol) in 20 ml of water was dripped there. Under heating, the solution was concentrated to half and filtered. The filtrate was further concentrated to give a solid. The solid was recrystallized with water. The obtained solid showed an infrared absorption spectrum similar to the literature. Hereinafter, it is expressed as Fe-AHM.

Example 7
A mixture of 0.33 g (4 mmol) of cyclohexene, 4.3 ml of acetonitrile, 0.7 ml of water, 0.04 g of sulfuric acid, 7 mg (0.03 mmol) of Pd (OAc) _{2 and} 7 mg of Fe-AHM was placed in a 120 ml autoclave, and 2 MPa of air, The mixture was reacted at 323 K for 2 hours while stirring with a stirrer under N ₂ 3 MPa. Table 1 shows the results obtained by analyzing the obtained reaction mass by gas chromatography.

Comparative Example 1
K ₅ H ₄ PMo ₆ V ₆ Mo ₄₀ was prepared according to the method disclosed in Patent Document 1. 7.38 g of sodium metavanadate was dissolved in 38 ml of distilled water and brought to 90 ° C. Separately, 8.07 g of sodium molybdate was added to 12 ml of distilled water and heated to 90 ° C., and the previously prepared aqueous sodium metavanadate was added. To this mixture was added 5 ml of 85% phosphoric acid. After cooling, 8 g of potassium nitrate was added and stirred, and then the solid was filtered. The solid was recrystallized from 0.25MH ₂ SO ₄ . Elemental analysis of the obtained solid was K ₅ H ₄ PMo ₆ V ₆ O ₄₀ .

Comparative Example 2
1.6 g (20 mmol) of cyclohexene, 3 ml of acetonitrile, 2 ml of water, 8.7 mg of sulfuric acid, Pd (OAc) ₂ 4 mg (0.02 mmol), 100 mg (0.06 mmol) of K ₅ H ₄ PMo ₆ V ₆ O ₄₀ , alum iron A mixture of 58 mg (0.12 mmol) was placed in a 120 ml autoclave and reacted at 323 K for 2 hours while stirring with a stirrer under ₂ MPa of air and 3 MPa of N ₂ . Table 1 shows the results obtained by analyzing the obtained reaction mass by gas chromatography.

Comparative Example 3
210 mg (2.6 mmol) of cyclohexene, 1.3 ml of acetonitrile, 3.8 ml of water, 7.7 mg of sulfuric acid, 8 mg (mmol) of Pd (NO ₃ ) _2, 160 mg (0.09 mmol) of K ₅ H ₄ PMo ₆ V ₆ O ₄₀ , Cu (NO ₃ ) ₂ .3H ₂ O (120 mg) was placed in a 120 ml autoclave and allowed to react at 323 K for 2 hours while stirring with a stirrer under ₂ MPa of air and 3 MPa of N ₂ . Table 1 shows the results obtained by analyzing the obtained reaction mass by gas chromatography.

ＴＯＦ／ｈ^−１：（生成物のモル数）／（Ｐｄのモル数）／（反応時間）
ＡＨＭ：（（ＮＨ_４）_６［Ｍｏ_７Ｏ_２４］・４Ｈ_２Ｏ）

TOF / h ⁻¹ : (number of moles of product) / (number of moles of Pd) / (reaction time)
AHM: ((NH ₄ ) ₆ [Mo ₇ O ₂₄ ] · 4H ₂ O)

Claims (7)

A method for producing a carbonyl compound, comprising reacting an olefin and molecular oxygen in a solvent containing water in the presence of an effective amount of protons and palladium, an ammonium salt of an isopolyacid, and an iron compound. The isopolyacid is represented by the formula [M _y O _z ] ^x- (wherein M represents one element selected from Mo, W, V, Nb, and Ta, and x, y, and z are integers of 1 or more) The production method according to claim 1, which is an isopolyacid having an anion represented by: The production method according to claim 1, wherein the isopolyacid is an ammonium salt represented by (NH ₄ ) ₆ [Mo ₇ O ₂₄ ]. The production method according to claim 1, wherein the reaction is performed in a mixed solvent of acetonitrile and water. The production method according to claim 1, wherein the proton source of an effective amount of protons is sulfuric acid. The production method according to any one of claims 1 to 5, wherein the olefin is a cyclic olefin, and the carbonyl compound produced is a cyclic ketone. The production method according to any one of claims 1 to 5, wherein the olefin is cyclohexene and the carbonyl compound to be produced is cyclohexanone.