JP2007238478A - Method for producing cycloalkanol and/or cycloalkanone - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To produce a cycloalkanol and/or cycloalkanone in high selectivity by oxidizing a cycloalkane in high conversion. <P>SOLUTION: The production method comprises the oxidation of a cycloalkane with molecular oxygen in the presence of a compound expressed by formula (1) (R<SP>1</SP>and R<SP>2</SP>are each a hydrocarbon group or R<SP>1</SP>and R<SP>2</SP>together with bonded carbon atom form a hydrocarbon ring; the part composed of parallel dotted line and solid line means a single bond or a double bond; X<SP>1</SP>to X<SP>8</SP>are each hydrogen atom, a halogen atom, nitro group, cyano group, a hydrocarbon group or sulfonyl group; and Y<SP>1</SP>and Y<SP>2</SP>are each hydrogen atom, nitro group, cyano group or a hydrocarbon group). <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing cycloalkanol and / or cycloalkanone by oxidizing cycloalkane with molecular oxygen.

  As one of the methods for oxidizing hydrocarbons such as alkanes, cycloalkanes and alkenes with molecular oxygen, a metal complex having salen [N, N′-bis (salicylidene) ethylenediamine and substituted derivatives thereof] as a ligand is used. A method for use in a catalyst has been proposed. As such a catalyst, for example, JP-A-1-180840 (patent document 1) discloses a complex of a transition metal of groups IV to VIII to which an azide or nitride is bonded, and JP-A-1-125337 ( Patent Document 2) discloses an iron complex to which an anion is bonded. In addition, US Pat. No. 5,347,057 (Patent Document 3) discloses a ruthenium complex having an oxo group bonded thereto, and WO 98/04538 (Patent Document 4) discloses an electron-withdrawing group. A trivalent metal complex in which is bound is disclosed.

Japanese Unexamined Patent Publication No. 1-180840 JP-A-1-125337 US Pat. No. 5,347,057 International Publication No. 98/04538 Pamphlet

  In the above conventional method, particularly when cycloalkane is oxidized with molecular oxygen to obtain cycloalkanol and / or cycloalkanone, the activity and selectivity of the catalyst, that is, the conversion rate of cycloalkane and cycloalkanol are obtained. And / or the selectivity of cycloalkanone was not always satisfactory. Therefore, an object of the present invention is a method of oxidizing cycloalkane with molecular oxygen using a metal complex having salen as a ligand as a catalyst, and oxidizing cycloalkane with a good conversion rate, The object is to provide a method capable of producing cycloalkanol and / or cycloalkanone with high selectivity.

  As a result of intensive studies, the present inventors have found that the above object can be achieved by using a cobalt complex having a predetermined salen as a ligand as a catalyst, and have completed the present invention. That is, the present invention provides the following formula (1):

(Wherein R ¹ and R ² each represent a hydrocarbon group, or R ¹ and R ² together form a hydrocarbon ring with the carbon atom to which they are bonded, and the dotted and solid lines are The parallel part represents a single bond or a double bond, X ^{1 to} X ⁸ each represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydrocarbon group or a sulfonyl group, and Y ¹ and Y ² each represent Represents a hydrogen atom, a nitro group, a cyano group or a hydrocarbon group.)

The present invention provides a method for producing cycloalkanol and / or cycloalkanone by oxidizing cycloalkane with molecular oxygen in the presence of a compound represented by the formula:

  According to the present invention, cycloalkanol and / or cycloalkanone can be produced with high selectivity by oxidizing cycloalkane with a good conversion rate.

  Hereinafter, the present invention will be described in detail. In the present invention, cycloalkane is used as a raw material, which is oxidized with molecular oxygen in the presence of a catalyst to produce the corresponding cycloalkanol and / or cycloalkanone.

  Examples of the raw material cycloalkane include, for example, cycloalkane having no substituent on the ring, such as cyclopropane, cyclobutane, cyclopentane, cyclohexane, cycloheptane, cyclooctane, cyclodecane, and cyclooctadecane. Examples include polycyclic cycloalkanes such as norbornane, decalin, and adamantane, and cycloalkanes having a substituent on the ring such as methylcyclopentane and methylcyclohexane. The number of carbon atoms is usually about 3 to 20. . Two or more kinds of cycloalkanes can be used as necessary.

  An oxygen-containing gas is usually used as the molecular oxygen source. This oxygen-containing gas may be, for example, air, pure oxygen, or air or pure oxygen diluted with an inert gas such as nitrogen, argon, or helium. Good. Further, oxygen-enriched air obtained by adding pure oxygen to air can also be used.

  In the present invention, a compound represented by the above formula (1) [hereinafter sometimes referred to as compound (1)] is used as a catalyst for oxidizing cycloalkane with molecular oxygen. By using a cobalt complex having such a predetermined salen as a ligand as a catalyst, cycloalkane and / or cycloalkanone can be produced with high selectivity by allowing oxidation of cycloalkane to proceed smoothly. .

In the formula (1), when R ¹ and R ² are each a hydrocarbon group, the hydrocarbon group may be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group. .

  Here, the aliphatic hydrocarbon group is a residue obtained by removing hydrogen from an aliphatic hydrocarbon, and its carbon number is usually about 1 to 20. Specific examples thereof include alkyl groups such as methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, s-butyl group and t-butyl group; vinyl group, allyl group and methallyl group. And alkynyl groups such as ethynyl groups and propargyl groups.

  An alicyclic hydrocarbon group is a residue obtained by removing hydrogen from an alicyclic hydrocarbon, and its carbon number is usually about 3 to 20. The alicyclic hydrocarbon group may be a residue obtained by removing hydrogen from the aliphatic ring of the alicyclic hydrocarbon, or remove hydrogen from the aliphatic chain of the alicyclic hydrocarbon having an aliphatic chain. It may be a residue. Specific examples thereof include a cycloalkyl group such as a cyclopropyl group, a cyclobutyl group, a cyclopentyl group and a cyclohexyl group; a cycloalkylalkyl group such as a cyclopentylmethyl group and a cyclohexylmethyl group.

  The aromatic hydrocarbon group is a residue obtained by removing hydrogen from an aromatic hydrocarbon, and its carbon number is usually about 6 to 20. The aromatic hydrocarbon group may be a residue obtained by removing hydrogen from an aromatic ring of an aromatic hydrocarbon, or a residue obtained by removing hydrogen from the aliphatic chain of an aromatic hydrocarbon containing an aliphatic chain. It may be a group, or may be a residue obtained by removing hydrogen from an aliphatic ring of an aromatic hydrocarbon containing an aliphatic ring. Specific examples thereof include aryl groups such as phenyl group, tolyl group and naphthyl group; arylalkyl groups (aralkyl group) such as benzyl group and phenethyl group.

When R ¹ and R ² are combined to form a hydrocarbon ring together with the carbon atom to which they are bonded, this hydrocarbon ring is an alicyclic hydrocarbon ring or an aromatic hydrocarbon ring. be able to. Specific examples of the alicyclic hydrocarbon ring include cycloalkane rings such as cyclopentane ring, cyclohexane ring and cyclooctane ring; cycloalkene rings such as cyclopentene ring, cyclohexene ring and cyclooctene ring. The carbon number is usually about 5-20. Specific examples of the aromatic hydrocarbon ring include a benzene ring, a naphthalene ring, an anthracene ring, a phenanthrene ring, and the like, and the number of carbon atoms is usually about 6 to 20. Furthermore, these hydrocarbon rings may have a hydrocarbon group on the ring. And this hydrocarbon group can also be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group like the hydrocarbon group which represents R < ¹ > and R < ² >, for example, The same as the examples of the hydrocarbon group representing R ¹ and R ² .

In the formula (1), when at least one of X ^{1 to} X ⁸ is a hydrocarbon group, this hydrocarbon group is also an aliphatic hydrocarbon group, an aliphatic group, like the hydrocarbon group representing R ¹ and R ^2. It can be a cyclic hydrocarbon group or an aromatic hydrocarbon group. And the example is the same as the example of the hydrocarbon group showing R < ¹ > and R < ² >.

In addition, when at least one of X ^{1 to} X ⁸ is a sulfonyl group, the sulfonyl group can be a hydrocarbon group bonded to an unsubstituted sulfonyl group (—SO ₂ —). And this hydrocarbon group can also be an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, or an aromatic hydrocarbon group like the hydrocarbon group which represents R < ¹ > and R < ² >, for example, The same as the examples of the hydrocarbon group representing R ¹ and R ² .

In the formula (1), when at least one of Y ¹ and Y ² is a hydrocarbon group, this hydrocarbon group is an aliphatic hydrocarbon group, an aliphatic group, as well as the hydrocarbon group representing R ¹ and R ^2. It can be a cyclic hydrocarbon group or an aromatic hydrocarbon group. And the example is the same as the example of the hydrocarbon group showing R < ¹ > and R < ² >.

In the formula (1), R ¹ and R ² are preferably combined together to form a hydrocarbon ring together with the carbon atom to which they are bonded. Moreover, it is preferable that at least one of X ^{1 to} X ⁸ is a nitro group or a hydrocarbon group, and the other is preferably a hydrogen atom. Y ¹ and Y ² are each preferably a hydrogen atom or a hydrocarbon group.

  Compound (1) is a known method such as the method described in Journal of Organic Chemistry, Vol. 56, page 2296 (published in 1991), Applied Catalysis A: General ( Applied Catalysis A: General), 273, 193 (issued in 2004).

  The oxidation reaction can be carried out by bringing cycloalkane into contact with molecular oxygen in the presence of compound (1). The usage-amount of a compound (1) is 0.01-100 weight ppm normally with respect to cycloalkane, Preferably it is 0.1-50 weight ppm. The oxidation reaction is preferably performed as a homogeneous liquid phase reaction in a state where the compound (1) is dissolved in the reaction mixture.

  It is also effective to use a cocatalyst for further improving the conversion rate of cycloalkane and the selectivity of cycloalkanol and / or cycloalkanone. The type is appropriately selected, but it is advantageous to use a cobalt salt of a carboxylic acid. The cobalt salt of the carboxylic acid can be a monovalent or polyvalent aliphatic carboxylic acid, a cycloaliphatic carboxylic acid or a cobalt salt of an aromatic carboxylic acid, and suitable examples thereof include cobalt acetate, 2-ethyl Examples include cobalt hexanoate, cobalt naphthenate, cobalt oxalate, cobalt laurate, cobalt palmitate, and cobalt stearate. The amount of cobalt carboxylate used is usually 0.01 to 100 ppm by weight, preferably 0.1 to 50 ppm by weight, based on cycloalkane.

  The reaction temperature is usually 0 to 200 ° C., preferably 100 to 180 ° C., and the reaction pressure is usually 0.01 to 10 MPa, preferably 0.1 to 2 MPa. As the reaction solvent, for example, a nitrile solvent such as acetonitrile or benzonitrile, a carboxylic acid solvent such as acetic acid or propionic acid, or the like can be used.

  The post-treatment operation after the oxidation reaction is not particularly limited, and examples thereof include a method in which the reaction mixture is washed with water to separate the compound (1) and then distilled. When the reaction mixture contains a cycloalkyl hydroperoxide corresponding to the starting cycloalkane, it can be converted to the desired cycloalkanol or cycloalkanone by alkali treatment, reduction treatment or the like.

  Examples of the present invention will be described below, but the present invention is not limited thereto. The analysis of cyclohexane, cyclohexanone, cyclohexanol and cyclohexyl hydroperoxide in the reaction solution was performed by gas chromatography. From this result, the conversion rate of cyclohexane and the selectivity of cyclohexanone, cyclohexanol and cyclohexyl hydroperoxide were calculated. .

Example 1
Cobalt (II) N, N′-bis (3,5-di-t-butylsalicylidene) -cis-1,2-cyclohexanediamine (in the above formula (1), R ¹ and R ² together To form a cyclohexane ring together with the carbon atoms to which they are bonded, X ² , X ⁴ , X ⁵ and X ⁷ are t-butyl groups, and X ¹ , X ³ , X ⁶ and X ⁸ are is a hydrogen atom, Y ¹ and Y ² is a hydrogen atom compound] 0.0012g (2.0 × 10 ^-6 mol) and cobalt 2-ethylhexanoate (II) 0.00069g (2.0 × 10 - ⁶ mol) was dissolved in 1666.4 g (19.8 mol) of cyclohexane to prepare a feed solution (catalyst / raw material solution). Into a 1 L autoclave was charged 278 g of the above supply liquid, and the pressure was increased to 0.9 MPa with nitrogen, and then the temperature was increased to 140 ° C. while circulating nitrogen. In this, while supplying air at a flow rate of 275 Nml / min, the feed solution was supplied at 4.6 g / min, and a continuous reaction was performed for 4 hours under the conditions of a reaction temperature of 140 ° C. and a residence time of 1 hour. As a result of analyzing the reaction solution, the conversion of cyclohexane was 4.4%, the selectivity of cyclohexanone was 27.5%, the selectivity of cyclohexanol was 35.1%, and the selectivity of cyclohexyl hydroperoxide was 19.2%. (Total selectivity 81.8%).

Example 2
Cobalt (II) N, N′-bis (2-hydroxybenzophenylidene) -1,2-phenylenediamine as a catalyst [in the above formula (1), R ¹ and R ² are combined together to bond A compound in which a benzene ring is formed together with a carbon atom, X ^{1 to} X ⁸ are hydrogen atoms, and Y ¹ and Y ² are phenyl groups] 0.0010 g (2.0 × 10 ⁻⁶ mol) and 2- The same operation as in Example 1 was performed except that 0.00069 g (2.0 × 10 ⁻⁶ mol) of cobalt (II) ethylhexanoate was used. The conversion of cyclohexane was 4.2%, the selectivity of cyclohexanone was 29.3%, the selectivity of cyclohexanol was 31.7%, and the selectivity of cyclohexyl hydroperoxide was 22.0% (total selection) (Rate 83.0%).

Example 3
Cobalt (II) N, N′-bis (5-nitrosalicylidene) -1,2-cyclohexanediamine as a catalyst [in the above formula (1), R ¹ and R ² are combined to bind to each other. A cyclohexane ring is formed together with a carbon atom, X ² and X ⁷ are nitro groups, X ¹ , X ³ , X ⁴ , X ⁵ , X ⁶ and X ⁸ are hydrogen atoms, Y ¹ and Y ² Is a hydrogen atom (in terms of the stereochemistry of R ¹ and R ² , a mixture of cis and trans isomers) 0.0009 g (2.0 × 10 ⁻⁶ mol) and cobalt 2-ethylhexanoate (II) 0 The same operation as in Example 1 was conducted, except that 0.0690 g (2.0 × 10 ⁻⁶ mol) was used. The conversion of cyclohexane was 4.2%, the selectivity of cyclohexanone was 23.2%, the selectivity of cyclohexanol was 40.4%, and the selectivity of cyclohexyl hydroperoxide was 19.2% (total selection) (82.8% rate).

Example 4
Cobalt (II) N, N′-bis (3-nitrosalicylidene) -1,2-cyclohexanediamine as a catalyst [in the above formula (1), R ¹ and R ² are combined to bind to each other. A cyclohexane ring is formed together with a carbon atom, X ⁴ and X ⁵ are nitro groups, X ¹ , X ² , X ³ , X ⁶ , X ⁷ and X ⁸ are hydrogen atoms, Y ¹ and Y ² Is a hydrogen atom (in terms of the stereochemistry of R ¹ and R ² , a mixture of cis and trans isomers) 0.0009 g (2.0 × 10 ⁻⁶ mol) and cobalt 2-ethylhexanoate (II) 0 The same operation as in Example 1 was conducted, except that 0.0690 g (2.0 × 10 ⁻⁶ mol) was used. The conversion of cyclohexane was 4.2%, the selectivity of cyclohexanone was 25.1%, the selectivity of cyclohexanol was 41.4%, and the selectivity of cyclohexyl hydroperoxide was 18.4% (total selection) Rate 84.9%).

Comparative Example 1
Cobalt (II) N, N′-bis (3,5-di-t-butylsalicylidene) ethylenediamine as a catalyst [in the above formula (1), R ¹ and R ² are hydrogen atoms, X ² , X ⁴ , X ⁵ and X ⁷ are t-butyl groups, X ¹ , X ³ , X ⁶ and X ⁸ are hydrogen atoms, and Y ¹ and Y ² are hydrogen atoms] 0.0011 g (2. 0 × 10 ⁻⁶ mol) and 0.00069 g (2.0 × 10 ⁻⁶ mol) of cobalt (II) 2-ethylhexanoate were used, and the same operation as in Example 1 was performed. The conversion of cyclohexane was 4.2%, the selectivity of cyclohexanone was 25.0%, the selectivity of cyclohexanol was 36.8%, and the selectivity of cyclohexyl hydroperoxide was 16.9% (total selection) (Rate 78.7%).

Comparative Example 2
Cobalt (II) N, N′-bis (2-hydroxybenzophenylidene) ethylenediamine as a catalyst [In the above formula (1), R ¹ and R ² are hydrogen atoms, and X ^{1 to} X ⁸ are hydrogen atoms. , Y ¹ and Y ² is a phenyl group compound] 0.0009g (2.0 × 10 ^-6 mol) and 2-ethylhexanoic acid cobalt (II) 0.00069g (2.0 × 10 -6 mol) The same operation as in Example 1 was performed except that it was used. The conversion of cyclohexane was 4.2%, the selectivity of cyclohexanone was 25.4%, the selectivity of cyclohexanol was 37.5%, and the selectivity of cyclohexyl hydroperoxide was 16.9% (total selection) (Rate 79.8%).

Claims (6)

Following formula (1)

(Wherein R ¹ and R ² each represent a hydrocarbon group, or R ¹ and R ² together form a hydrocarbon ring with the carbon atom to which they are bonded, and the dotted and solid lines are The parallel part represents a single bond or a double bond, X ^{1 to} X ⁸ each represents a hydrogen atom, a halogen atom, a nitro group, a cyano group, a hydrocarbon group or a sulfonyl group, and Y ¹ and Y ² each represent Represents a hydrogen atom, a nitro group, a cyano group or a hydrocarbon group.)
A process for producing cycloalkanol and / or cycloalkanone, characterized in that cycloalkane is oxidized with molecular oxygen in the presence of a compound represented by the formula: The method according to claim 1, wherein in formula (1), R ¹ and R ² are combined to form an alicyclic hydrocarbon ring together with the carbon atom to which they are bonded. The method according to claim 1, wherein in formula (1), R ¹ and R ² are combined to form an aromatic hydrocarbon ring together with the carbon atom to which they are bonded. The method according to any one of claims 1 to 3, wherein in formula (1), at least one of X ^{1 to} X ⁸ is a nitro group or a hydrocarbon group.   Furthermore, the method in any one of Claims 1-4 which oxidize in the presence of the cobalt salt of carboxylic acid. The method according to claim 1, wherein the cycloalkane is cyclohexane.