JPH0725815A - Production of aliphatic dicarboxylic acid - Google Patents

Abstract

PURPOSE:To provide an industrially inexpensive production process for very useful aliphatic dicarboxylic acids such as succinic or glutaric acid by fixing oxygen efficiently. CONSTITUTION:The liquid-phase oxidation of a cycloalkyl-substituted aromatic hydrocarbon of the formula: Ar-(B)n (Ar is an aromatic hydrocarbon group; B is cyclohexyl or cyclopentyl; n is 1 or 2) is effected using molecular oxygen to give an aromatic carboxylic acid and an aliphatic dicarboxylic acid.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing an aliphatic dicarboxylic acid. In particular, it relates to an industrial production method of glutaric acid, which is expected to be in demand as a synthetic polymer raw material or a resin plasticizer raw material, succinic acid used as a food additive such as an acidulant, and a bathing agent.

[0002]

2. Description of the Related Art Glutaric acid (1,3-propanedicarboxylic acid) is a very important substance which is expected to be in demand as a monomer for polyester, and a diester with alcohol as a plasticizer for various resins. In addition, succinic acid (1,2-ethanedicarboxylic acid) is a substance used as a food additive such as an acidulant, a seasoning, or sake brewing, and a bath agent whose demand has been increasing in recent years.

These aliphatic dicarboxylic acids have hitherto been produced by aerial oxidation of the corresponding cycloalkane or cycloalkene or by a reagent oxidation method using nitric acid or a ruthenium-based oxidizing agent. However, these methods are not industrial production methods because of low yields and expensive oxidizers (Japanese Patent Laid-Open No. 50-35109).
U.S. Pat. No. 3,409,649, JP-A-61-28
9056 publication).

A method for synthesizing succinic acid from acrylonitrile or alkali cyanide and water in the presence of a palladium catalyst (Japanese Patent Application Laid-Open No. 50-116414) has also been proposed, but it uses an expensive catalyst. However, there is a problem as an industrial manufacturing method. Further, a process of separating and recovering glutaric acid, which is a by-product when adipic acid is synthesized from cyclohexanone or cyclohexanol, has been proposed (JP-A-52-778818, JP-A-5-78818).
No. 2-778819), the recovery rate is not always satisfactory. Therefore, succinic acid and the like are industrially produced by an extremely inefficient method of hydrolyzing maleic anhydride and further hydrogenating with a nickel catalyst. On the other hand, a method for producing an aromatic carboxylic acid by an oxidation reaction of an alkyl aromatic hydrocarbon is known, but in the oxidation reaction of an aromatic hydrocarbon having a long-chain alkyl substituent, the carbon atom of the alkyl substituent is In many cases, hydrogen atoms are converted to CO ₂ and hydrogen atoms are consumed as water, and oxygen is not efficiently used.

[0005]

Therefore, an object of the present invention is to efficiently introduce oxygen by using a cycloalkyl aromatic hydrocarbon as a raw material so that the combustion reaction with the aromatic carboxylic acid is substantially minimized. Another object of the present invention is to provide a method for producing an aliphatic dicarboxylic acid that is small in size and industrially advantageous. As a result of intensive studies on the oxidation reaction of various aromatic hydrocarbons, the present inventors have surprisingly found that when a specific cycloalkyl aromatic hydrocarbon is oxygen-oxidized in a liquid phase, the introduced oxygen is more efficient. It was found that an aliphatic dicarboxylic acid can be obtained together with the corresponding aromatic carboxylic acid. The present invention is based on these findings.

[0006]

Accordingly, the present invention provides a compound represented by the general formula (I):

Embedded image Ar- (B) n (I) (wherein Ar is an aromatic hydrocarbon group, B is a cyclohexyl group or a cyclopentyl group, and n is 1 or 2) The present invention relates to a method for producing an aliphatic dicarboxylic acid, which comprises subjecting a cycloalkyl-substituted aromatic hydrocarbon to oxygen oxidation in a liquid phase to produce an aliphatic dicarboxylic acid together with an aromatic carboxylic acid.

In the above general formula (I), Ar is a monovalent or divalent aromatic hydrocarbon group having 6 to 14 carbon atoms, preferably 6 to 12 carbon atoms, and examples thereof include a phenyl group and a phenylene group. Group, biphenyl group, biphenylene group, naphthyl group, naphthylene group, indenyl group, acenaphthyl group, acenaphthylene group and the like. The aromatic hydrocarbon group Ar preferably has no substituent other than the substituent B. When the aromatic hydrocarbon group Ar is a divalent group,
Each substituent B is different or preferably the same, and the position of each substituent may be arbitrary.

Examples of the cycloalkyl-substituted aromatic hydrocarbon represented by the general formula (I) include cyclohexylbenzene, 1,4-dicyclohexylbenzene, cyclopentylbenzene, p-cyclohexylbiphenyl, p,
p'-dicyclohexylbiphenyl, 2-cyclohexylnaphthalene, 2,6-dicyclohexylnaphthalene,
2,6-dicyclopentylnaphthalene or 4,7-dicyclohexylacenaphthylene can be used.

Specifically, the raw material to be used can be selected depending on the kind of the target aliphatic carboxylic acid and the kind of the aromatic carboxylic acid. For example, when the substituent B is a cyclohexyl group, glutaric acid is mainly formed as an aliphatic carboxylic acid, and when the substituent B is a cyclopentyl group, succinic acid is mainly formed as an aliphatic carboxylic acid. To be done. Further, when the number of the substituents B is 1, an aromatic monocarboxylic acid corresponding to the aromatic group Ar is obtained, and when the number of the substituents B is 2, an aromatic dicarboxylic acid corresponding to the aromatic group Ar is obtained. can get. Therefore, cyclohexylbenzene may be used when synthesizing glutaric acid and benzoic acid, and 2-cyclopentylnaphthalene may be used as a raw material when succinic acid and 2-naphthoic acid are synthesized. Further, these cycloalkyl aromatic hydrocarbons are easily obtained by alkylating the corresponding aromatic hydrocarbon with an alkylating agent such as a halogenated cycloalkane, cycloalkene, or cycloalkenyl alcohol under a Friedel-Crafts catalyst. be able to.

In the method of the present invention, a cycloalkyl aromatic hydrocarbon is dissolved in an organic solvent such as a fatty acid, particularly a lower fatty acid having 2 to 4 carbon atoms (eg acetic acid, propionic acid, butyric acid or isobutyric acid). 1 to 150 kg /
Oxidation in the presence of cm ² of oxygen gas opens the cycloalkane to allow synthesis of the corresponding aliphatic dicarboxylic acid. The oxygen gas used may be not only pure oxygen gas but also air or a mixed gas of oxygen and an inert gas (for example, nitrogen gas).

The method of the present invention is preferably carried out in the presence of a specific oxidation catalyst. These oxidation catalysts can include cobalt compounds, manganese compounds, cerium compounds, and copper compounds, as well as mixtures thereof. The compound may be a halide (for example, chloride,
Bromides or iodides) or the metal salts of lower aliphatic carboxylic acids having 2 to 4 carbon atoms (for example, acetic acid, propionic acid, butyric acid or isoacetic acid) can be used. The amount of this catalyst used may be appropriately selected depending on the optimum yield, but is usually 0.001 molar equivalent or more, preferably 0.005 to 0.005 molar equivalents relative to the cycloalkyl aromatic hydrocarbon.
It is 1.0 molar equivalent.

In the method of the present invention, a bromine compound such as an alkali metal bromine compound (eg, sodium bromide or potassium bromide), a salt of ammonium bromide, etc., as a cocatalyst, and bromoacetic acid or dibromoethane, etc. It is preferable to use the brominated organic compound of. The amount of the co-catalyst used may be appropriately selected according to the optimum yield, but is usually 0.
It is 001 molar equivalent or more, preferably 0.005 to 1.0 molar equivalent.

In the method of the present invention, the reaction conditions are not particularly limited, but are atmospheric pressure or 100 kg / cm ³ G
0.1 to 1 at a temperature of 50 to 250 ° C. under the following pressure.
A reaction time of 0 hours is preferably used. In particular, in order to prevent the sequential oxidation of the aliphatic carboxylic acid formed as a product and to promote the ring opening of the cycloalkane by the oxidation reaction, pressurization of 50 kg / cm ³ G or less, 1
It is preferably carried out in the temperature range of 00 to 200 ° C.

[0014]

The present invention will be described in detail below with reference to examples, but these do not limit the scope of the present invention. Examples 1 to 10 An autoclave having an internal volume of 200 ml was charged with 4.8 g of cyclohexylbenzene, various metal salts described in Table 1 below, various bromine compounds, and a solvent (40 ml), and the oxygen pressure up to 30 kg / cm ³ G. Boosted. The temperature was raised to 120 ° C. and kept for 2 hours. After cooling the autoclave, the gas was released and the contents were taken out. A part of the content was collected, esterified with methanol using sulfuric acid as a catalyst in benzene, and the acid component was quantified by gas chromatography. The results are shown in Table 1. All yields are based on cyclohexylbenzene charged.

[0015]

[Table 1]

[0016] Similarly to Example 11 Example 1, the internal volume autoclave 1,4-dicyclohexyl benzene 7.3g of 200 ml, cobalt acetate _{[Co (OAc) 2 · 4H 2} O ] 0.4 g, manganese acetate [Mn (OAc) ₂ · 4H ₂ O] 0.4 g, cerium acetate _{[Ce (OAc) 3 · 4H 2} O ] 0.4 g,
Sodium bromide [NaBr] 0.66 g and acetic acid 40
The oxygen pressure was raised to 30 kg / cm ³ G. It heated up to 120 degreeC and hold | maintained for 5 hours. The product was esterified with methanol and the acid component was quantified by gas chromatography. As a result, succinic acid was 20% and glutaric acid was 75% based on 1,4-dicyclohexylbenzene.
It was obtained with a yield of. In addition, terephthalic acid was simultaneously obtained in a yield of 95%.

Example 12 As in Example 1, in an autoclave having an internal volume of 200 ml, 4.4 g of cyclopentylbenzene and cobalt acetate [C
_{o (OAc) 2 · 4H 2} O ] 0.4 g, manganese acetate _{[Mn (OAc) 2 · 4H 2} O ] 0.4 g, sodium bromide 0.66 g, and g of acetic acid 40 ml, oxygen pressure 30kg / cm ³ The pressure was raised to G. The temperature was raised to 120 ° C. and kept for 2 hours. The product was esterified with methanol and the acid component was quantified by gas chromatography. As a result, succinic acid was obtained in a yield of 40%. In addition, benzoic acid was simultaneously obtained in a yield of 98%.

[0018] Similarly to Example 13 Example 1, the autoclave 200 ml 2-cyclohexyl naphthalene 6.3 g, cobalt acetate _{[Co (OAc) 2 · 4H 2} O ] 0.4 g, copper acetate [Cu (OAc ) ₂ · 4H ₂ O] 0.05 g, manganese acetate _{[Mn (OAc) 2 · 4H 2} O ] 0.4 g, sodium bromide 0.66 g, and g of acetic acid 40 ml, boosted until the oxygen pressure 30kg / cm ³ G did. The temperature was raised to 120 ° C. and kept for 2 hours. The product was esterified with methanol and the acid component was quantified by gas chromatography. As a result, glutaric acid was obtained in a yield of 36% and succinic acid was obtained in a yield of 15%. In addition, 2-naphthoic acid was simultaneously obtained in a yield of 95%.

Example 14 Using 8.8 g of p, p'-dicyclohexylbiphenyl as a substrate, oxidation was carried out under the same conditions as in Example 2, and the product was methyl-esterified and analyzed. As a result, p, p'- 35% succinic acid and 80% glutaric acid were obtained based on dicyclohexylbiphenyl. At the same time, p, p '
-Biphenyldicarboxylic acid was obtained in a yield of 80%.

[0020]

INDUSTRIAL APPLICABILITY According to the present invention, a specific cycloalkyl aromatic hydrocarbon is oxygen-oxidized to efficiently fix oxygen and simultaneously produce a corresponding aliphatic dicarboxylic acid and aromatic carboxylic acid. Thus, carboxylic acids such as succinic acid and glutaric acid, which are extremely useful substances, can be industrially produced at low cost.

Continuation of the front page (51) Int.Cl. ⁶ Identification number Internal reference number in the agency FI Technical display location C07C 63/06 // C07B 61/00 300 (72) Inventor Junkan Yamamoto 3-34-Honamanuma, Suginami-ku, Tokyo 38-107

Claims (3)

[Claims] 1. A compound represented by the general formula (I): Ar- (B) n (I) (wherein Ar is an aromatic hydrocarbon group, B is a cyclohexyl group or a cyclopentyl group, and n Is 1 or 2) to produce an aliphatic dicarboxylic acid together with an aromatic carboxylic acid by oxygen-oxidizing a cycloalkyl-substituted aromatic hydrocarbon in a liquid phase. . 2. The production method according to claim 1, which is carried out in the presence of at least one oxidation catalyst selected from the group consisting of cobalt compounds, manganese compounds, cerium compounds and copper compounds. 3. The production method according to claim 2, which is carried out in the presence of a bromine compound.