JP2001253845A - Method for producing adipic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a producing method for obtaining dibasic acids simultaneously comprising glutaric acid and succinic acid in addition to adipic acid as a principal reaction product with high selectivity by oxidizing cyclohexanone with molecular oxygen in an aqueous solvent. SOLUTION: Cyclohexanone is oxidized with molecular oxygen in an aqueous solvent in the presence of both of an iron compound and a vanadium compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing adipic acid by oxidizing cyclohexanone with molecular oxygen.

[0002]

2. Description of the Related Art In order to produce adipic acid by oxidizing cyclohexanone with molecular oxygen, a method of oxidizing cyclohexanone in a solvent mainly containing acetic acid using a manganese compound or the like as a catalyst is described, for example, in French Patent No. 2,541,993. And other reports. In the method of producing adipic acid by oxidizing with molecular oxygen using an acetic acid solvent, there is a concern that the material of the reactor may be corroded and acetic acid may remain as a trace impurity in adipic acid. On the other hand, when an aqueous solvent is used, there is an advantage that adipic acid having few impurities can be directly precipitated from the reaction solution and purified.

A technique for producing adipaldehyde acid (also known as 5-formylvaleric acid) by oxidizing cyclohexanone with molecular oxygen in the presence of water, an iron compound and a third component is disclosed, for example, in Japanese Patent Application Laid-Open No. 58-1983. 172342, JP-A-58-
203936, JP-A-59-16851,
It is disclosed in JP-A-59-42341. According to these, it is described that adipoaldehyde acid can be obtained with high selectivity, but there is no description about adipic acid, which is an object of the present invention.

[0004] Also, it has been reported that adipic acid can be obtained using an aqueous solvent, for example, as described in J. Am. Org. Chem. , Vol.
58, No. 21, 1993, pages 5663 to 5665
Page. However, H ₅ [PMo ₁₀ V ₂
This system catalyzed by [O ₄₀ ] .30H ₂ O has a low adipic acid yield of 18%.

[0005]

SUMMARY OF THE INVENTION The present invention oxidizes cyclohexanone with molecular oxygen in an aqueous solvent to produce a dibasic acid composed mainly of adipic acid and glutaric acid and succinic acid with high selectivity. The purpose is to provide a way to gain.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, cyclohexanone has been used in the presence of an iron compound and a vanadium compound by using molecular oxygen in an aqueous solvent. The present inventors have found that when the oxidation reaction is carried out, dibasic acids including adipic acid as a main component, including glutaric acid and succinic acid, can be obtained with high selectivity, and the present invention has been accomplished.

That is, the present invention provides cyclohexanone,
This is a method for producing adipic acid, wherein an oxidation reaction is performed using molecular oxygen in an aqueous solvent in the presence of an iron compound and a vanadium compound. The iron compound of the present invention is preferably a compound soluble in water, for example, ferrous chloride, ferric chloride, ferrous bromide, ferric bromide, ferrous iodide, and ferric nitrate. Ferrous, ferric nitrate, ferrous sulfate, inorganic iron salts such as ferric sulfate, and the like, more preferably from the viewpoint of selectivity of adipic acid and suppression of chlorinated cyclohexanone derivatives, It is Hitotetsu. These iron compounds may be used alone or as a mixture.

The amount of the iron compound used in the present invention is preferably 1 to 100 mol%, more preferably 5 to 50 mol%, as iron with respect to cyclohexanone from the viewpoints of suppressing side reactions and separating after the reaction. is there. Examples of the vanadium compound of the present invention include vanadium oxide sulfate, bis (acetylacetonato) oxovanadium,
Examples include vanadium pentoxide, vanadium sulfate, ammonium metavanadate, vanadium chloride, vanadium iodide, and vanadium acetate, and preferably vanadium oxide sulfate, which is soluble in water. These vanadium compounds may be used alone or as a mixture.

The amount of the vanadium compound of the present invention is preferably 1 to 1 as vanadium relative to cyclohexanone.
It is 100 mol%, more preferably 5 to 50 mol%.
The solvent of the present invention is mainly composed of water, but can be mixed as long as it is a component that is soluble in water.
Carboxylic acids such as acetic acid, propionic acid, butyric acid and valeric acid; nitriles such as acetonitrile, propionitrile and benzonitrile; aromatic hydrocarbons such as benzene and toluene; esters such as ethyl acetate, butyl acetate and ethyl propionate Ketones such as methyl ethyl ketone, diethyl ketone and methyl isobutyl ketone; aldehydes such as acetaldehyde, propioaldehyde and butyraldehyde; and mixtures thereof. Further, as a reaction accelerator, for example, halogenated compounds such as hydrogen chloride and sodium bromide; and imides such as N-hydroxyphthalimide can be added.

In the practice of the present invention, it is preferable to add sulfonic acids to improve the reaction rate and the like.
Examples of the sulfonic acids include methanesulfonic acid, benzenesulfonic acid, benzenedisulfonic acid, paratoluenesulfonic acid, metaxylenesulfonic acid, paraxylenesulfonic acid, metanitrobenzenesulfonic acid, paranitrobenzenesulfonic acid, naphthalenesulfonic acid, and naphthalenedisulfonic acid. Acid and trifluoromethanesulfonic acid. These sulfonic acids may be used alone or as a mixture.

The amount of the sulfonic acids used is, for example, 0.1 to 100 mol%, more preferably 1 to 50 mol%, based on cyclohexanone. The cyclohexanone of the present invention is
Cyclohexanol which is obtained simultaneously with the production of cyclohexanone or used as a starting material may be present to some extent. The molecular oxygen of the present invention is
Pure oxygen or nitrogen, helium, argon,
It may be diluted with carbon dioxide or the like, and the oxygen concentration in the supply gas can be selected within a range of 1 to 100%. As the oxygen-containing gas, it is preferable to use oxygen at a low concentration from the viewpoint of safety, and examples thereof include air and an inert gas containing 7% by volume of oxygen.

The amount of the molecular oxygen used in the present invention is usually 0.1 mol or more per 1 mol of cyclohexanone per hour so that the reaction can proceed sufficiently. Immediately after the start of the reaction and / or when the reaction temperature is high, it is preferable to supply an excess of molecular oxygen to cyclohexanone. The reaction temperature for carrying out the reaction can be varied over a wide range, for example, from room temperature to 100
° C, and from the viewpoint of reaction rate and suppression of side reactions,
80 ° C. is preferred. At the start of the reaction, it is important to suppress the temperature rise because of the large amount of heat generated.

The reaction pressure at the time of carrying out the present invention can proceed at normal pressure, but can be pressurized. Examples of the reactor for carrying out the present invention include a bubble column, a stirring tank, and a packed column. When the volume of the reactor to be carried out is small, the coalescence of bubbles becomes predominant, so it is necessary to devise a means for miniaturizing the gas phase.For example, in a stirring tank, high-speed rotation of stirring blades or installation of baffle plates It is preferred to increase the stirring.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described more specifically with reference to Examples and the like, but the present invention is not limited to these Examples and the like.

[0015]

Example 1 A four-necked flask equipped with an oxygen-containing gas blowing tube, a condenser, a stirrer, and a thermometer was charged with 60 mmol of cyclohexanone, 6 mmol of ferrous chloride, 6 mmol of vanadium oxide sulfate, and 3.3 mol of water. Was charged. Then, the mixture was vigorously stirred at 70 ° C. for 3 hours while blowing oxygen gas into the reaction solution at 4 L / hour. When the product in the reaction solution was analyzed by high performance liquid chromatography, the conversion of cyclohexanone was 85%,
The selectivity for adipic acid was 51%, and the selectivity for adipoaldehyde acid was 6%. The conditions for high performance liquid chromatography are as follows.

Mobile phase: A liquid prepared by mixing water and acetonitrile at a volume ratio of 9: 1 and adding phosphoric acid to a concentration of 13 mmol / L Stationary phase: Packed with octadecyl group-bonded silica gel (ODS) Column detector; differential refractometer detector and / or ultraviolet absorbance detector

[0017]

Example 2 In the same manner as in Example 1, the results of a reaction using ferric chloride and vanadium oxide sulfate are shown in Table 1.
Shown in

[0018]

Example 3 In the same manner as in Example 1, the results of the reaction using ferric nitrate and vanadium oxide sulfate are shown in Table 1.
Shown in

[0019]

Example 4 In the same manner as in Example 1, 6 mmol of p-toluenesulfonic acid was added and the reaction was carried out.
Shown in

[0020]

Comparative Example 1 Table 1 shows the results of a reaction performed in the same manner as in Example 1 using a reaction solution containing 60 mmol of cyclohexanone, 6 mmol of ferric chloride, and 3.3 mol of water.

[0021]

Comparative Example 2 Table 1 shows the results of a reaction performed in the same manner as in Comparative Example 1, except that ferrous chloride was replaced with ferric chloride.

[0022]

Comparative Example 3 Table 1 shows the results of a reaction performed in the same manner as in Example 1 using a reaction solution containing 60 mmol of cyclohexanone, 6 mmol of vanadium oxide sulfate, and 3.3 mol of water.

[0023]

Comparative Example 4 In the same manner as in Comparative Example 1, 6 mmol of p-toluenesulfonic acid was added and the reaction was performed.
Shown in As is clear from Table 1, it is understood that adipic acid and dibasic acids can be obtained in a high yield by reacting in the presence of an iron compound and a vanadium compound.

[0024]

[Table 1]

[0025]

According to the present invention, adipic acid can be obtained with high selectivity from cyclohexanone in a water solvent by molecular oxygen, and useful glutaric acid and succinic acid can also be obtained.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (reference) // C07B 61/00 300 C07B 61/00 300 F term (reference) 4H006 AA02 AC46 BA02 BA12 BA19 BA30 BA32 BA36 BA37 BA45 BA50 BA52 BB12 BB16 BB17 BB21 BB31 BB47 BB61 BC31 BC34 BE30 BS10 4H039 CA65 CC50 CH70

Claims (2)

[Claims] 1. A process for producing adipic acid, comprising oxidizing cyclohexanone in the presence of an iron compound and a vanadium compound in an aqueous solvent using molecular oxygen. 2. The method for producing adipic acid according to claim 1, wherein the oxidation reaction is performed in the presence of sulfonic acids.