JP2002249460A - Method for producing 2-butyloctanedioic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing high purity 2-butyloctanedioic acid (especially containing essentially no 1,10-dodecanedioic acid). SOLUTION: The method for producing 2-butyloctanedioic acid is characterized by (1) esterifying 7-cyanoundecanoic acid and/or 2-butyl-7-cyanoheptanoic acid, (2) separating by distillation an ester of 7-cyanoundecanoic acid and/or an ester of 2-butyl-7-cyanoheptanoic acid from the esterified solution, (3) forming a salt of 2-butyl octanedioic acid by hydrolyzing the ester in the presence of an alkaline compound and (4) forming 2-butyloctanedioic acid by treating the hydrolyzed solution with an acid.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for producing 2-butyloctanediacid. More specifically, 7-cyanoundecanoic acid containing 11-cyanoundecanoic acid and / or
Or from 2-butyl-7-cyanoheptanoic acid, a highly pure (substantially free of 1,10-dodecandioic acid) 2-
The present invention relates to a method for producing butyloctane diacid.

[0002] 2-butyloctane diacid is used as an effective electrolyte component in electrolytic capacitors (particularly capacitors having excellent withstand voltage characteristics). Also, polyamide,
It is useful as a raw material for polymers such as polyester and as a curing agent for epoxy resins.

[0003]

2. Description of the Related Art As a method for producing 2-butyloctanediacid, for example, cyclohexane is oxidized and decomposed to form 1,10-
A method is known in which dodecane diacid and 2-butyloctane diacid are formed, and 2-butyloctane diacid is separated from this mixture (Japanese Patent Application Laid-Open Nos. 49-115992 and 50-37716). ).

However, this method is a method for producing 1,10-dodecandioic acid as a main product, so that the amount of 2-butyloctanedioic acid produced is 1% of 1,10-dodecandioic acid.
If it is 0% or less, there is a problem that the yield of 2-butyloctanediacid is low. Also, because separation of 1,10-dodecane diacid and 2-butyloctane diacid is not easy,
There was also a problem that it was difficult to produce high-purity (substantially free of 1,10-dodecanedioic acid) 2-butyloctanedioic acid.

For this reason, 7-cyanoundecanoic acid and / or
Alternatively, 2-butyl-7-cyanoheptanoic acid is hydrolyzed in the presence of an alkaline compound, and then subjected to an acid treatment at a pH of 8.5 or less to remove a precipitated salt by filtration or the like. The acid is extracted with an organic solvent and the organic solvent is removed by evaporation or the like, or water is removed from the filtrate by distillation or evaporation to obtain a high-purity (1,10-dodecanediacid having a low content). ) A method for producing 2-butyloctanediacid with good yield has been proposed (JP-A-2000-38367).

However, in this method, although the yield is improved, the obtained 2-butyloctanediacid has a purity of 9%.
About 1 to 95% by weight (1,10-dodecanediacid is
7% by weight), which was not satisfactory in terms of purity.

[0007]

SUMMARY OF THE INVENTION The present invention is directed to a method for producing 2-butyloctanediacid by solving the above-mentioned problems of the prior art, that is, a method for producing high-purity (particularly, 1,1
It is an object of the present invention to provide a method capable of producing 2-butyloctanediacid (which does not substantially contain 0-dodecanediacid).

[0008]

The object of the present invention is to provide (1)
7-cyanoundecanoic acid and / or 2-butyl-7-cyanoheptanoic acid is esterified, and (2) esterification of 7-cyanoundecanoic acid and / or 2-butyl-7-cyanoheptanoic acid from the esterification reaction solution. The ester is separated by distillation, (3) the ester is hydrolyzed in the presence of an alkaline compound to form a salt of 2-butyloctanediacid, and (4) the hydrolysis reaction solution is treated with an acid to give 2-butyloctane. The problem is solved by a method for producing 2-butyloctane diacid, which comprises producing diacid.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (1) First Step In the present invention, first, 7-cyanoundecanoic acid and / or 2-butyl-7-cyanoheptanoic acid is esterified (reacted with an alcohol) to give A step of producing an ester of cyanoundecanoic acid and / or an ester of 2-butyl-7-cyanoheptanoic acid is performed.

The starting materials 7-cyanoundecanoic acid and 2-butyl-7-cyanoheptanoic acid used are those produced by known methods. Each of these can be used alone, but usually those containing both are used. For example, when producing 11-cyanoundecanoic acid from cyclohexane, the mother liquor (ammonium 7-cyanoundecanoate and ammonium 2-butyl-7-cyanoheptanoate after purification of ammonium 11-cyanoundecanoate by crystallization). 7-cyanoundecanoic acid and 2-butyl-7-cyanoheptanoic acid (JP-A-63
145261) is preferably used. In this case, 7-cyanoundecanoic acid and 2-butyl-7-
The ratio of cyanoheptanoic acid is not particularly limited.

The raw materials derived from the production of 11-cyanoundecanoic acid include 7-cyanoundecanoic acid and 2-butyl-7-cyanoheptanoic acid.
Various compounds produced as by-products during the production of -cyanoundecanoic acid or 11-cyanoundecanoic acid may be contained.

The alcohol used in the esterification includes an aliphatic alcohol having 1 to 6 carbon atoms. Among them, aliphatic alcohols having 2 to 3 carbon atoms are preferable, and among them, 2-propanol is particularly preferable. The amount of alcohol used is 7-cyanoundecanoic acid and 2-butyl-
1 to 20 times mol based on the total of 7-cyanoheptanoic acid,
Further, it is preferably 1.5 to 16 times mol, particularly preferably 2 to 12 times mol.

In the esterification, it is preferable to use an acid catalyst. Examples of the acid catalyst include inorganic acids such as hydrochloric acid, sulfuric acid, and phosphoric acid, formic acid, acetic acid, oxalic acid, benzenesulfonic acid,
Organic acids such as p-toluenesulfonic acid are preferred. Of these, inorganic acids are preferred, and sulfuric acid is particularly preferred. The amount of the acid catalyst used is 0.01 to 2 times mol, more preferably 0.05 to 1.6 times mol, based on the total of 7-cyanoundecanoic acid and 2-butyl-7-cyanoheptanoic acid,
In particular, it is preferably 0.1 to 1.2 times mol. The acid catalyst may be used after being diluted with water, but it is generally preferable to use the acid catalyst without dilution.

The esterification temperature is preferably from 40 to 180 ° C, more preferably from 60 to 160 ° C, particularly preferably from 80 to 140 ° C. The pressure is not particularly limited. The reaction atmosphere is not particularly limited, and may be air or an inert gas atmosphere such as nitrogen. The time required for the esterification varies depending on the reaction conditions such as the temperature and the reaction amount, but is usually 1 to 20 hours. In addition, it is preferable that the water generated at the time of esterification is extracted out of the reaction system.

After completion of the esterification, the process may proceed to the next step, but it is usually preferable to proceed to the next step after neutralizing the acid catalyst. The neutralization treatment is performed by adding an alkali compound to the esterification reaction solution, and the temperature at that time is preferably 0 to 50 ° C, more preferably 10 to 40 ° C, and the amount of the alkali compound used is an acid catalyst. 0.1 to 5 equivalents, more preferably 0.2 to 2 equivalents, and especially 0.5 to 1 equivalent
Preferably, it is 1.5 equivalents. The alkali compound may be added as an aqueous solution or may be added as it is.

Examples of the alkali compound include inorganic alkali compounds such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate, and ammonia; and organic alkali compounds such as triethylamine. Is mentioned. Among them, inorganic alkali compounds are preferable, and among them, sodium hydroxide, potassium hydroxide, sodium carbonate, and potassium carbonate are more preferable, and sodium carbonate is particularly preferable.

The esterification in the first step can be carried out in a continuous manner or in a batch manner using a conventional reactor equipped with a stirrer. In particular, a reactor equipped with a reflux device is preferably used because loss due to evaporation of alcohol can be suppressed. The reaction apparatus used in this step can be used in the third step and the fourth step.

(2) Second Step In the present invention, the ester of 7-cyanoundecanoic acid and / or 2 is obtained from the esterification reaction solution obtained in the first step.
A step of distilling off the ester of -butyl-7-cyanoheptanoic acid is performed.

This distillation separation can be carried out using a simple distillation apparatus, but a precision distillation apparatus (packed tower type distillation apparatus,
It is preferably performed using an Oldershaw-type distillation apparatus. The number of theoretical plates in precision distillation is 5 or more (for example,
5-200), and the reflux ratio is 1 or more (for example, 1-10
0). In the distillation separation, the atmosphere is not particularly limited. The distillation temperature and the pressure differ depending on the alcohol used for the esterification. For example, when distilling and separating 2-propyl ester of 7-cyanoundecanoic acid or 2-propyl ester of 2-butyl-7-cyanoheptanoic acid, the pressure may vary. Is preferably 0.01 torr to normal pressure and the distillation column top temperature is preferably 80 to 300 ° C, more preferably the pressure is 0.01 to 400 torr and the distillation column top temperature is 80 to 270 ° C.

Prior to the distillation separation, it is preferable that the alcohol remaining in the esterification reaction liquid is removed in advance by a known method such as fractional distillation or evaporation. In particular, when performing distillation separation using a precision distillation apparatus, it is preferable to perform this operation.

Further, before the distillation separation, if necessary,
It is preferable to remove salts generated by the neutralization treatment of the acid catalyst from the esterification reaction solution. The salt can be removed, for example, by washing or extracting the esterification reaction solution with water. The amount of water used in this case is preferably an amount capable of dissolving the salt, but is usually 0.2 volumes or more, more preferably 0.3 to 5 volumes, particularly 1 to 1 volume of the esterification reaction solution. The capacity may be 0.4 to 3 volumes. The temperature may be from 10 to 90C, more preferably from 30 to 80C.
The water used is preferably water having a low metal ion content (ion-exchanged water, distilled water, etc.).

(3) Third Step In the present invention, next, the ester of 7-cyanoundecanoic acid and / or 2-butyl-7-distillate separated in the second step.
The step of hydrolyzing the ester of cyanoheptanoic acid in the presence of an alkaline compound to form a salt of 2-butyloctanediacid is performed.

As the alkaline compound, an alkaline alkali metal compound, an alkaline alkaline earth metal compound or the like is used alone or in combination. The amount of the alkaline compound used is 2 to 20 times, more preferably 3 to 10 times, especially 3 to 8 times the total of the ester of 7-cyanoundecanoic acid and the ester of 2-butyl-7-cyanoheptanoic acid. Preferably it is molar. The alkali metals include lithium, sodium, potassium and the like, and the alkaline earth metals include calcium, magnesium and the like.

Specific examples of the alkaline alkali metal compound include the above-mentioned alkali metals such as lithium metal, sodium metal and potassium metal, sodium hydroxide, and the like.
Hydroxides of the alkali metals such as potassium hydroxide, alcoholates of the alkali metals such as sodium methylate, sodium ethylate, potassium methylate, potassium ethylate, and hydrides of the alkali metals such as sodium hydride Is mentioned.

Examples of the alkaline alkaline earth metal compound include the alkaline earth metal such as magnesium metal, the hydroxide of the alkaline earth metal such as magnesium hydroxide and calcium hydroxide, and the like. Examples of the alkaline earth metal alcoholates such as magnesium ethylate and the like, and Grignard reagents such as methyl magnesium bromide and the like are included. Among these alkaline compounds, hydroxides of alkali metals (particularly, sodium hydroxide and potassium hydroxide) are preferred.

In the hydrolysis in the third step, the alkaline compound may be used as it is (in a solid state) or may be used in the form of an aqueous solution. The concentration of the aqueous solution is not particularly limited as long as the amount of water used falls within the range described below. The timing of addition of the alkaline compound is not particularly limited, and it may be added to water at the same time as the ester, or may be added to a mixture of the ester and water.

The water used in the hydrolysis in the third step is not particularly limited, but when 2-butyloctanediacid having a low metal ion content is obtained, water having a low metal ion content (ion-exchanged water, distillation Water). The amount of water used is 0.5 to 15 parts by weight, preferably 3 to 1 part by weight, based on 1 part by weight of the total of 7-cyanoundecanoic acid ester and 2-butyl-7-cyanoheptanoic acid ester.
It is preferably 0 parts by weight, particularly preferably 4 to 7 parts by weight.

The hydrolysis temperature is preferably from 60 to 200 ° C., more preferably from 80 to 150 ° C., particularly preferably from 90 to 140 ° C. The pressure at this time is not particularly limited, but when the hydrolysis temperature is 100 ° C. or higher, the pressure is preferably 1 to 10 atm to suppress evaporation of water and the like. The reaction atmosphere is not particularly limited, and may be air or an inert gas atmosphere such as nitrogen. The time required for the hydrolysis varies depending on the reaction conditions such as the temperature and the amount of the reaction solution, but is usually 0.5 to 50 hours. In addition, it is preferable to remove ammonia and alcohol generated during the hydrolysis outside the reaction system.

(4) Fourth Step In the present invention, a step of subjecting the hydrolysis reaction solution obtained in the third step to acid treatment to form 2-butyloctanediacid is then performed. Examples of the acid used at this time include inorganic acids such as hydrochloric acid, sulfuric acid and phosphoric acid, and organic acids such as formic acid, acetic acid, oxalic acid, benzenesulfonic acid and p-toluenesulfonic acid. Among these, inorganic acids are preferred, and among them, sulfuric acid is particularly preferred. The amount of the acid used is appropriately determined according to the pH at the time of treatment, and the acid may be used as it is without dilution, or may be diluted with water.

In the acid treatment, an acid is added to the hydrolysis reaction solution obtained in the third step, and the pH of the reaction solution is preferably adjusted to 4
Hereinafter, more preferably 1 to 3.5, particularly preferably 1 to 3.5.
3 is maintained. The temperature at this time is 1
The temperature is preferably 5 to 100C, more preferably 35 to 70C. The time required for the acid treatment varies depending on the pH and the amount of the acid treatment, but is usually about 5 minutes to 20 hours.
The atmosphere of the acid treatment is not particularly limited, and may be usually in the air.

The produced 2-butyloctanediacid is quaternary
It is separated from the acid treatment solution obtained in the step, for example, by extraction. For this extraction, a good solvent of 2-butyloctanediacid is used, and water and a heterogeneous layer (particularly, an organic solvent layer and an aqueous layer are used).
Layer) (which forms a heterogeneous layer when mixed with water) is preferably used.

Examples of the organic solvent include aromatic hydrocarbons such as benzene, toluene, xylene, ethylbenzene and isopropylbenzene, aromatic halogenated hydrocarbons such as chlorobenzene, and C4 to C15 such as methyl ethyl ketone and methyl isobutyl ketone. And ketones of 6 to 16 carbon atoms such as diisopropyl ether, dibutyl ether and ethylene glycol diethyl ether. The amount of organic solvent used is acid treatment liquid 1
0.1 volume or more with respect to the volume, further 0.1 to 5 volumes,
In particular, the capacity is preferably 0.2 to 3 volumes.

The extraction is carried out by bringing the acid-treated solution and the organic solvent into contact at a predetermined ratio. The temperature at this time is 1
The temperature is preferably from 0 to 100C, more preferably from 30 to 90C. The time required for the extraction varies depending on the temperature at the time of the extraction and the amount of the organic solvent used, but is usually about 5 minutes to 20 hours. The contact between the acid treatment liquid and the organic solvent is performed by, for example, countercurrent contact, contact with a stirring tank, or the like. The atmosphere in this step is not particularly limited.

The extracted 2-butyloctanediacid can be obtained by separating the organic solvent layer (extract) by liquid separation or decantation and removing the organic solvent from the extract. The removal of the organic solvent is performed by a known method such as fractional distillation or evaporation. The atmosphere at this time is not particularly limited.

As described above, from 7-cyanoundecanoic acid and / or 2-butyl-7-cyanoheptanoic acid,
High-purity (substantially free of 1,10-dodecanedioic acid) 2-butyloctanedioic acid can be produced.

When 2-butyloctanediacid having a higher purity (containing less acid and metal) is to be obtained, the organic solvent layer (extract) obtained by the extraction is removed before removing the organic solvent. Washing with water is preferred. The water washing is performed, for example, by adding water to the organic solvent layer with stirring to transfer water-soluble impurities (such as an acid used for the acid treatment, a metal derived from a raw material or an apparatus) to the aqueous layer. Washing is usually 2
It is preferable that the temperature be repeated up to 3 times.
At 80 ° C., the time is 1 minute to 10 hours each time, and moreover 2 hours.
It is preferable to be about 0 minute to 5 hours. In addition, the amount of water used is 0.05 volumes or more per 1 volume of the organic solvent layer,
Further, the volume is preferably 0.05 to 5 volumes, particularly preferably 0.1 to 3 volumes. In addition, it is preferable to use water (ion exchange water, distilled water, etc.) with a small metal ion content for water washing.

In the water washing, a water-soluble chelating agent may be added to water for efficient removal of metal impurities. Examples of such a chelating agent include ethylenediaminetetraacetic acid and nitrilotriacetic acid.
Further, the chelating agent may be added to the organic solvent used in the extraction. In this case, dimethylglyoxime, acetylacetone, crown ether and the like can also be used as a chelating agent.

Further, in order to obtain 2-butyloctanediacid of higher purity, it is preferable to purify the 2-butyloctanediacid obtained by the extraction by distillation or crystallization. In particular, when a poorly water-soluble chelating agent is used by adding it to an organic solvent, it is preferable to perform this operation. For crystallization, an aliphatic hydrocarbon such as pentane, hexane, heptane, octane, or a mixed solvent of water and methanol is used.

[0039]

Next, the present invention will be specifically described with reference to examples and comparative examples. The analysis was performed by gas chromatography.

Example 1 40 g of 7-cyanoundecanoic acid was placed in a 1 L (liter) stainless steel reactor equipped with a thermometer, a reflux condenser and a stirrer.
250 g of a raw material containing 25% by weight of 2-butyl-7-cyanoheptanoic acid and 30% by weight of 11-cyanoundecanoic acid, 326 g of 2-propanol, and 96% by weight.
44% by weight of sulfuric acid was added and uniformly stirred and mixed. The liquid mixture was heated with stirring to raise the liquid temperature to 88 ° C (bath temperature 115 ° C). Then, esterification was carried out at the same temperature for 10 hours while extracting the produced water together with azeotropic 2-propanol from the outlet of the reflux condenser.

The obtained esterification reaction solution was cooled to 30 ° C., 46 g of sodium carbonate was added, and the mixture was stirred at the same temperature for 1 hour. Next, the remaining 2-propanol was removed with a rotary evaporator, 579 g of ion-exchanged water was added, and the mixture was stirred at 60 ° C. for 30 minutes, and then separated to obtain 288 g of an esterification reaction solution. Analysis of the reaction mixture revealed that 7-cyanoundecanoic acid ester and 2-butyl-
An ester of 7-cyanoheptanoic acid was detected.

Then, the obtained esterification reaction solution was subjected to precise distillation using a packed column type distillation apparatus having 50 theoretical plates (pressure: 1.2 to 1.6 torr, column top temperature: 137).
１４２142 ° C., reflux ratio 20), to obtain 84 g of a mixture of an ester of 7-cyanoundecanoic acid and an ester of 2-butyl-7-cyanoheptanoic acid.

Next, 21.7 g of the above ester mixture and a 50% by weight aqueous sodium hydroxide solution 2 were placed in a 300 ml stainless steel reactor equipped with a thermometer, a reflux condenser and a stirrer.
8.9 g and 22.6 g of ion-exchanged water were added and uniformly stirred and mixed. This mixture was heated while being stirred in a nitrogen gas atmosphere, and the liquid temperature was 112 ° C (bath temperature 130 ° C).
Temperature. Then, hydrolysis was performed at the same temperature for 24 hours while extracting the produced ammonia and 2-propanol from the outlet of the reflux condenser.

After the obtained hydrolysis reaction solution was cooled to 50 ° C., a 62% by weight aqueous sulfuric acid solution was added to the reaction solution with stirring until the pH reached 1.5, followed by stirring for 1 hour to carry out acid treatment. Was done. During the addition of the aqueous sulfuric acid solution and the acid treatment, the liquid temperature was maintained at around 50 ° C.

After the acid treatment was completed, 32.4 g of toluene was added to the obtained acid-treated solution with stirring, the acid-treated solution was stirred at 70 ° C. for 30 minutes, and the organic solvent layer was separated by liquid separation. Next, 33.4 g of ion-exchanged water and 4.8 g of ion-exchanged water containing 0.096 g of ethylenediaminetetraacetic acid were added to the organic solvent layer with stirring, and the mixture was stirred at 40 ° C. for about 30 minutes to separate the organic solvent layer. Separated. This operation was repeated twice, and further washed twice with 38.2 g of ion-exchanged water. Then, toluene was removed from the organic solvent layer by a rotary evaporator to obtain 14.4 g of 2-butyloctanedioic acid. The purity of the obtained octane diacid is 99.8% by weight,
0-dodecandioic acid was not detected.

Example 2 The amount of 2-propanol was changed to 163 g, and the liquid temperature was adjusted to 98.
C. (bath temperature 115.degree. C.), except that esterification was carried out in the same manner as in Example 1. After completion of the reaction, 284 g of an esterification reaction solution was obtained in the same manner as in Example 1, and the reaction solution was analyzed. The ester of 7-cyanoundecanoic acid and 2-ester were analyzed.
Esters of butyl-7-cyanoheptanoic acid were detected.

Then, precision distillation was carried out in the same manner as in Example 1 to obtain an ester of 7-cyanoundecanoic acid and 2-butyl-
82 g of a mixture of esters of 7-cyanoheptanoic acid were obtained.

Next, 21.4 g of the ester mixture, 28.9 g of a 50% by weight aqueous sodium hydroxide solution, and 33.3 g of ion-exchanged water were charged into the same reactor as in Example 1, and uniformly stirred and mixed. The mixture was heated while stirring under a nitrogen gas atmosphere, and the temperature of the mixture was raised to 98 ° C. (bath temperature 1).
(10 ° C.). Then, hydrolysis was performed in the same manner as in Example 1.

Next, the obtained hydrolysis reaction solution was heated at 40 ° C.
The acid treatment was carried out in the same manner as in Example 1 except that the temperature was kept at about 40 ° C. by cooling to the temperature. After completion of the acid treatment, 52.8 g of toluene was added to the obtained acid-treated solution with stirring, the acid-treated solution was stirred at 70 ° C for 30 minutes, and the organic solvent layer was separated by liquid separation. Next, 33.4 g of ion-exchanged water was added to the organic solvent layer with stirring, the mixture was stirred at 45 ° C. for about 30 minutes to wash the organic solvent layer, and the organic solvent layer was separated by liquid separation. After repeating this operation three times, toluene was removed from the organic solvent layer by a rotary evaporator to obtain 12.9 g of 2-butyloctanediacid. The purity of the obtained octane diacid was 98.5% by weight, and 1,10-dodecane diacid was not detected.

[0050]

According to the present invention, 7-cyanoundecanoic acid and / or 2-butyl-7-cyanoheptanoic acid (especially when a raw material containing a large amount of 11-cyanoundecanoic acid is used) can be used to obtain high-purity. It is possible to produce 2-butyloctanedioic acid (particularly substantially free of 1,10-dodecanedioic acid).

Claims (4)

[Claims] (1) esterifying 7-cyanoundecanoic acid and / or 2-butyl-7-cyanoheptanoic acid,
(2) 7-cyanoundecanoic acid ester and / or 2-butyl-7-cyanoheptanoic acid ester are separated by distillation from the esterification reaction solution, and (3) the ester is hydrolyzed in the presence of an alkaline compound. (4) A method for producing 2-butyloctanedioic acid, which comprises producing a salt of 2-butyloctanedioic acid and (4) treating the hydrolysis reaction solution with acid to produce 2-butyloctanedioic acid. 2. The method for producing 2-butyloctanediacid according to claim 1, wherein the hydrolysis is carried out with an acid while maintaining the pH of the hydrolysis reaction solution at 4 or less. 3. 7-cyanoundecanoic acid and / or 2-
The method for producing 2-butyloctanedioic acid according to claim 1, wherein butyl-7-cyanoheptanoic acid is esterified by reacting with 2-propanol. 4. The method according to claim 1, wherein 2-butyloctanediacid is extracted from the acid-treated solution with an organic solvent, and then the organic solvent is removed from the extract to obtain 2-butyloctanediacid. The method for producing 2-butyloctanediacid according to the above.