JP2649736B2 - Purification of lactam-containing organic solutions - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a method for purifying a lactam-containing organic solution. More specifically, “mainly 1
Organic solution containing species or more lactam components "
The present invention relates to a method for efficiently separating and purifying an active ingredient contained in an organic solution by extracting water with water.

The method of the present invention is a method for simultaneously producing ε-caprolactam and ω-dodecane lactam by a so-called “colactamization method”, wherein the lactam and water-based “lactam oil” are extracted with an organic solvent. The obtained organic solution (extract) is preferably used for separating ε-caprolactam and ω-dodecanelactam by back-extraction treatment with water.

[Description of Prior Art]

As a method for simultaneously producing ε-caprolactam and ω-dodecanelactam, cyclohexanone and cyclododecanone are oximed together as a mixture, and the resulting mixture of cyclohexanone oxime or a salt thereof and cyclododecanone oxime or a salt thereof is sulfated. Or Beckmann rearrangement in the presence of fuming sulfuric acid, followed by neutralization with ammonia gas or aqueous ammonia to obtain a lactam mixture,
The lactam mixture is extracted with an organic solvent immiscible with water, or the lactam oil layer separated from the aqueous ammonium sulfate layer by phase separation of the lactam mixture is extracted with an organic solvent immiscible with water. An extract containing the components is obtained, and the extract is back-extracted with water to transfer ε-caprolactam to the aqueous layer, while leaving ε-dodecanelactam in the organic solvent layer (so-called “colactamization method”). ] Is known as a known technique (for example, JP-B-46-7254, JP-B-46-1016).
No. 8).

In the simultaneous production method of ε-caprolactam and ω-dodecanelactam by the “colactamization method”, conventionally,
The lactam mixture or the lactam oil layer is subjected to extraction treatment with an organic solvent, and an organic solvent solution (extract) containing a lactam component such as ε-caprolactam or ω-dodecane lactam.
And water (heavy solution) containing water-soluble impurities, and then the extract was subjected to water extraction as it is. However, in the extraction of the lactam component with the organic solvent, one of the heavy solution was contained in the extract. Because of the entrainment, an emulsion is formed during the next water extraction, which tends to cause poor separation between the organic solvent layer and the aqueous layer. Becomes cloudy with the accompanying organic matter, and ε
-Adversely affect the quality of caprolactam or
Water-soluble impurities accompany the organic solvent layer, which adversely affects the quality of ω-dodecanelactam.

[Problems to be solved by the invention]

An object of the present invention is to cause an organic solution containing water-soluble impurities as a heavy liquid and containing one or more lactams with water when the organic solution is subjected to extraction treatment with water. Prevents the formation of emulsion, efficiently transfers and separates the target component from the organic solution to the aqueous solution,
It is an object of the present invention to provide an industrially suitable method for purifying a lactam-containing organic solution that can obtain an active ingredient with high quality and high yield.

[Means for solving the problem]

The present inventors have found that mainly ε-caprolactam and ω-
From an organic solution containing dodecane lactam, as a result of diligent research to improve the various disadvantages described above in the method of transferring and separating ε-caprolactam to an aqueous layer by water extraction, as a result of the water extraction, The inventor of the present invention found that the formation of the emulsion was caused by "water containing water-soluble impurities (heavy liquid)" present in the lactam-containing organic solution during the water extraction, and completed the present invention.

That is, the present invention provides a water-soluble impurity, and a lactam oil containing at least one lactam is subjected to an extraction treatment with an organic solvent immiscible with water, and then the obtained organic solution is cooled to remove heavy liquid. The present invention relates to a method for purifying a lactam-containing organic solution, comprising separating the target component on the organic solution side into an aqueous solution side by subjecting the obtained organic solution to back extraction with water after separation and removal.

[Detailed description of each requirement of the present invention]

 Hereinafter, the method of the present invention will be described in detail.

In the present invention, water containing water-soluble impurities as a heavy liquid, and ε-caprolactam and ω as active ingredients are used.
A lactam such as dodecane lactam, and optionally an organic solution further containing an organic solvent is subjected to extraction treatment with water, whereby one or more of the active ingredients (lactams) present on the organic solution side are extracted. Upon transferring and separating the above to the aqueous solution side, prior to the water extraction, by cooling the organic solution, separating and removing heavy liquid as impurities, to efficiently perform the water extraction,
Especially characteristic.

Further, in a preferred embodiment of the present invention, cyclohexanone and cyclododecanone are oximized together as a mixture, and the resulting mixture of cyclohexanone oxime or a salt thereof and cyclododecanone oxime or a salt thereof is treated in the presence of sulfuric acid or fuming sulfuric acid. Beckmann rearrangement, then neutralized with ammonia gas or aqueous ammonia to obtain a lactam mixture mainly containing ε-caprolactam, ω-dodecane lactam and ammonium sulfate, and the lactam mixture was directly extracted with a water-immiscible organic solvent. Or leaving the lactam mixture to stand,
-After phase separation into a lactam oil layer containing caprolactam and ω-dodecane lactam and an aqueous layer mainly containing ammonium sulfate, the lactam oil layer is subjected to extraction treatment with an organic solvent immiscible with water to separate heavy liquid. As a result, an organic solvent solution containing a lactam component such as ε-caprolactam and ω-dodecane lactam (hereinafter referred to as “organic solution”) is further back-extracted with water to convert ε-caprolactam into water. Layer, while ω-dodecanelactam remains in the organic solution layer to form ε-caprolactam and ω-
After separation from dodecane lactam, each of the aqueous layer containing ε-caprolactam and the organic solution layer containing ω-dodecane lactam are purified by distillation and other conventional methods to obtain ε-caprolactam and ω-. In the "colactamization method" for simultaneously producing dodecane lactam, the organic solution obtained by extracting the "lactam mixture or lactam oil layer" (hereinafter, referred to as "lactam oil") with an organic solvent is cooled before back-extraction treatment with water. By performing the treatment, the heavy liquid is sufficiently separated from the organic solution, and in the subsequent water extraction, ε-caprolactam migrating to the aqueous layer is efficiently converted from ω-dodecane lactam remaining in the organic solution layer. They can be separated.

The above-mentioned lactam oil obtained by the Beckmann rearrangement of oximes formed by oximation of cyclohexanone and cyclododecanone and the subsequent neutralization includes, in a subsequent step, an organic solvent obtained by extracting the lactam oil with an organic solvent. The solution is back-extracted with water and ε
-When transferring and separating caprolactam into the aqueous layer, there is a `` heavy liquid '' as described below, which causes an emulsion to be generated and causes a separation failure between ε-caprolactam and ω-dodecanelactam. According to the method of the present invention,
As described above, by cooling the organic solution prior to the water extraction, the heavy liquid can be removed to the extent that no emulsion is generated any more.

In the present invention, examples of the water-soluble impurities contained in the lactam oil include ammonium sulfate and water-soluble organic impurities. Examples of water-soluble organic impurities include decyl sulfate or decyl sulfate, undecyl sulfate or undecyl sulfate, alkyl sulfate or alkyl sulfate such as dodecyl sulfate or dodecyl sulfate, amino acid salts such as sodium aminocaproate, and fatty acids. Specific examples include anionic surfactants such as salts, alkylsulfonates, and alkylarylsulfonates. Ammonium salts are preferred as the alkyl sulfates.

The presence of these anionic surfactants depends on the presence of raw materials such as cyclohexanone and cyclododecanone, especially linear alkyl alcohols such as n-decyl alcohol, n-undecyl alcohol and n-dodecyl alcohol contained in cyclododecanone. Or from a branched-chain alkyl alcohol, etc., from cyclohexanone and cyclododecanone, through an oximation step, a rearrangement step and a neutralization step, the lactam mixture containing mainly ε-caprolactam and ω-dodecane lactam. When you get
These linear or branched alkyl alcohols react with sulfuric acid or fuming sulfuric acid to produce the above-mentioned alkyl sulfate (or alkyl sulfate).

In the present invention, ε-caprolactam, ω
A lactam mixture containing dodecane lactam and ammonium sulfate, or a lactam oil layer containing mainly ε-caprolactam and ω-dodecane lactam, separated from the aqueous ammonium sulfate layer by phase separation of the lactam mixture; , And then subjecting the obtained organic solution to a cooling treatment, thereby separating and removing heavy liquid from the obtained organic solution to obtain ε-caprolactam and ω-
The content of dodecane lactam is 10-20% by weight in both cases.
It is preferred that

If the content of ε-caprolactam and ω-dodecanelactam in the organic solution is less than the above-mentioned amount, the organic solution is extracted with water to transfer and separate ε-caprolactam in the organic solution into an aqueous layer. In this case, a large amount of water is required.Therefore, in order to recover ε-caprolactam from the ε-caprolactam aqueous solution obtained by this oil removal, a large amount of energy is required when the ε-caprolactam aqueous solution is concentrated and purified. And the water extraction is disadvantageous in that a high-stage extraction device is required, while the content of ε-caprolactam and ω-dodecanelactam in the organic solution exceeds the above-mentioned amounts. During the water extraction, crystals of ω-dodecane lactam are precipitated, which is not preferable in any case.

In the present invention, the “lactam mixture or lactam oil layer”, that is, the “heavy liquid” contained in the “lactam oil” includes, in addition to the aforementioned “water-soluble impurities such as ammonium sulfate and anionic surfactants”, An aqueous solution containing a small amount of a lactam component such as ε-caprolactam or ω-dodecane lactam, most of which are present in a form dissolved in the lactam oil, and extracted by extracting the lactam oil with an organic solvent. And an organic solvent extract containing a lactam component such as ε-caprolactam and ω-dodecanelactam.

Examples of the organic solvent used in the present invention include aromatic hydrocarbons such as benzene, toluene, xylene and isopropylbenzene, alicyclic hydrocarbons such as cyclohexane and cyclooctane, n-hexane, n-heptane and n-hexane. Solvents which are liquid at the extraction temperature such as aliphatic hydrocarbons having 6 to 8 carbon atoms such as octane, hydrocarbons substituted with halogen atoms such as trichloroethylene, carbon tetrachloride, and chloroform, and which are immiscible with water. Among them, benzene and toluene can be most preferably mentioned. It goes without saying that it is possible to use a mixture of two or more of the above solvents.

The extraction of the lactam oil with an organic solvent is carried out in a liquid-
Naturally, it is preferable to carry out the liquid extraction. However, the extraction operation conditions such as the extraction temperature, the extraction agent ratio and the extraction time, and the extraction method such as the type of the extraction device in this extraction are the usual liquid-liquid extraction methods. The content of ε-caprolactam and ω-dodecane lactam in the organic solution obtained as a result of the extraction and subsequent cooling is not particularly limited as long as it is within the range applicable in the extraction.
The extraction operation conditions and the extraction method may be determined so as to fall within the above range of 10 to 20% by weight. For example, regarding the extraction temperature, in the extraction device, it is the temperature at which the lactam oil or the organic solvent exists as a liquid,
It is desirable that the temperature range is not lower than the melting point of the lactam oil and not higher than the boiling point of the "extract or heavy liquid described above" obtained as a result of the extraction, preferably about 60 to 80C. As the extraction device, it is industrially preferable to use a countercurrent liquid-liquid extraction device such as a packed tower or a perforated plate type tower.

Next, as described above, a lactam component such as ε-caprolactam and ω-dodecane lactam as an active ingredient, such as the aforementioned “organic solution obtained by extracting lactam oil with an organic solvent”, which is a feature of the present invention, is used. The cooling treatment of the “containing organic solution (lactam-containing organic solution)” will be described.

As described above, in the method of the present invention, the lactam-containing organic solution obtained by extracting the lactam oil with an organic solvent is subjected to a cooling treatment prior to the next water extraction step, and the organic solution is subjected to a cooling treatment. Therefore, the organic solution to be supplied to the water extraction step is such that the heavy liquid in the organic solution does not form an emulsion during water extraction. When the lactam oil is extracted with an organic solvent, it can be obtained by: (a) transferring the heavy liquid separated and generated from the lactam oil to the organic solvent from the lactam oil; After once separating the `` organic solvent extract containing a lactam component such as ε-caprolactam or ω-dodecane lactam '', by cooling the organic solvent extract, Organic solvent extractant to still entrained said heavy liquid (most of which exists in dissolved form in an organic solvent extract)
(B) the aforementioned lactam-containing organic solution obtained by further separating / removing the organic solvent extract, and (b) the heavy liquid produced by the cooling treatment without separating the heavy liquid and the organic solvent extract. Any of the aforementioned “lactam-containing organic solutions” obtained by separating and removing the liquid from the organic solvent extract is possible. However, in the present invention, it is preferable to subject the “lactam-containing organic solution” of (a) to water extraction. Of course, when extracting the lactam oil with an organic solvent, for example, by using a suitable extraction device such as a mixer settler, and appropriately selecting the extraction operation conditions as described above, the lactam component from the lactam oil It is needless to say that the extraction of the heavy liquid and the separation and removal of the heavy liquid from the lactam oil by cooling can be simultaneously performed.

In the present invention, the degree to which “water (heavy liquid) containing water-soluble impurities such as anionic surfactants” in the lactam-containing organic solution is removed by cooling treatment is less than the water-soluble impurities in the lactam oil. Content, the content of the heavy liquid in the lactam-containing organic solution determined by the extraction conditions and the extraction method when extracting the lactam oil with an organic solvent, and the extraction operation conditions in the next water extraction step, etc. In the present invention, the lactam-containing organic solution supplied to the water extraction step is entrained in water-soluble impurities such as anionic surfactants. With water (heavy liquid), it is sufficient that the emulsion is not formed during the water extraction. In general, the heavy liquid is contained in the lactam-containing organic solution supplied to the water extraction step in such an amount that the content of the anionic surfactant in the lactam-containing organic solution is 10 ppm by weight or less. It is preferable that the heavy liquid in the lactam-containing organic solution is finally cooled and separated / removed.

Therefore, in the present invention, the temperature at which the lactam-containing organic solution is cooled before being subjected to the water extraction treatment cannot be specified unconditionally, and the content of the lactam component and the heavy liquid in the lactam-containing organic solution, and It should be determined in consideration of the extraction operation conditions and the like employed in the water extraction step, but generally, it is preferable to cool the lactam oil to a temperature about 5 to 40 ° C. lower than the extraction temperature of the organic solvent with the lactam oil. preferable.

Further, the method of cooling the lactam-containing organic solution is not particularly limited, and a cooler that is usually used industrially may be provided by using the lactam oil-containing organic solvent from the extraction device using an organic solvent to the water extraction device. And a method of cooling with a refrigerant such as cooling water, for example.

In the present invention, on the downstream side of the cooler, further, a stationary separation tank such as a decanter, which is usually used industrially, is provided, and the heavy liquid separated by cooling the lactam-containing organic solution is separated from the lactam-containing organic solution. After being completely separated and removed from the organic solution, it is desirable to supply the obtained organic solution to a water extraction device, and the separated heavy liquid contains ε-caprolactam or ω-dodecane lactam, particularly ε-caprolactam. Since caprolactam is contained in an effective amount, considering the point of enabling commercial production, the separated heavy liquid is returned, for example, to the above-mentioned “lactam oil extraction treatment step with an organic solvent” and the like, and the lactam component is removed. It is needless to say that it is desirable to collect

As described above, during the extraction of the lactam oil with an organic solvent, the extract, that is, the heavy liquid accompanying the lactam-containing organic solution, prior to the next water extraction step, by cooling the lactam-containing organic solution, Although the method of removing has been described, the method of removing the heavy liquid in the lactam-containing organic solution is not limited to this “cooling” treatment method.For example, the lactam-containing organic solution containing the heavy liquid may be used. Of course, a processing method of “heating and concentrating under reduced pressure” is also possible. However, considering the ease of operation and the like, the "cooling" processing method of the present invention is more preferable.

Thus, the lactam-containing organic solution from which the heavy liquid containing the water-soluble impurities such as the anionic surfactant has been removed,
Next, it is subjected to water extraction. The extraction temperature, extraction agent ratio, extraction time, standing time for liquid separation after extraction, extraction operation conditions such as the type of extraction device, extraction method, etc. The method is not particularly limited and may be a method applied in ordinary liquid-liquid extraction.For example, as an extraction device, as in the case of the extraction of lactam oil with an organic solvent, a packed tower or a perforated plate type may be used. It is preferable to use an industrially used countercurrent liquid-liquid extraction device such as a tower.

〔Example〕

Next, the method of the present invention will be specifically described with reference to Examples and Comparative Examples, but the present invention is not limited to the following Examples as long as the purpose is not exceeded.

Example 1 A glass container equipped with a stirrer containing 850 g of an organic substance (hereinafter referred to as "lactam oil") mainly containing 47% by weight of ε-caprolactam, 36% by weight of ω-dodecanelactam and 13% by weight of water (volume 5). Then, 2150 g of toluene was added, and the mixture was stirred and mixed at a temperature of 68 ° C., and 2903 g of a toluene extract containing 13% by weight of ε-caprolactam and 11% by weight of ω-dodecanelactam, and 8.0% by weight of ε- 97 g of a separated heavy liquid containing caprolactam and 0.3% by weight of ω-dodecanelactam were obtained.

320 g of this toluene extract was placed in a glass container having a capacity of 1 and cooled by a water bath to a temperature of 60 ° C. to obtain 2 g of a heavy liquid containing 38% by weight of ε-caprolactam and 1.6% by weight of ω-dodecanelactam. .

Then, this heavy liquid was separated by a separating funnel, and 318 g of the remaining toluene extract was transferred to a glass container with a stirrer having a capacity of 2, 456 g of water was further added, and the mixture was stirred and mixed, and ε-caprolactam was added to the aqueous layer side. The organic phase (toluene phase) containing 12% by weight of ω-dodecane lactam was easily separated by a short standing separation without producing an emulsion.
Aqueous phase containing 278 g and 7.1% by weight of ε-caprolactam
g was obtained.

Comparative Example 1 Back extraction of a toluene extract with water was performed in the same manner as in Example 1 except that the toluene extract was not cooled before the water extraction treatment, and an emulsion was formed, and stirring was stopped. Even after standing for 30 minutes, the organic phase and the aqueous phase could not be separated.

Example 2 Lactam oil containing mainly 43% by weight of ε-caprolactam, 43% by weight of ω-dodecanelactam and 10% by weight of water
1349 g was charged into a glass container (volume 10) equipped with a stirrer, and then 4745 g of toluene was added and mixed by stirring at a temperature of 70 ° C., containing 9.5% by weight of ε-caprolactam and 9.6% by weight of ω-dodecane lactam. 5974 g of toluene extract and 1
21 g of separated heavy liquid was obtained.

When 5974 g of this toluene extract was taken in a glass container having a capacity of 10 and cooled to a temperature of 40 ° C. by a water bath, 48 g of a heavy liquid containing 15% by weight of ε-caprolactam and 0.7% by weight of ω-dodecanelactam was separated, 5925 g of a toluene extract containing 9.4% by weight of ε-caprolactam and 9.7% by weight of ω-dodecanelactam were obtained.

Therefore, 5925 g of the toluene extract obtained after this cooling
To a glass container with a stirrer having a capacity of 10 and further 3000
g of water was added, mixed with stirring, and ε-caprolactam was back-extracted to the aqueous layer side, without the generation of emulsion,
A good separation of the organic phase and the aqueous phase was easily obtained by a short standing separation.

Comparative Example 2 Back extraction of the toluene extract with water was performed in the same manner as in Example 2 except that the heavy extract was not separated from the toluene extract by cooling before the water extraction treatment of the toluene extract. When performed, an emulsion was formed, and the phase separation between the organic phase and the aqueous phase took 15 minutes, and the aqueous phase contained a cloudy emulsion.

[Explanation of operation and effect]

As described above, the method of the present invention employs, as described above, an oximation process, a Beckmann rearrangement process, and a neutralization process from cyclohexanone and cyclododecanone, which simultaneously produce ε-caprolactam and ω-dodecanelactam, as described above. The lactam mixture obtained through the process is subjected to extraction treatment with an organic solvent immiscible with water, and then the obtained lactam-containing organic solution is subjected to water extraction treatment to transfer ε-caprolactam in the lactam-containing organic solution to an aqueous layer. -Separation separated and purified ε-caprolactam and ω-dodecanelactam, but the lactam-containing organic solution contained heavy liquids containing water-soluble impurities such as anionic surfactants. Therefore, in the water extraction step, poor separation between the organic solvent layer and the aqueous layer accompanying the formation of the emulsion is likely to occur, and the A large extraction tower is required, and the organic matter accompanies the water layer and becomes cloudy, adversely affecting the quality of ε-caprolactam, and conversely, water-soluble impurities accompany the organic solvent layer, While problems such as adversely affecting the quality of ω-dodecane lactam have occurred, heavy-liquid separation by cooling the lactam-containing organic solution prior to water extraction is performed to form an emulsion in the water extraction step. And (a) preventing the organic layer containing a large amount of impurities from being mixed into the aqueous layer, thereby obtaining high-quality ε-caprolactam. High quality ω, preventing contamination of organic layer
-Can obtain dodecane lactam,
(C) It is possible to prevent a decrease in the extraction efficiency in the water extraction step, to recover ε-caprolactam and ω-dodecanelactam in a high yield, and (d) to perform water extraction by continuous countercurrent extraction. In this case, the treatment can be performed in a column having a small diameter, so that it is possible to use an extraction column having a high number of theoretical plates, and it is expected that the extraction efficiency can be improved from the apparatus and the extraction operation is complicated due to the enlargement of the apparatus. This provides an effect of providing a method for purifying a lactam-containing organic solution that can also eliminate the property.

Continuing from the front page (72) Inventor Kosaku Ohata Examiner, Ube Chemical Plant, Ube Chemical Plant, 1978 Kogushi, Ube City, Ube City, Yamaguchi Prefecture Tamotsu Tominaga (56) References JP-A-57-82365 (JP, A JP-A-50-52079 (JP, A) JP-B-46-7254 (JP, B1) JP-B-46-10168 (JP, B1) JP-B-60-21145 (JP, B2)

Claims (2)

(57) [Claims] A lactam oil containing water-soluble impurities and ε-caprolactam and ω-dodecane lactam is extracted with an organic solvent immiscible with water, and then the obtained organic solution is cooled to obtain A method for purifying a lactam-containing organic solution, comprising separating and removing the liquid, and then subjecting the resulting organic solution to back extraction with water to separate ε-caprolactam from the organic solution into an aqueous solution. 2. An organic solution obtained by extracting lactam oil with an organic solvent immiscible with water is heated at a temperature of 5 to 40 ° C. below the extraction temperature.
The method according to claim 1, wherein the lactam-containing organic solution is cooled to a low temperature.