JPS6133820B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an α-amino-ε-caprolactam chloroform adduct and a method for producing the same.

α-Amino-ε-caprolactam is known as a raw material for the synthesis of lysine, an essential amino acid.
In addition to this, α-amino-ε-caprolactam is an extremely useful compound that has the potential to be developed into a variety of other uses in the future by taking advantage of its properties as an organic amine. However, since α-amino-ε-caprolactam has an extremely active amino group, it is easily contaminated by air and has the disadvantage of being difficult to store stably.
The drawback was that the reactivity was too high when used as a raw material.

As a result of intensive research on α-amino-ε-caprolactam, the present inventors found that α-amino-ε-caprolactam forms an adduct with chloroform, and that this adduct cannot be isolated as a crystal. The inventors have discovered that the present invention is a useful new substance that does not have the above-mentioned drawbacks, and that they have found advantageous production conditions.

That is, the present invention provides a crystalline adduct in which 1 mole of chloroform is bonded to 1 mole of α-amino-ε-caprolactam, and a crystalline adduct in which 1 mole of α-amino-ε-caprolactam and chloroform are combined in a molar ratio of 1:(1
The method for producing the above-mentioned adduct consists of contacting the adduct at 30° C. or below, followed by crystallization and separation at 30° C. or below.

The crystalline adduct of the present invention is a white crystal with a melting point of 31°C. According to elemental analysis and NMR spectroscopy, this adduct is α-amino-ε-
Caprolactam and chloroform in a molar ratio of 1:1
It is a substance formed by bonding with. In addition, from the values of the chemical shift of the amino group of α-amino-ε-caprolactam, the chemical shift of the hydrogen of the amino group, the chemical shift of the hydrogen of chloroform, and the chemical shift of the hydrogen of chloroform in the adduct, the hydrogen of chloroform was determined by NMR spectroscopy. is α-amino-ε-
It is presumed to be bonded to the amino group of caprolactam.

Although the adduct of the present invention is stable below 30°C,
The binding force between α-amino-ε-caprolactam and chloroform is thought to be relatively small, and for example, by heating this adduct, chloroform can be easily desorbed and α-amino-ε-caprolactam can be recovered. can.

The adduct of the present invention can be produced by bringing α-amino-ε-caprolactam and chloroform into contact, usually in a liquid phase. In this case, it is preferable to use a solvent capable of dissolving both or an excess of chloroform. Although the quantitative ratio of α-amino-ε-caprolactam and chloroform does not affect the composition of the adduct produced, in order to increase the yield of adduct crystals, it is necessary to use chloroform relative to α-amino-ε-caprolactam. It is preferable to use an equimolar amount or more. As a solvent capable of dissolving both α-amino-ε-caprolactam and chloroform, for example, aliphatic alcohols having 2 or more carbon atoms can be used.
In order to produce an adduct of α-amino-ε-caprolactam and chloroform, it is necessary that the α-amino-ε-caprolactam be present in free form upon contact with chloroform. Therefore,
If an acid is present in the system, it must be neutralized with an alkali such as ammonia. On the other hand, even if an alkali such as ammonia is present in the system, it does not hinder the formation of adducts. The reaction temperature is not particularly limited, but is usually selected within the range of 0 to 60°C depending on the amount of chloroform and the amount of solvent used relative to α-amino-ε-caprolactam. Further, the reaction time may be several minutes or more if sufficient stirring is performed.

The adduct of the present invention produced in the liquid phase can usually be separated as crystals by distilling off excess chloroform or solvent and lowering the temperature of the system to 30°C or less. In order to efficiently separate the adduct, the amount of excess chloroform or solvent is preferably 1.5 times or less, preferably 1 time or less, based on the weight of the adduct.

The adduct of the present invention has excellent crystallization properties and can be easily purified by repeated crystallization. Furthermore, as mentioned above, chloroform can be released relatively easily to form α-amino-ε-caprolactam. For example, chloroform can be released by simply heating the adduct to 65°C or by placing it under reduced pressure of about 20 mmHg.

Therefore, by utilizing the properties of the adduct of the present invention, α-amino-ε-caprolactam can be highly purified.

That is, chloroform is added to crude α-amino-ε-caprolactam to form a 1:1 adduct, which is collected as crystals, and then chloroform is released by some means to produce purified α-amino-ε-caprolactam. can be recovered. A high degree of purification of α-amino-ε-caprolactam is particularly important when this compound is used as a lysine raw material.

The adducts of the present invention also include various α-amino-ε-
It can also be used as a raw material in the production of caprolactam derivatives (for example, compounds known to have antifungal effects).

In the adduct of the present invention, the amino group of .alpha.-amino-.epsilon.-caprolactam, which is originally very active, is in a form in which the reactivity is moderately suppressed, which is advantageous when used as a raw material. or α−
Amino-ε-caprolactam has a very active amino group, so if it is stored in the air for a long period of time, it becomes partially impure and becomes colored, which is a problem, as is the case with organic amines such as cyclohexylamine. However, the adduct of the present invention has the activity of the amino group moderately suppressed and is stable upon storage. Sani also has the advantage of having a melting point of 31°C, so it can be handled as a crystal at room temperature.

The present invention will be specifically explained below using Examples.

Example 1 α-Amino-ε-caprolactam 12.8g (0.10g
mol) and 17.9 g (0.15 mol) of chloroform in a 200 ml volume 3 equipped with a stirrer, reflux condenser, and thermometer.
Pour into a neck flask and warm in a hot water bath to bring the internal liquid to 40℃.
Stir for 15 minutes while maintaining After this, switch the hot water bath to an ice water bath, and cool the liquid in the three-necked flask to 10°C.
When the mixture was slowly cooled to , white crystals were precipitated. The entire amount of the liquid in the three-necked flask was taken out and filtered to obtain 19.2 g of crystals.

The melting point of this crystal was 31°C, and the analysis values by gas chromatography showed that it contained 51.5% by weight of α-amino-ε-caprolactam and 48.5% by weight of chloroform. This analysis result is the calculated value when α-amino-ε-caprolactam and chloroform are combined at a molar ratio of 1:1 (α-amino-ε-caprolactam
(51.78 wt%, chloroform 48.22 wt%).

The elemental analysis results of this result are C: 33.83%, H:
5.18%, N: 11.21%, 0: 6.91%, Cl: 42.87%
It was hot. This result is a calculated value when α-amino-ε-caprolactam and chloroform are combined at a molar ratio of 1:1 (C: 33.96%, H: 5.30%, N:
11.32%, O: 6.46%, Cl: 42.96%).

The NMR spectrum of this crystal is α-amino-
The proton ratio of ε-caprolactam and chloroform is 12:1, indicating that it is a crystal in which α-amino-ε-caprolactam and chloroform are bonded in a molar ratio of 1:1, and the chemical shift of the hydrogen of the amino group is δ2. .1, the chemical shift of hydrogen in chloroform is δ
It showed 7.6. This chemical shift is α-amino-
In the NMR spectra of ε-caprolactam and chloroform alone, the chemical shift of the hydrogen of the amino group is δ1.5, which is different from the chemical shift of the hydrogen of chloroform, δ7.4.
This suggests the possibility that it is bonded to the amino group of -amino-ε-caprolactam.

10 g of crystals of the adduct obtained above were placed in a vacuum desiccator, and the system was kept at 10 mmHg for 3 hours to obtain 4.6 g of white crystals. The analysis value of α-amino-ε-caprolactam by gas chromatography of this crystal is
99.6% by weight, and the IR spectrum shows α-amino-
The spectrum completely matched that of ε-caprolactam.

Example 2 α-amino-ε-caprolactam 12.8g (0.10
), 11.9 g (0.10 mole) of chloroform, and 3 ml of ethyl alcohol were mixed, and after blowing in a small amount of ammonia gas, the mixture was charged into the three-necked flask of Example 1 and stirred at 25° C. for 30 minutes. Next, the internal solution was cooled to 5° C., and the entire solution was filtered to obtain 18.7 g of white crystals.

The melting point of this crystal is 31℃, and the gas chromatography analysis results show that it is α-amino-ε-caprolactam.
51.6% by weight, and 48.4% by weight of chloroform.
Moreover, the NMR spectrum was the same as that of the crystal obtained in Example 1.

Example 3 25 g of the 1:1 crystalline adduct (white crystals) of α-amino-ε-caprolactam and chloroform obtained as the product in Example 1 and α-amino-ε-
25 g of caprolactam (white crystals) were each stored in a sample bottle at room temperature for 30 days. α-Amino-ε-caprolactam and chloroform 1:1
The crystalline adduct remained as white crystals (50%
APHA in aqueous solution = 100), and α-amino-ε-caprolactam turned yellow (in 50% aqueous solution).
APHA=3000).

Example 4 100% α-aminocyclohexanone oxime
Crude CLA obtained by Beckmann rearrangement in sulfuric acid
(Purity 95.2%) 15 g was placed in a 200 ml three-necked flask, 15 ml of chloroform was added, and the mixture was dissolved at 30°C. When this solution was stirred for 30 minutes while being kept at 0°C, crystals were precipitated. The resulting slurry was filtered using a centrifuge to obtain 19.5 g of white crystals. The composition of this crystal was determined by gas chromatography and was found to be α-amino-ε-caprolactam: 50.8
%, and chloroform 49.2%. This crystal 15.0
g was dissolved in 15 ml of water, and the resulting aqueous layer was concentrated to dryness under reduced pressure to obtain 7.6 g of crystals. CLA in this crystal
The purity was determined by gas chromatography and was 99.7%.

Claims (1)

[Claims] 1. A crystalline adduct consisting of 1 mole of chloroform bound to 1 mole of α-amino-ε-caprolactam. 2 α-Amino-ε-caprolactam and chloroform are brought into contact with each other at a molar ratio of 1: (1 or more), and then crystallized and separated at 30°C or lower.
-Production method of amino-ε-caprolactam/chloroform crystalline adduct.