JPH0597777A - Method for purifying ethyleneamine - Google Patents

Abstract

PURPOSE:To obtain a method for removing an N-alkylated ethyleneamine and pyrazines produced as by-products in producing ethyleneamine. CONSTITUTION:An aqueous solution of ethylene amine is extracted with an organic solvent to separate an N-alkylated ethyleneamine and pyrazines in the organic phase from ethyleneamine in the water solution.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying ethyleneamine. Ethyleneamine is a useful aliphatic amine compound used as a pesticide, a chelating agent, an epoxy curing agent, a wet paper strengthening agent, a lubricating oil additive and the like.

[0002]

2. Description of the Related Art As a method for producing ethyleneamine, a method for producing ethyleneamine from ethylene dichloride and ammonia is known. This method is widely practiced, and it is possible to produce ethylene amine having a small amount of impurities such as N-alkylated ethylene amine and / or pyrazines, but since a large amount of salt is produced as a by-product, this separation is performed. And has the drawback of being expensive to process. Therefore, research has been conducted on methods such as extracting ethyleneamine from an aqueous solution of ethyleneamine containing inorganic salts with an organic solvent and adsorbing and removing ethyleneamine with activated carbon.

In addition to the method using ethylene dichloride as a raw material,
As a method for producing ethyleneamine, a method using monoethanolamine as a raw material is also known. This method
Compared with the method using ethylene dichloride as a raw material, there is no problem of by-product of salt, but there is a problem that impurities such as N-alkylated ethylene amine and pyrazines are produced in a large amount.
N-alkylated ethylene amines and pyrazines reduce the quality of ethylene amines and significantly reduce their field of use. Therefore, it is necessary to separate N-alkylated ethyleneamines and pyrazines from ethyleneamines, but these are difficult to separate by distillation because of their close boiling points.

As a method for producing ethyleneamine, a method using hydrocyanic acid as a raw material has also been studied. However, this method produces a large amount of N-alkylated ethyleneamine, which is difficult to separate from ethyleneamine. Not industrialized.

As described above, a method for industrially separating N-alkylated ethyleneamines and pyrazines contained in ethyleneamine has not been known yet.

[0006]

As described above, a method for purifying ethyleneamine containing N-alkylated ethyleneamine and pyrazines which deteriorates the quality of ethyleneamine has not yet been known.

In particular, N produced as a by-product in the method for producing ethyleneamine using monoethanolamine or hydrocyanic acid as a raw material.
-Purifying ethyleneamines, including alkylated ethyleneamines and pyrazines, is of great industrial significance.

Therefore, it is desired to develop a method for purifying N-alkylated ethyleneamines and ethyleneamines including pyrazines.

[0009]

In view of this situation, the inventors of the present invention have made earnest studies on a method for purifying ethyleneamine, and as a result, extracted an ethyleneamine aqueous solution containing N-alkylated ethyleneamine and pyrazines with an organic solvent. By doing so, the novel fact that N-alkylated ethyleneamine and pyrazines in ethyleneamine can be reduced was found, and the present invention has been completed.

That is, the present invention is a method for purifying ethyleneamine containing N-alkylated ethyleneamine and / or pyrazines, characterized in that an aqueous solution of ethyleneamine is extracted with an organic solvent. Is.

The present invention will be described in more detail below.

In the method of the present invention, N-alkylated ethyleneamines and / or pyrazines in the aqueous ethyleneamine solution are reduced by extraction with an organic solvent.

In the method of the present invention, any organic solvent can be used as long as it can be phase separated from water. As an organic solvent,
Esters such as ethyl acetate and methyl acetate, halogenoalkanes such as chloromethane, dichloromethane, chloroform, carbon tetrachloride and ethylene dichloride, aromatic hydrocarbons such as benzene, toluene and xylene, ketones such as methyl ethyl ketone and diethyl ether. Ethers such as tell, n-
Butanol, isobutanol, sec-butanol, n
-Amyl alcohol, active amyl alcohol, isoamyl alcohol, sec-amyl alcohol, 3-pentanol, tert-amyl alcohol, fusel oil, n
-Hexanol, methylamyl alcohol, 2-ethylbutanol, n-heptanol, 2-heptanol, 3
-Heptanol, n-octanol, 2-octanol, 2-ethylhexanol, 3,5,5-trimethylhexanol, nonanol, n-decanol, undecanol, n-dodecanol, trimethylnonyl alcohol, tetradecanol, heptadecanol, cyclo Alcohols such as hexanol, 2-methylcyclohexanol, benzyl alcohol and phenethyl alcohol can be used, and among them, esters and / or esters capable of selectively extracting N-alkylated ethyleneamine and pyrazines
Alternatively, halogenoalkanes or alcohols are preferable. These organic solvents may be used alone or as a mixture of multiple components.

In the method of the present invention, ethyleneamine is made into an aqueous solution and then extracted with an organic solvent. Conversely, ethyleneamine and an organic solvent may be mixed and then water may be added thereto.

In the method of the present invention, the amount of water added to ethyleneamine is difficult to limit because it greatly changes depending on the type and amount of the organic solvent, but it is not less than the amount required for phase separation with the organic solvent. Should be added.

In the method of the present invention, ethyleneamine means a compound having amino groups at both ends of an ethylene chain, and ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, pentaethylenehexamine, piperazine, N- (2 -Aminoethyl) piperazine and the like are exemplified. Among them, ethylenediamine is required to have high purity, and it is particularly difficult to separate it from N-alkylated ethylenediamine and pyrazines, so that the effect of the present invention is great.

In the method of the present invention, N-alkylated ethyleneamine means a compound in which nitrogen in ethyleneamine is alkylated, and N-methylethylenediamine, N, N'-dimethylethylenediamine in which nitrogen is methylated. , N, N-dimethylethylenediamine, N, N, N
'-Trimethylethylenediamine, N, N, N', N '
-Tetramethylethylenediamine, nitrogen-ethylated N-ethylethylenediamine, N, N'-diethylethylenediamine, N, N-diethylethylenediamine,
N, N, N'-triethylethylenediamine, N, N,
N ', N'-tetraethyl ethylene diamine etc. are illustrated. The pyrazines mean a pyrazine and a compound having a pyrazine ring, and pyrazine and alkylated pyrazines such as methylpyrazine, dimethylpyrazine, ethylpyrazine and diethylpyrazine are exemplified.

In the method of the present invention, the extraction method is not particularly limited, and any of a batch type, a semi-batch type and a continuous type may be used. As the extraction device, a mixer-settler extractor or a countercurrent differential type extraction is used. There are towers, non-stirred plate extractors, stirred plate extractors, centrifugal extractors, etc. Whichever is used, there is no problem.

[0019]

INDUSTRIAL APPLICABILITY The present invention provides a method for purifying ethyleneamines containing N-alkylated ethyleneamines and / or pyrazines and is industrially very useful.

[0020]

EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Example 1 0.29% by weight of N-ethylethylenediamine and 0.18% by weight of ethylpyrazine relative to ethylenediamine,
0.66 g containing 0.09% by weight of dimethylpyrazine
5.5 g of water was added to the ethylenediamine. This one
Extraction was carried out once with 0 g of methyl acetate at room temperature. The water phase and the oil phase were separated and the water phase was analyzed by gas chromatography. As a result, 0.12% by weight of N-ethylethylenediamine and 0.02% of ethylpyrazine relative to ethylenediamine.
4% by weight and dimethylpyrazine were 0.03% by weight.

Example 2 Example 2 was repeated except that isoamyl alcohol was used instead of methyl acetate. As a result of analyzing the aqueous phase by gas chromatography, N was compared with ethylenediamine.
-Ethylethylenediamine 0.07% by weight, ethylpyrazine 0.02% by weight, dimethylpyrazine 0.00
It became weight%.

Example 3 20 g of water was added to 0.34 g of ethylenediamine, 0.29 g of N-methylethylenediamine and 0.31 g of N-ethylethylenediamine. 1 ml of this was taken, 1 ml of ethyl acetate was added to this, and extraction was performed at room temperature. The water phase and the oil phase were separated and the oil phase was analyzed by gas chromatography. As a result, 0.1% N-methylethylenediamine and 0.6% N were added to the N-alkylated ethyleneamine present in the water phase. -Ethylethylenediamine was extracted in the oil phase, but ethylenediamine was not extracted.

Example 4 20 g of water was added to 0.34 g of ethylenediamine, 0.29 g of N-methylethylenediamine and 0.31 g of N-ethylethylenediamine. 1 ml of this was taken, 1 ml of dichloromethane was added to this, and extraction was performed at room temperature. The water phase and the oil phase were separated, and the oil phase was analyzed by gas chromatography. As a result, 0.6% of N-methylethylenediamine and 2.1% of N were added to the N-alkylated ethyleneamine present in the water phase. -Ethylethylenediamine was extracted in the oil phase, but ethylenediamine was not extracted.

Example 5 0.2973 g ethylenediamine, 0.2919 g N-methylethylenediamine and 0.2923 g N-
20 g of water was added to ethylethylenediamine. That is, both N-methylethylenediamine and N-ethylethylenediamine were prepared as 98% by weight aqueous solutions with respect to ethylenediamine. 1 ml of this was taken, 1 ml of isoamyl alcohol was added thereto, and extraction was carried out at room temperature. The aqueous phase and the oil phase were separated, and the aqueous phase was analyzed by gas chromatography. As a result, N-methylethylenediamine was reduced to 76% by weight with respect to ethylenediamine and N-ethylethylenediamine was reduced to 57% by weight with respect to ethylenediamine. ..

Example 6 1 ml of the aqueous solution of ethylenediamine, N-methylethylenediamine and N-ethylethylenediamine prepared in Example 5 was taken, and 1 ml of cyclohexanol was added thereto, and extraction was carried out at room temperature. As a result of separating the aqueous phase and the oil phase and analyzing the aqueous phase by gas chromatography, N-methylethylenediamine was reduced to 86% by weight with respect to ethylenediamine, and N-ethylethylenediamine was reduced to 72% by weight with respect to ethylenediamine. ..

Example 7 1 ml of the ethylenediamine, N-methylethylenediamine, N-ethylethylenediamine aqueous solution prepared in Example 5 was taken, 1 ml of benzyl alcohol was added thereto, and extraction was carried out at room temperature. The water phase and the oil phase were separated, and the water phase was analyzed by gas chromatography. As a result, N-methylethylenediamine was reduced to 54% by weight with respect to ethylenediamine and N-ethylethylenediamine was reduced to 45% by weight with respect to ethylenediamine. ..

Example 8 1 ml of the ethylenediamine, N-methylethylenediamine, N-ethylethylenediamine aqueous solution prepared in Example 5 was taken, and 1 ml of n-butanol was added thereto, and extraction was carried out at room temperature. The water phase and the oil phase were separated, and the water phase was analyzed by gas chromatography. As a result, N-methylethylenediamine was reduced to 66% by weight with respect to ethylenediamine and N-ethylethylenediamine was reduced to 42% by weight with respect to ethylenediamine. ..

Claims (4)

[Claims] 1. A method for purifying ethyleneamine containing N-alkylated ethyleneamine and / or pyrazines, which comprises extracting an aqueous solution of ethyleneamine with an organic solvent. 2. The purification method according to claim 1, wherein the organic solvent is an ester and / or a halogenoalkane. 3. The purification method according to claim 1, wherein the organic solvent is an alcohol. 4. The purification method according to claim 1, wherein the ethyleneamine is ethylenediamine.