JPH0521098B2 - - Google Patents

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for purifying crude N-alkyl-substituted chloralkylamine hydrochloride obtained by the reaction of N-alkyl-substituted alkanolamine hydrochloride and hydrogen chloride. .

N-alkyl-substituted chloralkylamine hydrochloride (hereinafter abbreviated as chloralkylamine salt) is a pesticide,
It is an extremely useful substance as a modifier for pharmaceuticals, dyes and pigments, and polymeric compounds.
98.0% by weight or more) is required.

(Prior art and its problems) The production of chloralkylamine salts by the reaction of N-alkyl-substituted alkanolamine hydrochloride (hereinafter abbreviated as alkanolamine salt) and hydrogen chloride is known (Japanese Unexamined Patent Publications No. 57-176933, No. 58) −41842 etc.)
However, the reaction solution contains impurities such as hydrochloric acid, unreacted alkanolamine salt, and alkanolamine diether salt in addition to the chloralkylamine salt, and its purity is usually about 97% at most, and further purification is required.

However, since free chloralkylamine is an unstable compound, no effective purification method is known so far. It is an object of the present invention to provide such a purification method.

(Means for Solving the Problems) The present inventors have conducted intensive research to purify the chloralkylamine salt in the reaction solution to a high purity.
(i) The alkanolamine diether salt in the reaction solution is hydrolyzed at 110 to 140°C and decomposed into the raw material alkanolamine salt. (ii) Alkanolamine salts and other impurities are decomposed into an aqueous layer by neutralization and extraction with alkali in the presence of an organic solvent, and chloralkylamine salts are converted into highly pure free N-
It is extracted into the organic solvent layer as an alkyl-substituted chloralkylamine (hereinafter abbreviated as free chloralkylamine). (iii) The present inventors have discovered that free chloralkylamine can be isolated as a highly pure chloralkylamine salt by neutralizing it with an acid such as hydrochloric acid or sulfuric acid, leading to the completion of the present invention.

That is, the present invention provides (1) neutralizing crude N-alkyl-substituted chloralkylamine hydrochloride obtained by the reaction of N-alkyl-substituted alkanolamine hydrochloride and hydrogen chloride with an alkali in the presence of an organic solvent to release free N; - A method for purifying N-alkyl-substituted chloralkylamine hydrochloride, which comprises extracting the alkyl-substituted chloralkylamine into an organic solvent.

(2) The crude N-alkyl-substituted chloralkylamine hydrochloride obtained by the reaction of N-alkyl-substituted alkanolamine hydrochloride and hydrogen chloride is neutralized with an alkali in the presence of an organic solvent to obtain free N-alkyl-substituted chloralkylamine. 1. A method for purifying N-alkyl-substituted chloralkylamine hydrochloride, which comprises extracting it into an organic solvent and then adding an acid thereto to obtain an N-alkyl-substituted chloralkylamine salt.

(3) The purification method according to claim 1, characterized in that impurities in the crude N-alkyl-substituted chloroalkylamine hydrochloride are hydrolyzed with water, followed by neutralization and extraction.

It is known that when free chloralkylamine comes into contact with an alkali even at room temperature, dehalogenation occurs and decomposes into the raw material alkanolamine, and this reaction is also used for quantitative analysis of bound chlorine. It is also known that free chloralkylamines react intermolecularly to produce quaternary ammonium compounds.

However, in the present invention, by neutralizing and extracting the chloralkylamine salt reaction solution with an alkali in the coexistence of an organic solvent, the above-mentioned side reactions are greatly suppressed, and highly pure free chloralkylamine is produced in high yields. What was obtained from this rate was something that could not have been predicted from conventional common sense.

The chloralkylamine salt reaction solution in the present invention is, for example, JP-A-57-176933, JP-A-58-41842.
It is described in the above publication, and is obtained by blowing hydrogen chloride into an alkanolamine salt at 100 to 140°C and reacting while distilling off water as a by-product. It is preferable to add ~30% by weight of water and hydrolyze at 110 to 140°C, then cool to room temperature, and use the alkanolamine diether salt as the alkanolamine salt as the reaction liquid.

The chloralkylamine hydrochloride purified by the present invention has the general formula (In the formula, R ₁ , R ₂ , R ₃ and R ₄ represent a hydrogen atom or a lower alkyl group, and may be the same or different from each other. Also, n means an integer from 2 to 6. In this case, each carbon R ₃ and R ₄ attached to atoms may be the same or different), for example, 2-
Dimethylaminoethyl chloride hydrochloride, 2-diethylaminoethyl chloride hydrochloride, 2-diisopropylaminoethyl chloride hydrochloride, 3-
Dimethylaminopropyl chloride hydrochloride, 2-
Examples include methylaminoethyl chloride hydrochloride, 2-ethylaminoethyl chloride hydrochloride, 2-ethylaminopropyl chloride hydrochloride, and the like.

The organic solvents used in the present invention are hydrocarbons such as n-hexane, cyclohexane, benzene, and toluene, halogenated hydrocarbons such as dichloromethane, chloroform, and dichloroethane, ethers such as diethyl ether, diisopropyl ether, and methyl ethyl ketone and methyl isobutyl. Selected from ketones such as ketones.

The amount of organic solvent used is based on the weight ratio of the reaction solution.
Use 0.5 to 2 times the amount. If the amount of solvent is less than 0.5 times the amount, the yield of the chloralkylamine salt will be greatly reduced, and if the amount is more than 2 times the amount, no improvement in yield will be observed, which is disadvantageous.

In the present invention, the alkali used to neutralize the reaction solution is a hydroxide of an alkali metal or an alkaline earth metal, and is used in the form of a 20 to 25% aqueous solution or slurry.

As for the neutralization method, it is preferable to drop an alkali into the mixture of the reaction solution and the organic solvent.

On the other hand, dropping the reaction solution into an alkaline solution is not preferred because it causes dehalogenation and quaternary ammonium formation, resulting in a low yield.

The neutralization temperature is preferably as low as possible in order to suppress the dehalogenation reaction. However, at low temperatures, the chloralkylamine salt precipitates and becomes sheerbet-like, so neutralization is usually carried out at a temperature of 5 to 30°C, preferably 10 to 20°C.

The pH during neutralization varies depending on the type of chloralkylamine salt, but a range of pH 9 to 11 is suitable. PH
If the pH is less than 9, the yield will be low due to incomplete dissociation of the chloralkylamine salt, and if the pH is higher than 11, dehalogenation and quaternary ammonium formation will occur, resulting in a low yield, which is not preferable.

Further, the neutralization time is desirably within 3 hours in order to suppress the side reactions mentioned above.

Free chloralkylamine extracted into an organic solvent by neutralization is unstable and partially converts into quaternary ammonium during storage, so it can be stored stably by neutralizing it with acid and isolating it as a chloralkylamine salt. become.

The acid is selected from mineral acids such as hydrochloric acid, hydrogen chloride, sulfuric acid, and phosphoric acid, but acid salts are often used industrially.

Free chloralkylamine may be neutralized by adding an acid to an organic solvent solution of free chloralkylamine, or vice versa, by adding an organic solvent solution of free chloralkylamine to an acid. A suitable reaction temperature is 10 to 30°C and a pH of 1 to 2.

When neutralized with hydrogen chloride and sulfuric acid, the chloralkylamine salt precipitates as crystals, so the crystals are
It is made into a product by drying, and the liquid is used repeatedly in the neutralization process. Further, when neutralized using hydrochloric acid water and phosphoric acid, an aqueous chloralkylamine salt solution is obtained, the aqueous layer is isolated as a product by liquid separation, and the organic solvent layer is repeatedly used in the neutralization step.

(Effects of the Invention) According to the purification method of the present invention, loss of unstable free chloralkylamine due to side reactions can be greatly suppressed, and highly pure free chloralkylamine can be obtained.

In addition, the obtained free chloralkylamine can be easily and stably stored as a high-purity chloralkylamine salt by neutralizing it with an acid, and can be used as such salt for many purposes. .

(Examples) Hereinafter, embodiments of the present invention will be specifically illustrated and explained using Examples, but these Examples are merely illustrative, and the technical scope of the present invention is not limited by these in any way. do not have.

In addition, the amine method concentration in the examples is a concentration obtained by measuring total nitrogen by the Kjeldahl method and converting this value into the concentration of the target substance, taking into account the content of impurities.
In addition, the chlorine method concentration is obtained by measuring organically bound chlorine and converting this value into the concentration of the target substance.

The purity of chloralkylamine hydrochloride is calculated by (chlorine method concentration/amine method concentration) x 100.

Example 1 890 g of 2-dimethylamine ethanol and 100 g of water were placed in a two-separable flask equipped with a stirrer, a thermometer, a hydrogen chloride gas inlet tube, and a distillation condenser, and hydrogen chloride was added at 30 to 50°C while stirring and cooling. Gas was blown in at 115 N/Hr for 2 hours to obtain 2-dimethylaminoethanol hydrochloride.

Subsequently, the mixture was heated and heated while blowing hydrogen chloride gas at 28 N/Hr, and the reaction was carried out at 135 to 140°C until almost no by-product water was distilled out (about 36 hours).
650 g of water was added from 138°C, and the mixture was hydrolyzed at 126-131°C for 30 minutes, and then cooled to obtain 2182 g of a reaction liquid. The concentration of the reaction solution by the amine method was 65.73%, the concentration by the chlorine method was 63.62%, and the concentration of 2-dimethylaminoethyl chloride hydrochloride was 96.79%. The reaction yield determined from the chlorine method concentration was 96.4%.

500 g of benzene was added to 500 g of this reaction solution, and a 25% caustic soda solution was added dropwise at 10 to 15° C. while stirring and ice-cooling, and the pH was adjusted to 10.5 in 1 hour.

Immediately after separating the liquids, add 36% hydrochloric acid to the benzene layer.
It was added dropwise at 20-25°C and the pH was adjusted to 1.3. The aqueous layer was separated to obtain 521 g of 2-dimethylaminoethyl chloride hydrochloride solution. As a result of the analysis, the amine method concentration was 59.58%, the chlorine method concentration was 59.11%, and the purity of 2-dimethylaminoethyl chloride hydrochloride was
It was 99.21%. Further, the purification yield from the charged reaction solution was 96.81%.

Example 2 Dichloroethane was added to 500 g of the reaction solution obtained in Example 1.
Add 1000g and cool to 30% at 10-15℃ while stirring and cooling.
A caustic potassium solution was added dropwise to adjust the pH to 10.5 over 1.5 hours. Immediately after standing still and separating the dichloroethane layer for 20~
Bubble hydrogen chloride gas at 50N/Hr at 25℃ to PH1.1
It was adjusted to The produced crystals were filtered and dried to obtain 301 g of white crystals. As a result of the analysis, the amine method concentration of 2-dimethylaminoethyl chloride hydrochloride is
The chlorine method concentration was 99.82%. Further, the purification yield from the charged reaction solution was 94.45%.

Example 3 720 g of 2-diethylaminoethanol and 72 g of water were placed in the same apparatus as in Example 1, and while cooling with stirring, hydrogen chloride gas was added at 134 N/Hr for 2 hours at 30 to 50°C.
After blowing for a while, 2-diethylaminoethanol hydrochloride was obtained. Subsequently, the temperature was raised while blowing hydrogen chloride gas at 34 N/Hr, and the reaction was carried out at 135 to 140°C until almost no by-product water was distilled out (about 32 hours). After adding 300 g of water from 140°C, the mixture was hydrolyzed at 128-133°C and cooled with water to obtain 1404 g of a reaction liquid.

The concentration of the reaction solution by the amine method was 76.03%, the concentration by the chlorine method was 70.45%, and the purity of 2-diethylaminoethyl chloride hydrochloride was 92.66%. The reaction yield determined from the concentration using the hydrochloric acid method was 92.65%.

700 g of methyl isobutyl ketone to 500 g of this reaction solution.
20% calcium hydroxide slurry was added at 10-15℃ while stirring and cooling, and the pH reached 9.8 in 3 hours.
Adjusted to. Immediately, the methyl isobutyl ketone layer was left to stand for liquid separation, and the methyl isobutyl ketone layer was added dropwise to 200 g of 36% hydrochloric acid at 20 to 25°C to adjust the pH to 1.5. The aqueous layer was separated to obtain 552 g of 2-diethylaminoethyl chloride hydrochloride solution.

As a result of the analysis, the amine method concentration was 61.59%, the chlorine method concentration was 61.06%, and the purity of 2-diethylaminoethyl chloride hydrochloride was 99.14%.
Further, the purification yield from the charged reaction solution was 95.69%.

Example 4 800 g of toluene was added to 500 g of the reaction solution obtained in Example 3, and a 25% caustic soda solution was added at 10 to 15° C. while stirring and cooling, and the pH was adjusted to 10.5 in 1 hour.
Separate the aqueous layer and add 193g of 98.2% sulfuric acid to the toluene layer.
It was added dropwise at 10-15°C and the pH was adjusted to 1.1.

The produced crystals were filtered and dried to obtain 456 g of white crystals. As a result of the analysis, the concentration of 2-diethylaminoethyl chloride sulfate using the amine method was 99.62%, and the concentration using the chlorine method was 99.31%. Further, the purification yield from the charged reaction solution was 95.69%.

Comparative Example 1 While stirring and cooling 500 g of the reaction solution obtained in Example 3, a 25% caustic sorter solution was added at 10 to 15°C.
The pH was adjusted to 10.5 in 1 hour. After separation, 36% hydrochloride water was added dropwise to the free chloralkylamine layer at 10 to 15°C to adjust the pH to 1.3 to obtain 466 g of 2-diethylaminoethyl chloride hydrochloride solution.

As a result of the analysis, the concentration using the amine method was 14.3 g, and the concentration using the chlorine method was 50.4%. The purification yield based on the amine method concentration was 17.5%.

This is due to the oligomerization of 2-diethylaminoethyl chloride due to quaternary ammonium formation.
This is presumed to be because it cannot be analyzed using the amine method.

Claims (1)

[Claims] 1. Crude N-alkyl-substituted chloralkylamine hydrochloride obtained by the reaction of N-alkyl-substituted alkanolamine hydrochloride and hydrogen chloride is neutralized with an alkali in the presence of an organic solvent to obtain free N-alkyl A method for purifying N-alkyl-substituted chloralkylamine hydrochloride, which comprises extracting the substituted chloralkylamine into an organic solvent. 2. The crude N-alkyl-substituted chloralkylamine hydrochloride obtained by the reaction of N-alkyl-substituted alkanolamine hydrochloride and hydrogen chloride is neutralized with an alkali in the presence of an organic solvent, and the organic After extraction into a solvent,
1. A method for purifying N-alkyl-substituted chloralkylamine hydrochloride, which comprises adding an acid thereto to obtain an N-alkyl-substituted chloralkylamine salt. 3 After hydrolyzing impurities in the crude N-alkyl-substituted chloralkylamine hydrochloride with water, neutralization,
The purification method according to claim 1 or 2, which comprises extraction.