JPH03188056A - Purification of alkali metal salt of aminoethylsulfonic acid - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention provides an alkali metal salt of chloroethylsulfonic acid,
Efficiently separate and purify alkali metal salts of aminoethylsulfonic acid or alkali metal salts of N-substituted aminoethylsulfonic acids (hereinafter collectively referred to as alkali metal salts of aminoethylsulfonic acids) from the reaction solution with ammonia or N-substituted amines. Regarding how to.

Alkali metal salts of aminoethylsulfonic acid are industrially useful as dyeing aids and materials for agricultural chemical surfactants.

[Prior Art] N-methylethylsulfonic acid alkali metal salt is usually
It is obtained by adding an alkali metal hydroxide to purified N-methylethylsulfonic acid. In German Patent No. 1157234, sulfuric acid was added to the crude reaction solution obtained by the reaction of isethionic acid and methylamine to adjust the hydrogen ion concentration, and then N-methylethylsulfonic acid was purified by crystallization and extracted from the reaction solution. By adding various alkali metal hydroxides to the extracted and then purified N-methylethylsulfonic acid, its alkali metal salts are obtained as purified products.

That is, in order to remove various impurity salts with different chemical and physical properties such as inorganic salts such as mirabilite and unreacted sodium isethionate, and organic sulfonates in the crude reaction solution, N-
It has been purified as methyl ethyl sulfonic acid. This separation and purification method results in the production of additional mirabilite as a by-product and requires the addition of a new step of crystallizing and separating mirabilite. Furthermore, a large amount of the filtration mother liquor after N-methylethylsulfonic acid crystallization must be recycled. That is, it is inevitable that the refining process becomes more complicated and the refining equipment becomes larger.

[Problems to be Solved by the Invention] There is a strong desire for the development of a technology for purifying and separating an alkali metal salt of aminoethyl sulfonic acid purified by a reaction into a product by a simple operation without returning it to a free acid.

For example, the alkali metal salts of chloroethylsulfonic acid used as raw materials usually include alkali metal chlorides and alkali metal sulfates.

It contains inorganic salts and organic salts such as alkali metal sulfonates, and these impurities are brought into the reaction system. In addition, a large amount of alkali metal chloride is produced as a by-product during the reaction of the alkali metal salt of chloroethylsulfonic acid with ammonia or N-substituted amine and during the neutralization process. The challenge has been to find a separation and purification technology that can efficiently remove these inorganic and organic impurities and produce aminoethylsulfonic acid alkali metal salts of excellent quality.

[Means for Solving the Problems] As a result of repeated studies to solve the above problems, the present inventors discovered that the reaction between an alkali metal salt of chloroethylsulfonic acid and ammonia or an N-substituted amine and the reaction after neutralization treatment. By concentrating the reaction solution to a predetermined water concentration, then adding alcohol, and performing a series of separation operations to remove precipitated solids, inorganic salts, organic salts, etc. that coexist with aminoethyl sulfonic acid alkali metal salts are removed. The present inventors have discovered a new fact that impurities can be removed to a high degree, and have completed the present invention.

That is, the present invention comprises: (1) reacting an alkali metal salt of chloroethyl sulfonic acid with ammonia or an N-substituted amine, and then adding an alkali metal hydroxide to perform a neutralization reaction; Concentrate until the water concentration in the reaction solution is 30% by weight or less based on the total weight, and remove the alkali metal salt of aminoethyl sulfonate or alkali N-substituted aminoethyl sulfonate present in the concentrated solution obtained in step (■). Add alcohol in an amount 0.5 times or more the weight of the metal salt, (1) separate and remove the precipitated solid from the slurry liquid obtained in step (2), and (2) remove the alcohol from the separated liquid obtained in step (2). .

The present invention provides a method for purifying alkali metal salts of aminoethylsulfonic acid, which is characterized by comprising the steps (1) to (2) or (2) to (2) above.

The present invention will be explained in detail below.

The present invention is a method for purifying an alkali metal salt of aminoethylsulfonic acid obtained by reacting an alkali metal salt of chloroethylsulfonic acid with ammonia or an N-substituted amine. Alkali metal chloroethyl sulfonate (hereinafter abbreviated as CES) is usually obtained by the reaction of alkali metal sulfite and dichloroethane, and contains alkali metal chloride and alkali metal ethanedisulfonate as by-products. There is. As the raw material of the present invention, purified C
There is no problem in using ES or CES containing a large amount of by-products. Alkali metals include lithium, sodium, and potassium.

Examples include cesium, but sodium and potassium are commonly used industrially. The other raw material, amines, is represented by the chemical formula below.

R2 (R, -H or C1-18 alkyl group, cyclohexyl group, benzyl group, R-H or C alkyl group, cycloh2
1-18 xyl group, benzyl group) That is, specifically ammonia, methylamine.

Ethylamine, propylamine, butylamine.

Examples include octylamine, laurylamine, dimethylamine, diethylamine, dibutylamine, cyclohexylamine, and benzylamine.

The reaction between CES and amines is carried out by a commonly used method. The resulting alkali metal salts of aminoethylsulfonate include sodium aminoethylsulfonate and potassium aminoethylsulfonate.

Sodium N-methylaminosulfonate and its potassium salt, potassium N,N-dimelaminoethylsulfonate,
Examples include sodium N-ethylaminoethylsulfonate, sodium N-butylaminoethylsulfonate, sodium N-cyclohexylaminoethylsulfonate, potassium N-benzylaminoethylsulfonate, and sodium N-octylaminoethylsulfonate. However, the present invention is not limited only to these compounds.

Because hydrochloric acid is generated by the reaction between CES and amines,
After the reaction is completed, neutralization is performed with an alkali metal hydroxide.

Therefore, a considerable amount of alkali metal chloride salt coexists in the reaction solution.

Lithium hydroxide is an alkali metal hydroxide.

Sodium hydroxide, potassium hydroxide, cesium hydroxide, etc. are used, especially sodium hydroxide.

Potassium hydroxide is industrially useful.

Inorganic salts and by-products obtained from the reaction and neutralization
An aqueous solution of an alkali metal aminoethylsulfonic acid salt containing an organic salt is concentrated to obtain a slurry liquid having a water concentration of 30% by weight or less, preferably 26% by weight or less based on the total weight. The concentration method is not particularly limited, but water removal by distillation is industrially advantageous. If the concentration does not reach a water concentration of 30% by weight or less, the amount of impurities coexisting in the final target product will increase, which is disadvantageous in terms of purification.

Particularly preferably, by concentrating to a water concentration of 26% by weight or less, it is advantageous to finally obtain the target product with a low impurity content. The alcohol added to this slurry liquid is an aliphatic alcohol represented by the following chemical formula.

-0H (R-C alkyl group, cyclohexyl group) 2-6 Specifically, ethanol, n-propertool.

Isopropanol, butanol, pentanol.

Examples include hexanol and cyclohexanol.

Medium temo, ethanol, and propatool are useful.

The use of alcohol will vary depending on the type of alkali metal salt of aminoethylsulfonic acid to be purified. Further, an alcohol having compatibility with the alkali metal salt of aminoethylsulfonic acid is appropriately selected. The amount of alcohol added is at least 0.5 times the weight of the aminoethylsulfonic acid metal salt present in the concentrate.

If it is less than 0.5 times the weight, the amount of undesirable impurities coexisting in the final target product will increase, which is not suitable from the viewpoint of purification. It is usually added by 0.5 to 5 times the weight, but there is no problem with adding more than 5 times the weight. However, adding more than 5 times the weight is not advantageous in terms of operability and impurity removal rate.

The addition method may be to add alcohol to the concentrated slurry liquid, or vice versa. Addition time is usually 0
．． A time of 1 to 10 hours is appropriate, and is appropriately determined based on the equipment used and operability. By adding alcohol, impurities such as various inorganic salts and organic salts are precipitated and the system becomes a slurry, so this slurry liquid is separated into solid and liquid. As a separation method, filtration, centrifugation, etc. are applied. As a filtration method, either pressure filtration or vacuum filtration may be applied, and devices such as a filter press and a belt press may be used. Basically, a separation means is selected that can separate solid and liquid from the slurry and preferably reduces the content of mother liquor adhering to the cake after separation as low as possible. The temperature of the slurry subjected to separation is 0 to 90°C, preferably 10 to 70°C, but it varies depending on the type of alkali metal salt of aminoethylsulfonic acid and alcohol to be used. Normally, it is desired to carry out the operation at a temperature below the boiling point of the alcohol used.

The separated liquid recovered in the above separation operation mainly consists of the target alkali metal salts of aminoethylsulfonic acid and alcohols, and the content of impurities such as inorganic salts and organic salts that originally coexisted has been significantly reduced. has been done. Therefore, the recovered liquid itself can be made into a product, and if necessary, alcohols can be further separated and recovered and reused. Any method can be used to recover alcohols, but distillation is the simplest and most advantageous from an industrial perspective. An aqueous solution of the alkali metal salt of aminoethyl sulfonic acid and water after recovering the alcohol may be made into a product, or a solid alkali metal salt of aminoethyl sulfonate from which water has been further removed may be made into a product.

[Effects of the Invention] The method of the present invention is an extremely simple method that removes by-products in a single separation operation while maintaining the sulfonate form without bypassing the organic sulfonate produced by the reaction to the acid form and purifying it. It is a separation and purification method. Since inorganic salts and organic salts as impurities are simultaneously and selectively removed, the number of steps is small and the target product can be recovered with high yield. There is no generation of recycled liquid as seen in acid-type purification, and the number of required equipment is small and can be made more compact. By performing purification under the conditions shown in the present invention, it is possible to obtain high quality aminoethylsulfonic acid alkali metal salts,
The method of the present invention can be said to be an industrially and economically superior separation method.

[Examples] Hereinafter, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 After reacting sodium chloroethylsulfonate and monomethylamine, the free hydrochloric acid was neutralized with caustic soda, resulting in 19.6% sodium N-methylaminoethylsulfonate and sodium N-methyl-bis(2-ethylsulfonate). ) amine 0.
5%, sodium 1,2-ethanedisulfonate 1.3%, Glauber's salt 1.1%.

1210 g of a crude reaction solution consisting of a mixture of 14.5% sodium chloride, 0.6% other organic sodium sulfonate, and 62.4% water was placed in a glass evaporator.

643 g of water was evaporated and concentrated under reduced pressure using an aspirator at a water bath temperature of 90°C.

567 g of the obtained concentrate was heated to 65° C., and 370 g of ethanol was gradually added over 30 minutes while stirring. A slurry consisting of this reaction concentrate and ethanol was stirred at room temperature for 2 hours.
It was left to cool for an hour. The slurry liquid at 25°C is centrifuged (basket diameter 12cm).

The solid-liquid separation operation was performed for 20 minutes. 65 g of water was added to the obtained separated filtrate, and a glass column with a height of 20 cm was attached.
The mixture was placed in a 1-volume glass distillation pot and heated in an oil bath at normal pressure to recover ethanol by distillation. The effluent was 368 g of ethanol and 25 g of water. The residual liquid in the pot after ethanol distillation and recovery was quantified by ion chromatography analysis.

As a result, sodium N-methylaminoethylsulfonate 5
9.4%, N-methyl-bis(2-ethylsulfonic acid sodium)amine 1.4%, 1.2-ethanedisulfonic acid sodium 0.13%, sodium chloride 0.8%, Glauber's salt 0.1
%, other organic sodium sulfonates 0.13%, ethanol 1.0%, and water 38.1%. A significant decrease in the content of impurities such as various organic sodium sulfonates, sodium chloride, and Glauber's salt was confirmed.

Example 2 1210 g of the crude reaction liquid having the same composition as in Example 1 was placed in a third flask made of 21 glass equipped with a 10 cI 11 height glass column equipped with a stirrer, a thermometer insertion tube, and a Liebig condenser. Ta. Oil bath temperature 120-140
Water was removed by distillation at ℃ under normal pressure. 620 g of water was removed from the system to obtain 590 g of slurry. The distillation column part was replaced with a dropping funnel, and 420 g of isopropanol was gradually added dropwise from the dropping funnel over 1 hour. At that time, the temperature of the liquid in the pot was maintained at 60°C. After the contents were cooled to room temperature, solid-liquid separation was performed using the same centrifugation as in Example 1 for 15 minutes. The separated liquid was subjected to ion chromatography analysis and Karl Fischer moisture analysis to determine the composition. As a result, when expressed as a percentage of the composition other than isopropanol, it was found that 60.9% of sodium N-methylaminoethylsulfonate, 1.5% of N-methyl-bis(2-sodium ethylsulfonate)amine, and 1.2% of sodium N-methylaminoethylsulfonate. - Sodium ethanedisulfonate 0.2%, sodium chloride 0.8%, Glauber's salt 0.1%, other organic sodium sulfonates 0.2%, and water 36.2%.

Example 3 In the same 21 glass flask as in Example 2, 21.2% of sodium aminoethylsulfonate, 0.7% of bis(sodium 2-ethylsulfonate) amine, and 1.2% of sodium 1°2-ethanedisulfonate were added. %, sodium chloride 8.1%, mirabilite 1
．． 1111 g of a crude reaction solution having a composition of 1%, 0.2% of other organic sodium sulfonates, and 67.5% of water was added. water 66
3 g was distilled out of the system at an oil bath temperature of 120 to 140° C. under normal pressure for 3 hours.

The distillation column part was replaced with a dropping funnel, and 470 g of 1-propatool was dropped into the concentrated slurry liquid over 15 minutes from the dropping funnel. The operation was carried out under stirring at a slurry liquid temperature of 85°C.
It was carried out in After the dropwise addition was completed, the mixture was allowed to cool for 3 hours and then cooled to room temperature. The slurry was centrifuged for 30 minutes using the same centrifuge as in Example 1. The composition of the separated and recovered liquid was analyzed by ion chromatography and Karl Fischer moisture analysis. As a result, when expressed as a percentage of the composition other than 1-propertool, sodium aminoethylsulfonate was 63.8%, bis(sodium 2-ethylsulfonate) amine was 1.9%, and sodium 1,2-ethanedisulfonate was 0.8%. 3
%, sodium chloride 0.7%, Glauber's salt 0.1%, other organic sulfonic acids 0.2%, and water 33%.

Claims (1)

[Claims] (1) After reacting the alkali metal salt of chloroethylsulfonic acid with ammonia or N-substituted amine, alkali metal hydroxide is added to perform a neutralization reaction, (2) Step ( Concentrate the reaction solution obtained in 1) until the water concentration becomes 30% by weight or less based on the total weight, and then proceed to step (3) (
Adding alcohol in an amount of 0.5 times or more the weight of the alkali metal salt of aminoethylsulfonic acid or the alkali metal salt of N-substituted aminoethylsulfonic acid present in the concentrated solution obtained in 2), Step (4) Separate and remove precipitated solids from the slurry liquid obtained in step (3), and (5) remove alcohols from the separated liquid obtained in step (4). A method for purifying alkali metal salts of aminoethylsulfonic acid, comprising the steps (1) to (4) or (1) to (5) above.