JP5080801B2 - Method for producing N-alkylaminopropionic acid ester and N-alkylaminopropionic acid salt - Google Patents

Description

  The present invention relates to an N-alkylaminopropionate (hereinafter referred to as “N-alkylaminopropionate”) that can be used to prepare a cleaning composition for human bodies such as for skin and hair, and a cleaning composition for hard surfaces such as kitchen and bathroom. The present invention also relates to a method for producing "LAP salt". The present invention also relates to a method for producing an N-alkylaminopropionic acid ester (hereinafter sometimes referred to as “LAP ester”) which is a precursor of the salt.

N-Alkylaminopropionate has low irritation to the skin, so there is a possibility that it will come into contact with the human body, such as a detergent composition that directly contacts the human body, such as skin and hair, and the kitchen, bathroom, clothing, etc. Often used in cleaning compositions.
Conventionally, N-alkylaminopropionate has been produced by hydrolyzing an N-alkylaminopropionic acid ester in the presence of an alkaline aqueous solution (Patent Document 1, etc.). At this time, it is necessary to dilute the salt with water so as to be 3 to 5 times that of the ester, and the volume of the salt increases about 3 to 5 times compared to the volume of the ester. Industrially, a small reaction vessel is used to produce the ester, a large reaction vessel is used to produce the salt, and the ester is prepared and placed in a drum, container, or tank. It is necessary to store temporarily and produce the salt as required. Inevitably, a period for maintaining the ester state after the ester is obtained until the hydrolysis reaction is performed occurs. If the LAP ester is produced in a large reaction vessel used to produce the LAP salt, it is considered that the hydrolysis reaction can be continued without maintaining the ester state, but the LAP ester that can be produced per reaction vessel Since the amount is reduced, the production cost of the LAP ester is increased. Further, since the reaction vessel used for producing the LAP ester is used under reduced pressure, if the capacity is increased, the cost of the reaction vessel increases, which is not economical. On the other hand, the factory operation may be stopped at night or at the end of the year, and in this case as well, the LAP ester will be maintained.
However, if the LAP ester is maintained as it is, particularly when stored for a long time in an environment such as outdoors, the resulting N-alkylaminopropionate is turbid and precipitates, resulting in a problem. Further, in the case of N-laurylaminopropionic acid ethyl ester, since its freezing point is about 12 ° C., it solidifies during storage in winter, so it was necessary to store it warm or to melt it by heating at the time of use. . However, there is a problem that when the warmed and stored one is returned to room temperature and used, the resulting N-alkylaminopropionate is turbid and precipitates are generated.

JP 2000-16975 A

Therefore, an object of the present invention is to improve the low temperature stability of N-alkylaminopropionate.
The present inventors have clarified that the cause of lowering the low-temperature stability of N-alkylaminopropionates is the alkylaminopropionic acid amide produced as a by-product in the production of LAP ester, and by-products when left for a certain period of time. It was found that the amount of alkylaminopropionic acid amide increases. Therefore, this invention also makes it a subject to reduce the quantity of the alkylamino propionic acid amide byproduced when manufacturing LAP ester.

As described above, the present invention has been made by elucidating the cause of lowering the low-temperature stability of N-alkylaminopropionates. As a result of further research based on the knowledge clarified by the present inventors, a specific range of the amount of water contained in the LAP ester corresponding to the precursor of the LAP salt and the amount of the aliphatic primary amine as the raw material of the LAP ester As a result, it was found that the amount of by-products produced can be reduced in a synergistic manner, and the present invention has been completed. That is, the present invention is a method for producing an N-alkylaminopropionic acid ester from an aliphatic primary amine and an acrylic acid ester,
(A) reacting an aliphatic primary amine and an acrylate ester to produce a reaction product containing an N-alkylaminopropionic acid ester;
(B) adding water to the reaction product obtained in the above (a) and then reducing the pressure to distill off the water contained in the reaction product to obtain an N-alkylaminopropionic acid ester; ,
Including
The water content of the N-alkylaminopropionic acid ester obtained in the step (b) is 0.5% by mass or less based on the mass of the ester, and the aliphatic primary amine content is based on the mass of the ester. The production method of an N-alkylaminopropionic acid ester is characterized by adjusting to 0.8% by mass or less.

  The present invention is also capable of generating turbidity and precipitates even when the N-alkylaminopropionate is stored at a low temperature for a long period of time by hydrolysis in an alkaline aqueous solution using the LAP ester obtained by the above production method as a raw material. The present invention has been completed by finding that it can be suppressed. That is, this invention also provides the manufacturing method of N-alkylamino propionate characterized by hydrolyzing the LAP ester obtained by the said manufacturing method in aqueous alkali solution.

  ADVANTAGE OF THE INVENTION According to this invention, the quantity of the alkylamino propionic acid amide byproduced in LAP ester manufacture can be suppressed synergistically. According to the present invention, the turbidity of N-alkylaminopropionate and the generation of precipitates can be suppressed even when stored at a low temperature for a long period of time.

Step (a)
The aliphatic primary amine that can be used in the present invention is represented by the following formula (I).
R ¹ NH ₂ (I)
In the formula, R ¹ represents a saturated or unsaturated linear or branched hydrocarbon group having 6 to 24 carbon atoms, preferably 10 to 22 carbon atoms. The hydrocarbon group may be substituted, and examples of the substituent include a hydroxyl group and a halogeno group. Examples of R ¹ include a hydrocarbon group derived from capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, oleic acid, behenic acid, erucic acid, coconut fatty acid, and beef tallow fatty acid.
A commercial item may be used as an aliphatic primary amine, and it can also manufacture by a well-known manufacturing method from a corresponding fatty acid or alcohol. Examples of commercially available products include those available from Lion Akzo Co., Ltd. under the trade name Armin 12D.
The acrylic ester that can be used in the present invention is composed of acrylic acid and a linear or branched alcohol having 1 to 4 carbon atoms. As the alcohol constituting the acrylate ester, methanol, ethanol, isopropanol, and n-butanol are preferable, and methanol and ethanol are most preferable.

  In this step, it is preferable to use a lower alcohol and water as a reaction solvent for the aliphatic primary amine and the acrylate ester. Here, the lower alcohol refers to a linear or branched alcohol having 1 to 4 carbon atoms, and specifically, methanol, ethanol, isopropanol, n-butanol, iso-butanol and the like can be used. Among these, methanol, ethanol, and isopropanol are preferable, methanol and ethanol are more preferable, and ethanol is most preferable. By using a lower alcohol or water, the reaction between the aliphatic primary amine and the acrylic ester can be promoted, and the amount of primary amine can be reduced quickly.

  In the step (a), the lower alcohol or water and the aliphatic primary amine are used in a mass ratio of 0.05 to 1.0, and the ethyl acrylate and the aliphatic primary amine are used in a molar ratio of 1.1 to 2.0. , It is preferable to react at a temperature of 50 to 90 ° C. for 4 hours or more. By adopting such raw material ratio, reaction temperature and reaction time, the amount of the aliphatic primary amine contained in the obtained LAP ester should be 0.8% by mass or less based on the mass of the LAP ester. Can do.

In the step (a), an aliphatic primary amine and an acrylate ester are reacted. When the hydrocarbon group of the aliphatic primary amine has 12 or more carbon atoms, it is solid at room temperature. The primary amine may be heated in a lower alcohol or water at, for example, 40 to 80 ° C., stirred for a predetermined time to be in a liquid state, and then reacted by adding an acrylate ester. The order in which the aliphatic primary amine and the lower alcohol or water are charged into the reaction vessel is not particularly limited. Examples of the reaction vessel that can be used include an apparatus equipped with a stirring blade and an apparatus equipped with a mixing device such as a mixing pump in an external circulation system. The stirring speed varies depending on the capacity of the stirring device, but is usually 30 to 800 rpm.
The acrylic ester is preferably added gradually from the viewpoint of suppressing a rapid temperature rise due to heat generation. For example, if the acrylic ester is about 250 g, it is preferably added dropwise over 1 hour. The reaction is preferably carried out at normal temperature or under pressure at a temperature of usually 100 ° C. or lower, preferably 50 to 90 ° C. If it is higher than 100 ° C., the odor and hue of the N-alkylaminopropionate may be deteriorated.
At the above temperature, aging is usually performed for 3 to 12 hours, preferably 4 to 8 hours, whereby a reaction product containing the LAP ester is obtained. By aging in such a time, unreacted primary amine and acrylic ester can be reduced. The presence of LAP ester in the reaction product can be confirmed by gas chromatography analysis.

Step (b)
Water is added to the reaction product obtained in the above (a). Prior to this, by gradually reducing the pressure while maintaining the aging temperature, for example, over 0.1 to 2 hours, 6. By reducing the pressure to 7 kPa or less, it is preferable to distill off the unreacted acrylic acid ester and the lower alcohol or water as the reaction solvent contained in the reaction product. By distilling off the acrylic ester and the lower alcohol or water, water can be added and the acrylic ester can be efficiently removed in the subsequent step. If the acrylic ester is removed before adding water, the acrylic ester can be removed with a smaller amount of water than removing the acrylic ester after adding water.
After distilling off the acrylic ester and lower alcohol or water, it is preferable to maintain the temperature and pressure for a predetermined time, for example, 0.1 to 5 hours, before adding water. Thereby, the amount of unreacted acrylic ester remaining can be sufficiently reduced.
When the pressure is reduced after obtaining the reaction product, the pressure is returned to normal pressure before adding water. When returning to normal pressure, it is usually performed over 0.02 to 30 minutes.

The amount of water to be added is preferably 1 to 200% by mass, more preferably 10 to 50% by mass, based on the mass of the reaction product. By adding water and reducing the pressure, the odor of the LAP salt can be improved except for unreacted acrylic ester and lower alcohol contained in the reaction product. When the amount of water is within the above range, the amount of residual acrylic ester is reduced, and a LAP salt having a good odor can be produced. It is preferable to reduce the pressure to 6.7 kPa or less over 0.05 to 2 hours by gradually reducing the pressure after adding water. By slowly reducing the pressure, temperature drop due to entrainment of droplets or latent heat of evaporation can be suppressed. By setting the pressure to 6.7 kPa or less, water can be reduced more quickly and efficiently. After the pressure is set to 6.7 kPa or less, it is preferably maintained for 0.5 to 5 hours. Thereby, the residual water content can be sufficiently reduced. Further, the above-described addition of water → depressurization operation may be repeated. Thereby, the amount of residual acrylic acid ester can be reduced with a small amount of water. Instead of the decompression operation, water can also be blown by circulating an inert gas such as nitrogen or air in the system.
According to the knowledge obtained by the present inventors, even if moisture coexists at the time of storing the LAP ester, it is obtained in the step (b) even though the moisture hardly affects the properties of the LAP ester. The water content of the LAP ester is adjusted to 0.5% by mass or less based on the mass of the LAP ester, and the amount of the aliphatic primary amine contained in the LAP ester is adjusted based on the mass of the LAP ester. Surprisingly, it was found that the amount of by-produced alkylaminopropionic amide can be reduced to 0.8% by mass or less based on the mass of the LAP ester when adjusted to 0.8% by mass or less. It was. In step (b), the water content is maintained at a temperature of 50 to 100 ° C. at a pressure of 6.7 kPa or less for 0.5 hour or more, whereby the amount of water contained in the reaction product is reduced. It is preferable to distill off.
The LAP ester thus obtained is colorless and transparent not only immediately after production but also after storage under heating, and there are no precipitates that can be observed with the naked eye.

  The amount of water contained in the LAP ester can be measured using a Karl Fischer moisture meter. The amount of the remaining aliphatic primary amine and the by-produced alkylaminopropionic acid amide can be measured using, for example, gas chromatography. The measurement apparatus and measurement conditions will be described in detail in the column of the examples.

When the LAP ester thus obtained is used as a raw material and hydrolyzed in an alkaline aqueous solution, an N-alkylaminopropionate having improved low-temperature stability can be produced.
Examples of the alkali that can be used to prepare the alkaline aqueous solution include sodium hydroxide and potassium hydroxide. The concentration of the alkaline aqueous solution is usually 5 to 48% by mass.
In the hydrolysis, water is added to the LAP ester and the temperature is usually raised to 50 to 100 ° C., preferably 60 to 90 ° C. with stirring, and an alkaline aqueous solution is dropped over 0.5 to 2 hours. It can be carried out by aging for 0.5 to 7 hours at ° C. The amount of water to be added is preferably 1 to 5 times the mass of the LAP ester.

  The N-alkylaminopropionate obtained by the production method of the present invention can be used for a wide range of applications as a surfactant excellent in low-temperature stability because it does not show turbidity or precipitate even after storage at low temperatures. Examples of the use of the surfactant obtained by the production method of the present invention include a cleaning composition for human bodies such as for skin and hair, a cleaning composition for hard surfaces such as for kitchens and bathrooms, and cleaning for clothing. Agent composition. In order to prepare these detergent compositions, alcoholic hydrotropes such as lower alcohols and polyalkylene glycols; hydrotropes such as toluenesulfonic acid, xylenesulfonic acid, cumenesulfonic acid, benzoic acid, salicylic acid, and antibacterial agents An agent; a chelating agent such as citric acid, malic acid, and EDTA; a pigment; a fragrance; a viscosity modifier, and the like can be appropriately mixed. Other surfactants can also be used in combination, for example, alkyl sulfate ester salt, alkyl ethoxy sulfate ester salt, α-sulfo fatty acid ester salt, alkylbenzene sulfonate, soap, alkyl ether carboxylate, alkyl sulfosuccinate, Anionic surfactants such as alkyl phosphate ester salts, amino acid derivatives such as alkyl alaninate and alkyl taurate; polyoxyethylene alkyl ether, polyoxyethylene alkyl ester, fatty acid alkanolamide, alkyl polyglucoside, short chain alkyl glucoside length Nonionic surfactants such as chain fatty acid esters, alkylmethylglucamides, sucrose fatty acid esters; alkylamine oxides, alkylcarbobetaines, alkylamidoalkylcarbobetaines, alkylsulfones Tyne, alkyl hydroxy sulfobetaine, an amphoteric surfactant such as alkyl imidazolines or its derivatives can be used. Among these surfactants, anionic surfactants are particularly preferable in terms of high detergency and foam performance. The blending ratio of these surfactants is preferably 10 to 1000 parts by weight with respect to 100 parts by weight of the N-alkylaminopropionate.

A production example of LAP ester is shown below.
[Example 1]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 83.0 g, while heating and stirring at 55 ° C., 265.0 g (2.7 mol) of ethyl acrylate (manufactured by Mitsubishi Chemical) was dropped from the dropping funnel over 1 hour, and then maintained at 70 ° C. Aged for 5 hours.
(B) After the addition reaction, the pressure was gradually reduced at 70 ° C., and the remaining acrylic acid ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, and the pressure was gradually reduced again at 65 ° C., maintained at 2.0 kPa (15 mmHg) for 1 hour to distill off the water, and then returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 0.20%, the water content was 0.07%, the amide was 0.01%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 0.12%. The N-laurylaminopropionic acid ethyl ester after storage was colorless and transparent even at room temperature, and no precipitation was observed.

[Example 2]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 41.0 g, while stirring and heating at 55 ° C., 242.9 g (2.4 mol) of ethyl acrylate (manufactured by Mitsubishi Chemical) was dropped from the dropping funnel over 1 hour, and then maintained at 65 ° C. The mixture was aged for 4.5 hours.
(B) After the addition reaction, the pressure was gradually reduced at 65 ° C., and the remaining acrylic acid ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, and the pressure was gradually reduced again at 65 ° C., maintained at 2.0 kPa (15 mmHg) for 1 hour to distill off the water, and then returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 0.70%, the water content was 0.06%, the amide was 0.01%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 0.28%. The N-laurylaminopropionic acid ethyl ester after storage was colorless and transparent even at room temperature, and no precipitation was observed.

[Example 3]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 62.0 g, while stirring and heating at 55 ° C., 242.9 g (2.7 mol) of ethyl acrylate (manufactured by Mitsubishi Chemical) was dropped from the dropping funnel over 1 hour, and then maintained at 70 ° C. Aged for 5 hours.
(B) After the addition reaction, the pressure was gradually reduced at 70 ° C., and the remaining acrylic acid ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, and the pressure was gradually reduced again at 70 ° C., and maintained at 4.0 kPa (30 mmHg) for 1 hour to distill off the water. Then, the pressure was returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 0.40%, the water content was 0.28%, the amide was 0.02%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 0.36%. The N-laurylaminopropionic acid ethyl ester after storage was colorless and transparent even at room temperature, and no precipitation was observed.

[Example 4]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 41.0 g, 253.9 g (2.5 mol) of ethyl acrylate (Mitsubishi Chemical) was added dropwise over 1 hour while stirring at 55 ° C. over 1 hour, and then maintained at 65 ° C. The mixture was aged for 3.5 hours.
(B) After the addition reaction, the pressure was gradually reduced at 65 ° C., and the remaining acrylic acid ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, the pressure was gradually reduced again at 65 ° C., maintained at 6.7 kPa (50 mmHg) for 1 hour, water was distilled off, the pressure was returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 0.80%, the water content was 0.50%, the amide was 0.02%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 0.81%. The N-laurylaminopropionic acid ethyl ester after storage was colorless and transparent even at room temperature, and no precipitation was observed.

[Comparative Example 1]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 41.0 g, while stirring and heating at 55 ° C., 242.9 g (2.4 mol) of ethyl acrylate (manufactured by Mitsubishi Chemical) was dropped from the dropping funnel over 1 hour, and then maintained at 60 ° C. The mixture was aged for 4.5 hours.
(B) After the addition reaction, the pressure was gradually reduced at 60 ° C., and the remaining acrylic ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, and the pressure was gradually reduced again at 60 ° C., maintained at 8.0 kPa (60 mmHg) for 1 hour to distill off the water, and then returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 0.70%, the water content was 0.61%, the amide was 0.02%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 0.97%. The N-laurylaminopropionic acid ethyl ester after storage was transparent even at room temperature and no precipitation was observed.

[Comparative Example 2]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 32.8 g, while stirring and heating at 55 ° C., 242.9 g (2.4 mol) of ethyl acrylate (manufactured by Mitsubishi Chemical) was dropped from the dropping funnel over 1 hour, and then maintained at 60 ° C. The mixture was aged for 7 hours.
(B) After the addition reaction, the pressure was gradually reduced at 60 ° C., and the remaining acrylic ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, and the pressure was gradually reduced again at 60 ° C., maintained at 6.7 kPa (50 mmHg) for 1 hour to distill off the water, then returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 1.10%, the water content was 0.50%, the amide was 0.02%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 0.95%. The N-laurylaminopropionic acid ethyl ester after storage had a white precipitate at room temperature.

[Comparative Example 3]
(A) In a 1 liter four-necked flask (with a stirrer), 410.0 g (2.2 mol) of laurylamine (“Armin 12D” manufactured by Lion Akzo Co., Ltd.), ethanol (manufactured by Kanto Chemical Co., Inc.) After charging 20.5 g, 253.9 g (2.5 mol) of ethyl acrylate (Mitsubishi Chemical) was added dropwise over 1 hour while stirring at 55 ° C., and then maintained at 60 ° C. The mixture was aged for 9 hours.
(B) After the addition reaction, the pressure was gradually reduced at 60 ° C., and the remaining acrylic ester and ethanol were distilled off. After maintaining at 1.7 kPa (20 mmHg) for 1 hour, the pressure was returned to normal pressure. 41.0 g of water was added, and the pressure was gradually reduced again at 60 ° C., maintained at 13.3 kPa (100 mmHg) for 1 hour to distill off the water, and then returned to normal pressure, and N-laurylaminopropionic acid ethyl ester was added. Obtained.
The residual amine was 1.30%, the water content was 0.81%, the amide was 0.03%, the appearance of the liquid was colorless and transparent, and no precipitate was observed.
The obtained N-laurylaminopropionic acid ethyl ester was stored at 40 ° C. for 2 weeks. When the amount of amide after storage was measured, it increased to 1.80%. The N-laurylaminopropionic acid ethyl ester after storage had a white precipitate at room temperature.

In addition, the water content in the N-alkylaminopropionic acid ethyl ester obtained in Examples 1 to 4 and Comparative Examples 1 to 3, the amount of residual laurylamine and the by-produced alkylaminopropionic acid amide were determined by the following method. And under the same conditions. The results are summarized in Table 1.
<Analysis method>
(1) Moisture Measured with a Karl Fischer moisture meter AQUACOUNTER AQV-7 (Hiranuma Seisakusho).
(2) Amine and amide Measured by gas chromatography.
GC conditions GC device: HP5890 (Agilent)
Column: DB-17 (50% Phenyl 50% Methyl Polysiloxane), 0.25mm × 30m, df 0.25mm
Column temperature: 50 ° C → 280 ° C (5 ° C / min) → 20min
Inj. Temperature: 200 ℃
Det. Temperature: 280 ℃
Detector: FID
Injection volume: 1μL
Sample concentration: 1% ethanol solution Chromatographic peak: amine 18.7 minutes, amide 57 minutes (3) Appearance evaluation After standing at room temperature for 1 day, visual evaluation was performed. The results are indicated by ○ ×. The meaning of each symbol is as follows.
○: colorless and transparent, no precipitate was observed ×: white precipitate was observed

[Example 5]
To a 1 L four-necked flask (with a stirrer) was added 200.0 g of N-laurylaminopropionic acid ethyl ester stored in Example 1 at 40 ° C. for 2 weeks and 388.5 g of water, and the temperature was raised to 70 ° C. with stirring. Warm up. 48% NaOH aqueous solution (diluted to 48% by diluting sodium hydroxide manufactured by Kanto Chemical Co., Ltd. with water) was added dropwise over 1 hour, then aged at 75 ° C. for 2 hours, and sodium N-laurylaminopropionate Got.
[Example 6]
To a 1 L four-necked flask (with a stirrer) was added 100.0 g of N-laurylaminopropionic acid ethyl ester and 382.6 g of water stored in Example 2 at 40 ° C. for 2 weeks, and the temperature was raised to 70 ° C. with stirring. Warm up. 58.7 g of 25% NaOH aqueous solution (diluted to 25% with sodium hydroxide manufactured by Kanto Chemical Co., Ltd.) was added dropwise over 1 hour, then aged at 75 ° C. for 2 hours, and sodium N-laurylaminopropionate. Got.

[Example 7]
The reaction was carried out in the same manner as in Example 6 except that the product stored at 40 ° C. for 2 weeks in Example 3 was used to obtain sodium N-laurylaminopropionate.
[Example 8]
The reaction was conducted in the same manner as in Example 6 except that the 40 ° C. 2-week preserved product of Example 4 was used to obtain sodium N-laurylaminopropionate.

[Comparative Example 4]
The reaction was conducted in the same manner as in Example 5 except that the 40 ° C. 2-week preserved product of Comparative Example 1 was used to obtain sodium N-laurylaminopropionate.
[Comparative Example 5]
The reaction was conducted in the same manner as in Example 6 except that the 40 ° C., 2 W preserved product of Comparative Example 2 was used to obtain sodium N-laurylaminopropionate.
[Comparative Example 6]
The reaction was conducted in the same manner as in Example 6 except that the 40 ° C. 2 W preserved product of Comparative Example 3 was used to obtain sodium N-laurylaminopropionate.

(1) External appearance evaluation method of laurylaminopropionic acid Na It evaluated visually. The results are indicated by ○ ×. The meaning of each symbol is as follows.
○: Transparent x: With white precipitate (2) Method for measuring the amount of AI of Na laurylaminopropionate Using a moisture meter PD-600 (manufactured by Kett Scientific Laboratory), the sample amount is 5 g, at 110 ° C. for 60 minutes. It was measured.

Claims (6)

A method for producing an N-alkylaminopropionic acid ester from an aliphatic primary amine and an acrylic acid ester,
The aliphatic primary amine is represented by the following formula (I):
R ¹ NH ₂ (I)
(In the formula, R ¹ represents a saturated or unsaturated linear or branched hydrocarbon group having 6 to 24 carbon atoms. )
The acrylic ester is composed of acrylic acid and a linear or branched alcohol having 1 to 4 carbon atoms ,
(A) reacting an aliphatic primary amine and an acrylate ester to produce a reaction product containing an N-alkylaminopropionic acid ester;
(B) adding water to the reaction product obtained in the above (a) and then reducing the pressure to distill off the water contained in the reaction product to obtain an N-alkylaminopropionic acid ester; ,
Including
In the step (a), an excessive amount of an acrylic ester is used with respect to the aliphatic primary amine, and the reaction between the aliphatic primary amine and the acrylic ester is performed using a lower alcohol or water as a reaction solvent. Done,
The amount of water added in the step (b) is 1 to 200% by mass with respect to the mass of the reaction product .
The water content of the N-alkylaminopropionic acid ester obtained in the step (b) is 0.5% by mass or less based on the mass of the ester, and the aliphatic primary amine content is based on the mass of the ester. And adjusting to 0.8% by mass or less, a method for producing an N-alkylaminopropionic acid ester. In the said (b) process, it maintains for 0.5 to 5 hours under reduced pressure, The manufacturing method of the N-alkylamino propionic acid ester of Claim 1 characterized by the above-mentioned . The said (a) process WHEREIN: An aliphatic primary amine and acrylic acid ester are made to react at the temperature of 50-100 degreeC, and the obtained reaction product is aged at 50-100 degreeC for 3 to 12 hours. A method for producing an N-alkylaminopropionic acid ester according to 1 or 2 . In the step (a), the lower alcohol or water and the aliphatic primary amine are used in a mass ratio of 0.05 to 1.0, and the ethyl acrylate and the aliphatic primary amine are used in a molar ratio of 1.1 to 2.0. The method for producing an N-alkylaminopropionic acid ester according to any one of claims 1 to 3 , wherein the reaction is performed at a temperature of 50 to 90 ° C for 4 hours or longer. In the step (b), the reaction product is maintained at a pressure of 6.7 kPa or less for 0.5 hours or more at a temperature of 50 to 100 ° C., thereby distilling water contained in the reaction product. The method for producing an N-alkylaminopropionic acid ester according to any one of claims 1 to 4, wherein: A method for producing an N-alkylaminopropionate, comprising hydrolyzing an N-alkylaminopropionic acid ester obtained by the production method according to any one of claims 1 to 5 in an alkaline aqueous solution.