JPH11106369A - Production of alkylamino (meth)acrylate - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject compound excellent in storage stability and capable of being stored without causing the deterioration of purity by subjecting an alkyl (meth)acrylate and an alkylaminoalcohol to a transesterification reaction, distilling out the by-produced alkyl alcohol and subsequently purifying the distillate. SOLUTION: In this method for producing an alkylamino (meth)acrylate of formula III, the characteristics comprise subjecting an alkyl (meth)acrylate of formula I (R<1> is H or methyl; R<2> is a 1-4C alkyl) and an alkylaminoalcohol of formula II (R<3> is H or a 1-8C alkyl; R<4> is a 1-8C alkyl; R<5> is a 1-4C alkylene) to a transesterification reaction, distilling out the by-produced alkyl alcohol as an ezeotropic mixture with the alkyl (meth)acrylate and subsequently purifying the obtained distillate with an ion exchange resin (e.g. an acidic ion exchange resin) preferably in the coexistence of 0.05-100 wt.% of water.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing an alkylamino (meth) acrylate, and more particularly to a method for producing an alkylamino (meth) acrylate by a transesterification reaction between an alkyl (meth) acrylate and an alkylamino alcohol. The present invention relates to a method for recovering an alkyl alcohol by-produced during this reaction, which is suitable for use as an alcohol component for producing an alkyl (meth) acrylate by an esterification reaction and has excellent storage stability. .

In the present invention, alkyl acrylate and alkyl methacrylate are collectively referred to as alkyl (meth) acrylate.

[0003]

2. Description of the Related Art General formula (1):

[0004]

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An alkyl (meth) acrylate represented by the general formula (2):

[0006]

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By transesterification with an alkylamino alcohol represented by the general formula (3):

[0008]

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The production of the alkylamino (meth) acrylate represented by the above formula (the definition of the symbol in the above general formula is as described below) itself is disclosed in Japanese Patent Laid-Open No. 4-950.
No. 54, publicly known. In this method, the transesterification reaction is performed while adjusting the concentration of the alkylamino alcohol in the reaction system to 25 mol% or less.

Japanese Patent Application Laid-Open No. 5-85997 discloses a method for producing dialkylaminoalkyl acrylate using dialkyltin oxide as a catalyst, n-butyl acrylate as an alkyl acrylate, and removing n-butanol as a by-product under reduced pressure. It is described that a transesterification reaction is carried out while distilling off.

Japanese Patent Application Laid-Open No. 3-112949 discloses a method of recovering a catalyst from a reaction solution obtained by a transesterification reaction, wherein the reaction solution is distilled in the absence of oxygen.

Japanese Patent Application Laid-Open No. Hei 6-271517 discloses that a by-product produced when an alkylaminoalkyl ester of (meth) acrylic acid is produced by a transesterification reaction of a (meth) acrylic ester with an alkylamino alcohol is used as a catalyst. Describes a method of decomposing the compound.

JP-A-6-256271 discloses a transesterification reaction between a (meth) acrylic acid ester and an alkylamino alcohol to produce an alkylaminoalkyl ester of (meth) acrylic acid or a by-product remaining. Are described by distillation.

JP-A-54-163517 discloses a process for producing a dialkylaminoalkyl (meth) acrylate by a transesterification reaction between an alkyl ester of (meth) acrylic acid and a dialkylaminoalkanol. A first step of performing the reaction, a second step of distilling off low-boiling unreacted raw materials from the reaction mixture obtained in the first step, and a dialkylaminoalkyl (meth) acrylate concentration of 90% obtained in the second step A method of distilling the above mixture under reduced pressure at a temperature of 60 to 100 ° C. is described.

[0015]

Since the transesterification reaction is an equilibrium reaction, the reaction is carried out while distilling off by-product alkyl alcohol out of the reaction system. Industrially, a distillation column (in the present invention, this is called an "alcohol distillation column") is provided in a reactor, and by-product alkyl alcohol is distilled off from the top of the column as an azeotrope with alkyl (meth) acrylate. doing. Then, the distillate from the alcohol distillation column is further distilled as necessary,
Alkyl alcohol is recovered from the top of the column as an azeotrope with alkyl (meth) acrylate, and bottoms substantially consisting of alkyl (meth) acrylate is recovered from the bottom of the column. Reused for exchange reactions.

Since the alkyl alcohol recovered as described above (hereinafter sometimes referred to as “recovered alkyl alcohol”) contains an alkyl (meth) acrylate, the alkyl (meth) acrylate is usually produced by an esterification reaction. Used as an alcohol component. When the alkyl (meth) acrylate production plant is located on the same or adjacent site as the transesterification reaction plant, the recovered alkyl alcohol is stored in an intermediate tank or the like, if necessary, and then transferred by pipes or other means. Transferred to an alkyl (meth) acrylate manufacturing plant and if both are far away,
After being stored in a storage tank or the like, it may be transported to an alkyl (meth) acrylate production plant by means such as a tank lorry.

However, when the above-mentioned recovered alkyl alcohol is used as an alcohol component for producing an alkyl (meth) acrylate, a strong acidic ion exchange resin generally used as an esterification catalyst for producing an alkyl (meth) acrylate can be used. There is a problem that deterioration is apt to occur, the yield of alkyl (meth) acrylate decreases, and the purity decreases when the recovered alcohol is stored for a certain period of time.

Thus, an object of the present invention is to provide a compound represented by the general formula (3) by a transesterification reaction between an alkyl (meth) acrylate represented by the general formula (1) and an alkylamino alcohol represented by the general formula (2). In the method for producing an alkylamino (meth) acrylate represented by the formula (1), the alkyl alcohol by-produced during this reaction is suitable for use in the production of the alkyl (meth) acrylate, and the purity is reduced during storage. It is an object of the present invention to provide a method of recovering a storage product which is excellent in storage stability without lowering.

[0019]

Means for Solving the Problems The present inventors have used dimethylaminoethanol as an alkylamino alcohol,
In addition, as a result of intensive studies on a transesterification reaction in which methyl acrylate was used as an alkyl (meth) acrylate and methanol was generated as a by-product alkyl alcohol, the following findings were obtained.

(1) In the transesterification reaction, a side reaction in which trimethylamine, methyl dimethylaminopropionate, acetaldehyde and the like are generated has occurred.

(2) Trimethylamine, methyl dimethylaminopropionate and acetaldehyde are distilled from the alcohol distillation column and mixed into the distillate. Further, even if this distillate is supplied to the next distillation column and further distilled, trimethylamine and acetaldehyde and some methyl dimethylaminopropionate are distilled off. Therefore, trimethylamine, methyl dimethylaminopropionate, and acetaldehyde are mixed in the recovered methanol. And among these impurities, especially trimethylamine and methyl dimethylaminopropionate poison the catalyst for producing alkyl (meth) acrylate,
It is thought to degrade its performance.

(3) If trimethylamine or methyl dimethylaminopropionate is mixed in the recovered methanol, it becomes a catalyst for causing a Michael addition reaction between the methanol in the recovered methanol and methyl acrylate. As a result, methoxypropionic acid It is considered that methyl is generated and the purity of the recovered methanol decreases.

As a method for removing a basic nitrogen compound which becomes a catalyst poison of the above-mentioned catalyst for producing an alkyl (meth) acrylate and causes a decrease in the purity of the recovered alkyl alcohol, an acidic aqueous solution is added to neutralize the compound. Although extraction may be considered, since the alkyl alcohol is transferred to the aqueous phase, it is necessary to recover the alkyl alcohol from the aqueous phase again by distillation or the like, so that the operation becomes complicated,
It is not industrially advantageous.

Therefore, the present inventors have further studied and found that the above-mentioned recovered methanol can be efficiently removed by, for example, an acidic ion exchange resin to remove a basic nitrogen compound. The present invention has been completed.

That is, the present invention provides a compound represented by the general formula (1):

[0026]

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Wherein R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 1 to 4 carbon atoms, and an alkyl (meth) acrylate represented by the general formula (2):

[0028]

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(Wherein R ³ is a hydrogen atom or a group having 1 to 1 carbon atoms)
8 is an alkyl group, R ⁴ is an alkyl group having 1 to 8 carbon atoms, and R ⁵ is an alkylene group having 1 to 4 carbon atoms)
By transesterification with an alkylamino alcohol represented by the general formula (3)

[0030]

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In the method for producing an alkylamino (meth) acrylate represented by the formula (wherein each symbol is the same as described above), the alkyl alcohol by-produced during the transesterification reaction is co-existed with the alkyl (meth) acrylate. A process for producing an alkylamino (meth) acrylate, comprising distilling off a boiling mixture and purifying an obtained distillate with an ion exchange resin.

Further, according to the present invention, there is provided a method for producing an alkylamino (meth) acrylate as described above, wherein (1) the reaction solution taken out from the transesterification reactor (A) is supplied to a catalyst recovery unit (E) and heated. Distilling alkylamino (meth) acrylate, alkyl (meth) acrylate and alkylaminoalcohol from the top, (2) alkylamino (meth) acrylate, alkyl (meth) acrylate and alkylamino from catalyst recovery unit (E) The distillate containing the alcohol is supplied to the light-boiling matter separation tower (F) for distillation, and (3) the bottoms from the light-boiling matter separation tower (F) is supplied to the rectification tower (G) for distillation. And removing the product alkylamino (meth) acrylate from the top of the column, and (4) alkyl (meth) from the alcohol distillation column (B).
A method for producing an alkylamino (meth) acrylate, comprising supplying a distillate containing an acrylate and an alkyl alcohol to an ion exchange resin purification tower (D) for purification.

In a preferred embodiment of the present invention, in the above method for producing an alkylamino (meth) acrylate, (1) the reaction liquid taken out of the transesterification reactor (A) is supplied to the catalyst recovery unit (E) and heated. And from the top alkylamino (meth) acrylate, alkyl (meth)
The acrylate and the alkylamino alcohol are distilled off, and (2) the distillate containing the alkylamino (meth) acrylate, alkyl (meth) acrylate and alkylaminoalcohol from the catalyst recovery unit (E) is separated into a light-boiling substance separation column (F ), Distillation is performed, and alkyl (meth) acrylate and alkylamino alcohol are recovered from the top of the column, circulated to the reactor (A), and (3) bottom liquid from the light boiling point separation column (F) Is supplied to the rectification column (G) for distillation,
The product alkylamino (meth) acrylate is taken out from the top of the column, and (4) the bottom product from the rectification column (G) is supplied to the thin-layer distillation column (H) for distillation, and the distillate from the top is removed. The distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the alcohol distillation column (B) is circulated to the light boiling point separation column (F) and fed to the ion exchange resin purification column (D). To purify. In another preferred embodiment of the present invention, in the method for producing an alkylamino (meth) acrylate, (1) the transesterification reactor (A)
The reaction solution taken out from is supplied to the catalyst recovery unit (E) and heated, and the alkylamino (meth) acrylate,
The alkyl (meth) acrylate and alkylamino alcohol are distilled off, and (2) alkylamino (meth) acrylate, alkyl (meth) from the catalyst recovery unit (E)
The distillate containing acrylate and alkylamino alcohol is supplied to the light-boiling point separation column (F) and distilled, and alkyl (meth) acrylate and alkylamino alcohol are recovered from the top and circulated to the reactor (A). And (3)
The bottom product from the light-boiling matter separation column (F) is supplied to the rectification column (G) for distillation, and the product alkylamino (meth) acrylate is taken out from the top of the column. (4) From the rectification column (G) Is fed to a thin-layer distillation column (H) for distillation, a distillate from the top is circulated to a light-boiling matter separation column (F), and (5) an alcohol distillation column (B). The distillate containing the alkyl (meth) acrylate and the alkyl alcohol is supplied to the distillation column (C) and distilled, and (6) the distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the distillation column (C) is distilled. The discharged liquid is supplied to an ion exchange resin purification tower (D) for purification.

[0034]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Representative examples of the alkyl (meth) acrylate of the general formula (1) used in the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, n-propyl (meth) acrylate, and n-propyl (meth) acrylate. -Butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate and n-octyl (meth) acrylate. Of these, methyl (meth) acrylate, ethyl (meth) acrylate and n-butyl (meth) acrylate are preferred.

Representative examples of the alkylamino alcohol of the general formula (2) include dimethylaminoethanol,
Diethylaminoethanol, dipropylaminoethanol, dibutylaminoethanol, dipentylaminoethanol, dihexylaminoethanol, dioctylaminoethanol, methylethylaminoethanol, methylpropylaminoethanol, methylbutylaminoethanol, methylhexylaminoethanol, ethylpropylaminoethanol, ethyl Butylaminoethanol,
Examples include ethylpentylaminoethanol, ethyloctylaminoethanol, propylbutylaminoethanol, dimethylaminopropanol, diethylaminopropanol, dipropylaminopropanol, dibutylaminopropanol, butylpentylaminopropanol and t-butylaminoethanol. Of these, dimethylaminoethanol and diethylaminoethanol are preferred.

As a representative example of the alkylamino (meth) acrylate of the general formula (3) obtained by transesterification of the alkyl (meth) acrylate of the general formula (1) with the alkylamino alcohol of the general formula (2) May include dimethylaminoethyl (meth) acrylate, diethylaminoethyl (meth) acrylate, dimethylaminopropyl (meth) acrylate, dimethylaminobutyl (meth) acrylate and dibutylaminoethyl (meth) acrylate.

The method itself for producing an alkylamino (meth) acrylate of the general formula (3) by transesterification of the (meth) acrylate of the general formula (1) with an alkylamino alcohol of the general formula (2) is as described above. As of,
It is described in JP-A-4-95054. The present invention does not have any feature in the transesterification itself, and the transesterification is described in Japanese Patent Application Laid-Open No. 4-95054.
As described in Japanese Patent Application Laid-Open Publication No. H10-260, the reaction is performed while adjusting the concentration of the alkylamino alcohol in the reaction system to 25 mol% or less, using any catalyst, polymerization inhibitor, etc., and any method, conditions, etc. Can be performed in accordance with

FIG. 1 is a system diagram showing one embodiment of the method of the present invention, and FIG. 2 is a system diagram showing another embodiment.
Hereinafter, the method of the present invention will be described with reference to FIG.

First, in the reactor (A), an alkyl (meth) acrylate of the general formula (1) and a compound of the general formula (2)
Is transesterified with an alkylamino alcohol. Since the transesterification reaction is an equilibrium reaction, an alcohol distillation column (B) is provided in accordance with a conventional method to separate and remove the by-produced alkyl alcohol and proceed with the reaction. Distill as azeotrope with acrylate.

The operating conditions of the alcohol distillation column (B) are not particularly limited. For example, a multi-stage distillation column is used to efficiently distill by-product alkyl alcohol as an azeotrope with alkyl (meth) acrylate. Under suitable conditions, for example, under normal pressure to reduced pressure, at a tower top temperature of 40 to 12
Distillation may be performed at 0 ° C. and a reflux ratio of 0.5 to 15.

The distillate containing alkyl (meth) acrylate and alkyl alcohol obtained from the alcohol distillation column (B) is supplied to the ion exchange resin purification column (D) for purification. Usually, the distillate may be passed through the ion-exchange resin packed bed at normal temperature and normal pressure.

As shown in FIG. 2, it is preferable that the distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the alcohol distillation column (B) is supplied to the distillation column (C) for distillation. That is, the distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the alcohol distillation column (B) is supplied to the distillation column (C) for distillation, and from the top, the alkyl alcohol concentration is increased. And a distillate containing alkyl (meth) acrylate, while a bottoms substantially consisting of alkyl (meth) acrylate is taken out from the bottom of the column, circulated to the reactor (A), and returned to the transesterification reaction. use.
By the distillation in the distillation column (C), the content of the alkyl (meth) acrylate in the distillate containing the alkyl alcohol and the alkyl (meth) acrylate is reduced, and the alcohol component for producing the alkyl (meth) acrylate is reduced. It is suitable for use as.

There are no particular restrictions on the operating conditions of the distillation column (C). For example, a multi-stage distillation column is used to distill the alkyl (meth) acrylate under conditions suitable for recovering a portion of the bottoms as bottoms. do it. Specifically, since it depends on the content of a distillate containing an alkyl (meth) acrylate and an alkyl alcohol, it cannot be specified unconditionally,
Usually, distillation may be performed under normal pressure to reduced pressure at a tower top temperature of 40 to 120 ° C. and a reflux ratio of 0.5 to 15.

The distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the distillation column (C) is the same as the distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the alcohol distillation column (B). Similarly, it is supplied to the ion exchange resin purification tower (D) for purification.

As the ion exchange resin, for example, an acidic ion exchange resin is used. The acidic ion exchange resin is such that the base resin is a phenolic resin, a styrene resin or a (meth) acrylic acid resin, and has any one of a gel type, a porous type, and a macroporous type, and It means those containing at least one ion exchange group selected from sulfonic acid groups, alkylsulfonic acid groups and carboxyl groups. Among these acidic ion exchange resins, a weakly acidic ion exchange resin containing a carboxyl group as an ion exchange group is particularly preferably used.

The reason is that, in the case of a strongly acidic ion exchange resin containing sulfonic acid groups, acetaldehyde contained in the distillate to be purified reacts with the alkyl alcohol due to the action of the sulfonic acid group, for example, the alkyl alcohol This is because, when is methanol, 1,1-dimethoxyethane is easily generated. Since 1,1-dimethoxyethane has a boiling point of 64.5 ° C., for example, close to the boiling point of methyl acrylate of 80 ° C., when the recovered alcohol after purification is used for the production of methyl acrylate, the reaction system is circulated together with methyl acrylate. The problem of accumulation. In contrast, in the case of a weakly acidic ion exchange resin containing a carboxyl group as an ion exchange group,
The basic nitrogen compound can be efficiently removed without changing acetaldehyde to 1,1-dimethoxyethane.

Specific examples of the above weakly acidic ion exchange resins include Duolite C-433, C-464 and C-470.
V, C-436, ES-460, ES-462 (made by Rohm & Haas), Amberlite IRC-75, IRC-
84, IRC-50 (manufactured by Rohm & Haas), Diaion WK-20, WK-10, WK-11 (manufactured by Mitsubishi Chemical Corporation), Revadet CNP (manufactured by Bayer), Dowex CCR-2 (manufactured by Dow) And the like.

Regarding the degree of purification in the ion exchange resin tower (D), the total nitrogen contained in the liquid containing the purified alkyl alcohol and alkyl (meth) acrylate (hereinafter sometimes referred to as “purified alkyl alcohol”) The content should be 0.002% by weight (20 ppm) or less, preferably 0.001% by weight (10 ppm) or less. Here, the total nitrogen content is the total content of nitrogen in the nitrogen-containing compound containing trimethylamine and methyl dimethylaminopropionate as main components as by-products, and is measured by the following method.

Measurement of total nitrogen content Using a trace total nitrogen analyzer TN-05 (manufactured by Mitsubishi Chemical Corporation), the flow rate of oxygen was 600
The measurement was performed by a prescribed method at a temperature of 800 ml / min, an inlet temperature of 800 ° C, and a catalyst phase temperature of 900 ° C.

The purification in the ion exchange resin tower (D) is preferably performed in the presence of water. The water content is based on the weight of the distillate containing alkyl alcohol and alkyl (meth) acrylate introduced into the ion exchange resin tower (D),
The content is 0.05 to 100% by weight, preferably 0.1 to 50% by weight, and more preferably 0.2 to 20% by weight.

When the amount of water coexisting in the distillate is small, there arises a problem that the ion exchange resin is colored and then the purified alkyl alcohol is colored. Further, when a large amount of water coexists, the amount of purification treatment increases, which increases the production cost, and is disadvantageous in storage and transportation.

In order to allow a predetermined amount of water to coexist in the distillate, the water is introduced into, for example, a conduit from the alcohol distillation column (B) or the distillation column (C) to the ion exchange resin column (D). Or may be directly introduced into the ion exchange resin tower (D).

The purified alcohol obtained as described above has a sufficient content of a basic nitrogen compound which poisons the catalyst for producing an alkyl (meth) acrylate and has a low content, so that an alkyl (meth) acrylate is produced. Can be suitably used as an alcohol component. In addition, the reaction between the alkyl alcohol and the alkyl (meth) acrylate is prevented, and a decrease in the purity of the purified alcohol during storage or transportation can be effectively prevented.

The purified alcohol is stored in a tank or the like, if necessary, and then transferred to an alkyl (meth) acrylate production plant to be used as an alcohol component for producing an alkyl (meth) acrylate.

The reaction solution taken out from the reactor (A) is supplied to the catalyst recovery unit (E) and heated, and the alkylamino (meth) acrylate, unreacted alkyl (meth) acrylate and unreacted alkyl Is distilled off, while the catalyst is removed from the bottom and recovered. The catalyst thus recovered can be circulated to the reactor (A) and reused. In addition, since the catalyst performance is reduced when the reaction is repeated, at that time, the catalyst is generally discarded without circulation.

When distilling the above-mentioned alkylamino (meth) acrylate, alkyl (meth) acrylate and alkylamino alcohol, normal pressure or 50 mmH
g under reduced pressure and reactor temperature 50-140 ° C
Is distilled under the conditions of
The fraction containing acrylate is distilled off and then 100 to 5
It is preferable to distill under a condition of mmHg and a temperature in the reactor of 60 to 140 ° C. to distill a fraction mainly containing alkylamino (meth) acrylate. In this case, the first distillate containing alkyl (meth) acrylate is circulated to the reactor (A), and then the alkylamino (meth) acrylate
The fraction containing acrylate is stored in an intermediate tank if necessary, and then supplied to a light-boiling matter separation column (F) for distillation.
Alkyl (meth) acrylate and alkylamino alcohol as light boiling components are distilled off from the top of the column and circulated to the reactor (A). On the other hand, the bottoms containing the alkylamino (meth) acrylate is supplied to the rectification column (G).

The light-boiling matter separation tower (F) is for separating light-boiling substances from the distillate from the catalyst recovery tower (E).
Under reduced pressure of Hg, the top temperature is 60 to 140 ° C., and the reflux ratio is 0.5
Distill under conditions of ~ 30.

The bottoms mainly containing alkylamino (meth) acrylate from the light-boiling matter separation column (F) is supplied to a rectification column (G), where the product is rectified to obtain a product alkylamino (meth) acrylate. From the top of the tower. The operating conditions of the rectification column (G) are not particularly limited, and usually a multi-stage distillation column is used, under reduced pressure of 5 to 150 mmHg, and a top temperature of 30 to 30 mmHg.
Distillation is performed at a temperature of 100 ° C. and a reflux ratio of 0.3 to 10.

Since the alkylamino (meth) acrylate still remains in the bottoms of the rectification column (G), the bottoms are collected by a thin-layer distillation column (H) in order to recover them. And distillate containing alkylamino (meth) acrylate is collected and circulated to the light-boiling matter separation column (F). The bottom liquid from the thin layer distillation column (H) is discarded as waste liquid.

The distillation in the thin-layer distillation column (H) may be performed using a thin-layer still and distillation conditions suitable for distilling the above-mentioned alkylamino (meth) acrylate. For example, distillation may be performed at a temperature in the range of 60 to 140 ° C. under reduced pressure using a vertical thin-layer still.

[0061]

The purified alkyl alcohol obtained by the method of the present invention has a reduced content of a basic nitrogen compound which is a catalyst poison of the catalyst for producing an alkyl (meth) acrylate. It can be suitably used as an alcohol component for the production.

Further, the purified alkyl alcohol obtained by the method of the present invention can prevent side reactions between the alkyl alcohol and the alkyl (meth) acrylate therein, so that it has excellent storage stability and does not cause a decrease in purity. It can be stored stably for a long time.

[0063]

EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. “Parts” means “parts by weight”.

The term “alcohol purification / recovery step” in the Examples means a step including the distillation column (C) and the ion exchange resin purification column (D) of the present invention. > Means a process including the catalyst recovery unit (E), the light-boiling matter separation column (F), the rectification column (G), and the thin-layer distillation column (H) of the present invention.

Each component other than the total nitrogen content was quantified by gas chromatography. Example 1 160.5 dimethylaminoethanol was placed in a 3 L (liter) flask (reactor (A)) equipped with a stirrer, a thermometer and a fractionating tower (alcohol distillation tower (B)).
, 1704.6 parts of methyl acrylate, 16.0 parts of dibutyltin oxide as a catalyst, and 8.5 parts of phenothiazine as a polymerization inhibitor, and the mixture was heated with stirring. After the start of reflux, 641.8 parts of dimethylaminoethanol was added so that the concentration of dimethylaminoethanol in the reaction system did not exceed 10 mol%. The addition time was 4 hours. The methanol produced by the reaction maintains the top temperature of the fractionation tower at 62 to 70 ° C. and the reflux ratio is 0.5 to 5.5.
Methanol by-produced at 0 was distilled off as an azeotrope with methyl acrylate. The reaction was completed in 8 hours, and the reaction mixture was analyzed. As a result, the conversion of dimethylaminoethanol was 95 mol%, and the selectivity to dimethylaminoethyl acrylate was 98 mol%.

<Alcohol Purification / Recovery Step> A distillate containing methanol and methyl acrylate from a fractionation tower (alcohol distillation column (B)) is charged into a distillation device (distillation column (C)), and the temperature at the top of the column is increased under normal pressure. Distillation was carried out at 62 ° C. under a reflux ratio of 1.5, and an azeotropic mixture of methanol and methyl acrylate was taken out from the upper part, and methyl acrylate was taken out from the lower part. The composition of the distillate from above was as follows.

Composition of distillate from distillation apparatus (distillation column (C)) Methanol: 48.5% by weight Methyl acrylate: 51.3% by weight Acetaldehyde: 890 ppm 1,1-Dimethoxyethane: 70 ppm Methyl methoxypropionate: 0.1% by weight Total nitrogen content: 93 ppm Water was added to the distillate from the distillation column (distillation column (C)) in an amount of 0.2%.
% By weight, and a column (ion exchange resin purification tower (D)) filled with 200 ml of a weakly acidic ion exchange resin: Diaion WK-40 (manufactured by Mitsubishi Chemical Corporation) at room temperature.
The solution was passed under normal pressure. The composition of the liquid (purified alcohol) from this ion-exchange resin packed column (ion-exchange resin purification tower (D)) was as follows.

Composition of purified alcohol (early distillation) Methanol: 48.5% by weight Methyl acrylate: 51.3% by weight Acetaldehyde: 890 ppm 1,1-Dimethoxyethane: 70 ppm Methyl methoxypropionate: 0.1% by weight Total nitrogen Content: 3 ppm The ion-exchange resin was not colored even 200 hours after the start of the liquid passing, and the purified alcohol was colorless and transparent.

Next, the purified alcohol was added at 30 ° C. for 10 hours.
After storage for days, analysis revealed that the composition was as follows, with no change.

Composition of purified alcohol (after storage for 10 days) Methanol: 48.5% by weight Methyl acrylate: 51.3% by weight Acetaldehyde: 890 ppm 1,1-Dimethoxyethane: 70 ppm Methyl methoxypropionate: 0.1% by weight Nitrogen content: 3 ppm Comparative Example 1 The distillate from the distiller (distillation column (C)) in Example 1 was analyzed after being stored at 30 ° C. for 10 days, and the composition was as follows. The composition before storage is also shown.

Composition of distillate Methanol: 48.5% by weight Methyl acrylate: 51.3% by weight Acetaldehyde: 890 ppm 1,1-Dimethoxyethane: 70 ppm Methyl methoxypropionate: 0.1% by weight Total nitrogen content: 93 ppm 10 Composition of distillate after storage for one day Methanol: 48.0% by weight Methyl acrylate: 50.1% by weight Acetaldehyde: 890 ppm 1,1-Dimethoxyethane: 70 ppm Methyl methoxypropionate: 1.8% by weight Total nitrogen content: 93 ppm From the above results, it can be seen that when the total nitrogen content is 93 ppm, the concentrations of methanol and methyl acrylate are reduced by storage, and methyl methoxypropionate as an impurity is by-produced.

Example 2 A transesterification reaction was carried out in exactly the same manner as in Example 1.

<Alcohol Purification / Recovery Step> Same as in Example 1.

<Dimethylaminoethyl acrylate purification step> The reaction solution from the flask (reactor (A)) was transferred to a 3 L internal volume flask (catalyst recovery unit (E)) equipped with a stirrer, thermometer and fractionating tower. Put, normal pressure ~ 100mmHg,
Under the conditions of an internal temperature of 75 to 90 ° C., a fraction mainly containing methyl acrylate is distilled off.
100-20 mmHg and 80-110 ° C, respectively
Then, a distillate containing 73% by weight of dimethylaminoethyl acrylate was obtained. A catalyst solution containing dibutyltin oxide and phenothiazine was obtained from the bottom. This catalyst solution was used for the next reaction.

A liquid containing 73% by weight of the above dimethylaminoethyl acrylate was introduced into a fractionator (light boiling point separation column (F)), and distillation was performed under a reduced pressure of 40 mmHg at the top of the column. Methyl acrylate and dimethylaminoethanol were distilled off at an overhead temperature of 50 ° C. and a reflux ratio of 5 to 20. Dimethylaminoethyl acrylate 9 from the bottom
A liquid containing 3% by weight was obtained.

A liquid containing 93% by weight of the above dimethylaminoethyl acrylate was introduced into a fractionator (rectification column (G)), and distillation was performed under a reduced pressure of 25 mmHg at the top of the column. Dimethylaminoethyl acrylate was distilled off at an overhead temperature of 76-79 ° C. A liquid containing 70% by weight of dimethylaminoethyl acrylate was obtained from the bottom.

The above dimethylaminoethyl acrylate 7
The liquid containing 0% by weight was placed in a vertical thin-layer distillation apparatus (thin-layer distillation tower (H)) and distilled under a reduced pressure of 25 mmHg. A liquid containing 50% by weight of dimethylaminoethyl acrylate was distilled off at a temperature of 76 to 79 ° C, and a liquid containing 5% by weight of dimethylaminoethyl acrylate was obtained from the bottom.

The yield of dimethylaminoethyl acrylate obtained as described above was 400.2 g and the purity was 9
It was 9.8% by weight. The yield was 93 mol% based on the charged dimethylaminoethanol.

Example 3 Methanol was purified in the same manner as in Example 1 except that DOWEX-HCR-W2-H type (manufactured by Dow) was used as the ion exchange resin. did. The composition of this purified alcohol was as follows.

Composition of Purified Alcohol (Early Distillation) Methanol: 48.4% by weight Methyl acrylate: 51.3% by weight Acetaldehyde: 6 ppm 1,1-Dimethoxyethane: 1800 ppm Methyl methoxypropionate: 0.1% by weight Total nitrogen Content: 3 ppm The ion-exchange resin was not colored even 200 hours after the start of the liquid passing, and the purified alcohol was colorless and transparent.

Next, the purified alcohol was added at 30 ° C. for 10 hours.
After storage for days, analysis revealed that the composition was as follows, with no change.

Composition of purified alcohol (after storage for 10 days) Methanol: 48.4% by weight Methyl acrylate: 51.3% by weight Acetaldehyde: 6 ppm 1,1-dimethoxyethane: 1800 ppm Methyl methoxypropionate: 0.1% by weight Nitrogen content: 3 ppm

[Brief description of the drawings]

FIG. 1 is a system diagram of one embodiment of the method of the present invention.

FIG. 2 is a system diagram of another embodiment of the method of the present invention.

[Explanation of symbols]

 A Reactor B Alcohol distillation column C Distillation column D Ion exchange resin column E Catalyst recovery unit F Light boiling point separation column G Rectification column H Thin layer distillation column

Claims (7)

[Claims] 1. General formula (1): Wherein R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 1 to 4 carbon atoms, and an alkyl (meth) acrylate represented by the general formula (2): (Wherein, R ³ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁴ is an alkyl group having 1 to 8 carbon atoms, R ⁵
Is an alkylene group having 1 to 4 carbon atoms) by transesterification with an alkylamino alcohol represented by the following general formula (3): (Wherein each symbol is the same as described above), wherein the alkyl alcohol by-produced during the transesterification reaction is converted into an azeotrope with the alkyl (meth) acrylate. A method for producing an alkylamino (meth) acrylate, comprising distilling and purifying an obtained distillate with an ion exchange resin. 2. A compound of the general formula (1) Wherein R ¹ is a hydrogen atom or a methyl group, and R ² is an alkyl group having 1 to 4 carbon atoms, and an alkyl (meth) acrylate represented by the general formula (2): (Wherein, R ³ is a hydrogen atom or an alkyl group having 1 to 8 carbon atoms, R ⁴ is an alkyl group having 1 to 8 carbon atoms, R ⁵
Is an alkylene group having 1 to 4 carbon atoms) by transesterification with an alkylamino alcohol represented by the following general formula (3): (Wherein each symbol is the same as described above), a method for producing an alkylamino (meth) acrylate represented by the following formula (1): ) And heated from the top, alkylamino (meth) acrylate, alkyl (meth)
The acrylate and the alkylamino alcohol are distilled off, and (2) the distillate containing the alkylamino (meth) acrylate, alkyl (meth) acrylate and alkylaminoalcohol from the catalyst recovery unit (E) is separated into a light-boiling substance separation column (F ), And distillation is performed. (3) The bottoms from the light-boiling matter separation column (F) are supplied to the rectification column (G) for distillation.
The product alkylamino (meth) acrylate is taken out from the top of the column, and (4) the distillate containing the alkyl (meth) acrylate and the alkyl alcohol from the alcohol distillation column (B) is supplied to the ion exchange resin purification column (D). And producing the alkylamino (meth) acrylate. 3. A distillate containing an alkyl (meth) acrylate and an alkyl alcohol from an alcohol distillation column (B) is supplied to a distillation column (C) for distillation, and an alkyl (meth) acrylate from the top of the column is distilled. The method according to claim 2, wherein the distillate containing the alkyl alcohol is supplied to the ion-exchange resin purification column (D) for purification. 4. The method according to claim 1, wherein the purification with the ion exchange resin is performed in the coexistence of water. 5. A distillate containing an alkyl (meth) acrylate and an alkyl alcohol having a water content of 0.05 to 10%.
5. The method according to claim 4, wherein the amount is 0% by weight. 6. The method according to claim 1, wherein the ion exchange resin is an acidic ion exchange resin. 7. The method according to claim 1, wherein a distillate containing an alkyl (meth) acrylate purified with an ion exchange resin and an alkyl alcohol is used for producing an alkyl (meth) acrylate.