WO2003045894A1

WO2003045894A1 - Process for producing (meth)acrylic ester

Info

Publication number: WO2003045894A1
Application number: PCT/JP2002/012347
Authority: WO
Inventors: Shuhei Yada; Yasushi Ogawa; Yoshiro Suzuki; Kenji Takasaki
Original assignee: Mitsubishi Chemical Corporation
Priority date: 2001-11-27
Filing date: 2002-11-27
Publication date: 2003-06-05
Also published as: AU2002354063A1; CN1617847A; CN1304357C; CN1550489A

Abstract

A process for producing (meth)acrylic ester involving a step of washing and/or neutralizing a liquid reaction mixture containing (meth)acrylic ester and an oil-water separation step of separating an organic layer containing (meth)acrylic ester from a water layer formed in the washing and/or neutralization treatment, characterized in that it further comprises withdrawing a liquid containing the organic layer and the water layer. The method allows the prevention of troubles such as the clogging of a separation column in a low boiling point component separation step due to the deposition of a polymer or a sludge on a tray of the separation column or in a packed column or the clogging of a heating device due to the stick of foreigners therein, which leads to a stable operation of an apparatus for a long period of time.

Description

Specification

Method for producing (meth) acrylic acid ester

The present invention relates to a method for producing (meth) acrylic acid esters (acrylic acid esters and methyl methacrylate esters), and more particularly to a method for reacting (meth) acrylic acid and an alcohol in the presence of an acid catalyst to produce (meth) acrylic acid. For a method for producing an acid ester, more specifically,

The present invention relates to a method for producing a (meth) acrylic ester, comprising a step of washing and / or neutralizing a reaction solution containing a (meth) acrylic ester obtained by a reaction between a (meth) acrylic acid and an alcohol. Background art

Conventionally, (meth) acrylic acid esters are compounds having polymerizability, and can impart excellent properties to the resulting polymer, so that they can be used in various applications such as coatings, adhesives, and adhesives. It is widely used as a raw material for chemicals, synthetic resins and fibers.

As a method for producing a (meth) acrylic acid ester, a method for producing a (meth) acrylic acid ester by subjecting (meth) acrylic acid and an alcohol to an esterification reaction in the presence of an acid catalyst is generally widely used. Further, as a method for removing the acid catalyst after the reaction and unreacted (meth) acrylic acid from the obtained esterification reaction solution, a method of treating the esterification reaction solution with an aqueous solution of alcohol (Japanese Patent Laid-Open No. -99037, 61-243046, etc.). In order to remove the acid catalyst and unreacted (meth) acrylic acid by this method, an organic layer containing (meth) acrylic acid ester, and water and a neutralized salt generated by washing and / or neutralizing treatment are contained. When separating the water layer from the water layer, it is general that the water layer is separated by static separation using a separator such as a stationary tank. However, conventional stationary separation alone does not completely remove some of the neutralized salts and by-products such as polymer sludge contained in the esterification reaction solution that is an organic liquid. It is contained in a trace amount on the organic layer side. Therefore, if unreacted alcohol and by-products are further removed and distillation is performed to obtain high-purity (meth) acrylic acid ester, polymer sludge will be added to the tray or packed column of the light boiling component separation column. Foreign matter deposits such as light boiling point components There were problems when the separation tower was clogged, foreign matter adhered in the heater, causing blockage in the equipment, and foreign matter caught in the liquid sending pump, damaging the pump.

As a method of solving such a problem, for example, a surfactant is added to the above-mentioned two liquid layers (Japanese Patent Laid-Open No. 2001-48831), or separation is attempted using ultrasonic waves. (Japanese Patent Application Laid-Open No. Hei 10-108508) and various attempts to separate by centrifugal separator (Japanese Patent Application Laid-Open No. Hei 10-46569) have been made. It is necessary to introduce various drugs and equipment, and it seems that there are still problems in practical use. Posting the invention

The present invention overcomes such problems in the conventional production method, and efficiently removes some of the neutralized salts and by-products such as polymer sludge that could not be separated in a stationary tank, Provided is a method for stably producing a (meth) acrylic ester.

The present invention further provides a method for purifying these organic liquids by separating and removing insoluble components such as neutralized salts in organic liquids such as liquids containing alcohol, acrylic acid ester and methacrylic acid ester.

More specifically, the present invention relates to the production of alcohols and (meth) acrylic esters and the handling thereof, and the like, from the liquid containing alcohols and (meth) acrylic esters to neutralization salts such as neutralized salts. A step of separating and removing dissolved components is required. In such a step, a method is provided that enables long-term stable operation in the separation and purification step by distillation.

The present inventors have conducted various studies to solve the above problems, and as a result, have reached the present invention having the following features.

(1) A method for producing a (meth) acrylic ester by reacting (meth) acrylic acid with an alcohol in the presence of an acid catalyst, comprising: washing a reaction solution containing a (meth) acrylic ester; A step of separating the organic layer containing the (meth) acrylic acid ester from the organic layer containing the (meth) acrylate ester and the aqueous layer generated by the washing and / or the neutralization treatment, in the step of separating the organic layer and the aqueous layer. A method for producing a (meth) acrylic acid ester. (2) The method according to (1), wherein a part of the liquid containing the organic layer and the aqueous layer is a liquid near the interface between the organic layer and the aqueous layer.

(3) The method according to (1) or (2) above, wherein a part of the liquid containing the organic layer and the aqueous layer is extracted by an extraction nozzle provided near the interface between the organic layer and the aqueous layer.

(4) The method according to any one of the above (1) to (3), wherein a part of the liquid containing the organic layer and the aqueous layer is extracted from the extraction column for washing and / or neutralization.

(5) The method according to any one of (1) to (3) above, wherein a part of the liquid containing the organic layer and the aqueous layer is extracted from a standing tank for separating the organic layer and the aqueous layer.

(6) In the line pipe through which the organic liquid in the step of separating the organic layer and the aqueous layer passes and the line pipe through which the organic liquid taken out of the step or Z passes, the permeation particle size should be 1 to 1 μm. The method according to any one of the above (1) to (5), wherein a philosophy is set up.

(7) The method according to any one of the above (1) to (6), wherein the (meth) acrylate is methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate.

The present invention has the following features (a) to (k).

(a) reacting (meth) acrylic acid with an alcohol in the presence of an acid catalyst, and washing and / or neutralizing the obtained reaction solution containing (meth) acrylic acid ester to obtain (meth) acrylic acid In the method for producing a (meth) acrylate ester, the method includes the step of separating an organic layer containing an ester from an aqueous layer generated by washing and Z or neutralization. A method for producing a (meth) acrylate ester, comprising extracting a part.

(b) The method according to (a) above, wherein a part of the liquid near the interface between the organic layer and the aqueous layer is withdrawn in an extraction column for washing and / or neutralization.

(c) A part of the liquid in the vicinity of the interface between the organic layer and the aqueous layer is extracted, and the aqueous layer formed by washing and Z or neutralization that has leaked into the organic layer after passing through the extraction tower is statically removed. The method according to (a), wherein the method is performed in a stationary tank in which separation is performed in separated layers.

(d) The method according to any one of (a) to (c) above, wherein the (meth) acrylate is methyl acrylate, ethyl acrylate, butyl acrylate, or 2-ethylhexyl acrylate. (d) A method for purifying an organic liquid, comprising installing a filter having a permeation particle diameter of 1 to 10 wm in a line pipe through which an organic liquid containing an insoluble component passes.

(e) The method according to (d) above, wherein the organic liquid containing the insoluble component is an organic liquid containing a (meth) acrylate.

(f) An organic liquid containing an insoluble component undergoes an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to produce (meth) acrylic acid ester. The method according to the above (d), which is a liquid after removing impurities by a washing treatment and a water washing treatment.

(g) An organic liquid containing an insoluble component is subjected to an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to produce a (meth) acrylic acid ester. The method according to the above (d), which is a liquid obtained by extracting and recovering acrylic acid and a residual catalyst in the reaction using water.

(h) An organic liquid containing an insoluble component is subjected to an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to produce (meth) acrylic acid ester. The above-mentioned liquid after removing the salt generated by the treatment

The method described in (d).

(1) An organic liquid containing an insoluble component undergoes an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to form a (meth) acrylic acid ester. The method according to the above (d), which is a liquid after leaving, separating, and separating water generated by the water washing treatment and the neutralization treatment that has fallen into the storage tank.

(j) The method according to any one of (d) to (1) above, wherein the temperature at the time of passing through the filter is 90 or less.

(k) The method according to any one of the above (d) to (j), wherein the filter is replaced within a pressure difference (ΔΡ) of 1 kg / cm ² before and after passing through the filter. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is an explanatory view showing an example of an apparatus for implementing the present invention.

Figure 2: An explanatory diagram showing an example of a conventional device. FIG. 3 is an explanatory diagram of an example of a plant for producing a (meth) acrylate ester for carrying out the present invention.

Explanation of reference numerals

1: Extraction tower

2: Stationary tank

3: Extraction nozzle

4: Extracted liquid storage tank

1 1: Esterification reactor

1 2: Catalyst recovery tower

1 3: Washing tower

1 4: Stationary tank

15: Alcohol recovery tower

16: Light-boiling component removal tower Best mode for carrying out the invention

In the present invention, unreacted (meth) acrylic acid and an acid catalyst are removed from a reaction solution containing a (meth) acrylic acid ester produced by reacting (meth) acrylic acid with an alcohol in the presence of an acid catalyst. From the side of the equipment used in the oil-water separation process, such as an extraction tower that performs washing and / or neutralization to remove water, and a stationary tank that separates the liquid from the extraction tower and separates the organic layer and the aqueous layer. A liquid in an emulsion state at the interface between the organic layer and the aqueous layer. In a preferred embodiment, the organic layer containing the acrylic acid ester and the organic layer and the aqueous layer formed by washing and / or neutralizing treatment are neutralized. Part of the liquid near the interface is extracted. As a result, polymer present in the vicinity of the interface between the organic layer and the aqueous layer, by-products such as sludge, and neutral salts and the like contained in the esterification reaction solution are separated and removed.ゃ It has been found that leakage of by-products such as sludge and neutralized salts contained in the esterification reaction solution can be prevented, and the present invention is based on this.

FIG. 1 shows an example of an apparatus for implementing the present invention. The flow of the (meth) acrylic acid ester reaction liquid in this apparatus will be briefly described. First, the reaction solution obtained by the reaction between (meth) acrylic acid and alcohol is led to the extraction column 1, where water and Z or aqueous solution Cleaning and Z or neutralization treatment are performed using the liquid. In the extraction column 1, the organic layer containing (meth) acrylic acid and the aqueous layer generated by washing and / or neutralization are separated, and the reaction solution (organic layer) from which the esterification catalyst and (meth) acrylic acid are removed. The layer is then led to a standing tank 2 where the water generated by washing and Z or neutralization partially leaking is separated and separated. The obtained reaction liquid (organic layer) is sent to a step of separating light-boiling components, where appropriate separation treatment of light-boiling components is performed to obtain a (meth) acrylic acid ester.

When the separation tank 2 can sufficiently achieve the separation in the extraction column 1 such as when the extraction column 1 has a sufficient height, the above-mentioned stationary tank 2 does not need to be installed, and it is more economically advantageous. It is. When this stationary tank is not provided, the reaction liquid extracted from the extraction tower 1 is sent to the next step of separating the low boiling components.

In FIG. 1, the extraction nozzle 3 according to the present invention is provided in the extraction tower 1 and the stationary tank 2, respectively, and is used to separate the organic layer containing the (meth) acrylate ester from the aqueous layer generated by the washing and / or neutralization treatment. The liquid at the interface can be withdrawn. In addition, two continuous extraction towers (washing tower and neutralization tower) may be installed so that the washing and the neutralization treatment of the reaction solution are performed separately. May be provided.

Specific examples of the (meth) acrylate ester obtained by the present invention include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and (meth) acrylate. Alkyl or cycloalkyl esters of acrylic acid such as cyclohexyl acrylate, 2-ethylhexyl (meth) acrylate, polyfunctional (meta) such as ethylene glycol di (meth) acrylate and glycerin tri (meth) acrylate ) Atarilate and the like. Among the above compounds, butyl acrylate and 2-ethylhexyl acrylate are particularly preferred.

In addition, the alcohol can be the alcohol used as the ester raw material. However, these are not intended to limit the alcohols and (meth) acrylates of the present invention.

The present invention relates to an extraction column 1 for washing and / or neutralizing a (meth) acrylic acid ester reaction solution and / or an organic layer containing (meth) acrylic acid which is led after passing through the extraction column. The water layer generated by the washing and / or neutralization treatment is allowed to stand still, and then separated and separated. In the still tank 2, the organic layer containing the (meth) acrylic acid ester is washed and / or washed. Is used to separate by-products such as polymer sludge present at the interface with the aqueous layer obtained by the neutralization treatment and neutralized salts and the like contained in the esterification reaction solution before being sent to the light-boiling-point component separation step. By separating and removing, a purified (meth) acrylate reaction solution is obtained. The (meth) acrylate reaction liquid used in the present invention is produced, for example, through the following steps.

<(Meth) acrylate ester production process>

In the production of (meth) acrylic acid esters, generally, corresponding esters are produced from (meth) acrylic acid and alcohol by an esterification reaction in the presence of an acid catalyst. Usually, the raw materials (meth) acrylic acid and alcohol are supplied to the reactor in a molar ratio of from 1.0: 2.0 to 1.0: 0.5. The acid catalyst, which is a catalyst, is added at a ratio of 0.1 to 5.0% by weight, preferably 0.5 to 2.0% by weight, based on the reaction solution. The reaction is completed at a temperature of 70 to 180 by removing the water of reaction produced by the esterification reaction by distillation or azeotropic distillation (reactive distillation method). An inert azeotropic agent may be added to facilitate removal of the water of reaction. As the azeotropic agent, hydrocarbons such as benzene, toluene, and cyclohexane are often used. The reaction water may be removed by a method other than membrane separation such as a vapor separation membrane or a vaporization membrane, or distillation.

In addition, polymerization inhibitors and oxygen-containing gases are usually added to the reactor to prevent undesired polymerization of the (meth) acrylic acid and the corresponding ester.

After the completion of the esterification reaction, the reaction solution discharged from the reactor is preferably cooled to 10 to 6 Ot :.

The reaction solution contains unreacted (meth) acrylic acid, an ester corresponding to alcohol and an azeotropic agent as main components, a strong acid as a catalyst, and a trace amount of a polymerization inhibitor. Examples of the esterification catalyst include organic acids such as P-toluenesulfonic acid, benzenesulfonic acid, xylenesulfonic acid, and methanesulfonic acid, and mineral acids such as sulfuric acid and hydrochloric acid. <Washing process>

The (meth) acrylate reaction liquid obtained above is washed with water. The ratio of washing water is preferably 0.5 (weight ratio) or less with respect to the esterification reaction solution, and most preferably 0.2 to 0.5 (weight ratio). Water may be newly added. , Esterification reaction Reaction water obtained from a vessel can be used. In this case, there is an advantage that the amount of drainage can be reduced.

A general processing method can be applied as a cleaning method. For example, after mixing and stirring the washing water and the esterification reaction product, the washing water is separated and removed by standing separation, or the washing liquid and liquid-liquid separation are performed using a device such as a centrifuge. A method can be adopted. As a means for improving the washing effect, it is most preferable to use an extraction column. In the stirring / standing system, the reaction liquid and the washing water form an emulsion due to the strong stirring force, which sometimes makes liquid-liquid separation difficult. Since liquid-liquid contact is carried out at this point, formation of an emulsion is suppressed and liquid-liquid separation is facilitated.

As the type of the extraction tower, a conventional one can be used. An esterification reaction solution is supplied from the bottom of the extraction tower, a washing liquid is supplied from the top of the tower, and an esterification catalyst and the like are removed from the top of the tower. An aqueous solution containing the catalyst, (meth) acrylic acid, etc. is provided from the bottom of the extraction tower. The method obtained is general, but it should not be restricted. As the extraction column, a packed column, a column column and the like are generally used, but a device having high liquid-liquid contact efficiency is preferable.

Regarding water washing, one stage or multiple stages may be used.

The water-washed esterification reaction solution is further neutralized with an aqueous solution of alcohol, if necessary. As the extraction tower used in the neutralization step, the same extraction tower as that used in the above-mentioned washing step can be used.

Examples of the aqueous alkali solution used in the present invention include an aqueous solution of an alkali metal such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate or an alkali metal hydroxide or carbonate. Can be done. When neutralizing the (meth) acrylate reaction solution containing acidic water-soluble impurities, the pH of the esterification reaction solution is preferably adjusted to 9 or less in order to completely remove the acidic water-soluble impurities. Above, particularly preferably at least 11. If this is less than 9, the removal efficiency will decrease.

The organic layer containing (meth) acrylic acid ester obtained in the above washing and / or neutralization step is further left still in a still bath if necessary, and a part of the washing and / or Or By separating and removing water generated by the neutralization treatment, only the organic layer is sent to the light-boiling-point component separation step.

The installation location of the nozzle used for extraction, which is a feature of the present invention, is the extraction tower 1 and the stationary tank 2 used for the above-mentioned washing and neutralization. Regarding the installation position of the nozzle of the extraction tower 1 and the stationary tank 2, the flow rate of the (meth) acrylate reaction solution supplied to the extraction tower near the interface between the organic layer and the aqueous layer, washing and Z or neutralization treatment It is installed at the lower limit of the optimally determined range of the interface control set based on the supply flow rate of the water used for the extraction, the residence time of the extraction tower and the stationary tank, and the like. In this way, in the present invention, it is suitable to blow out a liquid near the interface, preferably within 20 cm, particularly preferably within 10 cm, from the interface between the organic layer and the aqueous layer.

The material of the nozzle used in the present invention is used for handling a liquid containing acrylic acid. S US 304, SUS 304 and SUS 316, SUS 316L, SUS 317, SU S 317L, SUS 329 J 1 L, SUS 329 J 2 Examples thereof include stainless steel such as L and nickel alloys such as hastelloys and inconels. Of these, SUS 304, SUS 304L and SUS 316 are preferable from the viewpoint of corrosion resistance and economy.

The extraction method is not particularly limited, but it is preferable to use both the extraction of the extraction tower and the extraction of the stationary tank in combination.

ADVANTAGE OF THE INVENTION According to this invention, precipitation and clogging in a light-boiling-point component isolation | separation process are prevented, and long-term stable driving | operation is attained.

The reason for this is that, for example, the production of butyl acrylate using p-toluenesulfonic acid as an acid catalyst is based on the analysis of insoluble solids extracted from the interface. Was 50% by weight, the sodium salt of acrylic acid was 30% by weight, and the butyl ester of polyacrylic acid was 15% by weight. It is considered that precipitation and clogging can be prevented.

FIG. 3 is an explanatory diagram of an example of a plant for producing a (meth) acrylate ester by carrying out an esterification reaction of (meth) acrylic acid and an alcohol in the presence of a catalyst according to the present invention. The black circles in Fig. 3 indicate the locations where the philippines are set up. As shown in Fig. 3, the alcohol and the raw material (meth) acrylic acid that were applied to the fill after removing the impurities are supplied to the esterification reactor 11 together with the acid catalyst. The reaction solution containing the generated (meth) acrylic acid ester is led to the catalyst recovery tower 12, where the unreacted (meth) acrylic acid and the residual acid catalyst are extracted and recovered, and filtered by a filter. Next, it is led to a washing tower, where it is washed and neutralized with water and an aqueous alkali solution, and the reaction solution separated from the aqueous layer is filtered. Further, the water generated by the washing and neutralization treatment with the partially leaked water in the stationary tank 14 is allowed to stand, separated, separated, passed through a filter, and led to a light boiling point component removal tower 16. I will The (meth) acrylic acid ester is obtained as a product from the top of the product tower.

In addition, the stationary tank 14 described above does not need to be installed when separation in the washing tower can be sufficiently achieved, such as when the washing tower has a sufficient height, and it is economically advantageous. It is. If this storage tank is not provided, the reaction liquid extracted from the washing tower is applied to the filter once and then sent directly to the light-boiling-point component removal tower in the next process.

The washing tower 13 in the above-mentioned brand may perform the washing with water and the neutralization treatment with the aqueous solution in separate columns, respectively, and the installation of the filter is not required in all of the above four places. It is effective to install it in the line piping after removing the water leaked partially by the stationary tank 14.

Examples of the organic liquid to be treated in the present invention include alcohols, (meth) acrylates, and organic liquids containing these. Specific examples of such (meth) acrylates are listed above as examples thereof. Same as the ones. Particularly preferred are butyl acrylate and 2-ethylhexyl acrylate. Further, the alcohol can be the alcohol used as the above-mentioned ester raw material. However, these do not limit the alcohols and (meth) acrylates of the present invention.

The present invention provides a method for purifying these organic liquids by removing insoluble components such as neutralized salts, polymers, and sludge from organic liquids containing alcohol and (meth) acrylate. As an industrial process requiring such a purification method, specifically, when producing a (meth) acrylate from (meth) acrylic acid and alcohol, unreacted (meth) acrylic acid and residual Step after recovery of acid catalyst with water, removal of unreacted (meth) acrylic acid and salts generated by reaction of residual acid catalyst with alkali The latter step includes a step after separating impurities such as peroxides in the raw material alcohol by pickling or washing with water, and the like, and is also used in various other steps. In a particularly preferable step, it is more preferable to set a filter in a step after removing unreacted (meth) acrylic acid or a salt generated by a reaction between the residual acid catalyst and the alkali. In the case where a standing tank is provided in the step after the above-mentioned salt removal, it is more preferable to set a filter after the standing tank.

The type of filter having a permeation particle diameter of 1 to 10 m used in the present invention is chemically stable to the feed liquid, does not contaminate the feed liquid, and removes insoluble components from the feed liquid. There is no particular limitation as long as it is possible.

As a material of such a filter, any material such as glass fiber, metal fiber, polyester, fluorocarbon, polyethylene, polypropylene, polyamide, polystyrene, cellulose, and cellulose acetate can be used. Polypropylene is more preferred because of acid resistance, alkali resistance, low production cost and the like. The temperature at the time of passing through the filter is preferably 90 or less, and more preferably 30 to 70. Above 90, the removal by the filter becomes insufficient. It is economically advantageous to manage the replacement of the fill at a pressure difference (ΔΡ) of less than 1 kg / cm ² before and after the passage of the fill. The filter used in the present invention has a transmission particle size of 1 to 10 μm, preferably 2 to 5 / _im. If the permeation particle size is smaller than this, the removal effect will increase, but the filter replacement frequency will increase, the differential pressure will increase, and the flow rate will decrease, which is not favorable in terms of process and economy. On the other hand, if the permeation particle size exceeds 10 / m, the effect of removing insoluble components is reduced, and as a result, long-term stable operation cannot be achieved. The replacement of the filter in the present invention is suitable because the pressure difference (ΔΡ) before and after the passage of the filter through the filter is preferably within 1 kg Z cm ² .

Example

Hereinafter, specific examples of the present invention are shown together with comparative examples, but the present invention is not limited to the following examples.

Example 1

A liquid containing 87% by weight of butyl acrylate, 7% by weight of toluene, 1% by weight of water, and 5% by weight of other unknown components was added to the extraction column 1 corresponding to the neutralization step in the flow of Fig. / hr Supplied with The liquid near the interface layer was drawn into the storage tank alternately at a frequency of 5 LZ hr / weekly from both the draw-out nozzle installed at the lower limit of the interface control meter and the draw-out nozzle 3 of the stationary tank 2. By performing this operation, butyl acrylate could be manufactured continuously for 100 days.

Comparative Example 1

Production was carried out in the same manner as in Example 1 using the flow shown in Fig. 2 without installing the extraction nozzle, but the operation was stopped in 40 days because the pressure difference inside the light boiling point component separation tower increased. .

Example 2

A liquid containing 87% by weight of butyl acrylate, 7% by weight of butanol, 1% by weight of water, and 5% by weight of other unknown components obtained by the esterification reaction of acrylic acid and butanol in the presence of a sulfuric acid catalyst. (Liquid at the outlet of the standing tank 14 in Fig. 3) at the temperature of 79, 12 t / hr,

After passing through a pipe equipped with a heat-welded polypropylene microfiber filter cartridge of 3 m or less, the liquid was sent to a light boiling point component separation tower. The feed was continued until a rise in the differential pressure in the light-boiling component separation column was observed. The exchange frequency of the filter was once Z 7 days, and the continuous operation of the light-boiling component separation column was 185 days.

Example 3

The same operation as in Example 2 was performed except that p_toluenesulfonic acid was used as a catalyst, and the number of continuous operation days of the light-boiling-point component separation column was 180 days.

Comparative Example 2

The same operation as in Example 2 was performed except that the filter was not installed.

On the 40th, the operation was stopped because the pressure difference inside the light boiling point component separation tower increased.

Comparative Example 3

The operation was performed in the same manner as in Example 2 except that the permeation particle size of the filter was set to 0.5 ^ m or less, and the filter had to be replaced once / day. The operation was stopped because the amount of liquid sent to the component separation tower was not stable.

Comparative example 4

The operation was performed in the same manner as in Example 2 except that the permeation particle size of the filter was adjusted to 15 ιτι or less. It has stopped. Comparative Example 5

The operation was performed in the same manner as in Example 2 except that the temperature during the liquid passing through the filter was set at 100, and the pressure difference in the light-boiling-point component separation tower increased 50 days after the liquid was fed. The operation was stopped. Industrial applicability

According to the present invention, in the (meth) acrylic acid ester production step, the organic layer containing the (meth) acrylic acid ester in the extraction column for washing and / or neutralizing treatment is obtained by washing and / or neutralizing treatment. Separation and removal of by-products such as polymer sludge present at the interface with the aqueous layer and neutralized salts contained in the esterification reaction solution before sending them to the light-boiling component separation step, thereby separating light-boiling components. Long-term stable operation of the process is possible, and as a result, it is possible to produce high-purity (meth) acrylic ester stably for a long period of time, which is very useful for producing (meth) acrylic ester.

Further, according to the present invention, unpurified (meth) acrylic acid ester by-produced from an organic liquid containing alcohol and (meth) acrylic acid ester through an esterification reaction step and a separation step is used. Since the dissolved components are efficiently separated and removed, it is possible to stably produce high-purity (meth) acrylate for a long period of time, which is very useful in producing (meth) acrylate.

Claims

The scope of the claims

1. A method for producing a (meth) acrylic acid ester by reacting (meth) acrylic acid with an alcohol in the presence of an acid catalyst, wherein the reaction solution containing the (meth) acrylic acid ester is washed and In the step of separating the organic layer containing the (meth) acrylic acid ester from the organic layer containing the (meth) acrylate and the aqueous layer generated by the washing and / or the neutralization treatment, a part of the liquid containing the organic layer and the aqueous layer A method for producing a (meth) acrylic acid ester.

2. The method according to claim 1, wherein a part of the liquid containing the organic layer and the aqueous layer is a liquid near the interface between the organic layer and the aqueous layer.

3. The method according to claim 1, wherein a part of the liquid containing the organic layer and the aqueous layer is extracted by an extraction nozzle provided near an interface between the organic layer and the aqueous layer.

4. The method according to any one of claims 1 to 3, wherein a part of the liquid containing the organic layer and the aqueous layer is extracted from the extraction column for washing and / or neutralization.

5. The method according to any one of claims 1 to 3, wherein a part of the liquid containing the organic layer and the aqueous layer is extracted from a stationary tank that separates the organic layer and the aqueous layer.

6. In the line pipe through which the organic liquid in the step of separating the organic layer and the aqueous layer passes and / or the line pipe through which the organic liquid taken out of the step passes, the transmission particle size is 1 to 1 O ^ m. The method according to any one of claims 1 to 5, wherein a filter is provided.

7. The method according to any one of claims 1 to 6, wherein the (meth) acrylate is methyl acrylate, ethyl acrylate, butyl acrylate or 2-ethylhexyl acrylate.

8. (Meth) Acrylic acid and alcohol are reacted in the presence of an acid catalyst, and the resulting (meth) acrylic ester-containing reaction solution is washed and treated or neutralized to give (Meth) a In the method for producing a (meth) acrylic acid ester, the method includes a step of separating an organic layer containing a acrylate from an aqueous layer formed by washing and Z or neutralization. A method for producing a (meth) acrylate ester, characterized in that a part of the (meth) acrylate is extracted.

9. The method according to claim 8, wherein a part of the liquid in the vicinity of the interface between the organic layer and the aqueous layer is extracted in an extraction column which performs washing and / or neutralization.

10. A part of the liquid in the vicinity of the interface between the organic layer and the aqueous layer was extracted, and the aqueous layer generated by washing and Z or neutralizing treatment leaked into the organic layer after passing through the extraction column was statically removed. 9. The method according to claim 8, wherein the method is carried out in a stationary tank in which the separated layer separation is performed.

11. The method according to any one of claims 8 to 10, wherein the (meth) acrylate is methyl acrylate, ethyl acrylate, butyl acrylate, or 21-ethylhexyl acrylate.

12. A method for purifying an organic liquid, comprising installing a filter having a permeation particle diameter of 1 to 10 in a line pipe through which an organic liquid containing an insoluble component passes.

13. The method according to claim 12, wherein the organic liquid containing the insoluble component is an organic liquid containing a (meth) acrylate.

14 4. An organic liquid containing an insoluble component undergoes an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to produce (meth) acrylic acid ester. 13. The method according to claim 12, wherein the liquid is a liquid that has been subjected to a washing treatment and a water washing treatment to remove impurities.

15 5. An organic liquid containing an insoluble component is less than a reaction liquid in a process of producing an ester of (meth) acrylate by subjecting (meth) acrylic acid and an alcohol to an esterification reaction in the presence of an acid catalyst. 13. The method according to claim 12, wherein the acrylic acid in the reaction is a liquid after the residual catalyst has been extracted and recovered using water.

16. An organic liquid containing an insoluble component undergoes an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to produce (meth) acrylic acid ester. The method according to claim 12, wherein the liquid is a liquid obtained by removing salts generated by the treatment.

17. The organic liquid containing the insoluble component undergoes an esterification reaction between (meth) acrylic acid and an alcohol in the presence of an acid catalyst to form a (meth) acrylic acid ester. 13. The method according to claim 12, wherein the liquid after standing, separating, and separating the water generated by the water washing treatment and the neutralization treatment that has fallen into the storage tank.

18. The method according to any one of claims 12 to 17, wherein the temperature at the time of passing through the fill is 90 or less.

19. The method according to any one of claims 12 to 18, wherein the filter is replaced within a pressure difference (ΔΡ) of about 1 kg / cm ² before and after passing through the filter.