JP5900657B2 - Method for producing polyfunctional (meth) acrylic acid ester - Google Patents

Description

The present invention relates to a method for producing a polyfunctional (meth) acrylic acid ester. More specifically, the present invention relates to an efficient method for producing a polyfunctional (meth) acrylic acid ester that does not use an aromatic hydrocarbon solvent in the production process and therefore has little adverse effect on the environment.
Furthermore, this invention relates to the method of manufacturing the polyfunctional (meth) acrylic acid ester with little coloring.

  In general, (meth) acrylic acid ester is produced by using esterification reaction of (meth) acrylic acid and alcohol in the presence of an acid catalyst. Since the monofunctional (meth) acrylic acid ester has a low boiling point, it is easy to purify the monofunctional (meth) acrylic acid ester by distillation from the reaction solution obtained by the above reaction.

  On the other hand, since polyfunctional (meth) acrylic acid esters have a high boiling point, purification by distillation is difficult like monofunctional (meth) acrylic acid esters. Therefore, first, the esterification reaction liquid containing the reaction solvent obtained by the esterification reaction is neutralized with an alkali. Thereafter, the (meth) acrylic acid ester separated from the resulting neutralized product is washed with water. By this washing operation, the alkali component, acid catalyst and unreacted (meth) acrylic acid remaining in the (meth) acrylic acid ester are removed (Patent Document 1).

  In the production of the polyfunctional (meth) acrylic acid ester, various organic solvents are used in the esterification reaction, neutralization treatment and water washing treatment. As these organic solvents, there are aromatic hydrocarbon compounds such as toluene, xylene and benzene which are good solvents for a wide variety of (meth) acrylic acid esters.

  However, aromatic hydrocarbon compounds are subject to regulation as substances that are suspected of having a negative effect on the human body in the Law Concerning Determination of Emissions of Specific Chemical Substances into the Environment and Promotion of Improvement of Management (PRTR Law in Japan). It has become. For this reason, the use of large amounts of aromatic hydrocarbon compounds tends to be restricted for the purpose of solving problems in the working environment at the manufacturing site, problems of air pollution due to discharge to the atmosphere, problems of sick houses, etc. .

  For the above reasons, aliphatic hydrocarbon compounds and alicyclic hydrocarbon compounds are used in the production of polyfunctional (meth) acrylic esters instead of the aromatic hydrocarbon compounds conventionally used as organic solvents. (Patent Document 2).

  However, aliphatic hydrocarbon compounds and alicyclic hydrocarbon compounds have poor compatibility with polyfunctional (meth) acrylic acid esters. Therefore, aliphatic hydrocarbon compounds and the like are often difficult to use as the solvent for the washing step. As a result, aromatic hydrocarbon compounds such as toluene and xylene are often used in combination with aliphatic hydrocarbon compounds (Patent Document 3).

  On the other hand, the present inventors have found that a polyfunctional (meth) acrylic acid ester can be produced by using a ketone compound instead of an aromatic hydrocarbon compound as an organic solvent in the washing step. However, the polyfunctional (meth) acrylic acid ester obtained by this method is easily colored. Therefore, the use of the polyfunctional (meth) acrylic acid ester produced by this method may be limited.

JP 2001-48831 A JP 2007-182418 A JP-A-2-306938

  The first object of the present invention is to avoid the use of an aromatic hydrocarbon compound whose influence on the environment has become a problem as an organic solvent, so that a polyfunctional product containing no aromatic hydrocarbon compound in the final product ( The object is to provide a method for producing a (meth) acrylic acid ester.

  The second object of the present invention is to provide a method for producing a polyfunctional (meth) acrylic acid ester with little coloring.

  As a result of intensive studies to solve the above problems, the present inventors can produce a polyfunctional (meth) acrylic acid ester not containing an aromatic hydrocarbon compound by selectively using a specific organic solvent shown below. As a result, the production method of the polyfunctional (meth) acrylic acid ester (first invention) has been completed.

  Furthermore, a method for neutralizing part or all of the acid catalyst was developed before adding the ketone compound as an organic solvent in the washing step. According to this method, it is possible to produce a polyfunctional (meth) acrylic acid ester that does not contain an aromatic hydrocarbon compound and is less colored (second invention).

That is, the first aspect of the present invention is
(1) An aliphatic hydrocarbon compound and / or an alicyclic hydrocarbon compound having 6 to 12 carbon atoms and a boiling point of 40 to 160 ° C. at atmospheric pressure is used as a reaction solvent in the presence of an acid catalyst ( ) Esterification reaction step of esterifying acrylic acid and polyhydric alcohol to obtain a reaction liquid containing polyfunctional (meth) acrylic acid ester;
(2) The dilution treatment step of adding an organic solvent composed of at least a ketone compound and / or an ester compound and the neutralization treatment step of adding an alkaline aqueous solution to the reaction liquid obtained in the esterification reaction step in any order Or a dilution / neutralization treatment step for obtaining a dilution / neutralization treatment solution by carrying out simultaneously,
(3) An organic phase recovery step of obtaining an organic phase by separating the diluted / neutralized treatment solution obtained in the dilution / neutralization step into an aqueous phase and an organic phase;
(4) a water washing step of washing the recovered organic phase with water;
(5) A polyfunctional (meth) acrylic acid obtained by separating the polyfunctional (meth) acrylic acid ester from the organic solvent by distilling off the organic solvent from the washed organic phase. An ester isolation step;
It is a manufacturing method of the polyfunctional (meth) acrylic acid ester which has this.

The second aspect of the present invention
(1) An aliphatic hydrocarbon compound and / or an alicyclic hydrocarbon compound having 6 to 12 carbon atoms and a boiling point of 40 to 160 ° C. at normal pressure is used as a reaction solvent in the presence of an acid catalyst ( An esterification reaction step in which a reaction liquid containing a polyfunctional (meth) acrylic acid ester is obtained by an esterification reaction of (meth) acrylic acid and a polyhydric alcohol;
(6) An acid catalyst neutralization step for obtaining an acid catalyst neutralization reaction liquid by adding at least 1/2 equivalent of an alkali component to the prepared acid catalyst in the obtained reaction liquid;
(7) A solvent comprising a ketone compound is added to the acid catalyst neutralization reaction solution to dilute the acid catalyst neutralization reaction solution, and alkali water is added to neutralize unreacted (meth) acrylic acid. A dilution / neutralization step to obtain a reaction mixture;
(8) An organic phase recovery step of separating the dilution / neutralization treatment liquid obtained in the dilution / neutralization step into an organic phase and an aqueous phase, and recovering the organic phase;
(9) a water washing step of washing the recovered organic phase with water;
(10) separating the polyfunctional (meth) acrylic acid ester from the organic solvent by distilling off the organic solvent from the washed organic phase, and isolating the polyfunctional (meth) acrylic acid ester;
It is a manufacturing method of the polyfunctional (meth) acrylic acid ester which has this.

  The production methods of the first and second inventions do not use an aromatic hydrocarbon compound in the production process. For the above reasons, the polyfunctional (meth) acrylic acid ester which is the final product obtained does not contain an aromatic hydrocarbon compound. Therefore, the influence on the health of people involved in the production of polyfunctional (meth) acrylic acid esters, those who use polyfunctional (meth) acrylic acid esters, or the environment is extremely small.

  Furthermore, according to the manufacturing method of the second invention, the final product is less colored. Therefore, it can be suitably used for applications such as a clear coat, a transparent film, and an adhesive that bonds sheets, where coloring of the product is a problem.

  Hereinafter, the present invention will be described in detail. In the present specification, (meth) acrylic acid means acrylic acid and methacrylic acid.

(First invention)
The first invention includes the following first step (esterification reaction step (1)) and second step (dilution / neutralization treatment step (2), organic phase recovery step (3), water washing step (4), and many The present invention relates to a method for producing a polyfunctional (meth) acrylic acid ester having a functional (meth) acrylic acid ester isolation step (5)).

  In the first step, (meth) acrylic acid and a polyhydric alcohol are stirred and mixed in the presence of an acid catalyst, and an esterification reaction is performed to obtain a reaction liquid containing a polyfunctional (meth) acrylic acid ester. The esterification reaction step.

  In the second step, an organic solvent and an aqueous alkali solution are added to the reaction solution obtained in the first step to neutralize the reaction solution, and then the neutralized reaction solution is separated into two phases, an organic phase and an aqueous phase. The organic phase is separated, the obtained organic phase is washed with water, and finally the polyfunctional (meth) acrylic acid ester is isolated.

  The polyfunctional (meth) acrylic acid ester produced by the production method of the first invention is not particularly limited as long as it is a compound having two or more (meth) acryloyl groups in one molecule.

  Specifically, (meth) acrylic acid ester of pentaerythritol, (meth) acrylic acid ester of dipentaerythritol, (meth) acrylic acid ester of tripentaerythritol, polyoxyethylene and / or polyoxypropylene bisphenol A ether (Meth) acrylic acid ester, (meth) acrylic acid ester of polyoxyethylene and / or polyoxypropylene bisphenol F ether, (meth) acrylic acid ester of polyethylene glycol, (meth) of tris (2-hydroxyethyl) isocyanurate Acrylic esters, (meth) acrylic esters of polybasic acids and polyhydric alcohols, (meth) acrylic esters of trimethylolpropane, (meth) acrylates of ditrimethylolpropane (Meth) acrylic acid ester of poly (propyl) glycol, (meth) acrylic acid ester of polyoxyethylene and / or polyoxypropylene trimethylolpropane ether, (meth) acrylic acid ester of polyoxyethylene and / or polyoxypropylene pentaerythritol ether ) Acrylic acid ester and the like are exemplified.

  Among these polyfunctional (meth) acrylic acid esters, polyfunctional (meth) acrylic acid esters that are hardly compatible with a solvent composed of an aliphatic hydrocarbon compound or an alicyclic hydrocarbon compound are preferable.

  Such polyfunctional (meth) acrylic acid esters include pentaerythritol (meth) acrylic acid ester, dipentaerythritol (meth) acrylic acid ester, tripentaerythritol (meth) acrylic acid ester, polyoxyethylene and (Meth) acrylic acid ester of polyoxypropylene bisphenol A ether, (meth) acrylic acid ester of polyoxyethylene and / or polyoxypropylene bisphenol F ether, (meth) acrylic acid ester of polyethylene glycol, isocyanuric acid tris ( Examples include (meth) acrylic acid ester of 2-hydroxyethyl), and (meth) acrylic acid ester of polyester composed of polybasic acid and polyhydric alcohol.

  In the first step (esterification reaction step (1)), (meth) acrylic acid and polyhydric alcohol are stirred and mixed in the presence of an acid catalyst to promote the esterification reaction. This is an esterification reaction step for obtaining a reaction solution containing an acrylate ester.

  The esterification reaction may be performed according to a conventional method. Usually, a method of heating and stirring (meth) acrylic acid and a polyhydric alcohol in the presence of an acid catalyst in an organic solvent can be used.

  What is necessary is just to use what corresponds to the said polyfunctional (meth) acrylic acid ester as a polyhydric alcohol. The number of OH groups in one molecule of the polyhydric alcohol is preferably 2 or more, and more preferably 2 to 10.

Specific examples of polyhydric alcohols include polycyclic alkyl dialcohols such as tricyclodecane dimethylol; alkylene glycols such as ethylene glycol, propylene glycol, pentanediol and hexanediol; diethylene glycol, triethylene glycol, tetraethylene glycol, polyethylene Polyalkylene glycols such as glycol, dipropylene glycol, tripropylene glycol and polypropylene glycol; glycerins such as glycerin and diglycerin;
Examples include bisphenol alkylene oxide adducts such as glycerin alkylene oxide adducts, bisphenol A alkylene oxide adducts, and bisphenol F alkylene oxide adducts.

Furthermore, polyols such as trimethylolpropane, ditrimethylolpropane, pentaerythritol and dipentaerythritol and alkylene oxide adducts of these polyols; isocyanuric acid alkylene oxide adducts, polyester polyols, and the like.
Examples of the alkylene oxide in the alkylene oxide adduct include ethylene oxide and propylene oxide. Moreover, as addition number of alkylene oxide, 1-20 are preferable.

  What is necessary is just to set the usage-amount of (meth) acrylic acid suitably according to the (meth) acrylic acid ester made into the objective. Usually, when the number of hydroxyl groups in one molecule of the polyhydric alcohol is n, 0.7 n to 2.0 nmol is preferable and 0.9 n to 1.5 nmol is more preferable with respect to 1 mol of the polyhydric alcohol.

  Examples of the acid catalyst include mineral acids such as hydrochloric acid, phosphoric acid, and sulfuric acid, and sulfonic acids such as p-toluenesulfonic acid, methanesulfonic acid, and trifluoromethanesulfonic acid.

  As a usage-amount of an acid catalyst, 0.1-10 mass% is preferable with respect to the total mass of the reaction liquid containing the organic solvent mentioned later.

The esterification reaction may be carried out according to a conventional method.
What is necessary is just to set reaction temperature suitably according to the raw material to be used and the objective. From the viewpoint of shortening the reaction time and preventing polymerization, the reaction temperature is preferably 65 to 140 ° C, more preferably 75 to 120 ° C. By setting the reaction temperature to 65 ° C. or higher, the esterification reaction rate can be increased and the yield can be prevented from decreasing. On the other hand, thermal polymerization of (meth) acrylic acid or (meth) acrylic acid ester to be generated can be prevented by setting the reaction temperature to 140 ° C. or lower.

  The pressure during the reaction may be normal pressure or reduced pressure. In order to prevent thermal polymerization of (meth) acrylic acid or (meth) acrylic acid ester to be produced, it is preferable to carry out the reaction under reduced pressure for the purpose of lowering the reaction temperature.

  In the esterification reaction, water is generated as the reaction proceeds. It is preferable to promote the esterification reaction by removing the generated water from the reaction system by azeotroping with an organic solvent.

  The organic solvent used for the esterification reaction is an aliphatic hydrocarbon compound having 6 to 12 carbon atoms, preferably 6 to 10 carbon atoms, and having a boiling point at atmospheric pressure of 160 ° C. or lower, preferably 40 to 140 ° C. and / or It is an alicyclic hydrocarbon compound.

Examples of the organic solvent used in the esterification reaction include aliphatic hydrocarbon compounds such as n-hexane, n-heptane, n-octane, isooctane, nonane, 2-methyloctane, and 2,6-dimethyloctane, cyclohexane, and cycloheptane. And alicyclic hydrocarbons such as methylcyclohexane, cyclooctane and 1-methyl-4-ethylcyclohexane.
Among these, n-hexane, cyclohexane, methylcyclohexane, n-heptane and isooctane are preferable from the viewpoint of versatility.

  The amount of the organic solvent used is 0.05 to 2.0 times the total amount of the polyhydric alcohol and (meth) acrylic acid, and the esterification reaction proceeds smoothly, in the reaction solution. Considering removal of water and the like, 0.1 to 1.0 mass times is more preferable.

  In the esterification reaction, it is preferable to carry out the reaction in the presence of oxygen in order to prevent polymerization, and for the same purpose, it is preferable to add a polymerization inhibitor to the reaction solution.

  Examples of the polymerization inhibitor include organic compounds and metal salts. Examples of organic compounds include benzoquinone, hydroquinone, catechol, diphenylbenzoquinone, hydroquinone monomethyl ether, naphthoquinone, t-butylcatechol, t-butylphenol, dimethyl-t-butylphenol, t-butylcresol, dibutylhydroxytoluene, gallic acid, gallic acid Examples include acid esters and phenothiazines.

  Examples of the metal salt include copper compounds such as cupric chloride and copper sulfate, and iron compounds such as ferrous sulfate.

  The addition amount of the polymerization inhibitor is 10 to 50,000 ppm on a mass basis, preferably 100 to 10,000 ppm, based on the amount of (meth) acrylic acid used as a raw material. If the addition amount is 10 ppm or more, there is no practical problem, but if it is 100 ppm or more, the polymerization preventing effect can be sufficiently exhibited. By making the addition amount 10,000 ppm or less, it is possible to prevent coloring of the (meth) acrylic acid ester to be produced and a decrease in polymerization curability of the (meth) acrylic acid ester.

  The degree of progress of the esterification reaction is monitored by monitoring the amount of water produced by the esterification reaction (ie, the amount of dehydration), measuring the concentration of acid ((meth) acrylic acid and acid catalyst) in the reaction solution, It can be judged by analyzing the content of the product (meth) acrylate and comparing it with the intended composition.

  Specific examples of the reaction in the presence of oxygen include a reaction in an atmosphere of an oxygen-containing gas and a method of reacting while introducing an oxygen-containing gas into a reaction solution. A typical oxygen-containing gas is air. Industrially, an oxygen-containing gas having an oxygen concentration of 3 to 15% by volume is preferably used in consideration of the danger of flammable explosion. The oxygen-containing gas can be prepared by mixing oxygen or air and an inert gas. Nitrogen or argon is commonly used as the inert gas.

(Second step)
After the first step, the second step is performed. Before performing the second step, the second step may be performed after the organic solvent in the reaction solution obtained in the first step is removed and collected by a method such as distillation.

  In summary, the second step is to dilute and neutralize the reaction solution obtained in the first step by adding an organic solvent and an aqueous alkali solution, and then separate the solution into two phases, an organic phase and an aqueous phase. This is a step of separating the organic phase and recovering the (meth) acrylic acid ester.

  By adding an aqueous alkali solution to the reaction solution obtained in the first step and separating it into two phases, the unreacted (meth) acrylic acid and the acid catalyst such as the acid catalyst are transferred from the reaction solution to the aqueous phase, Can be removed.

  Furthermore, it can isolate | separate efficiently into two phases by adding an organic solvent to the reaction liquid obtained at a 1st process.

The second step includes a dilution / neutralization treatment step, an organic phase recovery step, a water washing step, and a polyfunctional (meth) acrylic acid ester separation step.
The reaction solution obtained in the first step is then treated in the dilution / neutralization treatment step (2) of the second step.

  The dilution / neutralization treatment step (2) includes a dilution treatment step of adding an organic solvent composed of at least a ketone compound and / or an ester compound to the reaction solution obtained in the esterification reaction step, and a neutralization treatment of adding an alkaline aqueous solution. And a step of obtaining a dilution / neutralization treatment liquid by performing the steps in any order or simultaneously.

  The dilution / neutralization treatment step includes a dilution treatment step and a neutralization treatment step, and these steps may be performed first or simultaneously.

  In the alkaline aqueous solution used in the neutralization treatment step, the alkaline components include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal salts such as sodium carbonate, and alkaline earth metal waters such as calcium hydroxide. An oxide etc. are mentioned. Among these, an alkali metal hydroxide is preferable in that the neutralizing effect is excellent.

  The amount of the alkali component in the aqueous alkali solution added in the neutralization treatment step is preferably 1 or more, and more preferably 1.0 to 1.6 times in terms of molar ratio to the acid content of the reaction solution. When the addition amount of the alkali component is within the above range, neutralization of the acid content is sufficiently performed.

  The concentration of the alkaline aqueous solution is preferably 1 to 25% by mass, more preferably 3 to 25% by mass, and particularly preferably 10 to 25% by mass. By making the concentration of the alkaline aqueous solution 1% by mass or more, it is possible to prevent an increase in the amount of drainage after the neutralization treatment. By setting the concentration of the alkaline aqueous solution to 25% by mass or less, polymerization of the polyfunctional (meth) acrylic acid ester can be prevented.

  In addition, the said neutralization process can also be implemented in multiple times.

  The organic solvent used in the dilution treatment step in the dilution / neutralization step (2) of the second step is a ketone compound and / or an ester compound.

  Examples of the ketone compound include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone.

  Examples of ester compounds include acetates such as methyl acetate, ethyl acetate, n-propyl acetate, isopropyl acetate and butyl acetate, methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, (meth) Examples include (meth) acrylic acid esters such as isobutyl acrylate and butyl (meth) acrylate.

  Among these, ketone compounds and / or ester compounds having 3 to 8 carbon atoms and a boiling point of 160 ° C. or less, preferably 40 to 140 ° C. at normal pressure are preferable from the viewpoint of acid removal efficiency.

  Specifically, methyl ethyl ketone, methyl isobutyl ketone, isopropyl acetate, n-propyl acetate, butyl acetate, isobutyl acetate and tert-butyl acetate are particularly preferable.

  These ketone compounds and / or ester compounds may be used alone or in admixture of two or more, and may also be used in admixture with other organic solvents other than ketone compounds and ester compounds.

  The amount of the organic solvent composed of the ketone compound and / or ester compound is preferably 0.2 to 10 times the total mass of (meth) acrylic acid and polyhydric alcohol. 4-5.0 mass times is more preferable.

  In the dilution / neutralization treatment step, the reaction solution, the organic solvent and the alkaline aqueous solution are preferably supplied to a tank-type apparatus and stirred for treatment, or treated using a static mixer or the like.

Before carrying out the neutralization treatment, a preliminary washing treatment of the reaction solution can be performed using a water detergent.
In particular, when using a copper-based polymerization inhibitor in the esterification reaction step, the copper-based polymerization inhibitor can be efficiently removed by performing a preliminary water washing treatment.

Specific examples of the preliminary water washing treatment step include a method of adding a water detergent to the reaction solution obtained by the esterification reaction, stirring and mixing, and the like.
As the water detergent, an aqueous solution of an inorganic substance such as pure water, an aqueous sodium chloride solution, or an aqueous ammonium sulfate solution can be used. The content of the inorganic substance in the water detergent is preferably a concentration equal to or lower than the solubility of the inorganic substance at the operating temperature.

  The dilution / neutralization treatment solution obtained by treating the reaction solution in the dilution / neutralization treatment step (2) is then phase-separated into two phases, an organic phase and an aqueous phase, in the organic phase recovery step (3). The organic phase is separated. Examples of the method for separating the organic phase include a method of extracting an aqueous phase that is a lower layer of two separated phases.

  The separated organic phase is washed with water in the washing step (4). As the water detergent used for washing with water, the water detergent used in the preliminary washing process can be used, and water is particularly preferred.

In the isolation step (5) of the polyfunctional (meth) acrylic acid ester, the organic solvent is distilled off from the separated organic phase after phase separation into two phases of the organic phase and the aqueous phase. Isolate the meth) acrylate.
The organic solvent may be distilled off according to a conventional method. For example, the method of removing an organic solvent using the desolvation tank made into pressure reduction, etc. are mentioned. What is necessary is just to set suitably as a vacuum degree of a solvent removal tank according to the raw material to be used and the objective, Preferably it is 0.5-50 kPa, and the method of increasing a pressure reduction degree gradually according to the removal degree of an organic solvent is preferable.

  In order to prevent thermal polymerization of the (meth) acrylic acid ester, the organic solvent is distilled off by supplying oxygen or adding a polymerization inhibitor and setting the solvent distillation temperature at, for example, 20 to 80. It is preferable to carry out under reduced pressure so that it may maintain at ° C.

  If necessary, the organic solvent is removed from the organic phase in a desolvation tank, a filter aid is supplied to the desolvation tank, and the filter aid is applied to a vertical horizontal filter type filter connected to the desolvation tank. By depositing, the reaction product can be filtered.

  The aqueous phase and washing water separated in the organic phase recovery step and washing treatment can be treated as waste water by a known method.

(Second invention)
Hereinafter, the second invention will be described in detail.
The second invention can be summarized as the following first step (esterification reaction step (5)) and second step (acid catalyst neutralization step (6), dilution / neutralization step (7), organic layer recovery step). The present invention relates to a method for producing a polyfunctional (meth) acrylate ester, which comprises (8), a water washing step (9) and a step (10) for isolating a polyfunctional (meth) acrylate ester.

  In the first step, in the presence of an acid catalyst, (meth) acrylic acid and a polyhydric alcohol are stirred and mixed, and an esterification reaction is performed to obtain a reaction liquid containing a polyfunctional (meth) acrylic acid ester. This is the chemical reaction step (1).

  In the second step, an alkali component is added to the reaction solution obtained in the first step to neutralize at least half of the acid catalyst, and then unreacted (meth) acrylic acid, acid catalyst, etc. are removed. For this purpose, a ketone compound as an organic solvent and an aqueous alkali solution are added to separate the organic phase into an aqueous phase and the organic phase is separated to recover the polyfunctional (meth) acrylic acid ester.

The polyfunctional (meth) acrylic acid ester obtained by the production method of the second invention is not particularly limited as long as it is a compound having two or more (meth) acryloyl groups. Specifically, it is the same as the first invention.
The esterification reaction step (1), which is the first step, is the same as the esterification reaction step in the first invention.

(Second step)
After the end of the first step, the second step is performed. In the second step, first, an alkali component is added to the reaction solution obtained in the first step to neutralize at least 1/2 of the acid catalyst (1/2 to all of the acid catalyst) (acid catalyst neutralization). Step (6)). Thereafter, for the purpose of removing unreacted (meth) acrylic acid, a polymer of (meth) acrylic acid, etc., a ketone compound as an organic solvent and an alkaline aqueous solution are added (dilution / neutralization step).

  There is no restriction | limiting in the addition order of an organic solvent and aqueous alkali solution, which may be added first and may add these simultaneously.

  Subsequently, it is made to phase-separate into two phases, an organic phase and an aqueous phase. Thereafter, the phase-separated organic phase is separated (organic layer recovery step (8)), and the resulting organic layer is washed with water (water washing step (9)) to recover the polyfunctional (meth) acrylic acid ester (multifunctional) Step (10) for isolating (meth) acrylic acid ester.

  In addition, in the second step, before adding the organic solvent, the reaction solvent (aliphatic hydrocarbon compound and / or alicyclic hydrocarbon compound) used in the first step is removed and recovered by a method such as distillation. Also good.

  The alkali component for neutralizing the acid catalyst may be added before adding the ketone compound of the organic solvent, and may be before or after removing / recovering the reaction solvent used in the first step.

  Examples of the alkali component used for neutralization of the acid catalyst include alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, alkali metal salts such as sodium carbonate, and alkaline earth metal hydroxides such as calcium hydroxide. Is exemplified.

Although the form of the alkali component used for neutralization of the acid catalyst is not limited, the form of an aqueous solution is preferable because it is easily added and mixed.
The addition amount of the alkali component used for neutralization of the acid catalyst is preferably 1/2 equivalent times or more, more preferably 2/3 equivalent times or more, relative to the charged acid catalyst. When the ratio of the acid catalyst to be neutralized is less than 1/2 equivalent to the charged catalyst, it is difficult to obtain a product (meth) acrylic ester with little coloring.

  The organic solvent used in the dilution / neutralization step (7) in the second step is a ketone compound. Specific examples include acetone, methyl ethyl ketone, methyl isobutyl ketone, cyclopentanone, and cyclohexanone.

  Among these, a ketone compound having 3 to 8 carbon atoms and a boiling point at atmospheric pressure of 160 ° C. or lower, preferably 40 to 140 ° C., and methyl ethyl ketone and methyl isobutyl ketone are particularly preferable because the organic solvent can be easily removed.

  The ketone compounds may be used alone or in combination of two or more, and may be used by mixing with other organic solvents other than the ketone compound. Examples of such other solvents include aliphatic hydrocarbon compounds such as n-hexane, n-heptane, n-octane, isooctane, nonane, 2-methyloctane, and 2,6-dimethyloctane, cyclohexane, cycloheptane, and methyl. Examples include alicyclic hydrocarbons such as cyclohexane, cyclooctane and 1-methyl-4-ethylcyclohexane.

  The used amount of the ketone compound is 0.2 to 0.2 of the total mass of the residual mass of the reaction solvent used in the first step, the mass of (meth) acrylic acid blended in the first step, and the mass of the polyhydric alcohol. It is preferably 10 times by mass, and particularly preferably 0.4 to 5.0 times by mass from the viewpoint of the effect of removing the organic solvent.

  In the dilution / neutralization step (7), the alkali component added to the reaction solution for the purpose of neutralizing acid content such as unreacted (meth) acrylic acid is alkali metal water such as sodium hydroxide and potassium hydroxide. Examples include oxides, alkali metal salts such as sodium carbonate, and alkaline earth metal hydroxides such as calcium hydroxide. This alkali component may be the same as or different from the alkali component used for neutralization of the acid catalyst. Among these alkali components, alkali metal hydroxides are preferable in that they are excellent in neutralizing and removing effects.

The alkaline component is preferably added to the reaction solution in the form of an aqueous solution. As for the density | concentration of the aqueous alkali solution to be used, 1-25 mass% is preferable, More preferably, it is 3-25 mass%, Most preferably, it is 10-25 mass%. When the concentration of the alkaline aqueous solution is 1% by mass or more, it is possible to prevent the amount of drainage after the neutralization treatment from increasing. When the concentration of the alkaline aqueous solution is 25% by mass or less, polymerization of the polyfunctional (meth) acrylic acid ester can be prevented.
The neutralization treatment can be carried out in a plurality of times.

  The addition amount of the alkali component added to the reaction solution for the purpose of neutralizing the acid content such as unreacted (meth) acrylic acid is based on the number of moles of acid content such as unreacted (meth) acrylic acid. The molar ratio is preferably 1 or more, and more preferably 1.0 to 1.6. By adding an alkali component within the above molar ratio range, neutralization and removal of acid content such as unreacted (meth) acrylic acid is sufficiently performed.

The reaction mixture obtained by the neutralization treatment in the dilution / neutralization step (7) is preferably washed with a water detergent.
As the water detergent, pure water and an aqueous solution of an inorganic salt such as an aqueous sodium chloride solution or an aqueous ammonium sulfate solution can be used. The water washing treatment can be carried out in a plurality of times.

The dilution / neutralization step is not particularly limited, but a preferable method includes a method using a tank-type apparatus while stirring or a method using a static mixer or the like.
After performing the dilution / neutralization step, the reaction mixture obtained in the dilution / neutralization step is phase-separated into two phases, an organic phase and an aqueous phase, the organic phase is separated, and the resulting organic layer is washed with water, By distilling off the solvent of the layer, the polyfunctional (meth) acrylic acid ester can be recovered.

In addition, before implementing a neutralization process, the reaction liquid can be washed with water for various purposes.
In particular, when a copper polymerization inhibitor is used in the esterification reaction step, the copper polymerization inhibitor can be efficiently removed by washing the reaction solution obtained in the first step with water. .

As a method for washing the reaction solution with water, a conventional method may be used, and the reaction solution may be washed with water in the same manner as the water washing treatment after the neutralization treatment.
As the water detergent, pure water, an aqueous solution of an inorganic substance such as an aqueous solution of sodium chloride and an aqueous solution of ammonium sulfate can be used.

  In the second invention, the organic layer recovery step (8), the water washing step (9) and the step (10) of isolating the polyfunctional (meth) acrylic acid ester are the organic layer recovery step (8) in the first invention. ), The water washing step (9) and the polyfunctional (meth) acrylic acid ester can be carried out by the same operation as the isolation step (5).

  Hereinafter, the first aspect of the present invention will be described more specifically with reference to examples and comparative examples. In the following, “%” means mass%. ppm is mg / kg.

(Example of the first invention, comparative example)
(Example 1)
In a 3 L four-necked flask equipped with a reflux tube, 628.1 g of dipentaerythritol, 1281.9 g of acrylic acid, 112.0 g of paratoluenesulfonic acid monohydrate (hereinafter referred to as PTS), cupric chloride 3.0 g and 675.0 g of cyclohexane were added. While oxygen-containing gas (oxygen 5 vol%, nitrogen 95 vol%) was blown into the flask, the mixture was heated and stirred at a reaction liquid temperature of 75 to 80 ° C. With the progress of the reaction, the dehydrated esterification reaction was carried out for 13 hours while removing the produced water out of the system with a Dean-Stark tube.

  After completion of the reaction, 2000.0 g of n-propyl acetate was added to the reaction solution for dilution, and 150 g of distilled water was further added. By sufficiently stirring, the reaction solution was washed with water and then allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed.

  Next, a 20% aqueous sodium hydroxide solution is added to the organic solvent phase to neutralize the acid component contained in the organic solvent phase, and the mixture is allowed to stand, and the aqueous phase (lower layer) and the organic solvent phase (upper layer) are separated into layers. The lower aqueous phase was removed and the organic solvent phase was recovered. Further, 450 g of distilled water was added to the recovered organic solvent phase, washed with water, and allowed to stand. The separated aqueous phase (lower layer) was removed, and the upper organic solvent phase was recovered.

  To the recovered organic solvent phase, 200 ppm of hydroquinone monomethyl ether was added, and while blowing air, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.

  When the aromatic solvent contained in the obtained polyfunctional acrylate was analyzed by gas chromatography (detection lower limit: 10 ppm), it was not detected (indicated by N.D.).

(Example 2)
Pentaerythritol 668.2 g, acrylic acid 1556.6 g, PTS 67.5 g, cupric chloride 2.7 g, and cyclohexane 405.0 g were charged into a 3 L four-necked flask equipped with a reflux tube. While blowing the same oxygen-containing gas as in Example 1, the mixture was heated and stirred at a reaction liquid temperature of 75 to 80 ° C., and dehydrated esterification reaction was carried out for 10 hours while removing generated water out of the system with a Dean-Stark tube.

  After completion of the reaction, the reaction solution was diluted by adding 1500.0 g of n-propyl acetate and 1000.0 g of cyclohexane. Further, 200 g of distilled water was added and sufficiently stirred and washed with water, and then allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed.

  Next, a 20% aqueous sodium hydroxide solution was added to the organic solvent phase to neutralize the acid component contained in the organic solvent phase, and the mixture was allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer). . The lower aqueous phase was removed and the organic solvent phase was recovered. Further, 500 g of distilled water was added to the recovered organic solvent phase, washed with water, and allowed to stand. The separated aqueous phase (lower layer) was removed, and the upper organic solvent phase was recovered.

  To the recovered organic solvent phase, 200 ppm of hydroquinone monomethyl ether was added, and while blowing air, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.

  When the obtained polyfunctional acrylic ester was analyzed by gas chromatography (detection lower limit: 10 ppm), an aromatic solvent was not detected.

(Example 3)
Dipentaerythritol 586.0, acrylic acid 1196.0 g, PTS 105.3 g, cupric chloride 2.7 g, and normal heptane 810.0 g were charged into a 3 L four-necked flask equipped with a reflux tube. The mixture was heated and stirred at a reaction liquid temperature of 95 to 100 ° C. while blowing oxygen-containing gas similar to that in Example 1.
A dehydration esterification reaction was carried out for 10 hours while removing generated water out of the system with a Dean-Stark tube.

  After completion of the reaction, 1890.0 g of methyl ethyl ketone was added to the reaction solution for dilution, and 150 g of distilled water was further added and stirred sufficiently to wash the reaction solution with water. Thereafter, the mixture was allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed.

  Next, a 20% aqueous sodium hydroxide solution was added to the organic solvent phase to neutralize the acid component contained in the organic solvent phase. The mixture was allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed to recover the organic solvent phase. Further, 450 g of distilled water was added to the recovered organic solvent phase and washed with water. The mixture was allowed to stand, the separated aqueous phase (lower layer) was removed, and the upper organic solvent phase was recovered.

  To the organic solvent phase recovered above, 200 ppm of hydroquinone monomethyl ether was added, and while blowing air, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.

  When the obtained polyfunctional acrylic ester was analyzed by gas chromatography (detection lower limit: 10 ppm), an aromatic solvent was not detected.

Example 4
In a 3 L side necked four-necked flask equipped with a reflux tube, 688.0 g of trimethylolpropane, 380.2 g of phthalic anhydride, 739.4 g of acrylic acid, 81.0 g of PTS, 1.4 g of hydroquinone monomethyl ether, 810.0 g of cyclohexane Was introduced. The mixture was heated and stirred at a reaction liquid temperature of 75 to 80 ° C. while blowing an oxygen-containing gas similar to that in Example 1. A dehydration esterification reaction was carried out for 12 hours while removing generated water out of the system with a Dean-Stark tube.

  After completion of the reaction, 1000.0 g of methyl ethyl ketone was added to the reaction solution for dilution, and a 10% aqueous sodium hydroxide solution was further added to neutralize the acid component contained in the organic solvent phase. The mixture was allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed to recover the organic solvent phase.

Next, 350 g of distilled water was added to the recovered organic solvent phase, washed with water, and allowed to stand. The separated aqueous phase (lower layer) was removed, and the upper organic solvent phase was recovered.
While blowing air into the recovered organic solvent phase, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.

  When the obtained polyfunctional acrylic ester was analyzed by gas chromatography (detection lower limit: 10 ppm), an aromatic solvent was not detected.

(Example 5)
Dipentaerythritol 518.4, methacrylic acid 1263.6 g, PTS 105.3 g, cupric chloride 2.7 g, and normal heptane 810.0 g were charged into a 3 L four-necked flask equipped with a reflux tube. The mixture was heated and stirred at a reaction liquid temperature of 95 to 100 ° C. while blowing oxygen-containing gas similar to that in Example 1.
A dehydration esterification reaction was carried out for 10 hours while removing generated water out of the system with a Dean-Stark tube.

  After completion of the reaction, 1890.0 g of methyl ethyl ketone was added to the reaction solution for dilution, and 150 g of distilled water was further added and stirred sufficiently to wash the reaction solution with water. Thereafter, the mixture was allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed.

  Next, a 20% aqueous sodium hydroxide solution was added to the organic solvent phase to neutralize the acid component contained in the organic solvent phase. The mixture was allowed to stand to separate into an aqueous phase (lower layer) and an organic solvent phase (upper layer), and the lower aqueous phase was removed to recover the organic solvent phase. Further, 450 g of distilled water was added to the recovered organic solvent phase and washed with water. The mixture was allowed to stand, the separated aqueous phase (lower layer) was removed, and the upper organic solvent phase was recovered.

To the organic solvent phase recovered above, 200 ppm of hydroquinone monomethyl ether was added, and while blowing air, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.
When the obtained polyfunctional acrylic ester was analyzed by gas chromatography (detection lower limit: 10 ppm), an aromatic solvent was not detected.

(Comparative example of the first invention)
(Comparative Example 1)
In Example 1, polyfunctional acrylic ester was obtained in the same manner as in Example 1 except that the organic solvent used in the reaction step and the washing step was changed to toluene.

  When the obtained polyfunctional acrylic ester was analyzed by gas chromatography (detection lower limit: 10 ppm), 255 ppm of toluene was detected.

(Comparative Example 2)
In Example 1, it operated similarly to Example 1 except having changed the solvent used for a washing | cleaning process into cyclohexane. In the case of this comparative example, the polyfunctional acrylate ester and cyclohexane separated into layers, and the water detergent (aqueous phase) could not be separated and removed in the washing step, so that the polyfunctional acrylate ester could not be obtained.

(Example of second invention, test example )
Hereinafter, the second aspect of the present invention will be described more specifically with reference to examples and test examples . In the following, “%” means mass%. ppm is mg / kg.

  The Hazen color number was measured visually according to JIS K-0071-1-1998 [Chemical Product Color Test Method-Part 1: Method for Measuring Hazen Unit Color Number (Platinum-Cobalt Scale)].

(Example 6)
Into a 3000 mL four-necked flask equipped with a reflux tube, 607.3 g of dipentaerythritol, 1239.5 g of acrylic acid, 40.5 g of 78% sulfuric acid, 2.7 g of hydroquinone monomethyl ether, and 810.0 g of normal heptane were added. . While blowing oxygen-containing gas (oxygen 5% by volume, nitrogen 95% by volume) into a four-necked flask while heating and stirring at a reaction liquid temperature of 95 to 100 ° C., removing generated water out of the system with a Dean-Stark tube, An 8-hour dehydration esterification reaction was performed.

  After completion of the reaction, 122.5 g of a 20% by mass aqueous sodium hydroxide solution was added to the reaction solution and stirred to neutralize part of the charged sulfuric acid (0.92 equivalent times). Thereafter, 1890.0 g of methyl ethyl ketone is added to dilute, and a 20% aqueous sodium hydroxide solution is further added 1.0 times in molar ratio to the acid content (acrylic acid) contained in the organic solvent phase and is contained in the organic solvent phase. The acid content (acrylic acid) was neutralized. Thereafter, the mixture was allowed to stand, and the aqueous phase (lower layer) and the organic phase (upper layer) were separated, and the lower aqueous phase was removed.

  Next, 450 g of a 20% aqueous sodium hydroxide solution was added to the organic phase and stirred. The mixture was allowed to stand, and the aqueous phase (lower layer) and the organic phase (upper layer) were separated, and the lower aqueous phase was removed to recover the organic phase. Further, 450 g of distilled water was added to the recovered organic phase and washed with water. The aqueous phase (lower layer) separated by standing was removed, and the upper organic phase was recovered.

To the recovered organic phase, 200 ppm of hydroquinone monomethyl ether was added, and while blowing air, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.
The Hazen color number of the obtained polyfunctional acrylic ester was 60. Moreover, when the polyfunctional acrylic ester was analyzed by gas chromatography (detection lower limit: 10 ppm), an aromatic solvent was not detected.

(Example 7)
In a 3000 mL four-necked flask equipped with a reflux tube, a pentaerythritol 668.2 g, acrylic acid 1556.6 g, paratoluenesulfonic acid monohydrate (hereinafter referred to as PTS) 67.5 g, cupric chloride 2 0.7 g and cyclohexane 405.0 g were added. The mixture was heated and stirred at a reaction liquid temperature of 75 to 80 ° C. while blowing an oxygen-containing gas similar to that in Example 6. A dehydration esterification reaction was carried out for 10 hours while water generated with the progress of the reaction was removed from the system with a Dean-Stark tube.

  After completion of the reaction, 777.0 g of a 20% by mass aqueous sodium hydroxide solution (10.9 equivalent times with respect to the charged paratoluenesulfonic acid) was added to the obtained reaction solution and neutralized by stirring, and then methyl ethyl ketone 1500 0.0 g and 1000.0 g of cyclohexane were added to dilute the reaction solution. The mixture was allowed to stand to separate the aqueous phase (lower layer) and the organic phase (upper layer), and the lower aqueous phase was removed.

  Next, 500 g of a 20% by mass aqueous sodium hydroxide solution was added to the organic phase and stirred, and then allowed to stand. The aqueous phase (lower layer) and the organic phase (upper layer) were separated, and the lower aqueous phase was removed to recover the organic phase. Further, 500 g of distilled water was added to the recovered organic phase and washed with water. The mixture was allowed to stand, the separated aqueous phase (lower layer) was removed, and the upper organic phase was recovered.

To the recovered organic phase, 200 ppm of hydroquinone monomethyl ether was added, and while blowing air, the solvent was distilled off by heating to 80 ° C. under reduced pressure to obtain a polyfunctional acrylic ester.
The Hazen color number of the obtained polyfunctional acrylic ester was 40. When the polyfunctional acrylate obtained by gas chromatography (detection lower limit: 10 ppm) was analyzed, no aromatic solvent was detected.

(Example 8)
In Example 6, after completion of the reaction, 92.1 g of a 20% by mass aqueous sodium hydroxide solution was added to the reaction solution and stirred, and after neutralizing a part of the charged sulfuric acid (0.70 equivalent times), methyl ethyl ketone was used. A polyfunctional acrylic acid ester was obtained in the same manner as in Example 6 except that the reaction solution was diluted and then 20% by mass sodium hydroxide was added.
The Hazen color number of the obtained polyfunctional acrylic ester was 60. Moreover, when the obtained polyfunctional acrylic ester was analyzed using the gas chromatography (detection lower limit: 10 ppm), the aromatic solvent was not detected.

(Test Example 1)
In Example 6, the reaction solution was diluted with methyl ethyl ketone without neutralizing the sulfuric acid that is an acid catalyst in advance, and then 20% sodium hydroxide was added. A functional acrylic ester was obtained.
The Hazen color number of the obtained polyfunctional acrylic ester was 90. Moreover, when the obtained polyfunctional acrylic ester was analyzed using gas chromatography (detection limit: 10 ppm), the aromatic solvent was not detected.

(Test Example 2)
In Example 7, the reaction solution was diluted with methyl ethyl ketone without previously neutralizing sulfuric acid as an acid catalyst, and then the same operation as in Example 7 was performed except that a 20 mass% aqueous sodium hydroxide solution was added. A polyfunctional acrylic ester was obtained.
The Hazen color number of the obtained polyfunctional acrylic ester was 150. Moreover, when the obtained polyfunctional acrylic ester was analyzed using gas chromatography (detection limit: 10 ppm), the aromatic solvent was not detected.

(Test Example 3)
In Example 6, after completion of the reaction, 39.5 g of a 20% by mass aqueous sodium hydroxide solution was added to the reaction solution and stirred. After neutralizing a part of the charged sulfuric acid (0.30 equivalent times), methyl ethyl ketone was used. A polyfunctional acrylic acid ester was obtained in the same manner as in Example 6 except that the reaction solution was diluted and then 20% by mass sodium hydroxide was added.

  The Hazen color number of the obtained polyfunctional acrylic ester was 80. Moreover, when the obtained polyfunctional acrylic ester was analyzed using the gas chromatography (detection lower limit: 10 ppm), the aromatic solvent was not detected.

  According to the method for producing a (meth) acrylic acid ester of the present invention, an aromatic hydrocarbon compound is not used as an organic solvent in the esterification reaction and the washing step. As a result, it is possible to obtain a (meth) acrylic acid ester that is less affected by humans and the environment due to aromatic hydrocarbon compounds, and less colored (meth) acrylic acid ester. Can be obtained.

Claims (8)

(1) An aliphatic hydrocarbon compound and / or an alicyclic hydrocarbon compound having 6 to 12 carbon atoms and a boiling point of 40 to 160 ° C. at normal pressure is used as a reaction solvent in the presence of an acid catalyst ( An esterification reaction step in which a reaction liquid containing a polyfunctional (meth) acrylic acid ester is obtained by an esterification reaction of (meth) acrylic acid and a polyhydric alcohol;
(2) The dilution treatment step of adding an organic solvent composed of at least a ketone compound and / or an ester compound and the neutralization treatment step of adding an alkaline aqueous solution to the reaction solution obtained in the esterification reaction step in any order or A dilution / neutralization treatment step to obtain a dilution / neutralization treatment solution by carrying out simultaneously
(3) An organic phase recovery step of obtaining an organic phase by separating the diluted / neutralized treatment solution obtained in the dilution / neutralization step into an aqueous phase and an organic phase;
(4) a water washing step of washing the recovered organic phase with water;
(5) A polyfunctional (meth) acrylic acid obtained by separating the polyfunctional (meth) acrylic acid ester from the organic solvent by distilling off the organic solvent from the washed organic phase. An ester isolation step;
The manufacturing method of the polyfunctional (meth) acrylic acid ester which has this.   Before the neutralization treatment step, the preliminary washing step of removing the acid catalyst by washing the reaction solution obtained in the esterification reaction step or the dilution solution obtained in the dilution treatment step of the dilution / neutralization treatment step with a water detergent. Furthermore, the manufacturing method of the polyfunctional (meth) acrylic acid ester of Claim 1 which has.   3. The polyfunctional (meta ) A method for producing acrylic ester.   The polyfunctional (meth) acrylic acid ester according to any one of claims 1 to 3, wherein the ketone compound and / or the ester compound is a compound having 3 to 8 carbon atoms and a boiling point of 40 to 160 ° C at normal pressure. Manufacturing method. (1) An aliphatic hydrocarbon compound and / or an alicyclic hydrocarbon compound having 6 to 12 carbon atoms and a boiling point of 40 to 160 ° C. at normal pressure is used as a reaction solvent in the presence of an acid catalyst ( An esterification reaction step in which a reaction liquid containing a polyfunctional (meth) acrylic acid ester is obtained by an esterification reaction of (meth) acrylic acid and a polyhydric alcohol;
(6) An acid catalyst neutralization step for obtaining an acid catalyst neutralization reaction liquid by adding at least 1/2 equivalent of an alkali component to the prepared acid catalyst in the obtained reaction liquid;
(7) A solvent comprising a ketone compound is added to the acid catalyst neutralization reaction solution to dilute the acid catalyst neutralization reaction solution, and alkali water is added to neutralize unreacted (meth) acrylic acid. A dilution / neutralization step to obtain a reaction mixture;
(8) An organic phase recovery step of separating the diluted / neutralized liquid obtained in the dilution / neutralization step into an organic phase and an aqueous phase, and recovering the organic phase;
(9) a water washing step of washing the recovered organic phase with water;
(10) separating the polyfunctional (meth) acrylic acid ester from the organic solvent by distilling off the organic solvent from the washed organic phase, and isolating the polyfunctional (meth) acrylic acid ester;
The manufacturing method of the polyfunctional (meth) acrylic acid ester which has this.   The method for producing a polyfunctional (meth) acrylic acid ester according to claim 5, further comprising a preliminary water washing step of washing the reaction solution with a water detergent before performing the acid catalyst neutralization step. The aliphatic hydrocarbon compound and / or alicyclic hydrocarbon compound having 6 to 12 carbon atoms and having a boiling point of 40 to 160 ° C. at normal pressure is selected from n-hexane, cyclohexane, methylcyclohexane, n-heptane and isooctane. The method for producing a polyfunctional (meth) acrylic acid ester according to claim 5, wherein the polyfunctional (meth) acrylic acid ester is one or more kinds. The method for producing a polyfunctional (meth) acrylic acid ester according to any one of claims 5 to 7, wherein the ketone compound is a compound having 3 to 8 carbon atoms and a boiling point of 40 to 160 ° C at normal pressure.