JP2008308466A - Method for producing (meth)acrylic ester - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing an acrylic or a methacrylic ester by which the storage stability and heat stability of the resultant acrylic or the methacrylic ester can be improved and more specifically, a rise in acid value can be suppressed by a simple method. <P>SOLUTION: The method for producing the acrylic or the methacrylic ester comprises subjecting acrylic acid or methacrylic acid to a dehydration esterification reaction in the presence of an acid catalyst, passing the resultant reaction liquid through a neutralization treatment and a water washing treatment and then adding a carbazide to the obtained reaction liquid. In the method for production, the dehydration esterification reaction is preferably carried out in an organic solvent. The reaction liquid is more preferably desolvated after adding the carbazide to the reaction liquid. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a method for producing a (meth) acrylic acid ester, and belongs to the technical field of a method for producing a (meth) acrylic acid ester.

  Since (meth) acrylic acid esters are cured by ultraviolet irradiation or electron beam irradiation, they are used in various industrial applications such as optical lenses, printing inks, coating agents, and adhesives as compounding components of photocurable compositions. .

However, if the storage stability and thermal stability of the (meth) acrylic acid ester are poor, problems may occur.
For example, if the storage stability of (meth) acrylic acid ester is poor, a polymerization reaction will occur during storage, resulting in a polymer component, or (meth) acrylic acid ester will decompose and acid such as (meth) acrylic acid May generate minutes.
The composition of (meth) acrylic acid ester containing a polymer component causes uneven curing and turbidity, and therefore cannot be suitably used for optical lens applications where uniformity and light transmittance are important.
In addition, acid-generated (meth) acrylic acid ester deteriorates water resistance in addition to problems of odor and device corrosion. Therefore, when used for coating agents and adhesives, the cured product absorbs moisture. As a result, the coating surface may be peeled off or the adhesive strength may be reduced.
In addition, (meth) acrylic acid esters may be heated and stirred for homogenization at the time of blending or exposed to a heat resistance test after photocuring, but (meth) acrylic acid esters with poor thermal stability are described above. In addition to the generation of such polymer and acid components, it cannot be used for optical lens applications where transparency is essential in order to produce coloring.
In the present specification, acrylic acid and methacrylic acid are collectively referred to as “(meth) acrylic acid”.

One of the causes of poor storage stability and thermal stability of (meth) acrylic acid esters is the effect of impurities remaining in the product.
(Meth) acrylic acid esters are usually produced by dehydrating esterification reaction of (meth) acrylic acid and alcohols in the presence of an acid catalyst, but various impurities are by-produced during the esterification reaction. In order to remove such impurities, the reaction solution after dehydration esterification is usually washed with water or an aqueous alkaline solution, but the removal of impurities is not always sufficient.

For this reason, various methods for strengthening the washing process during the production of (meth) acrylic acid esters have been studied.
For example, Patent Document 1 discloses a method in which a reaction product after dehydration esterification is neutralized and then further treated with amines.
However, according to this method, after treating the reaction product with amines, in order to remove the amines from the reaction product, the reaction product must be subsequently washed with an acidic aqueous solution. May contain acidic components. Therefore, in this method, after washing with an aqueous alkaline solution after washing with an acidic aqueous solution, washing with soft water is repeated three times, and the process is complicated and requires a long time, so the productivity is reduced. It is remarkable. Also, if the treatment is carried out industrially, a cleaning tank made of a special and expensive material that does not corrode both the alkaline aqueous solution and the acidic aqueous solution is used, or the treatment with the alkaline aqueous solution and the treatment with the acidic aqueous solution are separately performed. It is difficult to say that it is suitable for industrial implementation.

Patent Document 2 discloses a method of adding a cationic surfactant when neutralizing or washing a reaction solution after producing (meth) acrylic acid ester. According to this method, It is disclosed that emulsification near the interface between the organic layer and the aqueous layer can be prevented, the separation time of the organic layer and the aqueous layer can be shortened, and as a result, impurities can be efficiently removed.
However, although the method described in Patent Document 2 is excellent in shortening the separation time of the organic layer and the aqueous layer, the storage stability and thermal stability of the obtained (meth) acrylic acid ester are insufficient.

JP-A-6-219991 (Claims) JP 2001-048831 A (Claims)

As a result of various studies to solve the above problems, the present inventors have added a specific phase transfer catalyst and an aqueous solution of an alkali metal hydroxide in the neutralization step of the esterification reaction solution, and heat treatment is performed. The manufacturing method of the (meth) acrylic ester to perform is discovered (patent document 3).
Invention of patent document 3 is a manufacturing method which can solve the said subject and can improve the storage stability and thermal stability of (meth) acrylic acid ester, but the point which heat-processes in a neutralization process is somewhat. It was complicated.
The present inventors can improve the storage stability and thermal stability of the resulting (meth) acrylic acid ester by a simpler method, and more specifically, can suppress an increase in acid value ( He intensively studied to find out a method for producing a (meth) acrylic acid ester.

Japanese Patent Application No. 2005-336369 (Claims)

While the inventions described in Patent Documents 1 to 3 were made based on the idea of removing impurities that cause storage stability and thermal stability from (meth) acrylic acid esters, the present inventors As a result of various investigations based on the idea that the above problems can be solved by a simpler method if impurities in (meth) acrylic acid ester are deactivated, The storage stability and thermal stability of the (meth) acrylic acid ester product are remarkably improved by performing a simple means of adding a specific treating agent to the reaction solution obtained after the sum treatment and the water washing treatment. As a result, the present invention has been completed.
Hereinafter, the present invention will be described in detail.

  The (meth) acrylic acid ester obtained by the production method of the present invention improves the storage stability and thermal stability of the resulting (meth) acrylic acid ester by a simple method of adding a specific treating agent. More specifically, an increase in acid value can be suppressed. For this reason, the obtained (meth) acrylic acid ester can be suitably used for various industrial uses such as optical lenses, printing inks, coating agents, and adhesives as a compounding component of the photocurable composition.

1. Esterification Reaction In the present invention, first, (meth) acrylic acid and alcohol are heated and stirred in the presence of an acid catalyst to perform a dehydration esterification reaction.
As the alcohol in this case, various compounds can be used, and specific examples include the alcohols shown below.
[1] Methanol, ethanol, n-propyl alcohol, isopropyl alcohol, n-butyl alcohol, isobutyl alcohol, n-pentyl alcohol, cyclohexanol, n-heptyl alcohol, n-octyl alcohol, 2-ethylhexyl alcohol, isooctyl alcohol, monohydric alkyl alcohols such as n-nonyl alcohol and isononyl alcohol, and alkylene oxide adducts thereof;
[2] Compounds having phenolic hydroxyl groups such as phenol, chlorophenol, bromophenol, fluorophenol, naphthol, phenylphenol, cumylphenol, nonylphenol, bisphenol A, bisphenol F, thiobisphenol and 4,4′-sulfonyldiphenol An alkylene oxide adduct.
[3] Glycols such as ethylene glycol, propylene glycol, neopentyl glycol, diethylene glycol, triethylene glycol, polyethylene glycol, dipropylene glycol, tripropylene glycol, polypropylene glycol, and alkylene oxide adducts thereof.
[4] Glycerin such as glycerin, diglycerin, triglycerin, polyglycerin and their alkylene oxide adducts.
[5] Polyols such as butanediol, pentanediol, hexanediol, trimethylolpropane, ditrimethylolpropane, pentaerythritol, dipentaerythritol, and their alkylene oxide adducts
[6] Tris-2-hydroxyethyl isocyanurate Examples of the alkylene oxide include ethylene oxide and propylene oxide.
The average number of moles of alkylene oxide added per mole of compound is preferably 1 to 10 moles.

The present invention can be preferably applied to polyhydric alcohols that are likely to generate many impurities in the resulting (meth) acrylic acid ester, among the above-described alcohols.
Furthermore, among the polyhydric alcohols, the above-described polyols and polyhydric alcohol adducts with alkylene oxide, which are more likely to generate more impurities in the resulting (meth) acrylic acid ester, can be preferably applied. Preferable specific examples of the alkylene oxide-attached polyhydric alcohol include a propylene oxide adduct of trimethylolpropane, an ethylene oxide adduct of bispheol A, and an ethylene oxide adduct of diglycerin.

  The proportion of (meth) acrylic acid and alcohol used in the dehydration esterification reaction is preferably 0.8 to 2.0 moles, more preferably 1.0 to (meth) acrylic acid per mole of hydroxyl group of alcohol. 1.5 moles. By making this ratio 0.8 mol or more, the reaction time of dehydration esterification can be shortened, and side reactions such as Michael addition of alcoholic hydroxyl groups to (meth) acryloyl groups of (meth) acrylic acid esters are suppressed. Therefore, it is preferable because the product purity can be improved. On the other hand, by controlling the amount to 2.0 mol or less, it is possible to improve the product purity by suppressing side reactions such as Michael addition of (meth) acrylic acid to the (meth) acryloyl group of (meth) acrylic acid ester. In addition, the operation of removing unreacted acrylic acid after dehydration esterification can be simplified, which is preferable.

Examples of the acid catalyst used in the dehydration esterification reaction include p-toluenesulfonic acid, methanesulfonic acid, trifluoromethanesulfonic acid, sulfuric acid, and the like, and these can be used alone or in any combination of two or more.
The usage ratio of the acid catalyst is preferably 0.05 mol% to 10 mol%, more preferably 0.5 to 5 mol%, based on the number of moles of the alcoholic hydroxyl group subjected to dehydration esterification. By making this proportion 0.05 mol% or more, the practical reaction rate can be made sufficient, which is preferable. On the other hand, the content of 10 mol% or less is preferable because side reactions can be suppressed to improve product purity, coloration can be suppressed, and catalyst removal and product decolorization operations can be simplified in the purification process.

In the present invention, it is preferable to use an organic solvent having low solubility with water produced by the dehydration esterification reaction, while azeotropically distilling off the water. Preferred organic solvents include, for example, aromatic hydrocarbons such as toluene, benzene and xylene, aliphatic hydrocarbons such as hexane, cyclohexane and heptane, and ketones such as methyl ethyl ketone and cyclohexanone.
In consideration of the solubility of the substrate, the organic solvent may be used alone or in combination of two or more.
The proportion of the organic solvent is preferably 30 to 70% by weight in the reaction solution.

  As esterification reaction temperature, 70-140 degreeC is preferable. A reaction temperature of 70 ° C. or higher is preferable because the reaction rate is excellent, and a temperature of 140 ° C. or lower is preferable because the amount of impurities by-products during esterification is suppressed and gelation does not occur.

In the dehydration esterification reaction, it is preferable to use a polymerization inhibitor for the purpose of preventing polymerization of the (meth) acryloyl group, and oxygen-containing gas may be introduced into the reaction solution. Examples of the polymerization inhibitor include hydroquinone, tert-butyl hydroquinone, hydroquinone monomethyl ether, 2,6-di-tert-butyl-4-methylphenol, 2,4,6-tri-tert-butylphenol, benzoquinone, phenothiazine and the like. Organic polymerization inhibitors, inorganic polymerization inhibitors such as copper chloride and copper sulfate, and organic salt polymerization inhibitors such as copper dibutyldithiocarbamate. A polymerization inhibitor may be used individually by 1 type, or may be used in combination of 2 or more types arbitrarily. As a ratio of a polymerization inhibitor, 5-20,000 wtppm is preferable in a reaction liquid, More preferably, it is 25-3,000 wtppm.
Examples of the oxygen-containing gas include air, a mixed gas of oxygen and nitrogen, a mixed gas of oxygen and helium, and the like.

2. Neutralization treatment and water washing treatment In the present invention, neutralization treatment and water washing treatment are performed on the reaction solution after dehydration esterification. Hereinafter, each method will be described.

2-1. Neutralization Treatment The neutralization treatment is performed for the purpose of removing acidic components such as unreacted (meth) acrylic acid and acidic catalyst in the reaction product liquid, and is usually performed by bringing the reaction liquid into contact with an alkaline aqueous solution.
The neutralization treatment may be performed according to a conventional method, and examples thereof include a method of adding an alkaline aqueous solution to the reaction solution, stirring and mixing.

Examples of the alkali component include lithium metal, alkali metal salts such as sodium hydroxide and potassium hydroxide, and ammonia. As an alkali component, 1 type may be used independently or 2 or more types may be used in arbitrary combinations. Of these, sodium hydroxide is preferred because of its excellent effect, low cost, and easy availability.
In this case, the amount of the alkali component is usually 1 time or more, preferably 1.1 to 2.0 times in molar ratio to the acid content of the reaction solution. If this addition amount is less than 1 time in molar ratio with respect to the acid content of the reaction solution, neutralization of the acid content becomes insufficient, such being undesirable. Moreover, it is preferable that the density | concentration of aqueous alkali solution is 1 to 25 weight%, More preferably, it is 10 to 25 weight%. By setting this concentration to 1% by weight or more, the amount of waste water after neutralization can be suppressed, and it is preferable to set it to 25% by weight or less because there is no polymerization of (meth) acrylic acid ester.

  The stirring and mixing time may be appropriately set according to the amount of the reaction solution, the amount of the acidic component contained therein, the purpose, and the like, but is preferably about 5 to 120 minutes.

2-2. Washing treatment In the present invention, the above-described esterification reaction solution or neutralization treatment solution is washed with water. The point at which the water washing treatment is performed can be appropriately selected according to the components used and the purpose. Moreover, you may perform the water washing process in multiple times.
What is necessary is just to perform a washing process according to a conventional method. Specifically, a method of adding water or an inorganic aqueous solution to the reaction solution obtained by the esterification reaction or the neutralization treatment solution, stirring and mixing, and the like can be mentioned.
In the washing step, water is usually used. On the other hand, when the separation from the organic layer is improved or a high-purity product is required, an inorganic aqueous solution is preferably used. Specifically, an aqueous ammonium salt solution such as an aqueous ammonium sulfate solution and an aqueous ammonium chloride solution, Examples include aqueous sodium salt solutions such as sodium chloride, and acidic water such as aqueous hydrochloric acid.

2-3. In addition, in the said neutralization process or / and a water washing process, it can heat as needed.
The heating temperature is preferably 30 to 80 ° C., and the heating time is preferably 5 minutes to 5 hours.
It is.
In the case of heating, a polymerization inhibitor is preferably used for the purpose of preventing polymerization of the (meth) acryloyl group, and oxygen-containing gas may be further introduced into the reaction solution.
As a polymerization inhibitor, the same thing as the above is mentioned, The ratio is also the same as the above.
Examples of the oxygen-containing gas include the same as described above.

3. Treatment with carbazide
3-1. Carbazide In the present invention, carbazide (hereinafter sometimes referred to as “treatment agent”) is added to the reaction solution obtained after the neutralization treatment and the water washing treatment.

As the carbazide used in the present invention, various compounds can be used as long as they are compounds having a carbazide group.
The carbazide is preferably a compound represented by the general formula (1) R ¹ R ² NNHCONHNR ³ R ⁴ .
In General formula (1), R < ¹ > -R < ⁴ > shows a hydrogen atom, the alkyl group which may be substituted, or the aryl group which may be substituted each independently.
R ¹ and R ² or R ³ and R ⁴ may each be a group that forms a ring by bonding. R ¹ and R ³ , R ¹ and R ⁴ , R ² and R ^3, or R ² and R ⁴ may be a group that forms a ring by bonding. In addition, since these groups which form a ring are synonymous with each other, in the following, R ¹ and R ³ will be described as a representative group which forms a ring by bonding.

Examples of the alkyl group include a methyl group, an ethyl group, a propyl group, and a butyl group.
Examples of the aryl group include a phenyl group, a toluyl group, a t-butylphenyl group, a nitrophenyl group, and a dinitrophenyl group.

As a group which forms a ring by combining R ¹ and R ² or R ³ and R ^4, an alkylene group having 4 to 7 carbon atoms, — (CH ₂ ) _m S (CH ₂ ) _n — (m, n integer of 1 to 5 where, m + n = 3~6 _{integer), -. (CH 2)} m O (CH 2) n -. (m, n integer of 1 to 5 where, m + n = 3~ An integer of 6).

Examples of the group that forms a ring by bonding R ¹ and R ³ include an alkylene group having 1 to 3 carbon atoms, —CH ₂ SCH ₂ —, and —CH ₂ OCH ₂ —.

Specifically, the carbazide represented by the general formula (1) specifically corresponds to the corresponding diisocyanate, urea derivative, NH ₂ NR ¹ R ² , and NH ₂ NR ³ R ⁴ (R ^{1 to} R ⁴ are as defined above). Obtained by a condensation reaction with a hydrazine compound represented by

  Specific examples of carbazide include the following compounds.

Among these, compounds having excellent solubility in (meth) acrylic acid esters and large basicity are preferable. Specifically, R ¹ and R ² and R ³ and R ⁴ are compounds having 4 to 6 carbon atoms, R ¹ has a dinitrophenyl group, and R ^{2 to} R ⁴ are all hydrogen atoms. Compounds are preferred.

  Carbazide may be used alone or in combination of two or more.

3-2. Method for adding treatment agent The timing of addition of the treatment agent is arbitrary as long as it is a reaction solution obtained after neutralization treatment and water washing treatment. Specifically, filtration is performed before and after the solvent removal step. When performing, before and after the filtration step, and further the final product.
Among these, since the method of adding the treatment agent before the desolubilization step can be performed in one step in combination with the solvent removal step and the addition step of the treatment agent, the addition step of the treatment agent can be omitted. preferable.
Examples of the method for adding the treating agent include a method of adding to the (meth) acrylic acid ester while stirring and mixing.
The addition ratio of the treatment agent is preferably 2 to 10,000 wtppm and more preferably 5 to 3000 wtppm with respect to the (meth) acrylic acid ester. When this value is 2 wtppm or more, the effect of the treatment agent can be effectively exhibited. On the other hand, when it is 10,000 wtppm or less, it is excellent in solubility in the obtained (meth) acrylate and used as a composition. In this case, the compatibility with other components is also excellent.

The treatment agent can be added at room temperature, but can be heated as necessary.
In particular, when a polyhydric alcohol is used as the alcohol, heating is preferable. This is because when the polyhydric alcohol is used as the alcohol, the (meth) acrylic ester obtained becomes a high-viscosity product, and the treatment agent can be blended uniformly in a short time.
The heating temperature and the heating time may be appropriately set according to the (meth) acrylic acid ester to be obtained and the purpose, but the heating temperature is preferably 30 to 100 ° C, more preferably 30 to 80 ° C. The time is preferably 5 minutes to 5 hours, more preferably 30 minutes to 3 hours.
In the case of heating, a polymerization inhibitor is preferably used for the purpose of preventing polymerization of the (meth) acryloyl group, and oxygen-containing gas may be further introduced into the reaction solution.
As a polymerization inhibitor, the same thing as the above is mentioned, The ratio is also the same as the above.
Examples of the oxygen-containing gas include the same as described above.

The solvent removal process will be described. The neutralization treatment liquid or the water washing treatment liquid is transferred to the solvent removal tank, and the organic solvent in the organic layer after the aqueous layer is separated by the neutralization treatment or the water washing treatment is removed.
The solvent removal treatment may be performed in accordance with a conventional method, for example, a method of removing the organic solvent by heating the solvent removal tank under reduced pressure.
What is necessary is just to set suitably as a pressure reduction 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.
Although heating temperature should just be suitably set according to the (meth) acrylic acid ester obtained, a pressure reduction degree, and the objective, 40-100 degreeC is preferable, More preferably, it is 60-80 degreeC. In order to suppress thermal polymerization of the (meth) acrylic acid ester, it is preferable to maintain the temperature at 80 ° C. or lower.
In the solvent removal step, it is preferable to supply oxygen or add a polymerization inhibitor in order to suppress thermal polymerization of the (meth) acrylic acid ester. As a polymerization inhibitor, the same thing as the above is mentioned, The ratio is also the same as the above.

  As described above, it is preferable to add a treating agent before the solvent removal step and then remove the solvent by heating under reduced pressure. Thereby, while mixing a processing agent in (meth) acrylic acid ester, an organic solvent can be removed and the addition process of a processing agent can be skipped.

If further product quality is required, further filtration can be performed after the solvent removal step.
The filtration step may be performed in accordance with a conventional method, and pressure filtration is preferable.
Examples of the pressure filtration method include a method in which the reaction liquid after solvent removal is put into a filter equipped with filter paper or filter cloth, and filtration is performed while pressure is applied to the filter. In this case, a method of adding a filter aid to the reaction solution after solvent removal, a method of pre-coating a filter aid on the surface of filter paper or filter cloth, and a method of using these in combination are preferable because the filtration efficiency can be improved. Examples of the gas used for pressurization include nitrogen, oxygen-containing gas (oxygen 5% by volume, nitrogen 95% by volume), and air.

As the production method of the present invention, among the above-mentioned methods, the following method (1) or (2) is preferable. (1) A step of adding a treatment agent to the reaction liquid after neutralization treatment and washing treatment, and a treatment agent. A method comprising a step of removing an organic solvent from an added reaction solution.
(2) A method comprising a step of removing the organic solvent from the reaction after the neutralization treatment and the water washing treatment, a step of adding the treatment agent to the product excluding the organic solvent, and a step of heating the product to which the treatment agent has been added.

The method (1) is preferable because the solvent removal step and the treatment agent addition step can be performed in one step, and the treatment agent addition step can be omitted.
In addition, when the (meth) acrylic ester finally obtained has high viscosity or the solubility of the treatment agent is insufficient, the treatment agent can be dissolved or dispersed by adding the treatment agent to the final product. It may be insufficient. According to this method, even when the (meth) acrylic ester finally obtained has a high viscosity, the treatment agent is added in a low-viscosity state containing an organic solvent, so that the treatment agent has excellent solubility or dispersibility. It is preferable at the point which becomes a thing.

  According to the method (2), in the case of a (meth) acrylic acid ester having a high viscosity as compared with the case where the treatment agent is simply added, the viscosity is reduced by heating to improve the mixing property of the treatment agent. Can do.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples. In the following description, “parts” means “parts by weight”.

[Various analysis methods]
○ Acid Value According to JIS K-0070-1992, the obtained acrylic ester was dissolved in ethanol, and titrated with potassium hydroxide solution using phenolphthalein as an indicator. The acid value of the sample was calculated from the following formula.
Acid value [mg-KOH / g] = N × T × f × 56.11 / W
N: concentration of alcoholic potassium hydroxide solution [mol / L]
T: titration of alcoholic potassium hydroxide solution [ml]
f: titer of alcoholic potassium hydroxide solution W: sample weight [g]

O Forced deterioration test 5 g of the acrylic acid ester obtained in a 30 ml glass container was placed and left for several days in an air-cooled dark place to adjust the water concentration contained in the acrylic acid ester to 1000 to 3000 wtppm.
Thereafter, the glass container containing the acrylic ester was sealed and heated in a heating block maintained at 80 ° C. for 144 hours. After cooling, the acid value was measured by the method described above.

○ Example 1
In a 500 mL four-necked flask with a side tube equipped with a reflux tube, 175 g of bisphenol A ethylene oxide 4 mol adduct, 75 g of acrylic acid, 174 g of toluene, 10.5 g of paratoluenesulfonic acid monohydrate (hereinafter referred to as TS) Hydroquinone (hereinafter referred to as HQ) 0.26 g and cupric chloride 0.26 g were charged. While blowing oxygen-containing gas (oxygen 5% by volume, nitrogen 95% by volume, the same shall apply hereinafter) at a reaction liquid temperature of 100 to 118 ° C., the generated water was removed from the system with a Dean-Stark tube for 7 hours. A dehydration esterification reaction was performed.
After completion of the reaction, the reaction solution is cooled to 40 ° C. or less, and after toluene and water are added and washed by washing, a 20 wt% aqueous sodium hydroxide solution is added to neutralize, and water is further added. Extraction washing was performed.

The obtained organic layer is in a state where the target acrylic ester is diluted with toluene and a small amount of water, and the washing operation is substantially completed. To this was added 0.07 g of hydroquinone monomethyl ether (hereinafter referred to as MQ) and 400 wtppm of compound A with respect to the acrylate ester, and the mixture was heated to 60-80 ° C. under reduced pressure while blowing oxygen-containing gas. Left.
The reaction solution after removing the solvent was filtered under pressure to obtain an acrylate ester.

  The acid value of the resulting acrylic acid ester was measured. Furthermore, in order to evaluate the storage stability and the heat stability, a forced deterioration test was performed, and then the acid value was measured. The results are shown in Table 1.

Example 2
In Example 1, the solvent removal treatment was performed without adding Compound A.
Compound A was added to the crude product obtained after the toluene was distilled off at the same rate as in Example 1, and the mixture was stirred at 70 ° C. for 1 hour for uniform mixing. Thereafter, after filtration under pressure, an acrylic acid ester was obtained. Table 1 shows the acid values before and after the forced deterioration test.

Example 3
In Example 1, instead of Compound A, Compound B was added in an amount of 450 wtppm with respect to the acrylate ester, and the same operation was performed to obtain an acrylate ester. Table 1 shows the acid values before and after the forced deterioration test.

○ Comparative Example 1
In Example 1, the solvent removal treatment was performed without adding Compound A.
The reaction solution after removing the solvent was filtered under pressure to obtain an acrylate ester. The acid value was measured about the obtained acrylic acid ester, and the acid value was measured after the forced deterioration test. The results are shown in Table 1.

Example 4
Into a flask similar to that in Example 1, 186 g of a propylene oxide 6 mol adduct of trimethylolpropane, 100 g of acrylic acid, 147 g of toluene, 9.5 g of PTS, 0.45 g of HQ and 0.45 g of cupric chloride were added, and an oxygen-containing gas was added. The mixture was heated and stirred within the range of the reaction solution temperature of 80 to 110 ° C. and the reaction system pressure of 400 to 650 mmHg. A dehydration esterification reaction was carried out for 7 hours while removing generated water out of the system with a Dean-Stark tube.
After completion of the reaction, the reaction solution was neutralized by the same method as in Example 1, and water was further added to perform extraction washing. Thereafter, the same operation as in Example 1 was performed to obtain an acrylate ester to which Compound A was added. Table 2 shows the acid values before and after the forced deterioration test.

○ Comparative Example 2
In Example 4, the solvent removal treatment was performed without adding Compound A.
The reaction solution after removing the solvent was filtered under pressure to obtain an acrylate ester. The acid value was measured about the obtained acrylic acid ester, and the acid value was measured after the forced deterioration test. The results are shown in Table 2.

Example 5
Into the same flask as in Example 1, 76.3 g of dipentaerythritol, 190 g of acrylic acid, 158 g of toluene, 4.0 g of sulfuric acid, 0.51 g of MQ, and 0.51 g of HQ were added, and the reaction solution temperature was 80 to 80% while blowing oxygen-containing gas. The mixture was heated and stirred at 110 ° C. and a reaction system pressure of 400 to 760 mmHg. A dehydration esterification reaction was carried out for 5 hours while removing generated water out of the system with a Dean-Stark tube.
After completion of the reaction, the reaction solution was neutralized by the same method as in Example 1, and water was further added to perform extraction washing. Thereafter, the same operation as in Example 1 was performed to obtain an acrylate ester to which Compound A was added. Table 3 shows the acid values before and after the forced deterioration test.

○ Comparative Example 3
In Example 5, the solvent removal treatment was performed without adding Compound A.
The reaction solution after removing the solvent was filtered under pressure to obtain an acrylate ester. The acid value was measured about the obtained acrylic acid ester, and the acid value was measured after the forced deterioration test. The results are shown in Table 3.

The manufacturing method of this invention can be utilized for the manufacturing method of (meth) acrylic acid ester.
Furthermore, the obtained (meth) acrylic acid ester can be suitably used for various industrial uses such as an optical lens, a printing ink, a coating agent, and an adhesive as a compounding component of the photocurable composition.

Claims (5)

(Meth) acrylic acid and alcohol are subjected to a dehydration esterification reaction in the presence of an acid catalyst, and the resulting reaction solution is subjected to neutralization treatment and water washing treatment, and carbazide is added to the reaction solution obtained. Ester production method. The method for producing a (meth) acrylic acid ester according to claim 1, wherein the alcohol is a polyhydric alcohol. The method for producing a (meth) acrylic acid ester according to claim 1 or 2, wherein carbazide is added to and mixed with the reaction solution at 30 to 100 ° C. The method for producing a (meth) acrylic acid ester according to any one of claims 1 to 3, wherein the dehydration esterification reaction is performed in an organic solvent. The method for producing a (meth) acrylic acid ester according to claim 4, wherein the solvent is removed after adding carbazide to the reaction solution.