JPH08319256A - Production of pentaerythritol partial (meth)acrylates - Google Patents

Abstract

PURPOSE: To readily produce the subject high-purity esters which are a liquid and each contain a large amount of partial ester derivative such as a triester derivative in high yields by reacting specific (meth)acrylic esters with aliphatic alcohols. CONSTITUTION: The transesterification of (B) pentaerythritol (meth)acrylates consisting essentially of (A) pentaerythritol tetra(meth)acrylate with (C) aliphatic alcohols (preferably a 1-4C aliphatic alcohol, especially methanol) is carried out in the presence of (D) a catalyst (preferably an alkali metallic hydroxide, especially potassium hydroxide). Furthermore, the content of the component (A) in the component (B) is preferably 40-100 pts.wt. based on 100 pts.wt. total amount of the component (A).

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing pentaerythritol partial (meth) acrylic esters, more specifically pentaerythritol tri (meth) acrylic ester, pentaerythritol di (meth) acrylic ester, pentaerythritol. The present invention relates to a method for producing a pentaerythritol partial (meth) acrylic ester which contains a large amount of a partial ester such as mono (meth) acrylic ester and is liquid at room temperature.

[0002]

2. Description of the Related Art Pentaerythritol (meth) acrylic esters are used alone or mixed with other polymerizable monomers, oligomers, polymers, dyes, pigments, inorganic fillers, etc. to prepare peroxides, persulfates, azobis compounds, In the presence of radical initiators such as ketone compounds, they are easily polymerized by radicals generated by thermal decomposition of these initiators or decomposition by irradiation of ultraviolet rays or radiation, and mechanical properties, heat resistance, weather resistance, oxidation resistance, etc. It produces excellent polymer.

Further, since pentaerythritol (meth) acrylic esters are easily copolymerized with various compounds having a carbon-carbon double bond, it is possible to adjust the physical properties of the polymer depending on the application. It is used in a wide range of fields as a raw material for paints, inks, coating agents, adhesives, adhesives, resins, rubbers, optical materials and the like.

The above-mentioned pentaerythritol (meth) acrylic esters are usually pentaerythritol and (meth)
It is obtained by an esterification reaction with acrylic acid or a transesterification reaction between pentaerythritol and a (meth) acrylic acid ester. Pentaerythritol (meth) acrylic esters obtained by these reactions are usually pentaerythritol tetra (meth) acrylic ester, pentaerythritol tri (meth) acrylic ester, pentaerythritol di (meth) acrylic ester, pentaerythritol mono (meth) acrylic ester. It contains oligomers such as acrylic esters and pentaerythritol poly (meth) acrylic esters.

This pentaerythritol (meth) acrylic ester becomes solid at room temperature, is inconvenient to handle, and has a small number of residual hydroxyl groups, especially when the content of pentaerythritol tetra (meth) acrylic ester is large. It becomes difficult to carry out a reaction utilizing the residual hydroxyl group in the (meth) acrylic ester, such as the synthesis of urethane acrylates by the reaction with isocyanates.

Moreover, pentaerythritol and (meth)
In the esterification reaction with acrylic acid and the transesterification reaction between pentaerythritol and (meth) acrylic acid ester, pentaerythritol is insoluble in general organic solvents, and tri (meth) acrylic ester of pentaerythritol produced by the reaction, etc. Dissolves in a solvent to preferentially produce pentaerythritol tetra (meth) acrylic ester, so that the amount of solid pentaerythritol tetra (meth) acrylic ester produced at room temperature increases,
The obtained pentaerythritol (meth) acrylic ester becomes a solid state at room temperature.

To solve this, Japanese Patent Laid-Open No. 1-199
No. 936, a partial ester such as pentaerythritol tri (meth) acrylic ester, pentaerythritol di (meth) acrylic ester, pentaerythritol mono (meth) acrylic ester, which suppresses the formation of pentaerythritol tetra (meth) acrylic ester. Pentaerythritol moiety (meth) acrylic ester which contains a large amount of body and can maintain a liquid state at room temperature [Pentaerythritol tetra (meth) acrylic ester may be contained within a range capable of maintaining a liquid state at room temperature. The same applies hereinafter. ] Is disclosed.
According to this production method, the esterification product water is allowed to exist in the reaction system in the first-stage reaction so that the esterification rate of pentaerythritol is 20 to 70% by weight, and then the product water is removed from the reaction system in the second-stage reaction. It has been shown that it is possible to suppress the production of pentaerythritol tetra (meth) acrylic ester by removing the esterification rate to make the esterification rate 75 to 95% by weight and stopping the reaction.

[0008]

However, when the reaction is carried out according to the method disclosed in JP-A-1-199936, the amount of pentaerythritol tetra (meth) acrylic ester formed is small, but the formation of an oligomer. Since the amount increases, it was impossible to obtain pentaerythritol partial (meth) acrylic esters with high purity and high yield.

The problem to be solved by the present invention is that a large amount of partial ester forms such as pentaerythritol tri (meth) acrylic ester, pentaerythritol di (meth) acrylic ester and pentaerythritol mono (meth) acrylic ester are produced. It is an object of the present invention to provide a method for producing a pentaerythritol partial (meth) acrylic ester which is liquid at room temperature with high purity and high yield.

[0010]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventors have found that pentaerythritol (containing a large amount of pentaerythritol tetra (meth) acrylic ester as a main component) By transesterifying a (meth) acrylic ester with an aliphatic alcohol in the presence of a catalyst, pentaerythritol tri (meth) acrylic ester, pentaerythritol di (meth) acrylic ester, pentaerythritol mono (meth) ester A large amount of partial ester such as acrylic ester is produced, the content of tetraester is decreased, and pentaerythritol partial (meth) acrylic ester which is liquid at room temperature is easily obtained. By adjusting the degree of transesterification by controlling the reaction time, reaction time, etc. Taerisurito - also found that it is easy to adjust the Le portions (meth) Ratio of tetraester and partial esters in the acrylic esters, and have completed the present invention.

That is, according to the present invention, pentaerythritol tetra (meth) acrylic ester-containing pentaerythritol (meth) acrylic ester and alcohol are esterified in the presence of a catalyst. Pentaerythritol moiety (meta) characterized by carrying out an exchange reaction
A method for producing an acrylic ester is provided.

The above-mentioned pentaerythritol (meth) acrylic ester used in the present invention may be any one containing pentaerythritol tetra (meth) acrylic ester as a main component, and is not limited by the production method and the like. ,
Usually, those obtained by a dehydration esterification reaction between pentaerythritol and (meth) acrylic acid or a transesterification reaction between pentaerythritol and (meth) acrylic acid ester are used. Pentaerythritol (meth) acrylic esters containing a large amount of this pentaerythritol tetra (meth) acrylic ester as a main component are (meth) acrylic acid and / or catalyst in excess in a dehydration esterification reaction. It can be easily obtained by using or prolonging the reaction time and then purifying, or by using an excess of (meth) acrylic acid ester and / or catalyst in the transesterification reaction, or prolonging the reaction time and then purifying. be able to.

For the purification of the pentaerythritol (meth) acrylic ester, a known purification operation such as washing with water or a combination of washing with alkali and washing with water can be employed.
However, when washed with water, water-soluble pentaerythritol di (meth) acrylic ester and mono (meth) acrylic ester are distilled out, so that as purified pentaerythritol (meth) acrylic esters, , A mixture of pentaerythritol tetra (meth) acrylic ester and pentaerythritol tri (meth) acrylic ester is obtained. In the present invention, this mixture is usually used as pentaerythritol tetra (meth) acrylic ester. Is used as a pentaerythritol (meth) acrylic ester containing as a main component.

The di (meth) acryl ester compound distilled by washing with water is recovered and added to the mixture of the tetra (meth) acryl ester compound and the tri (meth) acryl ester compound described above as pentaerythritol tetra. It can also be used in the present invention as pentaerythritol (meth) acrylic esters containing (meth) acrylic ester as a main component.

Pentaerythritol tetra (meth) in the above pentaerythritol (meth) acrylic ester.
The content of the acrylic ester is usually 40 to 100 parts by weight, preferably 55 to 100 parts, based on 100 parts by weight of the total of pentaerythritol (meth) acrylic esters.
Parts by weight.

The catalyst used in the transesterification of the present invention is not particularly limited as long as it is a compound that functions as a catalyst in a normal transesterification reaction such as an acidic compound, a basic compound, an organometallic compound. Here, as the acidic compound, for example, inorganic acids such as sulfuric acid, hydrochloric acid, chlorosulfuric acid and phosphoric acid,
Organic acids such as toluene sulfonic acid, p-toluene sulfonic acid, cresol sulfonic acid and methane sulfonic acid, acidic ion exchange resins and the like, and basic compounds include, for example, sodium hydroxide, potassium hydroxide, lithium hydroxide,
Metal hydroxides such as calcium hydroxide, sodium carbonate,
Metal carbonates such as potassium carbonate, lithium carbonate and calcium carbonate, metal bicarbonates such as sodium bicarbonate and potassium bicarbonate, and further examples of the organic metal compound include lauryl octyl tin, butyl tin oxide, isopropoxy titanium and acetylacetone. Examples include copper complexes and the like.

Of these, basic compounds, particularly metal hydroxides, are preferable because they have a high transesterification catalytic function, are inexpensive and easy to handle, and are more excellent in solubility in the reaction system and catalytic functions. Alkali metal hydroxides, especially potassium hydroxide, are preferred.

The amount of the transesterification catalyst added in the present invention varies depending on the desired composition of the pentaerythritol partial (meth) acrylic ester, but is based on 100 parts by weight of the pentaerythritol (meth) acrylic ester. It is usually 0.1 to 20 parts by weight, preferably 1 to 5 parts by weight.

The aliphatic alcohol used in the present invention is a linear or branched fatty acid which can preferentially form a (meth) acrylic ester in an equilibrium reaction with a pentaerythritol (meth) acrylic ester mixture. Group alcohols, among them, methanol, ethanol, n-propyl alcohol, i-propyl alcohol, n-butyl alcohol, i-butyl alcohol, s-butyl alcohol
Preferred are aliphatic alcohols having 1 to 4 carbon atoms such as ole and t-butyl alcohol, and most preferred is methanol from the viewpoint of easiness of reaction and easiness of removal after reaction.

The amount of the aliphatic alcohol used in the present invention is usually 0.1 to 100 parts by weight with respect to 1 part by weight of pentaerythritol (meth) acrylic ester, and the reaction rate is particularly high. 5 to 20 parts by weight is preferable in that the reaction rate is fast and the yield per reaction is small.

In the transesterification reaction of the present invention, the aliphatic alcohol used in the usual reaction is used also as a solvent, but it may be carried out by adding another organic solvent.
The other organic solvent used here is not particularly limited as long as it is a compound that does not affect the reaction, for example, benzene,
Examples thereof include aromatic hydrocarbons such as toluene and xylene, aliphatic hydrocarbons such as n-hexane, cyclohexane and n-octane, halogenated hydrocarbons such as dichloromethane, chloroform, carbon tetrachloride and chlorobenzene.

When an organic solvent other than alcohols used in the reaction is used, the amount of these solvents used is usually 0.5 with respect to 1 part by weight of pentaerythritol (meth) acrylic ester. 10 to 10 parts by weight.

The reaction temperature in the present invention is usually 0-10.
It is 0 ° C., preferably 0 to 30 ° C., and the reaction time is generally 5 minutes to 10 hours, preferably 20 minutes to 1 hour. In the reaction of the present invention, the progress of the reaction produces (meth) acrylic acid esters such as methyl (meth) acrylate. Although this reaction is an equilibrium reaction, the reaction proceeds sufficiently without removing the produced (meth) acrylic acid ester out of the system, but the (meth) acrylic acid ester is subjected to a single distillation or an alcohol or an organic compound. It is also possible to carry out the reaction while removing it outside the system by means such as azeotropic distillation with a solvent.

In the reaction of the present invention, a polymerization inhibitor may be used in combination to prevent the polymerization of pentaerythritol tetra (meth) acrylic ester-containing pentaerythritol (meth) acrylic ester as a main component. .
The polymerization inhibitor used is not particularly limited as long as it is a compound effective in inhibiting the polymerization of (meth) acrylic esters, and examples thereof include conventional polymerization inhibitors such as hydroquinone, methylhydroquinone, catechol and phenothiazine. be able to. Further, oxygen or a mixture of oxygen and an inert gas, such as air, may be used together with the above-mentioned polymerization inhibitor or alone to inhibit the polymerization.

After completion of the reaction, the intended pentaerythritol partial (meth) acrylic ester can be obtained by using a known separation and removal method or the like. For example, if the catalyst used is an acidic substance, it is neutralized with a base, and if it is a basic substance, it is neutralized with an acid and then filtered to remove the neutralized salt. The solvents and other organic solvents are distilled off under reduced pressure. Furthermore, if necessary, the degree of purification can be increased by adding an organic solvent immiscible with water to the obtained pentaerythritol partial (meth) acrylic ester and washing and concentrating with water. However, when washing with water, water-soluble pentaerythritol di (meth) acrylic ester and mono (meth) acrylic ester are distilled out, and thus, as purified pentaerythritol partial (meth) acrylic esters, As a result, a mixture of pentaerythritol tetra (meth) acrylic ester and pentaerythritol tri (meth) acrylic ester is obtained.

The pentaerythritol partial (meth) acrylic esters thus obtained are liquid at room temperature, and are pentaerythritol tri (meth) acrylic ester, pentaerythritol di (meth) acrylic ester, pentaerythritol monoester. A partial ester body such as (meth) acrylic ester and a tetraester body [pentaerythritol tetra (meth) acrylic ester],
The partial ester / tetraester weight ratio is usually 5
0/50 to 75/25, preferably 60/40 to 75 /
Included in the range of 25.

[0027]

EXAMPLES The present invention will be specifically described below with reference to reference examples, examples and comparative examples, but the contents of the present invention are not limited to the examples. In addition,% in the examples is based on weight unless otherwise specified.

Incidentally, pentaerythritol (meth) in the examples
Composition of acrylic esters and pentaerythritol partial (meth) acrylic esters [weight ratio of tetraester (4A) and triester (3A) (4A / 3
A)] is determined by gas chromatographic analysis, and the total content (purity) of tetraester and triester is G
Each was determined by PC analysis.

Reference Example 1 [Production of pentaerythritol tetra (meth) acrylic ester containing pentaerythritol tetra (meth) acrylic ester as a main component] Reflux condenser, water separator, air inlet pipe, temperature In a glass four-necked flask with a capacity of 300 ml equipped with a meter and a stirrer, acrylic acid 115.2 g (1.6 mol), pentaerythritol 68 g (0.5 mol), 3-hydroxy-
4-Methyl-benzenesulfonic acid 3.95 g (0.02
1 mol), p-toluenesulfonic acid 7.9 g (0.04
6 g), copper sulfate 0.098 g, and toluene 73.0 g as a solvent were charged. Next, heating and depressurizing the inside of the flask were started while blowing 7% oxygen concentration nitrogen gas into this flask at 30 ml / min, and the reaction temperature was kept at 65 ° C. while stirring the inner solution, and refluxed at this temperature. The dehydration esterification reaction was carried out for 15 hours while adjusting the degree of reduced pressure so that

Immediately after completion of the reaction, the reaction solution was cooled to room temperature, and 10.9 g of acrylic acid-containing reaction product water separated during the dehydration esterification reaction was added to the reaction solution, stirred for 10 minutes, and then allowed to stand for 30 minutes. After confirming that the two layers were separated, the lower layer was extracted from the bottom to separate the upper layer solution to obtain crude pentaerythritol acrylic ester.

To the obtained crude pentaerythritol acrylic ester, 18.3 g of 20% aqueous sodium hydroxide solution was added.
Was added, the mixture was stirred for 10 minutes, allowed to stand for 30 minutes, and after confirming that it was separated into two layers, the lower layer was separated and removed, and this operation was repeated once again.

Then, 26.0 g of a 7% aqueous sodium sulfate solution was added to this, and the mixture was stirred and allowed to stand still. After confirming that the layers were separated into two layers, the lower layer was separated and removed. Further, after substituting 26.0 g of water in place of the 7% sodium sulfate aqueous solution for the same stirring and standing, the lower layer was separated and removed, and this operation was repeated once more to obtain a tetraester body and a triester body. Pentaerythritol acrylic esters which were solid at room temperature and contained other components such as various polymers as components were obtained.

Composition of the resulting pentaerythritol acrylic ester [weight ratio of tetraester (4A) and triester (3A) (4A / 3A)], total content of tetraester and triester ( Purity) and yield are shown in Table 1.

Reference Examples 2 to 3 (same as above) A tetraester body and a triester body were the main components in the same manner as in Reference Example 1 except that the amount of acrylic acid and the reaction temperature were changed to the amounts and temperatures shown in Table 1. Then, normal temperature solid pentaerythritol acrylic esters containing other components such as various polymers were obtained.

Table 1 shows the composition of the obtained pentaerythritol acrylic ester [weight ratio (4A / 3A)], total content (purity) of tetraester and triester, and yield.

Reference Example 4 (same as above) 137.6 g of methacrylic acid instead of acrylic acid
In the same manner as in Reference Example 1 except that (1.6 mol) was used,
Pentaerythritol methacrylic esters containing a tetraester body and a triester body as main components and further containing other components such as various polymers were obtained.

Table 1 shows the composition of the obtained pentaerythritol methacrylic ester [weight ratio (4A / 3A)], total content (purity) of tetraester and triester, and yield.

[0038]

[Table 1]

Example 1 A 200 l glass flask was charged with 14.0 g of the pentaerythritol acrylic ester obtained in Reference Example 1 and 60.0 g of methanol, and 0.56 g of potassium hydroxide was added as a catalyst. The mixture was stirred at 20 ° C for 30 minutes.

After the reaction was completed, 0.98 g of sulfuric acid was added to adjust the pH of the system to 7, and the neutralized salt was removed by filtration.
Further, excess methanol and the generated methyl acrylate were removed under reduced pressure, and 50 g of toluene was added to the residue,
It was washed twice with 20 g of water. Toluene was distilled off under reduced pressure to obtain pentaerythritol partial acrylic esters which were liquid at room temperature and contained a large amount of triester.

Composition of the resulting pentaerythritol partial acrylic ester [weight ratio of tetraester (4A) and triester (3A) (4A / 3A)], total content of tetraester and triester (Purity) and yield are shown in Table 2.

Examples 2 to 3 Pentaerythritol obtained in Reference Example 2 or 3 in place of the pentaerythritol acrylic ester obtained in Reference Example 1
In the same manner as in Example 1 except that the acrylic ester was used, pentaerythritol partial acrylic ester which was liquid at room temperature and contained a large amount of triester was obtained.

Composition of the resulting pentaerythritol partial acrylic ester [weight ratio of tetraester (4A) and triester (3A) (4A / 3A)], total content of tetraester and triester (Purity) and yield are shown in Table 2.

Examples 4 to 6 Pentals in liquid form at room temperature containing a large amount of triesters were prepared in the same manner as in Example 1 except that the compounds shown in Table 1 were used as the transesterification catalysts in the amounts shown in the table. Erislith-
A partially acrylic ester was obtained.

Composition of the resulting pentaerythritol partial acrylic ester [weight ratio of tetraester (4A) and triester (3A) (4A / 3A)], total content of tetraester and triester (Purity) and yield are shown in Table 2.

Example 7 In the same manner as in Example 1 except that the pentaerythritol methacrylic ester obtained in Reference Example 4 was used in place of the pentaerythritol acrylic ester obtained in Reference Example 1. Thus, a pentaerythritol partial methacrylic ester which was liquid at room temperature and contained a large amount of triester was obtained.

Composition of pentaerythritol partial methacrylic ester obtained [weight ratio of tetraester (4A) and triester (3A) (4A / 3A)], total content of tetraester and triester The rate (purity) and the yield are shown in Table 2.

[0048]

[Table 2]

Examples 8 to 10 Alcohol 6 shown in Table 3 in place of 60 g of methanol
In the same manner as in Example 1 except that 0 g was used, pentaerythritol partial acrylic esters which were liquid at room temperature and contained a large amount of triester were obtained.

Composition of the resulting pentaerythritol partial acrylic ester [weight ratio of tetraester (4A) and triester (3A) (4A / 3A)], total content of tetraester and triester (Purity) and yield are shown in Table 2.

[0051]

[Table 3]

Comparative Example 1 A glass four-neck flask with a capacity of 300 ml equipped with a reflux condenser, a water separator, an air inlet tube, a thermometer and a stirrer was charged with 129.6 g (1.8 mol) of acrylic acid and penta. 68 g (5.0 mol) of erythritol, 3-hydroxy-
4-Methyl-benzenesulfonic acid 3.95 g (0.02
1 mol), p-toluenesulfonic acid 7.9 g (0.04
6 g), copper sulfate 0.098 g, and toluene 79.0 g as a solvent were charged. Next, heating the inside of the flask was started while blowing nitrogen gas of 7% oxygen concentration at 30 ml / min into this flask, and the inner solution was stirred.
The contents reached 90 ° C. in 1 hour, and at this temperature, the dehydration esterification reaction was carried out by heating and stirring the esterified water for 0.5 hour while allowing it to exist in the system, and then allowing the reaction temperature to reach 0.5 hour. Temperature to 110 ° C and reflux at this temperature for another 2
The dehydration esterification reaction was carried out for a period of time.

Immediately after completion of the reaction, the reaction solution was cooled to room temperature, and then 10.7 g of acrylic acid-containing reaction product water separated during the dehydration esterification reaction was added to this reaction solution, stirred for 10 minutes, and then allowed to stand for 30 minutes. After confirming that the two layers were separated, the washing water for the lower layer was withdrawn from the bottom to separate the upper layer solution to obtain crude pentaerythritol partial acrylic esters.

After adding 18.1 g of 20% aqueous sodium hydroxide solution to the obtained crude pentaerythritol acrylic ester, the mixture was stirred for 10 minutes and then allowed to stand for 30 minutes to confirm separation into two layers, and then the lower layer was separated and removed. Then, this operation was repeated once again.

Next, 25.0 g of a 7% aqueous sodium sulfate solution was added to this, and the mixture was stirred and allowed to stand, and after confirming that the layers were separated into two layers, the lower layer was separated and removed. Further, the same procedure as above except that 25.0 g of water was used instead of the 7% aqueous sodium sulfate solution was stirred and allowed to stand, and then the lower layer was separated and removed, and this operation was repeated once more to obtain the tetraester body and the triester body. Pentaerythritol partial acrylic esters which were liquid at room temperature and contained other components such as various polymers as components were obtained.

The weight ratio (4A / 3A) of the tetraester body (4A) and the triester body (3A) in the obtained pentaerythritol partial acrylic ester was 27.7 / 7.
2.2 was good, but the total content (purity) of tetraester and triester was 36%, and the yield was 63%.
Was low.

[0057]

According to the production method of the present invention, a room temperature liquid pentaerythritol partial (meth) acrylic ester containing a large amount of partial ester such as triester can be easily obtained with high purity and high yield. You get at a rate. Furthermore, it is also easy to adjust the ratio of the tetraester body and the partial ester body in the pentaerythritol partial (meth) acrylic ester.

Claims (5)

[Claims] 1. A transesterification reaction between a pentaerythritol (meth) acrylic ester containing pentaerythritol tetra (meth) acrylic ester as a main component and an aliphatic alcohol in the presence of a catalyst. A method for producing a pentaerythritol partial (meth) acrylic ester, comprising: 2. The content of pentaerythritol tetra (meth) acrylic ester in pentaerythritol (meth) acrylic ester is 100 parts by weight in total of pentaerythritol (meth) acrylic ester. for,
The production method according to claim 1, which is 40 to 100 parts by weight. 3. The method according to claim 1, wherein the catalyst is an alkali metal hydroxide. 4. The aliphatic alcohols have 1 to 1 carbon atoms.
4. The production method according to claim 1, which is the aliphatic alcohol of No. 4. 5. The catalyst is potassium hydroxide and the alcohol
3. The method according to claim 1 or 2, wherein the polyol is methanol.