JP2003064025A - Method for manufacturing (meth)acrylate having biphenyl skeleton - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a manufacturing method with which a (meth)acrylate having high crystallinity and strong hydrophobicity, and having a biphenyl skeleton can be manufactured in high purity. SOLUTION: The method for manufacturing a (meth)acrylate having a biphenyl skeleton is carried out as follows: an alcohol having a biphenyl skeleton and a carboxylic acid having a (meth)acryloyl group are subjected to an esterification reaction; subsequently, the reaction mixture is cooled to crystallize the (meth)acrylate obtained by the reaction and to separate the crystals from the reaction mixture; and the obtained crystals are washed with water or/and a water-soluble organic solvent.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing a (meth) acrylate having a high crystallinity and a strongly hydrophobic biphenyl skeleton with high purity, and producing a (meth) acrylate. It can be usefully used in the technical field.

[0002]

BACKGROUND OF THE INVENTION (Meth) acrylate having a biphenyl skeleton is used as a constituent of a thermosetting or active energy ray curable composition, and the cured product thereof is heat resistant and transparent. Due to its excellent properties such as water resistance and low water absorption, it has been used in various applications such as waterproof paints, transparent acrylic plates and liquid crystal materials used for waterproofing printed circuit boards constituting electronic circuits of electric appliances.

However, since the (meth) acrylate has very high crystallinity and strong hydrophobicity, it has been difficult to produce it in high purity. That is, if the reaction liquid is cooled after the esterification reaction of the raw material alcohol and the unsaturated carboxylic acid such as (meth) acrylic acid, the obtained (meth) acrylate is immediately crystallized, and the following purification step is performed. Was difficult. In order to solve this problem, there is a method of washing with an alkaline aqueous solution such as an aqueous solution of sodium hydroxide while the temperature of the obtained reaction liquid before crystallization of the (meth) acrylate is high. The reason for using the alkaline aqueous solution in the cleaning is to remove the acid catalyst used in the esterification reaction and the unreacted unsaturated carboxylic acid present in the reaction solution, but the cleaning is performed at high temperature. Got to be done in
There is a problem that the hydrolysis reaction of the (meth) acrylate proceeds and the reaction liquid is solidified due to the high hydrophobicity of the (meth) acrylate.

The present inventors have conducted extensive studies to find a production method capable of producing a (meth) acrylate having a biphenyl skeleton having high crystallinity and high hydrophobicity with high purity.

[0005]

As a result of various investigations to solve the above-mentioned problems, the present inventors obtained it after cooling the reaction solution and crystallizing it after the completion of the esterification reaction. By separating the crystals and washing the separated crystals with water or / and a water-soluble organic solvent, the acid catalyst, unreacted unsaturated carboxylic acid, etc. can be easily removed from the crystals, and the crystals have a biphenyl skeleton. The present invention has been completed by finding that (meth) acrylate can be produced with high purity. Hereinafter, the present invention will be described in detail. In the present specification, an acryloyl group or a methacryloyl group is referred to as a (meth) acryloyl group, an acrylate or a methacrylate is referred to as a (meth) acrylate, and acrylic acid or methacrylic acid is referred to as (meth).
Expressed as acrylic acid.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, first, an alcohol having a biphenyl skeleton and a carboxylic acid having a (meth) acryloyl group are subjected to an esterification reaction.

As the alcohol having a biphenyl skeleton (hereinafter sometimes simply referred to as alcohol), various alcohols having a biphenyl skeleton can be used, and alkylene oxide adducts of bisphenol and alkylene oxide adducts of bisphenol derivatives, etc. Is mentioned. Examples of the alkylene oxide include ethylene oxide and propylene oxide. The number of alkylene oxides added is preferably 1 to 8. In the case where 9 or more alkylene oxides are added, the hydrophilicity of the obtained (meth) acrylate becomes too strong, which may reduce the yield of the final product. Preferred alcohols in the present invention are represented by the following formula (3).

[0008]

[Chemical 3]

In the formula (3), n represents an integer of 1 to 4, R ² represents an alkylene group, R ^{3 to} R ⁶ represent hydrogen atoms,
Represents an alkyl group or an alkoxyalkyl group. Examples of the alkylene group for R ² include an ethylene group and a propylene group. When R ^{3 to} R ⁶ are alkyl groups, those having 1 to 6 carbon atoms are preferable. Examples of the alkoxyalkyl group of R ^{3 to} R ⁶ include a methoxymethyl group, a methoxyethyl group, a methoxypropyl group, an ethoxymethyl group, an ethoxyethyl group and an ethoxypropyl group.

As the carboxylic acid having a (meth) acryloyl group (hereinafter referred to as an unsaturated carboxylic acid), various ones can be used, including (meth) acrylic acid and (meth) acrylic acid such as (meth) acrylic acid dimer. Examples include multimers.

The amount of the unsaturated carboxylic acid used with respect to the alcohol is not particularly limited, but if the efficiency of the esterification reaction and the easiness of purification of the reaction product are taken into consideration, 2. It is used in the range of 1 to 4 mol, preferably 2.2 to 2.5 mol.

The esterification reaction may be carried out according to a conventional method, for example, a method of heating and stirring an alcohol and an unsaturated carboxylic acid in the presence of an acid catalyst and a radical polymerization inhibitor in an organic solvent.

The acid catalyst is not particularly limited as long as it has a higher acidity than the unsaturated carboxylic acid used as a raw material, but preferable ones are inorganic acids such as hydrochloric acid, hydrobromic acid, sulfuric acid and phosphoric acid. Benzenesulfonic acid,
Organic acids such as p-toluenesulfonic acid, trichloroacetic acid, oxalic acid and formic acid or salts thereof; Lewis acids such as zinc chloride, tin chloride, ferric chloride, cupric chloride and cupric sulfate; cation exchange Examples thereof include resins and activated clay. Among these, sulfuric acid, phosphoric acid, p-toluenesulfonic acid, and sodium p-toluenesulfonate are preferable. The amount of the acid catalyst used may be in accordance with the amount used in a general esterification reaction.
0.0001-0.1 mol is preferable, and 0.001-
0.05 mol is more preferable.

As the radical polymerization inhibitor, a conventionally known ordinary radical polymerization inhibitor is used, and it is not particularly limited as long as it is a compound capable of capturing radicals. Preferred examples include hydroquinone, methoxyhydroquinone, ethoxyhydroquinone, methylhydroquinone, phenothiazine, t-butylcatechol and hypophosphorous acid. These radical polymerization inhibitors may be used alone or in combination of two or more.
The radical polymerization inhibitor is usually preferably used in the range of 10 to 10000 ppm, more preferably 100 to 5000 ppm, based on the unsaturated carboxylic acid.

In the esterification reaction of the present invention, the esterification reaction can easily proceed, the amount of acid catalyst and unreacted substances in the crystal can be reduced, and the subsequent purification step can be facilitated. Preference is given to using organic solvents. The organic solvent is not particularly limited except that it reacts with the unsaturated carboxylic acid used as a raw material, for example, alcohols and amines, but in the esterification reaction, the water produced is reacted with Since it is preferable to distill off to the outside of the system, a solvent which can easily distill off the water generated in the system to the outside of the system, that is, an organic solvent which is insoluble in water and azeotropic with water is preferable. Examples of the organic solvent include benzene, toluene, xylene, cumene,
Examples thereof include dichloroethane and trichloroethane. Of these, toluene is particularly preferable because it has a boiling point close to that of water, has good azeotropic properties with water, is inexpensive, and has a relatively low environmental load. The amount of the organic solvent used is not particularly limited, but is usually preferably 5 parts by mass or less, more preferably 0.8 to 2 parts by mass or less, based on the total weight of the alcohol and the unsaturated carboxylic acid. Is. 5
If it exceeds the mass times, the yield of crystals may decrease.

The reaction temperature of the esterification reaction is usually 70 to 150 ° C, preferably 100 to 135 ° C. The reaction is usually carried out under normal pressure, but depending on the boiling point of the organic solvent used, it may be carried out under pressure or under reduced pressure so that the reaction temperature falls within the above temperature range. In the present invention, the reaction time is not particularly limited, but is usually in the range of 1 to 20 hours.

In the present invention, the reaction liquid containing the (meth) acrylate which is the reaction product after the esterification reaction is cooled to crystallize the (meth) acrylate. As a method for cooling the reaction solution, it may be appropriately set depending on the physical properties of the target (meth) acrylate and the target yield, but if the cooling rate is too fast, the acid catalyst and unreacted components are incorporated into the crystal. Since the purity of crystals may decrease,
A method in which the reaction solution is left at room temperature and gradually cooled is preferable. If the reactor is large and the cooling method is difficult, a water bath or an ice bath can be used.

The liquid temperature of the reaction liquid after cooling is -5 to 5
0 degreeC is preferable, More preferably, it is 10 to 30 degreeC.
If this temperature is lower than -5 ° C, the purity may decrease, while if it exceeds 50 ° C, the crystal yield may decrease. The holding time after cooling is the desired (meta)
The time may be appropriately set depending on the physical properties of the acrylate and the desired yield, but it is preferably 3 to 40 hours, more preferably 5 to 24 hours. If this time is shorter than 3 hours, the yield may decrease, and if it is longer than 40 hours, the yield improves but the production efficiency deteriorates.

In the present invention, the crystals obtained by the above method are separated from the reaction solution. Although various methods can be adopted as the separation method, filtration is preferable because it is simple and easy. As a filtration method, a conventional method may be used, and pressure filtration, suction filtration and the like are preferable since the filtration rate is high. In the case of filtration, for the purpose of recovering the crystals remaining in the reactor, a small amount of an organic solvent can be poured into the reactor and then poured into a filtration device.

The separated crystals are washed with water or / and a water-soluble organic solvent (hereinafter collectively referred to as a detergent) to purify the crystals. By the washing, it is possible to dissolve the acid catalyst used in the esterification reaction and the unreacted unsaturated carboxylic acid contained in the crystal, which is poorly soluble in the organic solvent, and the unsaturated carboxylic acid in the detergent to remove it from the crystal. it can. As the detergent, water or a mixed solvent of water and a water-soluble organic solvent is preferable. Examples of the water-soluble organic solvent include lower alcohols such as methanol and ethanol, highly hydrophilic ketones such as acetone and methyl ethyl ketone, and highly hydrophilic ethers such as tetrahydrofuran and dioxane. The amount of the detergent used may be appropriately set according to the reaction conditions and the amount of unsaturated carboxylic acid and acid catalyst remaining in the crystals, but is preferably 3 to 20 times the mass of the obtained crystals. Also, by measuring the pH of the cleaning agent after cleaning,
It is possible to roughly know the residual amount of the unsaturated carboxylic acid and the acid catalyst remaining in the crystal, and it is preferable to set the usage amount of the cleaning agent and the number of times of cleaning by this.

When the crystal contains a large amount of acid catalyst and unreacted unsaturated carboxylic acid, it is preferable to use a detergent in which a basic substance is dissolved. Examples of the basic substance include sodium hydroxide and potassium hydroxide. When using a basic substance dissolved as a cleaning agent, wash with neutral water after washing, or with a weakly acidic aqueous solution such as ammonium sulfate water, and adjust the pH.
Is preferably lowered. However, when an aqueous solution of ammonium sulfate or the like is used, ammonium sulfate may remain in the crystals, so it is preferable to adjust the pH by ordinary washing with water unless particularly necessary. The amount of rinsing water used at this time is not particularly limited, but the pH of rinsing water after cleaning
It may be washed while observing until the desired pH is reached.

A polymerization inhibitor may be dissolved in these detergents before use. The amount of the polymerization inhibitor used is not particularly limited, but usually 50 to 1000 pp in the detergent.
It is preferably in the range of m.

Examples of the washing method include a method in which the crystals separated by filtration are directly poured into a washing agent for washing, a method in which the crystals are once transferred to a container such as a flask, a washing agent is added, and the mixture is stirred. When adopting the washing method by stirring,
The stirring time is not particularly limited, but is preferably about 5 minutes to 2 hours. Also, the container may be heated during stirring. However, if the heating temperature is too high, a polymerization reaction may occur and gelation may occur, so heating is preferably maintained at about 40 to 80 ° C. When heating the container, it is preferable to add a polymerization inhibitor to the detergent. If necessary, air or a nitrogen-oxygen mixture may be bubbled. The flow rate of the gas at this time is not particularly limited.

The remaining amount of the acid catalyst and unsaturated carboxylic acid remaining in the crystal can be measured by measuring the acid value of the crystal after the washing step. When the acid value after the washing step is high, the washing step may be repeated, and when the acid value is sufficiently low, the subsequent drying step is performed. When water is used for washing, it takes a long time to dry, so for the purpose of shortening the drying time, wash the crystals with a solvent having a low boiling point and high compatibility with water, such as methanol or acetone, to remove the water in the crystals. It is also possible to dry after replacing. The organic solvent used at this time is preferably a solvent in which a polymerization inhibitor is dissolved in an amount of 50 to 1000 ppm.

In the present invention, drying is preferably carried out after the washing step. Although various dryers can be used in the drying step, it is preferable to use a vacuum dryer for the purpose of efficiently removing water and organic solvent in a short time. The drying time is not particularly limited, but the drying time is preferably 1 to 48 hours in order to completely remove the residual water content and the unsaturated carboxylic acid present in a very small amount, and heating may be performed at this time. However, since it is under anaerobic conditions, the polymerization reaction is likely to occur, so heating is 100
It is preferable not to exceed ℃.

The production method of the present invention can be preferably applied to a production method of a (meth) acrylate having a biphenyl skeleton represented by the following (1) or (2), which has high crystallinity and strong hydrophobicity.

[0027]

[Chemical 4]

[In the formula (1), n represents an integer of 1 to 4, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group, R ^{3 to} R ⁶ represent a hydrogen atom or an alkyl group. Alternatively, it represents an alkoxyalkyl group. ]

[0029]

[Chemical 5]

[In the formula (2), n represents an integer of 1 to 4, R ¹ and R ⁷ represent a hydrogen atom or a methyl group, R ² represents an alkylene group, and R ^{3 to} R ⁶ represent a hydrogen atom. Represents an alkyl group or an alkoxyalkyl group. ]

Specific examples of R ^{2 to} R ^{6 in} the formulas (1) and (2) include the same ones as described above.

[0032]

EXAMPLES The present invention will be described more specifically with reference to Examples and Comparative Examples below. Example 1 To a 1 L three-necked flask equipped with a Dean-Stark tube, a cooling tube, a thermometer and a stirrer, 200 mL of toluene, p
-8.04 g (0.042 mol) of sodium toluene sulfonate, 0.20 g of methoxyhydroquinone, an ethylene oxide adduct of biphenyl [in the formula (3), R ²
Is an ethylene group, R ^{3 to} R ⁶ are hydrogen atoms, and a compound of n = 1]
128 g (0.47 mol) and acrylic acid 74.1 g
After charging (1.03 mol), the temperature was raised to 130 ° C. with stirring and the reaction was carried out for 3 hours. After completion of the reaction, the flask was allowed to stand at room temperature for 15 hours for crystallization and then filtered through a Buchner funnel to separate crystals from the reaction solution. 1 separated crystal
Transfer to L flask and add hydroquinone 250ppm
300 mL of water in which was dissolved was added and heated to 60 ° C for 1
Stir for hours. After completion of stirring, the crystals were collected by filtration with a Buchner funnel. At this time, the pH of the wash water was about 3.
Since the pH of the washing water after repeating the same washing operation three times was about 6, the obtained crystals were washed on a Buchner funnel with 50 mL of acetone in which 250 ppm of methoxyhydroquinone was dissolved, and then at 12 ° C. at 12 ° C. It was dried under reduced pressure for an hour. When the residual amount of toluene in the obtained crystals was measured by gas chromatography, it was not detected at all.
The acid value of the obtained crystal was measured and found to be <0.01.
It was meq / g. The weight of the obtained crystals is 140.5 g.
(Yield 78.1%). The melting point, elemental analysis and ¹ H NMR spectrum (27
The results of measurement at 0 MHz and a measurement solvent CDCl ₃ ) are as follows, and it was confirmed that the product was the target product.

O Melting point: 94 to 96 ° C o Elemental analysis (%) Calculated value: C; 69.10, H; 5.80, O; 25.1
0 Found: C; 68.64, H; 6.10, O; 25.2
Three

○ ¹ H NMR spectrum The structural formula of the acrylate obtained in Example 1 is shown below.
In (4), each proton is numbered a to g. The attribution is as shown in Table 1.

[0035]

[Chemical 6]

[0036]

[Table 1]

Example 2 In a flask similar to that of Example 1, 200 mL of toluene, p
-Sodium toluene sulfonate 12.06 g (0.063
Mol), 0.20 g of methoxyhydroquinone, 128 g (0.47 mol) of an ethylene oxide adduct of biphenyl, and 148.4 g of β-acryloxypropionic acid.
(1.03 mol) was charged, the temperature was raised to 125 ° C. with stirring, and the mixture was reacted for 4 hours. After completion of the reaction, the flask was allowed to stand at room temperature for 12 hours for crystallization and then filtered through a Buchner funnel to separate crystals from the reaction solution. The separated crystals were transferred to a 1 L flask, 200 ppm of hydroquinone was dissolved therein, 300 mL of water was added, and the mixture was heated to 70 ° C. and stirred for 1 hour. After completion of stirring, the crystals were collected by filtration with a Buchner funnel. At this time, the pH of the wash water was about 3. The same water washing operation was repeated 3 times. Since the pH of the washing water after the third washing was about 6, the obtained crystals were washed with acetone and dried in the same manner as in Example 1. When the residual amount of toluene in the obtained crystals was measured by gas chromatography, it was not detected at all. The acid value of the obtained crystal was measured and found to be <0.01 meq / g
Met. The weight of the obtained crystals was 163.8 g (yield 6
It was 6.2%). The melting point, elemental analysis and ¹ H NMR spectrum of the obtained product were measured in the same manner as in Example 1, and the results are as follows and were confirmed to be the desired products.

Melting point: 140 to 142 ° C. Elemental analysis (%) Calculated value: C; 63.87, H; 5.74, O; 30.3
9 Found: C; 64.34, H; 6.10, O; 29.5.
Two

Assignment of ¹ H NMR spectrum The structural formula of the acrylate obtained in Example 2 is represented by the following formula (5).
, And each proton is numbered a to i.
The attribution is as shown in Table 1.

[0040]

[Chemical 7]

[0041]

[Table 2]

Example 3 An esterification reaction was carried out in the same manner as in Example 1, using the same raw materials as in Example 1. After completion of the reaction, crystallization was carried out in the same manner as in Example 1, and crystals were separated from the reaction solution by filtration. The separated crystals were transferred to a 1 L flask and washed once with water in the same manner as in Example 1. At this time, the pH of the wash water was about 3. Then, the crystals were washed with 200 mL of a 0.5 mass% sodium hydroxide aqueous solution,
The pH of the wash water was about 11. Hydroquinone 250
When the crystal was washed twice with 200 mL of water in which ppm was dissolved, the pH was about 7. The crystals were washed with acetone and dried in the same manner as in Example 1. When the residual amount of toluene in the obtained crystals was measured by gas chromatography, it was not detected at all. The acid value of the obtained crystal was measured and found to be <0.01 meq / g
Met. The weight of the obtained crystal was 141.2 g (yield 7
It was 8.5%). When the melting point of the crystal was confirmed, it was 9
4 to 96 ° C., which was the same as the acrylate obtained in Example 1.

Comparative Example 1 Using the same raw materials as in Example 1, the esterification reaction was carried out in the same manner as in Example 1. After the reaction is completed, the liquid temperature is 60
0.5% by mass, which had been cooled in an ice bath to prevent hydrolysis while crystals were not precipitated,
The mixture was neutralized by pouring it into an aqueous solution of sodium hydroxide, but at the same time when the mixture was mixed, the entire reaction liquid became a solid, and two phases of solid and liquid were formed. The liquid phase was only water, and the pH of the aqueous phase was> 11. The solid phase obtained above is separated by filtration, and a 1% by mass aqueous solution of ammonium sulfate 4
When 00 mL was added and stirred for 5 minutes, the pH of the aqueous layer was about 3. This solid was dried under reduced pressure at 50 ° C. for 12 hours to obtain 161.5 g (yield 89.9%) of crystals. The obtained solid has a strong acrylic acid odor and an acid value of 5.1 me.
The quality was as high as q / g, and the quality was not acceptable for practical use. In Comparative Example, it is considered that the purification was difficult because the reaction liquid took in toluene, unreacted unsaturated carboxylic acid and the like and solidified entirely in the neutralization with the aqueous sodium hydroxide solution.

[0044]

According to the present invention, it is possible to produce a (meth) acrylate having a biphenyl skeleton with high purity.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazumasa Inada             1 Toago, 1 Funami-cho, Minato-ku, Nagoya-shi, Aichi             Synthetic Co., Ltd. F-term (reference) 4H006 AA02 AC48 AD15 AD17 BJ50                       BP30

Claims (4)

[Claims] 1. An alcohol having a biphenyl skeleton and a carboxylic acid having a (meth) acryloyl group are subjected to an esterification reaction, and then the reaction solution is cooled to crystallize the (meth) acrylate obtained by the reaction. Separated from
A method for producing a (meth) acrylate having a biphenyl skeleton, which comprises washing the separated crystals with water and / or a water-soluble organic solvent. 2. The (meth) acrylate having a biphenyl skeleton according to claim 1, wherein the (meth) acrylate having a biphenyl skeleton is a compound represented by the following general formula (1) or (2). Method for producing acrylate. [Chemical 1] [In the formula (1), n represents an integer of 1 to 4, R ¹ represents a hydrogen atom or a methyl group, R ² represents an alkylene group,
R ^{3 to} R ⁶ represent a hydrogen atom, an alkyl group or an alkoxyalkyl group. ] [Chemical 2] [In the formula (2), n represents an integer of 1 to 4, and R ¹ and R
⁷ represents a hydrogen atom or a methyl group, R ² represents an alkylene group, and R ^{3 to} R ⁶ represent a hydrogen atom, an alkyl group or an alkoxyalkyl group. ] 3. The method for producing a (meth) acrylate having a biphenyl skeleton according to claim 1 or 2, wherein the crystallized (meth) acrylate is separated from the reaction solution by filtration. 4. The method for producing a (meth) acrylate having a biphenyl skeleton according to claim 1, wherein the water or / and the water-soluble organic solvent contains an alkaline substance.