JP6039281B2 - Method for producing 4-hydroxybutyl acrylate - Google Patents

Description

  The present invention relates to a method for producing 4-hydroxybutyl acrylate. More specifically, the present invention relates to a method for producing 4-hydroxybutyl acrylate useful as a raw material for medical pressure-sensitive adhesives, coating materials for electronic materials, photosensitive resin compositions and the like.

  As a method for producing a hydroxyalkyl monoacrylate, a method is known in which acrylic acid and alkanediol are esterified using a catalyst such as sulfuric acid or paratoluenesulfonic acid (see, for example, Patent Document 1). However, the above method has a drawback that unreacted acrylic acid remains in the produced 4-hydroxybutyl acrylate in an amount that hinders use as a raw material for medical adhesives, coating materials for electronic materials, and the like. There is.

  As a method for eliminating the disadvantages of the above method, a method for producing a hydroxyalkyl monoacrylate by esterifying an acrylic acid derivative and an alkanediol using a stannoxane compound as a reaction catalyst (see, for example, Patent Document 2) , A method of producing 4-hydroxybutyl acrylate by transesterifying 1,4-butanediol and methyl acrylate using a stannoxane catalyst as a reaction catalyst (for example, paragraph [0020] of Patent Document 3, Patent Document 4 paragraphs [0033]-[0034]) are proposed. However, since acrylates obtained by these methods remain in an amount in which an acid component such as acrylic acid has skin irritation and may cause corrosion, the acrylate contains medical adhesive, electronic It cannot be said that it is suitable for raw materials such as coating agents for materials.

  Therefore, as a method for removing the free carboxylic acid contained in the produced hydroxyalkyl acrylate, an alkanediol and an acrylate ester are transesterified using a distanoxane compound as a reaction catalyst. A method of bringing an organic solution containing an acid into contact with an alkaline aqueous solution has been proposed (see, for example, Patent Document 5). However, the above method requires an alkaline aqueous solution, so that the hydroxyalkyl acrylate is hydrolyzed, so that the productivity of the hydroxyalkyl acrylate is inferior.

  Therefore, in recent years, 4-hydroxybutyl acrylate having a low content of an acid component that can be suitably used as a raw material for medical adhesives, coating materials for electronic materials, photosensitive resin compositions and the like that are easily affected by acid. Development of a manufacturing method is desired.

German Patent No. 1518572 Japanese Patent Laid-Open No. 11-43466 JP 2003-155263 A JP 2007-161636 A JP 2000-159727 A

  The present invention has been made in view of the above prior art, and is an acid that can be suitably used as a raw material for medical adhesives, coating materials for electronic materials, photosensitive resin compositions, and the like that are easily adversely affected by acids. It aims at providing the manufacturing method of 4-hydroxybutyl acrylate with low content rate of a component.

The present invention
(1) A process for producing 4-hydroxybutyl acrylate by transesterification of 1,4-butanediol and an alkyl acrylate, wherein 1,4-butanediol and acrylic are in the presence of a transesterification catalyst. Acid alkyl ester is transesterified, and the resulting reaction mixture is mixed with water and an extraction solvent containing an aliphatic hydrocarbon compound to extract 4-hydroxybutyl acrylate contained in the reaction mixture into an aqueous layer. Then, the water layer is brought into contact with the ion exchange resin, the water layer brought into contact with the ion exchange resin and the extraction solvent containing the aromatic hydrocarbon compound are mixed, and contained in the water layer 4 -Extracting 4-hydroxybutyl acrylate by extracting hydroxybutyl acrylate into an aromatic hydrocarbon compound Method for producing 4-hydroxybutyl acrylate, which comprises yield, and (2) using a dialkyltin oxide as transesterification catalyst, the presence of 1,4-butanediol and acrylic acid alkyl esters of the dialkyltin oxide The dialkyltin oxide is recovered from the reaction mixture containing 4-hydroxybutyl acrylate obtained by the transesterification reaction in Step 1, and the recovered dialkyltin oxide is converted into 1,4-butanediol and an alkyl acrylate ester. producing how the 4-hydroxybutyl acrylate according to the reused as transesterification catalysts in which an ester exchange reaction (1)
About the.

  According to the present invention, 4-hydroxybutyl having a low content of an acid component that can be suitably used as a raw material for medical adhesives, coating materials for electronic materials, photosensitive resin compositions, and the like that are easily affected by acid. An acrylate is provided.

  As described above, the method for producing 4-hydroxybutyl acrylate of the present invention is a method for producing 4-hydroxybutyl acrylate by transesterifying 1,4-butanediol and an alkyl acrylate ester. After transesterifying 1,4-butanediol and alkyl acrylate in the presence of an exchange catalyst, 4-hydroxybutyl acrylate is extracted from the reaction mixture containing 4-hydroxybutyl acrylate and recovered. It is characterized by that.

  In the present invention, first, 1,4-butanediol and an acrylic acid alkyl ester are transesterified.

  Examples of the alkyl acrylate ester include methyl acrylate, ethyl acrylate, propyl acrylate, n-butyl acrylate, isobutyl acrylate, tert-butyl acrylate, and the like. You may use independently and may use 2 or more types together. Among the acrylic acid alkyl esters, from the viewpoint of efficiently separating the 4-hydroxybutyl acrylate to be produced and the raw material acrylic acid alkyl ester, an alkyl alkyl ester having 1 to 4 carbon atoms in the alkyl group is preferable. Acrylic acid alkyl ester having 1 to 3 carbon atoms is more preferred, and methyl acrylate is more preferred.

  The amount of acrylic acid alkyl ester per mole of 1,4-butanediol is preferably 0.5 mol or more from the viewpoint of increasing the reaction rate, and from the viewpoint of reducing the amount of unreacted acrylic acid alkyl ester, Preferably it is 5 mol or less, More preferably, it is 3 mol or less.

  In the present invention, a transesterification catalyst is used when 1,4-butanediol and an acrylic acid alkyl ester are transesterified.

  Examples of the transesterification catalyst include a tin compound, a metal salt of dithiocarbamate, a titanium compound, a thallium compound, a lead compound, a chromium compound, a metal alcoholate, and lithium hydroxide, but the present invention is limited only to such examples. It is not something. These transesterification catalysts may be used alone or in combination of two or more.

  Of the transesterification catalysts, tin compounds and dithiocarbamic acid metal salts are preferred, and tin compounds are more preferred. When a tin compound or a metal salt of dithiocarbamate is used as the transesterification catalyst, 1,4-butanediol and methyl acrylate are transesterified to produce 4-hydroxybutyl acrylate. 4-Hydroxybutyl acrylate, which can efficiently proceed the transesterification reaction between butanediol and alkyl acrylate, does not require the use of organic acids such as acrylic acid and acetic acid, and has a low acid content The outstanding effect that it can manufacture efficiently is show | played.

  Examples of tin compounds include dialkyltin oxides, tin carboxylates such as tin octylate, dialkyltin dialkyl esters such as dibutyltin dilaurate, monoalkyltin oxides such as monobutyltin oxide, and stannous chloride. The invention is not limited to such examples. These tin compounds may be used alone or in combination of two or more.

  Of the tin compounds, dialkyltin oxide is preferred. When dialkyltin oxide is used as the transesterification catalyst, 1,4-butanediol and 1,4-butanediol and methyl acrylate are transesterified to produce 4-hydroxybutyl acrylate. 4-hydroxybutyl acrylate with low acid component content can be efficiently produced without requiring the use of organic acids such as acrylic acid and acetic acid, while allowing the transesterification reaction with alkyl acrylates to proceed efficiently. There is an advantage that it can be manufactured.

  Examples of the dialkyl tin oxide include dialkyl tin oxide having 4 to 18 carbon atoms in the alkyl group such as dibutyl tin oxide, dioctyl tin oxide, and dilauryl tin oxide. However, the present invention is limited to such examples. It is not a thing. These dialkyltin oxides may be used alone or in combination of two or more. Among these dialkyl tin oxides, from the viewpoint of promoting the transesterification reaction between 1,4-butanediol and alkyl acrylate, dialkyl tin oxides having 4 to 12 carbon atoms in the alkyl group are preferred. A dialkyltin oxide having 4 to 8 carbon atoms is more preferred, dibutyltin oxide and dioctyltin oxide are more preferred, and dioctyltin oxide is even more preferred.

  Examples of the metal salt of dithiocarbamate include sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dipropyldithiocarbamate, sodium dibutyldithiocarbamate, potassium dimethyldithiocarbamate, potassium diethyldithiocarbamate, potassium dipropyldithiocarbamate, potassium dibutyldithiocarbamate , Sodium methylethyldithiocarbamate, sodium methylpropyldithiocarbamate, sodium ethylpropyldithiocarbamate, sodium methylbutyldithiocarbamate, potassium methylethyldithiocarbamate, potassium methylpropyldithiocarbamate, potassium ethylpropyldithiocarbamate, methylbutyldithiocarbamate Potassium, sodium diphenyldithiocarbamate, sodium ditolyldithiocarbamate, sodium dixylyldithiocarbamate, sodium dibiphenyldithiocarbamate, sodium dinaphthyldithiocarbamate, sodium dianthryldithiocarbamate, sodium diphenanthryldithiocarbamate, potassium diphenyldithiocarbamate, Potassium ditolyldithiocarbamate, potassium dixylyldithiocarbamate, potassium dibiphenyldithiocarbamate, potassium dinaphthyldithiocarbamate, potassium dianthryldithiocarbamate, potassium diphenanthryldithiocarbamate, sodium dibenzyldithiocarbamate, sodium diphenylethyldithiocarbamate, Zimechi Dithiocarbamate alkali metal salts such as sodium benzyldithiocarbamate, sodium dinaphthylmethyldithiocarbamate, potassium dibenzyldithiocarbamate, potassium diphenylethyldithiocarbamate, potassium dimethylbenzyldithiocarbamate, potassium dinaphthylmethyldithiocarbamate; and magnesium dimethyldithiocarbamate, Magnesium diethyldithiocarbamate, magnesium dipropyldithiocarbamate, magnesium dibutyldithiocarbamate, calcium dimethyldithiocarbamate, calcium diethyldithiocarbamate, calcium dipropyldithiocarbamate, calcium dibutyldithiocarbamate, magnesium methylethyldithiocarbamate, methyl Magnesium propyl dithiocarbamate, magnesium ethylpropyldithiocarbamate, magnesium methylbutyldithiocarbamate, calcium methylethyldithiocarbamate, calcium methylpropyldithiocarbamate, calcium ethylpropyldithiocarbamate, calcium methylbutyldithiocarbamate, magnesium diphenyldithiocarbamate, ditolyldithiocarbamine Magnesium oxide, magnesium dixylyl dithiocarbamate, magnesium dibiphenyldithiocarbamate, magnesium dinaphthyldithiocarbamate, magnesium dianthryldithiocarbamate, magnesium diphenanthryldithiocarbamate, calcium diphenyldithiocarbamate, ditolyldithiocarbamine Calcium, calcium dixylyl dithiocarbamate, calcium dibiphenyldithiocarbamate, calcium dinaphthyldithiocarbamate, calcium dianthryldithiocarbamate, calcium diphenanthryldithiocarbamate, magnesium dibenzyldithiocarbamate, diphenylethyldithiocarbamate, dimethylbenzyldithiocarbamate Examples include magnesium, dinaphthylmethyl dithiocarbamate magnesium, calcium dibenzyldithiocarbamate, calcium diphenylethyldithiocarbamate, calcium dimethylbenzyldithiocarbamate, calcium dinaphthylmethyldithiocarbamate, and the like. , Such an example The present invention is not limited to. These dithiocarbamic acid metal salts may be used alone or in combination of two or more.

  Among dithiocarbamic acid metal salts, dialkyldithiocarbamate having 1 to 4 carbon atoms in the alkyl group is preferable, since it can be separated and recovered by water washing after the transesterification reaction and reused. Is more preferably an alkali metal dialkyldithiocarbamate of 1 to 4, sodium dimethyldithiocarbamate, sodium diethyldithiocarbamate, sodium dipropyldithiocarbamate, sodium dibutyldithiocarbamate, potassium dimethyldithiocarbamate, potassium diethyldithiocarbamate, dipropyldithiocarbamate More preferred are potassium and potassium dibutyldithiocarbamate.

  Examples of the titanium compound include tetraethyl titanate, tetraisopropyl titanate, tetrabutyl titanate, tetramethoxy titanate, tetraethoxy titanate, tetrabutoxy titanate, and the like, but the present invention is not limited to such examples. These titanium compounds may be used alone or in combination of two or more.

  Examples of the metal alcoholate include alkali metal alcoholates such as sodium methylate, sodium ethylate, lithium methylate, and lithium ethylate; alkaline earth metal alcoholates such as calcium methylate, calcium ethylate, magnesium methylate, and magnesium ethylate. And aluminum alcoholates such as aluminum methylate and aluminum ethylate, and the like, but the present invention is not limited to such examples. These metal alcoholates may be used alone or in combination of two or more.

  The amount of the transesterification catalyst per 1 mol of acrylic acid alkyl ester is preferably 0.00001 mol or more, more preferably from the viewpoint of efficiently proceeding the transesterification reaction between 1,4-butanediol and alkyl acrylate. It is 0.0001 mol or more, preferably 0.01 mol or less, more preferably 0.005 mol or less.

  When reacting 1,4-butanediol with alkyl acrylate, 1,4-butanediol and alkyl acrylate are present in the presence of a polymerization inhibitor from the viewpoint of suppressing the polymerization of alkyl acrylate. It is preferable to react with an ester.

  Examples of the polymerization inhibitor include 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetamino-2,2,6,6-tetramethylpiperidine-N-oxyl, 4- Benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-oxo-2,2,6,6-tetramethylpiperidine-N-oxyl, 2,2,6,6-tetramethylpiperidine N-oxy radical compounds such as -N-oxyl; paramethoxyphenol, 2,2'-methylenebis (4-ethyl-6-tert-butylphenol), 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-N, N-dimethylamino-p-cresol, 2,4-dimethyl-6-tert-butylphenol, 4 phenolic compounds such as tert-butylcatechol, 4,4′-thio-bis (3-methyl-6-tert-butylphenol), 4,4′-butylidene-bis (3-methyl-6-tert-butylphenol); Quinone compounds such as methoquinone, hydroquinone, 2,5-di-tert-butylhydroquinone, 2,6-di-tert-butylhydroquinone, benzoquinone; copper dialkyldithiocarbamates such as cuprous chloride and copper dimethyldithiocarbamate; phenothiazines N, N′-diphenyl-p-phenylenediamine, phenyl-β-naphthylamine, N, N′-di-β-naphthyl-p-phenylenediamine, N-phenyl-N′-isopropyl-p-phenylenediamine, etc. Amino compounds; 1,4-dihydroxy-2 Examples include hydroxyamine compounds such as 2,6,6-tetramethylpiperidine, 1-hydroxy-2,2,6,6-tetramethylpiperidine, 4-hydroxy-2,2,6,6-tetramethylpiperidine. However, the present invention is not limited to such examples. These polymerization inhibitors may be used alone or in combination of two or more.

  The amount of the polymerization inhibitor per 100 parts by mass of the acrylic acid alkyl ester is preferably 0.001 part by mass or more, more preferably 0.005 part by mass or more, further preferably from the viewpoint of suppressing the polymerization of the alkyl acrylate ester. From the viewpoint of increasing the purity of 4-hydroxybutyl acrylate, it is preferably 5 parts by mass or less, more preferably 3 parts by mass or less, and still more preferably 1 part by mass or less.

  When 1,4-butanediol and an acrylic acid alkyl ester are transesterified, an organic solvent can be used.

  The organic solvent is preferably an organic solvent that is inert in the reaction system of the transesterification reaction. Suitable organic solvents include, for example, aliphatic hydrocarbon compounds such as n-hexane, n-heptane and n-octane, alicyclic hydrocarbon compounds such as cyclohexane and methylcyclohexane, and aromatics such as benzene, toluene and xylene. Examples include hydrocarbon compounds, ether compounds such as tetrahydrofuran, organic chlorine compounds such as dichloromethane and 1,1-dichloroethane, aromatic nitro compounds such as nitrobenzene, organic phosphorus compounds such as triethyl phosphate, and organic sulfur compounds such as dimethyl sulfoxide. However, the present invention is not limited to such examples. These organic solvents may be used alone or in combination of two or more.

  Although the quantity of an organic solvent is not specifically limited, Usually, what is necessary is just about 5-200 mass parts per 100 mass parts of total amounts of 1, 4- butanediol and acrylic acid alkylester.

  From the viewpoint of increasing the reaction rate, the reaction temperature at the time of carrying out the transesterification reaction between 1,4-butanediol and alkyl acrylate is preferably 30 ° C. or higher, more preferably 50 ° C. or higher. From the viewpoint of preventing polymerization of hydroxybutyl acrylate, the temperature is preferably 150 ° C. or lower.

  From the viewpoint of preventing the polymerization of the alkyl acrylate, the atmosphere during the transesterification reaction of 1,4-butanediol and the alkyl acrylate is preferably an atmosphere containing oxygen, which increases safety. From the viewpoint, it is more preferable that the oxygen concentration is 5% by volume to an atmospheric concentration gas. Moreover, the pressure of the atmosphere should just be atmospheric pressure normally, However, Pressurization or pressure reduction may be sufficient. For example, when the pressure of the atmosphere is reduced, the reflux temperature can be lowered, so that there is an advantage that side reactions can be suppressed.

  The reaction time for the transesterification reaction between 1,4-butanediol and acrylic acid alkyl ester depends on the amount of 1,4-butanediol and acrylic acid alkyl ester, reaction temperature, etc. In general, the time until the transesterification reaction is completed is selected. The end point of the transesterification reaction between 1,4-butanediol and alkyl acrylate can be confirmed, for example, by gas chromatography, liquid chromatography, or the like.

  The transesterification reaction between 1,4-butanediol and alkyl acrylate can be performed using, for example, a rectification column, a fluidized bed, a fixed bed, a reactive distillation column, etc., but the present invention is only such examples. It is not limited to. Further, the transesterification reaction between 1,4-butanediol and acrylic acid alkyl ester may be carried out by either a flow system or a batch system.

  Alcohol is by-produced with the progress of the transesterification reaction between 1,4-butanediol and alkyl acrylate. The by-produced alcohol is usually preferably removed from the reaction system in order to advance the reaction. By-product alcohol can be removed out of the reaction system, for example, as an acrylate ester or an azeotrope with a suitable solvent.

  After transesterification of 1,4-butanediol and alkyl acrylate, the organic solvent used in the reaction, unreacted acrylate and alcohol were distilled off from the resulting reaction mixture. The compound, hydroxybutyl alcohol, can be recovered. Removal of unreacted acrylic ester and alcohol from the reaction mixture can be performed by an extraction treatment.

  More specifically, the produced 4-hydroxybutyl acrylate comprises, for example, a reaction mixture obtained by transesterifying 1,4-butanediol and an alkyl acrylate ester with water and an aliphatic hydrocarbon compound. After mixing with the extraction solvent containing, and extracting 4-hydroxybutyl acrylate into the aqueous layer, the aqueous layer and the extraction solvent containing the aromatic hydrocarbon compound are mixed and contained in the aqueous layer It can be recovered by extracting 4-hydroxybutyl acrylate into an aromatic hydrocarbon compound.

  When the reaction mixture is mixed with an extraction solvent containing water and an aliphatic hydrocarbon compound, 4-hydroxybutyl acrylate contained in the reaction mixture is extracted into an aqueous layer, and 1,4-butane as a by-product is extracted. Since diol diacrylate and the like can be extracted into the aliphatic hydrocarbon compound layer, the aqueous layer containing 4-hydroxybutyl acrylate can be recovered by separating the aqueous layer from the aliphatic hydrocarbon compound layer. it can.

  Examples of the aliphatic hydrocarbon compound include aliphatic hydrocarbon compounds having 6 to 12 carbon atoms such as cyclohexane, n-hexane, n-heptane, n-octane, n-decane, isohexane, isooctane, and isodecane. However, the present invention is not limited to such examples. In addition, in this-application specification, an aliphatic hydrocarbon compound is a thing of the concept including what has alicyclic structures, such as cyclohexane, for example. The extraction solvent containing water and an aliphatic hydrocarbon compound may contain an aromatic hydrocarbon compound as long as the object of the present invention is not impaired.

  In the extraction solvent, since the amount of the aliphatic hydrocarbon compound and water varies depending on the amount of the reaction mixture and the like, and cannot be determined unconditionally, the 4-hydroxybutyl acrylate contained in the reaction mixture is added to the aqueous layer. It is preferable to appropriately adjust the amount suitable for separating the aliphatic hydrocarbon compound layer and the aqueous layer. Moreover, the temperature at the time of performing the said extraction operation is although it does not specifically limit, Usually, it is preferable that it is about 5-50 degreeC.

  In addition, after mixing a reaction mixture and the extraction solvent containing water and an aliphatic hydrocarbon compound, and extracting 4-hydroxybutyl acrylate to an aqueous layer, it is preferable to make the said aqueous layer contact with ion-exchange resin. . Thus, when the said water layer is made to contact with an ion exchange resin, 4-hydroxybutyl acrylate with a much lower content rate of an acid component can be obtained.

  Examples of the ion exchange resin include an anion exchange resin having a basic group based on a quaternary ammonium salt, an acidic cation exchange resin having an acid group based on an acid such as phosphoric acid, carboxylic acid, and sulfonic acid. The invention is not limited to such examples. Examples of anion exchange resins include strongly basic anion resins, weakly basic anion resins, and mixtures of strongly basic cation resins and strongly basic anion resins, but the present invention is limited only to such examples. is not. Examples of acidic ion exchange resins include strongly acidic cation resins, weakly acidic cation resins, and mixtures of strongly acidic cation resins and strongly basic anion resins. However, the present invention is limited only to such examples. is not. Among these ion exchange resins, anion exchange resins are preferable from the viewpoint of obtaining 4-hydroxybutyl acrylate having a much lower acid component content.

  The amount of ion exchange resin varies depending on the type of the ion exchange resin and cannot be determined unconditionally. However, it is usually about 0.0001 to 0.1 volume times the amount of the aqueous layer in contact with the ion exchange resin. Is preferred.

  Next, by mixing the aqueous layer from which 4-hydroxybutyl acrylate has been extracted with an extraction solvent containing an aromatic hydrocarbon compound, 4-hydroxybutyl acrylate contained in the aqueous layer is aromatic carbonized. By extracting to the hydrogen compound layer and separating the aromatic hydrocarbon compound layer from the aqueous layer, the aromatic hydrocarbon compound layer containing 4-hydroxybutyl acrylate can be recovered.

  Examples of the aromatic hydrocarbon compound include benzene, ethylbenzene, toluene, xylene, and the like, but the present invention is not limited to such examples. The extraction solvent containing the aromatic hydrocarbon compound may contain an aliphatic hydrocarbon compound, water and the like within a range not impairing the object of the present invention.

  Since the amount of the aromatic hydrocarbon compound varies depending on the amount of the aqueous layer separated from the aliphatic hydrocarbon compound layer and the like, it cannot be unconditionally determined. It is preferable to appropriately adjust the amount suitable for extracting butyl acrylate into the aromatic hydrocarbon compound layer and separating the aromatic hydrocarbon compound layer and the aqueous layer. Although the temperature at the time of performing said extraction operation is not specifically limited, Usually, it is preferable that it is about 5-50 degreeC.

  The 4-hydroxybutyl acrylate contained in the aromatic hydrocarbon compound layer can be recovered, for example, by removing the aromatic hydrocarbon compound by a method such as evaporation of the aromatic hydrocarbon compound. Although the temperature at the time of removing the aromatic hydrocarbon compound contained in the aromatic hydrocarbon compound layer is not particularly limited, it is usually preferably about 20 to 150 ° C. The 4-hydroxybutyl acrylate recovered as described above may be highly purified by distillation purification, washing or the like, if necessary.

  On the other hand, the aliphatic hydrocarbon compound layer contains by-produced 1,4-butanediol diacrylate, but also contains dialkyltin oxide in addition to the 1,4-butanediol diacrylate. Therefore, from the viewpoint of effective utilization of dialkyltin oxide, dialkyltin oxide may be recovered from the aliphatic hydrocarbon compound layer by a method such as distillation, concentration, or washing.

  In the present invention, since the recovered dialkyltin oxide is maintained without much deactivation, the transesterification catalyst is used when the 1,4-butanediol is transesterified with the acrylic acid alkyl ester. Can be reused as Therefore, the recovered dialkyltin oxide is reused as a transesterification catalyst in the transesterification reaction of 1,4-butanediol and alkyl acrylate, and 1,1 in the presence of the recovered dialkyltin oxide. 4-Butanediol and an acrylic acid alkyl ester can be transesterified. At that time, the recovered dialkyltin oxide has a water content of 1000 ppm or less in the reaction system when 1,4-butanediol and the alkyl acrylate are transesterified from the viewpoint of maintaining catalytic activity. It is preferable to reuse after drying.

  Thus, according to the method for producing 4-hydroxybutyl acrylate of the present invention, the recovered dialkyltin oxide can be used repeatedly until its catalytic activity is deactivated. The production method of acrylate is excellent in industrial productivity.

  The 4-hydroxybutyl acrylate recovered as described above may be highly purified by distillation purification, washing or the like, if necessary.

  According to the production method of the present invention, 4-hydroxybutyl acrylate having a content of acrylic acid as an acid component of 50 ppm or less, preferably 30 ppm or less, more preferably 15 ppm or less can be produced. Accordingly, the 4-hydroxybutyl acrylate has a low content of acrylic acid, which is an acid component, and therefore has low skin irritation and is unlikely to cause irritation or inflammation. For example, a medical adhesive such as a poultice It is useful as a raw material for coating materials for electronic materials, photosensitive resin compositions and the like.

  Next, the present invention will be described in more detail based on examples. However, the present invention is not limited to such examples.

Example 1
A 20-liter Oldshaw, reflux condenser and air inlet tube were attached to a 2 L glass 4-necked flask, and 675 g (7.5 mol) of 1,4-butanediol and 430.45 g of methyl acrylate were placed in the flask. (5.0 mol), 100 g of cyclohexane and 0.72 g of phenothiazine as a polymerization inhibitor were added, 3.61 g of dioctyltin oxide was added to the flask, and nitrogen gas containing 7% by volume of oxygen gas was added at 20 mL / min. The reaction mixture was obtained by reacting 1,4-butanediol and methyl acrylate for 10 hours at a temperature of 85 ° C. while blowing at a flow rate of 5 ° C. When the components excluding the solvent were analyzed from the obtained reaction mixture by gas chromatography, the content of 4-hydroxybutyl acrylate was 50.9% by mass, the content of 1,4-butanediol was 37.9% by mass, The content of 1,4-butanediol diacrylate was 11.2% by mass.

  Next, the produced azeotrope of methanol and cyclohexane was placed in a decanter, 50 mL of water was continuously added to the decanter, and 1,4 until the methanol distills almost completely while removing the separated aqueous methanol solution from the decanter. -Butanediol and methyl acrylate were reacted at a temperature of 85 ° C. After completion of the reaction between 1,4-butanediol and methyl acrylate, the resulting reaction solution was heated to 88 ° C., and cyclohexane and unreacted methyl acrylate were distilled off azeotropically, thereby yielding 1088 g of the reaction mixture. Obtained.

  As a first extraction operation, 1088 g of the reaction mixture obtained above from the upper part of a pulsation type continuous extraction tower (a packed tower having a diameter of 25 mm and a length of 1.4 m) was added at a flow rate of 50 mL / hr and pure water was supplied at 29. By supplying at a flow rate of 5 mL / hr, cyclohexane is supplied from the lower part of the continuous extraction column at a flow rate of 87.8 mL / hr over 22 hours, and the inside of the column is heated to 30 to 35 ° C. and continuously extracted. A cyclohexane layer containing the produced 1,4-butanediol diacrylate and an aqueous layer containing the produced 4-hydroxybutyl acrylate and unreacted 1,4-butanediol were obtained.

  As the second extraction operation, 1200 mL of the aqueous layer obtained above was supplied from the upper part of the continuous extraction tower at a flow rate of 50 mL / hr, and toluene was extracted from the lower part of the continuous extraction tower as an extraction solvent at a flow rate of 87.5 mL / hr. Supply over time. The inside of the tower was heated to 35 to 40 ° C. and continuously extracted to obtain a toluene layer containing 4-hydroxybutyl acrylate and an aqueous layer containing 1,4-butanediol. When the content of 1,4-butanediol diacrylate in components other than toluene contained in the toluene layer was examined by gas chromatography, the content was 0.11% by mass.

  Next, 1400 g of the toluene layer obtained by the second extraction operation was charged into a 2 L glass three-necked flask, 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask, and the bottom of the flask was The temperature was adjusted to 74 to 85 ° C., and toluene was distilled off at a reduced pressure of 280 to 20 hPa for 14 hours to concentrate 4-hydroxybutyl acrylate. Next, when the concentrate obtained was distilled with a thin film distiller and the acid content of the distillate was measured, the acrylic acid content in the distillate was 0.0065% by mass (65 ppm).

Example 2
A 20-liter Oldshaw, reflux condenser and gas inlet tube were installed in a 2 L glass 4-neck flask, 675 g of 1,4-butanediol, 430.45 g (5.0 mol) of methyl acrylate, and 100 g of cyclohexane. Then, after adding 0.72 g of phenothiazine as a polymerization inhibitor, 3.00 g of dioctyltin oxide was added into the flask, and nitrogen gas containing 7% by volume of oxygen gas was blown in at a flow rate of 20 mL / min while 1,4- Butanediol and methyl acrylate were reacted at a temperature of 85 ° C. for 10 hours.

  The produced azeotrope of methanol and cyclohexane is placed in a decanter, 50 mL of water is continuously added to the decanter, and 1,4-butanediol is removed until almost no methanol is distilled while removing the separated aqueous methanol solution from the decanter. And methyl acrylate were reacted at a temperature of 85 ° C.

  After completion of the reaction between 1,4-butanediol and methyl acrylate, the reaction solution obtained was heated to 80 ° C. under reduced pressure, and cyclohexane and unreacted methyl acrylate were distilled off to obtain 1080 g of the reaction mixture. Obtained.

  Next, as a first extraction operation, 1080 g of the reaction mixture obtained above from the upper part of a pulsation type continuous extraction tower (a packed tower having a diameter of 25 mm and a length of 1.4 m) is added at a flow rate of 50 mL / hr and pure water is added. By supplying at a flow rate of 29.5 mL / hr, supplying cyclohexane from the bottom of the continuous extraction tower at a flow rate of 87.8 mL / hr over 22 hours, heating the inside of the tower to 30 to 35 ° C., and continuously extracting A cyclohexane layer containing 1,4-butanediol diacrylate as a by-product and a water layer containing 4-hydroxybutyl acrylate and unreacted 1,4-butanediol were obtained.

  As the second extraction operation, 1200 mL of the aqueous layer obtained above was supplied from the upper part of the continuous extraction tower at a flow rate of 50 mL / hr, and toluene was extracted from the lower part of the continuous extraction tower as an extraction solvent at a flow rate of 87.5 mL / hr. Supply over time. The inside of the tower was heated to 35 to 40 ° C. and continuously extracted to obtain a toluene layer containing 4-hydroxybutyl acrylate and an aqueous layer containing 1,4-butanediol. When the content of 1,4-butanediol diacrylate in components other than toluene contained in the toluene layer was examined by gas chromatography, the content was 0.10% by mass.

  Next, 1400 g of the toluene layer obtained by the second extraction operation was charged into a 2 L glass three-necked flask, and 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask. The temperature at the bottom was adjusted to 74-85 ° C., and 4-hydroxybutyl acrylate was concentrated by distilling off toluene under reduced pressure of 280-20 hPa for 14 hours.

  Next, 1400 g of the toluene layer obtained by the second extraction operation was charged into a 2 L glass three-necked flask, 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask, and the bottom of the flask was The temperature was adjusted to 74 to 85 ° C., and toluene was distilled off at a reduced pressure of 280 to 20 hPa for 14 hours to concentrate 4-hydroxybutyl acrylate. Next, when the concentrate obtained was distilled with a thin-film distiller and the acid content of the distillate was measured, the acrylic acid content in the distillate was 0.0076 mass% (76 ppm).

Example 3
A 20-liter Oldshaw, reflux condenser and gas inlet tube were installed in a 2 L glass 4-neck flask, 675 g of 1,4-butanediol, 430.45 g (5.0 mol) of methyl acrylate, and 100 g of cyclohexane. Then, 0.72 g of phenothiazine was charged as a polymerization inhibitor, 3.80 g of dioctyltin oxide was added to the flask, and nitrogen gas containing 7% by volume of oxygen gas was blown in at a flow rate of 20 mL / min while 1,4- Butanediol and methyl acrylate were reacted at a temperature of 85 ° C. for 5 hours.

  The produced azeotrope of methanol and cyclohexane is placed in a decanter, 50 mL of water is continuously added to the decanter, and 1,4-butanediol is removed until almost no methanol is distilled while removing the separated aqueous methanol solution from the decanter. And methyl acrylate were reacted at a temperature of 85 ° C.

  After completion of the reaction between 1,4-butanediol and methyl acrylate, the reaction solution obtained was heated to 88 ° C., and unreacted methyl acrylate was distilled off by azeotropy with cyclohexane, whereby 1109 g of reaction mixture was obtained. Got.

  Next, as a first extraction operation, 1109 g of the reaction mixture obtained above from the upper part of a pulsation type continuous extraction tower (a packed tower having a diameter of 25 mm and a length of 1.4 m) is added at a flow rate of 50 mL / hr and pure water is added. By supplying at a flow rate of 29.5 mL / hr, supplying cyclohexane from the bottom of the continuous extraction tower at a flow rate of 87.8 mL / hr over 22 hours, heating the inside of the tower to 30 to 35 ° C., and continuously extracting A cyclohexane layer containing 1,4-butanediol diacrylate as a by-product and a water layer containing 4-hydroxybutyl acrylate and unreacted 1,4-butanediol were obtained.

  Next, the aqueous layer obtained above was dropped at a flow rate of 95 g / hr into a column packed with 16 g of a strongly basic anion exchange resin [manufactured by Organo Corporation, trade name: Amberlite IRA900JCL] The layer was contacted with a strongly basic cation exchange resin. Thereafter, as a second extraction operation, 1200 mL of the aqueous layer obtained above is supplied at a flow rate of 50 mL / hr from the upper part of the continuous extraction tower, and toluene is supplied as an extraction solvent from the lower part of the continuous extraction tower at a flow rate of 87.5 mL / hr. For 24 hours. The inside of the tower was heated to 35 to 40 ° C. and continuously extracted to obtain a toluene layer containing 4-hydroxybutyl acrylate and an aqueous layer containing 1,4-butanediol. When the content of 1,4-butanediol diacrylate in components other than toluene contained in the toluene layer was examined by gas chromatography, the content was 0.12% by mass.

  Next, 1400 g of the toluene layer obtained by the second extraction operation was charged into a 2 L glass three-necked flask, and 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask. The temperature at the bottom was adjusted to 74-85 ° C., and 4-hydroxybutyl acrylate was concentrated by distilling off toluene under reduced pressure of 280-20 hPa for 14 hours.

  1400 g of the toluene layer obtained by the second extraction operation was charged into a 2 L glass three-necked flask, 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask, and the temperature at the bottom of the flask was set to 74. The 4-hydroxybutyl acrylate was concentrated by adjusting the temperature to ˜85 ° C. and distilling off the toluene for 14 hours at a degree of vacuum of 280-20 hPa. Next, when the concentrate obtained was distilled with a thin-film distiller and the acid content of the distillate was measured, the acrylic acid content in the distillate was 0.0013% by mass (13 ppm).

  From the results of Example 3, dioctyltin oxide was used as the transesterification catalyst, and 4-hydroxybutyl acrylate having an acrylic acid content of 15 ppm or less was efficiently obtained by contacting the aqueous layer with a basic ion exchange resin. It can be seen that it can be manufactured.

Example 4
By concentrating the aqueous layer obtained by the second extraction operation of Example 1, 340 g of a mixture of 1,4-butanediol and dioctyltin oxide was recovered.

  Next, instead of 1,4-butanediol used in Example 1, 340 g of the mixture recovered above was charged, and the same amount as 1,4-butanediol used in Example 1 was added. Was charged with new 1,4-butanediol. At that time, since the mixture contained dialkyltin oxide, no transesterification catalyst was newly added.

  Thereafter, in the same manner as in Example 1, 1,4-butanediol and methyl acrylate were reacted at a temperature of 85 ° C. for 10 hours.

  After completion of the reaction between 1,4-butanediol and methyl acrylate, the resulting reaction solution was heated to 88 ° C. under reduced pressure, and unreacted methyl acrylate was distilled off to obtain 1080 g of a reaction mixture. .

  When the component except the solvent was analyzed by gas chromatography from the reaction mixture obtained above, the content of 4-hydroxybutyl acrylate in the component was 50.1% by mass, and the content of 1,4-butanediol was The content of 37.3% by mass and 1,4-butanediol diacrylate was 12.2% by mass.

  As a first extraction operation, 1088 g of the reaction mixture obtained above from the upper part of a pulsation type continuous extraction tower (a packed tower having a diameter of 25 mm and a length of 1.4 m) was added at a flow rate of 50 mL / hr and pure water was supplied at 29. By supplying at a flow rate of 5 mL / hr, cyclohexane is supplied from the lower part of the continuous extraction column at a flow rate of 87.8 mL / hr over 22 hours, and the inside of the column is heated to 30 to 35 ° C. and continuously extracted. A cyclohexane layer containing the produced 1,4-butanediol diacrylate and an aqueous layer containing the produced 4-hydroxybutyl acrylate and unreacted 1,4-butanediol were obtained.

  The aqueous layer obtained above was dropped into a column packed with 16 g of weakly basic anion exchange resin [manufactured by Organo Corporation, trade name: Amberlite IRA98] at a flow rate of 95 g / hr. By doing so, the aqueous layer was brought into contact with the weakly basic cation exchange resin.

  Next, as a second extraction operation, 1200 mL of the aqueous layer obtained above is supplied from the upper part of the continuous extraction tower at a flow rate of 50 mL / hr, and toluene as an extraction solvent is supplied from the lower part of the continuous extraction tower at 87.5 mL / hr. It was supplied at a flow rate over 24 hours. The inside of the tower was heated to 35 to 40 ° C. and continuously extracted to obtain a toluene layer containing 4-hydroxybutyl acrylate and an aqueous layer containing 1,4-butanediol. When the content of 1,4-butanediol diacrylate in components other than toluene contained in the toluene layer was examined by gas chromatography, the content was 0.11% by mass.

  1400 g of the toluene layer obtained by the second extraction operation was charged into a 2 L glass three-necked flask, 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask, and the temperature at the bottom of the flask Was adjusted to 74 to 85 ° C., and toluene was distilled off under reduced pressure of 280 to 20 hPa for 14 hours to concentrate 4-hydroxybutyl acrylate.

  The components contained in the concentrate obtained above were analyzed by gas chromatography. As a result, 98.3% by mass of 4-hydroxybutyl acrylate and 0.11% by mass of 1,4-butanediol diacrylate were contained in the components. And 1.2% by weight of 1,4-butanediol. Next, when the concentrate obtained was distilled with a thin-film distiller and the acid content of the distillate was measured, the acrylic acid content in the distillate was 0.0015% by mass (15 ppm).

  From the above results, it can be seen that 4-hydroxybutyl acrylate having a low content of acidic content can be efficiently recovered even when the transesterification catalyst is reused and the extraction operation is performed.

Example 5
In Example 1, except that 6.14 g (0.025 mol) of tetramethyl titanate (purity: 70% by mass) was used as a transesterification catalyst, 1,4-butanediol and The reaction mixture was obtained by reacting with methyl acrylate at a temperature of 85 ° C. for 10 hours. The components excluding the solvent from the obtained reaction mixture were analyzed by gas chromatography. The content of 4-hydroxybutyl acrylate was 51.1% by mass, the content of 1,4-butanediol was 36.5% by mass, The content of 1,4-butanediol diacrylate was 12.4% by mass.

  Next, as a first extraction operation, 1088 g of the reaction mixture obtained above from the upper part of a pulsation type continuous extraction tower (a packed tower having a diameter of 25 mm and a length of 1.4 m) is purified water at a flow rate of 50 mL / hr. Was supplied at a flow rate of 29.5 mL / hr, and cyclohexane was supplied at a flow rate of 87.8 mL / hr from the bottom of the continuous extraction column. As a result, the reaction mixture in the continuous extraction tower became cloudy and insolubles were precipitated, so that the produced 1,4-butanediol diacrylate could not be separated from the reaction mixture.

  From the results of Examples 1 to 5, when dialkyl tin oxide, which is a tin compound, was used as the transesterification catalyst (Examples 1 to 4), in contrast to the case where tetramethyl titanate was used as the transesterification catalyst ( Example 5) It can be seen that 4-hydroxybutyl methacrylate can be easily isolated from the reaction mixture.

Comparative Example 1
In Example 1, 1,4-butanediol and methyl acrylate were reacted in the same manner as in Example 1 except that dioctyltin oxide as a catalyst was not used, and 3 hours after the start of the reaction. The amount of methanol produced was examined, but no methanol was produced, and the reaction mixture was analyzed by gas chromatography, but no production of 4-hydroxybutyl acrylate was observed.

Comparative Example 2
A 20-liter Oldshaw, reflux condenser and air inlet tube were attached to a 2 L glass 4-necked flask, and 676 g (7.5 mol) of 1,4-butanediol and 360.5 g of acrylic acid ( 5.0 mol), 400 g of cyclohexane and 0.721 g of phenothiazine as a polymerization inhibitor were added, 3.6 g of purified 98% sulfuric acid was added to the flask, and 20 mL of nitrogen gas containing 7% by volume of oxygen gas was added. 1,4-butanediol and acrylic acid are heated to a temperature of 85 ° C. while blowing at a flow rate of / min, and the produced water is removed from the system by azeotropic dehydration, and 1,4-butanediol and methyl acrylate Was reacted at a temperature of 85 ° C. for 12 hours.

  After completion of the reaction between 1,4-butanediol and methyl acrylate, the obtained reaction solution is neutralized with a 10% aqueous sodium hydroxide solution, and the first extraction operation and the second extraction operation are performed in the same manner as in Example 1. As a result, a toluene solution of 4-hydroxybutyl acrylate was obtained.

  Next, 1400 g of a 4-hydroxybutyl acrylate toluene solution (toluene layer) obtained by the second extraction operation was charged into a 2 L glass three-necked flask, and 0.008 g of hydroquinone monomethyl ether as a polymerization inhibitor was added to the flask. 4-hydroxybutyl acrylate was concentrated by adjusting the temperature at the bottom of the flask to 74 to 85 ° C. and distilling off toluene at a reduced pressure of 280 to 20 hPa for 14 hours.

  Next, when the concentrate obtained was distilled with a thin film distiller and the acid content of the distillate was measured, the acrylic acid content in the distillate was 0.075% by mass (750 ppm).

  From the result of Comparative Example 2, when acrylic acid was used instead of methyl acrylate, and 4-hydroxybutyl acrylate was produced not by transesterification but by esterification, the content of acrylic acid was greatly reduced to 50 ppm. Therefore, it can be seen that 4-hydroxybutyl acrylate having an acrylic acid content of 50 ppm or less cannot be produced.

  From the above results, 4-hydroxybutyl acrylate obtained by the production method of each Example has a low skin irritation, irritation and inflammation because the content of acrylic acid in the 4-hydroxybutyl acrylate is 50 ppm or less. Is suitable not only as a raw material for medical pressure-sensitive adhesives, but also as a raw material for coating materials for electronic materials, photosensitive resin compositions by ultraviolet curing, electron beam curing, etc. where work environment is important You can see that you can.

Claims (2)

A process for producing 4-hydroxybutyl acrylate by transesterification of 1,4-butanediol and alkyl acrylate, wherein 1,4-butanediol and alkyl acrylate are present in the presence of a transesterification catalyst. And the resulting reaction mixture and an extraction solvent containing water and an aliphatic hydrocarbon compound are mixed to extract 4-hydroxybutyl acrylate contained in the reaction mixture into an aqueous layer. The aqueous layer is brought into contact with an ion exchange resin, the aqueous layer brought into contact with the ion exchange resin and an extraction solvent containing an aromatic hydrocarbon compound are mixed, and 4-hydroxybutyl contained in the aqueous layer by extracting acrylate aromatic hydrocarbon compound, to recover 4-hydroxybutyl acrylate The process for preparing 4-hydroxy butyl acrylate, wherein the door. Reaction mixture containing 4-hydroxybutyl acrylate obtained by transesterifying 1,4-butanediol and an acrylic acid alkyl ester in the presence of the dialkyltin oxide using dialkyltin oxide as a transesterification catalyst from collected the dialkyltin oxide, according to claim 1 for reusing the recovered dialkyltin oxide and 1,4-butane diol with acrylic acid alkyl ester as an ester exchange catalyst in which an ester exchange reaction 4 -Production method of hydroxybutyl acrylate.