JP4963540B2 - 3- (Meth) acryloyloxy-4-hydroxytetrahydrofuran and process for producing the same - Google Patents

Description

  The present invention relates to high-purity 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran, which is an important compound as a highly hydrophilic polymerizable monomer, and a method for producing the same.

  In the production of vinyl polymer resins, (meth) acrylic acid esters are one of the important (co) polymerization monomers and are used in a wide variety of applications. However, polymerization with a single monomer often does not provide the desired performance. In that case, in order to obtain the required physical properties, a mixture of different (meth) acrylic acid ester monomers and copolymerization thereof are performed. Is called. Among them, imparting polarity to the resin is one of the important resin modifications, and a (meth) acrylic acid ester monomer having a polar group is used for that purpose. Typical examples thereof include linear hydroxyalkyl (meth) acrylates such as hydroxyethyl (meth) acrylate, hydroxypropyl (meth) acrylate, and hydroxybutyl (meth) acrylate. Since these can be easily produced industrially from a compound having a corresponding epoxy skeleton or a corresponding diol and (meth) acrylic acid, they are easily available in large quantities at low cost and have been widely used. However, depending on the application, hydroxy (meth) acrylates having these chain skeletons are not optimal for expressing the desired properties. Rather, although these polar polar monomers are added, these chain polar monomers are added. As a result, there was a problem that functions that were originally required were weakened or no longer developed.

  Thus, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran has been proposed as a polar monomer having a cyclic structure instead of a chain as a new compound. Since this is hydrophilic and has a heterocyclic ring, it requires a physical property induced by the heterocyclic ring, for example, a fluoride releasing dental composition (see Patent Document 1), a radiation curable resin, and the like. It is considered effective as a copolymerization monomer for the composition (see Patent Document 2).

However, as for the method for producing this 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran, since this is a novel compound, no industrially advantageous method has been found yet. And it is thought that the problem that a considerable amount of di (meth) acryloyloxytetrahydrofuran that causes a crosslinking reaction during the polymerization cannot be solved only by applying the conventional technique. Specifically, the conventional general organic compound extraction method is a method of performing post-reaction aqueous post-treatment, and then extracting and recovering the target (meth) acrylic acid ester with an organic solvent that can be extracted (non- However, the content of di (meth) acryloyloxytetrahydrofuran cannot be reduced by this method.
JP-A-8-301718 Japanese Patent Laid-Open No. 7-48422 Tetrahedron 58 (2002) 5909.

According to the study by the present inventors, the synthesis of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is carried out using 3,4-dihydroxytetrahydrofuran as a raw material, (meth) acrylic acid, (meth) acrylic acid chloride, Since it is synthesized by selective monoesterification with (meth) acrylic anhydride, not a little di (meth) acryloyloxytetrahydrofuran is by-produced. Furthermore, in the post-treatment after the reaction, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is effectively used when recovering the target 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran by extraction. Although it is necessary to use an organic solvent that can be extracted from an aqueous medium, almost all of the mixed di (meth) acryloyloxytetrahydrofuran is extracted together when extraction is performed normally using such a solvent. It is possible.

  Therefore, since a considerable amount of di (meth) acryloyloxytetrahydrofuran is mixed in 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran extracted by such a conventional method, the molecular weight is increased during the polymerization. This may cause a serious problem that it cannot be controlled as intended or that the three-dimensional structure of the polymer is different. This is due to the fact that di (meth) acryloyloxytetrahydrofuran contains two polymerizable functional groups. That is, when mixed di (meth) acryloyloxytetrahydrofuran is involved in polymerization, a polymer having a structure crosslinked by two aoacryloyllo groups is formed, and only 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is polymerized. A polymer having a higher molecular weight than that obtained is produced. For this reason, it is considered that the molecular weight distribution is widened, which may cause a difference from the designed physical properties.

  Therefore, the present invention provides high-purity 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran with a low content of di (meth) acryloyloxytetrahydrofuran that causes a crosslinking reaction during polymerization, It aims at providing the method of manufacturing this thing by the technique which can be implemented industrially.

  As a result of intensive studies to solve the above problems, (meth) acryloylation reaction was carried out in producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran by converting 3,4-dihydroxytetrahydrofuran to (meth) acryloyloyl. Thereafter, by distilling off by-product di (meth) acryloyloxytetrahydrofuran with an extraction solvent containing at least water and hydrocarbons, it is possible to produce 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran with extremely high purity. As a result, the present invention has been completed.

  That is, the first gist of the present invention is that the 3,4-dihydroxytetrahydrofuran represented by the general formula (1) is (meth) acryloylated to give 3- (meth) acryloyloxy-4- represented by the general formula (2). In producing hydroxytetrahydrofuran, after the (meth) acryloylation reaction, di (meth) acryloyloxytetrahydrofuran represented by the general formula (3) as a by-product is extracted and removed with an extraction solvent containing at least water and hydrocarbon. In the production method of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran.

(In formulas (2) and (3), R ¹ is a (meth) acryloyl group represented by the following formula (4).)

(In the formula (4), R ² is a hydrogen atom or a methyl group, the wavy line indicates the site of attachment.)
The second gist is a method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran as described above, wherein the reaction solvent used in the (meth) acryloylation reaction is an aprotic polar solvent miscible with water. Exist.
The third gist is characterized in that the content of the aprotic polar solvent miscible with water in the extraction solvent is 40% by weight or less based on the weight of water present in the extraction solvent. The production method of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran.

The fourth gist is that the aprotic polar solvent miscible with water is at least one solvent selected from ketones, ethers, nitriles, amides, and sulfoxides having 10 or less carbon atoms, and a hydrocarbon solvent. Is a method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran as described above, which is a compound having 10 or less carbon atoms.
The fifth gist is that the abundance ratio between 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran represented by the above formula (2) and di (meth) acryloyloxytetrahydrofuran represented by the above formula (3) is FID. The present invention resides in 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran, which has an area ratio of 97/3 or more when analyzed by gas chromatography with a detector.

Since the highly purified 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran of the present invention has a high hydrophilicity, it exhibits extremely good solubility in an aqueous solvent, so that it is rare when used as a polymer. Hydrophilicity can be efficiently imparted by the copolymer composition. In addition, since the content of di (meth) acryloyloxytetrahydrofuran, which makes it difficult to control the degree of polymerization during polymerization, is extremely small, a polymer can be obtained with a predetermined molecular weight distribution, and the intended physical properties can be achieved. Becomes easy. Furthermore, according to the production method of the present invention, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran can be produced in good yield by an industrially simple operation.

Hereinafter, the present invention will be described in detail.
<3- (Meth) acryloyloxy-4-hydroxytetrahydrofuran>
The highly purified 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran of the present invention is represented by the structure of the following formula (2).

(In formula (2), R ¹ is a (meth) acryloyl group represented by the following formula (4).)

(In the formula (4), R ² is a hydrogen atom or a methyl group, the wavy line indicates the site of attachment.)
Furthermore, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran according to the present invention is highly pure, and in typical cases, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran and di (meth) acryloyloxy The abundance ratio with tetrahydrofuran is 97/3 or more as an area ratio when analyzed by gas chromatography equipped with an FID detector.

  <Method for Producing 3- (Meth) acryloyloxy-4-hydroxytetrahydrofuran> The compound of the present invention, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran, includes 3,4-dihydroxytetrahydrofuran as raw materials. It is synthesized by selectively mono (meth) acryloyloxylation of one of the hydroxy groups. The raw material 3,4-dihydroxytetrahydrofuran can be synthesized by dehydrating cyclization of erythritol by a known method (for example, the method described in US Pat. No. 2,572,566).

  The selective monoesterification reaction is not particularly limited as long as it is a general esterification reaction of a hydroxyl group, and any synthesis method can be arbitrarily employed. Typical methods include esterifying a hydroxyl group using (meth) acrylic acid halide, transesterification using a lower alcohol ester of (meth) acrylic acid, (meth) acrylic acid and 3,4 -Direct esterification reaction of dehydrating condensation with dihydroxytetrahydrofuran, etc. are preferably used.

  The compound of the present invention and the reaction reagent are (meth) acrylic acid compounds and are highly polymerizable. Therefore, a polymerization inhibitor may be used as necessary so that polymerization does not proceed during reaction or storage. Examples of polymerization inhibitors include hydroquinones such as p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, 2,5-diphenylparabenzoquinone, and N-oxy such as tetramethylpiperidinyl-N-oxy radical. Examples thereof include radicals, phenothiazine, diphenylamine, phenyl-β-naphthylamine, nitrosobenzene, picric acid, molecular oxygen, sulfur, and copper (II) chloride.

The amount of the polymerization inhibitor used is 3,4-dihydroxytetrahydrofuran or the product of the general formula (2) compound, the lower limit is usually 10 ppm or more, preferably 50 ppm or more, and the upper limit is usually 10000 ppm. Hereinafter, it is preferably 1000 ppm or less.
The typical reaction conditions that can be adopted for the typical (meth) acryloylation reaction of 3,4-dihydroxytetrahydrofuran are described below, but it is possible to produce 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran. If there is, it is not limited to this.

<Method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran; transesterification method>
A compound that can be used as a (meth) acryloylating agent in the case of (meth) acrylate-converting 3,4-dihydroxytetrahydrofuran by transesterification is a lower alcohol ester of (meth) acrylic acid. The lower alcohol is preferably a C1-C4 aliphatic alcohol, and the number of alcohol residues is selected from 1 to 3. Particularly preferred are (meth) acrylic acid methyl ester, ethyl ester, n-propyl ester and i-propyl ester.

In this case, the lower alcohol ester of (meth) acrylic acid is used at a lower limit of usually 0.1 mol equivalent or more, preferably 0.2 mol equivalent or more, relative to the number of moles of the raw material 3,4-dihydroxytetrahydrofuran. More preferably, it is 0.5 mol equivalent or more, and the upper limit is usually 20 mol equivalent or less, preferably 10 mol equivalent or less, more preferably 5 mol equivalent or less.
These are methods for adding the lower alcohol ester of (meth) acrylic acid, but there is no particular limitation. It is possible to carry out the reaction by adding the total amount of 3,4-dihydroxytetrahydrofuran to the reaction when charging the reaction. It is also possible to add them together.

  The reaction can be carried out without solvent or using a solvent. When using a solvent, the solvent to be used is not particularly limited, but an aromatic hydrocarbon solvent such as toluene and xylene, an aliphatic hydrocarbon solvent such as hexane and heptane, diethyl ether, tetrahydrofuran, monoethylene glycol dimethyl ether, diethylene glycol Ether solvents such as dimethyl ether, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, butyl acetate and gamma butyrolactone, amide solvents such as dimethylformamide, dimethylacetamide and N-methylpyrrolidone, Alkyl nitrile solvents such as acetonitrile and propionitrile are preferably used. These solvents may be used alone, or a plurality of arbitrary solvents may be mixed and used.

When a solvent is used, the amount is such that the concentration of 3,4-dihydroxytetrahydrofuran as a raw material is such that the lower limit is usually 0.1% or higher, preferably 1% or higher, and the upper limit is not particularly limited. The amount is usually 80% or less, preferably 50% or less.
The transesterification reaction is usually performed in the presence of a catalyst. As a usable catalyst, a Lewis acid or an alkali compound which can be generally used in a transesterification reaction can be applied. For example, alkoxy transition metal compounds such as titanium tetraisopropoxide, alkali metal or alkaline earth metal alcoholates such as sodium methoxide, aluminum alkoxides such as aluminum triisopropoxide, alkalis such as lithium hydroxide and sodium hydroxide Examples thereof include metal and alkaline earth metal hydroxides, tin compounds such as dibutyltin oxide and dioctyltin oxide. Among these, more preferred are alkoxy transition metal compounds and metal alcoholates.

The amount of these catalysts used is such that the lower limit is usually 0.01 mol% or more, preferably 0.1 mol% or more, more preferably 0.5 mol% or more with respect to the number of moles of 3,4-dihydroxytetrahydrofuran as a raw material. The upper limit is usually 50 mol% or less, preferably 20 mol% or less, and more preferably 10 mol% or less.
The reaction is preferably carried out in a reactor equipped with a normal stirring device. Alternatively, the reaction may be carried out while distilling off the alcohol generated during the reaction while transferring the equilibrium to the production system. At this time, if the (meth) acrylic acid ester used as the reagent and the alcohol azeotropes and the (meth) acrylic acid ester is removed from the system, the (meth) acrylic acid ester is sequentially added as necessary. You may replenish and react.

The reaction temperature may be carried out by heating in order to obtain a sufficient reaction rate. Specifically, the lower limit is usually 20 ° C. or higher, preferably 40 ° C. or higher, and the upper limit is usually 200 ° C. or lower, preferably 150 ° C. or lower.
The reaction time is arbitrarily selected, but as the reaction proceeds, alcohol is generated. Therefore, it is preferable to continue the reaction until no alcohol is generated. In general reaction time, the lower limit is usually 10 minutes or longer, preferably 30 minutes or longer, and the upper limit is not particularly limited, but is usually 50 hours or shorter, preferably 30 hours or shorter.

<Method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran; (meth) acrylic acid halide method>
3,4-Dihydroxytetrahydrofuran can be (meth) acryloylated using (meth) acrylic acid halide as a (meth) acryloylating agent. The compounds that can be used as the (meth) acrylic acid halide in that case are chloride, bromide, and iodide of (meth) acrylic acid.

The lower limit of the amount of (meth) acrylic acid halide used relative to the number of moles of the starting 3,4-dihydroxytetrahydrofuran is usually 0.01 molar equivalents or more, preferably 0.05 molar equivalents or more, more preferably 0.8. The upper limit is usually 20 molar equivalents or less, preferably 10 molar equivalents or less, more preferably 5 molar equivalents or less.
Although these (meth) acrylic acid halides are added, there is no particular limitation on the addition method so long as direct contact with a basic substance for a long time before the reaction is avoided. For example, 3,4-dihydroxytetrahydrofuran and (meth) acrylic acid halide may be charged into the reactor at the same time, and a basic substance may be added later, or the basic substance previously charged in the reactor and 3,4-dihydroxy may be added. You may react by dripping (meth) acrylic acid halide to the mixture of tetrahydrofuran, or its mixed solution.

  When the reaction is carried out using an acid halide, it is necessary to appropriately control the water content. If water is present in the system, the acid halide is decomposed, so that the reagent cannot be used effectively. The substrate used in the present invention, 3,4-dihydroxytetrahydrofuran, is a compound that is easily miscible with water, but the smaller the amount of water contained in the substrate, the better. Specifically, it is 10 mol% or less, preferably 5 mol% or less, more preferably 1 mol% or less with respect to 3,4-dihydroxytetrahydrofuran.

The reaction can be carried out without solvent or using a solvent. When the solvent is used, there is no particular limitation on the usable solvent, but aromatic hydrocarbon solvents such as toluene and xylene, aliphatic hydrocarbon solvents such as hexane and heptane, diethyl ether, tetrahydrofuran, monoethylene glycol dimethyl ether, Ether solvents such as diethylene glycol dimethyl ether, ketone solvents such as acetone, methyl ethyl ketone and methyl isobutyl ketone, ester solvents such as ethyl acetate, butyl acetate and gamma butyrolactone, sulfoxide solvents such as dimethyl sulfoxide, dimethylformamide and dimethylacetamide, N An amide solvent such as methylpyrrolidone or an alkyl nitrile solvent such as acetonitrile or propionitrile is preferably used. These solvents may be used alone, or a plurality of arbitrary solvents may be mixed and used.

When a solvent is used, the amount is such that the concentration of 3,4-dihydroxytetrahydrofuran as a raw material is such that the lower limit is usually 0.1% or higher, preferably 1% or higher, and the upper limit is not particularly limited. The amount is usually 80% or less, preferably 50% or less.
The (meth) acryloylation reaction with (meth) acrylic acid halide is usually carried out in the presence of a basic substance. Usable basic substances include inorganic bases such as sodium hydroxide, sodium hydrogen carbonate, sodium carbonate and potassium carbonate, basic ion exchange resins, organic tertiary amines such as triethylamine and tributylamine, and aromatics such as pyridine. An amine or the like can be used. Usually, pyridine, triethylamine and the like are often used in the esterification reaction of an alcohol with an acid halide, but in the present invention, an inorganic base such as potassium carbonate is also preferably used. When an inorganic base is used, there is a feature that the reaction system and the product are less colored, and this is extremely effective for applications where coloring is not preferred.

  When an inorganic base is used, it is preferable to use an aprotic polar solvent as the solvent. Furthermore, an aprotic polar solvent miscible with water is preferable. This is to increase the solubility of the inorganic base used to obtain a practical reaction rate. Examples of aprotic polar solvents miscible with water include ketone solvents such as acetone and methyl ethyl ketone, organic nitrile solvents such as acetonitrile, amide solvents such as N, N-dimethylformamide, dimethyl sulfoxide and the like. Examples thereof include sulfoxide solvents.

Although it is the usage-amount of these basic substances, with respect to the (meth) acrylic acid halide used, the lower limit is usually 0.1 mole equivalent, preferably 0.5 mole equivalent or more, more preferably 1 mole, etc. The upper limit is usually 10 mol equivalent or less, preferably 5 mol equivalent or less, more preferably 2 mol equivalent or less.
The reaction is preferably carried out in a reactor equipped with a normal stirring device.

The reaction temperature adopted is carried out in the range where the lower limit is usually −50 ° C. or higher, preferably −20 ° C. or higher, and the upper limit is usually 70 ° C. or lower, preferably 50 ° C. or lower, more preferably 30 ° C. or lower.
The reaction time is arbitrarily selected, but the lower limit including the dropping time of the reaction time reagent is usually 10 minutes or more, preferably 30 minutes or more, and the upper limit is not particularly limited, but is usually 20 hours or less, preferably 10 hours or less. It is.

In addition, when performing the (meth) acryloylation reaction by a (meth) acrylic acid halide, it is necessary to pay attention to the purity of the (meth) acrylic acid halide to be used. (Meth) acrylic acid halides are described in Chimia, (Switzerland), 1985, 39, p. As described in 19-20, it is characterized by dimerization with time and purity. The purity of the target product can be increased by using a reagent having a smaller amount of these dimers. Specifically, a (meth) acrylic acid halide having a purity of usually 80 mol% or more, preferably 85 mol% or more, more preferably 90 mol% or more, and even more preferably 95 mol% or more is used.
The method for increasing the purity of the (meth) acrylic acid halide is not particularly limited, but it is convenient and preferable to carry out distillation using the boiling point difference between the acid halide and the dimer. As the distillation method, simple distillation, precision distillation, thin film distillation and the like can be employed without limitation.

<Production method of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran; direct dehydration method>
When esterifying with (meth) acrylic acid, the reaction proceeds rapidly when a dehydrating condensing agent is allowed to coexist. As the condensing agent, any condensing agent generally known for esterification can be used without particular limitation. For example, N, N′-dicyclohexylcarbodiimide, 2-chloro-1,3-dimethylimidazolium chloride can be used. Propanephosphonic anhydride is preferably used. In this case, an organic basic substance such as 4-dimethylaminopyridine or triethylamine may be used in combination. The lower limit of the reaction temperature usually employed in this reaction is usually −20 ° C., preferably −10 ° C., and the upper limit is usually 150 ° C., preferably 100 ° C.

The amount of the dehydrating condensing agent used is theoretically sufficient if it is used in an equivalent amount or more with respect to 3,4-dihydroxytetrahydrofuran as a substrate, but may be used in excess. Preferably, it is 1.0 molar equivalent or more, more preferably 1.1 molar equivalent or more.
When a dehydrating condensing agent is not used, (meth) acrylic acid and 3,4-dihydroxytetrahydrofuran are reacted in the presence of an acid while distilling off generated water.

  Any acid can be used without particular limitation as long as it is an acid used in a normal esterification reaction. For example, inorganic acids such as sulfuric acid and hydrochloric acid, p-toluenesulfonic acid, organic sulfonic acids such as methanesulfonic acid and camphorsulfonic acid, acid type ion exchange resins, Lewis acids such as fluorinated boron and ether complexes, lanthanides And water-soluble Lewis acids such as triflate. These acids may be used alone or in combination of two or more.

The minimum of the usage-amount of an acid is 0.001 mol% or more with respect to 3, 4- dihydroxytetrahydrofuran, Preferably it is 0.01 mol% or more, More preferably, it is 0.1 mol% or more. On the other hand, the upper limit is not limited and is 10 mol equivalent or less, preferably 1 mol equivalent or less.
The reaction can be carried out without solvent or using a solvent. When using a solvent, the solvent to be used is not particularly limited, but an aromatic hydrocarbon solvent such as toluene and xylene, an aliphatic hydrocarbon solvent such as hexane and heptane, diethyl ether, tetrahydrofuran, monoethylene glycol dimethyl ether, diethylene glycol Ether solvents such as dimethyl ether, halogen solvents such as methylene chloride, chloroform and carbon tetrachloride, alkyl nitrile solvents such as acetonitrile and propionitrile, and the like are preferably used. These solvents may be used alone, or a plurality of arbitrary solvents may be mixed and used.

When using a solvent, the amount of 3,4-dihydroxytetrahydrofuran as the raw material is such that the lower limit is usually 0.1% or more, preferably 1% or more, and the upper limit is not particularly limited. The amount is usually 80% or less, preferably 50% or less.
The reaction is usually carried out at or above the boiling point of the solvent used, and the reaction is carried out while distilling off the produced water.
The reaction time is arbitrarily selected, but the end point of the reaction can be recognized by measuring the amount of water produced. In general reaction time, including the dropping time of the reagent, the lower limit is usually 10 minutes or longer, preferably 30 minutes or longer, and the upper limit is not particularly limited, but is usually 20 hours or shorter, preferably 10 hours or shorter.

<Quenching and concentration method of reaction mixture>
After the synthesis is performed as described above, the reaction mixture is quenched, and when a solvent is used in the reaction, the solvent is concentrated as necessary. When an inorganic salt is generated by the reaction, a small amount of water may be added to quench the reaction reagent, the inorganic salt may be filtered, and then a predetermined amount of water may be added.

  The water to be added may contain an acid or an alkali as necessary for quenching. Examples of the acid that can be included in this case include inorganic acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid. Alkali metal hydroxides such as sodium hydroxide and potassium hydroxide, sodium carbonate, metal carbonates such as sodium hydrogen carbonate, and alkyl metal alcoholates such as sodium ethoxide can be used as the alkali. is there.

The amount of water to be added is 0.1 times or more, preferably 0.5 or more times the lower limit of 3,4-dihydroxytetrahydrofuran used as a raw material, and the upper limit is not particularly limited. Considering volumetric efficiency and the like, the weight ratio is 50 times or less, preferably 20 times weight ratio or less.
After adding water, if necessary, the reaction solvent is concentrated. During the concentration, a polymerization inhibitor may be added as necessary. Examples of polymerization inhibitors that can be used include p-benzoquinone, hydroquinone, hydroquinone monomethyl ether, t-butylcatechol, hydroquinones such as 2,5-diphenylparabenzoquinone, and N such as tetramethylpiperidinyl-N-oxy radical. -Oxy radicals, phenothiazine, diphenylamine, phenyl-β-naphthylamine, nitrosobenzene, picric acid, molecular oxygen, sulfur, copper (II) chloride, and the like.

The lower limit is usually 10 ppm or more, preferably 50 ppm or more, and the upper limit is usually 10,000 ppm or less, preferably 1000 ppm or less, based on the weight of the compound of the general formula (2) as a product. It is.
For the concentration of the solvent, either normal pressure or reduced pressure can be employed. However, since the target product has polymerizability and thermal stability is not high, vacuum concentration at a low temperature required for concentration is preferred.

  The degree of concentration is not particularly limited when a solvent immiscible with water is used in the reaction, but considering the reactor efficiency in production, the upper limit is 20 times or less in terms of the weight ratio of the residual solvent to the target product. The amount is preferably 10 times or less. The lower limit may be distilled off completely. However, this is not the case when the entire amount or a part thereof is used as a solvent for extraction and purification in which the reaction solvent is subsequently carried out.

  When an aprotic polar solvent that is miscible with water is used in the (meth) acryloylation reaction, not a few aprotic polar solvents remain in the concentrate even after concentration, but the remaining aprotic remains. The weight ratio of the polar solvent to water is important. That is, the smaller the remaining amount of the aprotic polar solvent that is miscible with water, the higher the purification efficiency and the higher the purity of the target product. Therefore, in this concentration step, concentrate as much as possible and mix with this water. It is desirable to reduce the remaining amount of the aprotic polar solvent. Specifically, it is the same amount or less, preferably 40% or less, more preferably 20% or less, based on the weight of water remaining in the system.

<Extraction method>
After the reaction solvent is concentrated, the extraction operation of the present invention is performed. In the reaction of converting 3,4-dihydroxytetrahydrofuran to (meth) acryloyl, usually di (meth) acryloyloxytetrahydrofuran is by-produced in addition to the desired 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran. The ratio depends on the reaction employed, but is usually the area ratio of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran / di (meth) acryloyloxytetrahydrofuran analyzed by gas chromatography with a FID detector. Usually, it is about 70/30 or more and 97/3 or less.

In the present invention, the by-produced di (meth) acryloyloxytetrahydrofuran is removed by extraction. At that time, the composition of the extract is important. By using this composition as the composition of the present invention, it is possible to efficiently remove by-products, and the highly purified 3- (meth) acryloyloxy-4 of the present invention. -Production of hydroxytetrahydrofuran becomes possible.
The liquid composition at the time of extraction in the present invention is a composition containing at least water and hydrocarbons in addition to the target product and by-products. When extraction is performed with this composition, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is distributed mainly in the aqueous layer, and di (meth) acryloyloxytetrahydrofuran is mainly distributed in the hydrocarbon layer. ) Acrylilooxytetrahydrofuran can be removed.

  The hydrocarbon solvent that can be used for the extraction can be freely selected, but considering the ease of handling, those having 10 or less carbon atoms are preferable. Specific examples include linear hydrocarbon solvents such as n-hexane and n-heptane, cyclic hydrocarbon solvents such as cyclohexane, and aromatic hydrocarbon solvents such as toluene and xylene. Among these, a linear hydrocarbon solvent having low solubility of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is preferable, and more specifically, n-hexane, n-heptane, and cyclohexane are preferable. The amount of the hydrocarbon solvent used is basically not limited, but in order to obtain an efficient extraction efficiency of di (meth) acryloyloxytetrahydrofuran, the lower limit is 0.01 times the weight of the aqueous layer to be extracted. Weight ratio or more, preferably 0.1 times weight ratio or less, more preferably 0.5 times weight ratio or more, particularly preferably 1 time weight ratio or more. Further, the upper limit is 100 times weight ratio or less, preferably 50 times weight ratio or less, more preferably 20 times weight ratio or more, and particularly preferably 10 times weight ratio or more for economic reasons. The extraction operation is preferably carried out by dividing an amount of the hydrocarbon solvent falling within these ranges into several times.

  Further, if the amount of water at the time of extraction is too small, the loss of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran, which is the target product, increases, whereas if it is too large, di (meth) acryloyllo is used in a hydrocarbon solvent. After removal of oxytetrahydrofuran, attention is required because the efficiency in extracting the target 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is deteriorated. The lower limit of the amount of water is preferably 0.5 times or more, preferably 1.0 times or more, more preferably more than the weight of the reaction product 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran. It is 2.0 times by weight or more, particularly preferably 3.0 times by weight or more. Moreover, an upper limit is 100 weight times or less normally, Preferably it is 50 weight times or less, More preferably, it is 20 weight times or less, Most preferably, it is 10 weight times or less. If it is not within this range, water is added or distilled off before extraction.

In addition to the hydrocarbon solvent used in the extraction, a polar solvent immiscible with water may be added. In that case, the removal efficiency of 3,4-di (meth) acryloxytetrahydrofuran can be increased.
Examples of polar solvents that are not miscible with water include ether solvents such as diethyl ether and diisopropyl ether, ketone solvents such as methyl isobutyl ketone, and ester solvents such as ethyl acetate and butyl acetate. Of these, ketone-based solvents and ester-based solvents are preferable in terms of the removal efficiency of di (meth) acryloyloxytetrahydrofuran.

A plurality of these may be used in combination with a hydrocarbon solvent. If the amount of the polar solvent immiscible with water is too large relative to the hydrocarbon solvent, attention should be paid because the target 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran is also extracted. An upper limit is 10 times or less by volume ratio with respect to the hydrocarbon solvent to be used, Preferably it is 5 times or less, More preferably, it is 3 times or less, Most preferably, it is 1 time or less. There is no lower limit and it is not necessary to use it.

  When a polar solvent miscible with water is used in the reaction, in order to extract and remove di (meth) acryloyloxytetrahydrofuran efficiently, the composition of the liquid used for extraction after solvent concentration is set as follows. That is, the content of the aprotic polar solvent miscible with water is the same or less, preferably 40% or less, more preferably 20% or less, based on the weight of water present in the system.

The extraction operation can be performed at an arbitrary temperature, but the operation may not be possible at a temperature higher than the boiling point of the hydrocarbon solvent used or lower than the melting point. Therefore, the upper limit is usually 100 ° C. or lower, preferably 50 ° C. or lower, and the lower limit is 0 ° C. or higher, preferably 10 ° C. or higher.
In the aqueous layer after extraction, 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran in which di (meth) acryloyloxytetrahydrofuran has been removed and the purity has been increased is present. This is extracted with a polar solvent that is immiscible with water. Examples of the solvent used for extraction include ether solvents such as diethyl ether and diisopropyl ether, ketone solvents such as methyl isobutyl ketone, and ester solvents such as ethyl acetate and butyl acetate. These may be used alone or in combination.

The amount of the solvent used for the extraction has a lower limit of 0.1 times or more, preferably 1 or more times the weight of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran to be extracted. The upper limit is not particularly limited, but is 100 times or less, preferably 50 times or less in view of the volumetric efficiency of manufacturing equipment. When the extracted solution is concentrated, the desired 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran can be obtained.

The 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran thus obtained has a very low content of di (meth) acryloyloxytetrahydrofuran, and the amount thereof is typically 3- (meta) ) The area ratio of acryloyloxy-4-hydroxytetrahydrofuran to di (meth) acryloyloxytetrahydrofuran is 97/3 or more, preferably 98/2 in terms of area ratio when analyzed by gas chromatography with FID detector. More preferably, it is 99.5 / 0.5 or more. Further, the higher the upper limit, the higher the purity of the resulting compound, so there is no particular limitation. This product has a feature that when it is used as a raw material for polymerization, the production of a high molecular weight product is reduced.

<Purification method>
For example, further purification of 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran produced by the reaction described above can be performed without particular limitation. For example, a distillation method or a recrystallization method. When performing distillation, the form can be arbitrarily selected from simple distillation, precision distillation, thin film distillation, molecular distillation and the like.

<How to save>
Since 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran obtained by the above extraction operation is polymerizable, it is preferably stored at room temperature or lower. Furthermore, it is more preferable to store in a refrigerator.
<Application>
The 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran obtained by the present invention is a vinyl polymer resin that can be widely used in various fields such as electronic component materials, optical applications, recording media, various curing agents, and medical materials. It can be used as a raw material monomer.

EXAMPLES Hereinafter, although an Example demonstrates this invention further in detail, this invention is not limited by a following example, unless the summary is exceeded.
<Analysis of purity by gas chromatography>
Column: TG-1 manufactured by GL Sciences Inc. 0.25 mm, 30 m, 0.25 μm
Carrier gas: Helium Detector: FID
Inlet temperature: 250 ° C
Column tank temperature: Initial temperature 50 ° C. (hold for 5 minutes)
Temperature increase rate 10 ℃ / min
Final temperature 250 ° C (20 minutes hold)
Injection volume: 0.2 μL

Reference example 1
<Synthesis of erythritan (cis-3,4-dihydroxytetrahydrofuran)>
A reaction vessel equipped with a distillation cooling unit was charged with 30.0 g (246 mmol) of erythritol and 0.50 g (2.6 mmol, 1.1 mol equivalent) of p-toluenesulfonic acid monohydrate, and the system was decompressed at 70 Pa. The reaction was started by heating in an oil bath. When 25 minutes had elapsed, erythritan, which is a cyclized product, started to be distilled, and a fraction having a distillation temperature of 105 to 107 ° C. was fractionated (18.22 g; yield 71.1%). When this was analyzed by gas chromatography, the area purity was 99.4%, and in 1H-NMR, 16 mol% H _{2 was obtained.}
It was found to contain O.

  5.03 g of the hydrous erythritan thus obtained was taken, 20 g of toluene was added, and toluene was distilled off by a rotary evaporator. This operation was repeated two more times. It dried under reduced pressure at 40 degreeC and obtained 5.00g dehydrated erythritan. When 1H-NMR was measured, it was found that the water content of this was less than 1 mol%.

Reference example 2
<Synthesis of 3-methacryloyloxy-4-hydroxytetrahydrofuran>
In a reactor in which nitrogen was passed, 30.0 g (288 mmol) of 3,4-dihydroxytetrahydrofuran (erythritan), 44 g of potassium carbonate (K ₂ CO ₃ ; 317 mmol, 1.1 eq), 225 mL of acetonitrile, 4-methoxy as a polymerization inhibitor 30 mg of phenol was charged and cooled in an ice bath so that the temperature inside the system became 5 ° C. while stirring. A solution prepared by dissolving 30.0 g of methacrylic acid chloride (288 mmol, 1.0 eq. With respect to erythritan) in 6 mL of acetonitrile was added dropwise thereto while maintaining the system temperature at 5 ° C. or lower. After completion of dropping, the mixture was stirred at 5 ° C. for 30 minutes, and then the temperature was raised to 20 ° C. and further stirred for 2 hours. After completion of the reaction, 6 mL of 5% NaHCO ₃ aqueous solution was added to the reaction solution to quench a very small amount of methacrylic acid chloride, and then the inorganic salt produced in the reaction was filtered. After adding 54 mL of 5% NaHCO ₃ aqueous solution to the obtained filtrate, it was concentrated by an evaporator to obtain 99.8 g of concentrated liquid. This was analyzed and contained 6.2% by weight acetonitrile and 50.9% by weight water. Moreover, when this solution was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran and 3,4-dimethacryloyloxytetrahydrofuran was 96.7 / 3.3. there were.
This concentrated solution was divided into 16.3 g samples and used in Examples 1 to 3 below.

Example 1
<Extraction removal of 3,4-dimethacryloyloxytetrahydrofuran>
Acetonitrile 3.3g and water 10g were added to the sample 16.3g of the reference example 2 (content of acetonitrile with respect to water is 23.7 weight%). This liquid was extracted 3 times with 10 mL of heptane to remove 3,4-dimethacrylooxytetrahydrofuran. This solution was further extracted with 20 mL of AcOEt three times, and the obtained AcOEt layer was washed twice with 8 mL of water, and the solvent was distilled off to obtain 5.2 g of a colorless oil (isolated yield from the reaction). 63%). When this oily substance was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran to 3,4-dimethacryloyloxytetrahydrofuran was 98.9 / 1.1. It was.

Example 2
<Extraction removal of 3,4-dimethacryloyloxytetrahydrofuran>
The same operation as in Example 1 was performed except that only 10 g of water was added to 16.6 g of the sample of Reference Example 2 (the content of acetonitrile in water was 5.5% by weight) to obtain 4.9 g of a colorless oily substance. (Isolated yield from reaction; 59%). When this oily substance was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran to 3,4-dimethacryloyloxytetrahydrofuran was 99.5 / 0.5. It was.

Example 3
<Extraction removal of 3,4-dimethacryloyloxytetrahydrofuran>
The same operation as in Example 1 was performed except that only 20 g of water was added to 16.6 g of the sample of Reference Example 2 (the content of acetonitrile in water was 3.6% by weight) to obtain 4.8 g of a colorless oily substance. (Isolated yield from reaction; 58%). When this oily substance was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran to 3,4-dimethacryloyloxytetrahydrofuran was 99.6 / 0.4. It was.

Comparative Example 1
<Extraction removal of 3,4-dimethacryloyloxytetrahydrofuran>
A colorless oily substance 4 was prepared in the same manner as in Example 1 except that 6.6 g of acetonitrile and 10 g of water were added to 16.6 g of the sample of Reference Example 2 (the content of acetonitrile in water was 42.2 wt%). 0.9 g was obtained (isolated yield from reaction; 59%). When this oily substance was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran to 3,4-dimethacryloyloxytetrahydrofuran was 96.8 / 3.2. It was.

  From the above results, when the content of the aprotic polar solvent miscible with water is 40% by weight or less with respect to the amount of water present in the system, the degree of polymerization is determined. It can be seen that dimethacryloyloxyoxytetrahydrofuran, which is a large fluctuation factor, is a target product that is greatly reduced.

Reference example 3
<Synthesis of 3-hydroxy-4-methacryloyloxytetrahydrofuran>
A reactor in which nitrogen was passed was charged with 104.1 g (1.0 mol) of 3,4-dihydroxytetrahydrofuran, 152.0 g of potassium carbonate (K ₂ CO ₃ ; 1.1 mol, 1.1 eq), and 780 mL of acetonitrile, and stirred. While cooling, the system temperature was 0 ° C. Into this, 104.5 g of methacrylic acid chloride (1.0 mol: 1.0 eq with respect to erythritan, stabilizer: containing phenothiazine = 1000 ppm) was added dropwise while maintaining the system temperature at 5 ° C. or lower. After completion of dropping, the mixture was stirred at 5 ° C. for 2 hours. After completion of the reaction, 20 mL of 5% NaHCO ₃ aqueous solution was added to the reaction solution to quench a very small amount of remaining methacrylic acid chloride, and then the inorganic salt produced in the reaction was filtered. The filtrate obtained was added to a 5% NaHCO ₃ aqueous solution 19.
0 mL of tetramethylpiperidinyl-N-oxide (5 mg) was added and concentrated by an evaporator to obtain 268 g of a concentrated solution. This was analyzed and contained 5 wt% acetonitrile and 50 wt% water. Moreover, when this solution was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran and 3,4-dimethacryloyloxytetrahydrofuran was 94.5 / 5.5. there were.

Example 5
<Extraction removal of 3,4-dimethacryloyloxytetrahydrofuran>
52 g of water was added to 69.9 g of the sample of Reference Example 3 (the content of acetonitrile in water was 6.7% by weight). To this solution, 52 mL of heptane and 20 ml of ethyl acetate were added, and the upper layer (heptane-ethyl acetate layer) containing 3,4-dimethacryloxytetrahydrofuran was removed by extraction. Thereafter, the lower layer (aqueous layer) was extracted three times with 80 mL of ethyl acetate, the obtained ethyl acetate layer was washed twice with 26 mL of water, and the solvent was distilled off to obtain 23.3 g of a colorless oil ( Isolated yield from reaction; 52%). When this oily substance was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran to 3,4-dimethacryloyloxytetrahydrofuran was 99.0 / 1.0. It was.

Example 6
<Extraction removal of 3,4-dimethacryloyloxytetrahydrofuran>
52 g of water was added to 69.9 g of the sample of Reference Example 3 (the content of acetonitrile in water was 6.7% by weight). The liquid was extracted by adding 52 mL of heptane and 20 ml of ethyl acetate, and the upper layer (heptane-ethyl acetate layer) was removed. The obtained lower layer (aqueous layer) was extracted again with 52 mL of heptane and 20 ml of ethyl acetate, and the upper layer (heptane-ethyl acetate layer) was removed. Thereafter, the same operation as in Example 4 was performed to obtain 18.9 g of a colorless oil (isolated yield from reaction; 42%). When this oily substance was analyzed by gas chromatography (FID detector), the area ratio of 3-methacryloyloxy-4-hydroxytetrahydrofuran to 3,4-dimethacryloyloxytetrahydrofuran was 99.7 / 0.3. It was.

Claims (3)

3,4-Dihydroxytetrahydrofuran represented by the following formula (1) is (meth) acryloylated, and di (meth) acryloyloxytetrahydrofuran represented by the following general formula (3), which is by-produced after the (meth) acryloylation reaction. By extracting with an extraction solvent containing at least water, a hydrocarbon, and an aprotic polar solvent miscible with water,
A method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran represented by the following general formula (2):
3- (meth) acryloilo, wherein the content of the aprotic polar solvent miscible with water in the extraction solvent is 40% by weight or less based on the weight of water present in the extraction solvent A method for producing oxy-4-hydroxytetrahydrofuran.
(In formulas (2) and (3), R ¹ is a (meth) acryloyl group represented by the following formula (4).)
(In the formula (4), R ² is a hydrogen atom or a methyl group, the wavy line indicates the site of attachment.)   The method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran according to claim 1, wherein the reaction solvent used in the (meth) acryloylation reaction is an aprotic polar solvent miscible with water. Aprotic polar solvent miscible with water, having 10 or less of the ketone carbon, et - ether, nitrile, at least one solvent selected from amides and sulfoxides, and hydrocarbon solvent is not more than 10 carbon atoms The method for producing 3- (meth) acryloyloxy-4-hydroxytetrahydrofuran according to claim 1, which is a compound.