JP2017171623A - Method for producing ester compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing an ester compound, in the case esterification reaction between carboxylic acid and alcohol is caused in an inert solvent using a monolith-shaped organic porous cation exchanger as a catalyst, capable of increasing an esterification rate.SOLUTION: Provided is a method for producing an ester compound where carboxylic acid and alcohol are reacted in a solvent in the presence of a monolith-shaped organic porous cation exchanger to obtain an ester compound, in which, when the monolith-shaped organic porous cation exchanger, the carboxylic acid, the alcohol and the solvent are contacted, the contact order of the carboxylic acid, the alcohol and the solvent to the monolith-shaped organic porous cation exchanger is made into the one where the alcohol is not contacted with the monolith-shaped organic porous cation exchanger before the solvent is contacted thereto.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for producing an ester compound in which an ester compound is obtained by reacting a carboxylic acid and an alcohol in a solvent in the presence of a monolithic organic porous cation exchanger as an acid catalyst.

Ester compounds are widely used as chemical products, pharmaceuticals, and fragrances. This ester compound can be obtained by reacting a carboxylic acid and an alcohol in the presence of an acid catalyst as shown in the following formula.
R ¹ COOH + R ² OH → R ¹ COOR ² + H ₂ O

  In this reaction, water is produced together with the ester compound, but the produced ester compound is simultaneously hydrolyzed by the produced water to return to the original carboxylic acid and alcohol. Since the esterification reaction is an equilibrium reaction, it has been important to allow a dehydrating agent to coexist and to remove water produced by the reaction in order to direct the reaction to the production system.

  In general, as an acid catalyst, in addition to sulfuric acid, conventionally known silica / alumina compounds such as zeolite, heteropolyacids, cation exchange resins and the like are known as solid acid catalysts. However, if a catalyst other than a cation exchange resin is used in a water-containing reaction system containing water as described above, the activity of the catalyst is remarkably reduced or dissolved in water. Therefore, it is used in a water-containing reaction system. Most of the solid acid catalysts are cation exchange resins.

  In order to increase the catalytic activity of the cation exchange resin, it is known to reduce the particle size of the cation exchange resin. However, if the particle size of the cation exchange resin is too small, handling becomes complicated. There were drawbacks.

  On the other hand, as a method for solving such drawbacks, a method using a monolithic organic porous cation exchanger as an acid catalyst can be considered. As a solid acid catalyst of such a monolithic organic porous cation exchanger, for example, disclosed in JP-A No. 2002-346392 (Patent Document 1), an average is formed between the macropores connected to each other and the walls of the macropores. It has an open cell structure with a common opening (mesopore) having a diameter of 1 to 1000 μm, a total pore volume of 1 to 50 ml / g, and a cation exchange capacity per weight in the dry state of 0.5 equivalent / or a solid acid catalyst comprising a monolithic organic porous cation exchanger in which the cation exchange groups are uniformly distributed in the organic porous cation exchanger, or disclosed in Japanese Patent No. 5268722 (Patent Document 2). The average thickness of an aromatic vinyl polymer containing 0.1 to 5.0 mol% of a crosslinked structural unit among all the structural units having a cation exchange group introduced is 1 It is a co-continuous structure consisting of a three-dimensionally continuous skeleton of 60 μm and three-dimensionally continuous pores having an average diameter of 10 to 200 μm between the skeletons, and the total pore volume is 0.5 to 10 ml. Monolithic organic porous cation exchange in which the cation exchange capacity per weight in the dry state is 1 to 6 mg equivalent / g, and the cation exchange groups are uniformly distributed in the organic porous cation exchanger The acid catalyst which consists of a body is mentioned.

  The monolithic organic porous cation exchanger has a high cation exchange group density, a large pore volume and a specific surface area, and thus exhibits a high catalytic activity and a gas comprising a raw material, a product, or a mixture thereof. Or it is excellent in the permeability | transmittance of a liquid, and an organic reaction can be efficiently advanced in a short time and a high reaction rate.

JP 2002-346392 A Japanese Patent No. 5268722

  Since the above esterification reaction is an equilibrium reaction, as a method of bringing the equilibrium closer to the ester production side, using a large amount of alcohol by using alcohol as a solvent, the equilibrium is brought closer to the production side. Can be considered.

  Here, if the alcohol used for the production of the ester compound is an inexpensive raw material such as methanol, even if it is used in a large amount, no major problem will occur with respect to the production price of the ester compound. However, when the alcohol residue portion of the ester compound for production has a special structure, a special alcohol is used as a raw material. Since such an alcohol is expensive, the ester is used in a large amount. The problem is that the production price of the compound is high.

  Therefore, when such an expensive alcohol is used as a raw material, since the monolithic organic porous cation exchanger is porous, the alcohol is absorbed inside the porous body, and other than being used for the reaction. Since a large excess of alcohol is required, it is necessary to carry out the esterification reaction in a solvent.

  However, as a result of investigations by the present inventors, an esterification reaction between a carboxylic acid and a small excess of alcohol was carried out in an inert solvent using a monolithic organic porous cation exchanger as a catalyst. It turns out that the rate does not increase above a certain level.

  Therefore, the object of the present invention is to increase the esterification rate when the monolithic organic porous cation exchanger is used as a catalyst and the esterification reaction of carboxylic acid and alcohol is carried out in an inert solvent. It is providing the manufacturing method of an ester compound.

  In such a situation, the present inventors have conducted intensive studies, and as a result, when contacting the monolithic organic porous cation exchanger, carboxylic acid, alcohol and solvent, the carboxylic acid to the monolithic organic porous cation exchanger, The contact order of the alcohol and the solvent is changed to the contact order in which the alcohol does not come into contact with the monolithic organic porous cation exchanger before the solvent comes into contact with the monolithic organic porous cation exchanger. In addition, the present inventors have found that the esterification rate is higher than the case where the alcohol is brought into contact before the solvent is brought into contact, and the present invention has been completed.

That is, the present invention is a method for producing an ester compound by reacting a carboxylic acid and an alcohol in a solvent in the presence of a monolithic organic porous cation exchanger,
When contacting the monolithic organic porous cation exchanger, the carboxylic acid, the alcohol and the solvent, the contact order of the carboxylic acid, the alcohol and the solvent to the monolithic organic porous cation exchanger is as follows: Bringing the alcohol into contact with the monolithic organic porous cation exchanger before the solvent comes into contact;
The present invention provides a method for producing an ester compound.

  According to the present invention, an ester compound capable of increasing the esterification rate when an esterification reaction between a carboxylic acid and an alcohol is carried out in an inert solvent using a monolithic organic porous cation exchanger as a catalyst. The manufacturing method of can be provided.

It is a SEM photograph of the example of a form of the 1st monolithic organic porous cation exchanger. It is a SEM photograph of the example of a form of the 2nd monolithic organic porous cation exchanger. It is a schematic diagram which shows the co-continuous structure of a 2nd monolithic organic porous cation exchanger. It is a SEM photograph of the example of a form of a monolith intermediate (2).

The method for producing an ester compound of the present invention is a method for producing an ester compound by reacting a carboxylic acid and an alcohol in a solvent in the presence of a monolithic organic porous cation exchanger,
When contacting the monolithic organic porous cation exchanger, the carboxylic acid, the alcohol and the solvent, the contact order of the carboxylic acid, the alcohol and the solvent to the monolithic organic porous cation exchanger is as follows: Bringing the alcohol into contact with the monolithic organic porous cation exchanger before the solvent comes into contact;
Is a method for producing an ester compound.

  The method for producing an ester compound of the present invention is a method for producing an ester compound in which a monolithic organic porous cation exchanger is used as an acid catalyst and a carboxylic acid and an alcohol are reacted in a solvent to obtain an ester compound. .

  The carboxylic acid which concerns on the manufacturing method of the ester compound of this invention is not restrict | limited in particular, A saturated carboxylic acid, unsaturated carboxylic acid, aromatic carboxylic acid, a hydroxy acid, etc. are mentioned. In addition, the carboxylic acid according to the method for producing an ester compound of the present invention may be one in which a part of the molecule is substituted with a halogen, a cyano group, an alkoxy group, a phenyl group or the like. The carboxylic acid according to the method for producing an ester compound of the present invention may be any of monovalent carboxylic acid, divalent carboxylic acid, and trivalent or higher polyvalent carboxylic acid. The carboxylic acid which concerns on the manufacturing method of the ester compound of this invention may be 1 type of these individually, or may be a combination of 2 or more types. Examples of the carboxylic acid according to the method for producing the ester compound of the present invention include formic acid, acetic acid, propionic acid, butyric acid, valeric acid, caproic acid, enanthic acid, caprylic acid, octanoic acid, decanoic acid, myristic acid, palmitic acid, Stearic acid, acrylic acid, methacrylic acid, oxalic acid, malonic acid, succinic acid, benzoic acid, phthalic acid, 4-cyanobenzoic acid, 4-ethoxybenzoic acid, 4-t-butylbenzoic acid, 4-phenylbenzoic acid, Cinnamic acid, dihydrocinnamic acid, phenylpropionic acid, 6-phenylhexanoic acid, diphenylacetic acid, lactic acid, malic acid, tartaric acid and the like can be mentioned.

  It does not restrict | limit especially as alcohol which concerns on the manufacturing method of the ester compound of this invention, A saturated alcohol, unsaturated alcohol, aromatic alcohol, etc. are mentioned. In addition, the alcohol according to the method for producing an ester compound of the present invention may be one in which a part of the molecule is substituted with a halogen, a cyano group, a methoxy group or the like. Moreover, the alcohol which concerns on the manufacturing method of the ester compound of this invention may be any of monohydric alcohol, divalent alcohol, and trihydric or higher polyhydric alcohol. The alcohol according to the method for producing an ester compound of the present invention may be one of these alone or a combination of two or more. As alcohol which concerns on the manufacturing method of the ester compound of this invention, methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, 2-butanol, t-butanol, pentanol, hexanol, heptanol, octanol, 2 -Ethylhexanol, nonanol, decanol, undecyl alcohol, lauryl alcohol, allyl alcohol, 2-phenylethanol, 3-phenyl-1-propanol and the like.

  The solvent relating to the ester compound production method of the present invention is an inert solvent for the esterification reaction, that is, an inert solvent for the monolithic organic porous cation exchanger that is a carboxylic acid, an alcohol, and an acid catalyst. is there. And as a solvent which concerns on the manufacturing method of the ester compound of this invention, if it is a solvent inactive in esterification reaction, it will not restrict | limit in particular, For example, saturated hydrocarbons, such as hexane, heptane, a cyclohexane, benzene, toluene, Aromatic hydrocarbons such as xylene and ethylbenzene, chain or cyclic saturated ethers such as diethyl ether, tetrahydrofuran and dioxane, acetonitrile, dichloromethane, dichloroethane and the like can be mentioned. Of these, toluene, hexane, and heptane are preferred as the solvent for the ester compound production method of the present invention. The solvent which concerns on the manufacturing method of the ester compound of this invention may be single 1 type of these, or 2 or more types of combinations may be sufficient as it.

  The monolithic organic porous cation exchanger according to the method for producing an ester compound of the present invention is a porous body in which a cation exchange group is introduced into the monolithic organic porous body. The monolithic organic porous body according to the monolithic organic porous cation exchanger is a porous body having a skeleton formed of an organic polymer and a large number of communication holes serving as a flow path for a reaction solution between the skeletons. The monolithic organic porous cation exchanger is a porous body introduced so that cation exchange groups are uniformly distributed in the skeleton of the monolithic organic porous body. In the present specification, the “monolithic organic porous body” is also simply referred to as “monolith”, and the “monolithic organic porous cation exchanger” is also simply referred to as “monolith cation exchanger”. The “monolithic organic porous intermediate (2)” that is an intermediate in the production (precursor of the second monolith) is also simply referred to as “monolith intermediate (2)”.

  The monolith cation exchanger according to the method for producing an ester compound of the present invention is obtained by introducing a cation exchange group into a monolith, and its structure is an organic porous body composed of a continuous skeleton phase and a continuous pore phase. The thickness of the continuous skeleton is 1 to 100 μm, the average diameter of the continuous pores is 1 to 1000 μm, and the total pore volume is 0.5 to 50 mL / g.

  The thickness of the continuous skeleton in the dry state of the monolith cation exchanger is 1 to 100 μm. When the thickness of the continuous skeleton of the monolith cation exchanger is less than 1 μm, the cation exchange capacity per volume is reduced, and the mechanical strength is lowered. Since the exchanger is greatly deformed, it is not preferable. Furthermore, the contact efficiency between the reaction solution and the monolith cation exchanger decreases, and the catalytic activity decreases, which is not preferable. On the other hand, if the thickness of the continuous skeleton of the monolith cation exchanger exceeds 100 μm, the skeleton becomes too thick, and it takes time to diffuse the substrate, which is not preferable. The thickness of the continuous skeleton is determined by SEM observation.

  The average diameter of the continuous pores in the dry state of the monolith cation exchanger is 1-1000 μm. When the average diameter of the continuous pores of the monolith cation exchanger is less than 1 μm, the diffusibility of the substrate and the solvent into the monolith cation exchanger is not preferable. On the other hand, if the average diameter of the continuous pores of the monolith cation exchanger exceeds 1000 μm, the contact between the reaction solution and the monolith cation exchanger becomes insufficient, and the catalytic activity decreases, which is not preferable. In addition, the average diameter of the continuous void | hole in the dry state of a monolith cation exchanger is measured by the mercury intrusion method, and refers to the maximum value of the pore distribution curve obtained by the mercury intrusion method.

  The total pore volume in the dry state of the monolith cation exchanger is 0.5 to 50 mL / g. If the total pore volume of the monolith cation exchanger is less than 0.5 mL / g, it is not preferable because the contact efficiency of the substrate and the solvent becomes low. Further, the permeate volume per unit cross-sectional area becomes small, and the throughput is low. Is unfavorable because it decreases. On the other hand, if the total pore volume of the monolith cation exchanger exceeds 50 mL / g, the cation exchange capacity per volume is lowered and the catalytic activity is lowered, which is not preferable. Further, the mechanical strength is lowered, and the monolith cation exchanger is greatly deformed particularly when the liquid is passed at a high speed, and the pressure loss at the time of the liquid passing increases rapidly. The total pore volume is measured by a mercury intrusion method.

  Examples of the structure of such a monolith cation exchanger are disclosed in Japanese Unexamined Patent Application Publication Nos. 2002-306976 and 2009-62512, and Japanese Unexamined Patent Application Publication No. 2009-67982. Examples thereof include a co-continuous structure, a particle aggregation structure disclosed in JP2009-7550A, and a particle composite structure disclosed in JP2009-108294A.

  The monolith cation exchanger has a cation exchange capacity per weight in the dry state of 1 to 6 mg equivalent / g. When the cation exchange capacity in the dry state of the monolith cation exchanger is less than 1 mg equivalent / g, it is not preferable because the catalytic activity is low and the catalyst activity is low, whereas when it exceeds 6 mg equivalent / g, the cation exchange group introduction reaction Is a harsh condition, and the oxidation deterioration of the monolith is remarkably advanced. The cation exchange capacity of the porous body in which the cation exchange group is introduced only on the skeleton surface cannot be determined in general depending on the kind of the porous body or the cation exchange group, but is at most 500 μg equivalent / g.

  In the monolith cation exchanger, the introduced cation exchange groups are uniformly distributed not only on the surface of the monolith but also inside the skeleton of the monolith. Here, “the cation exchange groups are uniformly distributed” means that the distribution of the cation exchange groups is uniformly distributed on the surface and inside the skeleton in the order of at least μm. The distribution state of the cation exchange group can be easily confirmed by using EPMA. In addition, if the cation exchange groups are uniformly distributed not only on the surface of the monolith but also within the skeleton of the monolith, the physical and chemical properties of the surface and the interior can be made uniform, so that they are resistant to swelling and shrinkage. Improves.

  Examples of the cation exchange group introduced into the monolith cation exchanger include a sulfonic acid group, a carboxyl group, an iminodiacetic acid group, a phosphoric acid group, and a phosphoric acid ester group.

  In the monolith cation exchanger, the material constituting the continuous skeleton is an organic polymer material having a crosslinked structure. The crosslink density of the polymer material is not particularly limited, but it contains 0.1 to 30 mol%, preferably 0.1 to 20 mol% of crosslinkable structural units with respect to all structural units constituting the polymer material. Is preferred. If the cross-linking structural unit is less than 0.1 mol%, the mechanical strength is insufficient, which is not preferable. On the other hand, if it exceeds 30 mol%, it may be difficult to introduce a cation exchange group, which is not preferable. The type of the polymer material is not particularly limited, and examples thereof include aromatic vinyl polymers such as polystyrene, poly (α-methylstyrene), polyvinyl toluene, polyvinyl benzyl chloride, polyvinyl biphenyl, and polyvinyl naphthalene; polyolefins such as polyethylene and polypropylene; Poly (halogenated polyolefin) such as vinyl chloride and polytetrafluoroethylene; Nitrile-based polymer such as polyacrylonitrile; Cross-linking weight of (meth) acrylic polymer such as polymethyl methacrylate, polyglycidyl methacrylate, and polyethyl acrylate Coalescence is mentioned. The polymer may be a polymer obtained by copolymerizing a single vinyl monomer and a crosslinking agent, a polymer obtained by polymerizing a plurality of vinyl monomers and a crosslinking agent, or a blend of two or more types of polymers. It may be what was done. Among these organic polymer materials, a cross-linked polymer of an aromatic vinyl polymer because of the ease of forming a continuous structure, the ease of introducing a cation exchange group and the high mechanical strength, and the high stability to acids or alkalis. In particular, styrene-divinylbenzene copolymer and vinylbenzyl chloride-divinylbenzene copolymer are preferable materials.

<Form example of monolithic organic porous cation exchanger>
Examples of the form of the monolith cation exchanger include the following first monolith cation exchanger and second monolith cation exchanger. Examples of monoliths into which cation exchange groups are introduced include the following first monolith and second monolith.

<Description of the first monolith and the first monolith cation exchanger>
In the method for producing an ester compound of the present invention, the first monolith cation exchanger, which is an acid catalyst, has a common opening (mesopore) having an average diameter of 1 to 1000 μm in the dry state in the wall of the macropore and the macropore connected to each other. The total pore volume in the dry state is 1 to 50 mL / g, has cation exchange groups, the cation exchange groups are uniformly distributed, and the weight in the dry state A monolith cation exchanger having a cation exchange capacity per unit of 1 to 6 mg equivalent / g. The first monolith is a monolith before the cation exchange group is introduced, and has a common pore (mesopore) having an average diameter of 1 to 1000 μm in a dry state in the macropores and the macropore walls connected to each other. It is an organic porous body having an open cell structure and a total pore volume in a dry state of 1 to 50 mL / g.

  In the first monolith cation exchanger, bubble-shaped macropores overlap each other, and the overlapping portion is in a dry state with a common opening (mesopore) having an average diameter of 1 to 1000 μm, preferably 10 to 200 μm, particularly preferably 20 to 100 μm. A continuous macropore structure, most of which has an open pore structure. In the open pore structure, when a liquid is flowed, the inside of bubbles formed by the macropores and the mesopores becomes a flow path. The number of overlapping macropores is 1 to 12 for one macropore, and 3 to 10 for many. FIG. 1 shows a scanning electron microscope (SEM) photograph of an embodiment of the first monolith cation exchanger. The first monolith cation exchanger shown in FIG. 1 has a large number of cellular macropores. The cell-shaped macropores overlap each other, and the overlapping portion is a continuous macropore structure having a common opening (mesopore), most of which has an open pore structure. When the average diameter in the dry state of the mesopore is less than 1 μm, it is not preferable because the diffusibility of the substrate and the solvent into the monolith cation exchanger is reduced, and when the average diameter in the dry state of the mesopore exceeds 1000 μm, the reaction Since the contact between the liquid and the monolith cation exchanger becomes insufficient and the catalytic activity is lowered, it is not preferable. Since the structure of the first monolith cation exchanger is an open cell structure as described above, the macropore group and the mesopore group can be uniformly formed, and the particle aggregation as described in JP-A-8-252579 is also possible. The pore volume and specific surface area can be remarkably increased compared to the type porous body.

  In the present invention, the average diameter of the opening of the first monolith in the dry state and the average diameter of the opening of the first monolith cation exchanger in the dry state are measured by the mercury intrusion method, and are obtained by the mercury intrusion method. The maximum value of the pore distribution curve.

  The total pore volume per weight in the dry state of the first monolith cation exchanger is 1 to 50 mL / g, preferably 2 to 30 mL / g. When the total pore volume is less than 1 mL / g, the contact efficiency of the substrate and the solvent is lowered, which is not preferable. Further, the permeation amount per unit cross-sectional area is reduced, and the processing ability is lowered. On the other hand, if the total pore volume exceeds 50 mL / g, the mechanical strength is lowered, and the monolith cation exchanger is greatly deformed particularly when the liquid is passed at a high flow rate. Furthermore, since the contact efficiency between the reaction solution and the monolith cation exchanger is lowered, the catalytic effect is also lowered, which is not preferable. In the conventional particulate porous cation exchange resin, the total pore volume is 0.1 to 0.9 ml / g at the most. Those having a specific surface area can be used.

  In the first monolith cation exchanger, the material constituting the skeleton is an organic polymer material having a crosslinked structure. Although the crosslinking density of the polymer material is not particularly limited, it contains 0.3 to 10 mol%, preferably 0.3 to 5 mol% of crosslinked structural units with respect to all structural units constituting the polymer material. It is preferable. If the cross-linking structural unit is less than 0.3 mol%, the mechanical strength is insufficient, which is not preferable. On the other hand, if it exceeds 10 mol%, it may be difficult to introduce a cation exchange group, which is not preferable.

  There is no restriction | limiting in particular in the kind of organic polymer material which comprises the frame | skeleton of a 1st monolith cation exchanger, For example, fragrances, such as polystyrene, poly ((alpha) -methylstyrene), polyvinyl toluene, polyvinyl benzyl chloride, polyvinyl biphenyl, polyvinyl naphthalene, etc. Acrylic vinyl polymers; Polyolefins such as polyethylene and polypropylene; Poly (halogenated polyolefins) such as polyvinyl chloride and polytetrafluoroethylene; Nitrile polymers such as polyacrylonitrile; Polymethyl methacrylate, Polyglycidyl methacrylate, Polyethyl acrylate And a crosslinked polymer such as a (meth) acrylic polymer. The organic polymer may be a polymer obtained by copolymerizing a single vinyl monomer and a crosslinking agent, a polymer obtained by polymerizing a plurality of vinyl monomers and a crosslinking agent, or two or more kinds of polymers. It may be blended. Among these organic polymer materials, the cross-linking weight of the aromatic vinyl polymer is determined by the ease of forming a continuous macropore structure, the ease of introducing a cation exchange group and the high mechanical strength, and the high stability to acids or alkalis. A styrene-divinylbenzene copolymer and a vinylbenzyl chloride-divinylbenzene copolymer are particularly preferable materials.

  Examples of the cation exchange group introduced into the first monolith cation exchanger include a carboxylic acid group, an iminodiacetic acid group, a sulfonic acid group, a phosphoric acid group, and a phosphoric ester group. The cation exchange group introduced into the first monolith cation exchanger is the same as in the second monolith cation.

  In the first monolith cation exchanger (the same applies to the second monolith cation exchanger), the introduced cation exchange groups are uniformly distributed not only on the surface of the porous body but also within the skeleton of the porous body. doing. Here, “the cation exchange groups are uniformly distributed” means that the distribution of the cation exchange groups is uniformly distributed on the surface and inside the skeleton in the order of at least μm. The distribution state of the cation exchange group is confirmed by using EPMA. In addition, if the cation exchange group is uniformly distributed not only on the surface of the monolith but also within the skeleton of the porous body, the physical and chemical properties of the surface and the interior can be made uniform, so that the swelling and shrinkage can be achieved. The durability against is improved.

  The cation exchange capacity per weight in the dry state of the first monolith cation exchanger is 1 to 6 mg equivalent / g. When the cation exchange capacity per weight in the dry state is in the above range, the environment around the catalyst active point such as the pH inside the catalyst can be changed, thereby increasing the catalyst activity. The cation exchange capacity of the porous body in which the cation exchange group is introduced only on the surface cannot be determined unconditionally depending on the kind of the porous body or the cation exchange group, but is at most 500 μg equivalent / g.

<Method for producing first monolith and first monolith cation exchanger>
Although it does not restrict | limit especially as a manufacturing method of a 1st monolith, An example of the manufacturing method according to the method of Unexamined-Japanese-Patent No. 2002-306976 is shown below. That is, the first monolith is prepared by mixing an oil-soluble monomer not containing a cation exchange group, a surfactant, water and, if necessary, a polymerization initiator to obtain a water-in-oil emulsion, which is polymerized to obtain a monolith. Is obtained. Such a manufacturing method of the first monolith is preferable in that the porous structure of the monolith can be easily controlled.

  The oil-soluble monomer that does not contain a cation exchange group used in the production of the first monolith contains neither a cation exchange group such as a carboxylic acid group or a sulfonic acid group nor an anion exchange group such as a quaternary ammonium group, This refers to a lipophilic monomer that has a low solubility in water. Specific examples of these monomers include styrene, α-methylstyrene, vinyl toluene, vinyl benzyl chloride, divinyl benzene, ethylene, propylene, isobutene, butadiene, isoprene, chloroprene, vinyl chloride, vinyl bromide, vinylidene chloride, tetrafluoroethylene. , Acrylonitrile, methacrylonitrile, vinyl acetate, methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, trimethylolpropane triacrylate, butanediol diacrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate , Butyl methacrylate, 2-ethylhexyl methacrylate, cyclohexyl methacrylate, benzyl methacrylate, glycidyl methacrylate, ethylene glycol Dimethacrylate and the like. These monomers can be used singly or in combination of two or more. However, in the present invention, a crosslinkable monomer such as divinylbenzene or ethylene glycol dimethacrylate is selected as at least one component of the oil-soluble monomer, and its content is preferably 0.3 to 10 mol% in the total oil-soluble monomer. Is preferably 0.3 to 5 mol% from the viewpoint that a cation exchange group can be quantitatively introduced in a later step and a sufficient mechanical strength can be secured practically.

  The surfactant used in the production of the first monolith is not particularly limited as long as it can form a water-in-oil (W / O) emulsion when an oil-soluble monomer containing no cation exchange group and water are mixed. There is no limitation, such as sorbitan monooleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene nonylphenyl ether, polyoxyethylene stearyl ether, polyoxyethylene sorbitan monooleate Non-cationic surfactants; anionic surfactants such as potassium oleate, sodium dodecylbenzenesulfonate, dioctyl sodium sulfosuccinate; cationic surfactants such as distearyldimethylammonium chloride; lauryldimethylbeta Amphoteric surfactants such emissions may be used. These surfactants can be used singly or in combination of two or more. The water-in-oil emulsion refers to an emulsion in which an oil phase is a continuous phase and water droplets are dispersed therein. The amount of the surfactant added may vary depending on the type of oil-soluble monomer and the size of the target emulsion particles (macropores), but it cannot be generally stated, but the total amount of oil-soluble monomer and surfactant Can be selected within a range of about 2 to 70%. Moreover, although not necessarily essential, in order to control the bubble shape and size of the monolith, alcohols such as methanol and stearyl alcohol; carboxylic acids such as stearic acid; hydrocarbons such as octane, dodecane and toluene; tetrahydrofuran, dioxane and the like Cyclic ether can coexist in the system.

  In the production of the first monolith, when forming the monolith by polymerization, a compound that generates radicals by heat and light irradiation is suitably used as the polymerization initiator used as necessary. The polymerization initiator may be water-soluble or oil-soluble. For example, azobisisobutyronitrile, azobisdimethylvaleronitrile, azobiscyclohexanenitrile, azobiscyclohexanecarbonitrile, benzoyl peroxide, persulfate Examples include potassium, ammonium persulfate, hydrogen peroxide-ferrous chloride, sodium persulfate-sodium acid sulfite, and tetramethylthiuram disulfide. However, in some cases, there is a system in which the polymerization proceeds only by heating or light irradiation without adding a polymerization initiator, and in such a system, the addition of the polymerization initiator is unnecessary.

  In the production of the first monolith, the mixing method for mixing the oil-soluble monomer not containing a cation exchange group, a surfactant, water and a polymerization initiator to form a water-in-oil emulsion is not particularly limited. Without mixing each component at once, oil-soluble monomer, surfactant and oil-soluble polymerization initiator oil-soluble component and water or water-soluble polymerization initiator water-soluble component separately After uniformly dissolving, a method of mixing each component can be used. There is no particular limitation on the mixing apparatus for forming the emulsion, and ordinary mixers, homogenizers, high-pressure homogenizers, and objects to be treated are placed in a mixing container, and the mixing container is tilted and revolved around the revolution axis. While rotating, a so-called planetary stirring device that stirs and mixes the object to be processed can be used, and an appropriate device may be selected to obtain the desired emulsion particle size. Moreover, there is no restriction | limiting in particular about mixing conditions, The stirring rotation speed and stirring time which can obtain the target emulsion particle size can be set arbitrarily. Among these mixing apparatuses, the planetary stirring apparatus is preferably used because it can uniformly generate water droplets in the W / O emulsion and can arbitrarily set the average diameter within a wide range.

  In the production of the first monolith, various polymerization conditions for polymerizing the water-in-oil emulsion thus obtained can be selected depending on the type of monomer and the initiator system. For example, when azobisisobutyronitrile, benzoyl peroxide, potassium persulfate, or the like is used as a polymerization initiator, it can be heated and polymerized at 30 to 100 ° C. for 1 to 48 hours in a sealed container under an inert atmosphere. When hydrogen peroxide-ferrous chloride, sodium persulfate-sodium acid sulfite, etc. are used as initiators, polymerization can be carried out at 0-30 ° C. for 1-48 hours in a sealed container under an inert atmosphere. That's fine. After completion of the polymerization, the content is taken out and subjected to Soxhlet extraction with a solvent such as isopropanol to remove the unreacted monomer and the remaining surfactant to obtain a first monolith.

  The method for producing the first monolith cation exchanger is not particularly limited, and in the first monolith production method, instead of the monomer not containing a cation exchange group, a monomer containing a cation exchange group, for example, the above cation A method of polymerizing an oil-soluble monomer that does not contain an exchange group using a monomer into which a cation exchange group such as a carboxylic acid group or a sulfonic acid group has been introduced to form a monolith cation exchanger in one step, including a cation exchange group For example, a method in which a monomer is polymerized to form a first monolith and then a cation exchange group is introduced. Among these methods, the method of forming a first monolith by polymerization using a monomer that does not contain a cation exchange group and then introducing the cation exchange group makes it easy to control the porous structure of the monolith cation exchanger. Quantitative introduction of a cation exchange group is also possible, which is preferable.

  The method for introducing a cation exchange group into the first monolith is not particularly limited, and a known method such as a polymer reaction or graft polymerization can be used. For example, as a method of introducing a sulfonic acid group, if the monolith is a styrene-divinylbenzene copolymer or the like, a method of sulfonation using chlorosulfuric acid, concentrated sulfuric acid or fuming sulfuric acid; A method of grafting a sodium styrenesulfonate or acrylamido-2-methylpropanesulfonic acid by introducing a mobile group into the skeleton surface or inside the skeleton; Similarly, after graft polymerization of glycidyl methacrylate, a sulfonic acid group is introduced by functional group conversion. And the like. Among these methods, a method of introducing sulfonic acid into a styrene-divinylbenzene copolymer using chlorosulfuric acid is preferable because cation exchange groups can be introduced uniformly and quantitatively. Examples of the cation exchange group to be introduced include cation exchange groups such as a carboxylic acid group, an iminodiacetic acid group, a sulfonic acid group, a phosphoric acid group, and a phosphoric acid ester group.

<Description of Second Monolith and Second Monolith Cation Exchanger>
In the method for producing an ester compound of the present invention, the second monolith cation exchanger, which is an acid catalyst, is an average composed of an aromatic vinyl polymer containing 0.1 to 5.0 mol% of a crosslinked structural unit among all the structural units. A co-continuous structure comprising a three-dimensionally continuous skeleton having a thickness of 1 to 60 μm in a dry state and three-dimensionally continuous pores having an average diameter of 10 to 200 μm in a dry state between the skeletons. The total pore volume in the dry state is 0.5 to 10 mL / g, has a cation exchange group, and the cation exchange capacity per weight in the dry state is 1 to 6 mg equivalent / g, It is a monolith cation exchanger in which cation exchange groups are uniformly distributed in the organic porous cation exchanger. Further, the second monolith is a monolith before the cation exchange group is introduced, and the average thickness of the aromatic monolithic polymer containing 0.1 to 5.0 mol% of the crosslinked structural unit in all the structural units. Is a co-continuous structure comprising a three-dimensionally continuous skeleton of 1 to 60 μm in a dry state and three-dimensionally continuous pores having an average diameter of 10 to 200 μm between the skeletons, It is an organic porous material having a total pore volume of 0.5 to 10 mL / g in a dry state.

  The second monolith cation exchanger has a three-dimensional continuous skeleton having an average thickness of 1 to 60 μm, preferably 3 to 58 μm in a dry state, and an average diameter between the skeletons of 10 to 200 μm in a dry state, preferably Is a co-continuous structure composed of three-dimensionally continuous pores of 15 to 180 μm, particularly preferably 20 to 150 μm. FIG. 2 shows an SEM photograph of an embodiment of the second monolith cation exchanger, and FIG. 3 shows a schematic diagram of a co-continuous structure of the second monolith cation exchanger. As shown in the schematic diagram of FIG. 3, the co-continuous structure is a structure 10 in which a continuous skeleton phase 1 and a continuous pore phase 2 are intertwined and each of them is three-dimensionally continuous. The continuous pores 2 have higher continuity of the pores than the conventional open-cell type monolith and the particle aggregation type monolith, and the size thereof is not biased. Moreover, since the skeleton is thick, the mechanical strength is high.

  If the average diameter of the three-dimensionally continuous pores is less than 10 μm in the dry state, it is not preferable because the substrate and the solvent are difficult to diffuse, and if it exceeds 200 μm, contact between the reaction solution and the monolith cation exchanger is not good. As a result, the catalytic activity becomes insufficient, which is not preferable. Further, if the average thickness of the skeleton is less than 1 μm in the dry state, the ion exchange capacity is lowered, and the mechanical strength is lowered, which is not preferable. Furthermore, the contact efficiency between the reaction solution and the monolith cation exchanger is lowered, and the catalytic effect is lowered. On the other hand, if the thickness of the skeleton exceeds 60 μm, the skeleton becomes too thick and the diffusion of the solvent and the substrate becomes non-uniform, which is not preferable.

  The average diameter of the dried second monolith opening, the average diameter of the dried second monolith cation exchanger opening, and the dried second monolith obtained in Step I of the production of the second monolith described below. The average diameter of the opening of the monolith intermediate (2) is obtained by the mercury intrusion method, and indicates the maximum value of the pore distribution curve obtained by the mercury intrusion method. The average thickness of the skeleton of the second monolith cation exchanger in the dry state can be determined by SEM observation of the second monolith cation exchanger in the dry state. Specifically, SEM observation of the second monolith cation exchanger in the dry state is performed at least three times, the thickness of the skeleton in the obtained image is measured, and the average value thereof is taken as the average thickness. The skeleton has a rod-like shape and a circular cross-sectional shape, but may have a cross-section with a different diameter such as an elliptical cross-sectional shape. The thickness in this case is the average of the minor axis and the major axis.

  The total pore volume per weight in the dry state of the second monolith cation exchanger is 0.5 to 10 mL / g. If the total pore volume is less than 0.5 mL / g, it is not preferable because the contact efficiency of the substrate and the solvent is low, and further, the permeation amount per unit cross-sectional area becomes small, and the processing amount decreases. Absent. On the other hand, if the total pore volume exceeds 10 ml / g, the contact efficiency between the reaction solution and the monolith cation exchanger is lowered, and the catalyst efficiency is also lowered. If the size of the three-dimensionally continuous pores and the total pore volume are in the above ranges, the contact with the reaction solution is extremely uniform and the contact area becomes large.

  In the second monolith cation exchanger, the material constituting the skeleton is an aromatic containing 0.1 to 5 mol%, preferably 0.5 to 3.0 mol% of a crosslinked structural unit in all the structural units. It is a vinyl polymer and is hydrophobic. If the cross-linking structural unit is less than 0.1 mol%, the mechanical strength is insufficient, which is not preferable. On the other hand, if it exceeds 5 mol%, the structure of the porous body tends to deviate from the bicontinuous structure. There is no restriction | limiting in particular in the kind of aromatic vinyl polymer, For example, a polystyrene, poly ((alpha) -methylstyrene), polyvinyl toluene, polyvinyl benzyl chloride, polyvinyl biphenyl, polyvinyl naphthalene etc. are mentioned. The polymer may be a polymer obtained by copolymerizing a single vinyl monomer and a crosslinking agent, a polymer obtained by polymerizing a plurality of vinyl monomers and a crosslinking agent, or a blend of two or more types of polymers. It may be what was done. Among these organic polymer materials, a styrene-divinylbenzene copolymer is used because of its ease of forming a co-continuous structure, ease of introduction of a cation exchange group, high mechanical strength, and high stability to acids or alkalis. And vinylbenzyl chloride-divinylbenzene copolymer is preferred.

  The cation exchange group introduced into the second monolith cation exchanger is the same as the cation exchange group introduced into the first monolith cation exchanger.

  In the second monolith cation exchanger, the introduced cation exchange groups are uniformly distributed not only on the surface of the porous body but also within the skeleton of the porous body.

  The second monolith cation exchanger has a cation exchange capacity of 1 to 6 mg equivalent / g cation exchange capacity per weight in the dry state. Since the second monolith cation exchanger has high continuity and uniformity of three-dimensionally continuous pores, the substrate and the solvent are uniformly diffused. Therefore, the reaction proceeds quickly. When the cation exchange capacity per weight is in the above range, the environment around the catalytic activity point such as the pH inside the catalyst can be changed, and thereby the catalytic activity is increased.

<Method for producing second monolith and second monolith inion exchanger>
The second monolith prepares a water-in-oil emulsion by stirring a mixture of oil-soluble monomer, surfactant and water that does not contain a cation exchange group, and then polymerizes the water-in-oil emulsion to give a total pore size. Step I for obtaining a monolithic organic porous intermediate (hereinafter also referred to as monolith intermediate (2)) having a continuous macropore structure having a volume of more than 16 mL / g and 30 mL / g or less, an aromatic vinyl monomer, one In all oil-soluble monomers having at least two vinyl groups in the molecule, 0.3 to 5 mol% of the crosslinking agent, aromatic vinyl monomer and crosslinking agent are dissolved, but the aromatic vinyl monomer is polymerized to form. Preparation of a mixture comprising an organic solvent in which the polymer does not dissolve and a polymerization initiator, Step II, Monolith intermediate obtained in Step I while leaving the mixture obtained in Step II standing Polymerization was conducted in the presence of 2), III to obtain a second monolith is an organic porous material is a co-continuous structure, obtained by performing.

  In the step I relating to the second monolith production method, the step I for obtaining the monolith intermediate (2) may be performed in accordance with the method described in JP-A-2002-306976.

  That is, in step I according to the second monolith production method, examples of the oil-soluble monomer that does not include a cation exchange group include cation exchange such as carboxylic acid group, sulfonic acid group, tertiary amino group, and quaternary ammonium group. Examples thereof include a lipophilic monomer which does not contain a group and has low solubility in water. Specific examples of these monomers include aromatic vinyl monomers such as styrene, α-methylstyrene, vinyl toluene, vinyl benzyl chloride, vinyl biphenyl and vinyl naphthalene; α-olefins such as ethylene, propylene, 1-butene and isobutene; butadiene Diene monomers such as vinyl chloride, vinyl bromide, vinylidene chloride and tetrafluoroethylene; nitrile monomers such as acrylonitrile and methacrylonitrile; vinyl esters such as vinyl acetate and vinyl propionate Methyl acrylate, ethyl acrylate, butyl acrylate, 2-ethylhexyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, butyl methacrylate, 2-ethyl methacrylate Sill, cyclohexyl methacrylate, benzyl methacrylate, and (meth) acrylic monomer of glycidyl methacrylate. Among these monomers, preferred are aromatic vinyl monomers such as styrene, α-methylstyrene, vinyl toluene, vinyl benzyl chloride, divinyl benzene and the like. These monomers can be used singly or in combination of two or more. However, a crosslinkable monomer such as divinylbenzene or ethylene glycol dimethacrylate is selected as at least one component of the oil-soluble monomer, and its content is 0.3 to 5 mol%, preferably 0.3 to the total oil-soluble monomer. 3 mol% is preferable because it is advantageous for forming a co-continuous structure.

  The surfactant used in Step I according to the second monolith production method can form a water-in-oil (W / O) emulsion when an oil-soluble monomer containing no cation exchange group and water are mixed. If it is a thing, there will be no restriction in particular, sorbitan monooleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan trioleate, polyoxyethylene nonyl phenyl ether, polyoxyethylene stearyl ether, polyoxyethylene sorbitan Non-cationic surfactants such as monooleate; anionic surfactants such as potassium oleate, sodium dodecylbenzenesulfonate, dioctyl sodium sulfosuccinate; cationic surfactants such as distearyldimethylammonium chloride; Lau It can be used an amphoteric surfactant such as Le dimethyl betaine. These surfactants can be used singly or in combination of two or more. The water-in-oil emulsion refers to an emulsion in which an oil phase is a continuous phase and water droplets are dispersed therein. The amount of the surfactant added may vary depending on the type of oil-soluble monomer and the size of the target emulsion particles (macropores), but it cannot be generally stated, but the total amount of oil-soluble monomer and surfactant Can be selected within a range of about 2 to 70%.

  Further, in the step I according to the second monolith production method, a polymerization initiator may be used as necessary when forming the water-in-oil emulsion. As the polymerization initiator, a compound that generates radicals by heat or light irradiation is preferably used. The polymerization initiator may be water-soluble or oil-soluble. For example, 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2 , 2′-azobis (2-methylbutyronitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate, 4,4′-azobis ( 4-cyanovaleric acid), 1,1'-azobis (cyclohexane-1-carbonitrile), benzoyl peroxide, lauroyl peroxide, potassium persulfate, ammonium persulfate, tetramethylthiuram disulfide, hydrogen peroxide-ferrous chloride Sodium persulfate-sodium acid sodium sulfite and the like.

  As the mixing method when forming the water-in-oil emulsion by mixing an oil-soluble monomer not containing a cation exchange group, a surfactant, water and a polymerization initiator in Step I according to the second monolith production method. There is no particular limitation, a method of mixing each component at once, an oil-soluble monomer, a surfactant, an oil-soluble component that is an oil-soluble polymerization initiator, and water or a water-soluble polymerization initiator that is water-soluble For example, a method of mixing each component separately after uniformly dissolving the components can be used. There is no particular limitation on the mixing apparatus for forming the emulsion, and a normal mixer, homogenizer, high-pressure homogenizer, or the like can be used, and an appropriate apparatus may be selected to obtain the desired emulsion particle size. Moreover, there is no restriction | limiting in particular about mixing conditions, The stirring rotation speed and stirring time which can obtain the target emulsion particle size can be set arbitrarily.

  The monolith intermediate (2) obtained in step I according to the second method for producing a monolith is an organic polymer material having a crosslinked structure, preferably an aromatic vinyl polymer. Although the crosslinking density of the polymer material is not particularly limited, it contains 0.1 to 5 mol%, preferably 0.3 to 3 mol% of crosslinked structural units with respect to all the structural units constituting the polymer material. Is preferred. When the cross-linking structural unit is less than 0.3 mol%, the mechanical strength is insufficient, which is not preferable. On the other hand, if it exceeds 5 mol%, the structure of the monolith tends to deviate from the co-continuous structure, which is not preferable. In particular, when the total pore volume is 16 to 20 ml / g, the cross-linking structural unit is preferably less than 3 mol% in order to form a co-continuous structure.

  In the step I relating to the second monolith production method, examples of the polymer material of the monolith intermediate (2) include the same as the polymer material of the first monolith.

  The total pore volume per weight in the dry state of the monolith intermediate (2) obtained in Step I according to the second monolith production method is more than 16 mL / g and not more than 30 mL / g, preferably 16 mL / g. More than g and 25 mL / g or less. That is, this monolith intermediate (2) is basically a continuous macropore structure, but the opening (mesopore) that is the overlapping portion of the macropore and the macropore is remarkably large, so that the skeleton constituting the monolith structure is two-dimensional. It has a structure that is almost as close as possible to a one-dimensional rod-like skeleton from the wall surface. FIG. 4 shows an SEM photograph of a form example of the monolith intermediate (2), which has a skeleton close to a rod shape. When this coexists in the polymerization system, a porous body having a co-continuous structure is formed using the structure of the monolith intermediate (2) as a mold. If the total pore volume is too small, the structure of the monolith obtained after polymerizing the vinyl monomer is not preferable because it changes from a co-continuous structure to a continuous macropore structure. On the other hand, if the total pore volume is too large, When the mechanical strength of the monolith obtained after polymerizing the vinyl monomer is lowered or a cation exchange group is introduced, the cation exchange capacity per volume is lowered, which is not preferable. In order to set the total pore volume of the monolith intermediate (2) within the above range, the ratio of monomer to water may be about 1:20 to 1:40.

  In addition, in the monolith intermediate (2) obtained in the step I according to the second method for producing a monolith, the average diameter of openings (mesopores), which is an overlapping portion of macropores and macropores, is 5 to 100 μm in a dry state. When the average diameter of the openings is less than 5 μm in the dry state, the opening diameter of the monolith obtained after polymerizing the vinyl monomer is reduced, and the pressure loss during fluid permeation is increased, which is not preferable. On the other hand, if it exceeds 100 μm, the opening diameter of the monolith obtained after polymerizing the vinyl monomer becomes too large, resulting in insufficient contact between the reaction solution and the monolith cation exchanger, resulting in a decrease in catalytic activity. Therefore, it is not preferable. The monolith intermediate (2) preferably has a uniform structure with the same macropore size and opening diameter, but is not limited to this, and the nonuniform macropore larger than the uniform macropore size in the uniform structure. May be scattered.

  Step II according to the second monolith production method includes an aromatic vinyl monomer, a total oil-soluble monomer having at least two vinyl groups in one molecule, 0.3 to 5 mol% of a crosslinking agent, an aromatic This is a step of preparing a mixture of an organic solvent and a polymerization initiator that dissolves the vinyl monomer and the crosslinking agent but does not dissolve the polymer formed by polymerization of the aromatic vinyl monomer. In addition, there is no order of I process and II process, II process may be performed after I process, and I process may be performed after II process.

  The aromatic vinyl monomer used in Step II according to the second monolith production method is a lipophilic aromatic vinyl monomer that contains a polymerizable vinyl group in the molecule and has high solubility in an organic solvent. Although there is no particular limitation, it is preferable to select a vinyl monomer that produces the same or similar polymer material as the monolith intermediate (2) to be coexisted in the polymerization system. Specific examples of these vinyl monomers include styrene, α-methylstyrene, vinyl toluene, vinyl benzyl chloride, vinyl biphenyl, vinyl naphthalene and the like. These monomers can be used singly or in combination of two or more. Aromatic vinyl monomers preferably used are styrene, vinyl benzyl chloride and the like.

  The addition amount of the aromatic vinyl monomer used in Step II according to the second monolith production method is 5 to 50 times by weight, preferably 5 to 40 times by weight with respect to the monolith intermediate (2) to be coexisted during the polymerization. It is. If the amount of the aromatic vinyl monomer added is less than 5 times that of the monolith intermediate (2), the rod-like skeleton cannot be made thick, and when a cation exchange group is introduced, the cation per volume after the introduction of the cation exchange group This is not preferable because the exchange capacity becomes small. On the other hand, if the amount of the aromatic vinyl monomer added exceeds 50 times, the diameter of the continuous pores becomes small, and the pressure loss during liquid passage becomes large, which is not preferable.

  As the crosslinking agent used in Step II according to the second monolith production method, a crosslinking agent containing at least two polymerizable vinyl groups in the molecule and having high solubility in an organic solvent is preferably used. Specific examples of the crosslinking agent include divinylbenzene, divinylnaphthalene, divinylbiphenyl, ethylene glycol dimethacrylate, trimethylolpropane triacrylate, butanediol diacrylate, and the like. These crosslinking agents can be used singly or in combination of two or more. Preferred cross-linking agents are aromatic polyvinyl compounds such as divinylbenzene, divinylnaphthalene and divinylbiphenyl because of their high mechanical strength and stability to hydrolysis. The amount of the crosslinking agent used is 0.3 to 5 mol%, particularly 0.3 to 3 mol%, based on the total amount of vinyl monomer and crosslinking agent (total oil-soluble monomer). If the amount of the crosslinking agent used is less than 0.3 mol%, it is not preferable because the mechanical strength of the monolith is insufficient. On the other hand, if it is too much, it is difficult to quantitatively introduce the cation exchange group when introducing a cation exchange group. Since it may become, it is not preferable. In addition, it is preferable to use the said crosslinking agent usage-amount so that it may become substantially equal to the crosslinking density of the monolith intermediate (2) coexisted at the time of vinyl monomer / crosslinking agent polymerization. If the amounts used of both are too large, the crosslink density distribution will be biased in the produced monolith, and when cation exchange groups are introduced, cracks are likely to occur during the cation exchange group introduction reaction.

  The organic solvent used in step II of the second monolith production method is an organic solvent that dissolves the aromatic vinyl monomer and the cross-linking agent but does not dissolve the polymer formed by the polymerization of the aromatic vinyl monomer. It is a poor solvent for a polymer produced by polymerization of an aromatic vinyl monomer. Since organic solvents vary greatly depending on the type of aromatic vinyl monomer, it is difficult to list general specific examples. For example, when the aromatic vinyl monomer is styrene, the organic solvents include methanol, ethanol, and propanol. , Butanol, hexanol, cyclohexanol, octanol, 2-ethylhexanol, decanol, dodecanol, propylene glycol, tetramethylene glycol, and other alcohols; chain chains such as diethyl ether, butyl cellosolve, polyethylene glycol, polypropylene glycol, polytetramethylene glycol ( Poly) ethers; chain saturated hydrocarbons such as hexane, heptane, octane, isooctane, decane, dodecane, etc .; ethyl acetate, isopropyl acetate, cellosolve acetate, propionic acid Examples include esters such as chill. Moreover, even if it is a good solvent of polystyrene like a dioxane, THF, and toluene, when it is used with the said poor solvent and the usage-amount is small, it can be used as an organic solvent. These organic solvents are preferably used so that the concentration of the aromatic vinyl monomer is 30 to 80% by weight. When the amount of the organic solvent deviates from the above range and the aromatic vinyl monomer concentration is less than 30% by weight, the polymerization rate is decreased or the monolith structure after polymerization deviates from the range of the second monolith. Absent. On the other hand, if the concentration of the aromatic vinyl monomer exceeds 80% by weight, the polymerization may run away, which is not preferable.

  As the polymerization initiator used in Step II according to the second monolith production method, a compound that generates radicals by heat or light irradiation is preferably used. The polymerization initiator is preferably oil-soluble. Specific examples of the polymerization initiator include 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), 2,2′-azobis (2-methylbutyro). Nitrile), 2,2′-azobis (4-methoxy-2,4-dimethylvaleronitrile), dimethyl 2,2′-azobisisobutyrate, 4,4′-azobis (4-cyanovaleric acid), 1,1 ′ -Azobis (cyclohexane-1-carbonitrile), benzoyl peroxide, lauroyl peroxide, potassium persulfate, ammonium persulfate, tetramethylthiuram disulfide and the like. The amount of the polymerization initiator used varies greatly depending on the type of monomer, polymerization temperature, etc., but can be used in a range of about 0.01 to 5% with respect to the total amount of vinyl monomer and crosslinking agent.

  In Step III according to the second method for producing a monolith, the mixture obtained in Step II is allowed to stand, and polymerization is carried out in the presence of the monolith intermediate (2) obtained in Step I. This is a step of changing the continuous macropore structure of the body (2) to a co-continuous structure to obtain a second monolith that is a co-continuous structure monolith. The monolith intermediate (2) used in the step III plays an extremely important role in creating the monolith having the novel structure of the present invention. As disclosed in JP-A-7-501140 and the like, when a vinyl monomer and a crosslinking agent are allowed to stand in a specific organic solvent in the absence of the monolith intermediate (2), a particle aggregation type monolith shape is obtained. An organic porous body is obtained. On the other hand, when the monolith intermediate (2) having a specific continuous macropore structure is present in the polymerization system as in the case of the second monolith, the structure of the monolith after the polymerization changes dramatically and the particle aggregation structure disappears. Thus, the second monolith having the above-described co-continuous structure is obtained. The reason for this has not been elucidated in detail, but in the absence of the monolith intermediate (2), the crosslinked polymer produced by polymerization precipitates and precipitates in the form of particles to form a particle aggregate structure. On the other hand, when a porous body (intermediate) having a large total pore volume exists in the polymerization system, the vinyl monomer and the crosslinking agent are adsorbed or distributed from the liquid phase to the skeleton of the porous body, and polymerization is performed in the porous body. It is considered that the second monolith having a co-continuous structure is formed as the skeleton constituting the monolith structure changes from a two-dimensional wall surface to a one-dimensional rod-like skeleton.

  In the second method for producing a monolith, the internal volume of the reaction vessel is not particularly limited as long as the monolith intermediate (2) is of a size that allows the monolith intermediate (2) to be present in the reaction vessel, and the monolith intermediate (2 ) May be any of those in which a gap is formed around the monolith in plan view and those in which the monolith intermediate (2) enters the reaction vessel without any gap. Of these, the thick monolith after polymerization is not pressed from the inner wall of the container and enters the reaction container without any gap, and the monolith is not distorted, and the reaction raw materials are not wasted and efficient. Even when the internal volume of the reaction vessel is large and there are gaps around the monolith after polymerization, the vinyl monomer and the crosslinking agent are adsorbed and distributed on the monolith intermediate (2). A particle aggregate structure is not generated in the gap portion inside.

  In step III according to the second monolith production method, the monolith intermediate (2) is impregnated with the mixture (solution) in the reaction vessel. As described above, the blending ratio of the mixture obtained in Step II and the monolith intermediate (2) is 3 to 50 times by weight, preferably 4 to 4 times by weight with respect to the monolith intermediate (2). It is preferable to blend so as to be 40 times. Thereby, it is possible to obtain a second monolith having a thick skeleton while having an appropriate opening diameter. In the reaction vessel, the vinyl monomer and the crosslinking agent in the mixture are adsorbed and distributed on the skeleton of the monolith intermediate that has been allowed to stand, and polymerization proceeds in the skeleton of the monolith intermediate (2).

  In step III according to the second monolith production method, the monolith intermediate (2) is impregnated with the mixture (solution) in the reaction vessel. As described above, the blending ratio of the mixture obtained in Step II and the monolith intermediate (2) is 5 to 50 times by weight of the aromatic vinyl monomer added to the monolith intermediate (2), preferably It is suitable to mix 5 to 40 times. Thereby, it is possible to obtain a second monolith having a co-continuous structure in which pores of an appropriate size are three-dimensionally continuous and a thick skeleton is three-dimensionally continuous. In the reaction vessel, the aromatic vinyl monomer and the cross-linking agent in the mixture are adsorbed and distributed on the skeleton of the monolith intermediate (2) that is allowed to stand, and polymerization proceeds in the skeleton of the monolith intermediate (2).

  Various conditions are selected for the polymerization conditions in the III step according to the second monolith production method depending on the type of monomer and the type of initiator. For example, when 2,2′-azobis (isobutyronitrile), 2,2′-azobis (2,4-dimethylvaleronitrile), benzoyl peroxide, lauroyl peroxide, potassium persulfate, etc. are used as initiators In a sealed container under an inert atmosphere, heat polymerization may be performed at 30 to 100 ° C. for 1 to 48 hours. By heat polymerization, the vinyl monomer adsorbed and distributed on the skeleton of the monolith intermediate (2) and the crosslinking agent are polymerized in the skeleton to thicken the skeleton. After completion of the polymerization, the contents are taken out and extracted with a solvent such as acetone to obtain a second monolith for the purpose of removing unreacted vinyl monomer and organic solvent.

  The second monolith cation exchanger is obtained by performing an IV step for introducing a cation exchange group into the second monolith obtained in the step III.

  The method for introducing a cation exchange group into the second monolith is the same as the method for introducing a cation exchange group into the first monolith.

  The second monolith and the second monolith cation exchanger have high mechanical strength because they have a bone-thick skeleton even though the three-dimensionally continuous pores are extremely large. Further, since the second monolith cation exchanger has a thick skeleton, the cation exchange capacity per volume in a dry state can be increased, and the reaction solution can be passed for a long time at a low pressure and a large flow rate. .

  The monolithic organic porous cation exchanger according to the method for producing an ester compound of the present invention can contain 70 to 90% of water of its own mass (dry mass) in a water equilibrium state. However, if the monolithic organic porous cation exchanger contains a large amount of water, the esterification reaction is difficult to occur. Therefore, the monolithic organic porous cation exchanger used for the esterification reaction (the monolithic organic cation exchanger before the reaction) The porous cation exchanger is preferable in that the lower the water content, the higher the esterification rate. The water content of the monolithic organic porous cation exchanger used for the esterification reaction is preferably 5% by mass or less, particularly preferably 1% by mass or less, from the viewpoint of increasing the esterification rate. As a method for removing water from the monolithic organic porous cation exchanger, a temperature at which the cation exchange group is not decomposed, for example, a method of heating and drying at 120 ° C. or lower, preferably 60 to 110 ° C., a method of drying under reduced pressure, Immerse the monolithic organic porous cation in an organic solvent such as ether, replace the water in the monolithic organic porous cation exchanger with an organic solvent, and then dry, repeatedly using multiple types of organic solvents And a method of replacing water in the monolithic organic porous cation exchanger with an organic solvent.

  And in the manufacturing method of the ester compound of this invention, when making a monolithic organic porous cation exchanger, carboxylic acid, alcohol, and a solvent contact, carboxylic acid, alcohol, and a solvent to a monolithic organic porous cation exchanger are contacted. The contact order is set so that the alcohol does not contact the monolithic organic porous cation exchanger before the solvent contacts. In the method for producing an ester compound of the present invention, the contact timing of the carboxylic acid to the monolithic organic porous cation exchanger is not particularly limited, and the contact timing of the carboxylic acid to the monolithic organic porous cation exchanger is not limited to the solvent. It may be prior to contact, simultaneous with solvent contact, after solvent contact and prior to alcohol contact, after solvent contact and with alcohol contact. It may be simultaneous or after alcohol contact.

  To contact the monolithic organic porous cation exchanger before the solvent contacts with the alcohol in order of contact, for example, after contacting the monolithic organic porous cation exchanger with the solvent first, Contact order in which alcohol is contacted, or contact order in which solvent and alcohol are simultaneously contacted with monolithic organic porous cation exchanger by contacting a mixture of solvent and alcohol with monolithic organic porous cation exchanger. is there. In these contact orders, the timing of contacting the carboxylic acid with the monolithic organic porous cation exchanger is not particularly limited.

When contacting the monolithic organic porous cation exchanger, carboxylic acid, alcohol and solvent, the order of contact of the carboxylic acid, alcohol and solvent with the monolithic organic porous cation exchanger is changed to the monolithic organic porous cation exchanger. Moreover, the following contact order is mentioned as an example of the contact order in which alcohol does not contact before a solvent contacts. In the following, the order of addition to the reaction vessel is shown in the order of the arrows. The order of addition to the reaction vessel is not limited to the following, and the order of contact of the carboxylic acid, alcohol and solvent with the monolithic organic porous cation exchanger depends on the order of contact of the monolithic organic porous cation exchanger with the solvent. The contact order may be such that alcohol does not contact before contact.
<When adding the monolith cation exchanger to the reaction vessel first>
・ Monolith cation exchanger → carboxylic acid → solvent → alcohol / monolith cation exchanger → solvent → carboxylic acid → alcohol / monolith cation exchanger → solvent → alcohol → carboxylic acid / monolith cation exchanger → mixture of solvent and carboxylic acid → Alcohol / monolith cation exchanger → carboxylic acid → solvent / alcohol mixture / monolith cation exchanger → solvent / alcohol mixture → carboxylic acid / monolith cation exchanger → solvent / alcohol / carboxylic acid mixture <solvent / carvone When first adding the acid mixture to the reaction vessel>
・ Mixed liquid of solvent and carboxylic acid → Monolith cation exchanger → Alcohol <When adding solvent to the reaction vessel first>
・ Solvent → carboxylic acid → monolith cation exchanger → alcohol / solvent → monolith cation exchanger → carboxylic acid → alcohol / solvent → monolith cation exchanger → alcohol → carboxylic acid <When carboxylic acid is first added to reaction vessel>
・ Carboxylic acid → monolith cation exchanger → solvent → alcohol / carboxylic acid → solvent → monolith cation exchanger → alcohol / carboxylic acid → monolith cation exchanger → mixture of solvent and alcohol First, the alcohol is brought into contact with the monolithic organic porous cation exchanger by passing a solvent and then a mixture of carboxylic acid, alcohol and solvent before the solvent comes into contact with the monolithic organic porous cation exchanger. The contact of the carboxylic acid, the alcohol and the solvent to the monolithic organic porous cation exchanger can be performed in the order of contact with no water.

  In the method for producing an ester compound of the present invention, it is the ratio of carboxylic acid to alcohol, but in terms of equivalent of carboxyl group and hydroxyl group, the ratio of carboxyl group and hydroxyl group is equivalent, or the hydroxyl group relative to carboxyl group It is the ratio that the group becomes excessive or the ratio that the carboxyl group becomes excessive with respect to the hydroxyl group. More specifically, the ratio of the carboxylic acid and the alcohol is preferably a mixing ratio in which the equivalent ratio of hydroxyl group to carboxyl group (hydroxyl group equivalent / carboxyl group equivalent) is 0.05 to 20, A mixing ratio of 10 is particularly preferred.

  In the production method of the ester compound of the present invention, the amount of the monolithic organic porous cation exchanger is not particularly limited, but in terms of the equivalent of the carboxyl group of the carboxylic acid and the cation exchange group in the monolithic organic porous cation exchanger. The mixing ratio in which the carboxyl group equivalent ratio (carboxyl group equivalent / cation exchange group equivalent) of the carboxylic acid to the monolithic organic porous cation exchanger is 0.1 to 100 is preferable, and the ratio is 0.5 to 50 Is particularly preferred.

  In the method for producing an ester compound of the present invention, the amount of the solvent used is not particularly limited, but is preferably 3 to 100 times the mass of the monolithic organic porous cation exchanger, and particularly preferably the monolithic organic porous cation exchanger. 5 to 50 times the mass of

  In the method for producing an ester compound of the present invention, the monolithic organic porous cation exchanger is contacted with a carboxylic acid, an alcohol and a solvent, or the monolithic organic porous cation exchanger is first contacted with a solvent. Thereafter, the carboxylic acid and the alcohol are reacted while the carboxylic acid and the alcohol are brought into contact with each other, and an esterification reaction is performed to obtain an ester compound. The reaction temperature during the esterification reaction is not particularly limited, but is preferably 20 to 100 ° C, particularly preferably 50 to 90 ° C. The reaction time for the esterification reaction is appropriately selected depending on the amount of reaction raw materials, reaction temperature, etc., but is preferably 0.1 to 48 hours, particularly preferably 0.5 to 24 hours.

  Thus, an ester compound can be obtained by performing the manufacturing method of the ester compound of this invention.

  The method for producing an ester compound of the present invention is a method for producing an ester compound in which a monolithic organic porous cation exchanger and an alcohol are mixed and esterified before bringing the solvent into contact with the monolithic organic porous cation. In comparison, the esterification rate is increased. In the method for producing an ester compound of the present invention, the solvent is introduced into the skeleton of the monolithic organic porous cation by bringing the solvent into contact with the monolithic organic porous cation first or contacting the solvent simultaneously with the alcohol. By incorporating, when alcohol comes into contact with the monolithic organic porous cation exchanger, the alcohol is taken into the monolithic organic porous cation exchanger to prevent the alcohol used in the esterification reaction from decreasing. Can do. Therefore, in the manufacturing method of the ester compound of this invention, esterification rate becomes high.

  Moreover, after performing the manufacturing method of the ester compound of this invention, alcohol can be further mixed with a reaction system, and esterification reaction can be performed again. The mixing amount of the alcohol at that time is equivalent to the hydroxyl group equivalent of the alcohol further mixed after performing the ester compound manufacturing method of the present invention with respect to the equivalent of the carboxyl group of the carboxylic acid before performing the ester compound manufacturing method of the present invention. The mixing amount in which the ratio (hydroxyl group equivalent / carboxyl group equivalent) is 1 to 20 is preferable, and the mixing amount in which 1 to 10 is particularly preferable. Moreover, the reaction temperature and reaction time of the esterification reaction in that case are the same as the reaction temperature and reaction time of the esterification reaction in the manufacturing method of the ester compound of this invention.

(Example)
Next, the present invention will be specifically described by way of examples, but this is merely an example and does not limit the present invention.

Reference Example 1 Production of first monolith cation exchanger (production of first monolith)
19.24 g of styrene, 1.01 g of divinylbenzene, 2.25 g of sorbitan monooleate (hereinafter abbreviated as SMO) and 0.05 g of 2,2′-azobis (isobutyronitrile) were mixed and dissolved uniformly. Next, the styrene / divinylbenzene / SMO / 2,2′-azobis (isobutyronitrile) mixture was added to 180 g of pure water, and a vacuum stirring defoaming mixer (manufactured by EM Corp.) as a planetary stirring device. Was stirred under reduced pressure to obtain a water-in-oil emulsion. This emulsion was quickly transferred to a reaction vessel and allowed to polymerize at 60 ° C. for 24 hours in a static state after sealing. After completion of the polymerization, the content was taken out, extracted with methanol, and then dried under reduced pressure to produce a monolith having a continuous macropore structure. The internal structure of the first monolith A thus obtained was observed by SEM. As a result, it had an open-cell structure, and the average diameter of the opening (mesopore) where the macropores and macropores were measured was 13.2 μm and the total pore volume was 8.4 mL / g. .

(Production of first monolith cation exchanger)
The first monolith A produced by the above method was put into a column reactor, and a solution consisting of 500 g of chlorosulfonic acid and 4 L of dichloromethane was passed through and reacted at 20 ° C. for 3 hours. After completion of the reaction, methanol was added to the system to deactivate unreacted chlorosulfonic acid, and further washed with methanol to take out the product. Finally, it was washed with pure water to obtain a first monolith cation exchanger A.
The obtained first monolith cation exchanger A had a cation exchange capacity of 4.8 mg equivalent / g in a dry state, and it was confirmed that sulfonic acid groups were introduced quantitatively. The average diameter in the dry state of the three-dimensionally continuous pores of the monolith cation exchanger determined from the measurement by the mercury intrusion method was 13.4 μm, and the total pore volume in the dry state was 8.5 mL / g.
Subsequently, in order to confirm the distribution state of the sulfonic acid group in the first monolith cation exchanger A, the distribution state of sulfur was observed by EPMA. The distribution of sulfur in the cross section of the skeleton is that sulfur is uniformly distributed not only on the skeleton surface of the monolith cation exchanger but also inside the skeleton, and the sulfonic acid groups are uniformly introduced into the monolith cation exchanger. Was confirmed.

Reference Example 2 Production of Second Monolith Cation Exchanger (Production of Monolith Intermediate (2) (Step I))
9.28 g of styrene, 0.19 g of divinylbenzene, 0.50 g of sorbitan monooleate (hereinafter abbreviated as SMO) and 0.25 g of 2,2′-azobis (isobutyronitrile) were mixed and dissolved uniformly. Next, the styrene / divinylbenzene / SMO / 2,2′-azobis (isobutyronitrile) mixture was added to 180 g of pure water, and a vacuum stirring defoaming mixer (manufactured by EM Co.) as a planetary stirring device. Was stirred under reduced pressure to obtain a water-in-oil emulsion. This emulsion was quickly transferred to a reaction vessel and allowed to polymerize at 60 ° C. for 24 hours in a static state after sealing. After completion of the polymerization, the content was taken out, extracted with methanol, and then dried under reduced pressure to produce Monolith Intermediate (2) B having a continuous macropore structure. The internal structure of the monolith intermediate (dry body) thus obtained was observed by SEM. As a result, although the wall section that divides two adjacent macropores is extremely thin and rod-shaped, it has an open cell structure, and the average diameter of the openings (mesopores) where macropores and macropores overlap is measured by mercury porosimetry. Was 40 μm and the total pore volume was 18.2 mL / g.

(Manufacture of second monolith)
Next, 216.6 g of styrene, 4.4 g of divinylbenzene, 220 g of 1-decanol, and 0.8 g of 2,2′-azobis (2,4-dimethylvaleronitrile) were mixed and dissolved uniformly (step II). Next, the above monolith intermediate is placed in a reaction vessel, immersed in the styrene / divinylbenzene / 1-decanol / 2,2′-azobis (2,4-dimethylvaleronitrile) mixture, and degassed in a vacuum chamber. The reaction vessel was sealed and allowed to polymerize at 50 ° C. for 24 hours. After completion of the polymerization, the content was taken out, subjected to Soxhlet extraction with acetone, and then dried under reduced pressure (step III) to obtain a second monolith B.
The internal structure of the second monolith B (dry body) containing 1.2 mol% of the crosslinking component composed of the styrene / divinylbenzene copolymer thus obtained was observed by SEM. As a result, the monolith had a co-continuous structure in which the skeleton and the vacancies were three-dimensionally continuous, and both phases were intertwined. Moreover, the average thickness of the skeleton measured from the SEM image was 20 μm. Further, the average diameter of the three-dimensionally continuous pores of the monolith measured by mercury porosimetry was 70 μm, and the total pore volume was 4.4 mL / g. The average diameter of the pores is a maximum value of the pore distribution curve obtained by the mercury intrusion method.

(Production of second monolith cation exchanger)
The monolith produced by the above method was put into a column reactor, and a solution consisting of 500 g of chlorosulfonic acid and 4 L of dichloromethane was passed through and reacted at 20 ° C. for 3 hours. After completion of the reaction, methanol was added to the system to deactivate unreacted chlorosulfonic acid, and further washed with methanol to take out the product. Finally, it was washed with pure water to obtain a second monolith cation exchanger B.
The obtained monolith cation exchanger had a cation exchange capacity of 4.7 mg equivalent / g in a dry state, and it was confirmed that sulfonic acid groups were quantitatively introduced. Further, when the internal structure of the second monolith cation exchanger B was observed by SEM, the monolith cation exchanger had a co-continuous structure in which the skeleton and the vacancies were each three-dimensionally continuous and the two phases were intertwined. . The average thickness of the skeleton in the dry state measured from the SEM image is 20 μm, and the average in the dry state of the three-dimensional continuous pores of the monolith cation exchanger determined from the measurement by the mercury intrusion method. The diameter was 70 μm, and the total pore volume in the dry state was 4.4 mL / g.
Subsequently, in order to confirm the distribution state of the sulfonic acid group in the second monolith cation exchanger B, the distribution state of sulfur was observed by EPMA. Sulfur was uniformly distributed not only on the skeleton surface of the monolith cation exchanger but also inside the skeleton, and it was confirmed that sulfonic acid groups were uniformly introduced into the monolith cation exchanger.

Example 1
The second monolith cation exchanger B obtained as described above was brought into contact with a large excess of ether and then dried under reduced pressure at room temperature.
Next, 0.5 mmol of benzoic acid and 61 mg of the second monolith cation exchanger B after drying having the same weight as benzoic acid were added to the reaction vessel, and 0.5 mL of toluene was added. At this time, the equivalent ratio of carboxylic acid to the monolithic organic porous cation exchanger (carboxyl group equivalent / cation exchange group equivalent) was 1.7.
Next, methanol was added to the reaction vessel in an equivalent ratio of benzoic acid to a 5-fold equivalent, and 0.5 mL of toluene was further added.
Subsequently, the reaction container was heated at 60 degreeC for 24 hours, and reaction was performed.
After the completion of the reaction, the amount of ester compound produced was analyzed, and the esterification rate was 98%.

(Comparative Example 1)
The second monolith cation exchanger B obtained as described above was brought into contact with a large excess of ether and then dried under reduced pressure at room temperature.
Next, 0.5 mmol of benzoic acid was added to the reaction vessel, and then 61 mg of the second monolith cation exchanger B after drying having the same weight as benzoic acid was added, and then 5 times equivalent in terms of equivalent ratio to benzoic acid. Min methanol was added and stirred. Then 1 mL of toluene was added. At this time, the equivalent ratio of carboxylic acid to the monolithic organic porous cation exchanger (carboxyl group equivalent / cation exchange group equivalent) was 1.7.
Subsequently, the reaction container was heated at 60 degreeC for 24 hours, and reaction was performed.
After the completion of the reaction, the amount of ester compound produced was analyzed, and the esterification rate was 87%.

(Example 2)
The same procedure as in Example 1 was performed except that 0.5 mmol of 4-cyanobenzoic acid was used instead of 0.5 mmol of benzoic acid, and 10 equivalents of methanol instead of 5 equivalents of methanol. As a result, the esterification rate was 95%.

(Comparative Example 2)
Instead of 0.5 mmol of benzoic acid, 0.5 mmol of 4-cyanobenzoic acid was added, and 73 mg of the second monolith cation exchanger B after drying having the same weight as 4-cyanobenzoic acid was added, and methanol 5 It replaced with the equivalent part and performed similarly to the comparative example 1 except setting it as the methanol 10 equivalent part. As a result, the esterification rate was 84%.

(Example 3)
Instead of 0.5 mmol of benzoic acid, 0.5 mmol of 4-ethoxybenzoic acid was added, 83 mg of the second monolith cation exchanger B after drying having the same weight as 4-ethoxybenzoic acid was added, and methanol 5 The same procedure as in Example 1 was performed except that 10 equivalents of methanol were used instead of equivalents. As a result, the esterification rate was 68%.

Example 4
Implemented except that instead of 0.5 mmol of benzoic acid, 0.5 mmol of 4-ethoxybenzoic acid was added and 83 mg of the second monolith cation exchanger B after drying was dried in the same weight as 4-ethoxybenzoic acid. Performed as in Example 1. As a result, the esterification rate was 42%.

(Comparative Example 3)
Instead of adding 0.5 mg of 4-ethoxybenzoic acid instead of 0.5 mmol of benzoic acid and adding 83 mg of the second monolith cation exchanger B after drying in the same weight as 4-ethoxybenzoic acid. The same procedure as in Comparative Example 1 was performed. As a result, the esterification rate was 15%.

(Example 5)
Instead of 0.5 mmol of benzoic acid, 0.5 mmol of 4-t-butylbenzoic acid was added, and 89 mg of the second monolith cation exchanger B after drying having the same weight as 4-t-butylbenzoic acid was added. The same procedure as in Example 1 was conducted except that 10 equivalents of methanol were used instead of 5 equivalents of methanol. As a result, the esterification rate was 79%.

(Example 6)
Instead of 0.5 mmol of benzoic acid, 0.5 mmol of 4-t-butylbenzoic acid was added, and 89 mg of the second monolith cation exchanger B after drying having the same weight as 4-t-butylbenzoic acid was added. Except for this, the same procedure as in Example 1 was performed. As a result, the esterification rate was 56%.

(Comparative Example 4)
Instead of 0.5 mmol of benzoic acid, 0.5 mmol of 4-t-butylbenzoic acid was added, and 89 mg of the second monolith cation exchanger B after drying having the same weight as 4-t-butylbenzoic acid was added. Except for this, the same procedure as in Comparative Example 1 was performed. As a result, the esterification rate was 20%.

1) Number of equivalents of hydroxyl groups relative to the number of equivalents of carboxyl groups

1 Skeletal phase 2 Pore phase 10 Co-continuous structure

Claims (4)

A method for producing an ester compound in which a carboxylic acid and an alcohol are reacted in a solvent in the presence of a monolithic organic porous cation exchanger, and an ester compound is obtained,
When contacting the monolithic organic porous cation exchanger, the carboxylic acid, the alcohol and the solvent, the contact order of the carboxylic acid, the alcohol and the solvent to the monolithic organic porous cation exchanger is as follows: Bringing the alcohol into contact with the monolithic organic porous cation exchanger before the solvent comes into contact;
The manufacturing method of the ester compound characterized by these.   The monolithic organic porous cation exchanger is composed of a continuous skeleton phase and a continuous pore phase, the thickness of the continuous skeleton is 1 to 100 μm, the average diameter of the continuous pores is 1 to 1000 μm, and the total pore volume is 0.5. A monolithic organic porous material having a cation exchange capacity per weight of 1 to 6 mg equivalent / g in a dry state and having a cation exchange group uniformly distributed in the organic porous cation exchanger It is a cation exchanger, The manufacturing method of the ester compound of Claim 1 characterized by the above-mentioned.   The monolithic organic porous cation exchanger has an open cell structure having a common pore (mesopore) having an average diameter of 1 to 1000 μm in the wall of the macropore and the macropore connected to each other, and the total pore volume is 1 A monolithic organic porous material having a cation exchange capacity per weight of 1 to 6 mg equivalent / g in a dry state and having a cation exchange group uniformly distributed in the organic porous cation exchanger It is a cation exchanger, The manufacturing method of the ester compound of Claim 2 characterized by the above-mentioned.   The monolithic organic porous cation exchanger has an average thickness of 1 to 1 composed of an aromatic vinyl polymer containing 0.1 to 5.0 mol% of a crosslinked structural unit among all the structural units into which cation exchange groups have been introduced. A co-continuous structure composed of a three-dimensionally continuous skeleton of 60 μm and three-dimensionally continuous pores having an average diameter of 10 to 200 μm between the skeletons, and a total pore volume of 0.5 to 10 mL Monolithic organic porous cation exchange in which the cation exchange capacity per weight in the dry state is 1 to 6 mg equivalent / g, and the cation exchange groups are uniformly distributed in the organic porous cation exchanger 3. The method for producing an ester compound according to claim 2, wherein the ester compound is a body.