JP2011236134A - Method for producing ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for industrially producing esters usable for fine chemical intermediates, semiconductor resist polymer intermediates, and the like.SOLUTION: In the method for producing esters by transesterification reaction between a raw material ester and a raw material alcohol, a β-diketone iron complex is used as a catalyst. A compound represented by general formula (1) is used for the β-diketone iron complex. In the formula: Rand Rare the same or different and each a hydrocarbon group which may have a substituent; Ris a hydrogen atom or a hydrocarbon group which may have a substituent; R, R, and Rmay be linked mutually to form a ring or connected to a polymer chain; L is an m-valent anion or a ligand; m and n are each an integer of 0 or more; p is an integer of 1 or more; and q is an integer of 0 or more.

Description

  The present invention relates to a method for producing esters, particularly (meth) acrylic acid esters, which are useful as fine chemical intermediates such as pharmaceuticals, agricultural chemicals, polymer materials, functional materials and electronic materials, and semiconductor resist polymer intermediates.

  Conventionally, as a method for producing an ester from a carboxylic acid or a derivative thereof, a method of dehydrating condensation of a carboxylic acid and an alcohol, or a method of reacting an acid halide or acid anhydride with an alcohol is known. However, the dehydration condensation method cannot be applied to an acid-sensitive compound because the system becomes acidic when an acid is used as a catalyst. On the other hand, when a condensing agent such as carbodiimide is used, the system is neutral. However, since the condensing agent is expensive, it is disadvantageous for industrial implementation. In the acid halide or acid anhydride method, a halogen acid, a carboxylic acid or a salt thereof is by-produced. Therefore, it is still difficult to apply to compounds sensitive to acids and bases.

  In order to solve these problems, a transesterification method in which the system is relatively neutral is effective. In the transesterification reaction, an acid such as sulfuric acid or paratoluenesulfonic acid or a base such as an alkali metal alkoxide may be used. In this case, as in the previous method, a compound sensitive to an acid or a base is used. Is not applicable. A typical near neutral catalyst is titanium tetraalkoxide, such as titanium tetraisopropoxide. However, since this catalyst is easily deactivated due to the influence of moisture, there is still room for improvement.

  Several techniques have been proposed to overcome this drawback. For example, it has been reported that a β-diketone chelate compound of zirconium, a β-diketone chelate compound of calcium, and a β-diketone chelate compound of hafnium are effective as a transesterification reaction catalyst (see Patent Documents 1 to 3). However, zirconium and hafnium are relatively expensive metal species, and are hardly said to be advantageous for implementation on an industrial scale. Moreover, since calcium is basic, it cannot be applied to compounds sensitive to bases.

  On the other hand, Patent Document 4 and Patent Document 5 use a compound containing tin or titanium as a catalyst, and Patent Document 6 uses a biocatalyst to produce a (meth) acrylic ester by a transesterification method. A method is disclosed. By these methods, for example, 5-oxooxolan-3-yl = (meth) acrylate can be produced from (meth) acrylic acid ester and 4-hydroxy-dihydrofuran-2-one. However, the problem that the compound containing tin or titanium is sensitive to water has not been solved. Biocatalysts are stable to water, but are not always readily available and are not advantageous for industrial practice.

Japanese Patent Publication No.59-38935 Japanese Patent Publication No. 60-3293 Japanese Patent Laid-Open No. 4-217461 JP 2001-247513 A Japanese Patent No. 3989265 International Publication No. 03/025194 Pamphlet

  The object of the present invention is to industrially produce esters, particularly (meth) acrylic esters, useful as fine chemical intermediates such as pharmaceuticals, agricultural chemicals, polymer materials, functional materials, electronic materials, and semiconductor resist polymer intermediates. An object of the present invention is to provide a method that can be efficiently manufactured.

  As a result of intensive studies to achieve the above object, the present inventors have found that the β-diketone complex of iron is extremely excellent as a catalyst for transesterification, particularly transesterification using (meth) acrylic acid ester as a raw material. I found. The present invention has been completed based on these findings and further research.

  That is, the present invention provides a method for producing an ester characterized in that an iron β-diketone complex is used as a catalyst in a method for producing an ester by a transesterification reaction between a raw material ester and a raw material alcohol.

（式中、Ｒ¹、Ｒ³は、同一又は異なって、置換基を有していてもよい炭化水素基を示し、Ｒ²は水素原子又は置換基を有していてもよい炭化水素基を示す。Ｒ¹、Ｒ²、Ｒ³は、それぞれ互いに結合して環を形成していてもよく、高分子鎖に結合していてもよい。Ｌはｍ価のアニオン又は配位子を示す。ｍ、ｎは、それぞれ０以上の整数、ｐは１以上の整数、ｑは０以上の整数を示す。ｐ、ｑがそれぞれ２以上の場合、複数個の括弧内の化合物又はイオンは、それぞれ同一であっても異なっていてもよい）
で表される化合物を使用できる。鉄のβ−ジケトン錯体としては、鉄の２，４−ペンタンジオン錯体が好ましい。 As the β-diketone complex of iron, the following formula (1)

(Wherein R ¹ and R ³ are the same or different and each represents a hydrocarbon group which may have a substituent, and R ² represents a hydrogen atom or a hydrocarbon group which may have a substituent. R ¹ , R ² and R ³ may be bonded to each other to form a ring or may be bonded to a polymer chain, and L represents an m-valent anion or ligand. m and n are each an integer of 0 or more, p is an integer of 1 or more, and q is an integer of 0 or more, and when p and q are each 2 or more, a plurality of compounds or ions in parentheses are the same. Or it may be different)
The compound represented by these can be used. The iron β-diketone complex is preferably an iron 2,4-pentanedione complex.

  In the said manufacturing method, you may manufacture the (meth) acrylic acid ester corresponding to raw material alcohol, using (meth) acrylic acid ester as raw material ester. Moreover, you may manufacture ester which has cyclic skeleton using alcohol which has cyclic skeleton as raw material alcohol.

  Alternatively, (meth) acrylic acid ester and 4-hydroxy-dihydrofuran-2-one may be reacted to produce 5-oxooxolan-3-yl = (meth) acrylate.

  According to the present invention, since a β-diketone complex of iron is used as a catalyst, it can be applied to a compound sensitive to an acid or a base and is not easily deactivated by water. And can be manufactured efficiently. In addition, since the catalyst is inexpensive and readily available, it is extremely advantageous for producing esters on an industrial scale.

The present invention is characterized in that an iron β-diketone complex is used as a catalyst in a method for producing a target ester by a transesterification reaction between a raw material ester and a raw material alcohol.
The transesterification reaction is represented by the following formula (2).
R ^a COOR ^b + R ^c OH → R ^a COOR ^c + R ^b OH (2)
In the above formula (2), R ^a COOR ^b represents a raw material ester, R ^c OH represents a raw material alcohol, R ^a COOR ^c represents a target ester, and R ^b OH represents a by-product alcohol. R ^a represents a hydrogen atom or an organic group (a hydrocarbon group, a heterocyclic group, a group in which two or more of these are bonded, or the like). R ^b and R ^{c each} represents an organic group having a carbon atom at a bonding site with an adjacent oxygen atom (hydrocarbon group, heterocyclic group, group in which two or more of these are bonded, or the like).

[Raw material ester]
In the present invention, a carboxylic acid ester having a carboxylic acid moiety [corresponding to R ^a CO in the above formula (2)] identical to the carboxylic acid moiety of the target compound is used as the ester used as a raw material.

  Carbon number of the carboxylic acid site | part of carboxylic acid ester is 1-30, for example, Preferably it is 1-20, More preferably, it is about 3-20 (for example, 3-10) grade. The number of carbon atoms in the alcohol moiety of the carboxylic acid ester is about 1 to 8 (especially 1 to 4) in terms of the availability of the carboxylic acid ester and the ease of separation of the by-product alcohol after the transesterification reaction. Is preferred. Moreover, it is desirable that the alcohol by-produced by transesterification (alcohol corresponding to the alcohol portion of the raw material ester) has a lower boiling point or lower molecular weight than the raw material alcohol from the viewpoint of ease of separation. Carbon number of the whole carboxylic acid ester is 2-40, for example, Preferably it is 2-25, More preferably, it is about 4-20 (for example, 4-15).

  Examples of the carboxylic acid ester include aliphatic carboxylic acid esters, alicyclic carboxylic acid esters, aromatic carboxylic acid esters, and heterocyclic carboxylic acid esters. The carboxylic acid ester may be a monocarboxylic acid ester or a polyvalent carboxylic acid ester such as a dicarboxylic acid ester.

  Examples of the aliphatic carboxylic acid ester include formic acid ester, acetic acid ester, propionic acid ester, butyric acid ester, isobutyric acid ester, pentanoic acid ester, hexanoic acid ester, heptanoic acid ester, octanoic acid ester, decanoic acid ester, and dodecanoic acid ester. Saturation of about 1 to 40 carbon atoms such as tetradecanoic acid ester, hexadecanoic acid ester, octadecanoic acid ester, oxalic acid diester, malonic acid diester, succinic acid diester, glutaric acid diester, adipic acid diester, suberic acid diester, sebacic acid diester Aliphatic carboxylic acid esters; acrylic acid esters, methacrylic acid esters, crotonic acid esters, oleic acid esters, maleic acid diesters, fumaric acid diesters, etc. An ester of an aliphatic carboxylic acid.

  Examples of the alicyclic carboxylic acid ester include esters of alicyclic carboxylic acid having about 4 to 40 carbon atoms such as cyclopentane carboxylic acid ester, cyclohexane carboxylic acid ester, and adamantane carboxylic acid ester.

  Examples of the aromatic carboxylic acid ester include carbons such as benzoic acid ester, toluic acid ester, p-chlorobenzoic acid ester, p-methoxybenzoic acid ester, phthalic acid diester, isophthalic acid diester, terephthalic acid diester, and cinnamic acid ester. Examples include esters of aromatic carboxylic acids having a number of about 7 to 40.

  As the heterocyclic carboxylic acid ester, a heterocyclic ring containing at least one hetero atom selected from nitrogen atom, oxygen atom and sulfur atom such as nicotinic acid ester, isonicotinic acid ester, furan carboxylic acid ester and thiophene carboxylic acid ester And a heterocyclic carboxylic acid ester having about 4 to 40 carbon atoms.

  The present invention is particularly useful when an unsaturated carboxylic acid ester having an ethylenic double bond at the carboxylic acid site, particularly a (meth) acrylic acid ester, is used as the raw material ester.

The alcohol moiety of the carboxylic acid ester used as a raw material [corresponding to OR ^b in the above formula (2)] is not particularly limited. For example, as carboxylic acid ester, methyl ester, ethyl ester, propyl ester, isopropyl ester, butyl ester, isobutyl ester, s-butyl ester, t-butyl ester, amyl ester, isoamyl ester, t-amyl ester, hexyl ester, octyl Examples include alkyl esters such as esters; alkenyl esters such as vinyl esters, allyl esters, and isopropenyl esters; cycloalkyl esters such as cyclopentyl esters and cyclohexyl esters; aryl esters such as phenyl esters; and aralkyl esters such as benzyl esters.

  As the carboxylic acid ester, a linear or branched alkyl ester having 1 to 8 carbon atoms (especially 1 to 4 carbon atoms) and a linear or branched alkyl ester having 2 to 8 carbon atoms (especially 2 to 4 carbon atoms). Alkenyl esters are preferred.

In the present invention, as the raw material ester, an unsaturated carboxylic acid C _1-8 alkyl ester or C _2-8 alkenyl ester is particularly preferable. Among them, (meth) acrylic acid C _1-8 alkyl ester or C _2-8 alkenyl is preferable. Esters are preferred.

[Raw alcohol]
In this invention, it does not specifically limit as alcohol used as a raw material, A wide alcohol can be used and any of a primary alcohol, a secondary alcohol, and a tertiary alcohol may be sufficient. The raw material alcohol may be any of monohydric alcohol, dihydric alcohol, and trihydric or higher polyhydric alcohol. Even when an alcohol having a bulky group, such as an alcohol having a cyclic skeleton or a tertiary alcohol, is used as the raw material alcohol, the reaction proceeds smoothly. Carbon number of raw material alcohol is 2-30, for example, Preferably it is 3-25, More preferably, it is about 4-20.

The raw material alcohol may have a substituent (functional group) other than a hydroxyl group on the carbon skeleton. The substituent is not particularly limited as long as it does not impair the reaction. For example, a halogen atom (bromine, chlorine, fluorine atom, etc.), an alkoxy group (C _1-10 alkoxy group such as methoxy, ethoxy, propoxy group, etc.), Hydroxyl groups protected with protecting groups, mercapto groups, alkylthio groups (C _1-10 alkylthio groups such as methylthio, ethylthio, propylthio groups, etc.), alkoxycarbonyl groups (C _1- such as methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl groups, etc.) ₁₀ alkoxy-carbonyl group), acyl group (C _1-10 acyl group such as acetyl, propionyl group, etc.), substituted or unsubstituted amino group (amino group; methylamino, dimethylamino, ethylamino, diethylamino, propylamino, mono- or di-C _1-6 alkyl-substituted amino groups such as di-propylamino group 1-pyrrolidinyl, piperidino, and cyclic amino groups such as morpholino group), an amino group protected by a protective group, a carboxyl group, a cyano group, a nitro group, a sulfonic acid group, a sulfonic acid ester group. Examples of the protecting group in the hydroxyl group protected by the protecting group include a protecting group commonly used in the field of organic synthesis, such as an aralkyl group (for example, benzyl group), a substituted methyl group (for example, methoxymethyl, methoxythiomethyl, Benzyloxymethyl, t-butoxymethyl, 2-methoxyethoxymethyl group, etc.), substituted ethyl groups (eg 1-ethoxyethyl, 1-methyl-1-methoxyethyl etc.), acyl groups (eg formyl, acetyl, propionyl) C _1-6 aliphatic acyl groups such as butyryl, isobutyryl, valeryl and pivaloyl groups; acetoacetyl groups; aromatic acyl groups such as benzoyl and naphthoyl groups], alkoxycarbonyl groups (for example, methoxycarbonyl, ethoxycarbonyl, t - C _1-4 alkoxy such as butoxycarbonyl group Etc. carbonyl group), an aralkyloxycarbonyl group (e.g., benzyloxycarbonyl group, etc. p- methoxybenzyloxycarbonyl group), and others. Examples of the protecting group in the amino group protected by the protecting group include the aralkyl group, acyl group, alkoxycarbonyl group, and aralkyloxycarbonyl group exemplified as the protecting group for the hydroxyl group.

Moreover, the raw material alcohol may have 1 or 2 or more cyclic skeletons in the molecule. The “ring” constituting the cyclic skeleton includes a monocyclic or polycyclic non-aromatic or aromatic ring. As the monocyclic non-aromatic ring, for example, about 3 to 15-membered cycloalkane ring such as cyclopentane ring, cyclohexane ring, cyclooctane ring and cyclodecane ring; about 3 to 15 member such as cyclopentene ring and cyclohexene ring A non-aromatic heterocyclic ring having about 3 to 15 members such as an oxirane ring, an oxetane ring, an oxolane ring (tetrahydrofuran ring), an oxane ring, an oxepane ring, a pyrrolidine ring, a piperidine ring, a morpholine ring and a thiolane ring. For example, a non-aromatic heterocyclic ring having at least one hetero atom selected from an oxygen atom, a nitrogen atom, and a sulfur atom). Examples of the polycyclic non-aromatic ring include an adamantane ring; a norbornane ring, a norbornene ring, a bornane ring, an isobornane ring, a tricyclo [5.2.1.0 ^2,6 ] decane ring, and a tetracyclo [4.4. 0.1 ^2,5 . ^1,7,10 ] ring containing norbornane ring or norbornene ring such as dodecane ring; perhydroindene ring, decalin ring (perhydronaphthalene ring), perhydrofluorene ring (tricyclo [7.4.0.0 ^3,8 ] Tridecane ring), a ring in which a polycyclic aromatic condensed ring such as perhydroanthracene ring is hydrogenated (preferably a fully hydrogenated ring); a tricyclo [4.2.2.1 ^2,5 ] undecane ring, etc. And a bridged carbocyclic ring (for example, a bridged carbocyclic ring having about 6 to 20 carbon atoms). The monocyclic or polycyclic aromatic ring is selected from aromatic carbon rings such as benzene ring, naphthalene ring, pyridine ring, quinoline ring, aromatic heterocyclic ring (for example, oxygen atom, nitrogen atom, sulfur atom) And aromatic heterocycles having at least one heteroatom).

The ring constituting the cyclic skeleton includes an oxo group (═O), an alkyl group such as a methyl group (eg, C _1-4 alkyl group), and a haloalkyl group such as a trifluoromethyl group (eg, C _1-4 A haloalkyl group and the like, and a substituent such as the group exemplified as the substituent which may be bonded to the carbon skeleton.

When the raw material alcohol has a cyclic skeleton, the hydroxyl group may be directly bonded to the ring constituting the cyclic skeleton, or may be bonded via a linking group. Examples of such a linking group include linear or branched alkylene groups such as methylene, methylmethylene, dimethylmethylene, ethylene, propylene, and trimethylene groups; carbonyl groups; oxygen atoms (ether bonds; —O—) Oxycarbonyl group (ester bond; —COO—); aminocarbonyl group (amide bond; —CONH—); and a group in which a plurality of these are bonded. Preferred linking groups include linear or branched C _1-6 alkylene groups (particularly C _1-3 alkylene groups) and the like. For example, the substituents exemplified as the substituents that the ring constituting the cyclic skeleton may have may be bonded to the linking group. In addition, when the raw alcohol has a plurality of cyclic skeletons, the cyclic skeletons may be bonded by a single bond or may be bonded via the above linking group.

  Typical examples of the raw material alcohol include, for example, 1-butanol, 2-butanol, t-butanol, amyl alcohol, t-amyl alcohol, 1-hexanol, 2-hexanol, 1-octanol, and 2-ethyl-1-hexanol. , Aliphatic alcohols (with substituents) such as isodecyl alcohol, lauryl alcohol, cetyl alcohol, stearyl alcohol, ethylene glycol, 1,3-butanediol, trimethylolpropane, dimethylaminoethanol, diethylaminoethanol, dipropylaminoethanol Cyclopentyl alcohol, cyclohexyl alcohol, methylcyclohexyl alcohol, dimethylcyclohexyl alcohol, cyclohexenyl alcohol, cyclopentylmethyl alcohol Cyclohexylmethyl alcohol, dicyclodecyl alcohol, tricyclodecyl alcohol, 1-adamantanol, adamantanemethanol, 1-adamantyl-1-methylethyl alcohol, 1-adamantyl-1-methylpropyl alcohol, 2-methyl-2-adaman Alcohols having an alicyclic ring (alicyclic alcohol) such as tanol, 2-ethyl-2-adamantanol, bornyl alcohol, isobornyl alcohol; benzyl alcohol, methylbenzyl alcohol, 1-phenylethanol, 2-phenylethanol, etc. Aromatic alcohols (including those having a substituent); furfuryl alcohol, tetrahydrofurfuryl alcohol, 4-hydroxy-dihydrofuran-2-one (= β-hydroxy-γ-butyrolactone) 4-hydroxy-4-methyl-dihydrofuran-2-one (= β-hydroxy-β-methyl-γ-butyrolactone), 3-hydroxy-dihydrofuran-2-one (= α-hydroxy-γ-butyrolactone), Lactic alcohols such as mevalolactone (lactone ring-containing alcohols), oxygen-containing heterocyclic alcohols such as oxirane ring-containing alcohols such as glycidyl alcohol; nitrogen-containing heterocyclic alcohols such as oxazolidinylethyl alcohol; sulfur-containing compounds such as tenylmethyl alcohol Examples include heterocyclic alcohols.

  Among the above, the present invention, as a raw material alcohol, high yields are often not obtained by conventional transesterification, alicyclic alcohol, oxygen-containing heterocyclic alcohol, nitrogen-containing heterocyclic alcohol, sulfur-containing heterocyclic ring This is particularly useful when an alcohol having a cyclic skeleton such as alcohol (particularly an alcohol having a non-aromatic cyclic skeleton) is used.

[Β-diketone complex of iron]
In the present invention, an iron β-diketone complex is used as a catalyst. Examples of the iron β-diketone complex include the compound represented by the formula (1). In this compound, a β-diketone or its ion is coordinated or bonded to an iron atom or ion. In the formula (1), R ¹ and R ³ are the same or different and represent a hydrocarbon group which may have a substituent, and R ² represents a carbon atom which may have a hydrogen atom or a substituent. Indicates a hydrogen group. R ¹ , R ² and R ³ may be bonded to each other to form a ring, or may be bonded to a polymer chain. L represents an m-valent anion or ligand. m and n are each an integer of 0 or more, p is an integer of 1 or more, and q is an integer of 0 or more. When p and q are each 2 or more, a plurality of compounds or ions in parentheses may be the same or different.

Examples of the “hydrocarbon group” in the hydrocarbon group optionally having a substituent for R ¹ , R ² , and R ³ include an aliphatic hydrocarbon group, an alicyclic hydrocarbon group, and an aromatic hydrocarbon group. And a group in which a plurality of these are bonded. Examples of the aliphatic hydrocarbon group include alkyl groups such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, s-butyl, t-butyl, and hexyl groups (C _1-6 alkyl groups and the like); An alkenyl group ( _C2-6 alkenyl group etc.) etc. are mentioned. Examples of alicyclic hydrocarbon groups include cycloalkyl groups such as cyclopentyl and cyclohexyl groups (3 to 15 membered cycloalkyl groups); cycloalkenyl groups such as cyclohexenyl groups (3 to 15 membered cycloalkenyl groups and the like) ); A bridged carbocyclic group such as an adamantyl group (such as a bridged carbocyclic group having about 6 to 20 carbon atoms). Examples of the aromatic hydrocarbon group include aromatic hydrocarbon groups having about 6 to 20 carbon atoms (aryl groups) such as phenyl, tolyl, and naphthyl groups.

Examples of the substituent which the hydrocarbon group may have include, for example, halogen atoms such as fluorine, chlorine and bromine atoms; alkoxy such as methoxy, ethoxy, propoxy, isopropyloxy, butoxy, isobutyloxy and t-butyloxy groups group (C _1-4 alkoxy group); a hydroxyl group; methoxy carbonyl, alkoxycarbonyl groups such as ethoxycarbonyl group (C _1-4 alkoxy - carbonyl group); acetyl, propionyl, acyl groups such as benzoyl group (C _{1 -10} acyl group); cyano group; nitro group and the like.

Examples of the ring formed by combining R ¹ , R ² , and R ³ with each other include, for example, a 5- to 15-membered cycloalkane ring or cycloalkene ring such as a cyclopentane ring, a cyclopentene ring, a cyclohexane ring, and a cyclohexene ring. Is mentioned.

Examples of the polymer chain to which R ¹ , R ² and R ³ may be bonded include an acrylic polymer chain, an olefin polymer chain, a styrene polymer chain, a polyester polymer chain, a polyamide polymer chain, a polycarbonate polymer chain, Examples include polyimide polymer chains.

R ¹ and R ³ include an alkyl group (C _1-6 alkyl group etc.), an alkenyl group (C _2-6 alkenyl group etc.), a cycloalkyl group (3-15 membered cycloalkyl group etc.), a cycloalkenyl group. (3- to 15-membered cycloalkenyl group etc.), aryl group (C _6-15 aryl group etc.), aryl group having a substituent (C ₆ having a substituent such as p-methylphenyl group, p-hydroxyphenyl group) _-15 aryl group). R ² includes a hydrogen atom, an alkyl group (C _1-6 alkyl group etc.), an alkenyl group (C _2-6 alkenyl group etc.), a cycloalkyl group (3-15 membered cycloalkyl group etc.), a cycloalkenyl group. (3- to 15-membered cycloalkenyl group etc.), aryl group (C _6-15 aryl group etc.), aryl group having a substituent (C ₆ having a substituent such as p-methylphenyl group, p-hydroxyphenyl group) _-15 aryl group).

  In the compound represented by the formula (1), the valence n of iron may be any of 0 valent, 1 valent, 2 valent, 3 valent, etc., but is usually divalent or trivalent. When iron is divalent or trivalent, the β-diketone is coordinated as the corresponding anion. The coordination number can be any number from 1 to n, where n is the valence of iron. L is an arbitrary anion or ligand, and the coordination number varies depending on its own valence m and the values of p and n.

Examples of L include hydroxyl ion, alkoxy ion (C _1-6 alkoxy ion, etc.), chlorine ion, bromine ion, iodine ion, carboxylate ion (acetate ion, propionate ion, etc., C _1-15 carboxylate ion, etc. Etc.). In addition to these anions, water, solvent, acetylacetone, ammonia and the like may be hydrated, solvated and coordinated.

  When iron is trivalent, 1, 2 or 3 β-diketones can be bonded. In the case of one or two, L is coordinated in addition.

Representative examples of iron β-diketone complexes include Fe (II) (acac) ₂ , Fe (III) (acac) ₃ , Fe (III) (acac) ₂ (OH ⁻ ) ₁ , Fe (III) ( for example, acac) ₁ (OH ⁻ ) ₂ . Here, “acac” represents acetylacetonate.

  As the iron β-diketone complex, a commercially available one may be used as it is or after purification, or it may be prepared and used. It can also be generated and used in a reaction system. When it is generated in the reaction system, for example, iron chloride, hydroxide and β-diketone such as acetylacetone may be added. At this time, a base such as ammonia, amines, alkali metal or alkaline earth metal hydroxides, carbonates or carboxylates can be added as necessary.

  The amount of iron β-diketone complex used as a catalyst can be appropriately adjusted depending on the type of reaction component, and the like, for example, with respect to 1 mol of raw material ester or raw material alcohol (particularly with respect to 1 mol of raw material alcohol). The amount is usually 0.0001 to 10 mol, preferably 0.001 to 1 mol, particularly preferably about 0.001 to 0.2 mol.

[Manufacture of esters]
The transesterification reaction between the raw material ester and the raw material alcohol can be carried out in the presence or absence of a solvent. In the case where no solvent is used, this includes the case where a raw material ester, a raw material alcohol or a β-diketone used as a ligand for a catalyst is used in a solvent amount. When a solvent is used, examples of the solvent include ether solvents such as diethyl ether, diisopropyl ether, dibutyl ether, tetrahydrofuran, dioxane, 1,2-dimethoxyethane, cyclopentyl methyl ether (CPME); acetonitrile, benzonitrile, and the like. Nitriles; sulfoxide solvents such as dimethyl sulfoxide; sulfolanes such as sulfolane; amide solvents such as dimethylformamide; saturated or unsaturated aliphatic hydrocarbon solvents such as pentane, hexane, heptane, octane, petroleum ether; benzene , Toluene, xylene and other aromatic hydrocarbon solvents; methylene chloride, chloroform, 1,2-dichloroethane, chlorobenzene, bromobenzene and other halogenated hydrocarbon solvents; polyethylene Recall, high boiling point solvent such as a silicone oil (boiling point 160 ° C. or more solvents) can be used. Of these, ether solvents such as tetrahydrofuran and cyclopentyl methyl ether (CPME) and aromatic hydrocarbon solvents such as toluene can be particularly preferably used. A solvent can be used individually or in mixture of 2 or more types.

   The amount of the solvent used is not particularly limited as long as it can dissolve or disperse the reaction components and does not impair the economy. For example, with respect to 100 parts by weight of raw material ester or raw material alcohol to be supplied to the reaction system (particularly with respect to 100 parts by weight of raw material alcohol), it is usually selected from the range of about 1 to 100,000 parts by weight, preferably about 1 to 10,000 parts by weight. can do.

  The amount of the raw material ester used is not particularly limited, and can be appropriately selected in consideration of reactivity, operability, economic rationality, and the like. Generally, the usage-amount of raw material ester is about 0.1-100 mol with respect to 1 mol of raw material alcohol, Preferably it is 1-20 mol, More preferably, it is about 1.5-10 mol. When the reaction component or product has a polymerizable group such as a (meth) acryloyl group, a conventional polymerization inhibitor such as phenothiazine may be present in the reaction system as necessary.

  The reaction is often performed under normal pressure or reduced pressure (for example, about 0.0001 to 0.1 MPa, preferably about 0.001 to 0.1 MPa). Alternatively, the reaction may be performed under pressure for operational reasons. The reaction temperature is usually in the range of 40 to 150 ° C, preferably 60 to 120 ° C.

  The reaction may be carried out by any of batch, semi-batch and continuous methods. During the reaction, when the raw material ester is added to the raw material alcohol or vice versa, the components to be added may be added sequentially or intermittently. Since this reaction is an equilibrium reaction, conducting the reaction while continuously separating the by-produced alcohol (derived from the raw ester) or the produced target ester from the reaction system is effective in improving the reaction results. is there. As the means for the separation, a conventional method such as extraction, distillation (azeotropic distillation or the like), rectification, molecular distillation, adsorption, crystallization and the like can be used. For example, a solvent that azeotropes with by-produced alcohol and / or produced ester is present in the reaction system, and the reaction is carried out while distilling off the by-produced alcohol and / or produced ester by azeotropic distillation. Can do. Moreover, when raw material ester and byproduct alcohol azeotrope, you may make it react, distilling this azeotrope using large amount of raw material ester. Separation may be continuous or discontinuous (batch mode).

  In the present invention, after the reaction, the obtained ester may be directly used for the next use or may be used after purification. As a purification method, a conventional method such as extraction, distillation, rectification, molecular distillation, adsorption, crystallization and the like can be used. Purification may be continuous or discontinuous (batch mode).

  EXAMPLES Hereinafter, although an Example demonstrates this invention more concretely, this invention is not limited by these Examples. The reaction results were measured using a gas chromatograph.

Example 1
In a 50 mL reactor, 0.18 g of tris 2,4-pentanedione iron (III) (manufactured by Kanto Chemical Co., Inc.), 5.0 g of methyl methacrylate, and 5000 wt. Of phenothiazine as a polymerization inhibitor with respect to methyl methacrylate. It added so that it might become ppm, and substituted with nitrogen. To this was added 0.5 g of 4-hydroxy-dihydrofuran-2-one (= β-hydroxy-γ-butyrolactone), and the mixture was heated to reflux at 95 ° C. for 6 hours. After completion of the reaction, the reaction solution was cooled and analyzed by gas chromatography. As a result, 5-oxooxolan-3-yl methacrylate (= β-methacryloyloxy-γ-butyrolactone), which was the target ester, was converted into the starting alcohol (4- 38% based on hydroxy-dihydrofuran-2-one).

Example 2
Tris 2,4-pentanedione iron (III) (manufactured by Kanto Chemical Co., Inc.) 0.18 g and methyl methacrylate 5.0 g were added to a reactor having a capacity of 50 mL, and the atmosphere was replaced with nitrogen. To this was added 1.0 g of 4-hydroxy-dihydrofuran-2-one, and the mixture was heated to reflux at 95 ° C. for 6 hours. The water concentration of the reaction crude liquid was 430 ppm by weight. After completion of the reaction, the reaction solution was cooled and analyzed by gas chromatography. As a result, 5-oxooxolan-3-yl methacrylate, which was the target ester, was determined based on the raw material alcohol (4-hydroxy-dihydrofuran-2-one). 23% was produced.

Example 3
In place of tris 2,4-pentanedione iron (III), 0.074 g of iron (III) chloride, 0.15 g of 2,4-pentanedione, and 0.16 g of sodium carbonate were used and reacted in the same manner as in Example 1. Went. The yield of the target ester, 5-oxooxolan-3-yl methacrylate, was 15% based on the starting alcohol.

Example 4
Tris 2,4-pentanedione iron (III) was prepared according to the method of Journal of Chemical Society, Dalton Transaction, page 839 (1989).
Using this tris 2,4-pentanedione iron (III), the reaction was carried out in the same manner as in Example 1. The yield of the desired ester, 5-oxooxolan-3-yl methacrylate, was 22% based on the starting alcohol.

Example 5
A dropping funnel and a cooling pipe were attached to a 500 mL capacity reactor, and an apparatus capable of simultaneously distilling the liquid from the reactor and replenishing the liquid to the reactor was installed. To this reactor, 5.3 g of tris 2,4-pentanedione iron (III) (manufactured by Kanto Chemical Co., Inc.), 150 g of methyl methacrylate, 4-hydroxy-dihydrofuran-2-one (= β-hydroxy-γ-butyrolactone) 30.6 g was charged and the pressure was reduced to 867 hPa. The mixture was heated to 95 ° C. to distill the low-boiling components, and at the same time, the same amount of methyl methacrylate as the distillate was added to the reactor via a dropping funnel every hour. After this operation was continued for 22 hours, the reaction solution was cooled and analyzed by gas chromatography. As a result, 5-oxooxolan-3-yl methacrylate (= β-methacryloyloxy-γ-butyrolactone), which was the target ester, was obtained. 47% was produced based on the raw material alcohol (4-hydroxy-dihydrofuran-2-one).

Comparative Example 1
The reaction was carried out in the same manner as in Example 1 except that 0.20 g of titanium tetraisopropoxide, which is a general transesterification catalyst, was used instead of tris 2,4-pentanedione iron (III). However, the target ester 5-oxooxolan-3-yl methacrylate was not obtained, and the yield was 0%.

Comparative Example 2
In place of tris 2,4-pentanedione iron (III), 0.18 g of di-n-octyltin oxide, which is a transesterification catalyst used in Examples of JP-A-2001-247513, was used. The reaction was carried out in the same manner as above. The yield of the target ester, 5-oxooxolan-3-yl methacrylate, was 15% based on the starting alcohol.

Claims (6)

  A process for producing an ester by a transesterification reaction between a raw material ester and a raw material alcohol, wherein an iron β-diketone complex is used as a catalyst. The β-diketone complex of iron is represented by the following formula (1)

(Wherein R ¹ and R ³ are the same or different and each represents a hydrocarbon group which may have a substituent, and R ² represents a hydrogen atom or a hydrocarbon group which may have a substituent. R ¹ , R ² and R ³ may be bonded to each other to form a ring or may be bonded to a polymer chain, and L represents an m-valent anion or ligand. m and n are each an integer of 0 or more, p is an integer of 1 or more, and q is an integer of 0 or more, and when p and q are each 2 or more, a plurality of compounds or ions in parentheses are the same. Or it may be different)
The method for producing an ester according to claim 1, wherein the compound is represented by the formula:   The method for producing an ester according to claim 1 or 2, wherein the iron β-diketone complex is an iron 2,4-pentanedione complex.   The manufacturing method of the ester in any one of Claims 1-3 which manufactures the (meth) acrylic acid ester corresponding to raw material alcohol using (meth) acrylic acid ester as raw material ester.   The method for producing an ester according to any one of claims 1 to 4, wherein an ester having a cyclic skeleton is produced using an alcohol having a cyclic skeleton as a raw material alcohol.   6. A methacrylic acid ester and 4-hydroxy-dihydrofuran-2-one are reacted to produce 5-oxooxolan-3-yl = (meth) acrylate. The manufacturing method of ester as described in.