JP2012250915A - Manufacturing method for ester compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an excellently productive manufacturing method for an ester compound that generates little waste such as waste water or the like and almost dispenses with or carries out in a shorter time a filtration process after a reaction compared with conventional techniques.SOLUTION: The manufacturing method for an ester compound comprises subjecting an organic acid (C) and a compound (D) bearing a hydroxy group in the molecule to a dehydrative condensation reaction in carbon dioxide (B) of a supercritical state in the presence of a Broensted acid ionic liquid (A). The organic acid (C) is preferably a carboxylic acid. The Broensted acid ionic liquid (A) is preferably the one represented by specific general formulas (1) to (3).

Description

  The present invention relates to a method for producing an ester compound having excellent productivity.

  Various methods for producing an ester compound have been proposed. For example, a method of reacting a carboxylic acid and an alcohol in the presence of an acid catalyst and removing the produced water out of the system (dehydration condensation reaction), and reacting an ester of a carboxylic acid with a lower alcohol and an alcohol to produce a by-product A method of removing the lower alcohol (transesterification reaction) is generally used.

  The dehydration-condensation method has a drawback in that a strong acid such as sulfuric acid and para-toluenesulfonic acid and excess organic acid are removed after the reaction, so that a large amount of waste water is generated by neutralization and washing, and the process is lengthened. .

  The method based on the transesterification reaction requires less wastewater than the dehydration reaction, but is generally insolubilized and filtered by hydrolysis to remove titanium alkoxide, etc., which is usually used for the catalyst. There was a defect that the process was bad and the process was long. On the other hand, a method of adding an inorganic substance having a dehydrating ability and a polymer flocculant has been proposed for the purpose of quickly removing a catalyst such as titanium alkoxide (for example, Patent Document 1). However, a large amount of inorganic substance and polymer flocculant that are added for dehydration are required to be filtered, and the amount of waste such as waste water is somewhat reduced, which is not a preferable method.

JP 2011-037762 A

  An object of the present invention is to provide a method for producing an ester compound that has little productivity such as waste water and that is excellent in productivity and that requires almost no filtration step after reaction or can be performed in a short time.

  The inventors of the present invention have arrived at the present invention as a result of studies to achieve the above object. That is, the present invention provides a dehydration condensation reaction between an organic acid (C) and a compound (D) having a hydroxyl group in the molecule in carbon dioxide (B) in a supercritical state in the presence of a Bronsted acid ionic liquid (A). This is a method for producing an ester compound.

  The production method of the ester compound of the present invention can be carried out in a short time by filtering only a small amount of precipitate, and without producing water out of the system, the waste is only a small amount of waste water. There is an effect that it is excellent in properties.

  The method for producing an ester compound of the present invention comprises a compound (D) having an organic acid (C) and a hydroxyl group in the molecule in carbon dioxide (B) in a supercritical state in the presence of a Bronsted acid ionic liquid (A). And a dehydration condensation reaction.

  The Bronsted acid ionic liquid (A) in the present invention has Bronsted acid groups (for example, a sulfonic acid group, a phosphoric acid group, and a boric acid group that may be substituted) in the molecule, and is liquid at 40 ° C. or lower. Although the structure is not specifically limited, For example, following General formula (1)-(3) etc. are mentioned. Two or more of these may be used in combination.

In the formula, R ^{1 to} R ⁵ , R ^{7 to} R ¹⁰ and R ^{12 to} R ²⁶ are each independently a hydrogen atom, a halogen atom, a monovalent acyl group having 1 to 20 carbon atoms, or 1 having 1 to 20 carbon atoms. A monovalent alkyl group having 1 to 20 carbon atoms, a monovalent alkylthio group having 1 to 20 carbon atoms, a monovalent alkylsilyl group having 1 to 20 carbon atoms, a nitro group, a carboxyl group, a hydroxyl group, An atom or a substituent selected from the group consisting of a mercapto group, an amino group, a cyano group, a phenyl group and a naphthyl group, wherein R ⁶ , R ¹¹ and R ²⁷ are a divalent alkylene group having 1 to 20 carbon atoms; / Or a divalent alkylene oxide group having 1 to 30 carbon atoms, wherein (X1) ⁻ to (X3) ⁻ each represents an anion.

  Examples of the halogen atom include fluorine, chlorine, bromine and iodine, and fluorine and chlorine are preferable.

  Examples of the monovalent acyl group having 1 to 20 carbon atoms include formyl group, acetyl group, propionyl group, isobutyryl group, valeryl group, and cyclohexylcarbonyl group.

  Examples of the monovalent alkyl group having 1 to 20 carbon atoms include methyl group, ethyl group, n- or iso-propyl group, n-, sec- or tert-butyl group, n-, iso- or neo-pentyl group, A hexyl group, a heptyl group, an octyl group, etc. are mentioned.

  Examples of the monovalent alkoxy group having 1 to 20 carbon atoms include methoxy group, ethoxy group, n- or iso-propoxy group, n-, sec- or tert-butoxy group, n-, iso- or neo-pentyl. Examples thereof include an oxy group, a hexyloxy group, a heptyloxy group, and an octyloxy group.

  Examples of the monovalent alkylthio group having 1 to 20 carbon atoms include a methylthio group, an ethylthio group, an n- or iso-propylthio group, an n-, sec- or tert-butylthio group, an n-, iso- or neo-pentylthio group. Hexylthio group, heptylthio group, octylthio group and the like.

  Examples of the monovalent alkylsilyl group having 1 to 20 carbon atoms include trialkylsilyl groups such as trimethylsilyl group and triisopropylsilyl group. Here, the alkyl may be a linear structure or a branched structure.

  Examples of the divalent alkylene group having 1 to 20 carbon atoms include methylene group, ethylene group, n- or iso-propylene group, n-, sec- or tert-butylene group, n-, iso- or neo-pentylylene group, Examples include a hexylene group, a heptylene group, and an octylene group.

  Examples of the divalent alkylene oxide group having 1 to 30 carbon atoms include a diethylene oxide group, a triethylene oxide group, a hexaethylene oxide group, and an octapropylene oxide group.

Among these, from the viewpoint of catalytic ability, in general formula (1), R ^{1 to} R ⁵ are preferably hydrogen atoms, and R ⁶ is preferably an alkylene group having 3 or 4 carbon atoms. In general formula (2), R ⁷ is preferably a hydrogen atom or a methyl group, R ⁸ is an alkyl group having 1 to 4 carbon atoms, R ⁹ and R ¹⁰ are each a hydrogen atom, and R ¹¹ is preferably an alkylene group having 3 or 4 carbon atoms. In 3), R ^{12 to} R ²⁶ are preferably a hydrogen atom, and R ²⁷ is preferably an alkylene group having 3 or 4 carbon atoms.

In the general formulas (1) to (3), examples of the anion represented by (X1) ⁻ to (X3) ⁻ include a halide anion, a hydroxide anion, a thiocyanate anion, and a dialkyl having 1 to 4 carbon atoms. Dithiocarbamate anion, carbonate anion, bicarbonate anion, sulfate anion, hydrogen sulfate anion, aliphatic or aromatic carboxy anion optionally substituted with halogen (benzoate anion, trifluoroacetate anion, perfluoroalkylacetate anion, and Phenylglyoxylate anion, etc.), aliphatic or aromatic sulfoxy anion optionally substituted with halogen (trifluoromethanesulfonate anion and p-toluenesulfonate anion, etc.), hexafluoroantimonate anion (SbF ₆ ⁻ ) Phosphine anion [phosphine hexafluoride On (PF ₆ ^-) and trifluoride tris (perfluoroethyl) phosphine anion _{(PF 3 (C 2 F 5} ) 3 -) , etc.] and borate anion (tetraphenyl borate and butyl triphenyl borate anion, etc.) and the like include Of these, from the viewpoint of catalytic ability, an aliphatic or aromatic sulfoxy anion optionally substituted with halogen and / or an aliphatic or aromatic carboxy anion optionally substituted with halogen are preferable, and halogen An aliphatic or aromatic sulfoxy anion which may be substituted with is more preferred.

  The added amount of Bronsted acid ionic liquid (A) in the present invention is preferably 0.05 with respect to the total weight of organic acid (C) and compound (D) having a hydroxyl group in the molecule from the viewpoint of catalytic ability. It is -300 weight%, More preferably, it is 0.1-200 weight%.

  Although the manufacturing method of Bronsted acid ionic liquid (A) in this invention is not specifically limited, For example, it is 1, 3- propane sultone and 1, 4- propane in 1 mol of pyridine, ethyl imidazole, a triphenyl phosphine, etc., for example. For example, 1 mol of p-toluenesulfonic acid is added after reacting any one mole of butylene sultone or the like to form a salt structure.

  By using the Bronsted acid ionic liquid (A), it is possible to produce an ester compound by a dehydration condensation reaction without going through a step of removing generated water out of the system.

  Carbon dioxide (B) in the supercritical state in the present invention is a compressive fluid that can be found when, for example, the critical temperature (31.0 ° C.) and the critical pressure (7.4 MPa) or higher are satisfied. Furthermore, a supercritical fluid is defined as a non-condensable fluid that exceeds the gas-liquid critical temperature and pressure inherent to the substance. Since the temperature exceeds the critical temperature, the thermal motion of the molecule is intense, and the density can be continuously changed by changing the pressure from a dilute state close to an ideal gas to a high density state corresponding to a liquid. .

  Further, by using carbon dioxide (B) in a supercritical state, the reaction proceeds in a shorter time than usual. The first is to stabilize the transition state of the reaction system and lower the activation energy, and the second is to promote the formation of an ester compound by dehydration condensation because it is a Lewis acid field. Therefore, supercritical nitrogen or the like does not show the effect of promoting such a reaction.

  The temperature during the reaction in carbon dioxide (B) in the present invention is in the supercritical region temperature range of carbon dioxide, and is preferably 31 ° C. to 180 ° C., more preferably 40 from the viewpoint of the reaction rate of the dehydration condensation reaction. ° C to 150 ° C.

The pressure during the reaction in the present invention is in the supercritical region pressure range of carbon dioxide, and is preferably 7.4 to 30 MPa, more preferably 10 to 20 MPa from the viewpoint of reaction rate, side reaction, and simplicity of the apparatus. is there.
Carbon dioxide (B) in the supercritical state is reacted with a Bronsted acid ionic liquid (A), an organic acid (C), a compound having a hydroxyl group in the molecule (D), and a solvent described later if necessary. It is preferable to use an amount that gives the above pressure at the temperature.

  The reaction time in the present invention may be adjusted according to the reaction temperature, but is preferably from 0.1 to 20 hours, more preferably from 0.3 to 20 hours from the viewpoint of productivity.

  Although the organic acid (C) in this invention is not specifically limited, Carboxylic acid, phosphoric acid, and those anhydrides are mentioned, For example, the following (i)-(x) are mentioned. Of these, carboxylic acid is preferred from the viewpoint of reaction efficiency. These may be used alone or in combination of two or more.

(I) an aliphatic monocarboxylic acid having 1 to 30 or more carbon atoms (excluding carbon in the COOH group, the same shall apply hereinafter);
Saturated aliphatic monocarboxylic acids (acetic acid, propionic acid, octylic acid, stearic acid, etc.) and unsaturated aliphatic monocarboxylic acids (acrylic acid, methacrylic acid, lauric acid, etc.).

(Ii) an aliphatic polyvalent (preferably 2 to 8 valent) carboxylic acid having 1 to 30 or more carbon atoms;
Saturated aliphatic polycarboxylic acids (succinic acid, adipic acid, azelaic acid, sebacic acid, etc.) and unsaturated aliphatic polyvalent carboxylic acids (maleic acid, fumaric acid, itaconic acid, citraconic acid, glutaconic acid, etc.).

(Iii) an aromatic monocarboxylic acid having 6 to 30 or more carbon atoms;
Benzoic acid, toluic acid, quinolinecarboxylic acid and p-chlorobenzoic acid.

(Iv) an aromatic polyvalent (preferably 2 to 8 valent) carboxylic acid having 6 to 30 or more carbon atoms;
Isophthalic acid, terephthalic acid, naphthalenedicarboxylic acid and diphenyldicarboxylic acid.

(V) an alicyclic monocarboxylic acid having 3 to 30 carbon atoms;
Cyclopropanecarboxylic acid and cyclobutanecarboxylic acid.

(Vi) an araliphatic carboxylic acid having 7 to 15 or more carbon atoms;
2-phenylethanoic acid, monobenzylacetic acid, 1,2-diphenylhexanoic acid and the like.

(Vii) anhydrides of (i) to (vi);
Maleic anhydride, acrylic anhydride, methacrylic anhydride, phthalic anhydride, tetrahydrophthalic anhydride, hexahydrophthalic anhydride, tetrabromophthalic anhydride, hexabromophthalic anhydride, hymic anhydride, and het acid anhydride.

(Viii) aliphatic phosphoric acid, phosphorous acid, phosphonic acid having 1 to 30 or more carbon atoms;
Aliphatic phosphoric acid (such as methyl phosphoric acid, ethyl phosphoric acid, dimethyl phosphoric acid, diethyl phosphoric acid, methyl ethyl phosphoric acid, dibutyl phosphoric acid, dihexyl phosphoric acid and di (2-ethylhexyl) phosphoric acid), aliphatic phosphorous acid (methyl sublimation) Phosphoric acid, ethyl phosphorous acid, etc.) and aliphatic phosphonic acids (such as methylphosphonic acid and ethylphosphonic acid).

(Ix) Aromatic phosphoric acid, phosphorous acid, phosphonic acid having 6 to 30 or more carbon atoms;
Aromatic aliphatic phosphoric acid (phenylphosphoric acid, pyridylphosphoric acid, p-cresylphosphoric acid di and diphenylphosphoric acid etc.), aromatic phosphorous acid (phenylphosphorous acid and pyridylphosphorous acid etc.) and aromatic phosphonic acid (phenylphosphon) Acid, pyridylphosphonic acid, etc.).

(X) anhydrides of (viii) to (ix);
An anhydride of the above phosphoric acid such as methyl phosphoric acid, ethyl phosphoric acid, phenyl phosphoric acid.

  Although the compound (D) which has a hydroxyl group in the molecule | numerator in this invention is not specifically limited, Low molecular alcohol, polyether alcohol, etc. are mentioned. These may be used alone or in combination of two or more.

  Monovalent low molecular weight alcohols include aliphatic saturated alcohols having 1 to 30 carbon atoms (such as methanol, ethanol, butanol, octanol and stearyl alcohol), aliphatic unsaturated alcohols (allyl alcohol, propenyl alcohol, propargyl alcohol and oleyl alcohol). Etc.) and araliphatic alcohols (benzyl alcohol, etc.).

  Examples of the polyhydric low molecular alcohol include dihydric alcohols having 2 to 30 carbon atoms (ethylene glycol, propylene glycol, 1,2-butanediol, 1,3-butanediol, 1,4-butanediol, 1,6- Hexanediol, 3-methylpentanediol, diethylene glycol, neopentyl glycol, 1,4-bis (hydroxymethyl) cyclohexane, 1,4-bis (hydroxyethyl) benzene and 2,2-bis (4,4'-hydroxycyclohexyl) Propane, etc.), trihydric alcohols having 2 to 30 carbon atoms (such as glycerin and trimethylolpropane) and 4- to 8-valent alcohols having 2 to 30 carbon atoms (pentaerythritol, diglycerin, α-methylglucoside, sorbitol, Xylit, Mannit, Dipentaerythrito , Glucose, fructose and sucrose, etc.) and the like.

Examples of the polyether alcohol include water, the above monovalent and polyvalent low molecular alcohols, phenols having 6 to 30 carbon atoms (phenol, cresol, pyrogallol, catechol, hydroquinone, etc.), bisphenols (bisphenol A, bisphenol F). And bisphenol S, etc.), C1-C30 amino group-containing compounds [ammonia, alkylamine (butylamine, etc.), aniline, alkylenediamine (ethylenediamine, trimethylenediamine, hexamethylenediamine, etc.), polyalkylene polyamine (diethylenetriamine, etc.) Piperazine, N-aminoethylpiperazine, dichloromethanediamine, isophoronediamine, phenylenediamine, tolylenediamine, diethyltolylenediamine, xylylenediamine, diphenyl Condensation of tan diamine, diphenyl ether diamine, polyphenylmethane polyamine, polyamide polyamine [for example, polyvalent carboxylic acid (dimer acid, etc.) and excess (more than 2 mol per mol of acid) polyamine (the above alkylene diamine, polyalkylene polyamine, etc.) Low molecular weight polyamide polyamine obtained by: polyether polyamine [hydride of cyanoethylated polyether alcohol (polyalkylene glycol, etc.)]; cyanoethylated polyamine [eg acrylonitrile and polyamine (alkylenediamine, polyalkylenepolyamine, etc.) Cyanoethylated polyamines obtained by addition reaction, such as biscyanoethyldiethylenetriamine, etc.], hydrazines (hydrazine, monoalkylhydrazine, etc.), di Dragit (succinic acid dihydragit, adipic acid dihydragit, isophthalic acid dihydragit, terephthalic acid dihydragit, etc.), guanidines (butyl guanidine, 1-cyanoguanidine, etc.), dicyandiamide, monoethanolamine, monoisopropanolamine, monobutanolamine, triethanolamine , Quaternized nitrogen atoms with quaternizing agents such as tripropanolamine, N, N-dimethylethanolamine, N, N-diethylethanolamine, N-methyldiethanolamine, N-butyldiethanolamine and dimethylsulfuric acid or benzyl chloride Etc.], carboxylic acids exemplified in the above (i) to (vii) and their anhydrides, thiol group-containing compounds having 1 to 30 carbon atoms (ethylene dithiol, propylene dithiol, etc.) 1,3-butylene dithiol, 1,4-butanedithiol, 1,6-hexanedithiol, 3-methylpentanedithiol, etc.), and the phosphoric acid compounds exemplified in the above (viii) to (x) and their anhydrides An alkylene oxide adduct of an active hydrogen compound selected from the group consisting of
The alkylene oxide preferably has 2 to 4 carbon atoms, more preferably ethylene oxide (EO) or propylene oxide (PO). The number of added moles (per molecule) is not particularly limited, but is preferably 2 to 100 moles.

  In the present invention, the amount of the compound (D) having a hydroxyl group in the molecule is preferably the equivalent of the hydroxyl group of (D) to 1 equivalent of the carboxyl group of the organic acid (C) from the viewpoint of reducing waste. It is -2, More preferably, it is 0.9-1.1.

  In the manufacturing method of the ester compound of this invention, a solvent can be used if necessary. Solvents include hexane, decane, chloroform, ethyl acetate, butyl acetate, acetone, methyl isobutyl ketone, toluene, xylene, N-methyl-2-pyrrolidone, γ-butyrolactone, N, N-dimethylacetamide, dimethyl sulfoxide, diethylene glycol diethyl Examples include ether, diethylene glycol dibutyl ether, propylene glycol dimethyl ether, dipropylene glycol dimethyl ether, propylene glycol monomethyl ether acetate, methyl lactate, ethyl lactate, butyl lactate, cyclohexanone, and cyclopentanone. These may be used alone or in combination of two or more.

  The amount of the solvent used is preferably 0 to 96% by weight, more preferably 3 to 95% by weight, particularly preferably based on the total weight of the organic acid (C) and the compound (D) having a hydroxyl group in the molecule. Is from 5 to 90% by weight.

In the production method of the present invention, carbon dioxide is added to a mixture of the organic acid (C) in the pressure vessel, the compound (D) having a hydroxyl group in the molecule, the Bronsted acid ionic liquid (A), and, if necessary, the solvent. It is preferably introduced so as to be in a supercritical state and subjected to a dehydration condensation reaction at the above temperature, pressure and time.
Since the inside of the container after the reaction is separated into two layers of the generated ester compound layer and the Bronsted acid ionic liquid (A) layer (including generated water, unreacted raw materials, etc.), Separate the two layers. Since a small amount of Bronsted acid ionic liquid (A) is usually dissolved in the ester compound layer, an adsorbent such as silica is added and (A) is adsorbed and filtered to obtain the target ester compound. Is preferred. In addition, the layer of Bronsted acid ionic liquid (A) may separate (A), produced water, and unreacted raw material by distillation or the like, if necessary, and reuse (A) and unreacted raw material. Good.

  EXAMPLES Hereinafter, although an Example demonstrates this invention further, this invention is not limited to these. Hereinafter, “%” represents “% by weight” and “part” represents “part by weight”.

Production Example 1
<Synthesis of Bronsted acid ionic liquid (A-1) [compound represented by the following chemical formula (4)]>
A flask equipped with a stirrer, a gas introduction tube, a cooling tube and a thermometer was charged with 79 parts of pyridine, 136 parts of 1,4-butane sultone and 500 parts of toluene, and stirred at 25 ° C. for 3 hours. It was collected by filtration. By adding 150 parts of trifluoromethanesulfonic acid to 215 parts of the precipitate and kneading, 365 parts of the target Bronsted acid ionic liquid (A-1) [compound represented by the following chemical formula (4)] was obtained. (Yield 100%).

Production Example 2
<Synthesis of Bronsted acid ionic liquid (A-2) [compound represented by the following chemical formula (5)]>
A flask equipped with a stirrer, a gas introduction tube, a cooling tube, and a thermometer was charged with 96 parts of ethylimidazole, 122 parts of 1,3-propane sultone, and 500 parts of toluene, and stirred at 25 ° C. for 3 hours. 218 parts were collected by filtration. 190 parts of p-toluenesulfonic acid was added to 218 parts of the precipitate and kneaded to obtain 390 parts of the target Bronsted acid ionic liquid (A-2) [compound represented by the following chemical formula (5)]. (Yield 100%).

Production Example 3
<Synthesis of Bronsted acid ionic liquid (A-3) [compound represented by the following chemical formula (6)]>
A flask equipped with a stirrer, a gas introduction tube, a cooling tube and a thermometer was charged with 262 parts of triphenylphosphine, 122 parts of 1,3-propane sultone and 500 parts of toluene, and stirred at 25 ° C. for 3 hours. 384 parts were collected by filtration. By adding 114 parts of trifluoroacetic acid to 384 parts of the precipitate and kneading, 498 parts of the target Bronsted acid ionic liquid (A-3) [compound represented by the following chemical formula (6)] was obtained ( Yield 100%).

Example 1
Manufactured in a pressure-resistant reaction kettle equipped with a stirrer, gas introduction tube, cooling tube and thermometer, with 120 parts of acetic acid as organic acid (C) and 106 parts of diethylene glycol as compound (D) having a hydroxyl group in the molecule and Production Example 1 10 parts of the Brönsted acid ionic liquid (A-1) was charged and the temperature was raised to 45 ° C., and then liquefied carbon dioxide was pumped in to set the inside of the reaction vessel to 12 MPa to be in a supercritical state. After reacting for 3 hours with stirring, the mixture was cooled to room temperature and depressurized to atmospheric pressure. Since the inside of the reaction vessel is separated into two layers, a layer of the produced ester compound and a layer containing the Bronsted acid ionic liquid (A-1), an ester compound and a Bronsted acid ionic liquid (A- The mixture containing 1) was separated. Since about 3% of Bronsted acid ionic liquid (A-1) is dissolved in the ester compound, 10 parts of silica powder [“Wakogel C-200” manufactured by Wako Pure Chemical Industries, Ltd.] is added, and 1 ° C. at 25 ° C. After stirring for a period of time, 188 parts of the target ester compound (Q-1; diethylene glycol diacetate) was obtained by absorbing and removing the Bronsted acid ionic liquid (A-1) on silica by filtration (yield 97%). ).
The breakdown of 48 parts of the mixture containing the Bronsted acid ionic liquid (A-1) recovered by the liquid separation operation is as follows: 6 parts of Bronsted acid ionic liquid (A-1), 6 parts of unreacted raw material, and produced water Was 36 parts, but can be divided into “36 parts of waste water”, “6 parts of Bronsted acid ionic liquid (A-1) and 6 parts of unreacted raw material” by distillation operation, and “Bronsted acid ionic liquid ( A-1) 6 parts and 6 parts of unreacted raw material "can be reused for the next reaction. That is, the waste in Example 1 was only a total of 50 parts of “36 parts of waste water” and “14 parts of silica-derived solid used for purification”.

Example 2
“Acetic acid 120 parts” is “Acrylic acid 432 parts”, “Diethylene glycol 106 parts” is “Dipentaerythritol 254 parts”, “Bronsted acid ionic liquid (A-1)” is “Bronsted acid ionic liquid (A -2) "was obtained in the same manner as in Example 1 except that 555 parts of an ester compound (Q-2; dipentaerythritol hexaacrylate) was obtained (yield 96%).
As in Example 1, the waste in Example 2 was only 121 parts in total of “108 parts of waste water” and “13 parts of silica-derived solid material used for purification”.

Example 3
“Acetic acid 120 parts” is “trimellitic acid 210 parts”, “diethylene glycol 106 parts” is “allyl alcohol 174 parts”, and “Bronsted acid ionic liquid (A-1)” is “Bronsted acid ionic liquid (A -3) "except that 380 parts of an ester compound (Q-3; trimellitic acid triallyl ester) was obtained in the same manner as in Example 1 (99% yield).
As in Example 1, the waste in Example 3 was only 68 parts in total: “54 parts of waste water” and “14 parts of silica-derived solid material used for purification”.

Example 4
Example except for changing “120 parts of acetic acid” to “172 parts of methacrylic acid” and “106 parts of diethylene glycol” to “200 parts of polyethylene glycol (number average molecular weight = 200;“ PEG-200 ”manufactured by Sanyo Chemical Industries)” In the same manner as in Example 1, 326 parts of an ester compound (Q-4; polyethylene glycol dimethacrylate) was obtained (yield 97%).
As in Example 1, the waste in Example 4 was only 51 parts in total: “36 parts of waste water” and “15 parts of silica-derived solid used for purification”.

Comparative Example 1 (Reaction in supercritical nitrogen)
Except for changing “liquefied carbon dioxide” to “liquefied nitrogen” in the same manner as in Example 1, the ester compound (Q-1; diethylene glycol diacetate) was not produced when reacted in a supercritical state. It was only raw material recovery (raw material recovery rate 100%).

Comparative Example 2 (Reaction with an ionic liquid having no Bronsted acid group)
A reaction was conducted in the same manner as in Example 1 except that “Bronsted acid ionic liquid (A-1)” was changed to “1-ethyl-3-methylimidazolium hydrogensulfate [manufactured by Tokyo Chemical Industry Co., Ltd.]”. The ester compound (Q-1; diethylene glycol diacetate) was not produced, and only the raw material was recovered (raw material recovery rate 100%).

Comparative Example 3 (Reaction in liquefied carbon dioxide)
The reaction was carried out in the same manner as in Example 1 except that “12 MPa” was changed to “5 MPa” and reacted in liquefied carbon dioxide, and no ester compound (Q-1; diethylene glycol diacetate) was produced. It was only recovery (raw material recovery rate 100%).

Comparative Example 4 (Reaction with Bronsted acid that is not an ionic liquid)
When the reaction was carried out in the same manner as in Example 1 except that “Bronsted acid ionic liquid (A-1)” was changed to “p-toluenesulfonic acid”, 14 parts of an ester compound (Q-1; diethylene glycol diacetate) was added. Obtained (yield 7%).

Comparative Example 5 (ordinary dehydration esterification reaction)
In a flask equipped with a stirrer, a gas introduction tube, a cooling tube and a thermometer, 120 parts of acetic acid as the organic acid (C), 106 parts of diethylene glycol as the compound (D) having a hydroxyl group in the molecule, 1 water of p-toluenesulfonic acid 10 parts of Japanese product and 500 parts of toluene were charged, and the temperature was raised to 120 ° C., followed by reaction for 24 hours while removing generated water from the system. The mixture was cooled to room temperature, washed with 500 parts of a 5% aqueous sodium hydroxide solution and separated. Toluene was removed by distillation under reduced pressure to obtain 188 parts of an ester compound (Q-1; diethylene glycol diacetate) (yield 97%).
The waste in Comparative Example 5 was “waste water 516 parts” (toluene distilled under reduced pressure can be recovered and reused), and more than 10 times the waste of Example 1 was by-produced.

  In the method for producing an ester compound of the present invention, only a small amount of precipitate needs to be filtered, the filtration process is short, and the generated water is not removed from the system, and the waste is only a small amount of waste water. Since it is excellent in productivity, it can be used without being limited to the structure of the resulting ester compound, and is useful.

In the formula, R ^{1 to} R ⁵ , R ^{7 to} R ¹⁰ and R ^{12 to} R ²⁶ are each independently a hydrogen atom, a halogen atom, a monovalent acyl group having 1 to 20 carbon atoms, or 1 having 1 to 20 carbon atoms. A monovalent alkyl group having 1 to 20 carbon atoms, a monovalent alkylthio group having 1 to 20 carbon atoms, a monovalent alkylsilyl group having 1 to 20 carbon atoms, a nitro group, a carboxyl group, a hydroxyl group, An atom or a substituent selected from the group consisting of a mercapto group, an amino group, a cyano group, a phenyl group and a naphthyl group, wherein R ⁶ , R ¹¹ and R ²⁷ are a divalent alkylene group having 1 to 20 carbon atoms; / Or a divalent alkylene oxide group having 1 to 30 carbon atoms, wherein (X ¹ ) ⁻ to (X ³ ) ⁻ each represents an anion.

In the general formulas (1) to (3), examples of the anion represented by (X ¹ ) ⁻ to (X ³ ) ⁻ include a halide anion, a hydroxide anion, a thiocyanate anion, and a carbon number of 1 to 4. Dialkyldithiocarbamate anion, carbonate anion, bicarbonate anion, sulfate anion, hydrogen sulfate anion, aliphatic or aromatic carboxy anion optionally substituted with halogen (benzoate anion, trifluoroacetate anion, perfluoroalkylacetate anion) , And phenylglyoxylate anions), aliphatic or aromatic sulfoxy anions optionally substituted with halogen (such as trifluoromethanesulfonate anion and p-toluenesulfonate anion), hexafluoroantimonate anions (SbF ₆₎ ^-), phosphine anion [hexafluoride phosphine A On (PF ₆ ^-) and trifluoride tris (perfluoroethyl) phosphine anion _{(PF 3 (C 2 F 5} ) 3 -) , etc.] and borate anion (tetraphenyl borate and butyl triphenyl borate anion, etc.) and the like include Of these, from the viewpoint of catalytic ability, an aliphatic or aromatic sulfoxy anion optionally substituted with halogen and / or an aliphatic or aromatic carboxy anion optionally substituted with halogen are preferable, and halogen An aliphatic or aromatic sulfoxy anion which may be substituted with is more preferred.

Claims (6)

  Production of an ester compound in which dehydration condensation reaction of an organic acid (C) and a compound having a hydroxyl group in the molecule (D) is performed in carbon dioxide (B) in a supercritical state in the presence of Bronsted acid ionic liquid (A). Method.   The method for producing an ester compound according to claim 1, wherein the organic acid (C) is a carboxylic acid. The method for producing an ester compound according to claim 1 or 2, wherein the Bronsted acid ionic liquid (A) is one or more compounds represented by the following general formulas (1) to (3).

[Wherein R ^{1 to} R ⁵ , R ^{7 to} R ¹⁰ and R ^{12 to} R ²⁶ are each independently a hydrogen atom, a halogen atom, a monovalent acyl group having 1 to 20 carbon atoms, or a group having 1 to 20 carbon atoms. Monovalent alkyl group, monovalent alkoxy group having 1 to 20 carbon atoms, monovalent alkylthio group having 1 to 20 carbon atoms, monovalent alkylsilyl group having 1 to 20 carbon atoms, nitro group, carboxyl group, hydroxyl group , An atom or a substituent selected from the group consisting of a mercapto group, an amino group, a cyano group, a phenyl group and a naphthyl group, wherein R ⁶ , R ¹¹ and R ²⁷ are a divalent alkylene group having 1 to 20 carbon atoms. And / or a divalent alkylene oxide group having 1 to 30 carbon atoms, wherein (X1) ⁻ to (X3) ⁻ each represents an anion. ] The method for producing an ester compound according to claim 3, wherein R ^{1 to} R ⁵ in the general formula (1) are hydrogen atoms, and R ⁶ is an alkylene group having 3 or 4 carbon atoms. In the general formula (2), R ⁷ is a hydrogen atom or a methyl group, R ⁸ is an alkyl group having 1 to 4 carbon atoms, R ⁹ and R ¹⁰ are hydrogen atoms, and R ¹¹ is 3 or 3 carbon atoms. 4. The method for producing an ester compound according to claim 3, which is an alkylene group of 4. The method for producing an ester compound according to claim 3, wherein R ^{12 to} R ²⁶ in the general formula (3) are hydrogen atoms, and R ²⁷ is an alkylene group having 3 or 4 carbon atoms.