JP4040641B2 - Method for producing ester compound - Google Patents

Description

  The present invention relates to a method for producing an ester compound and a novel ester compound.

Polyalkylene glycol monoalkyl ether esters of dibasic acids are useful compounds as plasticizers for biodegradable resins and elastomers, and their application as antibacterial and antifungal agents are also known. As a method for producing these compounds, a dibasic acid and a polyalkylene glycol monoalkyl ether are reacted by azeotropic dehydration using a solvent such as toluene with para-toluenesulfonic acid or tetrabutyl titanate as a catalyst, followed by washing with alkaline water. Then, a method for removing the solvent (Patent Document 1), a similar method using dibasic acid anhydride instead of dibasic acid, dibasic acid methyl ester and polyethylene glycol monoalkyl ether as dibutyl tin oxide as a catalyst After the reaction, a method of removing unreacted polyethylene glycol monoalkyl ether by adding calcium oxide and activated carbon, reacting dibasic acid or dibasic acid methyl ester and polyethylene glycol monoalkyl ether with sulfuric acid catalyst under normal pressure And then add calcium hydroxide to unreact A method of removing polyethylene glycol monoalkyl ether, or a method of reacting dibasic acid and polyethylene glycol monoalkyl ether at a high temperature of 260 ° C. or higher without catalyst and removing unreacted polyethylene glycol monoalkyl ether by distillation (Patent Document) 2) etc. are known so far.
JP 2003-292474 A Japanese Patent Laid-Open No. 53-10645

  In the esterification of a compound containing an oxyalkylene group such as a polyalkylene glycol monoalkyl ether with an acid catalyst, side reactions based on the cleavage of an ether bond are generally likely to occur and coloring is also likely. The method using toluene or the like as an azeotropic dehydration solvent has a problem that a harmful solvent must be used, productivity per batch is low, and recovery of the solvent is necessary from the economical aspect. Further, in the method involving the water washing step, the loss is large unless the water solubility of the target product is low, and it is difficult to recover the unreacted portion when the polyalkylene glycol monoalkyl ether, which is usually used in excess, is water soluble. In the method of carrying out a normal pressure reaction using a metal catalyst or sulfuric acid without a solvent, a reaction temperature close to 220 ° C. is used, so that coloring is large. In addition, the method using a metal catalyst is not easy to separate and remove from the product, and if it remains, there is a problem that the electrical characteristics of the resin when blended as a plasticizer deteriorate, The method of reacting at a high temperature has a problem that the reaction is slow and the acid value of the product is high.

  The first problem of the present invention is that a dibasic acid polyalkylene glycol alkyl ether ester having a low acid value, high purity and good hue is obtained from a dibasic acid or a dibasic acid anhydride and a polyalkylene glycol monoalkyl ether. It is to provide a method for producing economically in a yield. The second object of the present invention is to provide a novel dibasic acid polyalkylene glycol alkyl ether ester useful as a biodegradable resin, an elastomer plasticizer, or a fungicide and fungicide.

  The present invention relates to an ester compound represented by the formula (1) (hereinafter referred to as an ester) in which a dibasic acid or an anhydride thereof and a polyalkylene glycol monoalkyl ether are reacted in the presence of an acid catalyst at a pressure of 0.1 to 40 kPa. A process for producing compound (1)) is provided.

R ¹ O— (X ¹ O) _n1 —OC—R ³ —COO— (X ² O) _n2 —R ² (1)
Wherein R ¹ and R ² are each independently a linear or branched alkyl group having 1 to 20 carbon atoms, and X ¹ and X ² are each independently a linear or branched alkylene having 2 to 4 carbon atoms. Group, n ₁ and n ₂ each independently represents an integer of 1 to 20, and R ³ represents a linear or branched alkylene group having 2 to 10 carbon atoms.)
The present invention also provides succinic acid bis [2- [2- (2-methoxyethoxy) ethoxy] ethyl] ester (hereinafter referred to as ester compound (1-1)) represented by the formula (1-1). .

MeO— (EO) ₃ —OC— (CH ₂ ) ₂ —COO— (EO) ₃ —Me (1-1)
(In the formula, Me represents a methyl group, and EO represents an oxyethylene group.)

  By the production method of the present invention, it is possible to economically produce a dibasic acid polyalkylene glycol alkyl ether ester having a low acid value, high purity and good hue. In addition, according to the present invention, bis [2- [2- (2-methoxyethoxy) ethoxy] ethyl] ester succinate, which is a novel compound useful as a plasticizer for biodegradable resins and elastomers, or a fungicide and fungicide, is obtained. Can be provided.

[Method for producing ester compound]
The present invention is a method for producing an ester compound (1) by reacting a dibasic acid or an anhydride thereof with a polyalkylene glycol monoalkyl ether in the presence of an acid catalyst at a pressure of 0.1 to 40 kPa. .

In formula (1), R ¹ and R ² each independently represent a linear or branched alkyl group having 1 to 20 carbon atoms, preferably a linear or branched alkyl group having 1 to 4 carbon atoms. X ¹ and X ² each independently represent a linear or branched alkylene group having 2 to 4 carbon atoms. n ₁ and n ₂ each independently represents an integer of 1 to 20, preferably an integer of 2 to 4. R ³ represents a linear or branched alkylene group having 2 to 10 carbon atoms, preferably a linear or branched alkylene group having 2 to 4 carbon atoms.

  The dibasic acid or its anhydride used as a raw material for the production method of the present invention is a dibasic acid having 4 to 12 carbon atoms or its anhydride, and from the viewpoint of effectively bringing about the effects of the production method of the present invention, the formula ( The dibasic acid represented by 2) or an anhydride thereof is preferable.

HOOC- (CH ₂ ) _k -COOH (2)
(In the formula, k represents an integer of 2 to 4.)
Specific examples of the dibasic acid having 4 to 12 carbon atoms or anhydrides thereof include succinic acid, glutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, decanedic acid, and anhydrides thereof. Succinic acid and succinic anhydride are preferred.

  In the polyalkylene glycol monoalkyl ether used as a raw material for the production method of the present invention, the alkylene unit preferably has 2 to 4 carbon atoms, more preferably 2 carbon atoms. The number of oxyalkylene groups is preferably 1 to 20, more preferably 2 to 10, more preferably 2 to 4, more preferably 2 to 3 from the viewpoint of removing unreacted polyalkylene glycol monoalkyl ether after the reaction. Particularly preferred is 3 and most preferred. 1-20 are preferable, as for carbon number of an alkyl group, 1-6 are more preferable from a viewpoint which brings about the effect of the manufacturing method of this invention effectively, 1-4 are still more preferable, and 1-2 are especially preferable.

  Specific examples of preferred polyalkylene glycol monoalkyl ethers include diethylene glycol monomethyl ether, diethylene glycol monoethyl ether, diethylene glycol mono n-propyl ether, diethylene glycol mono i-propyl ether, diethylene glycol mono n-butyl ether, diethylene glycol mono i-butyl ether, triethylene Glycol monomethyl ether, triethylene glycol monoethyl ether, triethylene glycol mono n-propyl ether, triethylene glycol mono i-propyl ether, triethylene glycol mono n-butyl ether, triethylene glycol mono i-butyl ether, tetraethylene glycol monomethyl ether , Tetraethyleneglycol Monoethyl ether, tetraethylene glycol monobutyl n- propyl ether, tetraethylene glycol monobutyl i- propyl ether, tetraethylene glycol monobutyl n- butyl ether, etc. tetraethylene glycol monobutyl i- ether.

  As the acid catalyst used in the production method of the present invention, organic sulfonic acids such as methanesulfonic acid and paratoluenesulfonic acid are preferable, and paratoluenesulfonic acid is particularly preferable from the viewpoint of coloring resistance and few side reactions. The amount of the acid catalyst used is preferably 0.01 to 5% by weight, more preferably 0.03 to 3% by weight, based on the dibasic acid or its anhydride.

  In the production method of the present invention, the dibasic acid or its anhydride and the polyalkylene glycol monoalkyl ether are used in a molar ratio [polyalkylene glycol monoalkyl ether / dibasic acid or its basic acid, from the viewpoint of reaction efficiency and economy. [Anhydride] is preferably reacted at a ratio of 2 to 10, more preferably 2 to 5, and still more preferably 2 to 3.

  In the production method of the present invention, the pressure can be reacted under a reduced pressure of 0.1 to 40 kPa and varies depending on the boiling point of the raw material and the reaction temperature. By carrying out under such a reduced pressure, the reaction rate is fast, the acid value tends to decrease, and coloring can be suppressed. Although a solvent may be used, it is preferable to carry out the reaction without solvent from the viewpoint of productivity and economy. A small amount of inert gas such as nitrogen is preferably allowed to flow during the reaction in order to suppress coloring.

  In the production method of the present invention, the reaction temperature is preferably 90 to 180 ° C, more preferably 100 to 150 ° C, and still more preferably 110 to 140 ° C from the viewpoint of increasing the reaction rate and suppressing coloring and by-products. Although reaction time is based also on reaction temperature, 3 to 20 hours are preferable.

  The reaction solution obtained by the reaction is contacted with an acidic substance adsorbent at normal pressure or reduced pressure at 60 to 90 ° C. for 0.5 to 2 hours, and then filtered to remove the catalyst and other acidic components. Is preferred. Examples of the acidic substance adsorbent include Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.). The amount of the adsorbent is preferably 0.1 to 5% by weight with respect to the reaction mixture. Unreacted polyalkylene glycol monoalkyl ether is removed from the filtrate at 25 to 220 ° C., preferably 180 ° C. or less under normal pressure or reduced pressure, and after cooling, filtration is performed to obtain the desired ester compound (1).

[Ester compounds (1) and (1-1)]
In the ester compound (1) obtained by the production method of the present invention, R ¹ and R ² each independently represents a linear or branched alkyl group having 1 to 20 carbon atoms, but an alkyl group having 1 to 6 carbon atoms. Is preferable, an alkyl group having 1 to 4 carbon atoms is more preferable, an alkyl group having 1 to 2 carbon atoms is particularly preferable, and a methyl group is most preferable. X ¹ and X ² each independently represent a linear or branched alkylene group having 2 to 4 carbon atoms, preferably an ethylene group. n ₁ and n ₂ each independently represent an integer of 1 to 20, preferably 2 to 10, more preferably 2 to 4, still more preferably 2 to 3, and particularly preferably 3. R ³ represents a linear or branched alkylene group having 2 to 10 carbon atoms, preferably a linear alkylene group having 2 to 4 carbon atoms, and more preferably an ethylene group.

Among the ester compounds (1), R ¹ and R ² are methyl groups, X ¹ and X ² are ethylene groups, n ₁ and n ₂ are 3, and R ³ is an ethylene group (1-1) Is a novel compound. The ester compound (1-1) is useful as a biodegradable resin, an elastomer plasticizer, or a fungicide and fungicide, and is particularly useful as a biodegradable resin plasticizer.

Example 1
While charging 590 g of succinic acid, 2297 g of triethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonic acid monohydrate into a 3 L flask equipped with a stirrer, a thermometer, and a dehydrating tube, nitrogen (200 mL / min) was blown into the space. The mixture was reacted at 2.7-8 kPa and 120 ° C. for 11 hours under reduced pressure. The acid value of the reaction solution was 1.3 (KOH mg / g). 27 g of adsorbent Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) was added to the reaction solution, stirred at 80 ° C. and 3.1 kPa for 1 hour and pressure filtered, and then the liquid temperature / pressure 118 ° C./2.5 kPa- Triethylene glycol monomethyl ether was distilled off at 190 ° C./0.8 kPa, and after cooling to 80 ° C., the remaining liquid was filtered under pressure to obtain an ester compound (1-1) as a filtrate. The obtained ester compound (1-1) had an acid value of 0.4 (KOHmg / g), a saponification value of 276 (KOHmg / g), a hydroxyl value of 1 or less (KOHmg / g), and a hue of APHA60. Moreover, when the < ¹ > H-NMR spectrum was measured, the result shown in FIG. 1 was obtained.

Example 2
A 3 L flask equipped with a stirrer, thermometer and dehydration tube was charged with 500 g of succinic anhydride, 2463 g of triethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonic acid monohydrate, and nitrogen (500 mL / min) was blown into the space. The reaction was carried out at 4 to 10.7 kPa and 110 ° C. for 15 hours under reduced pressure. The acid value of the reaction solution was 1.6 (KOH mg / g). After adding 27 g of adsorbent Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) to the reaction solution and stirring and filtering at 80 ° C. and 2.7 kPa for 45 minutes, the solution temperature was 115 to 200 ° C. and the pressure was 0.03 kPa. Ethylene glycol monomethyl ether was distilled off, and after cooling to 80 ° C., the remaining liquid was filtered under reduced pressure to obtain an ester compound (1-1) as a filtrate. The obtained ester compound (1-1) had an acid value of 0.2 (KOHmg / g), a saponification value of 276 (KOHmg / g), a hydroxyl value of 1 or less (KOHmg / g), and a hue of APHA200.

Comparative Example 1
A 3 L flask equipped with a stirrer, thermometer and dehydrating tube was charged with 500 g of succinic anhydride, 2464 g of triethylene glycol monomethyl ether, and 9.5 g of paratoluenesulfonic acid monohydrate, and nitrogen (500 mL / min) was blown into the space. The reaction was carried out at 120 ° C. for 30 hours under normal pressure. The acid value of the reaction solution was 2.3 (KOH mg / g). After adding 27 g of adsorbent Kyoward 500SH (manufactured by Kyowa Chemical Industry Co., Ltd.) to the reaction solution and stirring and filtering at 80 ° C. and 2.7 kPa for 45 minutes, the solution temperature was 115 to 190 ° C. and the pressure was 0.03 kPa. Ethylene glycol monomethyl ether was distilled off, and after cooling to 80 ° C., the remaining liquid was filtered under reduced pressure to obtain an ester compound (1-1) as a filtrate. The obtained ester compound (1-1) had an acid value of 1.4 (KOH mg / g), a saponification value of 283 (KOH mg / g), a hydroxyl value of 5.4 (KOH mg / g), and a hue of APHA500.

Reference example 1
The ester compound (1-1) obtained in Example 1 was evaluated as a plasticizer of a biodegradable resin. Evaluation is performed by evaluating volatilization resistance, flexibility, transparency and bleed resistance by the following methods, and evaluation of volatilization resistance is performed by the ester compound (1-1) alone by the following method. Evaluation of transparency and bleed resistance was performed by measuring the poly (lactic acid) resin (LACEA H-400, manufactured by Mitsui Chemicals, Inc.) 100 obtained by vacuum drying the ester compound (1-1) at 50 ° C. for 24 hours. It is added to 15 parts by weight with respect to parts by weight, kneaded for 10 minutes with a 180 ° C. kneader (Toyo Seiki Co., Ltd., “Lab Plast Mill”), and thickened with a 190 ° C. press molding machine. A 0.5 mm test piece was prepared, and the obtained test piece was subjected to the following method.

  Further, as a reference product, bis [2- (2-methoxyethoxy) ethyl] ester adipate, which has been conventionally known as a plasticizer for polylactic acid ester, was similarly evaluated. These results are shown in Table 1.

<Evaluation method for volatility>
Using a thermogravimetric analyzer, the plasticizer was heated from room temperature to 330 ° C. (5 ° C./min) in a nitrogen atmosphere, and the temperature at which the weight was reduced by 10% was measured. The higher the temperature, the better the volatility resistance.

<Flexibility evaluation method>
The test piece was punched with a No. 3 dumbbell, left in a temperature-controlled room at a temperature of 23 ° C. and a humidity of 50% RH for 24 hours, a tensile test was performed at a tensile speed of 50 mm / min, and the flexibility was expressed in terms of elastic modulus and breaking elongation%. . The lower the elastic modulus value, the higher the breaking elongation% value, the higher the flexibility.

<Transparency evaluation method>
The haze value of the test piece was measured using an integrating sphere light transmittance measuring device (haze meter) defined in JIS-K7105. Smaller numbers indicate better transparency.

<Bleed resistance (with or without bleed)>
A test piece (length 100 mm × width 100 mm × thickness 0.5 mm) was left in a thermostatic chamber at 70 ° C. for 72 hours, and the presence or absence of a plasticizer bleed on the surface was observed with the naked eye. Evaluation of bleed resistance is an indispensable item for evaluating the performance of a plasticizer because not only the surface quality of the resin but also the flexibility of the resin situation is impaired by bleed.

1 is a ¹ H-NMR spectrum of an ester compound (1-1) obtained in Example 1.

Claims (3)

The dibasic acid represented by the formula (2) or an anhydride thereof is reacted with a polyalkylene glycol monoalkyl ether in the presence of an acid catalyst at a pressure of 0.1 to 40 kPa in the absence of a solvent , the formula (1) The manufacturing method of the ester compound represented by these.
R ¹ O— (X ¹ O) _n1 —OC—R ³ —COO— (X ² O) _n2 —R ² (1)
Wherein R ¹ and R ² are each independently a linear or branched alkyl group having 1 to 4 carbon atoms, and X ¹ and X ² are each independently a linear or branched alkylene having 2 to 4 carbon atoms. Group, n ₁ and n ₂ each independently represents an integer of 1 to 20, and R ³ represents a linear alkylene group having 2 to 4 carbon atoms.)
HOOC- (CH ₂ ) _k -COOH (2)
(In the formula, k represents an integer of 2 to 4.) Process of claim 1 acid catalyst is an organic sulfonic acid. Succinic acid bis [2- [2- (2-methoxyethoxy) ethoxy] ethyl] ester represented by the formula (1-1).
MeO— (EO) ₃ —OC— (CH ₂ ) ₂ —COO— (EO) ₃ —Me (1-1)
(In the formula, Me represents a methyl group, and EO represents an oxyethylene group.)

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