JP2010202541A - Method for producing ethylene glycol (meth)acrylate - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new method for producing ethylene glycol (meth)acrylate, by which the ethylene glycol (meth)acrylate can be produced in a short reaction time and in high selectivity, instead of a conventional method for producing the ethylene glycol (meth)acrylate by the ester exchange reaction of ethylene glycol with (meth)acrylate, wherein the ethylene glycol (meth)acrylate includes ethylene glycol diacrylate, ethylene glycol-1-acrylate-2-methacrylate, ethylene glycol-1-methacrylate-2-acrylate and ethylene glycol dimethacrylate. <P>SOLUTION: This method for producing the ethylene glycol (meth)acrylate is characterized by subjecting methyl (meth)acrylate and hydroxyethyl (meth)acrylate, instead of ethylene glycol and (meth)acrylate of a conventional method as starting raw materials, to an ester exchange reaction in the presence of a tin-based catalyst and a polymerization inhibitor. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method for producing ethylene glycol (meth) acrylate, and more particularly to a method for producing ethylene glycol (meth) acrylate by transesterification of methyl (meth) acrylate and hydroxyethyl (meth) acrylate. (Meth) acrylate means acrylate and methacrylate.

  Ethylene glycol (meth) acrylate is widely used in various industrial fields such as adhesives and paints. And as the manufacturing method, the direct esterification method, the transesterification method, etc. are known.

  As an example of producing ethylene glycol (meth) acrylate by a transesterification method, for example, in Patent Document 1 (Japanese Patent Laid-Open No. 7-188108), an organic material subjected to heat treatment at 50 to 150 ° C. in an organic medium as a catalyst. A method of producing a corresponding di (meth) acrylate by transesterifying a divalent alcohol compound and an unsaturated lower carboxylic acid ester in the presence of this catalyst using a tin compound has been proposed.

  Patent Document 2 (Republished Patent WO2004 / 069783) discloses that methanol produced as a by-product under reflux conditions is removed from the system as an azeotrope with methyl methacrylate, while methyl methacrylate and alcohol or phenols. A process for producing the corresponding methacrylates by carrying out a transesterification reaction is described.

JP 7-188108 A Republished patent WO2004 / 069783

  All of the conventional methods for producing ethylene glycol (meth) acrylate by the transesterification method use, as starting materials, ethylene glycol and usually 3 or more moles of (meth) acrylate per mole of ethylene glycol, and these are organic Transesterification is carried out by heating in the presence of a metal compound catalyst.

  However, in the case of the above conventional method, it was not satisfactory from the viewpoint of production on an industrial scale. That is, there is a problem that the reactivity is low, it takes time to complete the reaction, and the selectivity of the target ethylene glycol (meth) acrylate is low, resulting in a low yield.

  The object of the present invention is to solve the problems of the conventional methods described above and to produce ethylene glycol (meth) acrylate more advantageously industrially, that is, a novel ethylene glycol capable of shortening the reaction time and improving the selectivity. An object of the present invention is to provide a method for producing (meth) acrylate.

  According to the study by the present inventors, methyl (meth) acrylate and hydroxyethyl (meth) acrylate are used as starting materials instead of ethylene glycol and (meth) acrylate of the conventional method, and these are subjected to a transesterification reaction. It was found that the above-mentioned purpose can be achieved. The present invention has been completed based on such findings.

  That is, this invention is a manufacturing method of ethylene glycol (meth) acrylate characterized by carrying out transesterification of methyl (meth) acrylate and hydroxyethyl (meth) acrylate.

  According to the method of the present invention, the transesterification reaction is highly reactive and the reaction time is shortened. Moreover, the selectivity of ethylene glycol (meth) acrylate is high, and ethylene glycol (meth) acrylate can be produced in a high yield.

  The ethylene glycol (meth) acrylate obtained by transesterification of methyl (meth) acrylate and hydroxyethyl (meth) acrylate of the present invention includes ethylene glycol diacrylate, methyl acrylate and hydroxy from methyl acrylate and hydroxyethyl acrylate. Ethylene glycol-1-acrylate-2-methacrylate from ethyl methacrylate, ethylene glycol-1-acrylate-2-methacrylate from methyl methacrylate and hydroxyethyl acrylate, and ethylene glycol dimethacrylate from methyl methacrylate and hydroxyethyl methacrylate Is included.

  There are no particular restrictions on the catalyst, polymerization inhibitor, etc. used in the transesterification reaction, which are generally used in transesterification reactions. For example, ethylene glycol (by the transesterification reaction between ethylene glycol and (meth) acrylates in the conventional method) It can carry out using a catalyst, a polymerization inhibitor, etc. which are generally used when manufacturing a (meth) acrylate.

  Examples of the catalyst include organic tin compounds, specifically stannous formate, stannous acetate, stannous propionate, stannous butyrate, stannous valerate, stannous caproate, caprylic acid. Stannous, stannous caprate, stannous laurate, stannous benzoate, stannous maleate, stannous fumarate, stannous methoxy, stannous ethoxy, stannous propoxy, butoxy Stannous compounds such as stannous, pentaoxystannic, hexaoxystannic, phenoxystannic, benzyloxystannic, dimethyl stannic oxide, dibutyl stannic oxide, dihexyl stannic oxide, Dioctyl stannic oxide, tributyl stannic hydroxide, triooctyl stannic hydroxide, dibutyl stannic chloride, dioctyl stannic chloride, trioctyl stannic chloride , Dibutyltin acetate, dioctyltin acetate, dibutyltin butyrate, dioctyltin butyrate, dibutyltin laurate, dioctyltin laurate, dibutyltin benzoate, dioctyltin benzoate, dibutyltin salicylate, dioctyltin maleate, methoxydibutyltin, methoxydioctyltin, ethoxydibutyltin Stannic compounds such as propoxydioctyltin, butoxydibutyltin, butoxydioctyltin, phenoxydibutyltin, and benzyloxydioctyltin can be used. These can be used alone or in combination of two or more. Of these, dibutyl stannic oxide (dibutyltin oxide (DBTO)) is preferably used.

  The catalyst may be used in an amount sufficient to achieve the esterification reaction, and is usually 0.001 to 1 mol, preferably 0.001 to 0.1 mol per mol of hydroxyethyl (meth) acrylate. Is a mole.

  The polymerization inhibitor may be any compound as long as it has a polymerization-inhibiting effect such as methyl (meth) acrylate, and examples thereof include phenolic compounds such as hydroquinone and paramethoxyphenol, phenothiazine, hydroquinone, N-phenyl-N′-. Amine compounds such as isopropylparaphenylenediamine, N, N′-di-2-naphthylparaphenylenediamine, N-phenyl-N ′-(1,3-dimethylbutyl) paraphenylenediamine, 4-hydroxy-2,2 , 6,6-tetramethylpiperidine-N-oxyl, 4-benzoyloxy-2,2,6,6-tetramethylpiperidine-N-oxyl, 4-acetylamino-2,2,6,6-tetramethylpiperidine An oxyl compound such as -N-oxyl can be used. These can be used alone or in combination of two or more. Of these, 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl (4H-TEMPO) is preferably used.

  The amount of the polymerization inhibitor used is appropriately determined within a range in which the polymerization prevention effect is obtained, but is usually 0.00001 to 1 mol, preferably 0.00001 to 0.1 mol per mol of hydroxyethyl (meth) acrylate. is there.

  The transesterification reaction between methyl (meth) acrylate and hydroxyethyl (meth) acrylate according to the present invention is an equilibrium reaction and can be carried out in the same manner as the transesterification reaction between ethylene glycol and (meth) acrylate in the conventional method. it can. For example, using a reaction apparatus equipped with a distillation column, a transesterification reaction proceeds under reflux conditions while extracting by-product methanol as an azeotrope with methyl (meth) acrylate from the top of the distillation column outside the system (batch). Formula reactive distillation). If methanol is contained in the reflux liquid returning from the distillation column to the reaction kettle, the reaction rate decreases. Therefore, it is desirable to appropriately determine the number of distillation column stages, the reflux ratio, and the like so as not to affect the reactivity.

  The distillation column is not particularly specified, and a distillation column generally used for this type of transesterification reaction can be used.

  Since the reaction temperature is reactive distillation, it is determined by the methyl (meth) acrylate concentration and methanol concentration contained in the reaction solution. For example, at normal pressure, it is 80 to 180 ° C, preferably 100 to 150 ° C. If it is less than 80 ° C., the methyl (meth) acrylate is present in a large excess, resulting in low productivity, and it is not economical because it is necessary to remove the excessive methyl (meth) acrylate after the reaction. On the other hand, if it exceeds 180 ° C., polymerization tends to occur, which is not preferable.

  Regarding the ratio of methyl (meth) acrylate and hydroxyethyl (meth) acrylate necessary for the transesterification reaction, for example, methyl (meth) acrylate is 0.8 to 1.2 mol per mol of hydroxyethyl (meth) acrylate. , Preferably it should just exist in the ratio of 1-1.1 mol.

  In addition, as mentioned above, it is preferable that methanol produced as a by-product in the method of the present invention is extracted from the distillation tower as an azeotropic mixture with methyl (meth) acrylate, and methyl (meth) acrylate as this azeotropic solvent is used. It is preferable to charge the reaction system in advance. The amount of methyl (meth) acrylate at this time is not particularly limited, but is 0.1 to 1, preferably 0.1 to 0.5 mol per mol of hydroxyethyl (meth) acrylate.

  Also, as the amount of methyl (meth) acrylate in the reaction system decreases with the progress of azeotropic distillation, the required amount of methyl (meth) acrylate is added to the reaction system to compensate for this decrease in methyl (meth) acrylate. It is desirable to supply. The supply amount of (meth) acrylate can be appropriately determined in consideration of the amount of distillate extracted and the reaction time depending on the distillation conditions.

  Catalysts and polymerization inhibitors are generally used by dissolving them in the starting materials, methyl (meth) acrylate and hydroxyethyl (meth) acrylate, but in an organic solvent, methylation is carried out in the presence of the catalyst and polymerization inhibitor. You may perform transesterification with (meth) acrylate and hydroxyethyl (meth) acrylate. As this organic solvent, benzene, hexane, toluene and the like are used.

Hereinafter, the present invention will be described more specifically with reference to examples.
Example 1
As a reaction apparatus, a 2 L (liter) four-necked flask equipped with an old show distillation tower having 20 stages of weirs and a tower inner diameter of 25 mm was used. This apparatus is configured such that the steam that has been heated to the distillation column is cooled by a condenser and returned to the uppermost stage of the distillation column by a reflux line.

  Hydroxyethyl methacrylate (HEMA) having a purity of 99.9% by mass of methyl methacrylate (MMA) (582 g, 5.8 mol) and a purity of 97.5% by mass (containing 2.3% by mass of diethylene glycol monomethacrylate (DEGMMA)) in the flask. 540 g (4.2 mol) (HEMA: 4.1 mol, DEGMMA: 0.1 mol), 5.4 g of dibutyltin oxide (DBTO) as a catalyst, and 4-hydroxy-2,2,6, as a polymerization inhibitor A solution in which 0.5 g of 6-tetramethylpiperidine-N-oxyl (4H-TEMPO) is charged and 4H-TEMPO is dissolved in MMA from the top of the distillation column to a concentration of 0.2% by mass is continuously added. Feeding at 2 ml / hr and transesterification at normal pressure while introducing air into the reaction solution at 3 ml / min I went. The reaction solution was heated by immersing the flask in an oil bath. The reaction temperature was maintained at 110 to 140 ° C. for reaction, and the reaction solution in the flask was sampled over time and analyzed by gas chromatography to measure unreacted HEMA.

  At the beginning of the reaction, total reflux was performed, and the extraction of the methanol / MMA azeotrope out of the system was started after the temperature at the top of the distillation column reached 65 ° C. The extraction rate was 50 g / hr, and MMA was supplied at 50 g / hr so as to compensate for the reaction solution loss in the flask. Thereafter, until the reaction conversion rate of HEMA reaches 95% or more, the amount of steam rising to the distillation column is controlled by setting the oil bath temperature to + 15 ° C. with respect to the reaction liquid temperature in the flask, and the reflux ratio is 2 to 10%. The reaction was conducted in the range of.

  After 12 hours from the start of extraction of the methanol / MMA azeotrope to the outside of the system, the unreacted HEMA concentration in the reaction solution became 2.5% by mass or less (conversion rate of HEMA reaction was 95% or more). Therefore, the reaction was stopped by cooling the reaction solution.

  When 1150 g of the obtained reaction solution was analyzed by gas chromatography, the results were as follows. Ethylene glycol dimethacrylate (EGDMA) mass 69%, MMA mass 26%, HEMA mass 2%, diethylene glycol dimethacrylate (DEGDMA) 1 mass%, and other impurities including catalyst components in total 1 mass%.

Therefore, the EGDMA selectivity (raw material HEMA standard) was 97%, and the DEGDMA selectivity (raw material HEMA standard) was 2%. Further, since the selectivity from DEGMMA to DEGDMA contained in the raw material HEMA is 2%, the actual EGDMA selectivity was 99% or more.
(Comparative Example 1)
As a reaction apparatus, a 2 L glass four-necked flask equipped with a Dean-Stark dehydration apparatus, a condenser and a vacuum apparatus and equipped with an air introduction tube, a thermometer and a stirrer was charged with 200 g of ethylene glycol (EG) having a purity of 99.9% by mass. (3.2 mol), 555 g (6.5 mol) of methacrylic acid (MAA) having a purity of 99.9% by mass, 22 g of sulfuric acid, 3.5 g of hydroquinone, and 260 g of toluene as a solvent were charged. Next, the inside of the flask was stirred while air was blown into the flask, and the pressure was reduced to 730 hPa with a vacuum apparatus to perform the esterification reaction directly.

  The temperature of the reaction solution was increased by immersing the flask in an oil bath. To control the amount of toluene vapor rising to the distillation column, the reaction temperature was maintained at 100 to 130 ° C. by setting the oil bath temperature to + 30 ° C. with respect to the reaction liquid temperature in the flask. At a reaction temperature of about 100 ° C., toluene began to reflux, and the amount of produced water distilled into the dehydrator was confirmed.

  In 4 hours from the start of the reaction, 105 mL of generated water flowed out, but since the distillation of the generated water was not observed for 1 hour, the reaction was terminated, and the reaction solution was immediately cooled to room temperature (EG had a reaction conversion rate of 100%). The amount of produced water is 116 g (6.5 mol)).

When 930 g of the obtained reaction liquid was analyzed by gas chromatography, EG was 0.1% by mass or less (reaction conversion rate: 100%), MAA was 11% by mass, and other impurities including diethylene glycol dimethacrylate as impurities were 11% by mass in total, The ethylene glycol dimethacrylate (EGDMA) was 43% by mass, and the EGMA selectivity based on EG was 63%.
(Comparative Example 2)
In Example 1, 250 g (4.0 mol) of EG having a purity of 99.9% by mass was used instead of HEMA as a raw material, and the amount of MMA having a purity of 99.9% by mass was adjusted to 872 g (8.7 mol). The same reaction operation as in Example 1 was performed except that the change was made. In addition, this comparative example 2 is based on the comparative example 2 of patent document 1 (Unexamined-Japanese-Patent No. 7-188108).

  Since the temperature of the uppermost stage of the distillation column only decreased to about 95 ° C., the total reflux was set to 1 hour, and extraction of the methanol / MMA azeotrope was started out of the system.

  Since the EG reaction conversion rate of the reaction solution was 4% (unreacted EG concentration was 21%) even after 5 hours had passed since the start of the extraction of the methanol / MMA azeotrope to the outside of the system, the reaction solution was As a result of confirmation, the reaction solution was separated into two layers of EG and MMA. Some polymer was also generated.

Claims (2)

A process for producing ethylene glycol (meth) acrylate, comprising transesterifying methyl (meth) acrylate and hydroxyethyl (meth) acrylate. The ethylene glycol according to claim 1, wherein the transesterification reaction is carried out using dibutyl stannic oxide as a catalyst and 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl as a polymerization inhibitor. A method for producing (meth) acrylate.