JP2002088019A - Method for producing (meth)acrylic acid ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a (meth)acrylic acid ester, capable of obtaining a (meth)acrylic acid ester in an excellent reaction yield. SOLUTION: This method for producing a (meth)acrylic acid ester using an alcohol and an acid as raw materials and a cation exchange resin as a catalyst is characterized in that a dehydration process for removing water impregnate into the cation exchange resin by using at least one selected from the alcohol, the acid and a formed ester a solvent for dehydration is carried out and successively an esterification reaction process is performed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a (meth) acrylate ester using an alcohol and an acid as raw materials and using a cation exchange resin as a catalyst.

[0002]

2. Description of the Related Art Conventionally, ion exchange resins which have been used as catalysts in the production of (meth) acrylic acid esters from alcohols and acids as raw materials are usually marketed in a wet state with water. Often. When the ion exchange resin is used for the reaction, generally, in order to prevent damage to the resin, water is previously charged into the reaction vessel, and after the resin is charged, the water is discharged out of the vessel. Then, the ion exchange resin is filled in the reaction vessel. However, since the esterification reaction is an equilibrium reaction, if water is present in the reaction system, the conversion is low and the reaction does not easily proceed. Therefore, if the amount of water contained in the ion exchange resin used as a catalyst in the esterification reaction is large, there arises a problem that the reaction yield decreases. Therefore, it is desired to reduce the water content of the ion exchange resin as much as possible before using it in the esterification reaction.

[0003]

Accordingly, an object of the present invention is to provide a method for producing a (meth) acrylic ester which can obtain a (meth) acrylic ester with an excellent reaction yield. Is to do.

[0004]

Means for Solving the Problems The present inventor has made intensive studies to solve the above-mentioned problems. As a result, prior to the esterification reaction step, during the production of the (meth) acrylic acid ester, using either the alcohol or acid that is the raw material of the esterification reaction or the ester generated by the esterification reaction, It has been found that the yield of the esterification reaction can be significantly improved by performing a dehydration step of removing water impregnated in the ion exchange resin, and the present invention has been completed. That is, the method for producing a (meth) acrylate according to the present invention is a method for producing a (meth) acrylate using an alcohol and an acid as raw materials and using a cation exchange resin as a catalyst, Water that is impregnated in the resin is subjected to an esterification reaction step following the dehydration step of removing at least one selected from the alcohol, the acid, and the generated ester using a dehydration solvent. I do.

[0005]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below in detail. In the method for producing a (meth) acrylate according to the present invention, it is important to perform a dehydration step of removing water impregnated in a cation exchange resin used as a catalyst, prior to the esterification reaction step. By sufficiently reducing the water content of the cation exchange resin in advance in the dehydration step, the yield in the subsequent esterification reaction can be improved. In the present invention, the dehydration step comprises converting at least one selected from alcohols, acids, and esters formed in the esterification reaction, which are raw materials for the esterification reaction, to a cation exchange resin using a solvent for dehydration. This is a step of removing impregnated water. By using a raw material for the esterification reaction or an ester formed in the esterification reaction as the dehydration solvent, even when the dehydration solvent remains in the ion-exchange resin after dehydration,
The reaction yield can be efficiently improved without hindering the esterification reaction.

In the dehydration step, the method of removing water impregnated in the cation exchange resin is not particularly limited except for using the dehydration solvent described above. For example, the ion exchange resin is washed with the solvent. And a method of adding the above-mentioned solvent to the ion-exchange resin and distilling it by distillation. In the case of the method of washing the cation exchange resin with the solvent, more specifically, for example, when the method is performed in a fixed bed reactor, after filling the reaction container with the ion exchange resin, the solvent for dehydration is continuously added. The water in the ion-exchange resin may be removed by passing the resin charged into the reaction vessel between the filled resins, and preferably, the dehydration solvent is heated in advance, or the reaction vessel Is heated using a heat source such as steam.
In this case, the heating temperature is preferably about 30 to 120 ° C. When the reaction is carried out in a fluidized bed reactor, the ion exchange resin and the dehydrating solvent are charged into the reaction vessel and stirred for a certain period of time, and then only the liquid in the vessel is extracted and a new dehydrating solvent is added again. The water is removed from the ion-exchange resin by repeatedly charging the same solvent, or by continuously charging the dehydration solvent into the reaction vessel while keeping the liquid volume in the reaction vessel constant. Good. As a method for washing the ion-exchange resin with a solvent, the method using the above-described fixed bed reactor is preferable. The washing is preferably performed until the water concentration in the waste liquid after washing becomes 10% by weight or less, preferably 5% by weight or less.

In the case of the above-mentioned method of adding a solvent to the cation exchange resin and distilling the cation exchange resin, the solvent and the ion exchange resin are charged into a reaction vessel to form a slurry, and the mixture is heated while stirring. Then, the water in the ion exchange resin may be removed by distillation. In particular, when the dehydrating solvent used forms an azeotropic composition with water, azeotropic dehydration is preferred. The heating temperature during the distillation, the heating time, etc. may be appropriately set according to the boiling point of the solvent used, etc., and are not particularly limited, but preferably, the heating temperature is about 30 to 120 ° C., and the heating time is The time is preferably about 2 to 24 hours. The method of distilling and dehydrating the ion-exchange resin may be performed by any apparatus as long as it is a fluidized bed reaction type, and is particularly preferably performed by a fluidized bed reactor equipped with a distillation column. Further, the distillation is carried out until the water content calculated from the water content of the ion exchange resin before dehydration and its filling amount is distilled off as an aqueous phase, or the pressure conditions are adjusted according to the dehydrating solvent used. Is determined, there is a correlation between the water concentration in the pressure vessel and the temperature in the reactor. Therefore, it is desirable to carry out until the water concentration reaches a temperature at which the target concentration (normally 5% by weight or less) is reached. .

In the present invention, the dehydration step is preferably performed under reduced pressure. In particular, when the dehydration step is performed by a method in which a dehydrating solvent is added to an ion exchange resin and distillation is performed, dehydration can be promoted by distillation under reduced pressure, which is effective. In particular, when the end point temperature of the above-mentioned distillation exceeds 120 ° C. during the dehydration by distillation, it is more preferable to perform the reaction under reduced pressure. Although the degree of decompression when depressurizing is not particularly limited, it is 30 to 700.
hPa, more preferably 50 to 300 hPa. In the present invention, it is preferable that the solvent for dehydration is recovered from the waste liquid containing water and the solvent for dehydration generated in the dehydration step and reused in the dehydration step and / or the esterification reaction step. Specifically, in the case of the method of washing the ion-exchange resin with the solvent, the wastewater after washing may be distilled to separate the dehydration solvent contained in the wastewater from water, and the solvent may be ionized. In the case of distillation in addition to the exchange resin, after the generated vapor is condensed in a condenser, it is separated into an oil phase and an aqueous phase, and the oil phase is returned to the reaction vessel as a solvent for dehydration. Good. Further, the solvent for dehydration dissolved in the aqueous phase may be separated and recovered by a separate operation such as distillation, and reused in the dehydration step and / or the esterification reaction step. It is preferable that the operation of distilling, condensing, and separating the waste liquid for reuse is performed at the same time as the dehydration step, and is reused as needed.

In the dehydration step, the ratio of the cation exchange resin to the dehydration solvent is 1 to 30 times the volume (volume) of the cation exchange resin in a water-containing state. More preferably, it is used in an amount of 5 to 20 times (volume). When the amount of the solvent for dehydration is more than 30 times (volume), the dehydration time becomes longer and it is economically disadvantageous. On the other hand, when the amount is less than 1 time (volume), the dehydration efficiency decreases, and consequently esterification. Because the reaction yield decreases,
Not preferred. In the dehydration step, the dehydration is preferably performed until the water concentration in the reaction vessel filled with the ion exchange resin becomes 5% by weight or less. When the water concentration in the reaction vessel is within the above range, the yield can be sufficiently improved without inhibiting the esterification reaction. The moisture concentration can be measured, for example, by the method described in Examples below.

In the method for producing a (meth) acrylate according to the present invention, an esterification reaction step is performed following the dehydration step. In the esterification reaction step, an alcohol and an acid are used as raw materials, and a cation exchange resin is used as a catalyst. Acrylic acid or methacrylic acid is mentioned as an acid which is a raw material of the esterification reaction. These may be used alone or in combination of two. The alcohol which is a raw material of the esterification reaction is not particularly limited, and includes, for example, a saturated or unsaturated aliphatic alcohol having 1 to 12 carbon atoms, an alicyclic alcohol having 3 to 10 carbon atoms, Number 6
To 10 aromatic alcohols and the like. In particular, an aliphatic or alicyclic alcohol having 1 to 12 carbon atoms is preferably used. Representative examples include methanol, ethanol, propanol, isopropanol, n-butanol, isobutanol, sec-butanol, t-butanol, 1-pentanol, 2-pentanol, 3-pentanol, cyclopentanol, Hexanol, 2
-Hexanol, 3-hexanol, cyclohexanol, 1-heptanol, 2-heptanol, 3-heptanol, 1-octanol, isooctanol, 2-ethylhexanol, isononyl alcohol, lauryl alcohol and the like. These may be used alone or in combination of two or more.

The ion exchange resin which can be used in the present invention is not limited by the resin structure such as the resin structure and the degree of crosslinking, as long as it is a cation exchange resin.
For example, a porous or gel-type strongly acidic cation exchange resin is preferably used. Representative examples of the porous type strongly acidic cation exchange resin include MSC-1 (manufactured by Dow), PK-208, PK-212, PK-216 and P-216.
K-220, PK-228 (all manufactured by Mitsubishi Chemical Corporation), Amberlyst-16, IR-116, IR-118, I
R-122, C-26, C-26TR, C-264, C
-265 (Rome and Haas), SP
C-108, SPC-112 (all manufactured by Bayer AG),
KC-470 (manufactured by Sumitomo Chemical Co., Ltd.) and the like. Also,
Representative examples of the gel type strongly acidic cation exchange resin include HCR-S, HCR-W2, HGR-W2 (above,
Dow), SK-1B, SK-106, SK-110
(Mitsubishi Chemical Corporation), Duolite C20H, C2
55LFH (from Rohm and Haas), K
1221, K1431 (all manufactured by Bayer AG) and the like. Of course, the invention is not limited to these, and a weakly acidic cation exchange resin or the like can be used. These cation exchange resins may be used alone or in combination of two or more. In the present invention, the specific method of the esterification reaction step and various conditions such as the reaction temperature may be appropriately set, and are not particularly limited. Preferably, in the esterification reaction step, after the dehydration step is completed, the raw material acid and alcohol are charged in a state where the dehydration solvent remains in the reaction vessel to start the esterification reaction.

In the present invention, it is preferable that the dehydration step is performed using a reaction vessel of a reactor for performing the esterification reaction step. As described above, by performing the dehydration step in the reactor of the apparatus used in the esterification reaction step, both steps can be performed continuously, and the (meth)
Acrylic esters can be produced.

[0013]

EXAMPLES Examples and comparative examples according to the present invention will be described below, but the present invention is not limited by these examples. The measurement of the water concentration and the conversion of acrylic acid was performed by the following method. (Moisture Concentration) The moisture concentration was measured using a Karl Fischer moisture meter (manufactured by Kyoto Electronics Industry, model MKS-1s). (Acrylic acid conversion rate) In the esterification reaction step, the acrylic acid conversion rate is determined by the concentration of acrylic acid (X) in the raw material liquid supplied to the reactor and the concentration of acrylic acid in the reaction liquid after the esterification reaction ( Y) and were determined by acid content titration, respectively, and were determined by the following equation.

Acrylic acid conversion rate (%) = (XY) / X × 100 Example 1 A cation exchange resin (DIA) wetted with water was placed in a reaction vessel of a fixed-bed reactor having a capacity of 500 mL.
ION PK-208, manufactured by Mitsubishi Chemical Corporation). While heating the reaction vessel to 65 ° C. in an oil bath, methanol was used as a solvent for dehydration at a flow rate of 120 mL / h.
The solution was passed for 15 hours at r to perform a dehydration step. At the end of the dehydration step, the water concentration at the outlet of the reaction vessel was 3.6% by weight. Then, while the reaction vessel was maintained at 65 ° C., the flow rate of acrylic acid was 70.4 mL / hr, and the flow rate of methanol was 4
9.6 mL / hr was continuously charged at the same time to start a synthesis reaction of methyl acrylate. Five hours after the start of the reaction, the conversion of acrylic acid was 78.5%.

Comparative Example 1 A synthesis reaction of methyl acrylate was started in the same manner as in Example 1 except that the dehydration step was not performed. As a result, the water concentration at the outlet of the reaction vessel immediately after the start of the synthesis reaction of methyl acrylate was 13.7.
%, And the conversion of acrylic acid after 5 hours from the start of the reaction was 24.2%. Example 2 A cation exchange resin (DIAI) wetted with water was placed in a reaction vessel of a 500 mL fluidized bed reactor having a stirring blade, a distillation column and a heating jacket.
155 mL (ONPK-208, manufactured by Mitsubishi Chemical Corporation) was charged. Further, 8.54% by weight of acrylic acid, 15.72% by weight of n-butanol, and 73.10% of n-butyl acrylate
% Liquid and 2.64% by weight of water
L was introduced. The slurry liquid was evacuated to 270 hPa while stirring at 300 revolutions per minute, heated in a heating jacket, and subjected to a ternary azeotropic distillation of water, n-butanol, and n-butyl acrylate to perform a dehydration step. Was. After the vapor generated by azeotropic distillation is condensed in a condenser, it is separated into an oil phase and an aqueous phase, and n-butanol and acrylic acid n
The oil phase consisting of -butyl was returned to the column as a reflux liquid, and the aqueous phase was wastewater. Also, at this time, since the liquid volume was reduced by using the aqueous phase as waste water, n-butanol was newly added to keep the liquid volume constant. This dehydration operation is 1
The operation was performed for 8 hours, and when the temperature in the reaction vessel reached 90 ° C., the dehydration step was completed. The water concentration in the reaction vessel at the end of the dehydration step was 1.1% by weight.

Next, after the temperature in the reaction vessel was lowered to 75 ° C., acrylic acid and 135.4 mL / hr and n-butanol were continuously charged simultaneously at 252.1 mL / hr.
The synthesis reaction of n-butyl acrylate was started. After 3 hours from the start of the reaction, the conversion of acrylic acid was 87.
3%. [Comparative Example 2] In the same manner as in Example 2, a cation exchange resin wetted with water, acrylic acid, n-butanol, n-butyl acrylate and water were placed in a reaction vessel of a fluidized bed reactor. And the slurry was stirred at 300 revolutions per minute, evacuated to 270 hPa, and heated with a heating jacket. Further, when the temperature in the reaction vessel reaches 75 ° C. (non-azeotropic state)
Then, acrylic acid and 135.4 mL / hr of n-butanol were simultaneously and continuously charged at 252.1 mL / hr, and a synthesis reaction of n-butyl acrylate was started. Acrylic acid n-
The water concentration in the reaction vessel immediately after the start of the butyl synthesis reaction is 1
It was 5.2% by weight, and the conversion of acrylic acid after 3 hours from the start of the reaction was 26.7%.

[0017]

According to the present invention, an excellent reaction yield can be obtained.
(Meth) acrylic acid esters can be produced.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Shiro Michichika 992, Nishioki, Okihama-shi, Aboshi-ku, Himeji-shi, Hyogo Nippon Shokubai Co., Ltd. Within Nippon Shokubai (72) Inventor Matsumoto Hatsugo, Himeji-shi, Hyogo 991 Okihama-shi, Nishioki, 992 Nippon Shokubai F-term (reference) 4H006 AA02 AC48 BA72 BA81 BD40 BD52 KA06 4H039 CA66 CD10 CD20

Claims (6)

[Claims] 1. A method for producing a (meth) acrylate ester using an alcohol and an acid as raw materials and using a cation exchange resin as a catalyst, wherein water impregnated in the cation exchange resin is treated with the alcohol, A method for producing a (meth) acrylic acid ester, wherein an esterification reaction step is carried out subsequent to a dehydration step of removing at least one selected from the acid and the generated ester as a solvent for dehydration. 2. The method for producing a (meth) acrylate according to claim 1, wherein the dehydration step is performed using a reaction vessel of a reactor for performing the esterification reaction step. 3. The method for producing a (meth) acrylate according to claim 1, wherein the cation exchange resin is washed with the solvent for dehydration in the dehydration step. 4. The method for producing a (meth) acrylate according to claim 1, wherein in the dehydration step, the solvent for dehydration is added to the cation exchange resin and distillation is performed. 5. The method for producing a (meth) acrylate according to claim 3, wherein the dehydration step is performed under reduced pressure. 6. A dehydration solvent is recovered from a waste liquid containing water and a dehydration solvent generated in the dehydration step, and the dehydration step and / or
The method for producing a (meth) acrylate according to any one of claims 1 to 5, wherein the method is reused in the esterification reaction step.