JP2001187763A - Method for producing (meth)acrylic ester - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a (meth)acrylic ester by transesterification reaction by which the precipitation of a solid is hardly caused even if the temperature is lowered, and the formation of byproducts is little. SOLUTION: This method for producing the (meth)acrylic ester by subjecting an alkyl (meth)acrylate, and a 3-20C alcohol or phenols as raw materials to the transesterification reaction comprises using a reaction product obtained by bringing a dialkyltin oxide with a (meth)acrylic acid corresponding to the objective (meth)acrylic ester, as a catalyst.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a (meth) acrylate by a transesterification reaction.

[0002]

2. Description of the Related Art Heretofore, as a method for producing a (meth) acrylate ester by a transesterification reaction, a method using a dialkyltin oxide as a catalyst is known. However, since dialkyltin oxide is a solid, even when it is dissolved in a high-temperature liquid such as a reaction solution during a reaction, a solid may be precipitated at a low temperature or when the temperature decreases after the reaction. . Therefore, in the actual production process, when the liquid containing the catalyst is sent from the container to the reactor, or when the liquid after the reaction is sent to the distillation column, if the liquid temperature drops, solids will precipitate and clog the pipes. Inconvenience may occur.

On the other hand, JP-A-53-34714 discloses a method for producing (meth) acrylic acid ester by transesterification using dibutyltin dicarboxylate which is a liquid as a catalyst. I have.

[0004]

However, when dibutyltin dicarboxylate is used, the starting alcohol or by-produced alcohol is added to the double bond of the starting alkyl (meth) acrylate or the desired (meth) acrylate. There is a problem that a Michael adduct is generated by the side reaction (Michael addition reaction), and the yield and purity of the (meth) acrylic acid ester decrease. Further, there is a problem that a carboxylic acid ester derived from the catalyst is generated.

The present invention has been made in view of such a problem, and is a method for producing a (meth) acrylate ester by a transesterification reaction. Low generation of by-products (meta)
An object of the present invention is to provide a method for producing an acrylate ester.

[0006]

According to the present invention, there is provided a method for transesterifying (meth) acrylic acid in the presence of a catalyst using an alkyl (meth) acrylate and an alcohol or phenol having 3 to 20 carbon atoms as raw materials. In the method for producing an ester, a reaction product obtained by contacting a dialkyltin oxide with a (meth) acrylic acid corresponding to a target (meth) acrylic acid ester is used as the catalyst, wherein (meth) acrylic acid is used. The present invention relates to a method for producing an ester.

However, an alcohol which is eliminated from the starting material alkyl (meth) acrylate by a transesterification reaction,
The alcohol is different from the alcohol having 3 to 20 carbon atoms as the raw material.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst used in the present invention is a reaction product obtained by contacting a dialkyltin oxide with a (meth) acrylic acid corresponding to a target (meth) acrylate. Since this reaction product is a liquid, there is no problem such as solid precipitation, and as shown in Examples described later, the generation of Michael adduct is small, and the (meth) acrylic acid corresponding to the target (meth) acrylic ester is obtained. By using the compound (1), the desired (meth) acrylic acid ester having a high purity can be obtained because different (meth) acrylic acid is not mixed.

As the dialkyltin oxide used here, a dialkyltin oxide represented by the following formula (1) is preferable.

[0010]

Embedded image In the formula, R ¹ represents an alkyl group having 1 to 18 carbon atoms, particularly preferably an alkyl group having 1 to 8 carbon atoms. Specific examples of preferable dialkyltin oxide include compounds such as dimethyltin oxide, methylethyltin oxide, diethyltin oxide, dipropyltin oxide, dibutyltin oxide, dioctyltin oxide, and diphenyltin oxide.

The (meth) acrylic acid to be brought into contact with these dialkyltin oxides is (meth) acrylic acid corresponding to the desired (meth) acrylate, and when the target product is an acrylate, acrylic acid When the target product is methacrylic acid ester, methacrylic acid is used. The amount of the (meth) acrylic acid to be contacted is 0.1 to 1 mol of the dialkyltin oxide.
5 to 4 moles are preferable, and 1 to 2 moles are particularly preferable.

The contacting method is not particularly limited, and a mixture of dialkyltin oxide and (meth) acrylic acid is mixed at a temperature of about 10 to 100 ° C, preferably 15 to 40 ° C.
The catalyst can be easily obtained by stirring until the dialkyltin oxide is dissolved. At this time, a solvent is not required, but if operation is necessary for preventing coagulation of (meth) acrylic acid and the like, a raw material alkyl (meth) acrylate or a raw material alcohol used for the transesterification reaction can be used.

On the other hand, alcohols or phenols used as a raw material include alcohols having 3 to 2 carbon atoms.
0 and phenols have 6 to 20 carbon atoms.

Examples of the alcohol having 3 to 20 carbon atoms include alkanols, alkoxyalkanols, alkenoxyalkanols, alkenols, phenoxyalkanols, cycloalkanols, alkylcycloalkanols, cycloalkylalkanols,
Examples include phenylalkanols, alkylphenylalkanols, haloalkanols, cyanoalkanols, aminoalkanols and the like. Among these, alkanols, alkenols and aminoalkenols are preferred, and alkanols are particularly preferred.

Specifically, n-propanol, isopropanol, n-butanol, isobutanol, tert-butanol, n-pentanol, n-hexanol, n-heptanol, n-octanol, 2-ethylhexanol, lauryl alcohol, Stearyl alcohol, tridecanol, dimethylaminoethanol, diethylaminoethanol, cyclohexanol, 3,
3,5-trimethylcyclohexanol, 4-tert-butylcyclohexanol, phenol, benzyl alcohol, 1-phenylethyl alcohol, 2-phenylethyl alcohol, phenoxyethanol, methoxyethanol, ethoxyethanol, butoxyethanol, allyl alcohol, methallyl alcohol And the like.

The alkyl (meth) acrylate used as the other raw material is not particularly limited as long as it is capable of transesterification with the raw material alcohol, but is usually an inexpensive material such as methyl methacrylate, methyl acrylate or butyl acrylate. Compounds are preferred.

In this case, the starting material alkyl (meth) acrylate is selected such that the alcohol eliminated from the starting material alkyl (meth) acrylate by transesterification is different from the starting material alcohol having 3 to 20 carbon atoms. .
Generally, the reaction is carried out while removing the alcohol to be eliminated by distillation, so that the alcohol which is eliminated from the alkyl (meth) acrylate as the raw material has 3 to 20 carbon atoms in the raw material.
It is chosen to have a lower boiling point than the alcohol. Therefore, methyl (meth) acrylate or methyl acrylate is most preferred as the starting alkyl (meth) acrylate.

In the transesterification reaction, the mixing ratio of the raw material alkyl (meth) acrylate and the raw material alcohol is preferably 1 to 10 mol, more preferably 1 to 3 mol, per mol of the raw material alcohol.
Molar is preferred.

The amount of the catalyst used in the transesterification reaction is preferably from 0.01 to 10 mol%, more preferably from 0.1 to 10 mol%, as tin content, per mol of the starting alcohol.
5 mol% is preferred.

The reaction temperature of the transesterification is usually from 60 to
It is desirable to carry out at 150 ° C. The reaction pressure is reduced pressure, normal pressure,
It can be carried out under any pressure. It is preferable that alcohol produced as a by-product with the progress of the reaction be removed to the outside of the reaction system. Removal is particularly preferred. As the type of the transesterification reaction, for example, a commonly used reaction such as a batch reaction or a continuous reaction can be used.

The resulting reaction solution contains the desired (meth) acrylate, unreacted starting alkyl (meth) acrylate, unreacted starting alcohol and catalyst. The target (meth) acrylate ester can be obtained with high purity and high quality by further distilling the reaction solution under reduced pressure or by extraction.

At the time of transesterification or distillation, a polymerization inhibitor may be appropriately used. As the polymerization inhibitor, those usually used may be used. For example, hydroquinone, hydroquinone monomethyl ether, phenothiazine, N-oxyl compound and the like can be used.

[0023]

The present invention will be described below with reference to examples and comparative examples, but the present invention is not limited to these examples. The components in the reaction mixture were analyzed by gas chromatography. In addition, the definition of the conversion rate used in this specification is as follows.

Conversion (%) = (moles of reacted starting alcohol / moles of supplied starting alcohol) × 100 <Example 1> 19.85 g of dibutyltin oxide was placed in a 100 mL three-necked flask equipped with a stirrer and a thermometer. And 7.67 g of acrylic acid were charged and stirred at 20 ° C. After 1 hour, the dibutyltin oxide dissolves and the catalyst solution 27.
52 g were obtained.

Using a distillation apparatus equipped with a 20-stage Oldershaw distillation column, 1051.1 g of methyl acrylate (hereinafter referred to as MA) (12.
2 mol), N, N-dimethylaminoethanol 490.
3 g (5.5 mol), 0.8 g of phenothiazine and 27.52 g of the catalyst solution were added, and the mixture was stirred to perform a transesterification reaction for 6 hours. During this time, methanol produced by the reaction was removed from the system by azeotropy with MA while maintaining the 15th stage from the bottom of the distillation column at 65 ° C. At this time, the reaction temperature is 80
The temperature changed from 0 ° C to 100 ° C. When the reaction solution was analyzed by gas chromatography, the conversion of N, N-dimethylaminoethanol was 95.25%. The Michael adduct concentration in this reaction solution was 0.02% or less in total. The reaction-terminated liquid was yellow and transparent, and no suspended crystals were observed even when cooled. Next, this reaction solution was distilled under reduced pressure to recover unreacted low-boiling components such as MA and N, N-dimethylaminoethanol.
675 g of N, N-dimethylaminoethyl acrylate (analysis result by gas chromatography) was obtained.

<Comparative Example 1> A transesterification reaction was conducted for 6 hours in the same manner as in Example 1 except that 19.58 g of dibutyltin oxide was used instead of the catalyst solution, and the results shown in Table 1 were obtained. Further, the catalyst was precipitated as the reaction-terminated liquid was cooled. Unreacted low-boiling components were recovered in the same manner as in Example 1 to obtain 662 g of N, N-dimethylaminoethyl acrylate having a purity of 99.58%.

Example 2 In the same apparatus as in Example 1, 19.85 g of dibutyltin oxide and 7.67 of acrylic acid were used.
g and 10 g of MA were charged and stirred at 20 ° C. One hour later, the catalyst was dissolved to obtain 37.52 g of a catalyst solution.

In Example 1, this catalyst solution 37.5
A transesterification reaction was performed for 6 hours in the same manner as in Example 1 except that 2 g was used, and the results in Table 1 were obtained. The reaction-terminated liquid was yellow and transparent, and no suspended crystals were observed even when cooled. Unreacted low-boiling components were recovered in the same manner as in Example 1, and 673 g of N, N-dimethylaminoethyl acrylate having a purity of 99.79% was obtained.

Example 3 18.8 g of dibutyltin oxide and 6.5 g of methacrylic acid were placed in the same apparatus as in Example 1.
And stirred at 18 ° C. After 1 hour the catalyst dissolves,
25.3 g of a catalyst solution were obtained.

The reactor used in Example 1 was charged with 1185.2 g (11.8) of methyl methacrylate (hereinafter referred to as MMA).
4 mol), N, N-dimethylaminoethanol 470.
2 g (5.28 mol), phenothiazine 0.8 g, and a catalyst solution 25.3 g were added, and the mixture was stirred and transesterified for 6 hours. During this time, the methanol produced in the reaction is MM
By azeotroping with A, the 15th stage from the bottom of the distillation column was removed from the system while maintaining the temperature at 67 ° C. At this time, the reaction temperature was 95 ° C.
To 115 ° C. Table 1 shows the results of the analysis of the reaction solution.
It is as follows. The reaction-terminated liquid was yellow and transparent, and no suspended crystals were observed even when cooled. Next, this reaction solution was distilled under reduced pressure in the same manner as in Example 1 to obtain unreacted MMA,
Low-boiling components such as N, N-dimethylaminoethanol were recovered, and 741 g of N, N-dimethylaminoethyl methacrylate having a purity of 100% was obtained. <Comparative Example 2> A transesterification reaction was performed for 6 hours in the same manner as in Example 3 except that 18.8 g of dibutyltin oxide was used instead of the catalyst solution, and the results shown in Table 1 were obtained. Further, the catalyst was precipitated as the reaction-terminated liquid was cooled. Next, unreacted low-boiling components were recovered in the same manner as in Example 3, and 718 g of N, N-dimethylaminoethyl methacrylate having a purity of 99.60% was obtained.
I got

Example 4 18.8 g of dibutyltin oxide and 6.5 g of methacrylic acid were prepared in the same apparatus as in Example 1.
And 10 g of MMA were charged and stirred at 18 ° C. After 1 hour, the catalyst was dissolved to obtain 35.3 g of a catalyst solution.

In Example 3, the catalyst solution 35.3 was used.
Transesterification was carried out for 6 hours in the same manner as in Example 3 except that g was used, and the results in Table 1 were obtained. The reaction-terminated liquid was yellow and transparent, and no suspended crystals were observed even when cooled. Next, unreacted low-boiling components were recovered in the same manner as in Example 3, and 732 g of N, N-dimethylaminoethyl acrylate having a purity of 99.76% was obtained.

<Embodiment 5> An MM is used in the apparatus used in Embodiment 1.
A891.6 g (8.9 mol), 2-ethylhexanol 828.1 g (6.4 mol), phenothiazine 0.8
g and 1.5 g of the catalyst solution obtained in the same manner as in Example 3, and the mixture was stirred to carry out a transesterification reaction for 5 hours. During this time, methanol generated by the reaction was removed from the system by azeotropy with MMA. At this time, the reaction was performed while reducing the pressure so that the reaction temperature did not exceed 140 ° C. Table 1 shows the results of the analysis of the reaction solution. Next, this reaction solution was distilled under reduced pressure in the same manner as in Example 1 to recover unreacted low boiling components such as MMA and 2-ethylhexanol, and to obtain 1159 g of 2-ethylhexyl methacrylate having a purity of 100%. .

Comparative Example 3 A reaction was carried out in the same manner as in Example 5 except that 0.8 g of dibutyltin oxide was used instead of the catalyst solution. The transesterification was performed for 5 hours, and the results shown in Table 1 were obtained. Next, unreacted low-boiling components were recovered in the same manner as in Example 5, and 1127 g of 2-ethylhexyl methacrylate having a purity of 100% was obtained.

Example 6 In the same apparatus as in Example 1, 28.80 g of dioctyltin oxide and 7.6 of acrylic acid were used.
7 g and 10 g of MA were charged and stirred at 21 ° C. 1
After an hour, the catalyst was dissolved to obtain 46.47 g of a catalyst solution.

In Example 1, the catalyst solution 46.5 was used.
Transesterification was carried out for 6 hours in the same manner as in Example 1 except that g was used, and the results in Table 1 were obtained. The reaction-terminated liquid was yellow and transparent, and no suspended crystals were observed even when cooled. Next, the reaction solution was distilled under reduced pressure in the same manner as in Example 1 to recover unreacted low-boiling components such as MA and N, N-dimethylaminoethanol.
670 g of N, N-dimethylaminoethyl acrylate
I got

[0037]

[Table 1]

[0038]

According to the present invention, when a (meth) acrylic acid ester is produced by a transesterification reaction, no solid is deposited even when the temperature is lowered, which is industrially advantageous. It is possible to provide a production method capable of obtaining a highly pure (meth) acrylic acid ester with little generation and high selectivity.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI theme coat ゛ (reference) // C07B 61/00 300 C07B 61/00 300 F term (reference) 4G069 AA06 AA08 BA21C BA27A BA27B BC22A BC22B BC22C BE01C BE08A BE08B BE08C CB17 DA02 FA01 FC02 4H006 AA02 AC48 BA11 BA30 BA81 BJ50 4H039 CA66 CD10 CD40

Claims (3)

[Claims] 1. A method for producing a (meth) acrylate ester, which comprises subjecting a transesterification reaction in the presence of a catalyst using an alkyl (meth) acrylate and an alcohol or phenol having 3 to 20 carbon atoms as raw materials, A method for producing a (meth) acrylic ester, comprising using, as a catalyst, a reaction product obtained by contacting a dialkyltin oxide with a (meth) acrylic acid corresponding to a target (meth) acrylic ester. (However,
An alcohol desorbed from an alkyl (meth) acrylate as a raw material by a transesterification reaction;
It is an alcohol different from alcohol 0. ) 2. The (meth) acrylic acid according to claim 1, wherein the catalyst is an organotin compound obtained by stirring a dialkyltin oxide and (meth) acrylic acid at 10 to 100 ° C. Method for producing ester. 3. The dialkyltin oxide to be brought into contact with (meth) acrylic acid is represented by the following formula (1): The method for producing a (meth) acrylate according to claim 1 or 2, wherein R ¹ is a dialkyltin oxide represented by the formula: wherein R ¹ represents an alkyl group having 1 to 18 carbon atoms. .