JPH05286904A - Production of allyl esters - Google Patents

Abstract

PURPOSE:To obtain an allyl ester by using an alcoholate of a specific alkaline earth metal as a catalyst and subjecting an aromatic carboxylic acid alkyl ester and allyl alcohol or methallyl alcohol to ester exchange. CONSTITUTION:An aromatic carboxylic acid alkyl ester (e.g. dimethyl terephthalate) is reacted with allyl alcohol or methallyl alcohol to give an aromatic carboxylic acid allyl or methallyl ester (e.g. allylmethyl terephthalate). In the reaction, an alcoholate of an alkaline earth metal of the formula (M is Ca or Ba; R<1> and R<2> are 1-8C alkyl or 3-5C alkenyl; (x) and (y) are both 0<=-<=2 rational number) (especially preferably calcium methylate or calcium ethylate) to carry out transesterification. Since the catalyst contains no heavy ion, this method has no problems in terms of treatment of waste. The reaction has a short reaction time and can provide a colorless product in high yield.

Description

Detailed Description of the Invention

[0001]

The present invention relates to an aromatic carboxylic acid, particularly an alkyl ester of phthalic acid, isophthalic acid, terephthalic acid or benzoic acid, and allyl alcohol or methallyl alcohol (hereinafter allyl and methallyl are referred to as (meth) allyl). (Hereinafter abbreviated)) to a corresponding allyl ester by a transesterification reaction.

[0002]

The target compound obtained by the above reaction has a radically polymerizable (meth) allyl group through an aromatic ester group. A polymer having excellent properties or optical properties can be obtained.

Conventionally, as a method for synthesizing this type of ester, (1) direct esterification reaction of a corresponding carboxylic acid and (meth) allyl alcohol. (2) Corresponding alkali metal salt of carboxylic acid and (meth)
Reaction with allyl chloride. (3) Reaction of corresponding carboxylic acid chloride with (meth) allyl alcohol. (4) Transesterification reaction between the corresponding alkyl ester of carboxylic acid and (meth) allyl alcohol. And the like.

When the method (1) is industrially performed, it usually requires pressurization at a high temperature and has a drawback that the product is easily colored. The method (2) requires an extra step for synthesizing the alkali metal salt of carboxylic acid, and the product is easily colored. Further, when an attempt is made to carry out the reaction in a water-alkali metal hydroxide-aromatic carboxylic acid- (meth) allyl chloride system, a large amount of (meth) allyl alcohol is by-produced. The method (3) has the drawback that not only is the carboxylic acid chloride expensive, but an additional chemical is required to capture the hydrochloric acid that forms. The method (4) is described in JP-A-48-28444, JP-A-48-97833, and JP-A-48-99136.
JP-A-48-103536, JP-A-56-71045
Japanese Unexamined Patent Publication (Kokai) Nos. 10-135242 and 9-31991 disclose a catalyst based on organotin, and a mixed catalyst of a zinc or manganese complex and an alkali metal alkoxide. However, both are expensive catalysts. The pollution problem remains not only when the used catalyst is disposed of, but also when it is disposed of.

Japanese Unexamined Patent Publication (Kokai) No. 62-12747 discloses a catalyst of an alkali metal carbonate or hydrogen carbonate. When the reaction is carried out with this catalyst, an alkali metal salt of a carboxylic acid produced as a by-product. Therefore, the reaction solution becomes a gel and it is not easy to separate the desired product from the reaction mixture.

Further, Japanese Patent Application Laid-Open No. 1-165549 discloses a method using a hydroxide or oxide of an alkaline earth metal as a catalyst, but in this method, the reaction rate is extremely slow and a sufficient conversion rate is obtained. It takes a long time to obtain it. In this type of reaction, what is mixed in addition to the target product is an unreacted product or a part of a plurality of ester functional groups of an aromatic polybasic acid ester that is exchanged with a (meth) allyl ester. The boiling point of such a compound is close to that of the desired product, and it is not easy to separate and purify the compound to the extent that it can be sufficiently distilled. Therefore, in order to obtain the desired product with high purity, it is necessary to increase the conversion rate as much as possible at the reaction stage.

Furthermore, in alkaline earth metal hydroxides or oxide catalysts, the water content of the reaction system rises, which causes the hydrolysis product of the ester, that is, the carboxylate, as a by-product, resulting in only a decrease in yield. However, it often happens that the solid-liquid separation after the reaction is disturbed.

[0008]

DISCLOSURE OF THE INVENTION An object of the present invention is to obtain a (meth) allyl ester of an aromatic carboxylic acid at a low cost in obtaining a (meth) allyl ester of an aromatic carboxylic acid by a transesterification reaction between an alkyl ester of an aromatic carboxylic acid and a (meth) allyl alcohol. It is an object of the present invention to provide a catalyst which is a highly active catalyst and gives an advantageous process in terms of solid-liquid separation after the reaction.

[0009]

Means for Solving the Problems The inventors of the present invention have made earnest studies on a catalyst for transesterification reaction of an alkyl ester of an aromatic carboxylic acid and a (meth) allyl alcohol, and as a result, the above-mentioned problems can be solved by using a specific catalyst. The inventors have found that the above can be solved and completed the present invention.

The present invention is represented by the following formula (I) when an aromatic carboxylic acid alkyl ester is reacted with a (meth) allyl alcohol to synthesize a (meth) allyl ester of an aromatic carboxylic acid. It is a process for producing allyl esters, which is characterized by using an alkaline earth metal alcoholate as a catalyst. When 0 <x + y ≦ 1 MO _1-xy (OR ¹ ) _x (OR ² ) _y (OH) _{x + y} or M (OR ¹ ) _x (OR ² ) _y (OH) _2-xy 1 ≦ x + y ≦ 2 M (OR ¹ ) _x (OR ² ) _y (OH) _2-xy
The above formula (I) (wherein M is calcium or barium, R ¹ and R ² may be the same or different, an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 3 to 5 carbon atoms, x and y). Is 0 ≦ x ≦ 2
And 0 ≦ y ≦ 2).

Examples of the carboxylic acid which constitutes the aromatic carboxylic acid allyl ester include monocyclic or polycyclic aromatic monobasic acids such as benzoic acid, naphthalenecarboxylic acid and biphenylcarboxylic acid, phthalic acid, isophthalic acid and terephthalic acid. Examples thereof include monocyclic or polycyclic aromatic dibasic acids such as naphthalenedicarboxylic acid, biphenyldicarboxylic acid, and diphenyletherdicarboxylic acid, and aromatic polybasic acids such as trimellitic acid and pyromellitic acid.

As the alcohol component constituting the aromatic carboxylic acid alkyl ester, methanol, ethanol, n-propanol, isopropanol, octyl alcohol, ethylene glycol, propylene glycol, tetramethylene glycol, tetraethylene glycol, hexamethylene glycol or the like is used. Can be mentioned.

R ¹ in the catalyst structure represented by the above formula (I)
Examples of the group or R ² group include methyl group, ethyl group, isopropyl group, n-propyl group, isobutyl group, n-butyl group, t-butyl group, isoamyl group, n-amyl group, n-
Hexyl group, octyl group, 2-ethylhexyl group, allyl group, methallyl group, butenyl group, pentenyl group and the like can be mentioned.

The catalyst represented by the formula (I) is commercially available, but may be synthesized by any of the following methods. (A) Reaction of alkaline earth metal with alcohol (B) Reaction of alkaline earth metal carbide with alcohol (C) Reaction of alkaline earth metal hydride with alcohol (D) With alkaline earth metal hydroxide Reaction with alcohol (E) Reaction of alkaline earth metal oxide with alcohol (F) Reaction of halide of alkaline earth metal with metal (excluding alkaline earth metal) alcoholate (G) of alkaline earth metal alcoholate Partial hydrolysis

The above-mentioned reactions (A) to (E) are usually carried out by using 0.1 to 10000 moles of alcohol with respect to the alkaline earth metal compound and reacting at 0 to 200 ° C. for 0.5 hours to 2 weeks. It can be carried out. In the above reaction, a solvent inert to the alkaline earth metal alcoholate can be used together. The alcohol used in the above reaction may be a single type, or a plurality of types of alcohol may be mixed or added in a fixed order. After the reaction, the unreacted alcohol or solvent may be removed by distillation, but the catalyst may be used as it is in the presence of the alcohol or solvent.

The reaction of the above (F) uses 0.1 to 3 mole times of metal (excluding alkaline earth metal) alcoholate with respect to the alkaline earth metal halide, in the presence of the corresponding alcohol, or with respect to the raw material. It can be carried out by reacting at -20 ° C to 200 ° C for 10 minutes to 2 days in the presence or absence of an inert solvent. When a solvent or an excess alcohol is used, the solvent or alcohol may be removed by filtration or distillation after the reaction, but it may be used as it is in a state in which the alcohol or solvent coexists. The metal halide (excluding alkaline earth metal) formed may be removed by an appropriate method, but it can be used as it is in the coexisting state.

In the reaction (G) above, in the formula (I), an appropriate amount of water is added to the alkaline earth metal alcoholate having a certain value of x and y to cause a reaction, and the reaction is different from the starting material x.
It is a reaction that produces an alkaline earth metal alcoholate having a value of + y. The optimum amount of water to use can easily be determined by simple experimentation. The reaction can be carried out at 0 ° C. to 200 ° C. for 10 minutes to 2 days in the presence or absence of a solvent inert to the alkaline earth metal alcoholate. When a solvent is used, the solvent may be removed by filtration or evaporation after the reaction, but it may be used as it is in the presence of the solvent.

The alkaline earth metal alcoholate in the catalyst is preferably calcium alcoholate, and the alcohol is preferably methanol or ethanol. Since the compound produced in the transesterification reaction is an allyl ester of an aromatic carboxylic acid,
It is possible to use allyl alcohol as the alcohol, but methanol or ethanol is more suitable for the calcium alcoholate formation reaction because of its higher activity.
In particular, when methyl ester or ethyl ester of aromatic carboxylic acid is used as a raw material for the transesterification reaction, the use of calcium methylate or calcium ethylate as a catalyst is advantageous because impurities of impurities can be avoided. It is industrially advantageous to use calcium hydroxide or calcium oxide as the calcium source in the production method of such a catalyst. It is particularly preferable to use calcium oxide from the viewpoint of activity.

The transesterification reaction of the present invention is carried out by heating an alkyl ester of an aromatic carboxylic acid and a (meth) allyl alcohol in the presence of a catalyst represented by the formula (I). The reaction temperature is 20 to 170 ° C., preferably 2
A range of 0 to 125 ° C., more preferably 90 to 110 ° C. is suitable. The reaction pressure may be atmospheric pressure or high pressure, and if necessary, reduced pressure. Further, the alkyl alcohol produced by the transesterification reaction may be removed to the outside of the system if necessary. The amount of (meth) allyl alcohol used at the start of the reaction is preferably as large as possible with respect to the number of equivalents of the ester group of the aromatic carboxylic acid alkyl ester, but in terms of production efficiency per reactor, 1.1 The range of 10 to 10 times, preferably 1.2 to 8 times is suitable. (Meta)
When part of allyl alcohol is distilled out of the reaction system, (meth) allyl alcohol may be appropriately added. The water content in the reaction system is preferably as low as possible.

The amount of the catalyst to be used is 0.01 to 5% by weight, preferably 0.02 to 3 as an external number with respect to the raw material ester.
Weight percent is suitable. If the amount of the catalyst used is less than this range, a high conversion cannot be obtained, and if it exceeds this range, the effects of side reactions and the like become large and the economic efficiency also decreases. The total amount of the catalyst may be added at the beginning of the reaction, if necessary, or may be sequentially added as the reaction progresses.

The aromatic carboxylic acid (meth) allyl ester produced by the present invention can be isolated by distilling off the remaining (meth) allyl alcohol and then purifying by an appropriate method such as distillation. .. As needed (meta)
Before or after distilling off allyl alcohol, a small amount of water or the like may be added to deactivate the catalyst. Further, if necessary, preliminary purification such as filtration, washing with water, pickling or alkali washing may be performed in advance.

[0022]

EXAMPLES The present invention will be described below with reference to examples. The gas chromatography used in Examples and Comparative Examples is OV-
The yield was determined by quantitative analysis using a 170 125 m capillary column and dibutyl phthalate as an internal standard.

Example 1 1 g of calcium oxide was added to 10 ml of methanol to prepare a slurry, which was heated under reflux for 5 hours. By filtering and drying this, 1.5 g of a white powder was obtained. As a result of analysis, it was found that Ca (OCH ₃ ) _1.1 (OH)
It was confirmed to be calcium methylate having a composition of _0.9 . Next, 100 g of dimethyl terephthalate, 150 g of allyl alcohol and 0.5 g of the above-mentioned calcium methylate as a catalyst were added to a 300 ml four-necked flask equipped with a stirrer, a steam distillation outlet, and a thermometer, and immersed in an oil bath at 120 ° C. As the reaction proceeded, allyl alcohol containing methanol began to distill from the vapor distillation outlet. The methanol content in the distillate was analyzed, and the reaction was carried out for 8 hours while adding allyl alcohol corresponding to the distillate amount to the reactor.
The temperature of the reaction solution was 92 to 105 ° C. When the reaction liquid after completion of the reaction was analyzed by gas chromatography, it was found that diallyl terephthalate was produced in a yield of 97.5% based on dimethyl terephthalate. After distilling off the remaining allyl alcohol, it was subjected to vacuum distillation to yield 140 to 1
A colorless fraction at 43 ° C./0.9 mmHg was obtained in 121 g (isolated yield 95%). According to gas chromatography, the purity of this product was 99.5% by weight, and the balance of 0.
It was confirmed that 5% by weight was allyl methyl terephthalate. The APHA number of this product was 5 or less.

Example 2 When 100 g of dimethyl terephthalate as raw material, 150 g of allyl alcohol and 0.5 g of calcium diethylate Ca (OC ₂ H ₅ ) ₂ as catalyst were used and the reaction was carried out in the same manner as in Example 1, the reaction was carried out. After 8 hours, diallyl terephthalate was produced in a yield of 98.5% based on dimethyl terephthalate. Purification was carried out in the same manner as in Example 1 to obtain 122 g of a colorless fraction (isolation yield 96%).
The purity by gas chromatography was 99.8% by weight, and the remaining 0.2% by weight was allylmethyl terephthalate. The APHA number of this product was 5 or less.

Example 3 1 g of calcium oxide was added to a mixed solution of 5 ml of methanol and 5 ml of allyl alcohol to prepare a slurry, which was heated under reflux for 7 hours. This was filtered and dried to obtain 1.6 g of calcium methylallyl alcoholate white powder. Using 100 g of dimethyl terephthalate as a raw material, 150 g of allyl alcohol, and 0.5 g of calcium methylallyl alkoxide as a catalyst, the reaction was carried out in the same manner as in Example 1. The reaction time was 12 hours, and the yield was 98.2% based on dimethyl terephthalate. Diallyl terephthalate was produced at a rate. Purification was carried out in the same manner as in Example 1 to obtain 122 g of a colorless fraction (isolation yield 96%). The purity by gas chromatography was 99.6% by weight, and the remaining 0.4% by weight was allylmethyl terephthalate. The APHA number of this product was 5 or less.

Example 4 When a reaction was carried out in the same manner as in Example 1 using 100 g of dimethyl isophthalate as a raw material, 150 g of allyl alcohol and 0.2 g of barium isopropyl alcoholate as a catalyst, the reaction time was 10 hours with respect to dimethyl isophthalate. Diallyl isophthalate was produced in a yield of 95.0%. Purification was performed in the same manner as in Example 1 to obtain 117 g of a colorless fraction (isolation yield: 92%). The purity by gas chromatography was 99.3% by weight, and the remaining 0.7% by weight was allylmethylisophthalate.
The APHA number of this product was 5 or less.

Example 5 Using 100 g of methyl benzoate as a raw material, 107 g of allyl alcohol and 0.5 g of the calcium methylate obtained in Example 1 as a catalyst, a reaction was carried out in the same manner as in Example 1 and the reaction was carried out. After 7 hours, allyl benzoate was obtained in a yield of 97.8%.

Comparative Examples 1 to 3 The transesterification reaction was carried out in the same manner as in Example 1 except that 100 g of dimethyl isophthalate, 150 g of allyl alcohol, and the catalysts shown in Table 1 were used as raw materials. The results are also shown in Table 1.

[0029]

[Table 1]

As shown in Table 1, when only calcium hydroxide or calcium oxide is used as a catalyst, the initial reaction rate is slow and the reaction takes a long time as a whole. When sodium methylate is used, the initial reaction rate is fast, but it takes a long time to obtain a sufficient conversion rate, and the solution is easily colored. In addition, the amount of precipitation of the reaction solution is large and separation is difficult.

[0031]

Although the mechanism of action of the catalyst used in the method of the present invention is not clear, the catalytically active species in this reaction are alkaline earth metal formed by the reaction of the alkaline earth metal alcoholate and (meth) allyl alcohol. It is presumed to be a metal (meth) allyl alcoholate. Even in the alkaline earth metal hydroxide or oxide, which is a known catalyst, the alkaline earth metal (meth) is generated in the transesterification reaction system.
The formation of allyl alcoholate is considered, but at that time, not only it takes a considerably long time until the active species are formed, but also the formation of water is observed, and the produced water acts on the hydrolysis reaction of the ester and the solid-liquid It adversely affects the purification process such as separation. According to the method of the present invention, such a problem does not occur and a colorless product can be obtained in a good yield in a short reaction time. If it is difficult to obtain an alkaline earth metal alcoholate as a catalyst, it is possible to make a catalyst by reacting an easily available hydroxide or oxide of an alkaline earth metal with an alcohol, especially when methanol or ethanol is used. Is very industrially advantageous because the corresponding alcoholate can be easily obtained. Further, since the catalyst itself does not contain heavy metal ions, there is no problem in waste treatment.

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[Procedure amendment]

[Submission date] June 24, 1992

[Procedure Amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] Claim 1

[Correction method] Change

[Correction content]

 ─────────────────────────────────────────────────── ─── Continued Front Page (72) Inventor Shizuo Takeda 783-50 Takaoka-cho, Matsuyama-shi, Ehime Prefecture (72) Inventor Toru Kitamura 1-2-2 Matsumae-cho, Matsuyama-shi, Ehime Prefecture

Claims (6)

[Claims] 1. When synthesizing an allyl ester or methallyl ester of an aromatic carboxylic acid by reacting an aromatic carboxylic acid alkyl ester with allyl alcohol or methallyl alcohol, an alkaline earth represented by the following formula (I): A process for producing allyl esters, which comprises using an alcoholate of a metal group as a catalyst. When 0 <x + y ≦ MO _1-xy (OR ¹ ) _x (OR ² ) _y (OH) _{x + y} or M (OR ¹ ) _x (OR ² ) _y (OH) _2-xy 1 ≦ x + y ≦ 2 When M (OR ¹ ) _x (OR ² ) _y (OH) _2-xy
Formula (I) (wherein M is calcium or barium, R ¹ , R
² may be the same or different, and is an alkyl group having 1 to 8 carbon atoms or an alkenyl group having 3 to 5 carbon atoms, and x and y are 0 ≦ x.
Rational numbers ≦ 2 and O ≦ y ≦ 2 are shown). 2. The aromatic carboxylic acid alkyl ester is a dimethyl ester of phthalic acid, isophthalic acid or terephthalic acid or a methyl ester of benzoic acid.
The manufacturing method described. 3. The alkaline earth metal alcoholate represented by the formula (I), wherein y = 0 and R ¹ is a methyl group, an ethyl group, an isopropyl group, an allyl group or a methallyl group. The manufacturing method described in. 4. The method according to claim 3, wherein in the alkaline earth metal alcoholate represented by the formula (I), M is calcium, y = 0, and R ¹ is a methyl group or an ethyl group. 5. A method for producing the calcium methylate or calcium ethylate according to claim 4, which comprises reacting calcium oxide with methanol or ethanol. 6. The alkaline earth metal alcoholate represented by the above formula (I), wherein R ¹ is a methyl group or an ethyl group, and R ² is an allyl group or a methallyl group. Manufacturing method.