JPS585178B2 - 4,4'-(ethylenedioxy) bisanthocarboxylic acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an improved method for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester. and 4,4', which are partially precipitated from the reaction solution obtained by heating in the presence of an anhydrous polar solvent.
- (Ethylenedioxy)bisbenzoic acid ester and alkali halide are separated, further dehydrated by concentration and decarbonated, and then heated again in the presence of an alkali carbonate and an anhydrous polar solvent. 4, 4'-
This invention relates to a method for producing (ethylenedioxy)bisbenzoic acid ester.

Conventionally, Japanese Patent Publication No. 47-15338 and Japanese Patent Publication No. 47-27089 are known as methods for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester using alkali carbonate as an alkali source; According to Japanese Patent Publication No. 47-1533, there is a method for producing 4゜4'-(ethylenedioxy)bisbenzoic acid ester by circulating the intermediate p-(2-chloroethoxy)benzoic acid ester.
In 8, ethylene dichloride was used in large excess compared to the theoretical amount of p-oxybenzoic acid ester, and once p-(2-
Selectively produce chloroethoxy)benzoic acid ester,
A method is disclosed in which this is purified by distillation under reduced pressure and then reacted again with p-oxybenzoic acid ester.

However, in such a method, since 2 to 3% of p-oxybenzoate alkali salt is present in the reaction mother liquor, p-(
In order to prevent decomposition that occurs during vacuum distillation of 2-chloroethoxy(benzoic acid ester) at high temperatures and operational losses due to distillation, the equipment becomes extremely complicated.

Furthermore, 4,4'-(ethylenedioxy) is present in the reaction mother liquor.
It contains 5 to 6% bisbenzoic acid ester, which remains in the distillation residue together with other side reactants, which has the drawback of requiring a great deal of effort for purification.

Moreover, according to Japanese Patent Publication No. 15338/1984, a method is disclosed in which 4.4'(ethylenedioxy)bisbenzoate is obtained by heating p-oxybenzoic acid ester and ethylene dichloride in a polar solvent at a temperature of about 65 to 70%. has been done.

In this reaction, some unreacted p-oxybenzoic acid ester and p-(2-chloroethoxy)benzoic acid ester are contained in the reaction system, but even if the reaction time is further increased, the yield remains low. Almost unchanged, ester hydrolysis and p
-(2-Hydroxyethoxy)benzoic acid ester and other side-reactants are significantly produced, and even worse, the separation of the target product 4,4'-(ethylenedioxy)bisbenzoic acid ester from the reaction mother liquor is reduced. Makes refining difficult.

In view of these points, the present inventors conducted intensive studies on an industrially advantageous manufacturing method for 4,4'-(ethylenedioxy)bisbenzoate, and as a result, they discovered that p-oxybenzoate and ethylene dichloride were combined together. The reaction proceeded by heating in the presence of an alkali carbonate and an anhydrous polar solvent is stopped when the conversion of p-oxybenzoic acid ester is between 35 and 85, and the resulting reaction mixture is separated by filtration of crystals.

Then, by concentrating the reaction solution, it is a decomposition product of the neutralization reaction between p-hydroxybenzoic acid ester and alkali carbonate.

It is possible to efficiently produce 4,4'-(ethylenedioxy)bisbenzoic acid ester by separating the still dissolved carbon dioxide gas and water and heating it again in the presence of an alkali carbonate and an anhydrous polar solvent. They discovered what they could do and completed the present invention.

That is, in the present invention, p-oxybenzoic acid ester and ethylene dichloride are heated in the presence of an alkali carbonate and an anhydrous polar solvent (hereinafter abbreviated as the first stage reaction).

), 4,4'-( partially precipitated from the resulting reaction solution
Ethylenedioxy)bisbenzoic acid ester and alkali chloride are separated, further concentrated and dehydrated, and then heated again in the presence of an alkali carbonate and an anhydrous polar solvent (
Hereinafter, this will be abbreviated as post-stage reaction.

) is a method for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester.

By the production method of the present invention, 4.4'-(ethylenedioxy)
When bisbenzoic acid ester was manufactured,
Compared to the method of No. 338, the yield based on p-oxybenzoic acid ester is improved by more than 10%, and the yield of by-products such as ester hydrolyzate, phenol, and p-(2-hydroxyethoxy)benzoic acid ester is improved by more than 10%. Due to the decrease, 4.4'-
Separability of (ethylenedioxy)bisbenzoic acid ester from the reaction mother liquor and heat filtration properties during recrystallization are improved.

Furthermore, the content of impurities with free carboxylic acid contained in the 4.4'-(ethylenedioxy)bisbenzoic acid ester (hereinafter abbreviated as acid value).

) is 0.05X10-6 equivalent/g or less, and 1/ of the value (0.5X 10-6 equivalent/g) produced by a known method.
Improved to 10 or less.

Details are shown in Examples and Comparative Examples. Further, to explain an example of the present invention, as a first stage reaction, 1 mol of methyl p-oxybenzoate, 0.86 mol of ethylene dichloride, 0.76 mol of sodium carbonate, and 200 g of methanol are heated in an autoclave at 165°C for 2 hours. .

When the crystals precipitated from the reaction mother liquor at room temperature are separated by filtration, the crystals contain methyl 4.4'-(ethylenedioxy)bisbenzoate with a yield of 55%, and the reaction mother liquor contains p. -18% methyl oxybenzoate, 16% methyl p-(2-chloroethoxy)benzoate and 4.4'-(
Contains 4% methyl ethylenedioxy)bisbenzoate.

Further, this reaction mother liquor contained 0.4 mol of water.

When this reaction mother liquor is concentrated and dehydrated at 65 to 120° C. under normal pressure, the water content in the concentrate becomes 0.04 mol.

100 g of methanol and 10.6 g of sodium carbonate were added to the concentrate and heated in an autoclave at 170° C. for 1.5 hours to obtain 23% methyl 4,4'-(ethylenedioxy)bisbenzoate.

The total yield of methyl 4.4'-(ethylenedioxy)bisbenzoate is 78%.

Also, each 4゜4 obtained by this two-stage reaction
No difference was observed in the quality of methyl ′-(ethylenedioxy)bisbenzoate.

The alkyl p-oxybenzoate used in the present invention is p-
The reaction solvent that can be used in the present invention, which is a lower alcohol ester of oxybenzoic acid, is preferably an anhydrous polar solvent that dissolves part or all of the p-oxybenzoic acid ester when heated.

Examples of polar solvents include methanol, ethanol, propatool, acetone, methyl ethyl ketone, acetonitrile, propionitrile, dimethyl sulfoxide, etc., and these can be used alone or in mixtures.

Among these solvents, methanol is the best.

Mixtures of methanol and the abovementioned solvents also show excellent effects.

The reaction temperature that can be used in the first stage reaction is preferably 100°C to 230°C, more preferably 120°C to 200°C.

Although the reaction time is determined by the reaction temperature, it is preferably within a range where the conversion rate of p-oxybenzoic acid ester is 35 to 85%.

The amount of alkali carbonate used in the first stage reaction is preferably 0.3 to 10 times the mole of p-oxybenzoic acid ester.
More preferably, it is 0.4 to 3 times the mole.

The amount of ethylene dichloride to be used is preferably 0.25 times or more, more preferably 0.5 to 2 times, by mole relative to the p-oxybenzoic acid ester.

The reaction mother liquor after the first stage reaction contains 2 to 5% by weight of produced water.
(0.0% per mole of charged p-oxybenzoic acid ester.
p-oxybenzoic acid ester, p-(2-chloroethoxy)benzoic acid ester and 4.4'-(ethylenedioxy)bisbenzoic acid ester have a boiling point The difference is large, and since it does not form an azeotropic mixture, it can be easily distilled off together with the polar solvent used and dissolved carbon dioxide gas by heating, and the active ingredient can be concentrated.

Dehydration and decarbonation of the reaction mother liquor can be carried out by heating at normal pressure or reduced pressure.

The water removal rate is desirably 50% or more of the amount produced, more desirably 80% or more.

Since the concentrate of the reaction mother liquor contains unreacted p-oxybenzoate ester and p-(2-chloroethoxy)benzoate ester, the subsequent reaction is basically an ether reaction of both in the presence of an alkali. p- reaction in the first stage reaction.
Depending on the charging composition of the oxybenzoate ester, ethylene dihalide, and alkali, or depending on the reaction conditions, the reaction can be carried out by adding p-oxybenzoate ester or ethylene dihalide as necessary.

The reaction temperature for the latter stage reaction is preferably 100 to 230°C, preferably 120 to 200°C.

The amount of alkali used in the subsequent reaction is determined by the amount of p present in the concentrate.
-The amount is preferably 0.5 times or more in mole relative to the oxybenzoic acid ester or intermediate, more preferably 0.5 to
It is twice the mole.

Examples and comparative examples are shown below.

Example 1 152 g of methyl p-oxybenzoate, 8.6 g of ethylene dichloride, 81 g of soda carbonate, 250 g of methanol
was placed in a No. 11 autoclave and heated at 165°C for 2 hours.

The reaction mixture was returned to room temperature, the reaction mixture containing crystals was separated by filtration, and the crystals were washed with 100 g of methanol.

The methanol washing solution was combined with the reaction mother liquor from which the crystals had been separated by filtration, and the mixture was heated at a maximum temperature of 130° C. under normal pressure to perform concentration dehydration and decarbonation.

The amount of water in the reaction solution before concentration was 0.42 mol, but after concentration it was 0.039 mol.

The concentrate contains 18.2% methyl p-oxybenzoate;
Methyl p-(2-chloroethoxy)benzoate is 16.3
% and 4. , 3.7% of methyl 4'-(ethylenedioxy)bisbenzoate was contained.

Next, the concentrate, 10.6 g of sodium carbonate, 5 g of ethylene dichloride, and 100 g of methanol were placed in a 500 cc autoclave and heated at 170° C. for 1.5 hours while stirring.

After the reaction was completed, the reaction mixture was separated by filtration, and the crystals were washed with 50 g of methanol and then recrystallized together with the crystals obtained in the previous reaction using 1500 g of toluene to obtain 125 g of white crystals.

This crystal was determined by infrared absorption spectrum and melting point measurement to be 4.4
It was confirmed that it was '-(ethylenedioxy)bisbenzoic acid ester.

Further, no by-product peak was observed by gas chromatography analysis.

The yield based on methyl p-oxybenzoate was 76%.

The acid value of this product was measured and was found to be 0.03 x 10-6 equivalent/g.

Comparative Example 152 g of methyl p-oxybenzoate, 81 g of ethylene dichloride, 81 g of soda carbonate, 200 g of methanol,
was placed in a 11 autoclave and heated at 165℃ under stirring for 3 hours.
heated for an hour.

After the reaction, the reaction mixture was separated by filtration, and the crystals were dissolved in toluene 12
After heating and dissolving using 00I, hot filtration and recrystallization, 4
．． 109 g (yield: 66) of 4'-(ethylenedioxy)bisbenzoic acid ester was obtained.

The acid value was measured and found to be 0.62 x 10-' equivalent/g.

After the crystals were filtered off, the reaction mother liquor contained 9.1% p-(2-hydroxyethoxy)bisbenzoic acid ester.

Example 2 152 g of methyl p-oxybenzoate, 10 g of potassium carbonate
5g, ethylene dichloride 86g, methanol 200g
g was placed in a No. 11 autoclave and heated at 165°C for 2 hours.

After the reaction, the crystals precipitated from the reaction solution were filtered, dissolved using 800 g of toluene, and recrystallized. 4.
Methyl 4'-(ethylenedioxy)bisbenzoate was obtained in a yield of 56%.

When the acid value of this product was measured, it was 0.04 x 10-6 equivalent/
It was g.

The reaction solution after filtering the crystals contained 0.38 mol of water.

This reaction solution was concentrated under reduced pressure at a temperature below 100°C, dehydrated and decarbonated, and then heated at 170°C for 1.5 hours with stirring in a 500cc autoclave with 13.8 g of potassium carbonate and 150 g of methanol. did.

After the reaction, the mixture was filtered and separated, and the crystals were recrystallized using 500 g of toluene.

Methyl 4.4'-(ethylenedioxy)bisbenzoate was obtained in a yield of 22%.

The acid value of this product was 0.02 x 10-6 equivalents/g.

Gas chromatography analysis showed that methyl p-(2-hydroxyethoxy)benzoate in the reaction mother liquor in the latter stage reaction was 5.8%.

Example 3 152 g of methyl p-oxybenzoate, 86 g of ethylene dichloride, 81 g of soda carbonate, 100 g of methanol,
Put 100g of acetonitrile into 11 autoclave,
The mixture was heated at 180° C. for 2 hours while stirring.

After the reaction, the reaction solution with precipitated crystals was separated by filtration, and the crystals were washed with methanol and recrystallized using 900 g of toluene, yielding methyl 4,4'-(ethylenedioxy)bisbenzoate. The yield was 55%.

The reaction mother liquor was combined with the methanol washing solution and concentrated under reduced pressure at below 100°C, and the water that was initially present at 0.35 mol was reduced to 0.0.
It became 19 moles.

The weight of the concentrate was 80g.

This concentrate contains 18.5 methyl p-oxybenzoate.
%, methyl p-(2-chloroethoxy)benzoate is 11
%, and 2.8% of 4,4'-(ethylenedioxy)bisbenzoic acid ester.

Next, concentrate, 15.9 g of soda carbonate, 8.0 g of ethylene dichloride, 80 g of methanol, 8 g of acetonitrile.
Put 0g into a 500CC autoclave and stir for 180℃.
Heated at <RTIgt;C</RTI> for 1.5 hours.

After the reaction, the reaction mixture in which crystals have precipitated is separated by filtration,
After washing the crystals with methanol, recrystallization was performed using 500 g of toluene.

37.3g of white crystals were obtained.

Results of infrared absorption spectrum analysis and touch point measurement, 4.4'-
It was confirmed that it was (ethylenedioxy)bisbenzoic acid ester, and as a result of gas chromatography analysis, no impurity peak was observed.

The yield is 26%.

The total yield of 4.4'-(ethylenedioxy)bisbenzoic acid ester is 81%.

When the acid value of the mixture of both was measured, it was 0.04 x 10-6.
equivalent/g.

p-(2-hydroxyethoxy) in the reaction solution of the later reaction
Methyl bisbenzoate was present at 47%.

Example 4 152 g of methyl p-oxybenzoate, 90 g of ethylene dichloride, 95 g of soda carbonate, 150 g of methanol
, 100 g of acetone was placed in a No. 11 autoclave and heated at 180° C. for 2 hours while stirring.

The reaction wave precipitated crystals were separated by filtration and washed with methanol.

When the methanol washing solution was combined with the reaction solution and subjected to concentration dehydration and decarboxylation at a temperature below 130°C under single pressure, the result was 0.04
The 7 moles of water became 0.022 moles.

This concentrate contains 13.3 methyl p-oxybenzoate.
%, methyl p-(2-chloroethoxy)benzoate is 13
．． It contained 4.4% of methyl 4.4'-(ethylenedioxy)bisbenzoate.

Next, 50 g of this concentrate, 0.12 mol of soda carbonate, 0.01 mol of ethylene dichloride, and 150 g of methanol were added.
The mixture was placed in a 0CC autoclave and heated at 180°C for 1 hour while stirring.

The crystals precipitated by the reaction wave are separated by filtration, washed with methanol, and combined with the crude crystals obtained in the previous reaction to 130% of toluene.
Recrystallization was performed using 0 g.

White methyl 4,4'-(ethylenedioxy)bisbenzoate was obtained in a yield of 83%.

The oxidation of this product was measured and found to be 0.041 x 10-6 equivalent/9.

The content of methyl p-(2-hydroxyethoxy)benzoate in the reaction mother liquor in the latter stage was 4.3%.

Claims (1)

[Claims] 1 Heat p-hydroxybenzoic acid ester and ethylene dichloride in the presence of an alkali carbonate and an anhydrous polar solvent until the conversion rate of p-oxybenzoic acid ester is 35 to 35.
The partially precipitated 4,4'-(ethylenedioxy)bisbenzoic acid ester and alkali halide were separated from the reaction solution obtained when the concentration reached 85%, and the mixture was further dehydrated and decarbonated by concentration. 4, characterized by heating again in the presence of an alkali carbonate and an anhydrous polar solvent.
, a method for producing 4'-(ethylenedioxy)bisbenzoic acid ester.