JPS585177B2 - 4,4'-(ethylenedioxy) bisanthocarboxylic acid ester - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention involves heating p-oxybenzoic acid ester and ethylene dichloride in the presence of an alkali carbonate.
This invention relates to a method for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester, characterized in that 5 mol% or more of calcium oxide is added in producing the -(ethylenedioxy)bisbenzoic acid ester. be.

Japanese Patent Publication No. 47-15338 and Japanese Patent Publication No. 47-27087 are known as conventional methods for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester using alkali carbonate as an alkali source, but Japanese Patent Publication No. 47-27089 In this method, the intermediate p-(2-chloroethoxy)benzoic acid ester must be recovered and recycled, which makes the equipment complicated and requires labor to prevent thermal decomposition or operational loss during recovery. There were drawbacks.

On the other hand, in the method of Japanese Patent Publication No. 47-15338, carbon dioxide gas produced as a by-product during the reaction accumulates as the reaction progresses, lowering the pH in the reaction system. Oxybenzoic acid ester alkali salt is difficult to form in the system, and the reaction rate becomes low.

However, water produced as a by-product during the reaction increases as the reaction progresses, and p-(2-hydroxyethoxy)benzoic acid ester, which is a hydrolyzate of esters and intermediates, is produced as a by-product.

Therefore, the yield was about 65-70%.

The present inventors conducted various studies on an industrially advantageous production method for 4.4'-(ethylenedioxy)bisbenzoate, and found that p-oxybenzoate and ethylene dichloride were combined in an anhydrous polar solvent. When producing the target product 4,4'=(ethylenedioxy)bisbenzoic acid ester by reacting with in the presence of an alkali carbonate,
Addition of calcium oxide has the effect of lowering the reaction pressure, increasing the rate of the desired reaction, suppressing the by-product of p-(2-hydroxyethoxy)benzoic acid ester, and improving the yield of the desired product. In addition, the content of impurities with free carboxylic acid groups (hereinafter abbreviated as acid value) contained in 4,4'-(ethylenedioxybisbenzoic acid ester) recrystallized with alkylbenzene such as toluene after the reaction. The present inventors have found that the amount is 0.05 x 10-6 equivalent/g or less, which is 1/10 or less compared to the case where calcium oxide is not added, and has completed the present invention.

That is, the method of the present invention involves heating and reacting p-oxybenzoic acid ester and ethylene dichloride in the presence of an alkali carbonate and an anhydrous polar solvent to produce 4,4'-(ethylenedioxy)bisbenzoic acid ester. This is a method for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester, which is characterized by adding calcium oxide.

The amount of calcium oxide added in the present invention is desirably 5 molar or more, more preferably 10 molar or more, based on the raw material p-oxybenzoic acid ester.

The method for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester in which calcium oxide is added according to the present invention has a yield of about 5 factors and a reaction pressure of 2 to 20% compared to the conventional method without adding calcium oxide.
There are effects such as a 3 kg/cri reduction and an acid value of 1/10 or less.

Details are shown in Examples and Comparative Examples.

Ethylene di to p-oxybenzoic acid ester with addition of calcium oxide according to the invention.

The ratio of chloride and alkali carbonate can be the same as in the conventional known method in which calcium oxide is not added, and the polar solvent used as the solvent can be a known polar solvent.

Furthermore, the reaction temperature and reaction time are also known. It is possible to use conditions of or milder conditions.

Examples and comparative examples are shown below.

Example 1 152 g of methyl p-oxybenzoate, ethylene.

Dichloride 86g, soda carbonate 81g, methanol 2
00g and 5.6g of calcium oxide were placed in a No. 11 autoclave and reacted at 165°C for 3 hours with stirring.

The reaction pressure was 32.5 kg/art. After the reaction, the precipitated crystals were filtered, heated and dissolved using 1,100° of toluene, and then filtered with heat to remove salt, and the crystals were precipitated at room temperature.

When this crystal was filtered and dried, it weighed 117 g, and as a result of gas chromatography analysis, no peak other than 4,4'-(ethylenedioxy)bisbenzoic acid dimethyl ester was observed.

The yield is 71%.

When the oxidation of this substance was measured, it was found to be 0.04 x 10-6 equivalent/
It was g.

The amount of p-(2-hydroxyethoxy)benzoic acid methyl ester produced in the reaction mother liquor after filtering off the crystals was '5.
It was 6%.

Comparative Example 152 g of methyl p-oxybenzoate, 86 g of ethylene dichloride, 81 g of sodium carbonate, and 200 p of methanol were placed in a 11 autoclave and reacted at 165° C. for 3 hours with stirring.

The reaction pressure was 34.0 kg/d.

After the reaction, the precipitated crystals were separated by filtration and recrystallized in the same manner as in Example 1. 4°4/-(ethylenedioxy)bisbenzoic acid dimethyl ester was obtained at 1:1 (yield: 66%).
)Obtained.

As a result of gas chromatography analysis, no by-product peaks were observed.

The acid value was measured and found to be 0.62 x 10-6 equivalent/g.

Further, the reaction mother liquor after the crystals were separated by furnace contained 9.1% p-(2-hydroxyethoxy)bisbenzoic acid ester.

Example 2 152 g of methyl p-oxybenzoate, 86 g of ethylene dichloride, 105 g of potassium carbonate, 250 g of methanol
g and 102 g of calcium oxide were placed in a No. 11 autoclave, and the reaction was carried out at 165° C. for 3 hours with stirring.

The reaction pressure was 31.9 kg/cm2. After the reaction, the precipitated crystals were filtered and recrystallized using 1200 g of toluene.

The amount of 4.4'(ethylenedioxy)bisbenzoic acid dimethyl ester obtained was 118 g.

Yield 71.5% The acid value of this product was measured and was 0.02.
x 10-6 equivalent/g.

Example 3 152 g of methyl p-oxybenzoate, 90 g of ethylene dichloride, 81 g of sodium carbonate, 250 g of methanol, and 10.2 g of calcium oxide were placed in a No. 11 autoclave and reacted at 165° C. for 3 hours with stirring.

The reaction pressure was 317 kg/cm2. After the reaction, the precipitated crystals were filtered and recrystallized using 1200 g of toluene.

The amount of 4,4'-(ethylenedioxy)bisbenzoic acid dimethyl ester obtained was 118 g.

Yield 71.5% The acid value of this product was measured and was 0.01.
X 10-' equivalent/g.

Furthermore, the amount of p-(2-hydroxyethoxy)benzoic acid methyl ester produced in the reaction mother liquor after filtering off the crystals was 5.
It was 9%.

Example 4 152 g of methyl p-oxybenzoate, 86 g of ethylene dichloride, 81 g of soda carbonate, 150 g of methanol,
100g of acetone and 10.2g of calcium oxide
1 and reacted at 180° C. for 2.5 hours with stirring.

After the reaction, filter the precipitated crystals and add toluene 1200
Hot filtration and recrystallization were performed using g.

120 g (yield 72.7%) of 4.4'-(ethylenedioxy)bisbenzoic acid dimethyl ester was obtained.

The acid value of this product was measured and was found to be 0.05 x 10-6 equivalent/g.

The amount of p-(2-hydroxyethoxy)benzoic acid methyl ester produced in the reaction mother liquor was 5.1%.

Claims (1)

[Claims] 1 Heating p-hydroxybenzoic acid ester and ethylene dichloride in the presence of alkali carbonate to give 4.4'
- A method for producing 4,4'-(ethylenedioxy)bisbenzoic acid ester, which comprises adding 5 mol% or more of calcium oxide in producing the (ethylenedioxy)bisbenzoic acid ester.