JPH0615502B2 - Method for producing acyloxy / naphthoic acid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing a corresponding acyloxynaphthoic acid compound by oxidizing an acyloxyalkylnaphthalene compound represented by the following general formula with molecular oxygen.

General formula; (In the formula; R ₁ is an alkyl group having 1 to 3 carbon atoms, R ₂ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) Specifically, from organic carboxylic acid or organic carboxylic acid and acetic anhydride as a solvent The present invention relates to a method for producing an acyloxy naphthoic acid, which comprises performing the oxidation reaction in the presence of a catalyst in which a bromine compound is added to at least one compound selected from the group consisting of cobalt and manganese compounds.

The acyloxynaphthoic acid compound obtained by the method of the present invention is a compound which is useful as a synthetic resin raw material or a synthetic fiber raw material as it is or in the form of a hydroxyl group obtained by hydrolyzing an acyloxy group.

[Conventional technology and its problems]

As a method for oxidizing an alkylbenzene having an acyloxy group in the presence of an oxidation catalyst, for example, Japanese Patent Publication No.
-849 and Japanese Patent Publication No. 50-35066. The former is a method of oxidizing p-cresyl acetate at 100 to 140 ° C. in the presence of a cobalt catalyst to obtain p-acetoxybenzoic acid. However, in this method, p-
The reaction rate of cresyl acetate is only 12 mol%. The latter invention is an improvement of the former and is a method of using an organic carboxylic acid or its anhydride as a solvent and a ternary system of a bromine compound, a cobalt compound and a manganese compound as a catalyst.

It is also known to oxidize an alkylnaphthalene compound such as methylnaphthalene or dimethylnaphthalene with molecular oxygen in the presence of a heavy metal catalyst to obtain naphthoic acid or naphthalenedicarboxylic acid.

Further, the present applicant has previously proposed that an alkylnaphthalene compound having an acyloxy group obtained by reacting an acylalkylnaphthalene compound with a peroxide in an organic catalyst in a bromine compound-
Cobalt compound or bromine compound-Cobalt compound-
We have developed a method for producing acyloxy / naphthoic acid compounds that oxidize with molecular oxygen in the presence of manganese compounds. (Japanese Patent Application Nos. 59-145183 and 59-163402) This method efficiently gives the corresponding acyloxy naphthoic acid, but the reaction rate of the acyloxy alkylnaphthalene is still insufficient.

[Means for solving problems]

Therefore, as a result of various studies to enhance the reaction rate of acyloxy alkylnaphthalene, an acyloxy compound obtained by reacting an acylnaphthalene compound with a peroxide such as hydrogen peroxide in a solvent containing a specific amount of formic acid and water. By using an alkylnaphthalene compound as a raw material for the oxidation reaction, the reaction rate of acyloxy alkylnaphthalene was improved, and it was found that acyloxy naphthoic acid can be obtained in a high yield, and the present invention was accomplished.

That is, the present invention is represented by the following general formula (1) (wherein R ₁ is a carbon number 1 to
3 alkyl group, R ₂ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms. ) When an acyloxynaphthalene compound is oxidized with molecular oxygen in the presence of at least one compound of cobalt or manganese compounds and a bromine compound in an organic solvent, an acylalkylnaphthalene represented by the following general formula (2) (In the formula, R ₁ and R ₂ are the same as above) The compound is hydrogen peroxide or an organic peracid or a mixture thereof in the presence of a solvent having a formic acid concentration of 45 to 95% by weight and a water concentration of at least 5% by weight. The method for producing an acyloxy naphthoic acid is characterized by using an acyloxy alkylnaphthalene compound represented by the general formula (1) obtained by oxidation with one of the above.

The acyloxy / alkylnaphthalene compound used in the present invention can be obtained by reacting an acyl / alkylnaphthalene with a peroxide such as hydrogen peroxide. The reaction temperature at this time is 0 ° C to 100 ° C. Yes, but usually 1
It is performed in the range of 0 ° C to 70 ° C.

The reaction is carried out in a solvent containing a specific amount of formic acid and water, and the amount of formic acid to be used can be usually in the range of 0.1 to 100 by weight ratio with respect to the raw material acyl alkylnaphthalene compound. Is suitably 0.3 to 30.

Further, in the reaction, formic acid and water itself function as a reaction solvent, so that other reaction solvent is not particularly required,
Any solvent can be used as long as it does not adversely affect the reaction.

Examples of such a solvent include organic fatty acids, their esters, and aromatic hydrocarbons.

The organic fatty acid is a lower fatty acid having 2 to 4 carbon atoms, and examples thereof include acetic acid, propionic acid and butyric acid.
Examples of the organic fatty acid ester include methyl formate, ethyl formate, methyl acetate, ethyl acetate, methyl propionate, ethyl propionate, and the like. Further, as the aromatic hydrocarbon, benzene, toluene, xylene,
Such as ethylbenzene.

Hydrogen peroxide or one of organic peracids or mixtures thereof is used in the reaction. Industrially, it is preferable to use hydrogen peroxide. The organic peracid is a percarboxylic acid synthesized from hydrogen peroxide and a lower fatty acid, and examples thereof include peracetic acid and perpropionic acid.

In the reaction, hydrogen peroxide can be supplied as it is or as a formic acid solution or as an organic fatty acid solution used as another solvent. A hydrogen peroxide solution of formic acid or an organic fatty acid solution may generate a part of percarboxylic acid when the residence time is long, but it can be used without any trouble. Hydrogen peroxide having a concentration of 30 to 95 wt% is usually used.

Hydrogen peroxide is used in a molar ratio of 1.00 to 2.0 with respect to the raw material acyl alkylnaphthalene. Use beyond this range has no particular advantage, and in some cases may lead to disadvantages with side reactions.

In the reaction, organic peracids such as pastic acid and perpropionic acid are used as well as hydrogen peroxide.

After completion of the reaction, the reaction product is cooled to precipitate crystals,
Crystals of acyloxy alkylnaphthalene are obtained. If necessary, the crystals are rinsed with the same solvent as used in the reaction.

Specific examples of the acyloxy alkylnaphthalene compound represented by the general formula (1) obtained as described above include 2-methyl-6-acetyloxynaphthalene, 2-methyl-6-propyloxynaphthalene, 2-
Methyl-6-isobutyryloxynaphthalene, 2-methyl-7-acetyloxynaphthalene, 2-methyl-7-
Propionyloxynaphthalene, 2-methyl-7-isobutyryloxynaphthalene, 2-ethyl-6-acetyloxynaphthalene, 2-ethyl-6-propynyloxynaphthalene, 2-ethyl-6-isobutyryloxynaphthalene, 2- Ethyl-7-acetyloxynaphthalene,
2-ethyl-7-propionyloxynaphthalene, 2-
Ethyl-7-isobutyryloxynaphthalene, 2-isopropyl-6-acetyloxynaphthalene, 2-isopropyl-6-propionyloxynaphthalene, 2-isopropyl-6-isobutyryloxynaphthalene, 2-isopropyl-7-acetyloxy Naphthalene, 2-isopropyl-7-propionyloxynaphthalene, 2-isopropyl-7-isobutyryloxynaphthalene, 1-
Methyl-6-acetyloxynaphthalene, 1-methyl-
6-propionyloxynaphthalene, 1-methyl-6-
Examples include isobutyryloxynaphthalene, 1-methyl-7-acetyloxynaphthalene, 1-methyl-7-propionyloxynaphthalene and 1-methyl-7-isobutyryloxynaphthalene.

Next, the oxidation reaction of the acyloxy alkylnaphthalene compound obtained by the reaction with molecular oxygen is carried out in the presence of an organic solvent.

As the solvent used in the oxidation reaction, a lower organic carboxylic acid having 2 to 4 carbon atoms or a mixture of the organic carboxylic acid and acetic anhydride is used.

The amount of the solvent used is at least twice or more, preferably 3 to 100 times the amount of the reaction raw material.

The water content in the reaction solvent is preferably as low as possible. Although it varies depending on the catalyst concentration, the amount of the solvent used with respect to the reaction raw material, etc., it may be one that can be usually supplied industrially, and is generally 1 wt% or less, preferably 0.5 wt% or less.
If the amount of water is too large, the reaction due to molecular oxygen is not started, or even if the reaction is started, side reactions such as hydrolysis reaction occur, which is not preferable.

When a mixture of organic carboxylic acid and acetic anhydride is used, acetic anhydride is preferably 100 times mol or less, preferably 30 times mol or less with respect to the reaction raw material.

If the amount of acetic anhydride is too large, the selectivity of acyloxy / naphthoic acid is likely to decrease, which is not preferable.

Next, the catalyst used in the present invention is a binary system consisting of a bromine compound and a cobalt compound or a ternary system in which a manganese compound is further added to the catalyst. Examples of the bromine compound include cobalt bromide and hydrobromic acid. , Sodium bromide, manganese bromide or ammonium bromide are used, and the amount used is 100 wtppm as Br against the solvent.
As described above, it is preferably 200 to 10,000 wtppm.

Examples of the cobalt compound include cobalt bromide and cobalt acetate, and the amount used is 1 as Co with respect to the solvent.
It is 0 wtppm or more, preferably 50 to 5000 wtppm. Further, the manganese compound is exemplified by manganese bromide, manganese acetate and the like, and is used at a concentration of 5000 wtppm or less as Mn in the solvent.

In the present invention, the reaction temperature is preferably in the range of 100 to 200 ° C. If the temperature is too high, the naphthalene nucleus is decomposed, which is not preferable, and if the temperature is lower than 100 ° C, the reaction does not proceed sufficiently, which is not preferable.

The reaction pressure is atmospheric pressure to 200 kg / cm ² G, oxygen partial pressure 4
0 kg / cm ² G or less is adopted, and it is not preferable if the oxygen partial pressure is zero, but the reaction proceeds sufficiently even if the oxygen partial pressure is 2 kg / cm ² G or less. The molecular oxygen of the present invention is an oxygen-containing gas diluted with pure oxygen gas or an inert gas, for example, air,
Either can be used.

〔The invention's effect〕

According to the present invention, a naphthoic acid compound having an acyloxy group can be easily obtained in high yield with high selectivity. The naphthoic acid compound is used as it is or as a hydroxyl group by hydrolyzing an acyloxy group, and is used as a raw material compound of a synthetic resin or a synthetic fiber. The naphthoic acid compound obtained by the method of the present invention, such as 6-acetyloxy-2-naphthoic acid, has recently attracted attention as a high-strength polyester fiber raw material, and the present invention industrially supplies such naphthoic acid. It is possible and extremely significant.

〔Example〕

 Next, examples of the present invention will be described.

Example 1 12.4 g of water, 40 g of formic acid and 2-methyl-6 were placed in a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel.
-Add 29.2 g of acetylnaphthalene and keep at 29 ° C on a water bath while stirring.

A mixture 49.8 prepared beforehand with 30.12 g of formic acid, 10.04 g of water and 9.64 g of 90% aqueous hydrogen peroxide solution.
g is added dropwise from the dropping funnel over 3 minutes with stirring.
(Concentration of formic acid 74.7 wt%) Although heat generation is observed with the dropping, water cooling is performed as necessary to maintain the liquid temperature at 29 ° C. After the dropping was completed, the reaction was carried out at 29 ° C for about 5 hours.

After completion of the reaction, 2-methyl-of the desired product is obtained from the reaction mixture.
Crystals of 6-acetyloxynaphthalene were separated, rinsed with an aqueous solution of formic acid, and dried under reduced pressure at 60 ° C.

Then 2-methyl-6-acetyloxynaphthalene 5.
5g, acetic acid (water content 0.2wt%) 100g, acetic anhydride 1
0 g, cobalt acetate tetrahydrate, 1.16 g (cobalt 25
00wtppm) Manganese acetate tetrahydrate 1.23g (manganese 2500wtppm) and ammonium bromide 0.384g (bromine 2850wtppm) were charged into a titanium autoclave equipped with a stirrer and having an internal volume of 500m, and 2,3-3.0kg /
After pressurizing to cm ² G with air, it is heated to 117 to 123 ° C.

Air was passed at a rate of 30 / hr, and the reaction was continued until there was no oxygen absorption. The reaction time was 1 hour.

The contents were taken out and analyzed by high performance liquid chromatography. As a result, the conversion of 2-methyl-6-acetyloxynaphthalene was 97.2%, and the yield of 6-acetyloxy-2-naphthoic acid was 88.8 mol% (selectivity. 91.3 mol%)
Met.

Example 2 1.14 g of water, 11.46 g of formic acid and 8.58 g of 2-methyl-6-acetylnaphthalene were added to a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel, and stirred on a water bath for 20 times. Hold at ° C.

10 g of formic acid, 2.64 g of 90% hydrogen peroxide solution in advance
12.64 g of a mixture prepared by mixing
It takes a minute to add dropwise under stirring. (Formic acid concentration 93.9 wt
%) Exothermic heat is observed with dropping, but if necessary, cool with water to maintain the liquid temperature at 17 to 20 ° C. 17-23 ° C after dropping
And reacted for about 5 hours.

After completion of the reaction, 2-methyl-of the desired product is obtained from the reaction mixture.
Crystals of 6-acetyloxynaphthalene were separated, rinsed with an aqueous solution of formic acid, and dried under reduced pressure at 60 ° C.

Then, 5.5 g of 2-methyl-6-acetyloxynaphthalene, 100 g of acetic acid (water content 0.2 wt%), 10 g of acetic anhydride, 0.047 g of cobalt acetate tetrahydrate (cobalt 100 wtppm), manganese acetate tetrahydrate 0.1 g. 442g (manganese 900wtppm), ammonium bromide 0.384g
(Bromine 2850wtppm) was charged into a titanium autoclave equipped with a stirrer with an internal volume of 50m, and 1.7 to 2.2kg.
After pressurizing with air / cm ² G with air, it is heated to 118 to 124 ° C.

Air was passed at a rate of 27 / hr and the reaction was continued until there was no absorption of oxygen. The reaction time was 1 hour.

The contents were taken out and analyzed by high performance liquid chromatography. As a result, the conversion of 2-methyl-6-acetyloxynaphthalene was 96.2%, and the yield of 6-acetyloxy-2-naphthoic acid was 80.3 mol% (selectivity. 83.4 mol%)
Met.

Example 3 14.64 g of water, 22.28 g of formic acid and 7.86 g of 2-methyl-6-acetylnaphthalene were added to a reaction vessel equipped with a stirrer, a reflux condenser, and a dropping funnel, and 40 on a water bath while stirring. Hold at ° C.

14.77 g of a mixture prepared in advance with 7.31 g of formic acid, 5.0 g of water and 2.46 g of 90% aqueous hydrogen peroxide solution is added dropwise under stirring over 30 minutes from a dropping funnel.
(Concentration of formic acid 59.8 wt%) Although heat generation is observed with dropping, water cooling is performed as necessary to maintain the liquid temperature at 40 ° C. After the dropping was completed, the reaction was carried out at 40 ° C for about 5 hours.

After completion of the reaction, 2-methyl-of the desired product is obtained from the reaction mixture.
Crystals of 6-acetyloxynaphthalene were separated, rinsed with an aqueous solution of formic acid, and dried under reduced pressure at 60 ° C.

Then 2-methyl-6-acetyloxynaphthalene 5.
5g, acetic acid (water content 0.2wt%) 100g, acetic anhydride 1
0 g, 0.34 g of cobalt acetate tetrahydrate (cobalt 75
0 wtppm), manganese acetate tetrahydrate 0.123 g (manganese 250 wtppm), ammonium bromide 0.384 g (bromine 2850 wtppm) were charged into a titanium autoclave with an internal volume of 500 m and equipped with a stirrer, 1.7 to 2.1 kg /
After pressurizing the cm ² G with air, it is heated to 118 to 123 ° C.

Air was passed at a rate of 40 / hr, and the reaction was continued until there was no absorption of oxygen. The reaction time was 1 hour.

The contents were taken out and analyzed by high performance liquid chromatography. As a result, the conversion of 2-methyl-6-acetyloxynaphthalene was 100% and the yield of 6-acetyloxy-2-naphthoic acid was 86.0 mol% (selectivity 86. 0 mol%).

The selectivity of 6-hydroxy-2-naphthoic acid is 0.5.
It was mol%.

Example 4 5.04 g of ethyl acetate and 7.39 g of 2-methyl-6-acetylnaphthalene were added to a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel, and the mixture was kept at 30 ° C on a water bath while stirring. .

7.8 g of a mixture prepared in advance with 5.03 g of formic acid, 0.5 g of water and 2.27 g of 90% aqueous hydrogen peroxide is added dropwise from a dropping funnel over 19 minutes with stirring. (Concentration of formic acid 46.6 wt%) Although heat generation is observed with dropping, water cooling is performed as necessary to maintain the liquid temperature at 30 ° C. After completion of dropping, the reaction was carried out at 30 ° C for about 10 hours.

After completion of the reaction, 2-methyl-of the desired product is obtained from the reaction mixture.
Crystals of 6-acetyloxynaphthalene were separated, rinsed with an aqueous solution of formic acid, and dried under reduced pressure at 60 ° C.

Then 2-methyl-6-acetyloxynaphthalene 5.
5g, acetic acid (water content 0.2wt%) 100g, acetic anhydride 1
0 g, 0.244 g of cobalt acetate tetrahydrate (cobalt 52
5 wtppm), manganese acetate tetrahydrate 0.244 g (manganese 500 wtppm), ammonium bromide 0.384 g (bromine 2850 wtppm) were charged into a titanium autoclave equipped with a stirrer and having an internal volume of 500 m, and 2 kg / cm ² G was aired. After pressurizing, heat to 115-116 ° C.

Air was passed at a rate of 71 / hr and the reaction was continued until there was no absorption of oxygen. The reaction time was 2 hours.

The contents were taken out and analyzed by high performance liquid chromatography. As a result, the conversion of 2-methyl-6-acetyloxynaphthalene was 100%, and the yield of 6-acetyloxy-2-naphthoic acid was 88.2 mol% (selectivity 88. 2 mol%).

Examples 5 to 10 The reaction was carried out under the same conditions as in the previous-stage reaction of Example 1, and the obtained 2-methyl-6-acetyloxynaphthalene was used in the same manner as in Example 1 under the conditions shown in Table-1. Was carried out.

The obtained results are shown in Table-1.

The water concentration in the reaction solvent before the reaction in Example 8 was about 0.2 wt%.

Example 11 In a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel, 3.1 g of water, 10 g of formic acid and 2-methyl-6-
Add 12.1 g of isobutyryl naphthalene and keep at 29 ° C on a water bath while stirring.

A mixture 12.45 prepared by preliminarily preparing 7.53 g of formic acid, 2.51 g of water and 2.41 g of a 90% aqueous hydrogen peroxide solution.
g is added dropwise from the dropping funnel over 3 minutes with stirring.
(Concentration of formic acid 74.7 wt%) Although heat generation is observed with the dropping, water cooling is performed as necessary to maintain the liquid temperature at 29 ° C. After the dropping was completed, the reaction was carried out at 29 ° C for about 5 hours.

After completion of the reaction, 2-methyl-of the desired product is obtained from the reaction mixture.
Crystals of 6-isobutyloxynaphthalene were separated, rinsed with an aqueous solution of formic acid, and dried under reduced pressure at 60 ° C.

Next, 10 g of 2-methyl-6-isobutyryloxynaphthalene, 100 g of acetic acid (water content 0.2 wt%), 10 g of acetic anhydride, and 0.244 g of cobalt acetate tetrahydrate (cobalt 5
25 wtppm), manganese acetate tetrahydrate 0.244 g (manganese 500 wtppm), ammonium bromide 0.384 g
(Bromine 2850 wtppm) is charged into a titanium autoclave with an internal volume of 500 ml and equipped with a stirrer, pressurized to 25 kg / cm ² G with air, and then heated to 120 ° C.

Air was passed at a rate of 25 / hr, and the reaction was continued until there was no oxygen absorption. The reaction time was 2.5 hours.

The contents were taken out and analyzed by high performance liquid chromatography. As a result, the conversion rate of 2-methyl-6-isobutyryloxynaphthalene was 100%, and 6-isobutyryloxy-2 was used.
-The yield of naphthoic acid is 78.5 mol% (selectivity 78.5 m
ol%).

Example 12 In a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel, 3.1 g of water, 10 g of formic acid and 2-ethyl-6-
Add 10.6 g of acetylnaphthalene and keep at 29 ° C on a water bath while stirring.

12.45 g of a mixture prepared in advance with 7.53 g of formic acid, 2.51 g of water and 2.41 g of a 90% aqueous hydrogen peroxide solution.
Is added under stirring over 3 minutes from the dropping funnel.
(Concentration of formic acid 74.7 wt%) Although heat generation is observed with the dropping, water cooling is performed as necessary to maintain the liquid temperature at 29 ° C. After the dropping was completed, the reaction was carried out at 29 ° C for about 5 hours.

After completion of the reaction, 2-ethyl-of the desired product is obtained from the reaction mixture.
Crystals of 6-acetyloxynaphthalene were separated, rinsed with an aqueous solution of formic acid, and dried under reduced pressure at 60 ° C.

Then 10 g of 2-ethyl-6-acetoxynaphthalene,
Acetic acid (water content 0.2 wt%) 100 g, acetic anhydride 10 g,
Cobalt acetate tetrahydrate 0.244 g (cobalt 525 wt p
pm), manganese acetate tetrahydrate 0.244 g (manganese 5
00 wt ppm), ammonium bromide 0.384 g (bromine 2
850 wtppm) was charged into a titanium autoclave with an internal volume of 500 ml equipped with a stirrer, pressurized to 25 kg / cm ² G with air, and then heated to 120 ° C.

Air was passed at a rate of 25 / hr, and the reaction was continued until there was no oxygen absorption. The reaction time was 2.5 hours.

The contents were taken out and analyzed by high performance liquid chromatography. As a result, the conversion of 2-ethyl-6-acetyloxynaphthalene was 100% and the yield of 6-acetyloxy-2-naphthoic acid was 76.3 mol% (selectivity: 76. 3 mol%).

Claims (1)

[Claims] 1. An acyloxy alkylnaphthalene compound represented by the general formula (1) (In the formula; R ₁ is an alkyl group having 1 to 3 carbon atoms, R ₂ is a hydrogen atom or an alkyl group having 1 to 4 carbon atoms.) At least one compound of cobalt or manganese compounds in an organic solvent and a bromine compound In the presence of, when oxidized by molecular oxygen, the acyl alkylnaphthalene represented by the following general formula (2) (Wherein R ₁ and R ₂ are the same as above) In the presence of a solvent having a formic acid concentration of 45 to 95% by weight and a water concentration of at least 5% by weight, hydrogen peroxide or an organic peracid or a mixture thereof is added. A method for producing an acyloxy naphthoic acid, characterized by using an acyloxy alkylnaphthalene compound represented by the general formula (1) obtained by oxidation with one kind