JPS61204152A - Production method of acyloxynaphthalene and its derivatives - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION C. Industrial Application Field of the Invention The present invention relates to a method for producing acyloxynaphthalenes and derivatives thereof by oxidizing acylnaphthalenes with hydrogen peroxide or organic peracids or mixtures thereof. The acyloxynaphthalenes obtained by the method of the present invention can be used as they are as additives such as plasticizers, but they can be easily converted into naphthols by hydrolysis. These naphthols are useful substances as intermediates or raw materials for medicines, good medicines, dyes, etc., or as raw materials for plastics.

The present invention provides a method for industrially and efficiently producing such useful substances.

[Prior art and its problems]

Conventionally, general methods for producing naphthols include separation from tar acid, sulfonation of a 7-talene nucleus, and alkali melting.

However, in the former case, it is difficult to purify to a high purity product K because the raw material is a mixture of 7-tols with small differences in physical properties not only between isomers but also between homologues, and in the latter case, it is difficult to purify the product to a high purity product K. This method has drawbacks such as not necessarily high selectivity (not necessarily high selectivity) and the need for waste treatment. Even if 7-tolls are obtained, this method must be further processed to obtain acyloxy compounds. Must be treated with acid or organic acid anhydride.

On the other hand, the method of synthesizing phenylformate derivatives by oxidizing aromatic aldehyde fragments with hydrogen peroxide or organic peracids is well known as the Bayer-Villiger reaction. This method is characterized by the fact that it provides products with high isomer purity, and has recently attracted attention as it has become possible to industrially produce aromatic aldehydes by carbonylating aromatic hydrocarbon compounds. There is.

The applicant has previously disclosed that acyloxynaphthalenes are produced by oxidizing acylnaphthalenes with hydrogen peroxide or an organic peracid or one of the mixtures thereof in the presence of an organic fatty acid or a mixture of an organic fatty acid and an organic fatty acid ester or an aromatic hydrocarbon. and a method for producing its derivatives was developed and filed (Japanese Patent Application No. 59-140140). This method is effective as an industrially advantageous method for producing acyloxynaphthalene and its derivatives without using means such as sulfonation of the naphthalene nucleus or alkali melting, but the reaction rate of acylnaphthalene is still insufficient. .

[Means for solving problems]

Therefore, as a result of repeated studies to increase the reaction rate of acylnaphthalenes, we found that when reacting acylnaphthalenes with peroxides such as hydrogen peroxide, by reacting them in a solvent containing specific amounts of formic acid and water. It was found that acyloxynaphthalene can be obtained at a high reaction rate, leading to the present invention.

That is, the present invention relates to the following general formula (I) [wherein R1 represents an alkyl group having 1 to 4 carbon atoms, R2 represents a hydrogen atom or an alkyl group or an alkoxy group having 1 to 10 carbon atoms,
n=1 to 4. ] The present invention relates to a method for producing acyloxynaphthalenes and derivatives thereof, characterized in that acylnaphthalenes represented by the following are oxidized with an organic peracid having a formic acid concentration or a mixture thereof.

The acylnaphthalenes represented by the above general formula 1 in the present invention 2 do not have an electron-donating group such as an alkyl group or an alkoxy group in the same ring where an acyl group is present, and, for example, in the presence of a catalyst. The following can be easily obtained by acetylation of 2-methylnaphthalene. Specifically, the acylnaphthalenes represented by the above general formula (I) include acetylnaphthalene, 2-methyl-6-acetylnaphthalene, 1,3-dimethyl-6-acetylnaphthalene, and 2-ethyl-6-acetylnaphthalene. , 1,4-
Dimethyl-6-acetylnaphthalene, 2-methyl-5-
Acetylnaphthalene, 1,2.4-)samethyl-5-acetylnaphthalene, 2-methyl-6-propionylnaphthalene, 2-methyl-6-butyryluna7talene, 2
-Methyl-6-neopentylnaphthalene etc. are exemplified,
Among these, K is 2-methyl-6-acetylnaphthalene, 2-ethyl-
6-acetylnaphthalene, 1,5-dimethyl-6-acetylnaphthalene, 2-methyl-6-propionylnaphthalene, 2-methyl-6-butyrilunaphthalene, 2-
Preferred raw materials include methyl-6-neopentylnaphthalene.

The method of the present invention is carried out in a solvent containing specific amounts of formic acid and water, and the concentration of formic acid in the solvent [formic acid/(formic acid + water + solvent) x loo] is 45 to 95% by weight, Preferably it is 60 to 95% by weight. When the formic acid concentration is lower than 45% by weight, the reaction rate of two people is slow and a high reaction rate cannot be obtained.

On the other hand, a higher concentration of formic acid gives better results, but 95
If the concentration is higher than % by weight, not only will a high reaction rate not be obtained, but also by-products will increase, which is undesirable. In addition, the concentration of water [water/(formic acid + water + solvent) x 100] is
Although K is required to be present in an amount of at least 5% by weight in order to obtain a high reaction rate, it is not preferable to have too much K, and the amount is usually 6 to 45% by weight, depending on other reaction conditions such as reaction temperature. Industrially, it is preferable to have an azeotropic composition of formic acid and water, and 20 to 40% by weight is appropriate.

The concentration of formic acid is within the above range, but the amount of formic acid used is usually 0.1 to 0.1 to 0.1 to the weight ratio of the raw material acylnaphthalenes.
It can be used in the range of 100, but if it is less than 0.1, the reaction will not be carried out smoothly and sufficiently, which is not preferred.

On the other hand, if the amount is as large as over 100, there is no particular disadvantage in one reaction itself, but it is not preferred from an economic point of view. Therefore, the appropriate amount of formic acid to be used is 0.3 to 30 in terms of weight ratio.

In the method of the present invention, formic acid and water themselves function as solvents, so no other solvent is particularly required, but any other solvent can be used as long as it does not have a negative effect on the reaction. . Examples of such solvents include organic fatty acids and their esters, and aromatic hydrocarbons.

The organic fatty acids are lower fatty acids having 2 to 4 carbon atoms, such as acetic acid, propionic acid, and butyric acid. Examples of organic fatty acid esters include methyl formate, ethyl formate, methyl acetate, ethyl acetate, methyl propionate, and ethyl propionate. Examples of aromatic hydrocarbons include benzene, toluene, xylene, and ethylbenzene. In the present invention, one of hydrogen peroxide, an organic peracid, or a mixture thereof is used. Industrially, it is preferable to use hydrogen peroxide. Organic peracids are synthesized from hydrogen peroxide and lower fatty acids, such as percarboxylic acid, peracetic acid, and perpropionic acid.

For example,

It can be used in the reaction as an organic fatty acid solvent used as another solvent. A solution of hydrogen peroxide in formic acid or an organic fatty acid solution may produce some percarboxylic acid if the residence time is long, but it can be used without any problem.

Hydrogen peroxide is usually used at a concentration of 30 to 95 wt%.

The molar ratio of hydrogen peroxide to the raw material acylnaphthalenes is 1. It is used in the range of On to 2.0. If the amount exceeds this range, there is no particular advantage, and in some cases, side reactions may occur, resulting in disadvantages.

In the present invention, organic peracids such as peracid and perpropionic acid are also used in the same manner as hydrogen peroxide.

The reaction of the present invention can be carried out at a temperature ranging from 0°C to 100°C, but is usually carried out at a temperature ranging from 1'0°C to 70°C, preferably from 15°C to 60°C.

When the reaction temperature is lower than 10°C, the reaction rate is slow and it is not practical (on the other hand, when it exceeds 70°C, the selectivity of the reaction decreases, which is disadvantageous. It is not preferable to carry out the reaction at a high temperature. Therefore, when the reaction is carried out at a high temperature of 60° C. or higher, it is preferable to raise the temperature stepwise.

The method of the present invention is a reaction accompanied by heat generation, and in order to maintain the reaction temperature within the above range during the reaction, consideration must be given to heat removal that can cope with the reaction heat. Mask heat removal methods using internal or external heat exchangers are usually suitable for this purpose.

When carried out industrially, under reduced or increased reaction pressure,
It is preferable to carry out the reaction under conditions that allow the solvent to boil at a predetermined reaction temperature, and the heat can be removed by absorption of latent heat accompanying evaporation of solvent vapor.

The reaction mixture obtained by the reaction mainly consists of acyloxynaphthalene corresponding to the raw material acylnaphthalene, a reaction solvent, and water, and also contains a small amount of high-boiling components as by-products. The desired product can be obtained from this mixture by removing the solvent and water and separating the high-boiling components. Further, after the oxidation reaction is completed, the reaction mixture can be directly hydrolyzed by a conventional method to obtain naphthols from K. Industrially, unless acyloxynaphthalene is particularly required, after the oxidation reaction is completed, hydrolysis is usually carried out to produce the corresponding naphthols.

Incidentally, the separated water-containing solvent can be used again after being purified by a known method.

〔Effect of the invention〕

According to the present invention, acyloxynaphthalenes and their derivatives, which have conventionally been difficult to produce industrially, and 7-tolls can be easily produced without going through complicated methods such as sulfonation and alkali melting. It can be produced with high yield and high purity.

〔Example〕

Examples of the present invention are shown below.

Example 1 Water in a reaction vessel equipped with a stirrer, reflux condenser and dropping funnel 3.15. Formic acid 1011 and 2-methyl-
Add 7.3 g of 6-acetylnaphthalene and maintain at 29°C on a water bath while stirring.

Formic acid 7.551. A mixture of water 2.51 & 90% hydrogen peroxide 2.41 J/12.4
59 was added dropwise from the dropping funnel over a period of 6 minutes while stirring (
Formic acid concentration: 74.7 wt%)a Heat generation is observed as the solution is added, but if necessary, cool with water to maintain the liquid temperature at 29°C.

After the dropwise addition was completed, the reaction was carried out at 29°C for about 5 hours.

After the completion of the reaction, the target product was separated from the reactor mixture, and the product was analyzed by gas chromatography. As a result, 2
-Reaction rate of methyl-6-acetylnaphthalene 94.4
%, the selectivity of 2-methyl-6-acetyloxynaphthalene was 93.4%.

Example 2 Water was added to a reactor equipped with a reflux condenser and a dropping funnel.
7, 6, 9. Formic acid 165.1/and 2-methyl-6-
Add acetylnaphthalene 12°55.9 and keep at 26-27°C on a water bath.

This charge liquid was taken out from the reactor using an external circulation pump, and circulated through the cooler into the reactor at a rate of 101/min.
0% hydrogen peroxide 3.86. ! A mixture prepared with IT was added dropwise from the dropping funnel over a period of 12 minutes.

After the completion of the dropwise addition, the reaction was continued for 6 hours at a temperature of 28 to 60°C while circulating at a rate of 101/min.

After the reaction was completed, the desired product was separated from the reaction mixture, and the product was analyzed by gas chromatography. As a result, 2
-Reaction rate of methyl-6-acetylnaphthalene 88.2
%, the selectivity of 2-methyl-6-acetyloxynaphthalene was 99.6%.

Examples 3 to 8 Examples 6 to 8 were carried out in the same manner as in Example 1 under the conditions shown in Table IK.

The results obtained are shown in Table-1.

Example 9 2.5y of formic acid and 7.33ml of 2-methyl-6-acetylnaphthalene are added to a reaction vessel equipped with a stirrer, a reflux condenser, and a dropping funnel, and maintained at 30°C on a water bath while stirring.

In advance, formic acid 2.5g, water 1.41.9 and 90% hydrogen peroxide 2.32j! A mixture prepared by 6.25
fl is added dropwise from the dropping funnel while stirring over a period of about 60 minutes (formic acid concentration 75.3 wt%). Heat generation is observed during the dropping, but cool with water as necessary to bring the liquid temperature to 30-31°C. Hold.

After the completion of the dropwise addition, the temperature was maintained at 30℃ for 60 minutes, and then the liquid temperature was increased to 35℃.
After raising the temperature to 40°C and reacting for 1 hour, the temperature was raised to 50°C and reacted for 50 minutes, and finally the temperature was raised to 55°C and reacted for 60 minutes.

After the reaction was completed, the desired product was separated from the reaction mixture, and the product was analyzed by gas chromatography. As a result, 2
-Reaction rate of methyl-6-acetylnaphthalene 87#5
%, the selectivity of 2-methyl-6-acetyloxynaphthalene was 91.8%.

Example 10 To a reaction vessel equipped with a stirrer, a reflux condenser and a dropping funnel are added 5.02S of formic acid and 7.3S of 2-methyl-6-acetylnaphthalene and maintained at 30"C on a water bath while stirring.

Mixture 10.15.9 prepared in advance with 5 I of formic acid, 183 J of water, and 2.32 J of 90% hydrogen peroxide is added dropwise from the dropping funnel with stirring over a period of about 70 minutes (formic acid concentration: 76, 6 wt%).

Heat generation is observed as the mixture is dropped, but if necessary, cool with water to maintain the liquid temperature at 30°C.

50 minutes after the completion of dropping, the liquid temperature was kept at 30℃, and then the temperature was increased to 35"
Raise the CK and let it react for 1 hour, then raise the liquid temperature to 40℃ 1
After reacting for an hour, the liquid temperature was raised to 45°C, and the reaction was continued for 50 minutes.The final KfL temperature was then raised to 50°C, and the reaction was continued for 30 minutes.

The target product was separated from the reaction mixture and analyzed by gas chromatography. As a result, 2-methyl-6
-Acetylnaphthalene reaction rate 93%, 2-methyl-
The selectivity of 6-acetyloxynaphthalene was 92.7%.

Example 11 In a reaction vessel equipped with a stirrer, a reflux condenser, and a dropping funnel, 7.5y of formic acid and 7.33. Add p and keep at 29°C on a water bath with stirring.

A mixture prepared in advance of 4.2 g of formic acid 7,511 water and 90% hydrogen peroxide 1.7 M, V 13.42 I
I was added dropwise from the dropping funnel while stirring over a period of about 55 minutes (formic acid concentration 77°4 wt%).

Although heat generation is observed as the mixture is dropped, the liquid temperature is maintained at 29 to 50°C by cooling with water if necessary.

65 minutes after the completion of dropping, the temperature was maintained at 29°C, and then the liquid temperature was increased to 35°C.
The solution temperature was raised to 40°C and reacted for 1 hour, then the solution temperature was raised to 45°C and reacted for 30 minutes, and finally the solution temperature was raised to 50°C and reacted for 30 minutes.

After the completion of the reaction, the target product was separated from the reaction mixture, and the product was analyzed by gas chromatography. As a result, 2
-Reaction rate of methyl-6-acetylnaphthalene 79.1
%, the selectivity of 2-methyl-6-acetyloxynaphthalene was 96.6%.

Example 12 In Example 1, 2-methyl-6-acetylnaphthalene was replaced with 2-methyl-6-inbutylnaphthalene 12
．． The reaction was carried out in the same manner as in Example 1 except that 1.9 was used.

Reaction rate of 2-methyl-6-inbutylnaphthalene 97
%, a selectivity of 75% for 2-methyl-6-butyryloxina 7-talene was obtained.

Example 13 2-ethyl-6-acetylnaphthalene in place of 2-methyl-6-acetylnaphthalene in Example 1 10.
The reaction was carried out in the same manner as in Example 1 except that 6.9 was used.

Reaction rate of 2-ethyl-6-acetylnaphthalene: 94%
A selectivity of 90% for -2-ethyl-6-acetyloxynaphthalene was obtained.

Example 14 In Example IKn, 2-methyl-6'-acetylnaphthalene was replaced with 2-methyl-6-neopentylnaphthalene.
The reaction was carried out in the same manner as in Example 1 except that 12.8p was used.

Reaction rate of 2-methyl-6-neopentylnaphthalene 9
5%, a selectivity of 75% for 2-methyl-6-neopentylyloxynaphthalene was obtained.

Comparative Example 1 Formic acid 5.26. Add S+ and 2-methyl-6-acetylnaphthalene and keep at 50°C on a water bath with stirring.

In advance, formic acid 4.85g, water 0.14,! / and 90
% hydrogen peroxide (2.19.V) was added dropwise from the dropping funnel while stirring over a period of 46 minutes (formic acid concentration: 96.6%, water concentration: 3.43%). Heat generation is observed as the dripping occurs, but if necessary, cool with water to lower the liquid temperature to 50~50℃.
Hold at 55°C.

After reaction at 50-55°C for 6 hours after completion of dropping.

As a result of analyzing the target product by gas chromatography,
Reaction rate of 2-methyl-6-acetylnaphthalene 70.
The selectivity for 2-methyl-6-acetyloxynaphthalene was 66.4%.

Comparative Example 2 In a reactor equipped with a stirrer, a reflux condenser, and a dropping funnel, 2.59. Ethyl acetate 5.02J/and 2
-Methyl-6-acetylnaphthalene 7.51 J/ is added and kept at 50°C on a water bath while stirring.

A mixture of 2.5 I of formic acid, 1.5 Y of water, and 2.21 g of 90% hydrogen peroxide was added dropwise from the dropping funnel with stirring over 28 minutes (formic acid concentration: 42.6
%). Heat generation is observed as the solution is dropped, but the temperature of the solution is maintained at 55°C by cooling with water as required.

After the reaction at 55"C for 6 hours after the completion of the dropwise addition, the desired product was analyzed by gas chromatography.

Reaction rate of 2-methyl-6-acetylnaphthalene 64%,
Selectivity of 2-methyl-6-acetyloxynaphthalene
It was 84.6%.

Comparative Example 6 2.5 g of formic acid, 5.0 g of ethyl acetate, and 7.56 y of 2-methyl-6-acetylnaphthalene were added to a reactor equipped with a stirrer, a reflux condenser, and a dropping funnel, and the mixture was heated on a water bath while stirring. Hold at 58°C.

2.5 I of formic acid in advance! , water o, 1sy and 90% hydrogen peroxide 2.24.9 was added dropwise from the dropping funnel with stirring over a period of 48 minutes (formic acid concentration 4
8.2%, water concentration 3°61%). Heat generation is observed as the solution is dropped, but the temperature of the solution is maintained at 55° C. by cooling with water if necessary.

After the reaction at 55°C for 3 hours and 10 minutes after the completion of the dropwise addition, the target product was analyzed by gas chromatography, and the reaction rate of 2-methyl-6-acetylnaphthalene was 67.8%, 2-
Selectivity of methyl-6-acetyloxynaphthalene 74
．． It was 5%.

Claims (1)

[Claims] The following general formula (I) ▲ Numerical formulas, chemical formulas, tables, etc. are included ▼ (I) [In the formula, R_1 is an alkyl group having 1 to 4 carbon atoms, and R_2 is an alkyl group having 1 to 10 carbon atoms. Alternatively, it represents an alkoxy group, and n=1 to 4. ] with 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. A method for producing acyloxynaphthalene and its derivatives characterized by