JPS6140242A - Production of acyloxynaphthoic acid - Google Patents

Abstract

PURPOSE:To obtain the titled compound in high selectivity, by reacting an acylalkylphthalene compound with a peroxide to give an acyloxyalkylnaphthalene compound, and oxidizing the resultant acyloxyalkylnaphthalene compound with molecular oxygen in the presence of a specific catalyst. CONSTITUTION:An acylalkylnaphthalene compound expressed by formula I (R1 is 1-3C alkyl; R2 is H or 1-3C alkyl) is reacted with a peroxide to give a compound expressed by formula II, which is then oxidized with molecular oxygen in the presence of a bromine compound-cobalt compound or bromine compound- cobalt compound-manganese compound catalyst in an organic solvent, e.g. formic aicd to give the aimed acyloxynaphthoic acid. Before oxidizing the compound expressed by formula II, recrystallization from acetic anhydride can be carried out under heating to improve the reaction conversion to 100mol%. Thus, the aimed compound can be obtained in high selectivity without forming isomers as a by-product.

Description

Detailed Description of the Invention [Industrial Application Field] The present invention uses an acylalkylnaphthalene compound as a starting material, reacts the compound with a peroxide such as hydrogen peroxide to obtain an acyloxyalkylnaphthalene compound, and then The present invention relates to a method for producing the corresponding acyloxy naphthoic acid by oxidizing the compound with molecular oxygen.

The acyloxy-naphthoic acid compound obtained by the method of the present invention can be used as it is or in the form of a hydroxyl group by hydrolyzing the acyloxy group, and is a compound useful as a raw material for synthetic resins or as a raw material for synthetic fibers.

[Conventional technology]

Conventionally, a, 7. Oki 2. An example of a method for producing toic acid is the so-called Kolbeschmint method, which uses β-naphthol as a raw material. (Japanese Patent Publication No. 5123494) In this method, even if the raw material β-naphthol is highly purified, a non-negligible amount of isomers are produced during the reaction.
It is not possible to selectively obtain only a specific one such as -16 integral or 2-17 integral. Further, since β-naphthol is reacted as an alkali metal salt, it is necessary to perform a neutralization treatment after the reaction, and furthermore, waste treatment is required, which is complicated. In addition, methods for oxidizing alkylbenzenes having an acyloxy group in the presence of a fermentation catalyst include, for example, Japanese Patent Publication No. 42-849, Japanese Patent Publication No. 50
-35066, etc. The former is a method in which p-cresyl acetate is oxidized at 100 to 140°C in the presence of a cobalt catalyst to obtain p-acetoxybenzoic acid. In this method, the conversion rate of p-cresyl acetate is only 12 mo1%.

The latter invention is an improvement on the former, and is a method in which an organic carboxylic acid or its anhydride is used as a solvent and a three-component system of a bromine compound, a cobalt compound and a manganese compound is used as a catalyst.

It is also known to oxidize alkylnaphthalene compounds such as methylnaphthalene and dimethylnaphthalene with molecular oxygen in the presence of a heavy metal catalyst to obtain naphthoic acid or naphthalene dicarboxylic acid.

However, there are no examples of air oxidation of alkylnaphthalene compounds having an acyloxy group, and in order to prevent the oxidative decomposition of the naphthalene nucleus, which is much more susceptible to oxidative decomposition than alkylbenzenes, and efficiently oxidize only the side chain alkyl group,
(11) It is necessary to set mild conditions to prevent oxidative decomposition of the naphthalene nucleus; (2) On the other hand, since it has an acyloxy group, there are constraints such as the need for correspondingly modified reaction conditions. It was predicted that it would not be easy to selectively and efficiently oxidize only the side chain alkyl group simply by applying the conventional technology for acyloxyalkylbenzene, and in fact, the acyloxyalkylnaphthalene compound as in the present invention was directly oxidized with air. Up to now, it has not been known to oxidize to obtain acyloxy naphthoic acids.

[Problem that the invention seeks to solve]

The object of the present invention is to directly air oxidize an acyloxyalkylnaphthalene compound, which has not been done conventionally, to obtain the corresponding acyloxynaphthoic acid compound with good selectivity without producing isomer by-products.

[Means for solving problems]

The present invention has been developed as a result of studies on a method for efficiently obtaining acyloxy naphthoic acids without isomers, for example, only 2-16 monomers and only 2-17 monomers, using an acylalkyl-phthalene compound as a starting material, The acylalkylnaphthalene compound is reacted with hydrogen peroxide, an organic peracid, or a mixture thereof to obtain an acyloxyalkylnaphthalene compound, and then the compound is oxidized with molecular oxygen, thereby producing isomers as by-products. The present invention was accomplished by discovering that only naphthoic acid, which is the target product, can be obtained without the use of naphthoic acid.

That is, the present invention provides: (1) General formula (I) (wherein, R1 is an alkyl group having 1 to 3 carbon atoms, and R2 is a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.) An acylalkylnaphthalene compound is reacted with a peroxide to obtain an acyloxyalkylnaphthalene compound represented by the following general formula (II), and the compound is mixed into a bromine compound-cobalt compound, or a bromine compound-cobalt compound- A method for producing acyloxy naphthoic acid, characterized by oxidation with molecular oxygen in the presence of a manganese compound catalyst.

(Hereinafter referred to as general formula (II)) (In the formula, R, and R2 are the same as above.) Further, the present inventors conducted extensive studies on the oxidation of the acyloxyalkylnaphthalene compound, and found that the oxidation reaction by molecular oxygen The reaction raw material conversion rate was approximately 60 mo1%.
A phenomenon that remained in the following was observed.

In such cases, measures such as raising the reaction temperature or increasing the catalyst concentration are usually taken to increase the reaction conversion rate. However, in the case of acyloxyalkylnaphthalene compounds, which are the target substances of the present invention, it is necessary to prevent the oxidation of the naphthalene nucleus and efficiently oxidize the side chain alkyl group, and simply raising the reaction temperature causes decomposition of the naphthalene nucleus. Desirable.

Therefore, various studies were conducted in order to increase the reaction conversion rate of the acyloxyalkylnaphthalene compound, and it was found that long before the oxidation reaction, the acyloxyalkylnaphthalene compound was recrystallized with acetic anhydride under heating and subjected to a post-oxidation reaction. It was found that the reaction conversion rate could be increased to 100 mo1%.

The method of the present invention will be explained in detail below.

First, the reaction between the acylalkylnaphthalene compound and the peroxide in the present invention is carried out in an organic solvent.

As the organic solvent in this case, a mixed solvent of a lower fatty acid having 1 to 4 carbon atoms, an ester of a lower fatty acid having 1 to 4 carbon atoms, and at least one type of aromatic hydrocarbon is used. Examples of these organic solvents include formic acid, acetic acid, propionic acid, ethyl acetate, benzene, toluene, xylene,
Examples include.

Further, the amount of water in the reaction solvent should be as small as possible, preferably <20 wt% or less, preferably 15 wt% or less.

The amount of solvent is 2 to 1 of the raw material acylalkylnaphthalene compound.
0x amount is used.

As the peroxide, hydrogen peroxide, an organic peracid, or a mixture thereof is used, and industrially hydrogen peroxide is preferable, and the concentration of hydrogen peroxide is preferably 60 to 90%. The amount used is 1 to 10 times the mole of the raw material acylalkylnaphthalene compound.

In this reaction, the reaction temperature is usually 30 to 150°C, and the reaction time is about 30 minutes to 3 hours.
By appropriately selecting reaction conditions, the reaction can be completed within 30 minutes. After the reaction is completed, the reaction product is cooled to precipitate crystals to obtain crystals of acyloxyalkylnaphthalene. Further, if necessary, the crystals are rinsed with the same solvent used in the reaction. Next, the acyloxyalkylnaphthalene compound thus obtained is subjected to an oxidation reaction with molecular oxygen.

In this reaction, a mixed solvent of a lower organic fatty acid having 2 to 4 carbon atoms and acetic anhydride is used as a reaction solvent. The concentration of acetic anhydride in the reaction solvent may vary depending on the weight ratio of solvent/acyloxyalkylnaphthalene compound, but is preferably at least 2 wt% or more. It is desirable that the amount of water in lower organic fatty acids having 2 to 4 carbon atoms is small;
Any commercially available material may be used, and in general, 1% by weight or less is used. The amount of this solvent to be used is at least twice, preferably 3 to 20 times, the amount of the acyloxyalkylnaphthalene compound used as the raw material.

Next, the catalyst used in the oxidation reaction of the present invention is a two-component system consisting of a bromine compound and a cobalt compound, or a three-component system in which a manganese compound is further added. As the bromine compound, cobalt bromide, hydrobromic acid, manganese bromide, ammonium bromide, etc. are used, and the amount used is 500 wtppz or more as Br, preferably 1000 to 1000010000, based on the solvent. Examples of cobalt compounds include cobalt bromide and cobalt acetate, and the amount used is 300 i as Co relative to the solvent.
vt ppm or more, preferably 500 to 5000 wt
ppm. Further, examples of manganese compounds include manganese bromide and manganese acetate, which are 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 will decompose, which is undesirable, and if the temperature is lower than 100°C, the reaction will not proceed sufficiently, which is undesirable. In addition, the reaction pressure is normal pressure to 200
kg/cIIVG, oxygen partial pressure 401g/antG, J,
Although an oxygen partial pressure of zero is not preferable, the reaction proceeds satisfactorily even if the oxygen partial pressure is 2 kg/crA G or less. The molecular oxygen of the present invention is an oxygen gas or an oxygen-containing gas diluted with an inert gas, such as air,
Either can be used.

Further, in the present invention, a heating recrystallization treatment of an acyloxyalkylnaphthalene compound with acetic anhydride performed prior to the oxidation reaction to improve the conversion rate in the oxidation reaction of the acyloxyalkylnaphthalene compound will be described.

The amount of acetic anhydride used in the above heating recrystallization treatment is 3 times or more, preferably 5 to 10 times the weight of the acyloxyalkylnaphthalene compound crystal. If it is less than 3 times by weight, the effect of the recrystallization treatment will not be apparent, and if it is more than 10 times by weight, the yield of crystals obtained after the treatment will be low, which is not preferable.

Further, the heating temperature may be any temperature that melts the crystals, and is usually 35 to 140°C. Heating may also be performed under pressure, but industrially it is usually treated under normal pressure.

The heating time may be a time sufficient to uniformly dissolve the crystals of the acyloxyalkylnaphthalene compound in acetic anhydride. The post-heating treatment liquid is cooled, and this cooling may be done by either water cooling or water cooling, but water cooling is preferred in order to increase the yield of crystals.

The crystals thus obtained are rinsed with acetic anhydride, and the amount of acetic anhydride used for this rinsing may be sufficient to remove the mother liquor adhering to the crystals.

Specifically, the acylalkyl phthalene compound represented by the general formula (I) used in the present invention is, for example, 2-
Methyl-6-acetylnaphthalene, 2-methyl-6-propionylnaphthalene, 2-methyl-6-isobutyrylnaphthalene, 2-methyl-7-acetylnaphthalene, 2
-Methyl-7-propionylnaphthalene, 2-methyl-
7-isobutyrylnaphthalene, 2-ethyl-6-acetylnaphthalene, 2-ethyl-6-propionylnaphthalene, 2-ethyl-6-isobutyrylnaphthalene, 2-
Ethyl-7-acetylnaphthalene, 2-ethyl-7-propionylnaphthalene, 2-ethyl-7-isobutyrylnaphthalene, 2-isopropyl-6-acetylnaphthalene, 2-isopropyl-6-propionylnaphthalene,
2-isopropyl-6-isobutyrylnaphthalene, 2-
Isopropyl-7-acetylnaphthalene, 2-isopropyl-7-propionylnaphthalene, 2-isobutyrylnaphthalene, 1-methyl-6-acetylnaphthalene, 1-methyl-6-propionylnaphthalene, 1-methyl- 6-isobutyrylnaphthalene, l
-Methyl-7-acetylnaphthalene, 1-methyl-7-
Examples include propionylnaphthalene and -methyl-7-butyridyl phthalene.

Further, the acyloxyalkylnaphthalene compound represented by the general formula (II) is specifically, for example, 2-methyl-6-acetyloxynaphthalene, 2-methyl-6-acetyloxynaphthalene,
-propyloxynaphthalene, 2-methyl-6-isobutyryloxynaphthalene, 2-methyl-7-acetyloxynaphthalene, 2-methyl-7-propyloxynaphthalene, 2-methyl-1-isobutyryloxynaphthalene, 2-ethyl-6-acetyloxynaphthalene, 2
-ethyl-6-propyloxynaphthalene, 2-ethyl-6-isobutyryloxynaphthalene, 2-ethyl-7
-Acetyloxynaphthalene, 2-ethyl-7-propyloxynaphthalene, 2-ethyl-7-isobutyryloxynaphthalene, 2-isopropyl-6-acetyloxynaphthalene, 2-isopropyl-6-propyloxynaphthalene, 2-isopropyl -6-isobutyryloxynaphthalene, 2-isopropyl-7-acetyloxynaphthalene, 2-isopropyl-7-propyloxynaphthalene, 2-isopropyl-7-isobutyryloxynaphthalene, 1-methyl-6-acetyloxynaphthalene , 1-methyl-6-propyloxynaphthalene, ■-
Methyl-6-butyridylxinaphthalene, 1-methyl-7-acetyloxynaphthalene, 1-methyl-7-
Examples include propyloxynaphthalene, 1-methyl-7-isobutyryloxynaphthalene, and the like.

〔Effect of the invention〕

According to the present invention, the desired acyloxy-naphthoic acid can be produced with good selectivity without isomer by-products, and the acyloxyalkylnaphthalene compound can be
Oxidation can be carried out at a high reaction conversion rate of 0 mo1%, and a naphthoic acid compound having an acyloxy group can be obtained at a high rate. The naphthoic acid compound remains as it is,
Alternatively, the acyloxy group is hydrolyzed to form a hydroxyl group, which is used as a raw material compound for synthetic resins or synthetic fibers.

Naphthoic acid compounds obtained by the method of the present invention, e.g.
-Acetoxy-6-naphthoic acid has recently attracted attention as a raw material for high-strength polyester fibers, and the present invention is extremely significant because it can supply such naphthoic acid industrially.

〔Example〕

Next, examples of the present invention will be described.

Example 1 Reverse vessel with stirrer, reflux condenser and dropping funnel
60 parts of ethyl acetate, 2-methyl-6-
1729.2 parts of acetyl naphtha was added and heated to 50° C. with stirring. A mixture of 40 parts of acid and 66.0 parts of 90% hydrogen peroxide was then added dropwise from the dropping funnel. Since heat generation was observed during the dropping, the dropping rate was adjusted and the internal temperature was maintained at 50°C by cooling as necessary.

After the dropwise addition was completed, the same temperature was maintained for 2 hours to complete the reaction.

After the reaction was completed, the contents were cooled to obtain crystals of 2-methyl-6-acetyloxyalkylnaphthalene. The crystals were rinsed with ethyl acetate and then dried under reduced pressure at 60°C.

Next, 30 parts of the 2-methyl-6-acetyloxyalkylnaphthalene crystals were mixed with 240 parts of acetic anhydride prior to oxidation, heated at 95°C, cooled, and the crystals were filtered off.

This was used as a raw material for an oxidation reaction.

2 in a titanium pressure-resistant container with an internal volume of 200 cc and a stirrer.
-Methyl-6-acetyloxinac 1 fluoride 10 parts, acetic acid 80 parts, acetic anhydride 20 parts, cobalt acetate tetrahydrate 0. 2
49 (Co=59'Owt ppm), 0.245 parts of manganese acetate tetrahydrate (Mn=550Wt ppm)
), ammonium bromide 0. 250 (Br, =
2040. wt ppm), 25kg/c
After pressurizing nTG, it was heated to 120℃, and the air was turned into ION.
Aeration was performed at a rate of β/hr. The reaction was terminated when no oxygen was absorbed.

Reaction time was 2.5 hours. After cooling, the contents were taken out and analyzed. As a result, the conversion rate of 2-methyl-6-acetyloxynaphthalene was 100 mo1%, and the yield of 2-acetyloxy-6-naphthoic acid was 68.5 mo1.
% (selectivity 68.5 mo1%).

In addition, 2-acetoxy-6-nafdaldehyde is 23.
5 mo1% was produced.

Example 2 - 2-Methyl-6-acetyloxynaphthalene obtained in the first step of Example 1 was used in the same reactor as in Example 1 without recrystallizing it with acetic anhydride prior to oxidation. An oxidation reaction using molecular oxygen was carried out in the same manner as in Example 1 using the same catalyst.

The reaction time was 2.4 hours. As a result of analyzing the product after the reaction, the conversion rate of 2-methyl-6-acetyloxynaphthalene was 55.5 mo1%, and the yield of 2-acetoxy-6-naphthoic acid was 40.0 mo1% (selectivity 72 mo1%). In addition, 8.88 mo1% of 2-acetoxy-6-nafdaldehyde was produced.

Example 3 Using the same reactor as in Example 1, 40 parts of formic acid and 27.2 parts of 2-methyl-6-isobutyrylnaphthalene were added and heated to 50°C with stirring. A mixture of 32.2 parts of phosphoric acid and 5.36 parts of 90% hydrogen peroxide was then added dropwise. Since heat generation was observed during the dropwise addition, the reaction was terminated in the same manner as in Example 1.

The reaction product was treated as in Example 1 to give 2-methyl-6
-isobutyryloxynaphthalene was obtained.

Next, 30 parts of the 2-methyl-6-butyryloxyalkylnaphthalene crystals were mixed with 180 parts of acetic anhydride prior to oxidation.
After heating to 140° C., the crystals were filtered out and used as a raw material for the oxidation reaction.

30 parts of the above 2-methyl-6-isobutyryloxynaphthalef, 80 parts of acetic acid, 20 parts of acetic anhydride, 4 parts of cobalt acetate
1.87 parts of aqueous salt (Go=4425iyt ppm),
Ammonium bromide 1.08 parts (Br=8813ut
29m) and pressurized to 10kg/c+JG, then 1
Heat to 50℃ and add 10NI of air! Aeration was carried out at a rate of /hr, and the reaction was terminated when no oxygen was absorbed.

The reaction time was 2.4 hours. After cooling, the contents were taken out and analyzed. As a result, the conversion rate of 2-methyl-6-isobutyryloxynaphthalene was 100m.

1%, 2-isobutyryloxy-6-naphthoic acid yield is 65', Omo1% (selectivity 65.0mo1%)
Met. Note that 21.0 mo1% of 2-isobutyryloxy-6-nataldehyde was produced.

Example) In a container similar to that used in Example 1, 2-methyl-7-
Prior to oxidation, 34.2 parts of propyloxynaphthalene crystals were mixed with 273.6 parts of acetic anhydride, heated to 95°C, cooled, and filtered to separate the crystals, which were used as a raw material for the oxidation reaction.

2-Methyl-7-propyloxynaphthalene 11 above
゜4 parts, acetic acid 90 parts, acetic anhydride 10 parts, acetic acid per liter/L/
0.249 parts of tetrahydrate (Go = 590 wtppm
), 0.245 parts of manganese acetate tetrahydrate (Mn=550
wtppm), ammonium bromide A0.250 part (
Prepare Br=2040wtppm>, 8k+r
/ciG and heated to 5180°C, and air was passed through at a rate of 10NN/hr. The reaction was terminated when no oxygen was absorbed. The reaction time was 2 hours. After cooling, the contents were taken out and analyzed. As a result, the conversion rate of 2-methyl-7-propyloxynaphthalene was 100IIlo1%, and the yield of 2-propyloxy-7-naphthoic acid was 51.0mol1% (selectivity 51 mo1).
%)Met.

In addition, 2-propyloxy-7-nathaldehyde is 1
9+no1% was produced.

Patent applicant: Mitsubishi Gas Chemical Co., Ltd. Agent, Patent attorney: Sadami Kobori Procedural amendment (spontaneous) Date: April 12, 1985 Patent Application No. 163402, filed in 1985 2, Title of invention: Process for producing acyloxy naphthoic acid 3 , Relationship with the case of the person making the amendment Patent applicant address (◎100) 2-5-2 Marunouchi, F Daita-ku, Tokyo Name (44G) Mitsubishi Gas Chemical Co., Ltd. Representative Nagano Washo 4, Agent address (◎100) ) Mitsubishi Gas Chemical Co., Ltd., 2-5-2 Marunouchi, Chiyoda-ku, Tokyo (283-5125) Column 6 of "Detailed Description of the Invention", Contents of Amendments (11, page 10, 3- In the fourth line, "bromine metal objects" is corrected to "bromine compounds."

(2) page 13, lines 16-17, and page 14,
In the 2nd and 3rd lines, "2-methyl-6-propyloxynaphthalene" is corrected to "2-methyl-6-propionyloxynaphthalene".

(3) Same, lines 19-20, page 14, lines 5-6, page 19, lines 11-12, line 16, and page 20, lines 5-6. "2-Methyl-7-propyloxynaphthalene" is corrected to "2-methyl-7-propionyloxynaphthalene".

(4) Page 14, lines 8-9 “2-isopropyl-6-propyloxynaphthalene J
t-r2-isopropyl-6-propionyloxynaphthalene".

(5) Same, lines 11-12 [2-isopropyl-7-propyloxynaphthalene]
is corrected to "2-isopropyl-7-propionyloxynaphthalene".

(6) Same, lines 17-18, “1-methyl-7-propyloxynaphthalene” is changed to “1-methyl-7-propyloxynaphthalene”.
-Methyl-7-propionyloxynaphthalene".

(7) Same, lines 14-15, “1-methyl-6-propyloxynaphthalene” is changed to “1-methyl-6-propyloxynaphthalene”
-Methyl-6-propionyloxynaphthalene".

(8) Page 16, line 3 Correct r66, OJ to r6.60J.

(9) On page 20, line 7, [2-propyloxy-7-naphthoic acid] is corrected to "2-propionyloxy-7-naphthoic acid."

00) Same, line 9, [2-propyloxy-7-naphthaldehyde] is changed to “2
-propionyloxy~7-nafdaldehyde”.

Claims (2)

[Claims] (1) General formula (I) ▲Mathematical formulas, chemical formulas, tables, etc.▼(I) (In the formula, R_1 is an alkyl group with 1 to 3 carbon atoms, and R_2 is a hydrogen atom or an alkyl group with 1 to 3 carbon atoms. ) is reacted with a peroxide to obtain an acyloxyalkylnaphthalene compound represented by the following general formula (II), and the compound is mixed with a bromine compound-cobalt compound, Alternatively, acyloxy-
Method for producing naphthoic acid. General formula (II) ▲There are mathematical formulas, chemical formulas, tables, etc.▼(II) (In the formula, R_1 and R_2 are the same as above) (2) the acyloxyalkylnaphthalene compound,
The method according to claim 1, characterized in that prior to oxidation with molecular oxygen, a heating recrystallization treatment is performed with acetic anhydride.