JP2912177B2 - Method for producing acyloxybenzoic acid or a salt thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a process for producing acyloxybenzoic acid or a salt thereof useful as a bleach activator in an oxygen-based bleach. More specifically, an acylating agent is allowed to act on hydroxybenzoic acid or a salt thereof to produce an acyloxybenzoic acid or a salt thereof. The present invention relates to a method for producing a salt.

[0002]

2. Description of the Related Art Acyloxybenzoate, like acyloxybenzenesulfonate, is combined with hydrogen peroxide-generating substrates and hydrogen peroxide represented by PC (sodium percarbonate), PB (sodium perborate) and the like in water. Organic peracid is easily generated even at low temperatures by contact, and stains on clothing, etc.
It is a compound that is particularly useful as a bleach activator because it effectively exhibits bleaching performance against stain stains (JP-A-6-21).
No. 1746, JP-A-6-145697). In this method for producing an acyloxybenzoate, any of the methods described in the above publications cannot provide a high-purity product, requires a purification operation using a solvent, and is not suitable for a commercial production process.

[0003] Therefore, there has been a demand for the development of a method for industrially producing acyloxybenzoic acid and its salt with high selectivity and high yield. An object of the present invention is to provide an industrial production method capable of producing an acyloxybenzoic acid or a salt thereof at a high selectivity, in a high yield, and at a low cost in producing a high-purity acyloxybenzoic acid or a salt thereof. It is in.

[0004]

The present inventors have conducted intensive studies on the reaction between hydroxybenzoic acid or a salt thereof and an acylating agent in order to solve the above-mentioned problems. Surprisingly, the present inventors have found that a higher conversion and selectivity than ever before can be obtained, and high-purity acyloxybenzoic acid or a salt thereof can be produced, and the present invention has been completed. That is, the present invention
General formula (1)

[0005]

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[Wherein, M ¹ and M ^{2 represent a} hydrogen atom, or an alkali metal, alkaline earth metal, ammonium, substituted ammonium or quaternary ammonium, and M ¹ and M ² may be the same or different. Is also good. m: represents the number of 1 to 3. With hydroxybenzoic acid or a salt thereof or a mixture thereof represented by the formula (2)

[0007]

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Wherein M ¹ and M ² have the same meanings as described above. R ¹ : a linear or branched alkyl or alkenyl group having ^{1 to} 21 carbon atoms, which may be substituted with a halogen and may have an ester group, an amide group, an ether group or a phenylene group inserted, or A straight-chain or branched-chain alkyl group or alkenyl group which may be unsubstituted or substituted with a halogen having 1 to 22 carbon atoms and which may have an ester group, an amide group, an ether group or a phenylene group inserted therein, or a halogen. Represents a phenyl group which may be substituted. h: Indicates the number of 1 to 3. i: Indicates the number obtained by subtracting h from m. Here, m has the same meaning as described above. When producing the acyloxybenzoic acid or a salt thereof or a mixture thereof represented by the general formula (3):

[0009]

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[Wherein R ² is a straight-chain or branched-chain having 1 to 21 carbon atoms, which may be substituted with halogen and may have an ester group, an amide group, an ether group or a phenylene group inserted therein. An alkyl group or an alkenyl group, or a straight-chain or branched-chain which may be unsubstituted or substituted with 1 to 22 carbon atoms, may be substituted with halogen, and may have an ester group, an amide group, an ether group or a phenylene group inserted therein. It represents an alkyl group, an alkenyl group, or a phenyl group optionally substituted with halogen. ] The reaction is carried out in the presence of a carboxylic acid represented by the following formula:

Hereinafter, the present invention will be described in detail. The hydroxybenzoic acid or a salt thereof as a raw material of the present invention is represented by the above general formula (1), wherein M ¹ and M ² represent a hydrogen atom, an alkali metal, an alkaline earth metal, ammonium, substituted ammonium Or quaternary ammonium, but M ¹ , M ²
May be the same or different. Li, Na, K, etc. as alkali metals, M as alkaline earth metals
g, Ca and the like. Specific examples of the substituted ammonium include monomethylammonium, dimethylamine, trimethylamine, monoalkylamine having 2 to 14 carbon atoms or monoalkyldimethylamine, triethanolamine, monoethanolamine, methylmonoethanolamine, and dimethylmonoethanol. Amine, diethanolamine, methyldiethanolamine, 2-C
And monoalkyldiethanolamine, pyridine, piperidine, ethylenediamine, diethylenetriamine, N, N-dimethylaminopropylamine, and ammonium such as aminoethylethanolamine. However, ethanolamines which can easily react with the acylating agent even under acidic conditions during the esterification reaction may complicate the reaction and give undesirable results depending on the purpose. Specific examples of the quaternary ammonium include monoalkyltrimethylammonium having 1 to 24 carbon atoms which may be single or mixed or unsaturated, and single or mixed having 1 to 20 carbon atoms. And dialkyldimethylammonium, which may be unsaturated or unsaturated, and tetraalkylammonium having 1 to 4 carbon atoms. Among these, from the viewpoint of water solubility and performance of acyloxy benzoic acid or a salt of the desired product, in particular Li, K, Na, Mg, ammonium (NH ₄ ⁺⁾
Is preferable, and Li, K and Na are particularly preferable. Further, the number of substituents m of the active site capable of reacting with the acylating agent shows 1 to 3, and can be selected according to the water solubility of the target product.
Preferably it is 1.

Specific examples of the hydroxybenzoic acid represented by the general formula (1) or a salt thereof include salicylic acid, p-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid, and 2,5-
Examples thereof include dihydroxybenzoic acid, 3,4,5-trihydroxybenzoic acid, or a Na salt, a K salt, a Li salt, a Mg salt thereof.
Among them, salicylic acid, p-hydroxybenzoic acid, 2,4-dihydroxybenzoic acid or Na
The use of salts, K salts or Mg salts is preferred and practical.
Further, salicylic acid, p-hydroxybenzoic acid or its Na salt, K salt or Mg salt is particularly preferred from the viewpoint of raw material cost.

The hydroxybenzoic acid represented by the general formula (1) or a salt thereof is commercially available as a corresponding acid or salt, and any of them can be used. The dehydration of hydroxybenzoic acid or a salt thereof generally requires conditions such as high temperature or azeotropic dehydration under an inert gas stream, and its improvement is desired. However, it is used in the reaction of the present invention as described later. By adding the carboxylic acid represented by the general formula (3) before or after neutralization, the drying of hydroxybenzoic acid or a salt thereof can be performed extremely well in terms of physical properties and equipment, and thus it is preferable.

The hydroxybenzoic acid represented by the general formula (1) or a salt thereof used in the present invention is preferably used in a substantially anhydrous form. Here, the term "substantially anhydrous" does not refer to a completely anhydrous state, but refers to a substantially anhydrous state if a small amount of water contained in the raw material itself, for example, 0.5% by weight or less. When a substantial amount of water is present, hydrolysis of the acylating agent occurs, and the reaction yield decreases. Dehydration is carried out if necessary. Specifically, for example, 0.05 to 1 part by weight of hydroxybenzoic acid or a salt thereof represented by the general formula (1) before or after neutralization is used.
20 parts by weight of a carboxylic acid represented by the general formula (3) is added, mixed by stirring or kneading, and dispersed well.
The treatment may be carried out at a temperature of 10 to 200 ° C. under a reduced pressure of 5 to 500 Torr for 1 to 10 hours.

Specific examples of the carboxylic acid represented by the general formula (3) used in the present invention include acetic acid, n-propionic acid, n-butyric acid, n-hexanoic acid, n-heptanoic acid and i-
Heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid,
n-nonanoic acid, i-nonanoic acid, 3,5,5-trimethylhexanoic acid, n-decanoic acid, i-decanoic acid, n-undecanoic acid, i-undecanoic acid, lauric acid, myristic acid, palmitic acid, stearin Acid, isostearic acid,
Fatty acids represented by behenic acid, etc., aromatic carboxylic acids represented by benzoic acid, methylbenzoic acid, octylbenzoic acid, etc., chloroacetic acid, chlorobutyric acid, bromobutyric acid, chlorocaproic acid, bromocaproic acid, chloroundecanoic acid And phenylacetic acid, phenylpropionic acid and the like, and arylalkylcarboxylic acids and the like. Among these carboxylic acids, acetic acid, n-propionic acid, n-butyric acid, and n-hexanoic acid are preferred in that the function of the bleach activator of the product is not impaired by a transesterification reaction that may occur during the esterification reaction. , N-heptanoic acid, i-heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid, n-nonanoic acid, i-nonanoic acid, n-decanoic acid, i-decanoic acid, n-undecanoic acid,
i-undecanoic acid, lauric acid, myristic acid, and linear or branched fatty acids having 2 to 16 carbon atoms, such as palmitic acid, are good. In order to obtain, a linear or branched fatty acid having 2 to 14 carbon atoms is preferable. Further, in the sense that the same composition can be obtained by the esterification reaction, the carboxylic acid represented by the general formula (3) and the carboxylic acid residue of the acylating agent are the same, for example, particularly, hydrophilic stains, In order to obtain lauroyloxybenzoic acid or a salt thereof having a well-balanced effect on hydrophobic soil, lauric acid is particularly preferred.

The acylating agent used in the esterification of the present invention is represented by the general formula (4)

[0017]

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Wherein R ¹ has the same meaning as described above. X: represents a halogen atom. A carboxylic acid halide represented by the general formula (5):

[0019]

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Wherein R ¹ has the same meaning as described above. R ^3: 1 to 21 carbon atoms, may be substituted by halogen, an ester group, an amide group, a linear optionally an ether group or a phenylene group is inserted or branched chain alkyl or alkenyl group or, A straight-chain or branched-chain alkyl group or alkenyl group which may be unsubstituted or substituted with a halogen having 1 to 22 carbon atoms and which may have an ester group, an amide group, an ether group or a phenylene group inserted therein, or a halogen. Represents a phenyl group which may be substituted, and may be the same as or different from R ¹ . A carboxylic acid anhydride represented by the formula:

Specific examples of the carboxylic acid halide represented by the general formula (4) used in the present invention include the following acid chlorides, acid bromides, acid fluorides and acid iodides of carboxylic acids. That is, acetic acid, n-propionic acid, n-butyric acid, n-hexanoic acid, n-heptanoic acid, i-
Heptanoic acid, n-octanoic acid, 2-ethylhexanoic acid,
n-nonanoic acid, i-nonanoic acid, 3,5,5-trimethylhexanoic acid, n-decanoic acid, i-decanoic acid, n-undecanoic acid, i-undecanoic acid, lauric acid, myristic acid, palmitic acid, stearin Acid, isostearic acid,
Fatty acids represented by behenic acid, etc., aromatic carboxylic acids represented by benzoic acid, methylbenzoic acid, octylbenzoic acid, etc., chloroacetic acid, chlorobutyric acid, bromobutyric acid, chlorocaproic acid, bromocaproic acid, chloroundecanoic acid Halogenated alkyl carboxylic acids represented by phenylacetic acid, carboxylic acid halides such as arylalkyl carboxylic acids represented by phenylpropionic acid can be used, among others, in terms of the function of the acyloxybenzene sulfonate bleach activator. Acetic acid, n-propionic acid, n-butyric acid, n
-Hexanoic acid, n-heptanoic acid, i-heptanoic acid, n-
Octanoic acid, 2-ethylhexanoic acid, n-nonanoic acid, i
-Carboxylic acid halides of nonanoic acid, n-decanoic acid, i-decanoic acid, n-undecanoic acid, i-undecanoic acid, lauric acid, myristic acid and palmitic acid are good, and further, hydrophilic stains and hydrophobic stains In order to obtain a good effect and water solubility, a halide of a linear or branched fatty acid having 2 to 14 carbon atoms is preferable.

The halide of the carboxylic acid halide represented by the general formula (4) may be any of F, Cl, Br, I, etc. since there is no difference in the reaction. Certain carboxylic acid chlorides are cost effective. Further, the carboxylic acid halide may be either an undistilled product or a distilled product.However, in the hue of the acyloxybenzoic acid or a salt thereof, which is a target product, it is preferable to use a distilled product, and from the viewpoint of cost. Is advantageously an undistilled product.

The general formula (5) which is another acylating agent
For the two carboxylic acid residues in the carboxylic acid anhydride represented by the following, substantially the same as the carboxylic acid residues in the carboxylic acid halide described above are selected, but the two carboxylic acid residues are It may be the same or different depending on the purpose. Any of the above acylating agents may be used alone or as a mixture, but it is preferable to use a carboxylic acid halide with little carboxylic acid by-product.

The amount of the carboxylic acid represented by the general formula (3) used in the present invention is 0.05 to 1 part by weight of the hydroxybenzoic acid represented by the general formula (1) or a salt thereof.
Good results are obtained with up to 20 parts by weight. If the amount is less than 0.05 part by weight, the reaction selectivity is inferior, so that it is not preferable. In order to obtain higher reaction selectivity, 0.2 parts by weight or more is more preferable.
Considering the productivity and the degree of freedom of blending the resulting base, the most preferable amount is 0.2 to 10 parts by weight.

The reaction of the present invention can be carried out basically without using a solvent, but if necessary, for example, toluene, xylene, ethylbenzene, cumene, 1,2-dichloroethane, trichloroethane, tetrachloroethane, trichloroethylene , Tetrachloroethylene, carbon tetrachloride, N, N-dimethylformamide, N, N-dimethylacetamide, 1,3-dimethyl-2-imidazolidinone, hexane, cyclohexane and other solvents represented by the general formula (1) For hydroxybenzoic acid or its salt
0.1 to 20 times by weight may be used.

Further, acylating agents such as carboxylic acid halides represented by the general formula (4) and carboxylic anhydrides represented by the general formula (5) include hydroxybenzoic acid represented by the general formula (1) Or, it is usually used in a molar amount of 0.5 to 2.0 times the salt thereof. Preferably, the molar ratio calculated by the following formula is 0.5 to
A good reaction yield is given at 1.2.

[0027]

(Equation 1)

Further, when the above molar ratio is 0.8 to 1.05,
A high conversion and a high selectivity of the carboxylic acid halide or carboxylic anhydride are obtained, which is particularly preferable. In addition, in monohydroxybenzoate which is one of the raw materials,
In general, salicylates that are o-forms have lower reactivity with acylating agents than p-hydroxybenzoates. Therefore, when a salicylate is used as a raw material, it is necessary to take measures such as performing a reaction for a long time.

In the present invention, the acylating agent is added dropwise to a slurry in which hydroxybenzoic acid represented by the general formula (1) or a salt thereof is well dispersed in a carboxylic acid represented by the general formula (3). The dropping of the acylating agent can be performed at a temperature equal to or higher than the melting point of the carboxylic acid used. In particular, when the carboxylic acid halide represented by the general formula (4) is used as the acylating agent, the temperature at the time of dropping is preferably 150 ° C. or lower in order to suppress a side reaction derived from the carboxylic acid halide.
Below 120 ° C. gives more favorable results. The dripping time is
Basically, it can be set within a range where the above temperature can be maintained. Further, HCl is added together with the dropwise addition of the carboxylic acid halide.
And the like, it is desirable to adjust the dropping time so that the removal can be sufficiently performed. Specifically, in the case of a batch type reaction apparatus, the time is 1 minute to 10 hours depending on the reaction scale, the reaction tank, and the type of stirring, but there is no particular limitation. A continuous reactor may be used in addition to the batch reactor. In this case, a good result is obtained in that the temperature control in the dropping zone of the acylating agent and the temperature control in the aging zone can be divided into a plurality of zones and arbitrarily controlled. Aging is above the melting point of the carboxylic acid used, 150
A temperature of not more than ℃ is good. The temperature is more preferably from 60 to 120 ° C. in that the reaction is completed in a short time and side reactions are suppressed. The aging time depends on the temperature, for example, 150
About 1 hour at 100 ° C, about 1 to 4 hours at 100 ° C, and about 1 to 6 hours at 80 ° C.

[0030]

In the present invention, a transesterification reaction involving the carboxylic acid represented by the general formula (3) occurs during the esterification reaction. This transesterification reaction may be problematic, but when the acylating agent having the desired acyl group is difficult to obtain industrially, the carboxylic acid having the desired acyl group, which is easily available, is inexpensive or available. It is also possible to prepare the target acyloxybenzoic acid or a salt thereof by a combination with an easy acylating agent. However, unless otherwise specified, it is usually preferable to select an acylating agent and a carboxylic acid having the same acyl group. The carboxylic acid used and the carboxylic acid derived from the acylating agent are contained in the reaction product. However, for example, in the case of blending in a detergent for clothing, etc., these carboxylic acids can act as one of the washing components and also effectively act on the foam removal at the time of rinsing, due to the alkali agent in the detergent. Therefore, the reaction end product in the present invention can be directly supplied as it is to the mixing of the detergent or, if necessary, to the granulation operation.

[0031]

EXAMPLES Hereinafter, the present invention will be described in more detail by way of examples, but the present invention is not limited to only these examples. The percentages in the examples are on a weight basis unless otherwise specified.

Example 1 A four-necked flask equipped with a stirrer, a thermometer, a nitrogen gas blowing tube, a Dimroth condenser equipped with a drying tube filled with granular calcium chloride, and a dropping funnel for carboxylic acid halide was prepared. 120.0 g of sodium p-hydroxybenzoate (content 99.5%, manufactured by Wako Pure Chemical Industries) and 60.0 g of lauric acid (Lunac L-98, manufactured by Kao Corporation) are weighed and placed in an oil bath capable of controlling the temperature while stirring. And heated to 60 ° C. After reaching 60 ° C., 163.2 g of lauric chloride was added dropwise over about 20 minutes. Nitrogen gas was kept flowing at a supply rate of about 500 ml / min prior to dropping. After completion of the dropwise addition, the mixture was digested at 60 ° C. for 1 hour, then further heated to 80 ° C., and aged at 80 ° C. for 4 hours.
The pressure was reduced to 200 Torr while maintaining the temperature at 80 ° C., and the hydrochloric acid was removed over 1 hour. At this time, at 80 ° C., the reaction product had a slurry-like state. As a result of quantification by liquid chromatography analysis, target substances such as sodium p-lauroyloxybenzoate were obtained in a yield of 97%. Incidentally, the yield of sodium p-lauroyloxybenzoate was 95.5%. The product hue was APHA50.

The reaction product was analyzed by liquid chromatography using the following columns, eluent and detector. Column: Merck Licross Fur 100 RP-18 (5μ
m), 250 mm × 4 mmφ Eluent: Gradient method using the following solutions A and B Solution A: 0.1 M NaClO ₄ in CH ₃ CN / water = 30/70 (vol / vol) Solution B: CH ₃ CN 100 % Detector: UV 260nm hue is 5% solids, acetonitrile / water = 50/50 (vo
1 / vol) solution, compared to an APHA standard.

Example 2 Using the same equipment as in Example 1, salicylic acid (content 9
120.0 g of 9.0% or more (manufactured by Wako Pure Chemical Industries) and 60.0 g of lauric acid (Lunac L-98 manufactured by Kao Corporation) were weighed, and heated to 60 ° C. in a temperature-controllable oil bath with stirring. 60
After reaching ℃, 188.2 g of lauric chloride was added dropwise over about 20 minutes. Thereafter, ripening was carried out under a nitrogen flow and dehydrochlorination was carried out under reduced pressure in the same manner as in Example 1. As a result of quantification by liquid chromatography, o-lauroyloxybenzoic acid was obtained in a yield of 95.0%. The product hue was APHA60.

Examples 3 to 7: Influence of carboxylic acid species Under the same equipment and conditions as in Example 2, sodium p-hydroxybenzoate (same as in Example 1), carboxylic acid halide and carboxylic acid shown in Table 1 The acid was used to confirm the reactivity.
The results are summarized in Table 1.

[0036]

[Table 1]

Note) * 1: Equivalent weight based on the effective amount of sodium p-hydroxybenzoate * 2: Calculated by the following formula.

[0038]

(Equation 1)

Examples 8 to 9: Influence of counter ion The reaction was carried out under the same conditions as in Example 1 except that the counter ion of p-hydroxybenzoic acid was changed as shown in Table 2. The results are summarized in Table 2.

[0040]

[Table 2]

Note) * 1: Based on p-hydroxybenzoate * 2: Calculated by the same formula as in Table 1.

Examples 10 to 13: Kinds of hydroxybenzoic acid Using 2,4-dihydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid as hydroxybenzoic acid, the addition molar ratio of lauric chloride was determined. The reaction was carried out under the same conditions as in Example 1 except that the reaction was changed as shown in FIG. The results are summarized in Table 3.

[0043]

[Table 3]

Note) * 1: molar ratio of hydroxybenzoic acid to hydroxy group * 2: average esterification rate of hydroxyl group of hydroxybenzoic acid (%) * 3: esterification degree in one molecule of each hydroxybenzoic acid It was calculated from the conversion rate.

Examples 14 to 20: Effect of acylating agent species 2,4-dihydroxybenzoic acid and 3,4,5-trihydroxybenzoic acid as hydroxybenzoic acid, acetic anhydride, capric acid as acylating agents Chloride, capric anhydride, and a carboxylic acid having a carboxylic acid residue of an acylating agent were used as the carboxylic acid. Using the same equipment as in Example 1, weigh the same weight of the carboxylic acid shown in Table 4 with respect to 1.0 mol of hydroxybenzoic acid shown in Table 4, and bring the temperature to 80 ° C. in a temperature-controllable oil bath while stirring. Heated. After reaching 80 ° C., the amount of the acylating agent shown in Table 4 was added dropwise over about 20 minutes. Nitrogen gas was supplied at a supply rate of about 0.5 liter / min throughout the reaction from before the addition. Aging is performed in the example using capric acid chloride, after dropping, aging at 80 ° C. for 5 hours,
The pressure was gradually reduced to 100 Torr while maintaining the temperature at ° C., and the hydrochloric acid was removed over 1 hour. In Examples using acetic anhydride and capric anhydride, aging was carried out at 80 ° C. for 6 hours after completion of the dropwise addition. In each case, quantification was performed by liquid chromatography analysis. The results are summarized in Table 4.

[0046]

[Table 4]

Note) * 1: Hydroxy group of acylating agent / hydroxybenzoic acid * 2: Average esterification rate of hydroxyl group of hydroxybenzoic acid * 3: Degree of esterification in 1 minute of each hydroxybenzoic acid from esterification rate Was calculated.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification code FI C07C 69/52 C07C 69/52 69/58 69/58 69/612 69/612 69/614 69/614 69/62 69/62 69/67 69/67 69/773 69/773 233/47 233/47 (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 69/157-69/773 C07C 67/12-67/14 CA (STN) WPI / L (QUESTEL)

Claims (6)

(57) [Claims] 1. A compound of the general formula (1) [Wherein, M ¹ and M ^{2 represent a} hydrogen atom or an alkali metal, alkaline earth metal, ammonium, substituted ammonium or quaternary ammonium, and M ¹ and M ² may be the same or different. m: represents the number of 1 to 3. The hydroxybenzoic acid represented by the general formula (2) is reacted with an acylating agent, or a mixture thereof. [Wherein, M ¹ and M ² have the same meanings as described above. R ¹ : a linear or branched alkyl or alkenyl group having ^{1 to} 21 carbon atoms, which may be substituted with a halogen and may have an ester group, an amide group, an ether group or a phenylene group inserted, or A straight-chain or branched-chain alkyl group or alkenyl group which may be unsubstituted or substituted with a halogen having 1 to 22 carbon atoms and which may have an ester group, an amide group, an ether group or a phenylene group inserted therein, or a halogen. Represents a phenyl group which may be substituted. h: Indicates the number of 1 to 3. i: Indicates the number obtained by subtracting h from m. Here, m has the same meaning as described above. In producing the acyloxybenzoic acid or a salt thereof or a mixture thereof represented by the general formula (3): [Wherein, R ² : a linear or branched alkyl group having 1 to 21 carbon atoms, which may be substituted with a halogen and may have an ester group, an amide group, an ether group or a phenylene group inserted therein, or An alkenyl group, or a straight-chain or branched-chain alkyl group which may be unsubstituted or substituted with 1 to 22 carbon atoms, may be substituted with halogen, and may have an ester group, an amide group, an ether group or a phenylene group inserted. It represents an alkenyl group or a phenyl group which may be substituted with halogen. The method for producing acyloxybenzoic acid or a salt thereof, wherein the reaction is carried out in the presence of a carboxylic acid represented by the formula: 2. An acylating agent represented by the general formula (4): [Wherein, R ¹ has the same meaning as described above. X: represents a halogen atom. Or a carboxylic acid halide represented by the general formula (5): [Wherein, R ¹ has the same meaning as described above. R ^3: 1 to 21 carbon atoms, may be substituted by halogen, an ester group, an amide group, a linear optionally an ether group or a phenylene group is inserted or branched chain alkyl or alkenyl group or, A straight-chain or branched-chain alkyl group or alkenyl group which may be unsubstituted or substituted with a halogen having 1 to 22 carbon atoms and which may have an ester group, an amide group, an ether group or a phenylene group inserted therein, or a halogen. Represents a phenyl group which may be substituted, and may be the same as or different from R ¹ . The method for producing acyloxybenzoic acid or a salt thereof according to claim 1, wherein the carboxylic acid anhydride is represented by the formula: 3. A carboxylic acid represented by the general formula (3):
The method for producing acyloxybenzoic acid or a salt thereof according to claim 1 or 2, which is a linear or branched fatty acid having 2 to 14 carbon atoms. 4. A carboxylic acid halide represented by the general formula (4) or a carboxylic acid anhydride represented by the general formula (5):
The method for producing acyloxybenzoic acid or a salt thereof according to claim 2 or 3, wherein the method has a linear or branched fatty acid residue having 2 to 14 carbon atoms. 5. A carboxylic acid represented by the general formula (3):
The acyloxy according to any one of claims 2 to 4, which has a carboxylic acid halide represented by the general formula (4) or a carboxylic acid residue of a carboxylic anhydride represented by the general formula (5). A method for producing benzoic acid or a salt thereof. 6. A carboxylic acid represented by the general formula (3):
The acyloxybenzoic acid according to any one of claims 1 to 5, wherein the hydroxybenzoic acid represented by the general formula (1) or a salt thereof is used in an amount of 0.05 to 20 parts by weight based on 1 part by weight. Method for producing salt.