Method for producing anthracene-9-carboxylic acid or salt thereof, and chemical composition

Abstract

[Problem] To provide: a chemical composition containing anthracene-9-carboxylic acid and a specific by-product, the composition being friendly to the human body and the environment; and a method for producing the same. The chemical composition is obtained through a reaction system in which: the generation of 9,10-anthraquinone, which is an undesirable by-product, is suppressed; an aliphatic compound having a low boiling point is not used as an additive or a scavenger; and a heavy metal, a transition metal or the like is not used. [Solution] This one method for producing one anthracene-9-carboxylic acid includes a first reaction step of reacting 9-anthraldehyde, an oxidizing agent comprising chlorite, an aliphatic compound having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds, and an acidic compound in a non-polar solvent or in a mixed solvent of a polar solvent and water. Due to this configuration, a chemical composition containing anthracene-9-carboxylic acid (x) and a specific by-product (y) is obtained.

Description

Method for producing anthracene-9-carboxylic acid or its salt, and chemical composition

[0001] The present invention relates to a method for producing anthracene-9-carboxylic acid or a salt thereof, and to a chemical composition.

[0002] Anthracene-9-carboxylic acid is a very useful chemical product as a functional material widely used, for example, as a chemical component in various electrical appliances. Conventionally, techniques for producing anthracene-9-carboxylic acid by a thermal reaction in a nonpolar organic solvent in the presence of an alkali metal hydroxide have been disclosed (Patent Documents 1 and 2). Another method has been disclosed in which anthracene-9-carboxylic acid can be synthesized by oxidizing 9-anthraldehyde (also referred to as "9-anthracenealdehyde"; hereinafter, "9-anthraldehyde" will be used uniformly in this application) using a specific chromium (Cr) complex oxidizing agent (Non-Patent Document 2). Yet another method has been disclosed in which anthracene-9-carboxylic acid is produced by oxidizing anthracene using a compound of a heavy metal such as manganese (Mn) or chromium (Cr) (Non-Patent Document 3).

[0003] Japanese Patent Publication No. 2002-187867 Japanese Patent Publication No. 2004-018391 Chinese Patent Application Publication No. 113831237

[0004] Helv. Chim. Acta. , vol. 2, p. 482 (1919) Synthetic Communications 10(12), p. 951-956 (1980) Bull. Chem. Soc. Japan, vol. 62, p. 545 (1989) Tetrahedron 69(42), 8929-8935, 2013 Russ. Phys. Chem. Soc. 1906, 38, 355, 482, 540, 547

[0005] However, the present inventors have confirmed that even if any of the above-mentioned conventional techniques is adopted, at least one of the following problems (1) to (4) arises, making it difficult to put the techniques into industrial practical use.

[0006] (1) A relatively large amount of the raw material, 9-anthraldehyde, remains unreacted. Alternatively, the conversion rate to anthracene-9-carboxylic acid or the yield of anthracene-9-carboxylic acid during the reaction is low. (2) A relatively large amount or quantitative production of the undesired by-product, 9,10-anthraquinone, is produced.

[0007] (3) In particular, according to the above-mentioned Non-Patent Documents 1 and 2, the burden of post-treatment of heavy metals or transition metals (e.g., chromium or manganese) that may be harmful to the human body and the environment is imposed, and application of the method to various electrical products regulated by the RoHs / REACH regulations, etc., becomes extremely difficult.

[0008] (4) When a low-boiling aliphatic compound is used as an additive or scavenger in the reaction process, industrial use is difficult in consideration of safety to the human body and environmental impact.

[0009] Therefore, it can be said that the development of a technology for safely, simply, and industrially advantageously producing the target substance, anthracene-9-carboxylic acid, without using a heavy metal or transition metal oxidation catalyst, and without using a low-boiling point additive or scavenger, while realizing a high reaction conversion rate and yield, is still in progress.

[0010] The present inventors have carefully examined the above-mentioned patent and non-patent documents, and through follow-up experiments, have recognized the above-mentioned technical problems, and have embarked on research and development of a new method for producing anthracene-9-carboxylic acid that can overcome these problems. In order to solve the problems that anthracene-9-carboxylic acid, the target substance of the present invention, has the property of being easily decarboxylated to anthracene, and that it is relatively easily converted to 9,10-anthraquinone depending on the reaction process, the present inventors have analyzed various experimental results and conducted repeated trial and error.

[0011] As a result, the present inventors discovered a method for producing anthracene-9-carboxylic acid that can produce the following unique effects (i) to (v) by introducing a certain unique aliphatic compound as an additive or scavenger in the reaction process. The present inventors determined that if at least two of the effects (i) to (v) could be achieved, superiority would be achieved over the prior art known to the inventors, and conducted further research and analysis. (i) A very high yield of anthracene-9-carboxylic acid can be achieved. (ii) The target substance, anthracene-9-carboxylic acid, can be produced from the raw material, 9-anthraldehyde, with a very high reaction conversion rate. (iii) The unwanted by-product, 9,10-anthraquinone, is not likely to be produced. (iv) The reaction process does not use highly volatile aliphatic compounds that may have adverse effects on the human body and the environment. (v) The reaction process does not use metal oxidizers or metal catalysts made of heavy metals, transition metals, or the like that may have adverse effects on the human body and the environment.

[0012] Furthermore, when the present inventors analyzed the production method in detail, they found that by specifying the type of oxidizing agent used in the reaction process, a very small amount of a specific by-product is contained in addition to the target substance anthracene-9-carboxylic acid that is finally obtained.

[0013] As a result of further analysis and investigation of the by-products described above, the present inventors have identified the by-products as being represented by the following general formula (1): In the following general formula (1), X represents a chlorine atom and / or a bromine atom.

[0014]

[0015] As described above, it has become clear that anthracene-9-carboxylic acid can be obtained with high certainty by employing a unique chemical reaction that has never been seen before, as far as the present inventors are aware, using a specific aliphatic compound and 9-anthraldehyde as a raw material (also referred to as a starting material; hereinafter, collectively referred to as a "raw material"). In addition to the above facts, the present inventors have also focused on the specificity of a chemical composition (reaction mixture) containing a certain characteristic product that is produced by employing this chemical reaction, thereby completing the present invention.

[0016] One chemical composition of the present invention contains anthracene-9-carboxylic acid and a compound represented by the following general formula (1):

[0017] (In general formula (1), X represents a chlorine atom and / or a bromine atom.)

[0018] In addition, in another chemical composition of the present invention, the content of the anthracene-9-carboxylic acid is, in area percentage, 86 area % or more and 99 area % or less, as determined by HPLC (high performance liquid chromatography), and the content of the compound represented by general formula (1) is, in area percentage, 0.001 area % or more and 10 area % or less, as determined by the HPLC analysis.

[0019] Each of the above-mentioned inventions is a chemical composition containing the compound represented by the above-mentioned general formula (1). As far as the inventors know, there is no prior art method for producing anthracene-9-carboxylic acid using 9-anthraldehyde as a raw material, in which the compound represented by the above-mentioned general formula (1) is produced, for example, as a by-product in the reaction mixture.

[0020] In particular, when the content of the anthracene-9-carboxylic acid as determined by HPLC (high performance liquid chromatography) analysis is 86 area % or more and 99 area % or less in area percentage, and the content of the compound represented by general formula (1) as determined by HPLC analysis is 0.001 area % or more and 10 area % or less in area percentage, in a chemical composition (reaction mixture) containing anthracene-9-carboxylic acid as a main component, high purity of anthracene-9-carboxylic acid in the chemical composition and / or a high yield of anthracene-9-carboxylic acid in the production process are realized.

[0021] Furthermore, one method for producing anthracene-9-carboxylic acid according to the present invention includes a first reaction step of mixing 9-anthraldehyde, an oxidizing agent, an aliphatic compound having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds (hereinafter, for convenience, also referred to as "predetermined aliphatic compound"), and an acidic compound in a non-polar solvent or a mixed solvent of a polar solvent and water.

[0022] In this production method, a mixed solvent of a non-polar solvent and water, or a mixed solvent of a polar solvent and water, is used, in which at least the following (SL1), (SL2), and (SL3) are mixed. As a result, this production method can achieve a higher reaction conversion rate to anthracene-9-carboxylic acid and / or a higher yield of the anthracene-9-carboxylic acid compared to conventional techniques. (SL1) The aliphatic compound containing one or more carbon-carbon double bonds and having a boiling point of 120° C. or higher; (SL2) An oxidizing agent; and (SL3) An acidic compound.

[0023] The main reason why the above-mentioned higher reaction conversion rate to anthracene-9-carboxylic acid and / or the higher yield of anthracene-9-carboxylic acid can be realized is the use of a specific aliphatic compound in the first reaction step. The present inventors have found that the aliphatic compound having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds can be a highly reliable scavenger of by-products that may be generated in the first reaction step. In particular, when the above-mentioned "oxidizing agent" is chlorous acid or a chlorite, the aliphatic compound can be used to capture hypochlorous acid (HClO) generated as the by-product. ２It is noteworthy that the present inventors have found that the scavenging rate of hypochlorous acid as a by-product is 95% or more and 99.99% or less, as determined by experiments by the present inventors.

[0024] In addition, when the above-mentioned "oxidizing agent" is chlorous acid or a chlorite, the compound represented by the following chemical formula (2) is produced in the first reaction step, which can be said to be one aspect that represents a characteristic of the above-mentioned method for producing anthracene-9-carboxylic acid.

[0025]

[0026] Here, an example of the first reaction step is shown. Note that the following chemical reaction formula (3), which is an example of the first reaction step, shows an example where the "oxidizing agent" is chlorous acid. Specifically, it is believed that anthracene-9-carboxylic acid can be produced from the raw material 9-anthraldehyde through the following reaction steps (A) to (B) in chemical reaction formula (3).

[0027] (A) Chlorous acid reacts with the raw material 9-anthraldehyde, and chlorite ions attack the aldehyde carbonyl (chemical reaction formula (3) (a) and (b)), producing intermediate species A. (B) After that, the hydrogen group in intermediate species A bonds with the oxygen that bonds with chlorine, and the hydrogen group leaves, forming a double bond between carbon and oxygen (chemical reaction formula (3) (c)), producing anthracene-9-carboxylic acid (chemical substance B) and hypochlorous acid (chemical substance C).

[0028] Furthermore, as a result of further research and analysis into the first reaction step, the present inventors have found something very interesting: for example, when the "oxidizing agent" is chlorous acid or a chlorite, a trace amount of a compound represented by chemical substance D (the same as the compound represented by chemical formula (2)) can be produced almost simultaneously with the reaction of (c) in chemical reaction formula (3) or after the reaction of (c) in chemical reaction formula (3).

[0029]

[0030] Although the mechanism by which the above-mentioned chemical substance D is produced is not yet clear, the present inventors believe that chemical substance D is produced through the following reaction process.

[0031] Specifically, hypochlorous acid (chemical substance C) is generated as a by-product in the first reaction step, albeit in trace amounts, and in an acidic solvent, trace amounts of chlorine molecules (Cl) are generated by the following assumed chemical reaction: ２ ) is thought to be produced. [Chemical reaction formula] 2HOCl → H ２ O+O ２ +Cl ２

[0032] The minute amount of chlorine molecules (Cl ２ The present inventors believe that at least a portion of the anthracene-9-carboxylic acid (chemical substance B) produced in the first reaction step reacts with the anthracene-9-carboxylic acid (chemical substance B) to produce a compound represented by chemical substance D, albeit in a small amount.

[0033] One chemical composition of the present invention is, to the best of the inventor's knowledge, a unique chemical composition that contains anthracene-9-carboxylic acid and the compound represented by the above-mentioned general formula (1). Furthermore, one method for producing anthracene-9-carboxylic acid of the present invention can achieve a higher reaction conversion rate to anthracene-9-carboxylic acid and / or a higher yield of the anthracene-9-carboxylic acid compared to conventional techniques.

[0034] In Example 1, (a) an HPLC diagram of the reaction mixture after the first reaction step, and (b) an HPLC diagram of the purified solid material after the third reaction step. In Example 1, (a) an HPLC diagram of the by-product isolated from the crude solid material after the third reaction step. In Example 1, (b) a proton nuclear magnetic resonance (NMR) diagram of the main product in the crude solid material after the first reaction step. １ (b) proton nuclear magnetic resonance (H-NMR) spectrum of by-products in the crude solid material after the first reaction step. １1H-NMR) spectrum of the main product in the crude solid material after the first reaction step in Example 1. (a) IR spectrum (infrared absorption spectrum) of the main product in the crude solid material after the first reaction step, and (b) IR spectrum (infrared absorption spectrum) of the by-product in the crude solid material after the first reaction step in Example 1. １３ 1 is a diagram of the C-13 nuclear magnetic resonance (C-NMR) spectrum of the by-product in the crude solid material after the first reaction step in Example 1. １３ 4 and 5. (a) is a partial enlarged view of FIG. 4, and (b) is a partial enlarged view of FIG. 5.

[0035] First Embodiment A method for producing anthracene-9-carboxylic acid and a chemical composition containing anthracene-9-carboxylic acid according to this embodiment will be described below.

[0036] <Production Process of Anthracene-9-carboxylic Acid or a Salt Thereof, and Other Chemical Compositions> Anthracene-9-carboxylic acid and other chemical compositions of the present embodiment can be produced based on the reaction mechanisms shown in the chemical reaction formulas (Chemical Formula 1) and (A) to (B) already described, and an example of a specific process is as follows.

[0037] First, 9-anthraldehyde, which is a raw material for producing anthracene-9-carboxylic acid, can be obtained by a known method for obtaining or producing it. For example, it is commercially available, or it can be obtained relatively easily by using anthracene as a raw material through the Vilsmeier-Haack reaction or the like.

[0038] In this embodiment, a first reaction step is carried out in which the above-mentioned 9-anthraldehyde, an oxidizing agent, a predetermined aliphatic compound, and an acidic compound are mixed (a typical example is suspension mixing) in a mixed solvent of a non-polar solvent and water or a mixed solvent of a polar solvent and water.

[0039] Specifically, the predetermined aliphatic compound that can be employed in this embodiment is an aliphatic compound having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds. By employing such an aliphatic compound, it is possible to highly reliably suppress the problems of large amounts of 9,10-anthraquinone, a by-product that is undesirable from the viewpoint of highly reliably obtaining the target substance, anthracene-9-carboxylic acid, being produced, and / or large amounts of unreacted 9-anthraldehyde remaining. As a result, it is possible to highly reliably increase the reaction conversion to anthracene-9-carboxylic acid and / or the yield of the anthracene-9-carboxylic acid.

[0040] In other words, if a known substance called a scavenger, such as amylene, hydrogen peroxide, sulfamic acid, or resorcinol, is used instead of the aliphatic compound having the above-mentioned characteristics, a large amount of 9,10-anthraquinone is produced and / or a large amount of 9-anthraldehyde remains unreacted, resulting in a significant decrease in the yield of anthracene-9-carboxylic acid.

[0041] A representative example of the above-mentioned predetermined aliphatic compound in this embodiment is terpenes. Specific examples of the aliphatic compound include at least one selected from the group consisting of (+)-limonene, (-)-limonene, terpinolene, β-myrcene, prenol (3-methyl-2-buten-1-ol), vitamin A, farnesol, squalene, and geraniol. Among the above-mentioned examples, (+)-limonene is an oxidizing agent that can be used to oxidize hypochlorous acid (HClO ), which is generated as a by-product in the first reaction step when the "oxidizing agent" described below is chlorous acid or a chlorite salt. ２ This is a very preferred embodiment because it can serve as a highly accurate capture agent for the hydroxybenzoates.

[0042] The amount of the aliphatic compound used is not particularly limited as long as the effects of this embodiment are not substantially impaired. A typical amount of the aliphatic compound used relative to 1 mole of the raw material 9-anthraldehyde is 0.5 moles or more and 10 moles or less. Within the above-mentioned range, using an amount of the aliphatic compound of 0.5 moles (more preferably 1.2 moles) or more is a preferred embodiment from the viewpoint of obtaining the target substance anthracene-9-carboxylic acid with a high degree of certainty and suppressing a decrease in the reaction rate of the first reaction step. On the other hand, within the above-mentioned range, using an amount of the aliphatic compound of 10 moles (more preferably 2 moles) or less is a preferred embodiment from the viewpoint of obtaining the target substance anthracene-9-carboxylic acid with a high degree of certainty and suppressing the production of undesirable by-products such as 9,10-anthraquinone, and / or reducing the processing load after the first reaction step (in other words, reducing the economic burden).

[0043] Representative examples of the oxidizing agent in this embodiment are chlorous acid, bromous acid, chlorite, and / or bromite. The use of chlorite and / or bromite, which have high chemical stability, is a preferred embodiment from the viewpoint of enhancing the safety and reliability of the production process. Furthermore, from the viewpoint of enhancing the safety and reliability of the production process through the first reaction step, it is a preferred embodiment to use, among chlorites, an alkali metal chlorite (typically, sodium chlorite and / or potassium chlorite) or an alkaline earth metal chlorite (typically, calcium chlorite). In particular, when preparing an aqueous solution of chlorite, the use of an aqueous solution of alkali metal chlorite or an aqueous solution of alkaline earth metal chlorite having a concentration of 25 wt % or less is a particularly preferred embodiment from the viewpoint of enhancing the safety and reliability of the production process.

[0044] Among the examples of the oxidizing agent described above, for example, the amount of chlorite (typically sodium chlorite, potassium chlorite, or calcium chlorite) used is not particularly limited as long as the effects of this embodiment are not substantially impaired. A typical amount of chlorite used relative to 1 mole of the raw material 9-anthraldehyde is 0.5 moles or more and 5 moles or less. Within the above-mentioned numerical range, using an amount of chlorite of 0.5 moles or more is a preferred embodiment from the viewpoint of obtaining the target substance anthracene-9-carboxylic acid with a high degree of certainty and suppressing the production of undesirable by-products such as 9,10-anthraquinone, and / or reducing the processing load after the first reaction step (in other words, reducing the economic burden).

[0045] Examples of polar solvents in this embodiment include at least one alcohol selected from the group consisting of methanol, ethanol, propanol, isopropanol, butanol, isobutanol, ethylene glycol, propylene glycol, 1,3-butylene glycol, and t-butanol. Examples of nonpolar solvents in this embodiment include aromatic hydrocarbons such as toluene, xylene, cumene, and methylnaphthalene; at least one ether selected from the group consisting of tetrahydrofuran, 4-methyltetrahydropyran, diethyl ether, diisopropyl ether, 2-methyltetrahydrofuran, dioxane, and methylphenyl ether; at least one ketone selected from the group consisting of acetone, methyl isobutyl ketone, methyl ethyl ketone, cyclopentanone, and cyclohexanenone; and at least one ester selected from the group consisting of methyl acetate, ethyl acetate, isobutyl acetate, n-propyl acetate, and butyl acetate. A solvent prepared by mixing the above-mentioned polar solvent and the above-mentioned nonpolar solvent with water can also be used.

[0046] Here, it is preferable to use t-butanol among the examples of polar solvents mentioned above, from the viewpoint of being less likely to inhibit the first reaction step of this embodiment or promoting the first reaction step. Furthermore, from the same viewpoint as above, it is preferable to use toluene or ethyl acetate among the examples of nonpolar solvents mentioned above. In addition, the mixing ratio of water is not particularly limited, but from the viewpoint of producing anthracene-9-carboxylic acid, which is the final target substance, with a high degree of certainty in the first reaction step of this embodiment, it is a preferred embodiment that the ratio of water is more than 0 wt % and 80 wt % or less (more preferably 20 wt % or more and 50 wt % or less) of the total solvent.

[0047] In order to achieve exceptional coarseness, the amount of the mixed solvent used in this embodiment is preferably 2 parts by mass or more per part by mass of the raw material 9-anthraldehyde, as long as the effect of this embodiment is not substantially impaired. On the other hand, from the viewpoint of reducing the burden of post-treatment of the used solvent (in other words, from the viewpoint of reducing the economic burden), it is a preferred embodiment to set the amount of the mixed solvent to 50 parts by mass or less per part by mass of the 9-anthraldehyde.

[0048] In the first reaction step, an acidic compound is further mixed as appropriate. It is believed that the acidic compound can play a role in activating the oxidizing agent in the first reaction step. Representative examples of the acidic compound in this embodiment include phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, acetic acid, hydrochloric acid, and sulfuric acid.

[0049] Among the examples of the acidic compound described above, for example, the amount of dihydrogen phosphate used is not particularly limited as long as the effects of this embodiment are not substantially impaired. A typical amount of dihydrogen phosphate used relative to 1 mole of the raw material 9-anthraldehyde is 0.5 moles or more and 5 moles or less. Within the above-mentioned range, using an amount of dihydrogen phosphate of 0.5 moles or more is a preferred embodiment from the viewpoint of obtaining the target substance anthracene-9-carboxylic acid with a high degree of certainty and suppressing a decrease in the reaction rate of the first reaction step. On the other hand, within the above-mentioned range, using an amount of dihydrogen phosphate of 5 moles or less is a preferred embodiment from the viewpoint of obtaining the target substance anthracene-9-carboxylic acid with a high degree of certainty and suppressing the production of undesirable by-products such as 9,10-anthraquinone, and / or reducing the burden of treatment after the first reaction step (in other words, reducing the economic burden).

[0050] Furthermore, it is preferable to appropriately manage the reaction temperature in the first reaction step from the viewpoints of adjusting the reaction rate and / or obtaining the target substance, anthracene-9-carboxylic acid, with a high degree of certainty while suppressing the production of undesirable by-products such as 9,10-anthraquinone. From the above viewpoints, adjusting the reaction temperature to a range of −10° C. or higher and 60° C. or lower (more preferably, 5° C. or higher and 60° C. or lower) is a preferred aspect of this embodiment. In addition, the reaction time can be appropriately adjusted depending on the type of the solvent and / or the predetermined aliphatic compound used, but a typical reaction time is 1 hour or higher and 24 hours or lower.

[0051] Incidentally, in order to recover with high certainty the target substance, anthracene-9-carboxylic acid, from the reaction mixture in the acidic solution obtained after the first reaction step of this embodiment, the second reaction step and the third reaction step may be carried out.

[0052] In the second reaction step of this embodiment, a sufficient amount of a reducing agent, such as sodium hydrogen sulfite, sodium sulfite, or sodium thiosulfate, is added to the acidic solution. The solution is then concentrated under reduced pressure, and the crude solid material is collected by filtration. In the third reaction step, a nonpolar solvent (e.g., toluene, xylene, ethyl acetate, butyl acetate, diethyl ether, or 4-methyltetrahydropyran) and a basic aqueous solution (e.g., aqueous sodium hydrogen carbonate, aqueous sodium carbonate, aqueous potassium carbonate, aqueous sodium hydroxide, or aqueous potassium hydroxide) are added to the crude solid material. As a result, the salt of anthracene-9-carboxylic acid is extracted into the aqueous layer, and then separated using an organic solvent (e.g., a nonpolar solvent such as toluene, xylene, ethyl acetate, butyl acetate, diethyl ether, or 4-methyltetrahydropyran), allowing the separation and removal of by-products such as 9,10-anthraquinone and the starting material, 9-anthraldehyde. An acidic solution, such as concentrated hydrochloric acid or concentrated sulfuric acid, is then added to the aqueous layer to effect acidification, and the resulting crystals are collected by filtration. The crystals are a chemical composition containing anthracene-9-carboxylic acid, which is the target substance of this embodiment. Therefore, it has become clear that by performing the first reaction step, the above-mentioned reaction mixture of this embodiment can be realized to contain at least the anthracene-9-carboxylic acid or a salt thereof.

[0053] In one method for producing anthracene-9-carboxylic acid according to the present embodiment, which uses 9-anthraldehyde as a raw material, a compound represented by the following general formula (1) can be contained in the reaction mixture by employing the first reaction step described above. In the following general formula (1), X represents a chlorine atom and / or a bromine atom.

[0054]

[0055] Another advantageous feature of the production method of this embodiment is that only reaction processes that are friendly to the human body and the environment are used, in which the content of heavy metals or transition metals, such as palladium (Pd), platinum (Pt), manganese (Mn), chromium (Cr), silver (Ag), copper (Cu), or selenium (Se), in the reaction mixture after the first reaction step is less than 0.01 mass%. It is worth noting that the content of the heavy metals or transition metals that may be contained in the reaction mixture obtained after not only the first reaction step but also the second and third reaction steps is less than 0.01 mass%.

[0056] <Examples> The above-described embodiment will be specifically described through the following examples, but the scope of the present invention and the embodiments are not limited by the description of the examples. Note that, in Examples 1 to 4 described below, treatments based on the first to third reaction steps of the above-described embodiment were carried out. In addition, in Comparative Examples 1 to 4 described below, a conventional method for producing anthracene-9-carboxylic acid using the Pinnic oxidation reaction was adopted.

[0057] Example 1 In a 100 mL (milliliter) reaction vessel equipped with a stirrer, a 20°C mixed solvent consisting of 10 mL of t-butanol and 5 mL of pure water, 1.03 g (0.005 mol) of 9-anthraldehyde as a raw material, 0.82 g (0.006 mol) of (+)-limonene as an example of the predetermined aliphatic compound of the first embodiment, 1.96 g (0.0055 mol) of a 25 wt % aqueous sodium chlorite solution as an example of the oxidizing agent of the first embodiment, and 0.936 g (0.006 mol) of sodium dihydrogen phosphate dihydrate as an example of the acidic compound of the first embodiment were mixed with stirring for about 1 hour. This corresponds to the first reaction step of the first embodiment.

[0058] The liquid reaction mixture after the first reaction step of this example was analyzed using HPLC (high performance liquid chromatography). As a result, as will be described in detail later, the reaction conversion rates of the raw material 9-anthraldehyde, the target substance anthracene-9-carboxylic acid, the by-product 9,10-anthraquinone, and other products in the reaction mixture were examined. Table 1, which will be shown later, shows the results. In Table 1, "9-AC" means anthracene-9-carboxylic acid, and "9-AA" means 9-anthraldehyde. In Table 1, "QN" means 9,10-anthraquinone.

[0059] In this example, sodium hydrogen sulfite, which is an example of the reducing agent of the first embodiment, and water were added to the liquid reaction mixture after the first reaction step. The mixture was then concentrated under reduced pressure to remove t-butanol. The residue was then filtered to obtain a crude solid material. This corresponds to the second reaction step in the first embodiment.

[0060] Furthermore, in this example, ethyl acetate and a 10 wt % aqueous solution of sodium bicarbonate were added to the crude solid material obtained by the second reaction step, followed by washing. Subsequently, concentrated hydrochloric acid was added to the washed aqueous layer, followed by acidification and filtration, yielding 1.02 g of a purified solid material (chemical composition). This corresponds to the third reaction step in the first embodiment. The finally obtained chemical composition was analyzed using HPLC to determine its purity in terms of area percentage. As a result, the inventors confirmed that the purity of anthracene-9-carboxylic acid contained in the chemical composition was 99.6% and that the yield was 91.8 mol%, both of which are extremely excellent figures.

[0061] [Results of Various Analyses] Here, the results of various analyses of the chemical composition containing anthracene-9-carboxylic acid in high yield and high purity obtained in this example will be described.

[0062] Interestingly, when the chemical composition of this example was analyzed using various measurement methods, it was revealed that by employing the first reaction step of this example, a chemical composition containing a compound represented by the following chemical formula (2) was obtained in the reaction mixture, which, as far as the inventors know, has not been found in conventional by-products.

[0063] Therefore, regarding the results of various analyses, in particular, the process by which the above-mentioned unique compound obtained by employing the first reaction step was identified will be explained.

[0064] FIG. 1A shows (a) an HPLC (high performance liquid chromatography) diagram of the reaction mixture after the first reaction step, and (b) an HPLC diagram of the purified solid material after the third reaction step in this example. FIG. 1B shows an HPLC diagram of the by-product isolated from the purified solid material after the third reaction step in this example. FIG. 2 shows (a) a proton nuclear magnetic resonance (NMR) diagram of the main product in the purified solid material after the third reaction step in this example. １ (b) proton nuclear magnetic resonance (H-NMR) spectrum of the by-product in the purified solid material after the third reaction step. １ 1H-NMR) spectrum. Also, FIG. 3 shows (a) an IR spectrum (infrared absorption spectrum) of the main product in the purified solid material after the third reaction step in this example, and (b) an IR spectrum (infrared absorption spectrum) of the by-product in the purified solid material after the third reaction step. In FIG. 3, characteristic absorption peaks are shown in square frames for ease of understanding. Also, FIG. 4 shows the C-13 nuclear magnetic resonance ( １３ 5 shows the C-13 nuclear magnetic resonance (C-NMR) spectrum of the by-product in the purified solid material after the third reaction step in this example. １３1A and 1B are diagrams of C-NMR spectra. Also, FIG. 6 is a partial enlargement (a) of FIG. 4 and a partial enlargement (b) of FIG. 5. In FIG. 1A, "9-AC" means anthracene-9-carboxylic acid, and "9-AA" means 9-anthraldehyde. Also, "QN" in FIG. 1A means 9,10-anthraquinone.

[0065] First, as shown in FIG. 1A(a), HPLC (high performance liquid chromatography) analysis results indicate that the target substance, anthracene-9-carboxylic acid, is produced in the crude solid material obtained after the first reaction step, with the production of by-products sufficiently suppressed. Regarding the identification of the substance showing the strongest peak in FIG. 1A(a), in addition to the HPLC analysis, the inventors have confirmed that the analytical results of the main product of the crude solid material agree with the analytical results of anthracene-9-carboxylic acid, a reference substance for which the substance has already been identified, based on the results of various analyses described below. Similarly, for "9-AA" and "QN" shown in FIG. 1A(a), each substance was identified by comparison with the respective identified reference substances.

[0066] Furthermore, as shown in FIG. 1A(b), the analysis results revealed that the purified solid substance (the chemical composition of this example) after the third reaction step contained almost no by-products other than "9-AC," i.e., anthracene-9-carboxylic acid with extremely high purity was produced.

[0067] Next, in this example, products (by-products) other than anthracene-9-carboxylic acid (9-AC) were isolated from the purified solid material after the third reaction step, and the results of HPLC analysis are shown in Figure 1B. As a result, it was found that the isolated substance (by-product) was a substance ("x" in Figure 1B) of extremely high purity (99% or more, more narrowly, more than 99.5%). Note that the other trace substance ("y" in Figure 1B) is thought to be 9,10-anthraquinone.

[0068] Here, the present inventors have conducted repeated analyses and investigations to identify the above-mentioned isolated substance ("x" in Figure 1B), and as a result, have discovered something very interesting. Specifically, the proton nuclear magnetic resonance (NMR) of a reference substance (i.e., a compound represented by the above-mentioned chemical formula (2)) in which the 10-position of the anthracene skeleton of anthracene-9-carboxylic acid is chlorinated using N-chlorosuccinimide (NSC) was measured. １ The inventors compared the H-NMR spectrum of the isolated substance ("x" in FIG. 1B) with the spectrum shown in FIG. 2(b) for the isolated substance, and confirmed that they were consistent. Therefore, the inventors found that the isolated substance was highly likely to be the compound (9-AC-Cl) represented by the above-mentioned chemical formula (2).

[0069] Furthermore, the present inventors performed IR spectrum analysis and C-13 nuclear magnetic resonance analysis shown in Figures 2(a), 3(a), 4, and 6(a) on anthracene-9-carboxylic acid (9-AC), which is the target substance of this example, and also performed IR spectrum analysis and C-13 nuclear magnetic resonance analysis shown in Figures 3(b), 5, and 6(b) on the compound (9-AC-Cl) represented by the above-mentioned chemical formula (2).

[0070] As a result, the inventors confirmed that there was no contradiction between the analytical results, which indicate that the substance derived from the results shown in Figures 2(a), 3(a), 4, and 6(a) is anthracene-9-carboxylic acid (9-AC), and the results shown in Figures 2(b), 3(b), 5, and 6(b) is the compound (9-AC-Cl) represented by the above-mentioned chemical formula (2). Based on the above-mentioned experimental results, the inventors identified the above-mentioned isolated substance ("x" in Figure 1B) as the compound represented by the above-mentioned chemical formula (2).

[0071] As described above, this example demonstrates that the target compound, anthracene-9-carboxylic acid, can be obtained from the raw material, 9-anthraldehyde, in a very high yield and with a high conversion rate. In addition, this example demonstrates that the compound (9-AC-Cl), which can be considered a unique by-product, represented by the above-mentioned chemical formula (2), can be obtained.

[0072] Examples 2 to 4 In Examples 2 to 4, reaction steps corresponding to the first to third reaction steps were carried out under the same conditions as in Example 1, except that prenol, geraniol, or farnesol was used as the "predetermined aliphatic compound" instead of (+)-limonene, which was used as the "predetermined aliphatic compound" in Example 1 above. As a result, the reaction conversion rates from the raw material 9-anthraldehyde to the target product anthracene-9-carboxylic acid, the by-product 9,10-anthraquinone, and other products in the reaction mixture were investigated. Table 1 below shows these results, along with the results of Example 1.

[0073]

[0074] As described above, as shown in Table 1, it was found that the target substance, anthracene-9-carboxylic acid, could be obtained from the raw material, 9-anthraldehyde, with a very high yield and a high reaction conversion rate in Examples 1 to 4. Furthermore, it was found that the compound (9-AC-Cl), which can be considered a unique by-product and is represented by the above-mentioned chemical formula (2), was obtained in Examples 2 to 4, as in Example 1.

[0075] (Comparative Examples 1 to 5) For comparison with the above-mentioned examples, the inventors conducted comparative experiments using the following scavengers or additives instead of the "predetermined aliphatic compound." Specific conditions for Comparative Examples 1 to 5 are as follows:

[0076] In Comparative Examples 1 to 5, a reaction step corresponding to the first reaction step was carried out under the same conditions as in Example 1, except that the "predetermined aliphatic compound" was not present or that amylene, sulfamic acid, hydrogen peroxide, or resorcinol was used as a scavenger or additive instead of the "predetermined aliphatic compound." As a result, the reaction conversion rates from the raw material 9-anthraldehyde to the target product anthracene-9-carboxylic acid, the by-product 9,10-anthraquinone, and other products in the reaction mixture were investigated. Table 2 below shows the results of Comparative Examples 1 to 5.

[0077]

[0078] As a result, when comparing the examples using "predetermined aliphatic compounds" such as Examples 1 to 4 with Comparative Examples 1 to 5, it was revealed that, with the exception of amylene, the conversion rate of the reaction from the raw material 9-anthraldehyde to the target substance anthracene-9-carboxylic acid in each Comparative Example was significantly low. Furthermore, it was confirmed that the total amount of by-products ("QN," "9-AA," and "others" in the table) when amylene was used was more than 10% higher than that of "farnesol," which had the lowest conversion rate among Examples 1 to 4.

[0079] In addition to the above-described Examples 1 to 4, other experiments have shown that anthracene-9-carboxylic acid (9-AC) can be produced in very high yield and / or with very high reaction conversion by employing the above-described embodiment.

[0080] Specifically, the HPLC analysis revealed that the content of anthracene-9-carboxylic acid (9-AC) was 86 area % or more (more narrowly, 90 area % or more, even more narrowly, 95 area % or more) and 99.99 area % or less. Furthermore, the HPLC analysis revealed that the content of the compound (9-AC-Cl) represented by the above chemical formula (2) was 0.001 area % or more and 10 area % or less (more narrowly, 0.001 area % or more and 5 area % or less, even more narrowly, 0.001 area % or more and 3 area % or less).

[0081] Furthermore, according to Examples 1 to 4 and other multiple experiments, the reaction conversion rate was high, and it is worth noting that the content (residual amount) of unreacted 9-anthraldehyde (i.e., remaining in the reaction vessel), which is the raw material, as determined by HPLC analysis, was 5 area % or less (more narrowly, 3 area % or less, and even more narrowly, 2 area % or less) in terms of area percentage.

[0082] Furthermore, it is worth noting that, according to Examples 1 to 4 and other multiple experiments, the reaction conversion rate was high, and therefore the content of the undesirable by-product 9,10-anthraquinone, as determined by HPLC analysis, was 5 area % or less (more narrowly, 3 area % or less). In particular, when (+)-limonene was used as the aliphatic compound (predetermined aliphatic compound) having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds, the content of the undesirable by-product 9,10-anthraquinone was found to be a very low value of 1.55 area % or less.

[0083] Therefore, based on the above embodiment and Examples 1 to 4, the chemical composition after at least the third reaction step in the above embodiment can be described as follows:

[0084] That is, one example of a chemical composition based on the above-described embodiment and Examples 1 to 4 is a chemical composition containing anthracene-9-carboxylic acid and a compound that appears as peak (x) in FIG. 1A(a) in HPLC (high performance liquid chromatography) analysis.

[0085] The above-described embodiments and examples do not limit the present invention in any way. Modifications within the scope of the present invention, including other combinations of the above-described embodiments and examples, are also included in the scope of the claims.

[0086] The method for producing anthracene-9-carboxylic acid or a salt thereof of the present invention, and the chemical composition of the present invention can be widely used as useful chemical substances or methods for producing them, for materials with a variety of applications (for example, functional materials used in various electrical products or intermediates thereof).

Claims

1. A compound containing anthracene-9-carboxylic acid or a salt thereof, and a compound represented by the following general formula (1), chemical composition. 【Chemistry 1】 (In general formula (1), X represents a chlorine atom and / or a bromine atom.)

2. HPLC (High-Performance Liquid Chromatography) analysis determined that the content of the anthracene-9-carboxylic acid is 86% or more and 99% or less in terms of area percentage, and The content of the compound represented by the general formula (1) as determined by the HPLC analysis is 0.001 area% or more and 10 area% or less in terms of area percentage. The chemical composition according to claim 1.

3. HPLC (High-Performance Liquid Chromatography) analysis determines that the content of the anthracene-9-carboxylic acid is 95% or more and 99.99% or less in terms of area percentage, and The content of the compound represented by the general formula (1) as determined by the HPLC analysis is 0.001 area% or more and 5 area% or less in terms of area percentage. The chemical composition according to claim 1.

4. It further contains 9-anthraldehyde, and HPLC (high-performance liquid chromatography) analysis shows that the content of 9-anthraldehyde is 5% or less by area percentage. The chemical composition according to claim 1 or claim 2.

5. It further contains 9,10-anthraquinone, and HPLC (High-Performance Liquid Chromatography) analysis shows that the content of 9,10-anthraquinone is 5% or less by area percentage. The chemical composition according to claim 1 or claim 2.

6. The content of palladium (Pd), platinum (Pt), manganese (Mn), chromium (Cr), silver (Ag), copper (Cu), or selenium (Se) is less than 0.01% by mass. The chemical composition according to claim 1 or claim 2.

7. The first reaction step involves mixing 9-anthraldehyde, an oxidizing agent, an aliphatic compound having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds, and an acidic compound in a nonpolar solvent or a mixed solvent of a polar solvent and water. The reaction mixture after the first reaction step contains anthracene-9-carboxylic acid and a compound represented by the following general formula (1), A method for producing anthracene-9-carboxylic acid or a salt thereof. 【Chemistry 2】 (In general formula (1), X represents a chlorine atom and / or a bromine atom.)

8. The aliphatic compound is a terpene. A method for producing anthracene-9-carboxylic acid or a salt thereof according to claim 7.

9. The aliphatic compound is at least one selected from the group consisting of (+)-limonene, (-)-limonene, terpinolene, β-myrcene, prenol (3-methyl-2-buten-1-ol), vitamin A, farnesol, squalene, and geraniol. A method for producing anthracene-9-carboxylic acid according to claim 7.

10. The oxidizing agent is chlorous acid or a chlorite salt. A method for producing anthracene-9-carboxylic acid or a salt thereof according to claim 7 or claim 8.

11. The content of palladium (Pd), platinum (Pt), manganese (Mn), chromium (Cr), silver (Ag), copper (Cu), or selenium (Se) in the reaction mixture after the first reaction step is less than 0.01% by mass. A method for producing anthracene-9-carboxylic acid or a salt thereof according to claim 7 or claim 8.

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