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

Technical Field

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

Background Art

[0002] Anthracene-9-carboxylic acid is a very useful chemical product as a functional material widely used, for example, as a chemical member of various electrical products. Conventionally, a technique for producing anthracene-9-carboxylic acid by heating in a non-polar organic solvent in the presence of an alkali metal hydroxide has been disclosed (Patent Documents 1 and 2). Also, as another method, a technique is 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 uniformly used in the present application) using a specific chromium (Cr) complex oxidant (Non-Patent Document 2). Further, as yet another method, an example of producing anthracene-9-carboxylic acid by oxidizing anthracene using a compound of a heavy metal such as manganese (Mn) or chromium (Cr) has also been disclosed (Non-Patent Document 3).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Patent Document 2

Patent Document 3

Non-Patent Documents

[0004]

Non-Patent Document 1

Non-Patent Document 2

[0005] However, the inventors have confirmed that adopting any of the above-mentioned prior arts results in at least one of the following problems (1) to (4), making industrial practical application difficult.

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

[0007] (3) In particular, according to Non-Patent Document 1 or 2 mentioned above, the burden of post-treatment of heavy metals or transition metals (e.g., chromium or manganese) that may harm the human body and the environment will be incurred, and it will be extremely difficult to apply them to various electrical products that are regulated by RoHS / REACH regulations, etc.

[0008] (4) When low-boiling point aliphatic compounds are used as additives or scavengers in the reaction process, industrial use is difficult considering the safety to the human body and the impact on the environment.

[0009] Therefore, the development of a technology to safely and simply produce the target substance, anthracene-9-carboxylic acid, without using heavy metal or transition metal oxidation catalysts, and without using low-boiling-point additives or scavengers, while also achieving high reaction conversion rates and yields and being industrially advantageous, is still in its early stages. [Means for solving the problem]

[0010] The inventors, after carefully examining the aforementioned patent and non-patent documents, recognized the aforementioned technical problems through replication experiments and commenced research and development of a new method for producing anthracene-9-carboxylic acid that could overcome these problems. In order to solve the problems of anthracene-9-carboxylic acid, the target substance of the present invention, being easily converted to anthracene by decarboxylation and being relatively easily converted to 9,10-anthraquinone depending on the reaction process, the inventors analyzed various experimental results and went through repeated trial and error.

[0011] As a result, the inventors have discovered a method for producing anthracene-9-carboxylic acid that can produce the following specific effects (i) to (v) by introducing a certain specific aliphatic compound as an additive or scavenger during the reaction process. The inventors determined that if they could obtain at least several of these effects (i) to (v), they would gain an advantage over the prior art known to them, and so they continued their research and analysis. (i) Very high yields of anthracene-9-carboxylic acid can be achieved. (ii) From the raw material 9-anthraldehyde, the target substance anthracene-9-carboxylic acid can be produced with a very high reaction conversion rate. (iii) To reliably prevent the formation of the unwanted by-product 9,10-anthraquinone. (iv) The reaction process does not use highly volatile aliphatic compounds that could have adverse effects on the human body or the environment. (v) No metal oxidizing agents or metal catalysts consisting of heavy metals or transition metals that may have adverse effects on the human body or the environment are used in the reaction process.

[0012] In addition, when the present inventor analyzed the manufacturing method in detail, it was found that by specifying the type of oxidizing agent used in the reaction process, in addition to the anthracene-9-carboxylic acid of the target substance finally obtained, there is a very small amount of a specific by-product.

[0013] The present invention person As a result of further analyzing and examining the above-mentioned by-product, the present inventor identified that the by-product has the following general formula (1). In the following general formula (1), X represents a chlorine atom and / or a bromine atom.

[0014]

Chemical formula

[0015] As described above, by using a specific chemical reaction that has not been seen in the past as far as the present inventor knows, which uses 9-anthraldehyde as a raw material substance (also referred to as a starting material. Hereinafter, uniformly referred to as "raw material substance") and uses a specific aliphatic compound, it has become clear that anthracene-9-carboxylic acid can be obtained with high accuracy. In addition, in addition to the above facts, the present inventor focused on the specificity of a chemical composition (reaction mixture) containing a characteristic product generated by adopting the chemical reaction, and thus completed 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]

Chemical formula

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

[0019] Each of the above-described inventions is a chemical composition containing a compound represented by the above-described general formula (1). To the best of the inventor's knowledge, 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-described general formula (1) is produced, for example, as a by-product in the reaction mixture.

[0020] In particular, the fact that the content of the above-mentioned anthracene-9-carboxylic acid, as determined by HPLC (high-performance liquid chromatography), is 86% to 99% in area percentage, and that the content of the compound represented by the above-mentioned general formula (1), as determined by the same HPLC analysis, is 0.001% to 10% in area percentage, indicates that when anthracene-9-carboxylic acid is used as the main chemical composition (reaction mixture), high purity of anthracene-9-carboxylic acid in the chemical composition and / or high yield of anthracene-9-carboxylic acid in the manufacturing process are achieved.

[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 also referred to as "a predetermined aliphatic compound" for convenience), and an acidic compound in a nonpolar solvent or a mixed solvent of a polar solvent and water.

[0022] In this manufacturing method, a mixed solvent of a nonpolar solvent and water, or a mixed solvent of a polar solvent and water, is used, which is a mixture of at least the following (SL1), (SL2), and (SL3). As a result, this manufacturing 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 the prior art. (SL1) The aliphatic compound having a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds. (SL2) Oxidizing agent (SL3) Acidic compounds

[0023] The main reason why the above-mentioned higher reaction conversion rate to anthracene-9-carboxylic acid and / or higher yield of said anthracene-9-carboxylic acid can be achieved is the use of a specific aliphatic compound in the first reaction step. The inventors have found that the aliphatic compound, which has a boiling point of 120°C or higher and contains one or more carbon-carbon double bonds, can serve as a highly reliable scavenger for the by-products that may be generated in the first reaction step. In particular, it is noteworthy that the inventors have found that when the above-mentioned "oxidizing agent" is chlorite or chlorite salt, the aliphatic compound can play a role as a highly reliable scavenger for hypochlorous acid (HClO2) produced as a by-product. Experiments conducted by the inventors revealed that the scavenging rate of hypochlorous acid as a by-product was between 95% and 99.99%.

[0024] Furthermore, when the aforementioned "oxidizing agent" is chlorite or a chlorite salt, the fact that the compound represented by the following chemical formula (2) is produced in the first reaction step can be said to be one aspect that represents the characteristics of the method for producing the anthracene-9-carboxylic acid described above.

[0025] [ka]

[0026] Here, we show an example of the first reaction step. In the chemical equation (3) below, which is an example of the first reaction step, the example shown is when the "oxidizing agent" is chlorous acid. Specifically, it is thought that anthracene-9-carboxylic acid can be produced from the raw material 9-anthraldehyde through the following reaction steps (A) to (B) in chemical equation (3).

[0027] (A) Chlorite reacts with the raw material 9-anthraldehyde, and the chlorite ion attacks the aldehyde carbonyl (chemical reaction equation (3) (a) and (b)), thereby producing intermediate species A. (B) Subsequently, the hydrogen group in intermediate species A combines with the oxygen that is bonded with chlorine, and the hydrogen group is removed, forming a double bond between carbon and oxygen (chemical reaction equation (3)(c)), thereby producing anthracene-9-carboxylic acid (chemical substance B) and hypochlorous acid (chemical substance C).

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

[0029] [ka]

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

[0031] Specifically, it is thought that the generation of hypochlorous acid (chemical substance C), which may be produced in trace amounts as a by-product in the first reaction step, leads to the generation of trace amounts of chlorine molecules (Cl2) in an acidic solvent through the following hypothetical chemical reaction. [Chemical reaction equation] 2HOCl → H2O + O2 + Cl2

[0032] The inventors believe that at least a portion of the trace amounts of chlorine molecules (Cl2) generated react with the anthracene-9-carboxylic acid (chemical substance B) produced in the first reaction step, thereby generating a trace amount of the compound represented by chemical substance D. [Effects of the Invention]

[0033] One chemical composition of the present invention is, to the best of the inventor's knowledge, a unique chemical composition containing anthracene-9-carboxylic acid and a compound represented by the above-described 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 said anthracene-9-carboxylic acid compared to the prior art. [Brief explanation of the drawing]

[0034] [Figure 1A] (a) A diagram of the HPLC of the reaction mixture after the first reaction step in Example 1, and (b) A diagram of the HPLC of the purified solid substance after the third reaction step. [Figure 1B] This is a diagram of the HPLC results of the by-product isolated from the crude solid material after the third reaction step in Example 1. [Figure 2] The figures for Example 1 show (a) the proton nuclear magnetic resonance (1H-NMR) spectrum of the main product in the crude solid material after the first reaction step, and (b) the proton nuclear magnetic resonance (1H-NMR) spectrum of the by-product in the crude solid material after the first reaction step. [Figure 3] The figures for Example 1 show (a) the IR spectrum (infrared absorption spectrum) of the main product in the crude solid material after the first reaction step, and (b) the IR spectrum (infrared absorption spectrum) of the by-product in the crude solid material after the first reaction step. [Figure 4]This figure shows the C-13 nuclear magnetic resonance (13C-NMR) spectrum of the main product in the crude solid material after the first reaction step in Example 1. [Figure 5] This figure shows the C-13 nuclear magnetic resonance (13C-NMR) spectrum of the by-product in the crude solid material after the first reaction step in Example 1. [Figure 6] (a) A magnified view of a portion of Figure 4, and (b) A magnified view of a portion of Figure 5. [Modes for carrying out the invention]

[0035] <First Embodiment> The method for producing anthracene-9-carboxylic acid in this embodiment and the chemical composition containing anthracene-9-carboxylic acid will be described below.

[0036] <Manufacturing process for anthracene-9-carboxylic acid or its salts, and other chemical compositions> The anthracene-9-carboxylic acid and other chemical compositions of this embodiment can be produced based on the reaction mechanisms shown in the chemical reaction formula (Chemical Formula 1) and (A) to (B) already described, but a specific example of the process is as follows.

[0037] First, 9-anthraldehyde, the raw material for producing anthracene-9-carboxylic acid, can be obtained by known acquisition or production methods. For example, it can be obtained from commercially available sources, or relatively easily by using anthracene as a raw material and employing the Vilsmeier-Haack reaction, etc.

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

[0039] Specifically, the aliphatic compound that can be used 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 using this aliphatic compound, it is possible to reliably suppress the problems of generating a large amount of 9,10-anthraquinone, which is an undesirable by-product from the viewpoint of reliably obtaining the target substance anthracene-9-carboxylic acid, and / or leaving a large amount of unreacted 9-antraldehyde. As a result, it is possible to reliably increase the reaction conversion rate to anthracene-9-carboxylic acid and / or the yield of the anthracene-9-carboxylic acid.

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

[0041] A typical example of the 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. Of the above examples, (+)-limonene is a particularly preferred embodiment because, when the "oxidizing agent" described later is chlorous acid or a chlorite salt, it can play a role as a highly reliable scavenger of hypochlorous acid (HClO2) produced as a byproduct of the first reaction step.

[0042] The amount of the specified 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 per mole of 9-anthraldehyde, the raw material, is 0.5 moles to 10 moles. Within the above numerical range, using 0.5 moles (more preferably 1.2 moles) or more of the aliphatic compound is a preferred embodiment from the viewpoint of achieving higher accuracy and suppressing a reduction in the reaction rate of the first reaction step. On the other hand, within the above numerical range, using 10 moles (more preferably 2 moles) or less of the aliphatic compound is a preferred embodiment from the viewpoint of obtaining the target substance, anthracene-9-carboxylic acid, with high accuracy while suppressing the generation of undesirable by-products such as 9,10-anthraquinone, and / or reducing the processing burden after the first reaction step (in other words, from the viewpoint of reducing the economic burden).

[0043] Furthermore, typical examples of oxidizing agents in this embodiment include chlorous acid, bromous acid, chlorite, and / or bromous acid. Adopting chlorite and / or bromous acid, which have high chemical stability, is a preferred embodiment from the viewpoint of enhancing the safety and reliability of the production process. In addition, from the viewpoint of enhancing the safety and reliability of the production process through the first reaction step, it is a preferred embodiment to adopt alkali metal chlorite (typically sodium chlorite and / or potassium chlorite) or alkaline earth metal chlorite (typically calcium chlorite) among the chlorites. In particular, when preparing the aqueous solution of chlorite, adopting an aqueous solution of alkali metal chlorite or alkaline earth metal chlorite with 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] Furthermore, among the examples of oxidizing agents mentioned above, the amount of chlorite used (typically sodium chlorite, potassium chlorite, or calcium chlorite) is not particularly limited as long as the effects of this embodiment are not substantially impaired. The typical amount of chlorite used per mole of 9-anthraldehyde, the raw material, is 0.5 moles to 5 moles. Within the above numerical range, using 0.5 moles or more of chlorite is a preferred embodiment from the viewpoint of achieving higher accuracy and suppressing the reduction in the reaction rate of the first reaction step. On the other hand, within the above numerical range, using 5 moles or less of chlorite is a preferred embodiment from the viewpoint of obtaining the target substance, anthracene-9-carboxylic acid, with high accuracy while suppressing the generation of undesirable by-products such as 9,10-anthraquinone, and / or reducing the processing burden after the first reaction step (in other words, from the viewpoint of reducing the economic burden).

[0045] Furthermore, 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. Furthermore, 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. It is also possible to use a solvent prepared by mixing the above-mentioned polar solvent and nonpolar solvent with water.

[0046] Here, preferably, from the viewpoint of not easily inhibiting the first reaction step of this embodiment or promoting the first reaction step, it is preferable to use t-butanol from the examples of polar solvents described above. Also, from the same viewpoint as described above, it is preferable to use toluene or ethyl acetate from the examples of nonpolar solvents described above. In addition, although the mixing ratio of water is not particularly limited, from the viewpoint of reliably producing the final target substance, anthracene-9-carboxylic acid, in the first reaction step of this embodiment, it is preferable that the proportion of water be greater than 0 wt% and 80 wt% or less (more preferably 20 wt% to 50 wt%) of the total solvent.

[0047] The amount of the mixed solvent used in this embodiment is determined in such a way that the effects of this embodiment are not substantially impaired. the law of nature Preferably, the amount is 2 parts by mass or more per 1 part by mass of the raw material substance, 9-anthraldehyde. On the other hand, from the viewpoint of reducing the burden of post-treatment of the solvent used (in other words, from the viewpoint of reducing the economic burden), setting it to 50 parts by mass or less per 1 part by mass of the 9-anthraldehyde is a preferred embodiment.

[0048] Furthermore, in the first reaction step described above, an acidic compound is appropriately mixed in. This acidic compound is thought to play a role in activating the oxidizing agent in the first reaction step. Typical examples of acidic compounds in this embodiment include phosphoric acid, sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate, acetic acid, hydrochloric acid, or sulfuric acid.

[0049] Of the examples of acidic compounds mentioned 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 per mole of 9-anthraldehyde, the raw material, is 0.5 moles or more and 5 moles or less. Within the above numerical range, using 0.5 moles or more of dihydrogen phosphate is a preferred embodiment from the viewpoint of obtaining the target substance, anthracene-9-carboxylic acid, with higher accuracy and suppressing the generation of undesirable by-products such as 9,10-anthraquinone, and / or reducing the processing burden after the first reaction step (in other words, from the viewpoint of reducing the economic burden).

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

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

[0052] In the second reaction step of this embodiment, a sufficient amount of a reducing agent, such as sodium bisulfite, sodium sulfite, or sodium thiosulfate, is added to the acidic solution. After that, the solution is concentrated under reduced pressure, and the crude solid material is filtered off. Subsequently, in the third reaction step, a nonpolar solvent (e.g., toluene, xylene, ethyl acetate, butyl acetate, diethyl ether, 4-methyltetrahydropyran) and a basic aqueous solution (e.g., aqueous sodium bicarbonate solution, aqueous sodium carbonate solution, aqueous potassium carbonate solution, aqueous sodium hydroxide solution, aqueous potassium hydroxide solution) are added to the crude solid material. As a result, after extraction into the aqueous layer as a salt of anthracene-9-carboxylic acid, by liquid-liquid separation using an organic solvent (e.g., a nonpolar solvent such as toluene, xylene, ethyl acetate, butyl acetate, diethyl ether, 4-methyltetrahydropyran) is possible, allowing for the separation and removal of by-products such as 9,10-anthraquinone and the starting material 9-anthraldehyde. Subsequently, an acidic solution such as concentrated hydrochloric acid or concentrated sulfuric acid is added to the aqueous layer, and the resulting crystals obtained by acid precipitation are filtered off and recovered. The crystal is a chemical composition containing anthracene-9-carboxylic acid, which is the target substance of this embodiment. Therefore, it has become clear that by carrying out the first reaction step, it is possible to ensure that the reaction mixture described above in this embodiment contains at least the anthracene-9-carboxylic acid or a salt thereof.

[0053] In one of the methods for producing anthracene-9-carboxylic acid according to this embodiment, which uses 9-anthraldehyde as a raw material, a characteristic feature of this method is that by employing the first reaction step described above, the reaction mixture may contain a compound represented by the following general formula (1). In the following general formula (1), X represents a chlorine atom and / or a bromine atom.

[0054] [ka]

[0055] Furthermore, one of the advantages of the manufacturing method of this embodiment is that it employs only reaction processes that are friendly to humans and the environment, 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 described above is less than 0.01% by mass. It is also worth noting that the content of the aforementioned heavy metals or transition metals that may be contained in the reaction mixture obtained after the second and third reaction steps described above is also less than 0.01% by mass, not just in the first reaction step described above.

[0056] <Examples> The embodiments described above will be explained in detail through the following examples, but the scope of the present invention and its embodiments is not limited by the description of these examples. Examples 1 to 4, described later, all involve processing based on the first to third reaction steps of the embodiments described above. Comparative Examples 1 to 4, described later, employ a method for producing anthracene-9-carboxylic acid using the conventional Pinick oxidation reaction.

[0057] (Example 1) In a reaction vessel equipped with a stirrer and having an internal volume of 100 mL (milliliters), a mixed solvent consisting of 10 mL of t-butanol and 5 mL of pure water at 20°C, 1.03 g (0.005 mol) of 9-antraldehyde, the starting material, 0.82 g (0.006 mol) of (+)-limonene, an example of a predetermined aliphatic compound in the first embodiment, 1.96 g (0.0055 mol) of a 25 wt% aqueous sodium chlorite solution, an example of an oxidizing agent in the first embodiment, and 0.936 g (0.006 mol) of sodium dihydrogen phosphate dihydrate, an example of an acidic compound in the first embodiment, were mixed with stirring for about 1 hour. This corresponds to the first reaction step in 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 starting material 9-anthraldehyde, the target substance anthracene-9-carboxylic acid, the by-product 9,10-anthraquinone, and other products in the reaction mixture were investigated. 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. Also, "QN" in Table 1 means 9,10-anthraquinone.

[0059] In this embodiment, sodium bisulfite, an example of a reducing agent in the first embodiment, and water are added to the liquid reaction mixture after the first reaction step. Then, t-butanol is removed by distillation under reduced pressure concentration. After that, the crude solid substance is obtained by filtering off the residue. This corresponds to the second reaction step in the first embodiment.

[0060] Furthermore, in this embodiment, the crude solid material obtained in the second reaction step was washed with ethyl acetate and a 10 wt% aqueous sodium bicarbonate solution. Then, concentrated hydrochloric acid was added to the washed aqueous layer, acid precipitation occurred, and the mixture was filtered to obtain 1.02 g of purified solid material (chemical composition). This corresponds to the third reaction step in the first embodiment. The final obtained chemical composition was analyzed using HPLC, and its purity was determined by 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 its yield was 91.8 mol%, which are extremely excellent values.

[0061] [Regarding the results of various analyses] Here, we will describe the results of various analyses concerning the chemical composition containing anthracene-9-carboxylic acid obtained in this example, which is of high yield and high purity.

[0062] Interestingly, when the chemical composition of this embodiment was analyzed using various measurement methods, it became clear that by adopting the first reaction step in this embodiment, a chemical composition was obtained in which the reaction mixture contained a compound represented by the following chemical formula (2), which, to the best of the inventor's knowledge, has not been observed in conventional by-products. [ka]

[0063] Therefore, regarding the various analytical results, we will explain in particular the process by which the aforementioned unique compound obtained by employing the first reaction step was identified.

[0064] Figure 1A shows (a) the HPLC (High Performance Liquid Chromatography) of the reaction mixture after the first reaction step and (b) the HPLC of the purified solid material after the third reaction step in this embodiment. Figure 1B shows the HPLC of the by-product isolated from the purified solid material after the third reaction step in this embodiment. Figure 2 shows (a) the proton nuclear magnetic resonance (ITEM) of the main product in the purified solid material after the third reaction step in this embodiment. 1 (b) A diagram of the 1H-NMR spectrum and (b) the proton nuclear magnetic resonance of the by-product in the purified solid material after the third reaction step. 1 Figure 3 shows the (a) IR spectrum (infrared absorption spectrum) of the main product in the purified solid material after the third reaction step and (b) the IR spectrum (infrared absorption spectrum) of the by-product in the purified solid material after the third reaction step in this embodiment. In Figure 3, characteristic absorption peaks are shown in square frames for clarity. Figure 4 shows the C-13 nuclear magnetic resonance (C-13) spectrum of the main product in the purified solid material after the third reaction step in this embodiment. 13 Figure 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 embodiment. 13This is a diagram of the 1C-NMR spectrum. Figure 6 is a magnified view of part of Figure 4 (a) and a magnified view of part of Figure 5 (b). In Figure 1A, "9-AC" means anthracene-9-carboxylic acid, and "9-AA" means 9-antraldehyde. Also, "QN" in Figure 1A means 9,10-anthraquinone.

[0065] First, as shown in Figure 1A(a), HPLC (High-Performance Liquid Chromatography) analysis revealed that even in the crude solid material obtained after the first reaction step, the target substance, anthracene-9-carboxylic acid, was produced with the formation of by-products sufficiently suppressed. Regarding the identification of the substance showing the strongest peak in Figure 1A(a), in addition to the HPLC analysis, the inventors confirmed that the analysis results of the main product of the crude solid material were consistent with the analysis results of the reference substance by comparing it with anthracene-9-carboxylic acid, a reference substance whose substance had already been identified, based on various analytical results described later. Similarly, "9-AA" and "QN" shown in Figure 1A(a) were also identified by comparing them with their respective identified reference substances.

[0066] Furthermore, as shown in Figure 1A(b), this analysis revealed that the purified solid substance after the third reaction step (the chemical composition of this example) contains almost no by-products other than "9-AC," meaning that a very high-purity anthracene-9-carboxylic acid is produced.

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

[0068] Here, the inventors conducted further analysis and investigations to identify the isolated substance ("x" in Figure 1B), and a very interesting finding emerged. Specifically, the proton nuclear magnetic resonance (C / F) of the reference substance (i.e., the compound represented by the above chemical formula (2)) obtained by chlorinating the 10-position of the anthracene skeleton in anthracene-9-carboxylic acid using N-chlorosuccinimide (NSC) ( 1 The inventors compared the 1H-NMR spectrum with the spectrum shown in Figure 2(b) for the isolated substance (labeled "x" in Figure 1B) and confirmed that they matched. Therefore, the inventors determined that the isolated substance is very likely to be the compound (9-AC-Cl) represented by the above-mentioned chemical formula (2).

[0069] Furthermore, the inventors performed IR spectral analysis and C-13 nuclear magnetic resonance analysis on anthracene-9-carboxylic acid (9-AC), the target substance of this embodiment, as shown in Figures 2(a), 3(a), 4, and 6(a). In addition, they performed IR spectral analysis and C-13 nuclear magnetic resonance analysis on the compound (9-AC-Cl) represented by the above-mentioned chemical formula (2), as shown in Figure 2(b), as well as in Figures 3(b), 5, and 6(b).

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

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

[0072] (Examples 2-4) In Examples 2 to 4, the 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 were used as the "specified aliphatic compound" instead of (+)-limonene, which was used as the "specified aliphatic compound" in Example 1. As a result, the reaction conversion rates from the starting material 9-anthraldehyde to the reaction mixture were investigated for the starting material 9-anthraldehyde, the target substance anthracene-9-carboxylic acid, the by-product 9,10-anthraquinone, and other products. Table 1 below shows these results along with the results for Example 1.

[0073] [Table 1]

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

[0075] (Comparative Examples 1-5) The inventors conducted comparative experiments using the following scavengers or additives instead of the "specified aliphatic compound" in order to compare with the above-described examples. The specific conditions for Comparative Examples 1 to 5 are as follows.

[0076] In Comparative Examples 1 to 5, the reaction step corresponding to the first reaction step was carried out under the same conditions as in Example 1, except that the "specified aliphatic compound" was absent, or that amylene, sulfamic acid, hydrogen peroxide, or resorcinol were used as a scavenger or additive in place of the "specified aliphatic compound." As a result, the reaction conversion rates from the starting material 9-anthraldehyde to the starting material 9-anthraldehyde in the reaction mixture were investigated.

[0077] [Table 2]

[0078] As a result, when comparing the examples using "specified aliphatic compounds," as in Examples 1 to 4, with Comparative Examples 1 to 5, it became clear that, with the exception of amylene, the reaction conversion rate from the starting material 9-anthraldehyde to the target substance anthracene-9-carboxylic acid was significantly lower in each comparative example. 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 reaction conversion rate among Examples 1 to 4.

[0079] In addition to the above-described Examples 1 to 4, several other experiments have shown that by employing the above-described embodiments, it is possible to produce anthracene-9-carboxylic acid (9-AC) with very high yield and / or very high reaction conversion rate.

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

[0081] Furthermore, based on Examples 1 to 4 and several other experiments, the high reaction conversion rate is noteworthy, as the HPLC analysis shows that the content (residual amount) of unreacted (in other words, remaining in the reaction vessel) raw material, 9-anthraldehyde, is 5 area percent or less (more narrowly, 3 area percent or less, and even more narrowly, 2 area percent or less).

[0082] Furthermore, as demonstrated in Examples 1 to 4 and several other experiments, the high reaction conversion rate is noteworthy, as the HPLC analysis shows that the content of the undesirable by-product 9,10-anthraquinone is 5 area% or less (more narrowly, 3 area% or less) by area percentage. In particular, when (+)-limonene is used as the aliphatic compound (specified aliphatic compound) with a boiling point of 120°C or higher and containing one or more carbon-carbon double bonds, it was found that the content of the undesirable by-product 9,10-anthraquinone is extremely low, at 1.55 area% or less by area percentage.

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

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

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

[0086] The method for producing anthracene-9-carboxylic acid or its salts, and the chemical compositions of the present invention, can be widely used as useful chemical substances or for producing the same, for materials with diverse applications (for example, functional materials or intermediates used in various electrical products).

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 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 or a salt thereof according to claim 7.

9. 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.

10. 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.

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