Production method of aromatic compound, and production method of terephthalic acid

Abstract

To provide an efficient production method of an aromatic compound in excellent atom economy by subjecting a biomass-derived furan compound with an easily procurable specific structure to a DA reaction with ethylene without hydrogen reduction, and a production method of terephthalic acid.SOLUTION: A production method of terephthalic acid comprises following steps (A) and (B). Step (A): a step of making a furan compound represented by a specific general formula (I) react with ethylene to obtain an aromatic compound represented by a specific general formula (II) and / or a specific general formula (III). Step (B): a step of oxidizing the aromatic compound represented by the specific general formula (II) and / or the specific general formula (III) obtained in the step (A).SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing an aromatic compound and a method for producing terephthalic acid. [Background technology]

[0002] In order to solve the global warming caused by the increase in greenhouse gases such as carbon dioxide and the associated climate change issues, efforts to achieve carbon neutrality towards a decarbonized society are accelerating. For this reason, it is extremely important to produce bulk chemicals that were originally derived from petroleum in a sustainable manner from biomass, and vigorous research and development is being carried out worldwide.

[0003] Terephthalic acid is a raw material for polyester, which is used to make synthetic fibers, films, plastic bottles, etc., and due to its wide range of uses, there is a very high demand for biomass-derived products.

[0004] In recent years, methods for producing terephthalic acid using paraxylene produced from biomass as a synthetic starting material have been investigated. A typical proposed route involves producing paraxylene by the Diels-Alder reaction (hereinafter abbreviated as DA reaction) of ethylene with 2,5-dimethylfuran, which is synthesized by dehydrating and hydrogenating sugars derived from biomass resources, and then producing terephthalic acid through a subsequent oxidation step (see, for example, Patent Document 1).

[0005] In addition, a route has also been investigated in which 5-hydroxymethylfurfural, which is also produced from sugars, is oxidized to convert it into a 5-hydroxymethylfurancarboxylic acid derivative, which is then subjected to a DA reaction with ethylene to produce a 4-hydroxymethylbenzoic acid derivative, which is then subjected to a subsequent oxidation step to produce terephthalic acid (see, for example, Non-Patent Document 1). This document also reports that the DA reaction between 5-hydroxymethylfurfural and ethylene does not proceed.

[0006] On the other hand, Non-Patent Document 2 proposes a technique for improving the thermal stability and reaction stability by acetal-protecting 5-hydroxymethylfurfural obtained from sugars. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] International Publication No. 2009 / 110402 [Non-patent literature]

[0008] [Non-Patent Document 1] Davis, MEet al. Proc. Natl. Acad. Sci. 2014, 111, 8363 [Non-patent document 2] Nakajima, K. et al. Angew. Chem. Int. Ed. 2018, Vol. 57, p. 8235 Summary of the Invention [Problem to be solved by the invention]

[0009] Although the production methods disclosed in Patent Document 1 all use 2,5-dimethylfuran as a starting material, the entire process of producing terephthalic acid from biomass includes both a hydrogen reduction reaction and an oxidation reaction, and from the perspective of atom economy, it is desirable to eliminate the hydrogen reduction step.In the production method disclosed in Non-Patent Document 1, the oxidation step is divided into two stages instead of eliminating the hydrogen reduction step, and there is room for improvement in efficiency.

[0010] The present invention aims to provide a method for producing aromatic compounds and terephthalic acid, which is efficient and has excellent atom economy, by subjecting a furan compound having a specific structure that is procurable from biomass to a DA reaction with ethylene without hydrogen reduction. [Means for solving the problem]

[0011] In order to solve the above problems, the present invention employs any of the following means.

[0012] That is, the method for producing an aromatic compound according to the present invention is characterized by comprising the step of [1] reacting a furan compound represented by general formula (I) with ethylene to obtain an aromatic compound represented by general formula (II) and / or general formula (III).

[0013] [ka] [In general formula (I), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 R are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0014] [ka] [In general formula (II), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 R are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0015] [ka] [In general formula (III), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0016] The method for producing terephthalic acid according to the present invention is characterized by including the step [2] of oxidizing an aromatic compound represented by general formula (II) and / or general formula (III).

[0017] [ka] [In general formula (II), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 R are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0018] [ka] [In general formula (III), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0019] The method for producing terephthalic acid according to the present invention is characterized by including the following steps (A) and (B): [3] Step (A): A step of reacting a furan compound represented by general formula (I) with ethylene to obtain an aromatic compound represented by general formula (II) and / or general formula (III). Step (B): A step of oxidizing the aromatic compound represented by general formula (II) and / or general formula (III) obtained in step (A).

[0020] [ka] [In general formula (I), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 R are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0021] [ka] [In general formula (II), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 R are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.]

[0022] [ka] [In general formula (III), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.] [Effects of the Invention]

[0023] The present invention provides a method for producing aromatic compounds and terephthalic acid efficiently and with excellent atom economy. DETAILED DESCRIPTION OF THE INVENTION

[0024] Preferred embodiments of the present invention will be described in detail below. It should be understood that the present invention is not limited to the embodiments described below, but also includes various modifications that are implemented within the scope of the present invention.

[0025] (1) Raw material compound (1-1) Production of aromatic compounds In the method for producing an aromatic compound of the present invention, the raw material compounds are a furan compound represented by the following general formula (I) (hereinafter, sometimes simply referred to as a furan compound) and ethylene.

[0026] [ka]

[0027] In general formula (I), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3R are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 R is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. In this specification, for example, an alkyl group having 1 to 5 carbon atoms means an alkyl group having 1 to 5 carbon atoms. The same applies to other substituents that specify the number of carbon atoms.

[0028] R in general formula (I) 1 is -CH2OH, methyl group, -CH2OC(O)R 4 , -C(O)OR 5 is preferred. 2 and R 3 is preferably a methyl group, an ethyl group, an ethylene group, a trimethylene group, or a dimethyltrimethylene group. 4 is preferably a methyl group or a phenyl group. 5 is preferably a hydrogen atom or a methyl group. 1 ~R 5 Specific examples of furan compounds having a group having the formula (I-1) to (I-30) below are given as examples of furan compounds having a group having the formula (I-1) to (I-30) below. In terms of reducing the number of reaction steps when synthesizing from a sugar, R 1 More preferably, R is —CHOH. 1 Specific examples of furan compounds in which R is a group represented by -CHOH include dimethyl acetal, diethyl acetal, ethylene acetal, trimethylene acetal, and dimethyl trimethylene acetal of 5-hydroxymethylfurfural, which are represented by the following formulas (I-1) to (I-5). 2 and R 3 More preferably, R is a trimethylene group. 1 is a group represented by -CHOH, and R 2 and R 3 The furan compound in which is a trimethylene group is a trimethylene acetal of 5-hydroxymethylfurfural represented by the following formula (I-4).

[0029] [ka]

[0030] Each raw material compound may be a commercially available product, a product synthesized by a known technique, or a product synthesized by a new method. Specifically, for example, the furan compounds represented by the above formulas (I-1) to (I-5) can be synthesized by the method described in Experimental Example 7 of Japanese Patent No. 6900801. Furthermore, for each raw material compound, either a product derived from a petroleum-based raw material or a product derived from biomass can be used.

[0031] In particular, in the aromatic compound production method of the present invention, it is preferable that the furan compound is derived from biomass. Also, in the aromatic compound production method of the present invention, it is preferable that the ethylene is derived from biomass. When one or more of these raw material compounds are derived from biomass, the resulting aromatic compound and terephthalic acid can be treated as at least partially biomass-derived products. In particular, when all raw material compounds are derived from biomass, the resulting aromatic compound and terephthalic acid can also be treated as completely biomass-derived products, which is most preferable. Also, it is preferable that the raw material compounds, furan compound and ethylene, are recovered as unreacted fractions from the reaction products in the aromatic compound production method of the present invention, separated and purified as necessary, and reused.

[0032] (1-2) Production of terephthalic acid In a first embodiment of the method for producing terephthalic acid of the present invention, the raw material compound is an aromatic compound represented by the following general formula (II) and / or general formula (III) (hereinafter, sometimes simply referred to as an aromatic compound). That is, the raw material compound is at least one of the aromatic compound represented by the general formula (II) and the aromatic compound represented by the general formula (III).

[0033] [ka]

[0034] In general formula (II), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 R are alkyl groups having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0035] [ka]

[0036] In general formula (III), R 1 -CH2OH, alkyl group with 1 to 5 carbon atoms, -CH2OC(O)R 4 , -C(O)OR 5 R is any one of the groups represented by 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

[0037] R in general formula (II) 1 ~R 5 The preferred embodiments of R in general formula (III) are the same as those in general formula (I). 1 , R 4 , R 5 The preferred embodiments etc. of are the same as those of the above general formula (I).

[0038] The aromatic compound may be a commercially available product, a product synthesized by a known technique, or a product synthesized by a new method, or an aromatic compound produced by the method for producing an aromatic compound of the present invention may be used.

[0039] Furthermore, although both petroleum-based and biomass-derived aromatic compounds can be used, those derived from biomass are preferred. When the aromatic compound is derived from biomass, the resulting terephthalic acid can be treated as a biomass-derived product. It is also preferred that the aromatic compound is recovered as an unreacted component from the reaction product in the first embodiment of the method for producing terephthalic acid of the present invention, separated and purified as necessary, and reused.

[0040] (2) Reaction conditions (2-1) Method for producing aromatic compounds The method for producing an aromatic compound of the present invention includes a step of reacting a furan compound represented by the above general formula (I) with ethylene to obtain an aromatic compound represented by general formula (II) and / or general formula (III). The reaction that preferably proceeds in this step is as shown in the following formula (1). When the DA reaction between the furan compound and ethylene proceeds, a bicyclo intermediate is produced. Further, a dehydration reaction of the bicyclo intermediate proceeds, thereby obtaining an aromatic compound. R in the aromatic compound obtained here 1 ~R 5 The preferred embodiments etc. of are the same as those of the above general formula (I).

[0041] [ka]

[0042] In addition to the reaction of formula (1), an aromatic compound having an aldehyde group may be produced by hydrolysis of the acetal structure as shown in the following general formula (2), and this may form a mixture with an aromatic compound having an acetal structure.

[0043] [ka]

[0044] In the method for producing an aromatic compound of the present invention, a catalyst may be used in the DA reaction. The catalyst is not particularly limited as long as it promotes the DA reaction of a furan compound with ethylene, and examples thereof include heterogeneous catalysts and homogeneous catalysts.

[0045] Examples of heterogeneous catalysts include zeolites, metal oxides, clays, acidic ion exchange resins, heteropolyacids, solid phosphoric acid, and solid acids such as hydroxyapatite. Zeolites or metal oxides are preferred as heterogeneous catalysts due to their high catalytic activity for the DA reaction. Examples of zeolites include MFI, X, Y, beta, and mordenite. Examples of metal oxides include oxides containing one or more metal elements selected from the group consisting of scandium, yttrium, cerium, titanium, zirconium, vanadium, niobium, tantalum, chromium, molybdenum, tungsten, manganese, iron, zinc, cadmium, aluminum, gallium, indium, silicon, germanium, tin, and lead. More specifically, examples include scandium oxide (Sc2O3), cerium oxide (CeO2), anatase-type titanium oxide (A-TiO2), rutile-type titanium oxide (R-TiO2), zirconium oxide (ZrO2), vanadium oxide (VO5), niobium oxide (Nb2O5), tantalum oxide (Ta2O5), chromium oxide (Cr2O3), molybdenum oxide (MoO3), tungsten oxide (WO3), manganese oxide (MnO2), iron oxide (Fe2O3, Fe3O4), zinc oxide (ZnO), aluminum oxide (Al2O3), gallium oxide (Ga2O3), indium oxide (In2O3), silicon dioxide (SiO2), germanium oxide (GeO2), tin oxide (SnO2), and lead oxide (PbO). Examples of clay include kaolin, montmorillonite, bentonite, saponite, and acid clay. Examples of acidic ion exchange resins include styrene-based sulfonic acid-type ion exchange resins and phenol-based sulfonic acid-type ion exchange resins. More specifically, examples include DIAION manufactured by Mitsubishi Chemical Corporation, Lewatit manufactured by Lanxess, Amberlite and Amberlyst manufactured by Rohm and Haas, and DOWEX manufactured by Dow. Examples of heteropolyacids include phosphotungstic acid, silicotungstic acid, phosphomolybdic acid, and silicomolybdic acid, which can be supported in any ratio on a carrier such as silica gel. Examples of solid phosphoric acid include phosphates containing one or more metal elements selected from the group consisting of silicon, boron, aluminum, zirconium, zinc, titanium, and iron.More specific examples include silicon phosphate, boron phosphate, aluminum phosphate, zirconium phosphate, zinc phosphate, titanium phosphate, and iron phosphate.

[0046] Examples of the homogeneous catalyst include metal Lewis acids. Examples of the metal Lewis acids include yttrium chloride, yttrium trifluoromethanesulfonate, gadolinium chloride, gadolinium trifluoromethanesulfonate, titanium chloride, titanium bromide, titanium trifluoromethanesulfonate, iron chloride, iron bromide, iron trifluoromethanesulfonate, cobalt chloride, cobalt trifluoromethanesulfonate, nickel chloride, nickel trifluoromethanesulfonate, copper chloride, copper trifluoromethanesulfonate, zinc chloride, zinc trifluoromethanesulfonate, aluminum chloride, indium chloride, and indium trifluoromethanesulfonate.

[0047] The catalyst may be a mixture of any two or more of the above catalysts, or a composite of two or more catalysts chemically combined for use. For example, silicon dioxide carrying a metal halide, and silica-alumina (SiO2-Al2O3), a composite of silicon dioxide and aluminum oxide, are also included in the catalysts that can be used in the present invention.

[0048] In the method for producing an aromatic compound of the present invention, a solvent may be used in the DA reaction. Specifically, at least one solvent selected from the group consisting of hydrocarbons, alcohols, ethers, ketones, and esters can be used. Examples of hydrocarbons include saturated aliphatic hydrocarbons such as pentane, neopentane, hexane, cyclohexane, heptane, methylcyclohexane, octane, isooctane, nonane, decane, decalin, dodecane, and isododecane, and aromatic hydrocarbons such as benzene, toluene, xylene, trimethylbenzene, tetrahydronaphthalene, and methylnaphthalene. Examples of alcohols include monoalcohols such as methanol, ethanol, propanol, isopropyl alcohol, butanol, isobutyl alcohol, t-butyl alcohol, pentanol, hexanol, heptanol, octanol, nonanol, and decanol, and diols such as ethylene glycol, propanediol, butanediol, pentanediol, and neopentyl glycol. Examples of ethers include diethyl ether, tetrahydrofuran, dimethoxyethane, methyl t-butyl ether, tetrahydropyran, dipropyl ether, diisopropyl ether, methyltetrahydropyran, cyclopentyl methyl ether, etc. Examples of ketones include acetone, butanone, pentanone, cyclopentanone, hexanone, cyclohexanone, isophorone, etc. Examples of esters include methyl acetate, ethyl acetate, methyl propionate, propyl acetate, ethyl propionate, methyl butanoate, butyl acetate, etc.

[0049] In the method for producing an aromatic compound of the present invention, a base may be used as an additive in the DA reaction. The presence of a base in the reaction system improves the stability of the cyclic acetal, suppressing side reactions such as polymerization and ring-opening reactions of the reaction intermediate, and tends to improve the yield of the target aromatic compound. Specific examples of the base include inorganic bases such as sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, and potassium bicarbonate, and organic bases such as triethylamine.

[0050] The reaction conditions such as the amount of feed to the reactor and the reaction temperature are appropriately adjusted depending on the presence or absence of a catalyst, and if a catalyst is used, the type and amount of the catalyst.

[0051] In the method for producing an aromatic compound of the present invention, the DA reaction can be carried out by a known reaction method such as a batch method or a continuous method.

[0052] In the method for producing an aromatic compound of the present invention, the reaction temperature is not particularly limited, but is preferably 50°C or higher, more preferably 100°C or higher, and even more preferably 200°C or higher. The reaction temperature is preferably 600°C or lower, more preferably 500°C or lower, and even more preferably 400°C or lower. The higher the reaction temperature, the more likely the raw material consumption per the same amount of catalyst is to be accelerated. On the other hand, if the reaction temperature is too high, the selectivity of the product tends to decrease.

[0053] In the method for producing an aromatic compound of the present invention, the ethylene pressure in the reactor is not limited, but the ethylene pressure in the reactor is preferably 0.1 MPa or more, more preferably 0.5 MPa or more, in terms of gauge pressure. The ethylene pressure in the reactor is preferably 20 MPa or less, more preferably 10 MPa or less. The higher the ethylene pressure in the reactor, the higher the probability of contact between the raw material furan compound and ethylene, resulting in a faster reaction rate. On the other hand, performing the reaction at a high ethylene pressure requires reaction equipment with high pressure resistance, and the selectivity of the product tends to decrease.

[0054] In the method for producing an aromatic compound of the present invention, there is no limitation on the amount of furan compound used relative to the reaction solvent, but the concentration of the raw material relative to the reaction solvent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. If the raw material concentration is too low, a large amount of solvent will be used, which will require a reaction vessel that is too large, and this will tend to reduce production efficiency.

[0055] (2-2) Method for producing terephthalic acid A first embodiment of the method for producing terephthalic acid of the present invention includes a step of oxidizing an aromatic compound represented by the above general formula (II) and / or general formula (III). The reaction that preferably proceeds in this step is as shown in the following formula (3), and the target compound, terephthalic acid, is obtained by the oxidation reaction. When the aromatic compound represented by general formula (II) is used as a raw material, alcohol and / or diol derived from the raw material are by-produced.

[0056] [ka]

[0057] In the first embodiment of the method for producing terephthalic acid of the present invention, a catalyst may be used in the oxidation reaction. The catalyst is not limited as long as it is a metal or metal compound having oxidizing ability. Specific examples include typical metals of Groups 1 and 2 of the periodic table and their compounds, transition metals of Groups 3 to 11 of the periodic table and their compounds, typical metals of Groups 12 to 14 of the periodic table and their compounds, and mixtures (including alloys) of these. Examples of typical metals of Groups 1 and 2 of the periodic table and their compounds include cesium, magnesium, calcium, and their compounds. Examples of transition metals of Groups 3 to 11 of the periodic table and their compounds include scandium, zirconium, niobium, tantalum, chromium, molybdenum, manganese, rhenium, iron, ruthenium, cobalt, nickel, palladium, platinum, copper, silver, gold, and their compounds. Examples of typical metals of Groups 12 to 14 of the periodic table and their compounds include zinc, indium, tin, lead, and their compounds. Among these, magnesium, manganese, rhenium, cobalt, palladium, platinum, copper, silver, gold, zinc, and compounds thereof are preferred because of their high oxidation catalytic activity.

[0058] In the first embodiment of the method for producing terephthalic acid of the present invention, a solvent may be used in the oxidation reaction. The reaction solvent is not particularly limited as long as it dissolves the aromatic compound as the raw material.

[0059] In the first embodiment of the method for producing terephthalic acid of the present invention, a base may be used as an additive in the oxidation reaction. The presence of a base in the reaction system improves the stability of the cyclic acetal, making it possible to suppress side reactions such as polymerization and ring-opening reactions of the reaction intermediate, and also tends to improve the yield of the target aromatic compound. Specific examples of the base include inorganic bases such as sodium hydroxide, sodium carbonate, sodium bicarbonate, potassium hydroxide, potassium carbonate, and potassium bicarbonate, and organic bases such as triethylamine.

[0060] In the first embodiment of the method for producing terephthalic acid of the present invention, the oxygen source used in the oxidation reaction is not particularly limited, but it is preferable to use oxygen gas or an oxygen-containing gas such as air, since separation and purification are not required after completion of the reaction.

[0061] The reaction conditions such as the amount of feed to the reactor and the reaction temperature are appropriately adjusted depending on the presence or absence of a catalyst, and if a catalyst is used, the type and amount of the catalyst.

[0062] In the first embodiment of the method for producing terephthalic acid of the present invention, the oxidation reaction can be carried out by a known reaction method such as a batch method or a continuous method.

[0063] In the first embodiment of the method for producing terephthalic acid of the present invention, the reaction temperature is not particularly limited, but is preferably 30°C or higher, more preferably 40°C or higher, and even more preferably 60°C or higher. The reaction temperature is preferably 300°C or lower, more preferably 250°C or lower, and even more preferably 200°C or lower. The higher the reaction temperature, the more likely the raw material consumption per the same amount of catalyst is to be accelerated. On the other hand, if the reaction temperature is too high, the reaction tends to become too vigorous and difficult to control.

[0064] In the first embodiment of the method for producing terephthalic acid of the present invention, there is no limitation on the pressure when gaseous oxygen or an oxygen-containing gas is supplied into the reactor, but the pressure in the reactor is preferably 0.1 MPa or more, more preferably 0.5 MPa or more, in terms of gauge pressure. The pressure in the reactor is preferably 20 MPa or less, more preferably 10 MPa or less. The higher the oxygen pressure in the reactor, the faster the reaction rate. On the other hand, in order to carry out the reaction at a high oxygen pressure, expensive reaction equipment with high pressure resistance is required.

[0065] In the first embodiment of the method for producing terephthalic acid of the present invention, the amount of the aromatic compound used as the raw material relative to the reaction solvent is not limited, but the concentration of the raw material relative to the reaction solvent is preferably 0.1% by mass or more, more preferably 0.5% by mass or more, and even more preferably 1% by mass or more. If the raw material concentration is too low, a large amount of solvent is used, which requires a reaction vessel that is too large, and this tends to reduce production efficiency.

[0066] A second embodiment of the method for producing terephthalic acid of the present invention includes the following steps (A) and (B). Step (A): A step of reacting a furan compound represented by the general formula (I) with ethylene to obtain an aromatic compound represented by the general formula (II) and / or the general formula (III). Step (B): A step of oxidizing the aromatic compound represented by the general formula (II) and / or the general formula (III) obtained in the step (A).

[0067] The preferred embodiments of step (A) are the same as those of the method for producing an aromatic compound of the present invention described above, and the preferred embodiments of step (B) are the same as those of the first embodiment of the method for producing terephthalic acid of the present invention described above.

[0068] (3) Separation and purification (3-1) Production of aromatic compounds The method for producing an aromatic compound of the present invention may further include a step of separating and purifying the aromatic compound represented by general formula (II) and / or general formula (III). The reaction product containing the aromatic compound can be separated and purified by known methods depending on the content of the aromatic compound and the type of impurities. This separation and purification method is not particularly limited, and examples thereof include chromatographic techniques such as those described in a known literature (J. Am. Chem. Soc. 2021, 143, 16865).

[0069] In the method for producing an aromatic compound of the present invention, when the reaction product contains unreacted raw material compounds, such as a furan compound or ethylene, it is preferable to separate and recover the aromatic compound and the raw material compounds, and further purify them as necessary, and reuse them as raw material compounds for the aromatic compound, as described above. Furthermore, when an alcohol or diol is contained in the reaction product as a result of hydrolysis of the raw material compound or the product acetal compound, it is preferable to separate and recover them, and further purify them as necessary, and reuse them in the synthesis of the raw material compound, the furan compound.

[0070] (3-2) Production of terephthalic acid The method for producing terephthalic acid of the present invention may further include a step of separating and purifying terephthalic acid. The reaction product containing terephthalic acid can be separated and purified by known methods depending on the content of terephthalic acid and the types of impurities.

[0071] In the method for producing terephthalic acid of the present invention, when the reaction product contains an unreacted aromatic compound as a raw material compound, it is preferable to separate and recover terephthalic acid and the raw material aromatic compound as described above, and further purify them as necessary to reuse them as raw material compounds for terephthalic acid. Also, when the reaction product contains an alcohol or diol as a by-product of the oxidation reaction or due to hydrolysis of the raw material compound, it is preferable to separate and recover them, and further purify them as necessary to reuse them in the synthesis of a furan compound as a raw material in the method for producing an aromatic compound of the present invention. [Example]

[0072] The present invention will be described in more detail below with reference to examples, but the present invention is not limited thereto.

[0073] [Example 1] 0.05 g of the furan compound represented by formula (I-4) above, prepared by the method described in a publicly known literature (ChemCatChem. 2022, 14, e202200191.), and 0.5 g of triethylamine were dissolved in 4.95 g of hexane, and the DA reaction was carried out in the presence of 0.013 g of proton-type Y-type zeolite CBV760 (manufactured by Zeolyst) in an autoclave with ethylene gas injected at 2 MPa at 300°C for 3 hours. The reaction solution was then cooled to room temperature, concentrated using an evaporator, and analyzed by NMR to confirm the production of the target aromatic compound.

[0074] [Example 2] 0.25 g of the furan compound represented by formula (I-4) above, prepared by the method described in a published literature (ChemCatChem. 2022, 14, e202200191.), and 9.6 mg of iron trifluoromethanesulfonate were dissolved in 5 g of dioxane, and the DA reaction was carried out in an autoclave at 270°C for 3 hours with ethylene gas injected at 5 MPa. The reaction solution was then cooled to room temperature, concentrated using an evaporator, and analyzed by NMR. The aromatic compound represented by formula (II-4) below was obtained in a yield of 0.7%.

[0075] [ka] [Industrial Applicability]

[0076] According to the present invention, aromatic compounds useful as polymer raw materials can be efficiently obtained. Furthermore, when a biomass-derived furan compound and biomass-derived ethylene are used, an aromatic compound derived entirely from biomass can be obtained. By using such an aromatic compound derived entirely from biomass in combination with a biomass-derived glycol, a polyester derived entirely from biomass can be obtained.

Claims

1. A method for producing an aromatic compound, comprising the step of reacting a furan compound represented by general formula (I) with ethylene to obtain an aromatic compound represented by general formula (II) and / or general formula (III). 【Chemistry 1】 [In general formula (I), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 【Chemistry 2】 [In general formula (II), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 【Transformation 3】 [In general formula (III), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

2. A method for producing terephthalic acid, comprising a step of oxidizing an aromatic compound represented by general formula (II) and / or general formula (III). 【Chemistry 4】 [In general formula (II), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 【Transformation 5】 [In general formula (III), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

3. A method for producing terephthalic acid, comprising the following steps (A) and (B): Step (A): A step of reacting a furan compound represented by general formula (I) with ethylene to obtain an aromatic compound represented by general formula (II) and / or general formula (III). Step (B): A step of oxidizing the aromatic compound represented by general formula (II) and / or general formula (III) obtained in step (A). 【Transformation 6】 [In general formula (I), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 【Transformation 7】 [In general formula (II), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 2 and R 3 are each an alkyl group having 1 to 5 carbon atoms, which may be different from each other, and may be bonded to each other to form a ring structure. 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. 【Transformation 8】 [In general formula (III), R 1 Ha-CH 2 OH, alkyl group having 1 to 5 carbon atoms, —CH 2 O.C.(O.)R. 4 , -C(O)OR 5 R is any one of the groups represented by 4 is an alkyl group having 1 to 5 carbon atoms or an aryl group having 6 to 10 carbon atoms. 5 is a hydrogen atom or an alkyl group having 1 to 5 carbon atoms.

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