JP2011168501A - Aromatic carboxylic ester compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an aromatic carboxylic ester compound that is derived from biomass, can prevent fossil resources from running out and carbon dioxide, i.e. a greenhouse gas from increasing, and can be used as a raw material of a resin instead of a conventional raw material derived from fossil resources, and a method for producing the same. <P>SOLUTION: An aromatic carboxylic ester compound (such as dimethyl terephthalate and 2,6-dimethyl naphthalenedicarboxylate) having a<SP>14</SP>C content of 50.0 pMC (percent Modern Carbon) or higher with respect to the modern reference standard is synthesized from a raw material derived from biomass (such as paracymene and ortho-xylene). <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to an aromatic carboxylic acid ester characterized in that the concentration of ¹⁴ C is 50.0 pMC (percent Modern Carbon) or more with respect to the modern reference standard.

  Most of aromatic carboxylic acid ester compounds are produced using fossil resources such as petroleum, natural gas and coal as raw materials. In recent years, attention has been focused on a method for converting chemical raw materials from biomass resources due to resource problems such as fear of exhaustion of fossil resources and concerns about global warming due to an increase in carbon dioxide concentration.

  As chemical substances not using fossil resources as raw materials but using biomass resources as raw materials, bioethanol obtained by fermenting starch and sugars obtained from corn, sugarcane, sweet potato and the like with microorganisms is known. In addition, as plastics using biomass resources as raw materials, polylactic acid, polyethylene terephthalate using ethylene glycol made of bioethanol as a raw material (for example, see Patent Document 1), biomass-derived 1,3-propanediol ( For example, there are polytrimethylene terephthalate using Patent Document 2 and polybutylene succinate using 1,4-butanediol derived from biomass (for example, see Patent Document 3).

  However, the chemical substances using biomass resources as raw materials are aliphatic compounds, and there are very few examples of aromatic compounds using biomass resources as raw materials. As a method for producing an aromatic compound from biomass resources, a method for producing benzene as an intermediate from methane produced from biomass resources by microbial fermentation and further producing various benzene derivative derivatives (for example, patent documents) 4) is disclosed, but there is no description of specific examples, and its practicality is doubtful. Furthermore, the aromatic compound produced from the biomass resource is the same in appearance as the aromatic compound produced from the fossil resource, and there is a problem that it cannot be determined whether the produced aromatic compound is derived from the biomass resource.

JP 2009-091694 A Special table 2001-505041 gazette Japanese Patent No. 4301918 JP 2004-123666 A

  The present invention provides a biomass-derived aromatic carboxylic acid ester compound that can suppress depletion of fossil resources and an increase in carbon dioxide, which is a greenhouse gas, and can be used as a resin raw material in place of a conventional raw material derived from fossil resources. is there.

As a result of intensive studies in view of the above-described prior art, the present inventors have completed the present invention. That is, the present invention contains an aromatic carboxylic acid ester compound produced from biomass resources in an amount of about 50% by weight or more, and the concentration of ¹⁴ C is 50.0 pMC or more with respect to the modern reference standard. It relates to carboxylic acid esters.

  INDUSTRIAL APPLICABILITY The present invention contributes to the solution of the fossil resource depletion problem and the global warming problem, and can provide a resin raw material having practical physical properties, and its industrial significance is great. For example, when producing dimethyl terephthalate (hereinafter abbreviated as DMT) from fossil resources, 44,725 MJ (mega-joules) of fossil resources are required as raw materials per ton of DMT. It is not necessary to use a fossil resource as a raw material when producing the biomass from biomass resources. Furthermore, since biomass-derived DMT is carbon neutral, carbon dioxide can be reduced by 2.27 tons per ton of DMT when incinerated compared to DMT derived from fossil resources. In addition, when polyethylene terephthalate (hereinafter sometimes abbreviated as PET) is synthesized using this biomass-derived DMT, the amount of fossil resources and carbon dioxide equivalent to the weight of DMT (about 70% by weight) in PET can be reduced. become. Similarly, in the case of dimethyl naphthalenedicarboxylate produced from biomass resources (hereinafter sometimes abbreviated as NDCM), compared to NDCM derived from fossil resources, 2.53 tons per ton NDCM when incinerated. It will be possible to reduce the carbon dioxide. In addition, when polyethylene naphthalate (hereinafter sometimes abbreviated as PEN) is synthesized using this biomass-derived NDCM, the amount of fossil resources and carbon dioxide equivalent to the weight of NDCM (about 75% by weight) in PEN are reduced. It will be possible.

  In the present invention, a biomass resource refers to a carbon-neutral organic resource derived from renewable organisms that is generated from water and carbon dioxide using solar energy by the photosynthesis of plants, and specifically, such as starch and cellulose. It is a resource that excludes fossil resources, including things that have been converted to form, stored, animal bodies that eat and grow plants, and products made by processing plants and animals. Biomass resources are classified into three types: waste, unused, and resource crops, depending on the form of generation. Specifically, biomass resources include cellulosic crops (pulp, kenaf, straw, rice straw, waste paper, papermaking residue, etc.), wood, charcoal, compost, natural rubber, cotton, sugarcane, okara, oil (rapeseed oil, cottonseed oil, Soybean oil, coconut oil, castor oil, etc.), carbohydrate crops (corn, potatoes, wheat, rice, rice husk, rice bran, old rice, cassava, sago palm, etc.), bagasse, buckwheat, soybean, essential oil (pine root oil, orange oil, Eucalyptus oil, etc.), pulp black liquor, food waste, vegetable oil residue, marine product residue, livestock excrement, food waste, wastewater sludge and the like. These biomass resources generally contain a large amount of alkali metals and alkaline earth metals such as nitrogen element, Na, K, Mg, and Ca.

  These biomass resources are not particularly limited, but are induced to carbon sources through known pretreatment and saccharification processes such as chemical treatment with acids and alkalis, biological treatment with microorganisms, physical treatment, and the like. In the present invention, the aromatic carboxylic acid is produced from the raw material of the aromatic carboxylic acid ester compound or the raw material from the biomass resource. If the aromatic carboxylic acid can be produced, the production method is not particularly limited, but a biological treatment method utilizing the action of microorganisms such as fungi and bacteria, acid, alkali, catalyst, thermal energy, light energy Known methods such as chemical treatment methods using the above, physical treatment methods such as miniaturization, compression, microwave treatment, electromagnetic wave treatment and the like can be mentioned. For example, as a method for producing dimethyl terephthalate from bioethanol obtained from saccharides, etc., bioethanol is catalytically converted to an aromatic mixture over a zeolite (H-ZSM-5 type, etc.) catalyst, and the aromatic mixture is distilled. To obtain para-xylene, and the resulting para-xylene is oxidized using a catalyst and then esterified to obtain dimethyl terephthalate, but is not limited thereto.

  The other steps usually include, for example, a micronization step by pretreatment such as chipping, shaving, and crushing of biomass resources, although not particularly limited. If necessary, a grinding process is further included with a grinder or a mill. The biomass resources refined in this way are further guided to a carbon source through pretreatment and saccharification processes, and specific methods include acid treatment and alkali treatment with strong acids such as sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid. , Chemical methods such as ammonia freezing steam explosion method, solvent extraction, supercritical fluid treatment, oxidant treatment, etc., physical methods such as fine grinding, steam explosion method, microwave treatment, electron beam irradiation, microorganisms and enzyme treatment Biological treatment such as hydrolysis may be mentioned.

  Specifically, raw materials for aromatic carboxylic acid ester compounds obtained from biomass resources include alkanes such as methane, alkenes such as ethylene, alkynes such as acetylene, saccharides such as xylose, glucose, cellulose, hemicellulose, methanol and ethanol, Alcohols such as propanol, butanol and glycerol, lignin and isoprene, turpentine oil, α-pinene, limonene, paracymene, 1,8-cineol, terpene compounds such as linalool, bisaborane and caryophyllene, unsaturated fatty acids such as oleic acid and sebacin Examples thereof include linear saturated dibasic acids such as acids.

  Specific examples of aromatic carboxylic acid ester compounds produced from biomass resources include methyl benzoate, dimethyl terephthalate, diethyl terephthalate, diisopropyl terephthalate, di-n-propyl terephthalate, dimethyl isophthalate, and diethyl isophthalate. , Diisopropyl isophthalate, di-n-propyl isophthalate, dimethyl phthalate, diethyl phthalate, diisopropyl phthalate, di-n-propyl phthalate, dimethyl naphthalenedicarboxylate, diethyl naphthalenedicarboxylate, diisopropyl naphthalenedicarboxylate or naphthalenedicarboxyl And di-n-propyl acid. Preferred is dimethyl terephthalate or dimethyl naphthalenedicarboxylate.

Here, the meaning of measuring the radioactive carbon ¹⁴ C in specifying the content ratio of the biomass-derived component in the present invention will be described below. The concentration measurement of ¹⁴ C is performed by an accelerator mass spectrometry (AMS) combining a tandem accelerator and a mass spectrometer (specifically, ¹² C, ¹³ C, ¹⁴ C) is physically separated by using an atomic weight difference with an accelerator, and the abundance of each isotope atom is measured.

In 1 mole of carbon atoms (6.02 × 10 ²³ ) there are about 6.02 × 10 ^{11 14} C, which is about one trillionth of a normal carbon atom. ¹⁴ C is called a radioisotope and its half-life regularly decreases at 5730 years. It takes 26,000 years for all of these to collapse. Therefore, fossil fuels such as coal, oil, and natural gas, which are considered to have passed over 26,000 years after carbon dioxide in the atmosphere has been taken into plants and immobilized, are initially fixed. All of the ¹⁴ C elements that have been included in the earth have collapsed and are not included at all in the 21st century. Therefore, chemical substances produced using these fossil fuels as a raw material do not contain any ¹⁴ C element. On the other hand, ¹⁴ C is a cosmic ray that undergoes a nuclear reaction in the atmosphere, is constantly generated, and balances with a decrease due to radiation decay. The amount of ¹⁴ C is constant in the earth's atmospheric environment.

On the other hand, if the carbon dioxide in the atmosphere has been immobilized incorporated such animals eat the plants and which in its captured state, ^{14 C} without newly replenished, half of ^{14 C} According to the period, the ¹⁴ C concentration decreases at a constant rate with time. For this reason, by analyzing the ¹⁴ C concentration in the aromatic carboxylic acid ester compound, it is possible to easily determine whether it is made from fossil resources or from aromatic carboxylic acid ester compounds made from biomass resources. It becomes. Also this ¹⁴ C concentration was ¹⁴ C-concentration in the circulating carbon in natural time 1950 with modern standard reference, it is common practice to use the criteria for the ¹⁴ C concentration is 100%. The present ¹⁴ C concentration measured in this way is a value of about 110 pMC, and if the substance used as a sample is manufactured with a substance derived from 100% natural (biological), It is known to show a value of about 110 pMC. On the other hand, when this ¹⁴ C concentration is measured using a petroleum-based (fossil-based) derived material, it shows almost 0 pMC. Using these values, the mixing ratio of naturally derived system-fossil derived system can be calculated. Furthermore, it is preferable to use an oxalic acid standard issued by NIST (National Institute of Standards and Technology) as the standard standard reference for the ¹⁴ C concentration. The specific radioactivity of carbon in this oxalic acid ( ¹⁴ C radioactivity intensity per gram of carbon) is separated for each carbon isotope, corrected to a constant value for ¹³ C, and corrected for attenuation from 1950 AD to the measurement date The value subjected to is used as the standard ¹⁴ C concentration value. In the aromatic carboxylic acid ester compound of the present invention, this ¹⁴ C concentration ratio needs to be 50.0 pMC or more. Preferably it is 52.0 pMC or more.

The analytical method for the ¹⁴ C concentration in the aromatic carboxylic acid ester compound first requires pretreatment of the aromatic carboxylic acid ester compound. Specifically, the carbon contained in the aromatic carboxylic acid ester compound is oxidized and converted into carbon dioxide. Further, the obtained carbon dioxide is separated from water and nitrogen, and the carbon dioxide is subjected to a reduction treatment and converted into graphite which is solid carbon. To this resulting graphite is irradiated with cations such as Cs ⁺ to generate negative ions of carbon, accelerated carbon ions using tandem accelerator, is charged converted from negative ions to positive ions, the mass analysis electromagnet ¹² C ³⁺ , ¹³ C ³⁺ , and ¹⁴ C ³⁺ traveling orbits are separated, and ¹⁴ C ³⁺ is measured by an electrostatic analyzer. Since each isotope atom can be measured one by one, it is characterized in that a highly accurate measurement can be performed with a small amount of sample that is 1/1000 or less of the conventional amount.

  In addition, it shows below about the manufacturing method of the aromatic carboxylic acid ester compound of this invention. In the implementation of the production method of the present invention, as raw materials for forming the aromatic portion, aliphatic alcohols, olefins, cyclic terpenes, unsaturated fatty acids, linear saturated dibasic acids, etc. synthesized from biomass are used. Can be used. Specific examples of the aliphatic alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, tert-butanol, pentanol, hexanol, octanol, decanol, allyl alcohol, benzyl alcohol, Examples thereof include alcohols such as ethylene glycol, propylene glycol, butylene glycol (tetramethylene glycol, butanediol), glycerol, diglycerol, pentaerythritol, dipentaerythritol, and terpene alcohol compounds such as linalool and geraniol. Specific examples of olefins include ethylene, propylene, butene, 1,2-butadiene, 1,3-butadiene, 1,3-pentadiene, 1,4-pentadiene, and isooctene. Specific examples of the cyclic terpenes include α-pinene, β-pinene, limonene, paracymene, 1,8-cineol, 1,4-cineole and the like. Specific examples of the unsaturated fatty acid include oleic acid. Specific examples of the linear saturated dibasic acid include sebacic acid. Ortho-xylene and meta-xylene can also be used when producing an aromatic compound having two or more rings or an aromatic compound having a polycondensed ring. Among these compound groups, cyclic terpenes are preferable. More preferred is paracymene, since paracymene has a benzene skeleton in its structure and can be used as it is in an oxidation reaction.

  In the implementation of the production method of the present invention, as the alcohol used for the transesterification reaction, either one synthesized from a fossil resource or one synthesized from a biomass resource can be used, but in the aromatic carboxylic acid ester compound, For the purpose of increasing the content ratio of biomass-derived components, it is preferable to use alcohols synthesized from biomass resources. Specific examples of alcohols include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, sec-butanol, and tert-butanol, with methanol being preferred.

  As a method of producing an aromatic carboxylic acid ester compound from aliphatic alcohols synthesized from biomass resources as raw materials, xylene is produced by contacting aliphatic alcohols synthesized from biomass resources with zeolite, Examples include a method of oxidizing and then esterifying the obtained xylene, a method of oxidizing and then esterifying the paracymene of cyclic terpenes synthesized from biomass resources. The zeolite to be used is not particularly specified, and examples thereof include a pentasil type, a mordenite type, and a faujasite type, and the H-ZSM-5 type among the pentasil types is particularly preferable. In order to adjust the pore diameter of the zeolite, supporting a single metal such as platinum or zinc in the zeolite is effective for increasing the amount of the aromatic compound to be generated. The amount of zeolite used is 1 part by weight or more per 10 parts by weight of the starting aliphatic alcohol. More preferably, it is 2 parts by weight or more and 6 parts by weight or less with respect to 10 parts by weight of the aliphatic alcohol. If the amount of zeolite to be used is less than 1 part by weight, the amount of aromatic compound to be produced is reduced, which is not preferable. If it exceeds 10 parts by weight, side reactions are likely to occur and the yield of xylene is reduced. The pressure when the zeolite and the aliphatic alcohol are in contact may be either pressurized or normal pressure, but the reaction temperature when the zeolite and the aliphatic alcohol are in contact is 300 ° C. or more and 500 ° C. or less. Preferably it is 350-450 degreeC. If the reaction temperature is not 300 ° C. or higher, the amount of aromatic compound produced is reduced. On the other hand, if the reaction temperature exceeds 500 ° C., a large amount of heat energy is used, which is inefficient. In addition, side reactions are likely to occur, and the yield of aromatic compounds decreases.

  On the other hand, when paracymene is used as a raw material, since an aromatic ring has already been formed, an aromatic carboxylic acid compound can be obtained by oxidizing an alkyl group directly bonded to the aromatic ring by a commonly used oxidation reaction. it can. Further, the obtained aromatic carboxylic acid compound is subjected to an esterification reaction in the presence of a lower alcohol such as methanol, ethanol, propanol, or butanol and an acid catalyst by an ordinary method to obtain an aromatic carboxylic acid ester compound. be able to. When esterifying an aromatic carboxylic acid compound and a lower alcohol, it may be necessary to select conditions to be performed under conditions of high temperature and pressure. In such a case, a method may be adopted in which an esterification reaction is once carried out with a dihydroxy compound such as ethylene glycol and then reacted with the above-mentioned lower alcohol in the presence of a transesterification catalyst. This method of producing via paracymene can be preferably employed for producing an ester compound of terephthalic acid because terephthalic acid can be produced relatively easily.

Hereinafter, the content of the present invention will be described more specifically with reference to examples, but the present invention is not limited thereto. In addition, what is called "part" in an Example and a comparative example represents a weight part. Moreover, the carboxylic acid ester compound manufactured from the fossil resource refers to the carboxylic acid ester compound manufactured using fossil resources, such as petroleum, natural gas, or coal, which are usually manufactured industrially.
The product was analyzed with a gas chromatograph, a liquid chromatograph, and a gas chromatograph mass spectrometer.
¹⁴ C concentration comparison (pMC: percent Modern Carbon) was measured by the above-described accelerator mass spectrometry (AMS) using ¹⁴ C in the circulating carbon as of 1950 as a reference (100%).

[Example 1]
300 parts by weight of Yashara Chemical Co., Ltd., 501 parts by weight of acetic acid, 1.059 parts by weight of cobalt acetate as a catalyst, and 1.101 parts by weight of manganese acetate, which are synthesized from biomass (orange peel and pulp black liquor). While adding 1.317 parts by weight of lithium bromide to a titanium autoclave, adjusting the pressure in the reaction system to 1.5 MPa with a reaction temperature of 180 ° C. and compressed air, and supplying compressed air to the reactor, 5 The reaction was stirred for an hour. After the reaction, the reaction solution was subjected to suction filtration to separate into solid and liquid, and the obtained solid was washed and filtered twice with pure water and dried at 90 ° C. overnight to obtain 240 parts by weight of terephthalic acid.

  240 parts by weight of the obtained terephthalic acid, 720 parts by weight of ethylene glycol, and 6 parts by weight of potassium carbonate as a catalyst were charged into a three-necked flask and reacted while stirring at a reaction temperature of 200 ° C. and normal pressure for 4 hours. Thereafter, 400 parts by weight of ethylene glycol was distilled from the reaction liquid, and the biomass derived from biomass obtained by liquefying and purifying with copper zinc catalyst after gasifying rice straw and wood into the reaction liquid after the ethylene glycol distillation. 730 parts by weight and 7.2 parts by weight of sodium carbonate as a catalyst were added and reacted for 1 hour while refluxing methanol. After the reaction, the reaction solution was subjected to suction filtration to separate into solid and liquid, and the obtained solid was washed and filtered three times with methanol and dried at 90 ° C. overnight. Furthermore, 135 parts by weight of dimethyl terephthalate was obtained by purifying the dried solid by distillation.

When 10 parts by weight of dimethyl terephthalate produced from the above biomass resources was collected, converted into graphite and analyzed by accelerator mass spectrometry, the ¹⁴ C concentration was 106.9 pMC. The ¹⁴ C concentration is relative to the modern reference standard, and oxalic acid issued by the National Institute of Standards and Technology was used as the modern reference standard. The results are shown in Table 1.

[Example 2]
In Example 1, it carried out similarly to Example 1 except having used what mixed the parasite which originated in biomass and the parasite which originated in the fossil resource in an equal amount. When 10 parts by weight of the synthesized dimethyl terephthalate was collected and analyzed in the same manner as in Example 1, the ¹⁴ C concentration was 52.8 pMC. The results are shown in Table 1.

[Comparative Example 1]
In Example 1, it carried out like Example 1 except having used only the fossil resource-derived paracymene as a paracymene. When 10 parts by weight of the synthesized dimethyl terephthalate was collected and analyzed in the same manner as in Example 1, the ¹⁴ C concentration was <0.06 pMC. The results are shown in Table 1.

[Example 3]
30 parts by weight of zirconium oxide powder was added to an aqueous solution containing 5 parts by weight of potassium hydroxide, and impregnated with stirring at 50 ° C. for 1 hour. Water was distilled off at 70 ° C. under reduced pressure, dried at 110 ° C. for a whole day and night, and further fired at 500 ° C. in air. 6 parts by weight of the catalyst thus obtained was charged into a three-necked flask, stirred at 180 ° C. in a nitrogen atmosphere, 0.3 parts by weight of metallic sodium was added thereto, and stirred at that temperature for 60 minutes. Biomass obtained by subjecting ethanol obtained by fermentation from corn to an aromatization reaction using H-ZSM-5 type zeolite as a catalyst in the reaction vessel, and distilling and purifying the resulting aromatic mixture 600 parts by weight of ortho-xylene derived therefrom was supplied and heated to 140 ° C. Further, 35 parts by weight of biomass-derived 1,3-butadiene obtained by dehydrating 1,4-butanediol obtained from corn by fermentation using corn was introduced in 1 hour with stirring. Reacted. After completion of the reaction, the reaction mixture was cooled, and the catalyst and the liquid phase were separated to obtain 630 parts by weight of the liquid phase. The obtained liquid phase was distilled and purified to obtain 80 parts by weight of 5-o-tolylpentene-2.

  500 parts by weight of pure water was added to 15 parts by weight of H-type mordenite manufactured by Tosoh Corporation, 270 parts by weight of silica, and 21 parts by weight of alumina sol having an alumina content of 70% by weight as a binder, followed by mixing and stirring at room temperature. Then, after shaping | molding using an extrusion molding machine, it dried at 110 degreeC and baked at 350 degreeC for 3 hours, and prepared the catalyst. 10 parts by weight of this catalyst was filled in a glass flow-type reaction vessel, this catalyst layer was heated to a reaction temperature of 170 ° C. under normal pressure, and 10 parts by weight of 5-o-tolylpentene-2 synthesized by the above method was added per hour. The reaction was carried out by supplying nitrogen at 100 mL / min, and the product was cooled and collected. A product obtained by distilling this product and removing high boilers is supplied to a glass flow-through reaction vessel filled with 40 parts by weight of 1% platinum / activated carbon catalyst (manufactured by NEM Catcat) at 10 parts by weight per hour. And reacted at a reaction temperature of 280 ° C. to obtain 1,5-dimethylnaphthalene.

  1,5-dimethylnaphthalene obtained by the above-described method was used at a reaction temperature of 220 ° C., WHSV = 1.0, atmospheric pressure solution using a catalyst (alumina content 20% by weight) of H-type mordenite manufactured by Tosoh Corporation. The reaction was carried out by a phase flow system, and the product was purified by recrystallization using normal heptane to obtain 2,6-dimethylnaphthalene.

  Acetic acid 288.9 parts by weight, water 3.2 parts by weight, cobalt acetate (tetrahydrate) 0.63 parts by weight, manganese acetate (tetrahydrate) 5.37 parts by weight, hydrogen bromide (47% aqueous solution) 1 A catalyst solution was prepared by mixing and dissolving 92 parts by weight. Next, 120 parts by weight of the above catalyst solution is charged into a titanium autoclave, and the remaining 180 parts by weight of the catalyst solution is mixed with 30 parts by weight of 2,6-dimethylnaphthalene synthesized by the above method and charged into a raw material supply tank and heated. Then, 2,6-dimethylnaphthalene was dissolved to prepare a raw material solution. The pressure in the reaction system was adjusted to 1.8 MPa with nitrogen and heated to 200 ° C. with stirring. After the temperature and pressure were stabilized, the raw material liquid and compressed air were supplied to the reactor to initiate the oxidation reaction. The raw material liquid was continuously supplied over 1 hour while adjusting the supply air flow rate so that the oxygen concentration in the exhaust gas was 2% by volume. After the supply of the raw material liquid was completed, the air supply was continued for 9 minutes. After the reaction, the reaction solution is subjected to suction filtration to separate into solid and liquid, and the obtained solid is washed and filtered with 80 parts by weight of acetic acid containing 20% by weight of water, dried at 90 ° C. overnight, and 2,6-naphthalene dicarboxylic acid. 40.65 parts by weight of acid were obtained.

50 parts by weight of 2,6-naphthalenedicarboxylic acid synthesized by the above method, 5 parts by weight of sulfuric acid, rice straw and wood were gasified and then liquefied and purified with a copper zinc catalyst, and 500 parts by weight of biomass-derived methanol was glass. The reaction mixture was charged into a manufactured autoclave and allowed to react with stirring at a reaction temperature of 130 ° C. and a pressure of 1.3 MPa for 3 hours. After the reaction, the reaction solution was subjected to suction filtration to separate into solid and liquid, and the obtained solid was washed and filtered three times with methanol and dried at 90 ° C. overnight. Furthermore, 30 parts by weight of dimethyl 2,6-naphthalenedicarboxylate was obtained by purifying the dried solid by distillation.
When 10 parts by weight of dimethyl 2,6-naphthalenedicarboxylate produced from the above biomass resources was collected, converted to graphite and analyzed by accelerator mass spectrometry, the ¹⁴ C concentration was 103.5 pMC. The results are shown in Table 1.

  By using the biomass-derived aromatic carboxylic acid ester compound obtained by the present invention in place of the conventional fossil resource-derived aromatic carboxylic acid ester compound, depletion of fossil resources and an increase in carbon dioxide, which is a greenhouse gas, are suppressed. Yes, its industrial significance is great.

Claims (5)

The aromatic carboxylic acid ester compound, wherein the concentration of ¹⁴ C relative to the modern reference standard in the aromatic carboxylic acid ester compound is 50.0 pMC or more.   The aromatic carboxylic acid ester compound according to claim 1, wherein the aromatic carboxylic acid ester compound is dimethyl terephthalate.   The aromatic carboxylic acid ester compound according to claim 1, wherein the aromatic carboxylic acid ester compound is dimethyl naphthalenedicarboxylate.   The method for producing an aromatic carboxylic acid ester compound according to claim 2, wherein paracymene is used as a raw material.   The method for producing an aromatic carboxylic acid ester compound according to claim 3, wherein ortho-xylene is used as a raw material.