KR20230100632A - Furan dicarboxylic acid compound, method for preparing furan dicarboxylic acid compound, polyester, and mehtod for preparing polyester - Google Patents

Abstract

Provided is a method for manufacturing furandicarboxyl acid-based compound comprising the following steps: manufacturing a hydroxyl furfural compound from a hydroxyl-free furfural compound; and manufacturing a furandicarboxylic acid-based compound by oxidizing the hydroxyl furfural compound in the presence of a heterogeneous catalyst.

Description

Furandicarboxylic acid compound, method for producing furandicarboxylic acid compound, polyester, and method for producing polyester

The present invention relates to a method for producing a furandicarboxylic acid-based compound, a furandicarboxylic acid-based compound prepared thereby, a method for producing polyester, and a polyester produced thereby.

In order to reduce greenhouse gases, developed countries such as the United States and Europe are strengthening carbon dioxide emission regulations. Therefore, there is an increasing demand for the biochemical industry that can reduce dependence on existing fossil raw material resources and reduce greenhouse gases. In other words, the chemical industry is changing from petroleum-dependent to bio-dependent.

For example, technology for replacing polyethylene terephthalate (PET), which is mainly used as a beverage bottle or food storage container, with bio-PET is being actively researched.

A dicarboxylic acid aromatic heterocyclic compound useful as a monomer in the production of bio-PET is a derivative usually prepared by oxidizing 5-hydroxymethyl furfural (HMF). Since 5-hydroxymethylfurfural is obtained from sugar, it is a derivative of a widely available raw material in nature.

For reference, as shown in Scheme 1, the oxidation reaction for 5-hydroxymethylfurfural is 2,5-furandicarboxylic acid (FDCA) and 2-carboxy-5-formyl furan (5- Aromatic heterocyclic compounds of monocarboxylic acids or dicarboxylic acids including formyl-2-furoic acid (FFCA) can be obtained as main products.

[Scheme 1]

Processes for the oxidation of 5-hydroxymethylfurfural, from which aromatic heterocyclic compounds of monocarboxylic acids or dicarboxylic acids can be obtained as main products, are known from the literature. For example, U.S. Pat. No. 4,977,283 (Hoechst) describes a method for oxidation of 5-hydroxymethylfurfural in an aqueous environment with a metal catalyst belonging to the platinum group.

In addition, US Patent Publication No. 2008-0103318 (Battelle) describes a method for oxidation of 5-hydroxymethylfurfural catalyzed by platinum supported on a support.

However, the above oxidation methods of 5-hydroxymethylfurfural are expensive to produce, and are carried out in a batch reaction. In such a batch reaction, input of raw materials, heating to the reaction temperature, and reaction It requires time substantially unrelated to the reaction, such as discharging the product, and there is a problem in that the productivity of the reactor is lowered.

In addition, in order to repeatedly use the catalyst, a separation process between the catalyst and the product is required, and there is a problem in that the activity of the catalyst is deteriorated prematurely due to a change in temperature or the like.

On the other hand, 2,5-furandicarboxylic acid produced by oxidation of 5-hydroxymethylfurfural is a compound with low thermal stability, and in the process of producing polyester by esterifying it with a diol component, yellowing, browning, etc. , and 2-carboxy-5-formyl furan generated in the oxidation process of 5-hydroxymethylfurfural is the main discoloration factor of polyester.

US Patent No. 4,977,283 (December 11, 1990) US Patent Publication No. 2008-0103318 (May 1, 2008)

In one embodiment, while preparing a furandicarboxylic acid-based compound using a heterogeneous catalyst, discoloration of polyester can be prevented by removing impurities that cause discoloration of polyester, and polyester having a higher molecular weight can be produced. It is an object of the present invention to provide a method for producing a furandicarboxylic acid-based compound that can be used.

Another embodiment aims to provide a furandicarboxylic acid-based compound prepared by a method for preparing a furandicarboxylic acid-based compound.

Another object of the present invention is to provide a method for producing polyester using a furandicarboxylic acid-based compound.

Another embodiment aims to provide a polyester produced by a method for producing polyester.

According to one embodiment, preparing a hydroxyl furfural compound from a hydroxyl-free furfural compound, and preparing a furandicarboxylic acid-based compound by oxidizing the hydroxyl furfural compound in the presence of a heterogeneous catalyst It provides a method for producing a furandicarboxylic acid-based compound comprising.

Hydroxyl-free furfural compounds include chloromethyl furfural (CMF), 2,5-diformylfuran (DFF), 5-acetoxymethylfurfural (AMF), or mixtures thereof.

The hydroxyl furfural compound may include 5-hydroxymethyl furfural (HMF), 5-hydroxymethylfurfural ester, 5-hydroxymethylfurfural ether, or mixtures thereof.

In the step of preparing the hydroxyl furfural compound, a solution containing a hydroxyl-free furfural compound and a solvent is stirred at 100 rpm to 500 rpm at 20 ° C. to 90 ° C. for 1 minute to 60 minutes, followed by a conversion reaction It can be done.

After the conversion reaction, using an extraction solvent containing ethyl acetate (EA), methyl isobutyl ketone, diethyl ether, chloroform, water, or a mixture thereof Hydroxyl furfural compounds can be extracted.

The extraction solvent may be removed by volatilization at 5 °C to 30 °C under reduced pressure to 10 Torr to 40 Torr.

The method for preparing the furandicarboxylic acid-based compound may further include adding a solvent to the prepared hydroxyl furfural compound and then filtering to remove humin.

The oxidation reaction can be effected by contacting a solution comprising a hydroxyl furfural compound and a solvent with an oxidizing agent in the presence of a solid base and a heterogeneous catalyst.

The heterogeneous catalyst may include an active metal including Fe, Ni, Ru, Rh, Pd, Os, Ir, Au, Pt, an alloy thereof, or a mixture thereof, and a carrier supporting the active metal.

The heterogeneous catalyst may contain up to 600 moles based on the active metal in the catalyst per mole of the hydroxyl furfural compound.

The solid base may include MgO, CaO, CaCO ₃ , hydrotalcite, or mixtures thereof.

The solid base may be included in an amount of 10 parts by weight to 40 parts by weight based on 100 parts by weight of the hydroxyl furfural compound.

The oxidizing agent may include oxygen, air, or mixtures thereof.

The solvent may include water, acetonitrile, acetone, dimethylformamide, dimethylsulfoxide, ethanol, methanol, t-butyl hypochlorite, or mixtures thereof.

The solvent may be included in an amount of 1000 parts by weight to 9000 parts by weight based on 100 parts by weight of the hydroxyl furfural compound.

The oxidation reaction may be performed for 1 hour to 24 hours at a pressure of 6 bar to 50 bar and a temperature of 80 °C to 200 °C.

Products of the oxidation reaction may include 2,5-furandicarboxylic acid (FDCA) and 5-formylfurancarboxylic acid (FFCA).

The method for producing a furandicarboxylic acid-based compound may further include a purification step of removing 5-formylfurancarboxylic acid by contacting a product of the oxidation reaction with hydrogen in the presence of a heterogeneous reduction catalyst and a solvent.

The purification step may be performed at 5 bar to 15 bar and 100 °C to 200 °C for 1 hour to 10 hours.

The heterogeneous reduction catalyst may include an active metal including Cu, Ni, Co, Pd, Pt, Ru, Ag, Au, Rh, Os, Ir, an alloy thereof, or a mixture thereof, and a carrier supporting the active metal. can

The method for producing a furandicarboxylic acid-based compound may further include a metal purification step of removing a metal component from an oxidation reaction product.

The metal component is Fe, Cr, Ni, Cu, Zn, Mo, Ti, Cd, Co, Mn, Na, Mg, K, Ca, Al, As, Sb, Pb, Sn, B, Si, or mixtures thereof. can include

The metal purification step may be performed using an ion filter.

According to another embodiment, a furandicarboxylic acid-based compound prepared according to a method for preparing a furandicarboxylic acid-based compound and containing less than 200 ppm of a metal component with respect to the total weight is provided.

The furandicarboxylic acid-based compound may include 3% by weight or less of humin based on the total weight.

Furandicarboxylic acid-based compounds are 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or mixtures thereof in an amount of less than 10% by weight.

According to another embodiment, a method for producing polyester is provided, which includes preparing polyester by esterifying a furandicarboxylic acid-based compound and a diol-based compound, followed by polymerization.

According to another embodiment, it includes a repeating unit represented by Formula 7 below, contains less than 200 ppm of a metal component with respect to the total weight, and has a b* value of 14 or less according to the CIE1976 L*a*b* colorimeter. , polyester.

[Formula 7]

In Formula 7, A ¹¹ is a straight-chain or branched-chain divalent hydrocarbon group having 1 to 15 carbon atoms, R ¹¹ is a halogen group, a hydroxyl group, an alkoxy group, or an alkyl group, n ¹¹ is the number of repetitions of a repeating unit, and n ¹² is an integer from 0 to 2.

Metal includes Fe, Cr, Ni, Cu, Zn, Mo, Ti, Cd, Co, Mn, Na, Mg, K, Ca, Al, As, Sb, Pb, Sn, B, Si, or mixtures thereof can do.

The polyester may contain less than 3% by weight of humin based on the total weight.

The polyester is 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or mixtures thereof, by weight. It may contain less than 10% by weight.

Polyester may have an L* value of 93 or more, an a* value of -0.5 to 0, and a b* value of 14 or less according to the CIE1976 L*a*b* color difference system.

According to the method for producing a furandicarboxylic acid-based compound according to an embodiment, while preparing a furandicarboxylic acid-based compound using a heterogeneous catalyst, discoloration of polyester is prevented by removing impurities that cause discoloration of polyester. can be made, and polyesters with higher molecular weight can be prepared.

Polyester according to another embodiment has improved color (yellowness) and a narrow molecular weight distribution range as the molecular weight increases, so it has excellent strength and uniform molecular weight.

1 is a graph showing the results of analyzing 2,5-furandicarboxylic acid prepared in Example 1 using high-performance liquid chromatography (HPLC).
2 is a graph showing the results of analyzing 2,5-furandicarboxylic acid prepared in Comparative Example 1 using high performance liquid chromatography (HPLC).
3 is a graph showing the results of analyzing 2,5-furandicarboxylic acid prepared in Comparative Example 2 using high performance liquid chromatography (HPLC).
4 is a graph showing the results of analyzing 2,5-furandicarboxylic acid prepared in Comparative Example 3 using high-performance liquid chromatography (HPLC).
5 is a graph showing the results of analyzing 2,5-furandicarboxylic acid prepared in Comparative Example 4 using high-performance liquid chromatography (HPLC).

Advantages and characteristics of the techniques described below, and methods of achieving them, will become clear with reference to the embodiments described later in detail. However, the implemented form may be not limited to the embodiments disclosed below. Unless otherwise defined, all terms (including technical and scientific terms) used in this specification may be used with meanings commonly understood by those skilled in the art. In addition, terms defined in commonly used dictionaries are not interpreted ideally or excessively unless explicitly specifically defined. When it is said that a certain part "includes" a component throughout the specification, this means that it may further include other components, not excluding other components unless otherwise stated. In addition, singular forms also include plural forms unless specifically stated otherwise in a phrase.

A method for preparing a furandicarboxylic acid-based compound according to an embodiment includes a conversion reaction step of preparing a hydroxyl furfural compound from a hydroxyl-free furfural compound, and an oxidation reaction of the hydroxyl furfural compound in the presence of a heterogeneous catalyst. It includes an oxidation reaction step of preparing a furandicarboxylic acid-based compound.

The hydroxyl-free furfural compound may be a raw material for an aromatic heterocyclic compound represented by Formula 1 below.

[Formula 1]

The aromatic heterocyclic compound raw material represented by Chemical Formula 1 is a compound converted from wood, and is a compound that is first used in the production of a furandicarboxylic acid-based compound. For example, the aromatic heterocycle may include furan, thiophene, pyrrole, or a combination thereof.

In Formula 1, any one of R ¹ and R ² is an aldehyde group, and the other is a hydrogen group, a hydroxyl group, an aldehyde group, an acetoxy group, a halogen group, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group, or a substituted or unsubstituted may be a C ₁ -C ₂₀ alkoxy group. That is, in Formula 1, when R ¹ is an aldehyde, R ² is a hydrogen group, a hydroxyl group, an aldehyde group, an acetoxy group, a halogen group, a substituted or unsubstituted C ₁ -C ₂₀ alkyl group, or a substituted or unsubstituted C ₁ - It may be a C ₂₀ alkoxy group. Also, for example, a C ₁ -C ₂₀ alkyl group or a C ₁ -C ₂₀ alkoxy group may be unsubstituted or substituted with one or more halogen atoms.

For example, the hydroxyl-free furfural compound may include compounds represented by Chemical Formulas 2 to 4, or combinations thereof. That is, hydroxyl-free furfural compounds include chloromethyl furfural (CMF), 2,5-diformylfuran (DFF), 5-acetoxymethylfurfural (AMF) ), or mixtures thereof.

[Formula 2]

[Formula 3]

[Formula 4]

The hydroxyl furfural compound may include 5-hydroxymethyl furfural (HMF), 5-hydroxymethylfurfural ester, 5-hydroxymethylfurfural ether, or a mixture thereof, for example For example, 5-hydroxymethylfurfural can be represented by Formula 5.

[Formula 5]

In the conversion reaction step, a hydroxyl furfural compound is prepared from a hydroxyl-free furfural compound.

For example, the conversion reaction may be performed by stirring after mixing with a solvent.

The solvent may include water, acetonitrile, acetone, dimethylformamide, dimethyl sulfoxide, ethanol, methanol, t-butyl hypochlorite, or mixtures thereof. For example, when water is used, OH ^- A hydroxyl-free furfural compound can be converted to 5-hydroxymethylfurfural by donation. In addition, since the hydroxyl-free furfural compound is hydrophobic when it is chloromethylfurfural and does not dissolve well in water, it may be well soluble in water by mixing some polar organic solvents.

Agitation of the conversion reaction may be between 100 rpm and 500 rpm, for example between 150 rpm and 350 rpm. If the stirring of the conversion reaction is less than 100 rpm, it may be difficult to convert the hydroxyl-free furfural compound into a hydroxyl furfural compound because it is not sufficiently stirred in the solvent, and if it exceeds 500 rpm, the solvent of the stirrer Due to the heat of friction with the stirrer, excessive temperature rise at the contact surface of the reactant may cause huminization to proceed, resulting in a decrease in yield.

The conversion reaction may be performed at 20 °C to 90 °C, for example, 40 °C to 90 °C. If the temperature of the conversion reaction is less than 20 ° C, the reaction may not proceed, and if it exceeds 90 ° C, self-polymerization occurs due to high temperature after conversion to a hydroxyl furfural compound, resulting in dimers, trimers, Yield may decrease due to the formation of humin.

The conversion reaction can be carried out for 1 minute to 60 minutes, for example 2 minutes to 30 minutes. If the conversion reaction time is less than 1 minute, the reaction may not be initiated, and if it exceeds 60 minutes, dimers, trimers, and humin may be produced, resulting in a decrease in yield.

For example, when the hydroxyl-free furfural compound is chloromethylfurfural, in the conversion reaction, chlorine becomes chloride ion and meets hydrogen ion (H ⁺ ) of water to form HCl, A hydroxyl ion (OH-) is substituted at the Cl ^- site to give 5-hydroxymethylfurfural.

Optionally, after the conversion reaction, a step of extracting the resulting hydroxyl furfural compound may be further included.

Extraction of the resulting hydroxyl furfural compound includes ethyl acetate (EA), methyl isobutyl ketone, diethyl ether, chloroform, water, or a mixture thereof It can be made using an extraction solvent that does.

In addition, after selectively extracting the hydroxyl furfural compound, a step used for extraction may be further included.

For example, the extraction step may further include the step of extracting the hydroxyl furfural compound and then volatilizing and removing the extraction solvent while reducing the pressure to 10 Torr to 40 Torr at 5 °C to 30 °C.

When the extraction solvent is removed, if the temperature is less than 5 ° C, the extraction solvent is not volatilized and some may remain in the hydroxyl furfural compound, and if it exceeds 30 ° C, the internal temperature rises rapidly according to the internal pressure, resulting in Yield may decrease as self-polymerization proceeds.

When removing the extraction solvent, it is not easy to maintain the pressure below 10 Torr, and when the pressure exceeds 40 Torr, the extraction solvent may not be completely volatilized and some of the hydroxyl furfural compound may remain.

Optionally, a step of removing humin from the resulting hydroxyl furfural compound may be further included.

5-Hydroxymethylfurfural is unstable at acidic pH, high temperature, etc., and 5-hydroxymethylfurfural is polymerized with each other or with reaction starting materials or reaction by-products, so that it is soluble or insoluble depending on the chain length, and turns brown in the reaction solution. It can produce humins that cause discoloration up to black. Here, the reaction starting material is chloromethyl furfural (CMF), 2,5-diformylfuran (2,5-diformylfuran, DFF), 5-acetomethyl furfural (5-acetoxymethylfurfural, AMF), or these It may be a mixture of, and the reaction by-product is 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or these may be a mixture of

For example, the step of removing humin may be performed by adding a solvent to the hydroxyl furfural compound and then filtering.

The solvent may include water, acetonitrile, acetone, dimethylformamide, dimethylsulfoxide, ethanol, methanol, t-butyl hypochlorite, or mixtures thereof.

Filtration may be performed, for example, at room temperature and under normal pressure.

In the oxidation reaction step, a furandicarboxylic acid-based compound is prepared by oxidizing a hydroxyl furfural compound in the presence of a heterogeneous catalyst.

For example, the oxidation reaction may be performed by contacting a solution containing a hydroxyl furfural compound and a solvent with an oxidizing agent in the presence of a solid base and a heterogeneous catalyst.

The heterogeneous catalyst may include an active metal and a carrier supporting the active metal.

The active metal has an activity that contributes to improving product yield when preparing a furandicarboxylic acid-based compound from a hydroxyl furfural compound.

The active metal may include Fe, Ni, Ru, Rh, Pd, Os, Ir, Au, Pt, or combinations thereof, which may have various oxidation states, such as Ru, Pd, Pt, or Au. can include

The heterogeneous catalyst may include 0.1 wt% to 10 wt% of the active metal, for example, 0.1 wt% to 5 wt%, based on the total weight of the heterogeneous catalyst. If the content of the active metal is less than 0.1% by weight, the oxidation reaction may not proceed, and if it exceeds 10% by weight, there may be economic loss due to the unnecessary content because it is more than the amount required for the reaction in the continuous process reaction. The active metal may not be uniformly deposited on the active metal and may be aggregated with each other.

The carrier may include metal oxides, carbonaceous materials, metal silicates, metal carbides, or mixtures thereof. The metal oxide may include, for example, silica, zirconia, alumina, or mixtures thereof. The carbonaceous material may be, for example, carbon black.

For example, the carrier may be a basic metal oxide carrier. The basic metal oxide support includes a basic metal oxide capable of forming a complex by coordinating with a hydroxyl furfural compound.

For example, a furandicarboxylic acid-based compound may be prepared by oxidizing a hydroxyl furfural compound in a polar solvent in the presence of a heterogeneous catalyst. It must exist in a liquid state so that it does not precipitate in the reactor. At this time, the basic metal oxide coordinates with the furandicarboxylic acid-based compound and serves to maintain the product in a liquid phase until the reaction is completed.

Basic metal oxides capable of forming complexes by coordinate bonding with furandicarboxylic acid compounds include BaO, Nd ₂ O ₃ , Cs ₂ O, CsX (X is OH, Cl, Br, or I), basic zeolites, Basic complex metal oxides, metal-organic frameworks (MOFs), hydrotalcite, hydroxyapatite, or combinations thereof may be included.

For example, in the basic zeolite, the hydrogen of a silica/alumina (SiO ₂ /Al ₂ O ₃ ) molar ratio of 20 to 1000 is Na, K, Rb, Cs, Mg, Ca, Sr, It may be a zeolite substituted with an ion containing Ba, or a combination thereof.

For example, the basic composite metal oxide is Mg ₂ Al ₂ O ₄ , ZnAl ₂ O ₄ , BaTiO ₃ , ZnTiO ₃ , MgO-SiO ₂ , CaO-SiO ₂ , SrO-SiO ₂ , BaO-SiO ₂ , MgO-Al ₂ O ₃ , CaO-Al ₂ O ₃ , SrO-Al ₂ O ₃ , BaO-Al ₂ O ₃ , MgO-TiO ₂ , CaO-TiO ₂ , SrO-TiO ₂ , BaO-TiO ₂ , MgO-ZnO, CaO- ZnO, SrO-ZnO, BaO-ZnO, or combinations thereof.

For example, the metal-organic framework may include Zr-based MOFs, Mg-based MOFs, Ca-based MOFs, Sr-based MOFs, Ba-based MOFs, or combinations thereof.

For example, hydrotalcite is [Mg ₄ Al ₂ (OH) ₁₂ (CO ₃ )·4H ₂ O], [Mg ₆ Al ₂ (OH) ₁₆ (CO ₃ )·4H ₂ O], [Mg ₄ Zn ₂ Al ₂ (OH) ₁₆ (CO ₃ ) 4H ₂ O], [Ca ₄ Al ₂ (OH) ₁₂ (NO ₃ ) ₂ xH ₂ O], [Ca ₆ Al ₂ (OH) ₁₆ (NO ₃ ) ₂ ·xH ₂ O], [Ca ₄ Zn ₂ Al ₂ (OH) ₁₆ (CO ₃ )·4H ₂ O], or a combination thereof.

The amount of the heterogeneous catalyst used may be, for example, 600 moles or less, or 50 to 600 moles based on the active metal in the catalyst, based on 1 mole of the hydroxyl furfural compound.

The solid base may include MgO, CaO, CaCO ₃ , hydrotalcite, or mixtures thereof. The solid base acts as a chelate to dissolve the furandicarboxylic acid-based compound in water in the form of a salt. Accordingly, the pH of the oxidation reaction product does not change.

The solid base may be included in an amount of 10 parts by weight to 40 parts by weight, for example, 15 parts by weight to 35 parts by weight, based on 100 parts by weight of the hydroxyl furfural compound. If the content of the solid base is less than 10 parts by weight, the furandicarboxylic acid compound may be precipitated while the oxidation reaction proceeds, and if it exceeds 40 parts by weight, an excessive amount of HCl aqueous solution is used in the crystallization step of the furandicarboxylic acid compound As a result, environmental pollution and excessive wastewater may occur, which may increase manufacturing costs.

During synthesis, the internal pH may be 6 to 8. When proceeding within this pH range, furandicarboxylic acid-based compounds are produced and not precipitated. Precipitation of furandicarboxylic acid-based compounds is not a major problem in batch reactors, but precipitation of furandicarboxylic acid-based compounds inside a continuous tubular reactor may cause clogging of nozzles connecting the tubular reactors.

The oxidizing agent may include oxygen, air, or mixtures thereof.

The solvent may include water, acetonitrile, acetone, dimethylformamide, dimethyl sulfoxide, ethanol, methanol, t-butyl hypochlorite, or mixtures thereof; for example, when water is used, oxygen is better absorbed. can dissolve.

The solvent may be included in an amount of 1000 parts by weight to 9000 parts by weight based on 100 parts by weight of the hydroxyl furfural compound. If the content of the solvent is less than 1000 parts by weight, the dissolution of the hydroxyl furfural compound is not sufficient, so that the oxidation reaction may not be initiated or the oxidizing agent injected may not be sufficiently dissolved, and if the content exceeds 9000 parts by weight, the concentration of the hydroxyl furfural compound As the concentration of the reactants decreases due to the drop, there may be economic losses in the entire process.

The temperature of the oxidation reaction may be 80 °C to 200 °C, for example 100 °C to 180 °C. If the oxidation reaction temperature is less than 80 °C, the reaction may not be initiated, and if it exceeds 200 °C, self-polymerization of the hydroxyl furfural compound may occur and side reactions may proceed.

The pressure of the oxidation reaction may be 6 bar to 50 bar, for example 8 bar to 30 bar. If the oxidation reaction pressure is less than 6 bar, the yield may decrease because sufficient oxygen for generating the furandicarboxylic acid compound is not supplied, and if it exceeds 30 bar, the internal temperature may increase and side reactions may proceed.

The oxidation reaction may be performed for 1 hour to 24 hours, for example 1 hour to 12 hours. If the oxidation reaction time is less than 1 hour, there may be no reaction, and if it exceeds 24 hours, a side reaction may proceed and humin may be produced.

A reaction product obtained through the oxidation reaction step may be a crude composition containing a hydroxyl furfural compound and a furandicarboxylic acid-based compound.

For example, a target compound as a furandicarboxylic acid-based compound may be 2,5-furandicarboxylic acid (FDCA) represented by Formula 6 below.

[Formula 6]

At this time, the reaction product may inevitably include a hydroxyl furfural compound represented by Chemical Formula 1 (eg, compounds represented by Chemical Formulas 2 to 4).

That is, the reaction is an oxidation reaction in the presence of a heterogeneous catalyst using the above-mentioned raw materials, and an oxide of an aromatic heterocyclic compound (hereinafter referred to as a furandicarboxylic acid compound or reaction product) obtained from these reactions is oxidized to an unsaturated group included in the backbone. As shown in Scheme 1, it mainly includes 2,5-furandicarboxylic acid (FDCA), but the reaction intermediates 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) and 5-formylfurancar boxylic acid (FFCA) and the like.

In addition, tetrahydrofuran-2,5-dicarboxylic acid (THFDCA) generated in the process of purifying 5-hydroxymethyl-2-furancarboxylic acid (HMFCA) and 5-formylfurancarboxylic acid (FFCA) ) may be included.

Since these by-products generally have a higher melting point than hydroxyl furfural compounds, they are difficult to remove from the reactor in a molten state and require post-processing such as purification or crystallization.

Accordingly, a purification step of selectively contacting the product of the oxidation reaction with hydrogen in the presence of a heterogeneous reduction catalyst and a solvent to remove 5-formylfurancarboxylic acid may be further included. For example, 5-formylfurancarboxylic acid dissolves the reaction product in a solvent, and 5-formylfurancarboxylic acid breaks the double bond of the furan ring through a hydrogenation reaction (hydrogenation reaction) to water as a solvent. It is dissolved and removed, and a furandicarboxylic acid-based compound that is insoluble in water can be obtained.

The heterogeneous reduction catalyst used in the purification step may include an active metal and a carrier supporting the active metal.

The active metal of the heterogeneous reduction catalyst may include Cu, Ni, Co, Pd, Pt, Ru, Ag, Au, Rh, Os, Ir, alloys thereof, or mixtures thereof.

The carrier may include metal oxides, carbonaceous materials, metal silicates, metal carbides, or mixtures thereof. The metal oxide may include, for example, silica, zirconia, alumina, or mixtures thereof. The carbonaceous material may be, for example, carbon black.

The amount of the heterogeneous reduction catalyst used may be, for example, 50 to 300 moles based on the active metal in the heterogeneous reduction catalyst relative to 1 mole of the product of the oxidation reaction.

The solvent may include water, acetonitrile, acetone, dimethylformamide, dimethyl sulfoxide, ethanol, methanol, t-butyl hypochlorite, or mixtures thereof. For example, when water is used, oxygen in the solvent Oxidation reaction may be easy due to the large dissolved amount.

The amount of the solvent may be 1000 parts by weight to 9000 parts by weight, for example 2000 parts by weight to 8000 parts by weight, based on 100 parts by weight of the product of the oxidation reaction. If the content of the solvent is less than 1000 parts by weight, the reaction may not be initiated, and if it exceeds 9000 parts by weight, economic feasibility may be reduced.

The temperature of the purification reaction may be 100 °C to 200 °C, for example, 100 °C to 180 °C. When the purification reaction temperature is less than 100 ° C., the reaction may not be initiated, and when it exceeds 200 ° C., side reactions may proceed.

The pressure of the purification reaction may be 5 bar to 15 bar, for example 6 bar to 13 bar. When the purification reaction pressure is less than 5 bar, the double bond may not be broken due to lack of hydrogen, and when it exceeds 15 bar, a side reaction may proceed due to an increase in internal temperature.

The purification reaction may be performed for 1 hour to 10 hours, for example, 1 hour to 6 hours. If the purification reaction time is less than 1 hour, 5-formylfurancarboxylic acid may not be sufficiently converted to hydroxymethylfurancarboxylic acid, and if it exceeds 10 hours, a side reaction may proceed.

Optionally, a metal purification step of removing metal components from the oxidation reaction product may be further included. As a heterogeneous catalyst is used in the oxidation reaction step, the furandicarboxylic acid-based compound may contain a metal component, which may cause discoloration of polyester.

The metal component is Fe, Cr, Ni, Cu, Zn, Mo, Ti, Cd, Co, Mn, Na, Mg, K, Ca, Al, As, Sb, Pb, Sn, B, Si, or mixtures thereof. can include In particular, the metal component may be a transition metal including Fe, Cr, Ni, Cu, Zn, Mo, Ti, Cd, Co, Mn, or mixtures thereof. Transition metals affect discoloration during polymer polymerization. In addition, transition metals are converted into metal oxides when heat is applied, and metal oxides have a unique color. For example, Fe easily changes to Fe ₂ O ₃ (Iron(III) oxide) when heated, which has a dark brown color. Therefore, discoloration of polyester can be prevented by removing the metal component from the furandicarboxylic acid compound.

For example, the metal purification step may be performed using an ion filter method. The ion filter has a metal content of less than 200 ppm at room temperature, for example, less than 190 ppm, less than 180 ppm, less than 170 ppm, less than 160 ppm, less than 150 ppm, less than 140 ppm, less than 130 ppm, less than 120 ppm, 110 ppm Less than 100 ppm, less than 90 ppm, less than 80 ppm, less than 70 ppm, less than 60 ppm, less than 50 ppm, less than 40 ppm, less than 30 ppm, less than 20 ppm, less than 10 ppm, less than 9 ppm, less than 7 ppm, Less than 5 ppm, less than 3 ppm, less than 1 ppm, less than 0.9 ppm, less than 0.8 ppm, less than 0.7 ppm, less than 0.6 ppm, less than 0.5 ppm, less than 0.4 ppm, less than 0.3 ppm, less than 0.2 ppm, less than 0.1 ppm, 0.09 ppm below, below 0.08 ppm, or below 0.073 ppm. If the content of the metal component is 200 ppm or more, discoloration may be caused during the polymerization of the polymer, thereby increasing the b* value of the polyester chip.

Thereafter, the reaction product is titrated with an acid such as HCl, washed with water (DIW), and recrystallized to obtain a purified furandicarboxylic acid-based compound.

A furandicarboxylic acid-based compound according to another embodiment is prepared according to the method for preparing a furandicarboxylic acid-based compound described above.

As the furandicarboxylic acid-based compound production method further includes a metal purification step, the furandicarboxylic acid-based compound has a metal component, particularly a transition metal component, with respect to the total weight of less than 200 ppm, for example, 190 ppm, 180 ppm Less than 170 ppm, less than 160 ppm, less than 150 ppm, less than 140 ppm, less than 130 ppm, less than 120 ppm, less than 110 ppm, less than 100 ppm, less than 90 ppm, less than 80 ppm, less than 70 ppm, less than 60 ppm, Less than 50 ppm, less than 40 ppm, less than 30 ppm, less than 20 ppm, less than 10 ppm, less than 9 ppm, less than 7 ppm, less than 5 ppm, less than 3 ppm, less than 1 ppm, less than 0.9 ppm, less than 0.8 ppm, 0.7 ppm less than 0.6 ppm, less than 0.5 ppm, less than 0.4 ppm, less than 0.3 ppm, less than 0.2 ppm, less than 0.1 ppm, less than 0.09 ppm, less than 0.08 ppm, or less than 0.073 ppm, and may be greater than or equal to 0 ppm. When the furan dicarboxylic acid-based compound contains 200 ppm or more of a metal component with respect to the total weight, discoloration may occur during polymerization of the polymer, thereby increasing the b* value of the polyester chip.

In addition, as the furandicarboxylic acid-based compound manufacturing method further includes the step of removing humin, the furandicarboxylic acid-based compound contains 3% by weight or less of humin, for example, 1% by weight based on the total weight. to 3% by weight. When the furandicarboxylic acid-based compound contains more than 3% by weight of humin with respect to the total weight, the b* value of the furandicarboxylic acid-based compound increases, which acts as a major factor in discoloration during polymerization.

In addition, as the furandicarboxylic acid-based compound manufacturing method further includes a purification step, the furandicarboxylic acid-based compound is 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid based on the total weight (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or mixtures thereof in an amount less than 10% by weight. Furandicarboxylic acid-based compounds are 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), Alternatively, when a mixture thereof is included in an amount of 10% by weight or more, the molecular weight of the polymer does not rise to a target value, so that chipping may not occur afterwards.

A method for producing polyester according to another embodiment includes preparing polyester by esterifying a furandicarboxylic acid-based compound and a diol-based compound, followed by polymerization.

In the esterification step, an oligomer is prepared by reacting an aromatic dicarboxylic acid compound including a furan dicarboxylic acid compound and a diol compound.

The aromatic dicarboxylic acid-based compound may further include an additional aromatic dicarboxylic acid, an aliphatic dicarboxylic acid, or a mixture thereof in addition to the furan dicarboxylic acid-based compound.

The aromatic dicarboxylic acid may be an aromatic dicarboxylic acid having 8 to 20 carbon atoms, for example, an aromatic dicarboxylic acid having 8 to 14 carbon atoms or a mixture thereof, and naphthalenedicarboxylic acids such as isophthalic acid, terephthalic acid, and 2,6-naphthalenedicarboxylic acid. boxylic acid, diphenyl dicarboxylic acid, 4,4'-stilbendicarboxylic acid, 2,5-furandicarboxylic acid, or 2,5-thiophenedicarboxylic acid and the like. Terephthalic acid is obtained by dicarboxylic acids such as terephthalic acid, alkyl esters thereof (lower alkyl esters having 1 to 4 carbon atoms such as monomethyl, monoethyl, dimethyl, diethyl or dibutyl esters) and/or acid anhydrides thereof. It may react with a diol component to form a dicarboxylic acid moiety such as a terephthaloyl moiety.

Aliphatic dicarboxylic acids include malonic acid, succinic acid, glutaric acid, 2-methylglutaric acid, 3-methylglutaric acid, adipic acid, pimelic acid, suberic acid, azelaic acid, sebacic acid, undecanedioic acid, dodecane candiic acid, brassylic acid, tetradecanedioic acid, fumaric acid, 2,2-dimethylglutaric acid, suberic acid, maleic acid, itaconic acid, or maleic acid, and the like. In particular, the aliphatic dicarboxylic acid-based compound may be succinic acid or adipic acid.

The diol-based compound may be, for example, an aliphatic diol. Aliphatic diols can impart good compatibility and elongation properties to polyesters.

For example, aliphatic diols include ethylene glycol, diethylene glycol, triethylene glycol, propanediol (1,2-propanediol, 1,3-propanediol, etc.), 1,4-butanediol, pentanediol, hexanediol (1 ,6-hexanediol, etc.), neopentyl glycol (2,2-dimethyl-1,3-propanediol), 1,2-cyclohexanediol, 1,4-cyclohexanediol, 1,2-cyclohexanedimethanol , linear, branched, or cyclic aliphatic diol components such as 1,3-cyclohexanedimethanol, 1,4-cyclohexanedimethanol, and tetramethylcyclobutanediol.

In consideration of the amount of substances lost or unreacted during the esterification reaction, the diol-based compound may be used in excess of the desired copolymer composition.

For example, in the esterification reaction step, 10 to 50 parts by mole of the diol compound may be reacted based on 10 parts by mole of the dicarboxylic acid compound, for example, 12 parts to 45 parts by mole, 14 parts to 40 parts by mole, 16 to 35 parts by mole, or 18 to 30 parts by mole may be reacted. If the diol-based compound is used in an amount greater than 50 parts by mole, the esterification reaction rate may be lowered or the physical properties and productivity of the final polyester may be lowered. On the other hand, when the diol-based compound is used in an amount of less than 10 parts by mole, an excessive amount of unreacted components of the dicarboxylic acid-based compound remains, making it impossible to accurately determine the end point of the esterification reaction. Accordingly, the esterification reaction proceeds for a long time, causing heat discoloration of the final polyester or deteriorating physical properties and brightness of the final polyester.

The esterification reaction step may be performed in a nitrogen (N ₂ ) atmosphere at a temperature range of 160 °C to 260 °C for 1 hour to 8 hours. The esterification reaction step may be appropriately adjusted depending on the mixing ratio of raw materials, the specific characteristics of the desired polyester, and the like. For example, the esterification step may be independently carried out at a temperature range of 180 °C or higher, 160 °C or higher, 170 °C or higher, or 180 °C or higher, and 260 °C or lower, 240 °C or lower, or 220 °C or lower. there is. In addition, the esterification step may be independently performed for 1 hour, 1.5 hours, or 2 hours, and 8 hours, 7 hours, or 6 hours, respectively.

If each temperature, pressure, reaction time, etc. of the esterification reaction step is less than each range, the reaction yield may be low or sufficient reaction may not occur, resulting in deterioration in physical properties of the polyester finally produced. If the temperature, pressure, reaction time, etc. of the esterification reaction exceed each range, the possibility of yellowing the appearance of the polyester produced may increase or the polyester may not be synthesized in the manufacturing method due to the progress of the depolymerization reaction. there is.

Each esterification reaction step can be carried out independently, batchwise or continuously.

Meanwhile, each esterification reaction step may be independently performed in the presence of an esterification reaction catalyst. In particular, the esterification reaction catalyst can be introduced into the esterification reaction step to improve the reaction rate from the beginning of the reaction and shorten the time the polyester is exposed to heat.

For example, the esterification reaction catalyst may be a titanium-based catalyst such as titanium oxide, titanium butoxide, or titanium alkoxide.

The esterification reaction catalyst may be used in an amount of 10 ppm to 1000 ppm based on the central metal atom in the synthesized polyester. If the content of the esterification reaction catalyst is too small, it may be difficult to significantly improve the efficiency of the esterification reaction, and the amount of reactants not participating in the reaction may greatly increase. In addition, if the content of the esterification reaction catalyst is too large, the appearance properties of the polyester produced may be deteriorated. In addition, if the content of the esterification reaction catalyst is too large, yellowing and physical properties of the produced polyester may be deteriorated.

In the polymerization step, the oligomer prepared in the esterification step is polymerized. For example, the polymerization step may include a pre-polymerization step of pre-polymerizing the oligomer and a polycondensation step of performing a polycondensation reaction on the pre-polymerized polymer.

In the prepolymerization step, the oligomer is prepolymerized to prepare a polymer having a higher degree of polymerization than the esterification reaction product.

A polymerization step comprising a pre-polymerization step, a polycondensation step, or both may be performed in the presence of a catalyst.

The polymerization reaction catalyst may be used in an amount of 2 ppm to 100 ppm based on the central metal atom in the synthesized polyester. If the content of the polymerization reaction catalyst is too small, the amount of reactants that do not participate in the reaction may greatly increase, and if the content of the polymerization reaction catalyst is too large, it may remain as inactive particles and deteriorate physical properties of the polymer.

Meanwhile, in the prepolymerization process, a heat stabilizer may be used, and if this is used, heat discoloration during the prepolymerization process and subsequent polycondensation reaction may be minimized.

Specifically, the heat stabilizer is trimethyl phosphonoacetate, triethyl phosphonoacetate, phosphoric acid, phosphorous acid, polyphosphric acid, trimethyl phosphate phosphate: TMP), triethyl phosphate (triethyl phosphate), trimethyl phosphine (trimethyl phosphine), triphenyl phosphine (triphenyl phosphine) may include at least one selected from the group of phosphorus-based heat stabilizers.

For example, the thermal stabilizer may be added in an amount about twice that of the esterification reaction catalyst. Thermal discoloration during prepolymerization and polycondensation reactions can be minimized by using a range of thermal stabilizers.

Pre-polymerization may be performed under temperature controlled conditions (thermal pre-condensation).

Specifically, the pre-polymerization may include raising the temperature until reaching a temperature range of 220° C. to 260° C., and pre-polymerizing the second esterification reaction product while maintaining the temperature.

In addition, after the pressure is reduced until the pressure reaches 0 atm to 0.3 atm when the temperature is raised, the reached pressure may also be maintained when the reached temperature is maintained.

The pre-polymerization step is a step of changing from normal pressure to vacuum before going to a polycondensation reaction (Vacuum), which will be described later, and may be a step of changing from normal pressure (1 atm) to vacuum (0 atm) step by step. If the prepolymerization step is omitted, the esterification reaction product volatilizes in the process of rapidly changing to a vacuum state, causing a Dolby phenomenon, reducing the yield of the final polyester, and adversely affecting its physical properties.

After the prepolymerization, the prepolymerized polymer is subjected to a polycondensation reaction.

The poly-condensation step may be performed for 2 to 6 hours under a vacuum atmosphere, a temperature range of 220 °C to 300 °C, and a pressure of 0.8 torr to 0.4 torr or less.

The polycondensation reaction step may proceed in a vacuum degree higher than 0 atm. The degree of vacuum is measured with a vacuum gauge, and polymerization is usually performed in the range of 0.8 torr to 0.4 torr.

In the case of polycondensation, a polycondensation reaction catalyst may be used.

The polycondensation catalyst may be added to the product of the esterification reaction before starting the polycondensation reaction, may be added to the mixture containing the diol component and the dicarboxylic acid component before the esterification reaction, and may be added during the esterification reaction step. may be

The polymerization reaction catalyst and the polycondensation catalyst may each independently use a titanium-based compound, a germanium-based compound, an antimony-based compound, an aluminum-based compound, a tin-based compound, or a mixture thereof.

As the titanium compound, tetraethyl titanate, acetyltripropyl titanate, tetrapropyl titanate, tetrabutyl titanate, polybutyl titanate, 2-ethylhexyl titanate, octylene glycol titanate, lactate titanate, triethanolamine titanate, acetylacetonate titanate, ethyl acetoacetic ester titanate, isostearyl titanate, titanium dioxide, titanium dioxide/silicone dioxide copolymer, titanium dioxide/zirconium dioxide copolymer and the like.

Germanium-based compounds include germanium dioxide (GeO2), germanium tetrachloride (GeCl ₄ ), germanium ethyleneglycoxide, germanium acetate, copolymers using these, and mixtures thereof. etc. can be mentioned.

According to another embodiment, a polyester including a repeating unit represented by Chemical Formula 7 is provided.

[Formula 7]

In Formula 7, A ¹¹ is each independently a linear or branched divalent aliphatic hydrocarbon group having 1 to 15 carbon atoms, R ¹¹ is a halogen group, a hydroxyl group, an alkoxy group, or an alkyl group, and n ¹¹ is a repetition of each repeating unit. number of times, and n ¹² is an integer from 0 to 2.

For example, n ¹¹ may be appropriately adjusted according to the molecular weight of polyester, and for example, n ¹¹ may each independently be an integer of 1 to 20.

On the other hand, the polyester contains less than 200 ppm of metal components, particularly transition metal components, for example 190 ppm, less than 180 ppm, less than 170 ppm, less than 160 ppm, less than 150 ppm, less than 140 ppm, less than 130 ppm, relative to the total weight. , less than 120 ppm, less than 110 ppm, less than 100 ppm, less than 90 ppm, less than 80 ppm, less than 70 ppm, less than 60 ppm, less than 50 ppm, less than 40 ppm, less than 30 ppm, less than 20 ppm, less than 10 ppm, 9 Less than ppm, less than 7 ppm, less than 5 ppm, less than 3 ppm, less than 1 ppm, less than 0.9 ppm, less than 0.8 ppm, less than 0.7 ppm, less than 0.6 ppm, less than 0.5 ppm, less than 0.4 ppm, less than 0.3 ppm, less than 0.2 ppm , less than 0.1 ppm, less than 0.09 ppm, less than 0.08 ppm, or less than 0.073 ppm, and may include more than 0 ppm. If the polyester contains 200 ppm or more of the metal component with respect to the total weight, discoloration may occur during polymerization of the polymer, thereby increasing the b* value of the polyester chip.

In addition, the polyester may include humin in an amount of 3% by weight or less, for example, 1% to 3% by weight based on the total weight. When the polyester contains more than 3% by weight of humin based on the total weight, the b* value of the polyester chip may increase.

In addition, the polyester is 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or these may contain less than 10% by weight of a mixture of The polyester is 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or mixtures thereof, by weight If it contains 10% by weight or more, the molecular weight of the polymer does not rise to the target value, so chipping may not be performed afterwards.

Polyesters have a number average molecular weight (Mn) of 25,000 g/mol to 65,000 g/mol, such as 30,000 g/mol to 63,000 g/mol, 35,000 g/mol to 61,000 g/mol, 38,000 g/mol to 60,000 g/mol, or from 40,000 g/mol to 58,000 g/mol.

If the polyester has a number average molecular weight of less than 25,000 g/mol, it is difficult to process the polyester into a film for use as a packaging material, and a desired modulus may not be achieved. On the other hand, if it exceeds 65,000 g/mol, the viscosity may increase and productivity and yield may decrease.

Polyester, the ratio of weight average molecular weight (Mw) / number average molecular weight (Mn), that is, molecular weight distribution (Molecular weight distribution, MWD) is 1.1 to 3.0, for example, 1.4 to 2.7, 1.6 to 2.5, or 1.79 to 2.4 can be

When the molecular weight distribution of polyester is less than 1.1, it is difficult to control the process, resulting in high defect rates and high process costs. On the other hand, when the molecular weight distribution of polyester exceeds 3.0, defects may be caused during product manufacturing due to the non-uniform molecular weight distribution.

Polyester may have an L* value of 93 or more, an a* value of -0.5 to 0, and a b* value of 14 or less according to the CIE1976 L*a*b* color system, for example, CIE1976 L*a* The L* value according to the b* color system may be 100 or more, the a* value may be -0.5 to 0, and the b* value may be 7 or less, 5 or less, 3 or less, 1 or less, or 0 to -1.

For example, the measurement method of the polyester color difference meter is as follows. Dissolve 2 g of polyester sample in 20 ml of Hexafluoroisopropanol (HFIP) (0.1 g/ml in HFIP). Konica Minolta's CM-3700A measures the color difference of the sample solution in the Tuartz cell dedicated to the solution color difference measurement.

As the L* value has a higher value, a color closer to white may be displayed. However, depending on the use and purpose of the product to which polyester is applied, the L* value is within the range of 93 or more, 93.5 or more, 94 or more, or 94.5 or more, and 100 or less, 99 or less, 98 or less, 97 or less, or 96 or less. In , you can control the brightness.

In the case of the a* value, as the value decreases in the range of 0 or less, red may become lighter and green may become deeper. However, depending on the use and purpose of the product to which polyester is applied, the a* value is 0 or less, -0.03 or less, -0.06 or less, or -0.1 or less, and -0.5 or more, -0.52 or more, -0.54 or more, or -0.56 Within the above range, the degree of red and green can be controlled.

In the case of the b* value, as the value decreases in the range of 14 or less, yellow may become lighter and blue may become deeper. In particular, according to test examples to be described later, all examples have a b* value of 14 or less, and it can be seen that thermal discoloration such as yellowing and browning during the manufacturing process is suppressed. However, depending on the use and purpose of the product to which polyester is applied, the degree of yellow and blue can be controlled within the range of b* value of 14 or less.

The polyester may have an intrinsic viscosity at 25° C. of 0.6 dl/g to 2.0 dl/g, such as 0.7 dl/g to 1.08 dl/g.

Further, the polyester may have an intrinsic viscosity at 35° C. of 0.4 dl/g to 1.6 dl/g, for example 0.6 dl/g to 0.7 dl/g.

For example, polyester may have a glass transition temperature (Tg) of -40 °C to 50 °C.

Hereinafter, specific embodiments of the invention are presented. However, the embodiments described below are only intended to specifically illustrate or explain the invention, and the scope of the invention should not be limited thereto.

[Preparation Example 1: Preparation of 2,5-furandicarboxylic acid (FDCA)]

(Example 1)

Chloromethylfurfural (CMF) is mixed with water (H ₂ O) and reacted at about 85° C. for 3 minutes to convert to 5-hydroxymethylfurfural. Extract 5-hydroxymethylfurfural (HMF) using ethyl acetate (EA). Ethyl acetate is volatilized and removed with a rotary evaporator while reducing the pressure at room temperature, and 5-hydroxymethylfurfural having a solid content of 100% is prepared.

A Ru/C catalyst, solid base MgO, was charged into a continuous reactor, and 5-hydroxymethylfurfural was oxidized at 30 bar, 140 °C (WHSV = 0.3 h ^-1 ) while supplying solvent H ₂ O and air to obtain 2 ,5-Furandicarboxylic acid (FDCA) is obtained in about 97% yield. At this time, it is confirmed that the pH change is maintained at 7. This means that the solid base MgO dissolves 2,5-furandicarboxylic acid in the form of a salt in water.

After completion of the oxidation reaction, 2,5-furandicarboxylic acid is crystallized by titration with an aqueous HCl solution to obtain 2,5-furandicarboxylic acid in powder form.

Meanwhile, 2,5-furandicarboxylic acid is reacted in an autoclave at 150 °C and 9 bar H ₂ for 3 hours to remove 5-formylfurancarboxylic acid and hydroxymethylfurancarboxylic acid, Tetrahydrofuran-2,5-dicarboxylic acid generated at this time is purified, and metal components are removed using an ion filter.

(Comparative Example 1)

Example 1 was carried out in the same manner as in Example 1, except that the purification process for removing 5-formylfurancarboxylic acid and hydroxymethylfurancarboxylic acid and the purification process for removing metal components were not performed. 5-furandicarboxylic acid is prepared.

(Comparative Example 2)

2,5-furandicarboxylic acid was prepared in the same manner as in Example 1, except that in Example 1, only hydroxymethylfurancarboxylic acid was removed and the purification process to remove the metal component was not performed.

(Comparative Example 3)

In Example 1, 5-formylfurancarboxylic acid and hydroxymethylfurancarboxylic acid were removed, but tetrahydrofuran generated in the process of removing 5-formylfurancarboxylic acid and hydroxymethylfurancarboxylic acid 2,5-furandicarboxylic acid was prepared in the same manner as in Example 1, except that the 2,5-dicarboxylic acid was not removed and the metal component was not purified.

(Comparative Example 4)

2,5-furandicarboxylic acid was prepared in the same manner as in Example 1, except that the metal component was not removed.

[Experimental Example 1: Component analysis of 2,5-furandicarboxylic acid]

2,5-furandicarboxylic acid prepared in Examples and Comparative Examples was analyzed for components using high-performance liquid chromatography (HPLC), and the results are shown in FIGS. 1 to 5, respectively.

In addition, the content of the metal component of the 2,5-furandicarboxylic acid prepared in Examples and Comparative Examples was measured by inductively coupled plasma spectrometry (icp-oes), and the results are summarized in Table 1.

In the inductively coupled plasma spectroscopy method, a liquid sample is introduced into plasma, and when light is emitted from a monochromator/polychromator, the detector is focused and the induced signal is processed to quantify the elemental composition.

metal components
(unit: ppm) λ Comparative Example 1 Example 1 Comparative Example 2 Comparative Example 4 Na 588.9 129.9 33.364 112.53 100.2 Ca 393.2 20 20 3.2 25.132 K 766.4 N.D. N.D. 32 38.222 Mg 279.5 60.2 22.5 55.5 45.5 Fe 238.204 0.482 0.073 13.57 1.67 Mn 257.61 N.D. N.D. 0.174 N.D. Co 228.616 N.D. N.D. N.D. N.D. Cr 267.716 N.D. N.D. N.D. N.D. Ni 221.647 N.D. N.D. N.D. N.D. Cu 324.754 N.D. N.D. N.D. N.D. Mo 202.03 N.D. N.D. N.D. N.D. Pb 246.9 N.D. N.D. N.D. N.D. Ti 323.452 N.D. N.D. 10 N.D. CD 226.502 N.D. N.D. N.D. N.D. Zn 213.856 N.D. N.D. 5 N.D. Sum - 210.582 75.937 231.974 210.724

1 is an HPLC result after FDCA purification, and FIGS. 2 to 5 are HPLC results in which a FFCA peak exists before FDCA purification. 1 to 5, the highest peak on the left side represents FDCA, and a small peak on the right side represents FFCA. When FFCA is included in an amount of 3% or more, it acts as an end capping during polyester polymerization, preventing the molecular weight from increasing, and acting as a major factor in discoloration.

[Production Example 2: Production of Polyester]

After adding 0.9 mol of 2,5-furandicarboxylic acid and 1.2 mol of ethylene glycol (EG) to a hopper of a 10 L autoclave reactor, a Ti-based catalyst (material name: Titanium isopropoxide) was added at 50 ppm based on Ti-based metal. was added, and an esterification reaction was conducted for 3 hours in a temperature range of 210 °C and a 2.5 bar nitrogen atmosphere.

After completion of the esterification reaction, the temperature inside the reactor was raised to a temperature range of 240 ° C. for 1 hour, and then the pressure was gradually reduced using a vacuum pump for 1 hour to reduce the pressure inside the reactor to 0.7 Torr or less, Drain when the load transmitted to the torque meter of the autoclave reaches 80% Torque to obtain polyester.

[Experimental Example 2: Analysis of polyester]

Table 2 summarizes the gel permeation chromatography (GPC) measurement results for the polyester prepared using 2,5-furandicarboxylic acid in Example 1 and Comparative Example 1.

Mn Mw Mz PDI Comparative Example 1 16160 37853 72364 2.3423 Example 1 20678 37574 54835 1.8171

Referring to Table 2, the polyester prepared using 2,5-furandicarboxylic acid of Comparative Example 1 in which 5-formylfurancarboxylic acid, etc. was not purified had a PDI (=Mw/Mn) of about 2.34 And, it can be seen that the polyester prepared using 2,5-furandicarboxylic acid of Example 1 in which 5-formylfurancarboxylic acid is purified has PDI (=Mw/Mn) reduced to about 1.81. there is.

In addition, in the case of polyester prepared using 2,5-furandicarboxylic acid of Example 1, the low molecular peak is reduced, Mn is shifted to high molecular weight, and the overall PDI is narrowed, resulting in a more monodisperse It can be seen that a (monodisperse) polymer was obtained.

In addition, with respect to the polyester prepared using 2,5-furandicarboxylic acid prepared in Example 1, Comparative Example 1, and Comparative Example 4, FFCA content, viscosity (IV), and b* values were measured, , and the results are summarized in Table 3.

Comparative Example 1 Comparative Example 4 Example 1 FFCA content (% by weight) 1.68% 0 % 0 % polyester color

polymerization time about 2 hours 30 minutes about 2 hours 30 minutes about 2 hours 30 minutes Viscosity (IV) 0.521 0.533 0.529 b* 25 17 One

Referring to Table 3, it can be seen that there is no discoloration of the polyester when the total transition metal content is 200 ppm or less.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention defined in the following claims are also made according to the present invention. falls within the scope of the rights of

Claims (20)

preparing a hydroxyl furfural compound from a hydroxyl-free furfural compound; and
Preparing a furandicarboxylic acid-based compound by oxidizing the hydroxyl furfural compound in the presence of a heterogeneous catalyst
A method for producing a furandicarboxylic acid-based compound comprising a. In paragraph 1,
The hydroxyl-free furfural compound is chloromethyl furfural (CMF), 2,5-diformylfuran (DFF), 5-acetoxymethylfurfural (AMF) , or a mixture thereof,
The hydroxyl furfural compound includes 5-hydroxymethyl furfural (hydroxymethyl furfural, HMF), 5-hydroxymethylfurfural ester, 5-hydroxymethylfurfural ether, or a furandicar, including mixtures thereof. A method for producing a boxylic acid compound. In paragraph 1,
In the step of preparing the hydroxyl furfural compound, the solution containing the hydroxyl-free furfural compound and the solvent is stirred at 100 rpm to 500 rpm at 20 ° C. to 90 ° C. for 1 minute to 60 minutes. A method for producing a furandicarboxylic acid-based compound by reacting. In paragraph 1,
Method for producing a furandicarboxylic acid-based compound, further comprising adding a solvent to the prepared hydroxyl furfural compound and then filtering to remove humin. In paragraph 1,
The oxidation reaction is formed by contacting a solution containing the hydroxyl furfural compound and a solvent with an oxidizing agent in the presence of a solid base and the heterogeneous catalyst. In paragraph 1,
The heterogeneous catalyst includes Fe, Ni, Ru, Rh, Pd, Os, Ir, Au, Pt, an active metal including an alloy thereof, or a mixture thereof, and a carrier supporting the active metal. A method for producing a carboxylic acid compound. In paragraph 5,
The solid base comprises MgO, CaO, CaCO ₃ , hydrotalcite, or a mixture thereof. In paragraph 5,
The solvent is water, acetonitrile, acetone, dimethylformamide, dimethyl sulfoxide, ethanol, methanol, t-butyl hypochlorite, or a method for producing a furandicarboxylic acid-based compound comprising a mixture thereof. In paragraph 1,
The oxidation reaction is carried out for 1 hour to 24 hours at a pressure of 6 bar to 50 bar and a temperature of 80 ℃ to 200 ℃, a method for producing a furandicarboxylic acid-based compound. In paragraph 1,
The products of the oxidation reaction include 2,5-furandicarboxylic acid (FDCA) and 5-formylfurancarboxylic acid (FFCA),
Method for producing a furandicarboxylic acid-based compound further comprising a purification step of contacting the product of the oxidation reaction with hydrogen in the presence of a heterogeneous reduction catalyst and a solvent to remove the 5-formylfurancarboxylic acid. In paragraph 10,
The purification step is made at 5 bar to 15 bar and 100 ℃ to 200 ℃ for 1 hour to 10 hours, a method for producing a furandicarboxylic acid-based compound. In paragraph 1,
Method for producing a furandicarboxylic acid-based compound further comprising a metal purification step of removing a metal component from the product of the oxidation reaction. In paragraph 12,
The metal component is Fe, Cr, Ni, Cu, Zn, Mo, Ti, Cd, Co, Mn, Na, Mg, K, Ca, Al, As, Sb, Pb, Sn, B, Si, or a mixture thereof. A method for producing a furandicarboxylic acid-based compound comprising a. In paragraph 12,
The metal purification step is made using an ion filter, a method for producing a furandicarboxylic acid-based compound. It is prepared according to the method for producing a furandicarboxylic acid-based compound according to claim 1,
Containing less than 200 ppm of metal components by weight,
Furandicarboxylic acid-based compounds. A method for producing polyester, comprising the step of preparing polyester by esterifying the furandicarboxylic acid-based compound according to claim 15 and the diol-based compound, followed by polymerization. It includes a repeating unit represented by Formula 7 below,
Contains less than 200 ppm of metal components based on the total weight,
A polyester having a b* value of 14 or less according to the CIE1976 L*a*b* colorimeter.
[Formula 7]

In Formula 7,
A ¹¹ is a straight-chain or branched-chain divalent hydrocarbon group having 1 to 15 carbon atoms;
R ¹¹ is a halogen group, a hydroxyl group, an alkoxy group, or an alkyl group;
n ¹¹ is the number of repetitions of the repeating unit;
The n ¹² is an integer of 0 to 2. In paragraph 17,
The polyester comprises 3% by weight or less of humin based on the total weight, polyester. In paragraph 17,
The polyester is 5-formylfurancarboxylic acid (FFCA), hydroxymethylfurancarboxylic acid (HMFCA), tetrahydrofuran-2,5-dicarboxylic acid (THFDCA), or any of these A polyester comprising less than 10% by weight of admixtures. In paragraph 17,
The polyester has an L* value of 93 or more according to the CIE1976 L*a*b* color difference system, an a* value of -0.5 to 0, and a b* value of 14 or less.

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