A kind of 2,5-furandicarboxylic acid granules and its preparation method and application

Abstract

The present invention discloses 2,5-furandicarboxylic acid particles, a preparation method, and applications thereof, belonging to the technical field of preparing bio-based monomers for polymerization reactions. Using 2,5-furandicarboxylic acid as a raw material, the FDCA particles are dissolved in water by high-temperature heating, cooled and filtered, and dried to obtain particles having an almost non-angular appearance, a rounded and smooth particle surface, high sphericity, good fluidity, an average particle size of 50-200 μm, a loose bulk density of 0.7-1.0 g / mL, and an angle of repose of 25-40°. The present invention improves the fluidity of the FDCA slurry by changing the microscopic morphology and particle size distribution of the FDCA solid particles, thereby facilitating the uniformity of the materials in the polymerization process and shortening the polymerization reaction time. Furthermore, the amount of ethylene glycol used can be reduced, thereby reducing the content of the diethylene glycol impurity.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of bio-based monomers through polymerization reaction, and particularly relates to 2,5-furandicarboxylic acid particles, a preparation method and application thereof. Background Art

[0002] 2,5-Furandicarboxylic acid (FDCA) can be produced from biomass raw materials. The usual preparation process is that biomass containing hexose undergoes a dehydration reaction to produce 5-hydroxymethylfurfural (5-HMF), and then 5-HMF is oxidized to produce FDCA. FDCA can replace the petroleum-based monomer terephthalic acid (PTA) to produce high-performance polymers, such as polyethylene 2,5-furandicarboxylate (PEF). This polymer has attracted widespread attention. Compared with polyethylene terephthalate (PET), it has better oxygen and carbon dioxide barrier properties and a lower carbon footprint. Because it comes from biomass, the use of PEF plastics can reduce dependence on petroleum-based polymers.

[0003] Currently, the technology for producing PTA by oxidizing paraxylene (PX) and for producing PET by polymerizing PTA with ethylene glycol is highly mature. Global PTA production capacity has exceeded 95 million tons, and bottle-grade PET production capacity has exceeded 35 million tons. Typically, during the polymerization reaction for producing PET, terephthalic acid (TEA) and ethylene glycol are mixed and added to the reaction system as a slurry. To improve reaction uniformity, a TEA slurry with good fluidity is preferred. This powder fluidity also facilitates handling of the TEA powder, such as transportation and storage. Industrially, to achieve good slurry properties and reaction uniformity, an excess of ethylene glycol relative to the stoichiometric amount of TEA is used. However, excess ethylene glycol can lead to increased impurities and energy consumption during the polycondensation reaction.

[0004] As a substitute for PTA, FDCA also needs to undergo a similar polymerization process. The slurry formed after the FDCA particles are mixed with ethylene glycol needs to ensure good fluidity, which is conducive to the uniformity of the reaction and can shorten the polymerization reaction time. Patent document CN114929679A discloses a process for producing a carboxylic acid composition including 2,5-furandicarboxylic acid. The heat treatment method of this process is to dissolve a certain percentage of FDCA in a treatment solvent composition during the heat treatment, while the remaining FDCA remains as a solid precipitate. The chemical balance and exchange between the dissolved FDCA and the precipitated FDCA during the heat treatment process lead to a particularly favorable particle shape, increased particle strength and / or a beneficial particle size distribution of FDCA. However, the chemical balance and exchange between the dissolved FDCA and the precipitated FDCA are difficult to control, resulting in a low yield of FDCA particles. Patent document CN116120264A discloses a method for regulating the particle size of 2,5-furandicarboxylic acid crystals. The method comprises adding a crystallization aid to the raw material of FDCA, and adjusting the type and content of the aid, combined with the adjustment of process parameters such as crystallization temperature, etc., to obtain FDCA crystals with a certain particle size range. The average particle size of the FDCA crystals is d 50 The particle size is 20-2000 μm. However, this method requires the use of regulating agents, which reduces the purity of the crystals and is more complicated.

[0005] The fluidity of FDCA slurries is affected by the particle size distribution and average particle size of the FDCA particles. Generally speaking, a wide particle size distribution, from large to small, tends to improve the slurry properties of the particles. An average particle size range of 50-150 μm is generally preferred. If the proportion of particles larger than 250 μm (40 mesh) increases, the FDCA can easily react incompletely during direct polymerization, leading to problems such as prolonged reaction time and increased byproducts. Similar to the direct polymerization method for PET, to achieve good slurry properties and reaction uniformity, an excess of ethylene glycol relative to the FDCA stoichiometric amount can be used. However, excessive ethylene glycol can lead to an increase in the impurity diethylene glycol fragments, a decrease in the degree of polymerization, and a darkening of the color. However, using ethylene glycol in an amount close to the FDCA stoichiometric amount can cause the polymerization reaction system to be very viscous, with uneven dispersion of solid particles and increased power consumption required for stirring.

[0006] Based on this, in order to improve the slurry properties during the polymerization reaction, a 2,5-furandicarboxylic acid particle and a preparation method thereof are urgently needed to solve the above problems. Summary of the Invention

[0007] One of the purposes of the present invention is to provide a 2,5-furandicarboxylic acid particle to solve the problem of uneven distribution and poor discreteness of existing FDCA particles;

[0008] The second object of the present invention is to provide a method for preparing 2,5-furandicarboxylic acid particles;

[0009] A third object of the present invention is to provide an application of 2,5-furandicarboxylic acid particles in the synthesis process of polyethylene 2,5-furandicarboxylate (FEF) to solve the problems of poor fluidity and uniformity of the mixed slurry of FDCA and ethylene glycol in the existing preparation process of FEF, resulting in low polymerization reaction efficiency and high content of impurity diethylene glycol.

[0010] The purpose of the present invention can be achieved through the following technical solutions:

[0011] In a first aspect, a 2,5-furandicarboxylic acid particle is characterized by having an average particle size of 50-200 μm, a loose bulk density of 0.7-1.0 g / mL, and an angle of repose of 25-40°.

[0012] In a second aspect, a method for preparing 2,5-furandicarboxylic acid particles comprises the following steps:

[0013] The 2,5-furandicarboxylic acid raw material is added to an autoclave, and deionized water is added to the autoclave to obtain a mixed liquid. Stirring and heating are started to increase the system temperature from room temperature (25-30° C.) to 100-150° C., and then the mixture is kept warm for reaction. After the insulation is completed, the mixture is cooled to room temperature. The material is filtered and collected, and then washed to obtain a wet product of 2,5-furandicarboxylic acid, which is then dried to obtain 2,5-furandicarboxylic acid particles.

[0014] As a further embodiment of the present invention, the purity of the 2,5-furandicarboxylic acid raw material is greater than 95%.

[0015] As a further embodiment of the present invention, the pressure of the system in the autoclave is less than 1.5 MPa.

[0016] As a further solution of the present invention, the mass percentage of 2,5-furandicarboxylic acid in the mixed liquid is 5%-20%.

[0017] As a further embodiment of the present invention, the stirring rate is 200-400 rpm.

[0018] As a further solution of the present invention, the heating time is 2-4 hours.

[0019] As a further solution of the present invention, the insulation time is 0.5-6h.

[0020] As a further solution of the present invention, the cooling time is 2-10 hours.

[0021] In a third aspect, a use of the 2,5-furandicarboxylic acid particles prepared by the above-mentioned 2,5-furandicarboxylic acid particles or the method for preparing 2,5-furandicarboxylic acid particles in a polymerization reaction.

[0022] Compared with the prior art, the present invention has the following beneficial effects:

[0023] 1. The present invention discloses 2,5-furandicarboxylic acid, which has a relatively simple preparation method. The FDCA particles prepared by the preparation method have a microscopic morphology with almost no edges and corners, a round and smooth particle surface, high sphericity, good discreteness, and a high bulk density. The average particle size is 50-200 μm, the loose bulk density is 0.7-1.0 g / mL, and the angle of repose (or angle of repose) is 25-40°.

[0024] 2. The present invention significantly improves the fluidity of the FDCA slurry by changing the appearance and particle size distribution of the FDCA solid particles, which helps to improve the uniformity of the polymerization reaction materials while shortening the polymerization reaction time. In the PEF polymerization process, the use of ethylene glycol equivalent can be reduced, which helps to reduce the content of the impurity diethylene glycol. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The present invention will be further described below with reference to the accompanying drawings.

[0026] Figure 1 This is a microscopic morphology of FDCA particles prepared in Example 1 of the present invention;

[0027] Figure 2 It is a microscopic morphology diagram of the FDCA raw material in the present invention. DETAILED DESCRIPTION

[0028] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0029] A method for preparing 2,5-furandicarboxylic acid particles comprises the following steps:

[0030] A 2,5-furandicarboxylic acid raw material with a purity of greater than 95% is added to an autoclave, and deionized water is added to the autoclave to obtain a mixed liquid, wherein the mass percentage of 2,5-furandicarboxylic acid in the mixed liquid is 5%-20%. Stirring and heating are started at a stirring rate of 200-400 rpm, so that the system temperature is raised from room temperature to 100-150° C. for 2-4 hours, and then the mixture is kept warm for reaction for 0.5-6 hours. During the reaction, the pressure of the system in the autoclave is less than 1.5 MPa. After the insulation is completed, the mixture is cooled to room temperature for 2-10 hours. The material is filtered and collected, and then washed to obtain a wet product of 2,5-furandicarboxylic acid, which is then dried to obtain 2,5-furandicarboxylic acid particles.

[0031] Example 1

[0032] A method for preparing 2,5-furandicarboxylic acid particles comprises the following steps:

[0033] 100 g of 99.5% pure 2,5-furandicarboxylic acid raw material was added to an autoclave, and 400 g of deionized water was added to the autoclave to obtain a mixed liquid. After sealing, stirring and heating were started at a stirring rate of 300 rpm, so that the system temperature rose from room temperature to 145° C., the heating time was 2.5 hours, and the autoclave was kept warm for reaction for 6 hours. During the reaction, the pressure of the system in the autoclave was 1 MPa; after the insulation was completed, the temperature was cooled to room temperature, and the cooling time was 4 hours; the material was filtered and collected, and a small amount of deionized water was rinsed to obtain a wet product of 2,5-furandicarboxylic acid, which was dried to obtain 2,5-furandicarboxylic acid particles.

[0034] Example 2

[0035] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that 1900 g of deionized water is added to the autoclave, and the other components and parameters remain unchanged.

[0036] Example 3

[0037] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that 990 g of deionized water is added to the autoclave, and the other components and parameters remain unchanged.

[0038] Example 4

[0039] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the holding time after heating is 1.5 hours, and the other components and parameters remain unchanged.

[0040] Example 5

[0041] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the holding time after heating is 5.5 hours, and the other components and parameters remain unchanged.

[0042] Example 6

[0043] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the system temperature is increased from room temperature to 110° C. for 2 hours, and the other components and parameters remain unchanged.

[0044] Example 7

[0045] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the system temperature is increased from room temperature to 130° C. for 2 hours, and the other components and parameters remain unchanged.

[0046] Example 8

[0047] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the particles are cooled to room temperature after the insulation is completed, and the cooling time is 1.5 hours. Other components and parameters remain unchanged.

[0048] Example 9

[0049] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the particles are cooled to room temperature after the insulation is completed, and the cooling time is 6 hours. Other components and parameters remain unchanged.

[0050] Example 10

[0051] A method for preparing 2,5-furandicarboxylic acid particles is the same as that in Example 1, except that the particles are cooled to room temperature after the insulation is completed, the cooling time is 9 hours, and the other components and parameters remain unchanged.

[0052] The performance of the 2,5-furandicarboxylic acid particles prepared in Examples 1 to 10 was characterized:

[0053] (1) Microscopic characterization of micromorphology: Figure 1 This is a microscopic morphology of the 2,5-furandicarboxylic acid particles prepared in Example 1. Figure 2 The microscopic morphology of 2,5-furandicarboxylic acid raw material; Figure 1 and Figure 2 By comparison, it can be seen that the appearance of the FDCA particles after the reaction is almost free of edges and corners, the particle surface is round and smooth, the sphericity is high, and the dispersion is good;

[0054] (2) Average particle size: calculated after screening with a standard sieve;

[0055] (3) Bulk density: The bulk density of the particles was determined using the test method specified in GB / T 16913-2008;

[0056] (4) Angle of repose test: The angle of repose of the particles was measured using the test method specified in GB / T 16913-2008;

[0057] The test results are shown in Table 1:

[0058] Table 1

[0059] Implementation Cases Average particle size (μm) Bulk density (g / mL) Angle of Repose Example 1 85μm 0.98g / mL 25° Example 2 195μm 0.80g / mL 38° Example 3 136μm 0.78g / mL 36° Example 4 154μm 0.83g / mL 35° Example 5 110μm 0.99g / mL 28° Example 6 55μm 0.74g / mL 39° Example 7 75μm 0.83g / mL 36° Example 9 84μm 0.98g / mL 30° Example 10 65μm 0.99g / mL 32°

[0060] As can be seen from Table 1, the mass fraction of FDCA in the mixture of FDCA and water, the heating temperature, holding time, and cooling time are all factors that affect the average particle size, bulk density, and repose angle of FDCA particles. Optimizing the reaction conditions can produce FDCA particles of better quality.

[0061] Example 11

[0062] A method for applying 2,5-furandicarboxylic acid particles, using the synthesis of polyethylene furandicarboxylate as a model example of a polymerization reaction, comprises the following steps:

[0063] The 2,5-furandicarboxylic acid particles (15.6 g, 0.1 mol) and ethylene glycol (6.8 g, 0.11 mol) prepared in Example 1 were added to a slurry tank, fully mixed in the slurry tank, and then entered into an esterification tank. The reaction was stopped at 190° C. for 2 h and the water was discharged. 0.78 g of catalyst germanium oxide was added to the dimethyl furandicarboxylate generated in the esterification step, and then melt polycondensation was carried out in a polycondensation kettle. The reaction was stopped at a pressure of 70 Pa and 235° C. for 3 h to obtain a polymer PEF (polyethylene furandicarboxylate).

[0064] Comparative Example 1

[0065] A 99.5% pure 2,5-furandicarboxylic acid raw material (15.6 g, 0.1 mol) and ethylene glycol (6.8 g, 0.11 mol) were added to a slurry tank, mixed thoroughly in the slurry tank, and then entered into an esterification tank. The reaction was stopped at 190° C. for 2 hours and the water was discharged. 0.78 g of catalyst germanium oxide was added to the dimethyl furandicarboxylate generated in the esterification step, and then melt polycondensation was carried out in a polycondensation kettle. The reaction was stopped at a pressure of 70 Pa and 235° C. for 3 hours to obtain a polymer PEF (polyethylene furandicarboxylate).

[0066] The performance tests of the PEF polyesters prepared in Example 11 and Comparative 1 were carried out:

[0067] Diethylene glycol content test: The diethylene glycol content is tested using the methanol transesterification method in GB / T 14190-2017;

[0068] PEF polyester molecular weight test: The polyester molecular weight was determined using gel permeation chromatography (GPC); the test results are shown in Table 2;

[0069] Table 2

[0070] Implementation Cases Diethylene glycol content PEF molecular weight Example 11 1.35％ 31000 Comparative Example 1 1.54％ 18000

[0071] As shown in Table 2, when preparing PEF under the same dosage parameter conditions, optimizing the reaction conditions to obtain high-quality FDCA particles is beneficial to improving the uniformity of the PEF polymerization process materials and shortening the polymerization reaction time. More importantly, it can reduce the equivalent amount of ethylene glycol used, thereby reducing the content of the impurity diethylene glycol.

[0072] It should be noted that, in this document, relational terms such as first and second, etc., are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprises," "includes," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or apparatus.

[0073] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A 2,5-furandicarboxylic acid granule, characterized in that: The average particle size is 50-200 μm, the loose bulk density is 0.7-1.0 g / mL, and the angle of repose is 25-40°; The 2,5-furandicarboxylic acid particles are prepared by the following steps: The 2,5-furandicarboxylic acid raw material is added to an autoclave, and deionized water is added to the autoclave to obtain a mixed liquid. Stirring and heating are started to increase the system temperature from room temperature to 100-150° C., and then the mixture is kept warm for reaction. After the insulation is completed, the mixture is cooled to room temperature. The material is filtered and collected, and then washed to obtain a wet product of 2,5-furandicarboxylic acid, which is then dried to obtain 2,5-furandicarboxylic acid particles.

2. A method for preparing the 2,5-furandicarboxylic acid particles according to claim 1, characterized in that: The following steps are involved: The 2,5-furandicarboxylic acid raw material is added to an autoclave, and deionized water is added to the autoclave to obtain a mixed liquid. Stirring and heating are started to increase the system temperature from room temperature to 100-150° C., and then the mixture is kept warm for reaction. After the insulation is completed, the mixture is cooled to room temperature. The material is filtered and collected, and then washed to obtain a wet product of 2,5-furandicarboxylic acid, which is then dried to obtain 2,5-furandicarboxylic acid particles.

3. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The purity of the 2,5-furandicarboxylic acid raw material is greater than 95%.

4. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The pressure of the system in the autoclave is less than 1.5 MPa.

5. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The mass percentage of 2,5-furandicarboxylic acid in the mixed liquid is 5%-20%.

6. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The stirring rate is 200-400 rpm.

7. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The heating time is 2-4 hours.

8. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The insulation time is 0.5-6h.

9. The method for preparing 2,5-furandicarboxylic acid particles according to claim 2, characterized in that: The cooling time is 2-10 hours.

10. Use of the 2,5-furandicarboxylic acid particles according to claim 1 in a polymerization reaction.

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