Bio-based succinic acid particles as well as preparation method and application thereof

Abstract

The invention provides bio-based succinic acid particles as well as a preparation method and application thereof. The D10 particle size of the bio-based succinic acid particles is 150-300 [mu] m, the D50 particle size of the bio-based succinic acid particles is 300-500 [mu] m, and the D90 particle size of the bio-based succinic acid particles is 500-800 [mu] m. The D10, D50 and D90 particle sizes of the bio-based succinic acid particles are within a specific range, on one hand, the problems of dust raising, inhalation and the like of traditional succinic acid fine powder in application are solved, on the other hand, the moisture absorption rate of the bio-based succinic acid particles is remarkably reduced, the problem of agglomeration and caking in long-term storage is avoided, and the storage performance and downstream application performance are improved; the bio-based succinic acid particles have good processability, and polyester prepared from the bio-based succinic acid particles has excellent mechanical properties.

Description

A bio-based succinic acid particle, its preparation method and application Technical Field

[0001] This invention belongs to the field of organic materials technology, specifically relating to a bio-based succinic acid particle, its preparation method, and its application. Background Technology

[0002] Succinic acid, also known as succinic acid, is an important chemical raw material with a wide range of applications, including food additives, medical and health care, chemical industry, and biodegradable plastics. The industrial preparation methods of succinic acid can be divided into two categories: chemical synthesis and microbial fermentation. Chemical synthesis methods, such as the hydrolysis of succinic acid to obtain succinic acid or the catalytic reaction of butenadic acid to obtain succinic acid, yield products collectively known as petroleum-based succinic acid. Microbial fermentation utilizes renewable biomass resources as raw materials, obtaining bio-based succinic acid through fermentation by succinic acid-producing strains. With the rapid development of biology, bio-based succinic acid obtained through microbial fermentation followed by separation and purification has achieved large-scale commercialization and is expected to replace petroleum-based succinic acid as the mainstream product in the succinic acid market.

[0003] Crystallization is one of the important separation and purification steps in the production of bio-based succinic acid. Currently, most industries use continuous crystallization processes. However, due to the crystal characteristics of succinic acid, the crystallized product particles are usually small, with a median particle size D. 50 Generally less than 150 μm, in downstream applications, smaller powders not only cause serious dust pollution, which is not conducive to feeding and poses an inhalation risk, but also have a high moisture absorption rate during long-term storage. They are easily compressed and agglomerated, resulting in short storage time and deterioration of performance at the application end.

[0004] CN117304019A discloses a method for improving the particle size of succinic acid, comprising the following steps: adding succinic acid solution to a crystallization flask, stirring, and after the crystallization temperature drops to 40-60℃, adding a nonionic surfactant to the crystallization flask, and then increasing the cooling rate to 1-8℃ / h to continue the second-stage crystallization; when the crystallization temperature drops to 5-30℃, continuing stirring for 0.5-3h to carry out the third-stage crystal growth, stopping stirring after completion, and separating the succinic acid crystals from the mother liquor. Adding a surfactant during the crystallization process can improve the particle size of succinic acid crystals; however, the surfactant introduces additional impurities into the crystallization system, affecting the quality and yield of succinic acid crystals, and significantly increasing production costs, which is detrimental to industrial production; more importantly, this type of succinic acid product still suffers from high hygroscopicity and easy agglomeration during long-term storage.

[0005] Therefore, developing a bio-based succinic acid that is not prone to moisture absorption and clumping, has good processing performance, and is beneficial to improving the mechanical properties of downstream products (such as polyester) is an urgent problem to be solved in this field. Summary of the Invention

[0006] To address the shortcomings of existing technologies, the present invention aims to provide a bio-based succinic acid granule, its preparation method, and its application. The bio-based succinic acid granule has a low moisture absorption rate, avoiding the problem of agglomeration and clumping during long-term storage, thus improving storage performance and downstream application performance. Furthermore, the bio-based succinic acid granule has good processing performance, and the polyester prepared from the bio-based succinic acid granule has excellent mechanical properties.

[0007] To achieve this objective, the present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides bio-based succinic acid particles, wherein the bio-based succinic acid particles have a D 10 Particle size is 150-300 μm, D 50 Particle size is 300-500 μm, D 90 The particle size is 500-800 μm.

[0009] The bio-based succinic acid particles provided by this invention have D 10 D 50 D 90 With particle size within a specific range, the problems of dust generation and inhalation associated with traditional succinic acid fine powder in applications are solved; simultaneously, based on specific D... 10 D 50 D 90 This process imparts specific particle size distribution characteristics to the bio-based succinic acid particles, significantly reducing their moisture absorption rate and preventing agglomeration during long-term storage, thereby improving storage performance and downstream application performance. Simultaneously, it ensures good flowability and processing performance of the bio-based succinic acid particles, and also results in good mechanical properties for downstream products such as polyester prepared from the bio-based succinic acid particles.

[0010] In this invention, the D of the bio-based succinic acid particles 10 D 50 D 90 If the particle size is too small, the bio-based succinic acid will have a high hygroscopicity and poor moisture absorption; furthermore, the small particle size makes it prone to agglomeration, which will also affect the mechanical properties of downstream products; D 10 D 50 D 90 Large particle size results in poor processing performance and adverse effects on the synthesis of downstream products (such as polyester): excessively large particle size slows down the dissolution and diffusion rate during melt polycondensation, leading to a reduction in the contact area with the diol, a decrease in the synthesis reaction rate, and thus a wider molecular weight distribution (PDI) of the polyester, which in turn leads to a deterioration in the mechanical properties (such as tensile strength and elongation at break) of the prepared polyester.

[0011] The following are preferred technical solutions of the present invention, but are not intended to limit the technical solutions provided by the present invention. The purpose and beneficial effects of the present invention can be better achieved and realized through the following preferred technical solutions.

[0012] In this invention, the D of the bio-based succinic acid particles 10 The particle size is 150-300 μm, for example, it can be 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 250 μm, 260 μm or 280 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0013] The bio-based succinic acid particles have D 50 The particle size is 300-500 μm, for example, it can be 320 μm, 340 μm, 350 μm, 360 μm, 380 μm, 400 μm, 420 μm, 440 μm, 450 μm, 460 μm or 480 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0014] The bio-based succinic acid particles have D 90 The particle size is 500-800 μm, for example, it can be 520 μm, 550 μm, 580 μm, 600 μm, 620 μm, 650 μm, 680 μm, 700 μm, 720 μm, 750 μm or 780 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0015] In this invention, the term D 10 Particle size, D 50 Particle size, D 90 The particle size represents the particle size corresponding to the cumulative volume distribution percentage of the bio-based succinic acid particles being 10%, 50%, and 90%, respectively.

[0016] For example, D 10 Particle size, D 50 Particle size, D 90 The particle size can be determined by laser particle size analyzer according to the standard GB / T 19077-2016 Particle Size Distribution Laser Diffraction Method.

[0017] Preferably, the purity of the bio-based succinic acid particles is ≥99.5%, for example, it can be 99.55%, 99.6%, 99.65%, 99.68%, 99.7%, 99.72%, 99.75%, 99.78%, 99.8%, 99.82%, 99.85%, 99.88%, or 99.9%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0018] For example, the purity (mass content of succinic acid) of the bio-based succinic acid particles can be tested by the method in GB / T34686-2017.

[0019] Preferably, the crystallinity of the bio-based succinic acid particles is ≥84%, for example, it can be 85%, 86%, 87%, 88%, 89%, 90%, 90.5%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, 99% or 100%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 90-95% is further preferred.

[0020] As a preferred embodiment of the present invention, the bio-based succinic acid particles have a higher degree of crystallinity (≥84%, more preferably ≥90%). In downstream applications, such as when used to prepare polyester, they are more likely to react with diols to form long-range ordered polyester segments, which promotes the regular arrangement and crystallization ability of the polyester main chain, increases the intermolecular forces, and thus improves the tensile properties of the polyester.

[0021] Preferably, the moisture absorption rate of the bio-based succinic acid particles is ≤0.5%, for example, it can be 0.15%, 0.18%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, or 0.48%, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0022] For example, the moisture absorption rate is obtained by testing as follows: take a bio-based succinic acid particle sample with mass m; place the sample in a constant temperature and humidity chamber at 25±1℃ and 65±5% for 24 h, take it out and weigh it to obtain the mass of the sample as m2, and the moisture absorption rate = 100% × (m2-m) / m.

[0023] Preferably, the X-ray powder diffraction pattern of the bio-based succinic acid particles has characteristic peaks at diffraction angles 2θ of 16.3±0.5°, 21.5±0.5°, 24±0.5°, 29.5±0.5° and 34±0.5°.

[0024] In this invention, in the X-ray powder diffraction pattern of the bio-based succinic acid, taking the peak intensity of the characteristic peak at a diffraction angle 2θ of 16.3±0.5° as 100%, the peak intensity of the characteristic peak at a diffraction angle 2θ of 21.5±0.5° is 70~100%, for example, it can be 72%, 75%, 78%, 80%, 82%, 85%, 88%, 90%, 92%, 95%, 98% or 100%, and specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range. The peak intensity of the characteristic peak at a diffraction angle 2θ of 24±0.5° is 60-80%, for example, it can be 62%, 64%, 66%, 68%, 70%, 72%, 74%, 76%, 78%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range. The peak intensity of the characteristic peak at a diffraction angle 2θ of 29.5±0.5° is 50-70%, for example, it can be 52%, 54%, 55%, 56%, 58%, 60%, 62%, 64%, 65%, 66%, or 68%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range. The peak intensity of the characteristic peak at a diffraction angle of 2θ of 34±0.5° is 0.4-3%, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5% or 2.8%, and specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific point values ​​included in the range.

[0025] In this invention, the half-width at half-maximum (WHM) of the bio-based succinic acid is 0.1°~0.19°, more preferably 0.12°~0.15°.

[0026] In this invention, the X-ray powder diffraction pattern was obtained by testing under Cu-Kα radiation, and the measured λ was 1.5406 Å.

[0027] In a second aspect, the present invention provides a method for preparing bio-based succinic acid particles as described in the first aspect, the method comprising the following steps:

[0028] (1) The bio-based succinic acid supersaturated solution is transferred from temperature T 11 Cool to temperature T at a rate of v1 12 Subsequently, through temperature-controlled crystallization and solid-liquid separation, the first crystal was obtained; wherein, T 11 ≥78℃, T 12 ≤20℃, v1≤1℃ / min;

[0029] (2) The first crystal is mixed with a solvent to obtain a mixture; the mixture is then subjected to a temperature T. 21 Cool down to temperature T22 Subsequently, solid-liquid separation was performed to obtain a second crystal; wherein, based on the mass of the first crystal being 100%, the mass of the solvent was 5-12%; T 21 ≥30℃, T 22 ≤22℃;

[0030] (3) Optionally repeat step (2) to obtain the bio-based succinic acid particles.

[0031] This invention designs a crystallization process and proposes a solvent-controlled temperature crystallization technique. Specifically, in step (1), cooling crystallization is performed at a relatively slow rate (v1≤1℃ / min), and the resulting first crystal includes both large and small particles. In step (2), a small amount of solvent (5-12% of the mass of the first crystal) is added for dissolution. Due to the larger specific surface area and higher surface energy of the small particles, their solubility is greater than that of the large particles, resulting in a faster dissolution rate. The small particles are preferentially dissolved during the dissolution process, resulting in a mixture in which the small particles are dissolved while the large particles are not dissolved or only partially dissolved. The mixture is then cooled for crystallization, and the solute in the solution precipitates on the surface of the large particles, forming larger crystals, thus obtaining the second crystal. Optionally, step (2) is repeated until the crystal with a specific D is obtained as proposed in this invention. 10 D 50 D 90 Bio-based succinic acid granules. The preparation method is simple to operate, the process parameters are easy to control, no additional reagents such as surfactants are required, it has no impact on the purity of the product, the production cost is low, and it is suitable for large-scale production.

[0032] In this invention, T 11 ≥78℃, for example, T 11 The temperature range can be 80.5℃, 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, or 88℃, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. Preferably, 80℃≤T1≤85℃.

[0033] T 12 ≤20℃, for example, T 12 The temperature range can be 8℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, or 19℃, as well as specific values ​​between these values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. Preferably, 10℃ ≤ T 12 ≤20℃.

[0034] v1 ≤ 1℃ / min, for example, v1 can be 0.1℃ / min, 0.2℃ / min, 0.3℃ / min, 0.4℃ / min, 0.5℃ / min, 0.6℃ / min, 0.7℃ / min, 0.8℃ / min or 0.9℃ / min, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range. Preferably, 0.2℃ / min ≤ v1 ≤ 0.8℃ / min.

[0035] Preferably, the succinic acid content in the bio-based succinic acid supersaturated solution is 30-40% by mass, for example, it can be 31%, 32%, 33%, 34%, 35%, 36%, 37%, 38% or 39%, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0036] In this invention, the bio-based succinic acid supersaturated solution can be prepared by mixing commercially available bio-based succinic acid (SA200P01 from Liaoning Kingfa Biomaterials Co., Ltd.) with water, and the final bio-based succinic acid supersaturated solution contains 30-40% succinic acid by mass.

[0037] Preferably, the cooling in step (1) is carried out under stirring conditions.

[0038] Preferably, the stirring speed for cooling in step (1) is 30-100 rpm, for example, it can be 40 rpm, 45 rpm, 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm, 85 rpm, 90 rpm or 95 rpm, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0039] Preferably, the temperature-holding crystallization in step (1) is carried out under static conditions.

[0040] Preferably, the holding time for crystallization in step (1) is 0.5-2.5 h, for example, it can be 0.6 h, 0.8 h, 1 h, 1.2 h, 1.3 h, 1.4 h, 1.5 h, 1.6 h, 1.8 h, 2 h, 2.2 h or 2.4 h, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0041] Preferably, the solid-liquid separation method in step (1) includes centrifugation, filtration or membrane separation.

[0042] Preferably, the D of the first crystal 50 The particle size is 200-300 μm, for example, it can be 210 μm, 220 μm, 230 μm, 240 μm, 250 μm, 260 μm, 270 μm, 280 μm or 290 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0043] Preferably, the first crystal has a D10 of 50-200 μm and a D90 of 300-500 μm.

[0044] In step (2), with the mass of the first crystal as 100%, the mass of the solvent is 5-12%, for example, it can be 5.5%, 6%, 6.5%, 7%, 7.5%, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11% or 11.5%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0045] Preferably, the solvent is water with a temperature ≥70°C, such as water with temperatures of 72°C, 74°C, 75°C, 76°C, 78°C, 80°C, 82°C or 85°C, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, but 70-80°C is further preferred.

[0046] Preferably, the mixing in step (2) is carried out under stirring conditions.

[0047] Preferably, the mixing speed in step (2) is 100-300 rpm, for example, it can be 120 rpm, 140 rpm, 150 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm or 280 rpm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0048] Preferably, the mixing time in step (2) is 10-60 min, for example, it can be 15 min, 20 min, 25 min, 30 min, 35 min, 40 min, 45 min, 50 min or 55 min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range, and 20-40 min is further preferred.

[0049] Preferably, the temperature of the mixture in step (2) is 30-40°C, for example, it can be 31°C, 32°C, 33°C, 34°C, 35°C, 36°C, 37°C, 38°C or 39°C, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0050] In step (2), T 21 ≥30℃, for example, T 21 The temperature range can be 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃, 39℃, 40℃, 42℃, or 45℃, as well as specific values ​​between these values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. Preferably, 30℃ ≤ T 12 ≤40℃.

[0051] T 22 ≤22℃, for example, T 22 The temperature range can be 8℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, or 19℃, as well as specific values ​​between these values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list all the specific values ​​included in the range. Preferably, 10℃ ≤ T 22 ≤20℃.

[0052] Preferably, the cooling rate in step (2) is 0.8-1.5℃ / min, for example, it can be 0.9℃ / min, 1℃ / min, 1.1℃ / min, 1.2℃ / min, 1.3℃ / min or 1.4℃ / min, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0053] Preferably, the cooling in step (2) is carried out under stirring conditions.

[0054] Preferably, the stirring speed for cooling in step (2) is 100-300 rpm, for example, it can be 120 rpm, 140 rpm, 150 rpm, 160 rpm, 180 rpm, 200 rpm, 220 rpm, 250 rpm or 280 rpm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0055] Preferably, step (2) after cooling down to temperature T2 further includes a step of maintaining the temperature for crystal growth.

[0056] Preferably, the temperature-controlled crystal growth is carried out under static conditions.

[0057] Preferably, the time for holding the temperature to grow crystals is ≤2 h, for example, it can be 0 (no temperature holding required for crystal growth), 0.1 h, 0.2 h, 0.5 h, 0.6 h, 0.8 h, 1 h, 1.2 h, 1.5 h or 1.8 h, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0058] Preferably, the solid-liquid separation method in step (2) includes centrifugation, filtration or membrane separation.

[0059] Preferably, the D of the second crystal 50 The particle size is 150-500 μm, for example, it can be 160 μm, 180 μm, 200 μm, 220 μm, 250 μm, 280 μm, 300 μm, 320 μm, 350 μm, 380 μm, 400 μm, 420 μm, 450 μm or 480 μm, as well as specific values ​​between the above values. Due to space limitations and for the sake of brevity, this invention will not exhaustively list the specific values ​​included in the range.

[0060] It should be noted that if the D of the second crystal obtained in step (2) 10 D 50 D 90 If the requirements of this invention are met, there is no need to repeat step (2), and the second crystal is the target product; if the particle size characteristics of the second crystal obtained in step (2) do not meet the requirements of this invention, then step (2) is repeated until bio-based succinic acid particles that meet the requirements of this invention are obtained.

[0061] The number of repetitions of step (2) can be 0, 1, 2, 3, 4, 5, 6, etc. Preferably, the number of repetitions of step (2) is 1-3 times, and more preferably 1-2 times.

[0062] Preferably, the solid-liquid separation further includes washing and / or drying steps.

[0063] Preferably, the washing reagent used for washing includes an alcohol-water mixture.

[0064] Preferably, the alcohol in the alcohol-water mixture includes any one or a combination of at least two of methanol, ethanol, isopropanol, and n-propanol, with ethanol being more preferred.

[0065] Preferably, the alcohol content in the alcohol-water mixture is 60-75% by mass, for example, 62%, 65%, 68%, 70%, 72% or 74%, and specific values ​​between the above values. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0066] Preferably, the drying method includes blower drying or spray drying.

[0067] Preferably, the drying temperature is 80-100℃, for example, it can be 82℃, 85℃, 88℃, 90℃, 92℃, 95℃ or 98℃, and specific values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific values ​​included in the range.

[0068] As a preferred embodiment of the present invention, the method for preparing the bio-based succinic acid particles includes the following steps:

[0069] (1) A bio-based supersaturated succinic acid solution with a succinic acid mass content of 30-40% is transferred from a temperature T 11 Cool down to temperature T at a rate v1 and a stirring speed of 30-100 rpm. 12 Then, stop stirring and maintain the temperature for crystallization for 0.5-2.5 h. Separate the solid and liquid phases to obtain D. 50 The first crystal has a particle size of 200-300 μm; where T 11 ≥78℃, T 12 ≤20℃, v1≤1℃ / min;

[0070] (2) The first crystal and the solvent are stirred and mixed at a speed of 100-300 rpm for 20-40 min to obtain a mixture; the solvent is water at a temperature ≥70℃, and the mass of the solvent is 5-12% based on the mass of the first crystal as 100%;

[0071] The mixture is taken from temperature T 21 The temperature was lowered to temperature T at a cooling rate of 0.8-1.5℃ / min and a stirring speed of 100-300 rpm. 22 Afterwards, stirring was stopped, and the mixture was kept at the temperature for 0-2 hours to crystallize. Solid-liquid separation was then performed to obtain the second crystal; wherein, T... 21 ≥30℃, T 22 ≤22℃;

[0072] (3) Repeat step (2) 1-3 times, and dry the obtained solid to obtain the bio-based succinic acid particles.

[0073] It should be noted that the preparation method of the bio-based succinic acid particles is not limited to the preparation method provided in the second aspect of the present invention. Those skilled in the art can also select other methods or routes to obtain the bio-based succinic acid particles proposed in the present invention. For example, commercially available succinic acid can be screened multiple times to obtain the bio-based succinic acid particles with a specific particle size of the present invention.

[0074] Thirdly, the present invention provides the use of bio-based succinic acid particles as described in the first aspect in the preparation of polyesters, 1,4-butanediol or five-membered heterocyclic compounds.

[0075] Preferably, the polyester comprises polybutylene succinate (PBS), polybutylene succinate-co-terephthalate (PBST), or alkyd resin.

[0076] Preferably, the five-membered heterocyclic compound includes succinic anhydride, γ-butyrolactone, or tetrahydrofuran.

[0077] Compared with the prior art, the present invention has the following beneficial effects:

[0078] The bio-based succinic acid particles provided by this invention have a particle size within a specific range, and are based on D... 10 D 50 D 90 The design endows it with specific particle size distribution characteristics, which on the one hand solves the problems of dust and inhalation in the application of traditional succinic acid fine powder, and on the other hand significantly reduces the moisture absorption rate of the bio-based succinic acid particles, avoiding the problem of agglomeration and clumping during long-term storage, and improving storage performance and downstream application performance; at the same time, it can also ensure that the bio-based succinic acid particles have good flowability and good processing performance, and make the downstream products such as polyester prepared from the bio-based succinic acid particles have good mechanical properties. Detailed Implementation

[0079] The technical solution of the present invention will be further illustrated below through specific embodiments. Those skilled in the art should understand that the embodiments described are merely illustrative of the present invention and should not be construed as limiting the invention in any way.

[0080] The terms “comprising,” “including,” “having,” “containing,” or any other variations thereof, as used herein, are intended to cover non-exclusive inclusion. For example, a composition, step, method, article, or apparatus that includes the listed elements is not limited to those elements and may also include other elements not expressly listed or elements inherent to such composition, step, method, or article.

[0081] In this invention, features specified as "first" and "second" may explicitly or implicitly include one or more of these features, used to distinguish and describe features, without any order or emphasis. In the description of this invention, unless otherwise stated, "multiple" means two or more.

[0082] In the following specific embodiments of the present invention, the relevant testing methods for bio-based succinic acid are as follows:

[0083] (1) Particle size (D) 10 D 50 D90 )

[0084] Particle size distribution was measured using laser diffraction method according to standard GB / T 19077-2024, and a Malvern Mastersizer 3000 laser particle size analyzer was used to obtain D. 10 D 50 D 90 Specifically, the test sample was added to cyclohexane at a mass ratio of 1:3, and ultrasonically treated for 2 minutes (ultrasonic conditions: 40kHz, 150W, ice bath temperature control ≤30℃). The shading degree was controlled at 10-15%. The optical model adopted Mie scattering theory (applicable range 0.1-1000μm). The instrument parameters were set as follows: refractive index: succinic acid 1.45, cyclohexane 1.426; background measurement time: 10 seconds; the average value was taken from 3 tests.

[0085] (2) Purity

[0086] The results were obtained by testing according to the method in standard GB / T 34686-2017.

[0087] (3) Crystallinity

[0088] The crystallinity of bio-based succinic acid was tested using an X-ray powder diffractometer, specifically a Rigaku MINIFLEX 600 instrument.

[0089] X-ray source: Cu target; wavelength λ is Kα radiation (λ = 1.5406 Å), Kα2 / Kα1 doublet intensity ratio is about 0.5.

[0090] Filtering system: Ni filter, used to filter Kβ radiation (λ = 1.3922 Å) generated by Cu target, to improve Kα monochromaticity.

[0091] Operating conditions: tube voltage 40KV, tube current 40mA, scanning range 5°~50° (2θ), continuous scanning mode, scanning speed 2~5° / min, step size 0.02°.

[0092] Slit settings: diverging slit (DS) 1°, receiving slit (RS) 0.3 mm, scattering slit (SS) 1°.

[0093] Detector: A scintillation counter (SC) is used to detect the signal with a time constant of 0.5 s.

[0094] Sample preparation: Bio-based succinic acid is uniformly pressed into the glass sample cell to ensure a flat sample surface and avoid preferential orientation.

[0095] Data processing: The background was subtracted using Jade or HighScore Plus software, the data was smoothed, and the crystallinity was calculated (calculation formula: crystallinity = crystal peak area / total diffraction peak area × 100%).

[0096] Environmental control: Laboratory temperature 25±1℃, relative humidity ≤40%, to reduce air scattering interference.

[0097] (4) Moisture absorption rate

[0098] Take a dry and clean weighing bottle and measure its mass as m0; add the sample to be tested with a mass of m to the weighing bottle, and then place it open in a constant temperature and humidity aging chamber at 25℃ and 65% humidity. After 24 hours, take it out and weigh it to obtain the mass m3 (mass of weighing bottle + sample). The moisture absorption rate is 100% × (m3 - m0 - m) / m.

[0099] The following will use several embodiments as examples to describe in detail the bio-based succinic acid particles and their preparation method according to the present invention, but the bio-based succinic acid particles and their preparation method are not limited to these embodiments.

[0100] In the following detailed embodiments, all materials for which no preparation method is provided are commercially available chemicals.

[0101] Example 1

[0102] A bio-based succinic acid granule, the preparation method of which is as follows:

[0103] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 35% was cooled from 82°C to 18°C ​​at a rate of 0.5°C / min and a stirring speed of 50 rpm. After stopping the stirring, the solution was crystallized at 18°C ​​for 1.5 h. Solid-liquid separation was performed to obtain the first crystal, which contained large and small particles. 50 The particle size is 244 μm, D 10 It is 75μm, D 90 It is 454μm;

[0104] (2) Add hot water at 75°C (the mass of the hot water is 8% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 200 rpm for 30 min to obtain a mixture at 35°C;

[0105] The mixture was cooled from 35°C to 20°C at a rate of 1°C / min and a stirring speed of 200 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0106] (3) Repeat step (2) once, and dry the collected solid at 82°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0107] Example 2

[0108] A bio-based succinic acid granule, the preparation method of which is as follows:

[0109] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 33% was cooled from 80°C to 15°C at a rate of 0.5°C / min and a stirring speed of 50 rpm. After stopping the stirring, the solution was held at 15°C for 2 hours to crystallize. Solid-liquid separation was performed to obtain the first crystal, which contained large and small particles. 50 The particle size is 275 μm, D 10 It is 62μm, D 90 It is 476 μm;

[0110] (2) Add hot water at 70°C (the mass of the hot water is 10% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 150 rpm for 30 min to obtain a mixture at 32°C;

[0111] The mixture was cooled from 32°C to 15°C at a rate of 1°C / min and a stirring speed of 150 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0112] (3) Repeat step (2) once, and dry the collected solid at 85°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0113] Example 3

[0114] A bio-based succinic acid granule, the preparation method of which is as follows:

[0115] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 32% was cooled from 85°C to 15°C at a rate of 0.5°C / min and a stirring speed of 50 rpm. After stopping the stirring, the solution was held at 15°C for 1 h to crystallize. Solid-liquid separation was performed to obtain the first crystal, which contained large and small particles. D 50 The particle size is 264 μm, D 10 It is 86μm, D 90 It is 494μm;

[0116] (2) Add hot water at 80°C (the mass of the hot water is 6% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 200 rpm for 30 min to obtain a mixture at 40°C.

[0117] The mixture was cooled from 40°C to 15°C at a rate of 1°C / min and a stirring speed of 200 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0118] (3) Repeat step (2) twice, and dry the collected solid at 88°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0119] Example 4

[0120] A bio-based succinic acid granule, the preparation method of which is as follows:

[0121] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 30% was cooled from 82°C to 18°C ​​at a rate of 0.5°C / min and a stirring speed of 50 rpm. After stopping the stirring, the solution was held at 18°C ​​for 1.5 h to crystallize. Solid-liquid separation was performed to obtain the first crystal, which contained large and small particles. D 50 The particle size is 280 μm, D 10 It is 52μm, D 90 It is 414 μm;

[0122] (2) Add hot water at 80°C (the mass of the hot water is 8% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 250 rpm for 30 min to obtain a mixture at 35°C.

[0123] The mixture was cooled from 35°C to 15°C at a rate of 1°C / min and a stirring speed of 150 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0124] (3) Repeat step (2) twice, and dry the collected solid at 90°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0125] Example 5

[0126] A bio-based succinic acid granule, the preparation method of which is as follows:

[0127] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 34% was cooled from 80°C to 15°C at a rate of 0.5°C / min and a stirring speed of 50 rpm. After stopping the stirring, the solution was crystallized at 15°C for 1 h. Solid-liquid separation was performed to obtain the first crystal, which contained large and small particles. 50 The particle size is 245 μm, D 10 80μm, D 90 It is 461 μm;

[0128] (2) Add hot water at 80°C (the mass of the hot water is 5% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 200 rpm for 30 min to obtain a mixture at 40°C.

[0129] The mixture was cooled from 40°C to 15°C at a rate of 1°C / min and a stirring speed of 100 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0130] (3) Repeat step (2) twice, and dry the collected solid at 80°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0131] Example 6

[0132] A bio-based succinic acid granule, the preparation method of which is as follows:

[0133] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 33% was cooled from 81°C to 15°C at a rate of 0.5°C / min and a stirring speed of 50 rpm. After stopping the stirring, the solution was held at 15°C for 1 h to crystallize. Solid-liquid separation was performed to obtain the first crystal, which contained large and small particles. 50 The particle size is 242 μm, D 10 It is 79μm, D 90 It is 455μm;

[0134] (2) Add hot water at 80°C (the mass of the hot water is 6% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 200 rpm for 30 min to obtain a mixture at 40°C.

[0135] The mixture was cooled from 40°C to 15°C at a rate of 1°C / min and a stirring speed of 100 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0136] (3) Repeat step (2) twice, and dry the collected solid at 85°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0137] Example 7

[0138] This embodiment provides a bio-based succinic acid particle, the preparation method of which includes: sieving the bio-based succinic acid particle provided in Comparative Example 4 to achieve a Dg 10 Particle size, D 50 Particle size, D 90 The particle size is shown in Table 1.

[0139] Comparative Example 1

[0140] A bio-based succinic acid granule, the preparation method of which is as follows:

[0141] A supersaturated solution of bio-based succinic acid with a mass content of 33% was cooled from 80°C to 15°C at a rate of 0.5°C / min and a stirring speed of 100 rpm. After stirring was stopped, the solution was crystallized at 15°C for 2 hours. The solid and liquid were separated, and the collected solid was dried at 85°C to obtain the bio-based succinic acid particles. The specific information is shown in Table 1.

[0142] Comparative Example 2

[0143] A bio-based succinic acid particle, the preparation method of which differs from that of Example 1 only in step (1), as follows:

[0144] (1) A bio-based supersaturated succinic acid solution with a succinic acid content of 35% was cooled from 82°C to 18°C ​​at a rate of 2°C / min and a stirring speed of 50 rpm. After stirring was stopped, the solution was held at 18°C ​​for 1.5 h to crystallize. Solid-liquid separation was then performed to obtain the first crystal, whose D 50 The particle size is 187 μm;

[0145] Steps (2) and (3) are the same as in Example 1, and the bio-based succinic acid is obtained. Its specific information is shown in Table 1.

[0146] Comparative Example 3

[0147] A bio-based succinic acid granule, the preparation method of which is as follows:

[0148] (1) The first crystal was obtained using the same method as in step (1) of Example 1;

[0149] (2) Add hot water at 75°C (the mass of the hot water is 20% of the mass of the first crystal) to the first crystal obtained in step (1), and stir and mix at 200 rpm for 30 min to obtain a mixture at 35°C;

[0150] The mixture was cooled from 35°C to 20°C at a rate of 1°C / min and a stirring speed of 200 rpm, and then stirring was stopped. Solid-liquid separation was performed to obtain the second crystal.

[0151] (3) Repeat step (2) once, and dry the collected solid at 82°C to obtain the bio-based succinic acid particles, the specific information of which is shown in Table 1.

[0152] Comparative Example 4

[0153] The specific information of commercially available bio-based succinic acid granules (Shandong Landian Biotechnology Co., Ltd., bio-based succinic acid) is shown in Table 1.

[0154] Comparative Example 5

[0155] This comparative example provides a bio-based succinic acid particle, the preparation method of which includes: sieving the bio-based succinic acid particle obtained in Example 1 to achieve a Dx 10 Particle size, D 50 Particle size, D 90 The particle size is shown in Table 1.

[0156] Table 1

[0157]

[0158] As can be seen from the data in Table 1, the bio-based succinic acid particles provided by this invention have specific D... 10 D 50 D 90 The particle size distribution characteristics avoid problems such as dust generation and inhalation during the application of fine succinic acid powder, and significantly reduce moisture adsorption, resulting in low moisture absorption of the bio-based succinic acid particles. This prevents agglomeration and clumping during long-term storage and improves storage performance. The crystallinity of the bio-based succinic acid particles is ≥85%, giving them higher mechanical strength and reducing damage during transportation. The purity of the bio-based succinic acid particles is high, far exceeding the standards of commercially available polymer-grade particles, making them suitable for high-end applications.

[0159] As can be seen from Example 6 and Comparative Examples 1-3, the bio-based succinic acid particles D 10 D 50 D 90 If at least one of them is too small, its moisture absorption rate will increase.

[0160] As can be seen from Examples 1-7 and Comparative Example 4, the bio-based succinic acid particles provided by the present invention have a lower moisture absorption rate compared to commercially available bio-based succinic acid particles.

[0161] Crystal structure testing:

[0162] X-ray powder diffraction (XRD) was performed on the bio-based succinic acid particles provided in Example 1 and Comparative Example 4. The instrument was a Rigaku MINIFLEX 600 with a Cu target; wavelength λ: Kα radiation (λ = 1.5406 Å), Kα2 / Kα1 doublet intensity ratio approximately 0.5. A Ni filter was used to filter Kβ radiation (λ = 1.3922 Å) generated by the Cu target, improving Kα monochromaticity. The tube voltage was 40 kV, tube current 40 mA, scanning range 5°–50°, scanning speed 2–5° / min, step size 0.02°, and divergence slit 1°. The characteristic peaks and relative peak intensities represented by the diffraction angle 2θ are shown in Table 2.

[0163] Table 2

[0164]

[0165] The application of the bio-based succinic acid particles of the present invention will be described in detail below using application examples, but the application of the bio-based succinic acid particles is not limited to these application examples.

[0166] Application examples

[0167] The preparation method of PBS includes the following steps:

[0168] (1) Bio-based succinic acid particles (from Examples 1-7 and Comparative Examples 1-5, respectively) were mixed with 1,4-butanediol (BDO, purity 99.7%, purchased from Liaoning Kingfa Biomaterials Co., Ltd.) at a molar ratio of 1:1.2 and esterified at 150°C for 3 h to obtain esterified products;

[0169] (2) The ester obtained in step (1), catalyst (tetrabutyl titanate), branching agent (glycerol) and heat stabilizer (triethyl phosphate) are placed in a reaction vessel. The total mass of succinic acid and 1,4-butanediol is 100%. The amount of catalyst is such that the mass of Ti element is 100 ppm, the amount of branching agent is such that the mass of hydroxyl group is 500 ppm, and the amount of heat stabilizer is such that the mass of P element is 20 ppm. First, the temperature is raised to 220℃ and 2 kPa for prepolymerization reaction for 2 h. Then, the temperature is raised to 240℃ and the pressure is controlled at 80 Pa for further reaction for 2 h. The obtained polymer product is extruded and granulated, which is the PBS.

[0170] The PBS prepared above was injection molded into specimens according to the method in standard ISO 527-2-2012, and the tensile strength and elongation at break were tested. The test data are shown in Table 3.

[0171] Table 3

[0172]

[0173] According to the data in Table 3, the bio-based succinic acid particles provided by this invention have specific D... 10 D 50 D 90 The PBS resin prepared from the bio-based succinic acid particles has superior tensile strength and elongation at break; the tensile strength of the PBS resin is 36.5~41.2 MPa, and the elongation at break is 250~265%.

[0174] As can be seen from Examples 5, 7 and 6, the crystallinity of the bio-based succinic acid particles is in the range of 90-95%, which is beneficial to further improve the tensile strength of PBS resin while ensuring a high elongation at break.

[0175] As can be seen from Example 6 and Comparative Examples 1-4, the bio-based succinic acid (i.e., D) with a specific particle size of the present invention was not used. 10 D 50 D 90 (If at least one of them is too small), the tensile strength and elongation at break of the resulting PBS resin are reduced.

[0176] As can be seen from Example 4 and Comparative Example 5, the particle size of the bio-based succinic acid particles is too large, which slows down the dissolution and diffusion rate during melt polycondensation, resulting in a reduced contact area with the diol and a decrease in the synthesis reaction rate. This leads to a wider molecular weight distribution (PDI) of the polyester, which in turn results in poorer mechanical properties of the prepared polyester.

[0177] The applicant declares that this invention illustrates the bio-based succinic acid granules, their preparation method, and applications through the above embodiments. However, this invention is not limited to the above embodiments, meaning that this invention does not necessarily rely on the above embodiments for implementation. Those skilled in the art should understand that any improvements to this invention, equivalent substitutions of raw materials, additions of auxiliary components, and selection of specific methods, etc., all fall within the protection and disclosure scope of this invention.

Claims

1. A bio-based succinic acid granule, characterized in that, The bio-based succinic acid particles have D 10 Particle size is 150-300 μm, D 50 Particle size is 300-500 μm, D 90 The particle size is 500-800 μm.

2. The bio-based succinic acid granules according to claim 1, characterized in that, The purity of the bio-based succinic acid particles is ≥99.5%; the crystallinity of the bio-based succinic acid particles is ≥84%.

3. The bio-based succinic acid granules according to claim 1, characterized in that, The moisture absorption rate of the bio-based succinic acid particles is ≤0.5%.

4. A method for preparing bio-based succinic acid particles as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: (1) dissolving a bio-based succinic acid supersaturated solution at temperature T. 11 Cool to temperature T at a rate of v1 12 Subsequently, through temperature-controlled crystallization and solid-liquid separation, the first crystal was obtained; wherein, T 11 ≥78℃, T 12 ≤20℃, v1≤1℃ / min; (2) Mix the first crystal with a solvent to obtain a mixture; remove the mixture from temperature T 21 Cool down to temperature T 22 Subsequently, solid-liquid separation was performed to obtain a second crystal; wherein, based on the mass of the first crystal being 100%, the mass of the solvent was 5-12%; T 21 ≥30℃, T 22 ≤22℃; (3) Optionally repeat step (2) to obtain the bio-based succinic acid particles.

5. The preparation method according to claim 4, characterized in that, The bio-based succinic acid supersaturated solution contains 30-40% succinic acid by mass; the cooling in step (1) is carried out under stirring conditions; the stirring speed for cooling in step (1) is 30-100 rpm; the holding time for crystallization in step (1) is 0.5-2.5 h; the D of the first crystal 50 The particle size is 200-300 μm.

6. The preparation method according to claim 4, characterized in that, The solvent is water with a temperature ≥70℃; the mixing in step (2) is carried out under stirring conditions; the stirring speed in step (2) is 100-300 rpm; the mixing time in step (2) is 10-60 min; the temperature of the mixture in step (2) is 30-40℃.

7. The preparation method according to claim 4, characterized in that, The cooling rate in step (2) is 0.8-1.5℃ / min; the cooling in step (2) is carried out under stirring conditions; the stirring speed in step (2) is 100-300 rpm; after cooling to temperature T2, step (2) further includes a step of holding the temperature to grow crystals; the time for holding the temperature to grow crystals is ≤2 h; the D of the second crystal 50 The particle size is 150-500 μm.

8. The preparation method according to claim 4, characterized in that, Step (2) is repeated 1-3 times.

9. The use of bio-based succinic acid particles as described in any one of claims 1-3 in the preparation of polyesters, 1,4-butanediol or five-membered heterocyclic compounds.

10. The application according to claim 9, characterized in that, The polyester includes polybutylene succinate, polybutylene succinate-co-terephthalate, or alkyd resin; the five-membered heterocyclic compound includes succinic anhydride, γ-butyrolactone, or tetrahydrofuran.

Images