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

Abstract

The invention provides bio-based succinic acid and a preparation method and application thereof, the median particle size of the bio-based succinic acid is 300-500 [mu] m, and the bio-based succinic acid comprises the following particles in percentage by mass: 0-10% of particles with the particle size of d1, 30-40% of particles with the particle size of d2, 40-50% of particles with the particle size of d3 and 8-18% of particles with the particle size of d4, d1 is less than 150 [mu] m, 150 [mu] m < = d2 < 300 [mu] m, 300 [mu] m < = d3 < 500 [mu] m, and d4 > = 500 [mu] m. The bio-based succinic acid is large in particle size, controllable in particle size distribution and good in uniformity, not only solves the problem of dust raising in succinic acid application, but also can reduce the adhesive force among particles and avoid the problems of agglomeration and caking, so that the storage time of the bio-based succinic acid is prolonged, the succinic acid has proper friction force, and the service life of the bio-based succinic acid is prolonged. The storage performance and the downstream application performance are improved, and the application requirements of various scenes are met.

Description

Technical Field

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

[0002] Succinic acid (succinic acid) is an important chemical monomer with wide applications in food, pharmaceuticals, fine chemicals, and biodegradable plastics. There are two main methods for preparing succinic acid: one is the traditional chemical synthesis method, such as the catalytic reduction of butenacite to obtain succinic acid, or the hydrolysis of succinic acid to obtain succinic acid, etc., the products obtained in these methods are collectively referred to as petroleum-based succinic acid; the other is the microbial fermentation method, which uses renewable biomass resources as raw materials and obtains bio-based succinic acid through fermentation by succinic acid-producing strains. With increasingly stringent environmental regulations, bio-based succinic acid, with its green and environmentally friendly advantages, is expected to accelerate its replacement of petroleum-based succinic acid and become the mainstream product in the succinic acid market.

[0003] Crystallization is a crucial purification step in the production process of bio-based succinic acid. For example, in the method for separating and purifying succinic acid from fermentation broth disclosed in CN102363594A, the fermentation broth is first clarified using ultrafiltration, then decolorized using resin instead of traditional activated carbon, and finally succinic acid crystals are obtained directly through crystallization. CN102942472A discloses a method for separating and extracting succinic acid from fermentation broth, which includes sequential steps of membrane filtration, hydrochloric acid acidification, concentration crystallization, and circulating cooling crystallization-concentration crystallization to finally obtain solid succinic acid.

[0004] Currently, most processes in the industry employ continuous crystallization, which, due to the crystal characteristics of succinic acid, results in a median particle size D. 50 Generally, succinic acid particles are less than 150 μm in diameter, with a particle size distribution span >3, exhibiting problems such as small particle size, wide particle size distribution range, and poor uniformity. Therefore, most existing succinic acid suppliers in the market offer products in powder form. In downstream applications, the small powder size not only causes severe dust generation, hindering feeding, but also makes the fine powder prone to agglomeration during storage. High agglomeration strength leads to short shelf life and deteriorated performance at the application end. Furthermore, existing succinic acid has low friction, limiting its use in some scenarios, such as as bath salts, where its low friction results in reduced user comfort and detergency.

[0005] Therefore, developing a succinic acid with low agglomeration strength and suitable friction 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, its preparation method, and its application. The bio-based succinic acid comprises a particulate component with a specific particle size distribution. The particle size is relatively large and the particle size distribution is controllable, resulting in high particle uniformity. This effectively solves the problems of dust, agglomeration, and clumping in succinic acid, improves storage performance, and also gives the succinic acid suitable friction, thus meeting the application needs in various scenarios.

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

[0008] In a first aspect, the present invention provides a bio-based succinic acid, wherein the median particle size of the bio-based succinic acid is 300-500 μm, and the bio-based succinic acid comprises particles of the following particle sizes by mass percentage:

[0009] Particles with a diameter of d1 account for 0-10%.

[0010] Particles with a diameter of d2 account for 30-40%.

[0011] Particles with a diameter of d3 account for 40-50%.

[0012] Particles with a diameter of d4 account for 8-18%.

[0013] Among them, d1<150 μm, 150 μm≤d2<300 μm, 300 μm≤d3<500 μm, d4≥500 μm.

[0014] The bio-based succinic acid provided by this invention has a particle component with a specific particle size distribution, featuring a relatively large median particle size, controllable particle size distribution, and good particle size uniformity. This effectively solves the dust problem in succinic acid applications and reduces particle adhesion, preventing agglomeration and clumping, extending storage time, and improving storage performance and downstream application performance. Furthermore, the bio-based succinic acid provides suitable friction, better meeting the application needs of special scenarios such as bath salts; too low friction reduces comfort and cleaning efficiency, while too high friction may cause skin irritation.

[0015] 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.

[0016] In this invention, the median particle size (D) of the bio-based succinic acid is... 50The 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, for example, it can be 320-400 μm.

[0017] In the bio-based succinic acid, the mass percentage of particles with a particle size of d1 is 0-10%, for example, it can be 0.1%, 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9% or 9.5%, 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, for example, it can be 3-9%.

[0018] d1 < 150 μm, for example, can be 1 μm, 2 μm, 4 μm, 6 μm, 8 μm, 10 μm, 20 μm, 40 μm, 50 μm, 60 μm, 80 μm, 100 μm, 120 μm or 140 μm, as well as 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.

[0019] In the bio-based succinic acid, the mass percentage of particles with a particle size of d2 is 30-40%, 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, for example, it can be 31.5-35.5%.

[0020] 150 μm ≤ d2 < 300 μm, for example, d2 can be 160 μm, 180 μm, 200 μm, 220 μm, 240 μm, 250 μm, 260 μm or 280 μm, as well as 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.

[0021] In the bio-based succinic acid, the mass percentage of particles with a particle size of d3 is 40-50%, for example, it can be 41%, 42%, 43%, 44%, 45%, 46%, 47%, 48% or 49%, 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, for example, it can be 44.5-49.5%.

[0022] 300 μm ≤ d3 < 500 μm, for example, d3 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 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.

[0023] In the bio-based succinic acid, the mass percentage of particles with a particle size of d4 is 8-18%, for example, it can be 9%, 10%, 11%, 12%, 13%, 14%, 15%, 16% or 17%, 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, for example, it can be 9.5-15.5%.

[0024] d4 ≥ 500 μm, for example, d4 can be 510 μm, 520 μm, 540 μm, 550 μm, 560 μm, 580 μm, 600 μm, 620 μm, 650 μm, 680 μm, 700 μm, 720 μm, 750 μm, 780 μm, 800 μm, 820 μm, 850 μm, 880 μm, 900 μm, 920 μm, 950 μm, 980 μm or 1000 μm, as well as 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] For example, the mass content of particle components in each particle size range in the bio-based succinic acid is obtained by sieving, including the following steps: taking a bio-based succinic acid sample with mass m; sieving the sample sequentially through sieves with apertures of 500 μm, 300 μm, and 150 μm, and weighing each sieved group; the mass of particles that do not pass through the 500 μm sieve is recorded as m4; the mass of particles that pass through the 500 μm sieve but not through 300 μm is recorded as m3; the mass of particles that pass through the 300 μm sieve but not through 150 μm is recorded as m2; the mass of particles that pass through the 150 μm sieve is recorded as m1; the mass content of particles with particle size d1 = 100% × m1 / m; the mass content of particles with particle size d2 = 100% × m2 / m; the mass content of particles with particle size d3 = 100% × m3 / m; the mass content of particles with particle size d4 = 100% × m4 / m.

[0026] In this invention, the particle size distribution of the bio-based succinic acid spans <1.4, and can be, for example, 0.85, 0.9, 0.92, 0.94, 0.95, 0.98, 1, 1.02, 1.05, 1.08, 1.1, 1.12, 1.15, 1.18, 1.2, 1.22, 1.25, 1.28, 1.3, 1.32, 1.35, or 1.38, 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.

[0027] The formula for calculating the particle size distribution span is: Span = (D 90 -D 10 ) / D 50 Where Span represents the particle size distribution span, and D 10 D 50 D 90 The numbers represent the particle sizes corresponding to a cumulative volume distribution percentage of 10%, 50%, and 90% for the bio-based succinic acid, respectively.

[0028] For example, the D of the bio-based succinic acid 10 D 50 D 90 The particle size distribution can be determined using a laser particle size analyzer by referring to the standard GB / T 19077-2016 laser diffraction method.

[0029] In this invention, the X-ray powder diffraction pattern of the bio-based succinic acid has characteristic peaks at diffraction angles 2θ of 16.3±0.5°, 22.7±1.5° and 28.5±1.2°.

[0030] In this invention, the X-ray powder diffraction pattern of the bio-based succinic acid has characteristic peaks at diffraction angles 2θ of 16.3±0.3°, 21.5±0.3°, 23.9±0.3° and 29.5±0.3°.

[0031] Preferably, 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 22.7±1.5° is 80-150%, for example, it can be 82%, 85%, 88%, 90%, 92%, 95%, 98%, 100%, 102%, 105%, 108%, 110%, 112%, 115%, 118%, 120%, 122%, 125%, 128%, 130%, 132%, 135%, 138%, 140%, 145%, or 148%, as well as specific point values ​​between the above point values. Due to space limitations and for the sake of brevity, the present 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 28.5 ± 1.2° is 50-70%, for example, it can be 52%, 54%, 55%, 56%, 58%, 60%, 62%, 64%, 65%, 66%, or 68%, as well as 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.

[0032] In this invention, the X-ray powder diffraction pattern of the bio-based succinic acid has a characteristic peak at a diffraction angle 2θ of 34±0.5°. 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 34±0.5° is 0.5-3.5%, for example, it can be 0.5%, 1%, 1.5%, 2%, 2.5%, 3%, or 3.5%, as well as 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.

[0033] In this invention, the half-width at half-maximum (WHM) of the bio-based succinic acid is 0.1~0.19°, for example, 0.15°~0.18°; and the crystallinity of the bio-based succinic acid is 86~95%, for example, 88~92%.

[0034] 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.

[0035] In a second aspect, the present invention provides a method for preparing bio-based succinic acid as described in the first aspect, the method comprising the following steps:

[0036] The bio-based succinic acid supersaturated solution was cooled from temperature T1 to temperature T2 at a rate v1 to carry out the first temperature-holding crystallization; then cooled from temperature T2 to temperature T3 at a rate v2 to carry out the second temperature-holding crystallization; and then cooled from temperature T3 to temperature T4 at a rate v3 to carry out the third temperature-holding crystallization, to obtain a mixture.

[0037] The mixture is separated into solid and liquid phases, and the solid is collected to obtain the bio-based succinic acid.

[0038] Among them, T1≥82℃, 50℃≤T2≤62℃, 30℃≤T3≤42℃, and T4≤22℃.

[0039] v1≤0.8℃ / min, and v1<v2≤v3.

[0040] The preparation method provided by this invention employs a specially designed crystallization process. By controlling the temperature gradient and cooling rate during crystallization, orderly crystal growth is facilitated, rapid nucleation is avoided, and the particle size and distribution of the crystals are stably controlled, resulting in the bio-based succinic acid with a large particle size, controllable particle size distribution, and high uniformity. The process parameters of this preparation method are easy to control, with low production costs and energy consumption, high repeatability, and suitability for large-scale production.

[0041] In this invention, T1 ≥ 78℃. For example, T1 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℃.

[0042] 50℃≤T2≤62℃, for example, T2 can be 51℃, 52℃, 53℃, 54℃, 55℃, 56℃, 57℃, 58℃ or 59℃, as well as 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, but preferably 55℃≤T2≤60℃.

[0043] 30℃≤T3≤42℃, for example, T3 can be 31℃, 32℃, 33℃, 34℃, 35℃, 36℃, 37℃, 38℃ or 39℃, as well as 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, but preferably 35℃≤T3≤40℃.

[0044] T4 ≤ 22℃, for example, T4 can be 8℃, 10℃, 11℃, 12℃, 13℃, 14℃, 15℃, 16℃, 17℃, 18℃, 19℃ or 21℃, as well as 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, but preferably 10℃ ≤ T4 ≤ 20℃.

[0045] 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.

[0046] Preferably, the method for preparing the bio-based succinic acid supersaturated solution includes: filtering, ion-exchange treatment, and concentration of the succinic acid fermentation broth to obtain the bio-based succinic acid supersaturated solution.

[0047] In this invention, the succinic acid fermentation broth is sourced from Liaoning Kingfa Biomaterials Co., Ltd. The succinic acid fermentation broth is not subject to excessive limitations; any broth that yields the bio-based supersaturated succinic acid solution is acceptable.

[0048] In this invention, the bio-based succinic acid supersaturated solution is obtained by concentrating the succinic acid fermentation broth to a succinic acid mass percentage of 30-40%. The bio-based succinic acid supersaturated solution also includes impurities, specifically: 1) organic acid impurities: total organic acids ≤0.25 wt%, including fumaric acid ≤0.1 wt%, malic acid ≤0.05 wt%, and lactic acid ≤0.1 wt%; 2) sugar impurities: total reducing sugars (calculated as glucose) ≤100 ppm; 3) metal ions: Fe... 3+ ≤5ppm, Ca 2+ ≤3ppm, Mg 2+ ≤3ppm; 4) Protein: ≤50ppm.

[0049] Preferably, the concentration of the succinic acid fermentation broth is 80-100 g / L, for example, it can be 82 g / L, 85 g / L, 88 g / L, 90 g / L, 92 g / L, 95 g / L or 98 g / L, 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] Preferably, the filtration method includes ceramic membrane filtration to remove bacterial residue from the succinic acid fermentation broth.

[0051] Preferably, the ion exchange treatment includes anion exchange and / or cation exchange to remove impurity inorganic salts.

[0052] Preferably, the concentration method includes vacuum distillation to obtain a bio-based supersaturated succinic acid solution with a succinic acid mass percentage of 30-40%.

[0053] Preferably, the temperature of the vacuum distillation is 80-90℃, for example, it can be 81℃, 82℃, 83℃, 84℃, 85℃, 86℃, 87℃, 88℃ or 89℃, as well as 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.

[0054] Preferably, the pH value of the bio-based succinic acid supersaturated solution is 2-3, for example, it can be 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8 or 2.9, 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.

[0055] In this invention, the rate v1 ≤ 0.8℃ / min. For example, v1 can be 0.1℃ / min, 0.2℃ / min, 0.3℃ / min, 0.4℃ / min, 0.5℃ / min, 0.6℃ / min or 0.7℃ / 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 all the specific values ​​included in the range. Preferably, 0.2℃ / min ≤ v1 ≤ 0.7℃ / min.

[0056] Preferably, 0.8℃ / min < v2 ≤ 1.5℃ / min, for example, v2 can be 0.9℃ / min, 1℃ / min, 1.05℃ / min, 1.1℃ / min, 1.15℃ / min, 1.2℃ / min, 1.25℃ / min, 1.3℃ / min, 1.35℃ / min, 1.4℃ / min or 1.45℃ / 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.

[0057] Preferably, 1.8℃ / min ≤ v3 ≤ 3.2℃ / min, for example, v3 can be 2.1℃ / min, 2.2℃ / min, 2.3℃ / min, 2.4℃ / min, 2.5℃ / min, 2.6℃ / min, 2.7℃ / min, 2.8℃ / min or 2.9℃ / min, as well as 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.

[0058] Preferably, the cooling is carried out under stirring conditions.

[0059] Preferably, the stirring speed during the cooling rate v1 is 40-90 rpm, for example, it can be 45 rpm, 50 rpm, 55 rpm, 60 rpm, 65 rpm, 70 rpm, 75 rpm, 80 rpm or 85 rpm, as well as 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.

[0060] Preferably, the stirring speed during the cooling rate v2 is 95-155 rpm, for example, it can be 105 rpm, 110 rpm, 115 rpm, 120 rpm, 125 rpm, 130 rpm, 135 rpm, 140 rpm or 145 rpm, as well as 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.

[0061] Preferably, the stirring speed during the cooling at rate v3 is 140-300 rpm, for example, it can be 160 rpm, 180 rpm, 200 rpm, 220 rpm, 240 rpm, 250 rpm, 260 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.

[0062] As a preferred embodiment of the present invention, the cooling is carried out under stirring conditions, and a lower stirring speed is used in the early stage (cooling rate v1) to reduce mechanical shear force. The stirring speed is gradually increased in the middle and later stages of cooling, which is more conducive to controlling the cooling rate. Stirring is stopped during the holding-temperature crystallization period, that is, the first holding-temperature crystallization, the second holding-temperature crystallization, and the third holding-temperature crystallization are carried out under static conditions to protect crystal growth, reduce interference to the crystal, promote crystal aging, and thus obtain the bio-based succinic acid with a large particle size and specific particle size distribution characteristics.

[0063] Preferably, the first holding temperature crystallization time is 0.4-1.5 h, for example, it can be 0.6 h, 0.8 h, 1 h, 1.1 h, 1.2 h, 1.3 h or 1.4 h, as well as specific point values ​​between the above points. Due to space limitations and for the sake of brevity, the present invention will not exhaustively list the specific point values ​​included in the range.

[0064] Preferably, the second holding time for crystallization is 0.4-1.5 h, for example, it can be 0.6 h, 0.8 h, 1 h, 1.1 h, 1.2 h, 1.3 h or 1.4 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.

[0065] Preferably, the third holding time for crystallization is 1-3 h, for example, it can be 1.2 h, 1.4 h, 1.5 h, 1.6 h, 1.8 h, 2 h, 2.2 h, 2.4 h, 2.5 h, 2.6 h or 2.8 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.

[0066] Preferably, the solid-liquid separation method includes centrifugation, filtration, or membrane separation.

[0067] Preferably, the collection of solids further includes washing and drying steps.

[0068] Preferably, the washing reagent used for washing includes an alcohol-water mixture.

[0069] 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.

[0070] 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.

[0071] 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.

[0072] As a preferred embodiment of the present invention, the method for preparing the bio-based succinic acid includes the following steps:

[0073] A bio-based supersaturated succinic acid solution with a succinic acid content of 30-40% by mass is cooled from temperature T1 to temperature T2 at a stirring rate v1 and a stirring speed of 40-90 rpm, and stirring is stopped. The solution is then held at this temperature for crystallization for 0.4-1.5 h. Next, the solution is cooled from temperature T2 to temperature T3 at a stirring rate v2 and a stirring speed of 95-155 rpm, and stirring is stopped. The solution is then held at this temperature for crystallization for 0.4-1.5 h. Finally, the solution is cooled from temperature T3 to temperature T4 at a stirring rate v3 and a stirring speed of 140-300 rpm, and stirring is stopped. The solution is then held at this temperature for crystallization for 1-3 h to obtain a mixture.

[0074] Among them, T1≥78℃, 50℃≤T2≤62℃, 30℃≤T3≤42℃, T4≤22℃; v1≤0.8℃ / min, 0.8℃ / min<v2≤1.5℃ / min, 1.8℃ / min≤v3≤3.2℃ / min.

[0075] The mixture is separated into solid and liquid phases, the solid is collected, and the solid is washed and dried to obtain the bio-based succinic acid.

[0076] It should be noted that the preparation method of the bio-based succinic acid 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 proposed in the present invention.

[0077] Thirdly, the present invention provides the use of bio-based succinic acid as described in the first aspect in the preparation of polyesters, 1,4-butanediol, five-membered heterocyclic compounds or bath salts.

[0078] Preferably, the five-membered heterocyclic compound includes succinic anhydride, γ-butyrolactone, or tetrahydrofuran.

[0079] Preferably, the polyester comprises polybutylene succinate (PBS), polybutylene succinate-co-terephthalate (PBST), or alkyd resin.

[0080] Fourthly, the present invention provides a bath salt comprising a bath salt matrix and bio-based succinic acid as described in the first aspect.

[0081] The bio-based succinic acid provided by this invention has a large particle size and specific particle size distribution characteristics, and high particle size uniformity. On the one hand, it can avoid the local enrichment of acidic substances, thereby regulating the overall dissolution balance and thus regulating the acidity of the bath salts containing it. On the other hand, it can ensure that the friction of the bath salts is within a suitable range, improving the comfort, gentleness and absorption effect of the bath salts, and improving the cleaning efficiency at the same dosage, while avoiding skin irritation.

[0082] Preferably, the bath salt matrix comprises sodium chloride (preferably from sea salt), and may also include other additives that are optionally encouraged to be added by those skilled in the art.

[0083] Preferably, the bio-based succinic acid content in the bath salt is 0.1-15% by mass, for example, it can be 0.5%, 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 11%, 12%, 13% or 14%, 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.

[0084] Compared with the prior art, the present invention has the following beneficial effects:

[0085] The bio-based succinic acid provided by this invention comprises particulate components with a specific particle size distribution. These components have a relatively large particle size, controllable particle size distribution, and good particle size uniformity. This not only solves the dust problem in succinic acid applications but also reduces the adhesion between particles, lowers agglomeration strength, and avoids aggregation and clumping issues. This extends the storage time of the bio-based succinic acid, improves its storage performance and downstream application performance, and meets the application needs of various scenarios. Furthermore, the bio-based succinic acid provides more suitable friction, better meeting the performance requirements in scenarios such as bath salts. Detailed Implementation

[0086] 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.

[0087] 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.

[0088] In this invention, features defined with "first," "second," and "third" may explicitly or implicitly include one or more of those 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.

[0089] In the following specific embodiments of the present invention, the relevant testing methods for bio-based succinic acid are as follows:

[0090] (1) Median particle size (D) 50 )

[0091] Particle size distribution was measured using laser diffraction method according to standard GB / T 19077-2016, and a Malvern Mastersizer 3000 laser particle size analyzer was used to obtain D. 10 D 50 D 90Specifically, 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℃), with the shading controlled at 10-15%; optical model: Mie scattering theory (applicable range 0.1-1000μm); instrument parameter settings: refractive index: succinic acid 1.45, cyclohexane 1.426; background measurement time: 10 seconds; the average value was taken from 3 tests.

[0092] (2) Mass content of particle components in each particle size range

[0093] Take a sample of mass m; sieve the sample sequentially through sieves with apertures of 500 μm, 300 μm, and 150 μm, with a shaking frequency of 120 times / min during the sieving process; weigh the sieved groups after each sieving; record the mass of particles that do not pass through the 500 μm sieve as m4; record the mass of particles that pass through the 500 μm sieve but not through the 300 μm sieve as m3; record the mass of particles that pass through the 300 μm sieve but not through the 150 μm sieve as m2; record the mass of particles that pass through the 150 μm sieve as m1; the mass content of particles with a particle size of d1 = 100% × m1 / m; the mass content of particles with a particle size of d2 = 100% × m2 / m; the mass content of particles with a particle size of d3 = 100% × m3 / m; the mass content of particles with a particle size of d4 = 100% × m4 / m.

[0094] (3) Agglomeration strength

[0095] The maximum pressure value resisting breakage after agglomeration of bio-based succinic acid was tested under standard compaction conditions, with the unit being N. The specific method is as follows: Weigh 50 g of the sample to be tested and pour it into a cylindrical mold with an inner diameter of 25 mm and a height of 50 mm. Gently tap the side wall of the mold until the particles naturally accumulate and compact, and scrape the surface smooth. Place the mold in a hydraulic press and apply a pressure of 10.0 MPa for 5 min to form a cylindrical agglomerate with a diameter of 25 cm and a height of 30 mm. Transfer the agglomerate to a texture analyzer testing platform (TA.XT Plus type, equipped with a 500 N load sensor). Using a cylindrical probe with a diameter of 15 mm, press vertically at a speed of 1 mm / s until the agglomerate is completely broken. Record the maximum force value (N) in the force-displacement curve as the agglomerate strength.

[0096] The following will use several embodiments as examples to describe in detail the bio-based succinic acid and its preparation method according to the present invention, but the bio-based succinic acid and its preparation method are not limited to these embodiments.

[0097] In the following detailed embodiments, all materials for which no preparation method is provided are commercially available chemicals.

[0098] Example 1

[0099] A bio-based succinic acid, the preparation method of which is as follows:

[0100] (1) The succinic acid fermentation broth with a concentration of 92 g / L was filtered through a ceramic membrane and treated by ion exchange to remove bacterial residue and impurities and inorganic salts. Then the resulting solution was concentrated by vacuum distillation at 82℃ to a bio-based succinic acid supersaturated solution with a succinic acid mass content of 33% and a pH value of 2.9.

[0101] (2) The supersaturated bio-based succinic acid solution obtained in step (1) was cooled from 82°C to 60°C at a rate of 0.5°C / min and a stirring speed of 50 rpm, and the stirring was stopped. The solution was then held at 60°C for 0.5 h to crystallize. Then the solution was cooled from 60°C to 40°C at a rate of 1°C / min and a stirring speed of 100 rpm, and the stirring was stopped. The solution was then held at 40°C for 0.5 h to crystallize. Finally, the solution was cooled from 40°C to 20°C at a rate of 2.5°C / min and a stirring speed of 200 rpm, and the stirring was stopped. The solution was then held at 20°C for 2 h to crystallize, thus obtaining a mixture.

[0102] (3) The mixture obtained in step (2) is subjected to solid-liquid separation, the solid is collected, the solid is washed with an ethanol aqueous solution (ethanol mass content is 66%), and then dried at 85°C to obtain the bio-based succinic acid, the specific information of which is shown in Table 1.

[0103] Example 2

[0104] A bio-based succinic acid, the preparation method of which is as follows:

[0105] (1) The succinic acid fermentation broth with a concentration of 88 g / L was filtered through a ceramic membrane and treated by ion exchange to remove bacterial residue and impurities and inorganic salts. Then the resulting solution was concentrated by vacuum distillation at 84℃ to a bio-based succinic acid supersaturated solution with a succinic acid mass content of 35% and a pH value of 2.7.

[0106] (2) The supersaturated bio-based succinic acid solution obtained in step (1) was cooled from 84°C to 55°C at a rate of 0.5°C / min and a stirring speed of 80 rpm, and the stirring was stopped. The solution was then held at 55°C for 1 h to crystallize. Then the solution was cooled from 55°C to 35°C at a rate of 1°C / min and a stirring speed of 150 rpm, and the stirring was stopped. The solution was then held at 35°C for 1 h to crystallize. Finally, the solution was cooled from 35°C to 10°C at a rate of 2°C / min and a stirring speed of 200 rpm, and the stirring was stopped. The solution was then held at 10°C for 1.5 h to crystallize, thus obtaining a mixture.

[0107] (3) The mixture obtained in step (2) is subjected to solid-liquid separation, the solid is collected, the solid is washed with an ethanol aqueous solution (ethanol mass content is 69%), and then dried at 88°C to obtain the bio-based succinic acid, the specific information of which is shown in Table 1.

[0108] Example 3

[0109] A bio-based succinic acid, the preparation method of which is as follows:

[0110] (1) The succinic acid fermentation broth with a concentration of 84 g / L was filtered through a ceramic membrane and treated by ion exchange to remove bacterial residue and impurities and inorganic salts. Then the resulting solution was concentrated by vacuum distillation at 83℃ to a bio-based succinic acid supersaturated solution with a succinic acid mass content of 36% and a pH value of 2.6.

[0111] (2) The supersaturated bio-based succinic acid solution obtained in step (1) was cooled from 83°C to 58°C at a rate of 0.5°C / min and a stirring speed of 60 rpm, and the stirring was stopped. The solution was then held at 58°C for 0.5 h to crystallize. Then the solution was cooled from 58°C to 35°C at a rate of 1°C / min and a stirring speed of 120 rpm, and the stirring was stopped. The solution was then held at 35°C for 1 h to crystallize. Finally, the solution was cooled from 35°C to 15°C at a rate of 3°C / min and a stirring speed of 150 rpm, and the stirring was stopped. The solution was then held at 15°C for 2 h to crystallize, thus obtaining a mixture.

[0112] (3) The mixture obtained in step (2) is subjected to solid-liquid separation, the solid is collected, the solid is washed with an ethanol aqueous solution (ethanol mass content is 72%), and then dried at 86°C to obtain the bio-based succinic acid, the specific information of which is shown in Table 1.

[0113] Example 4

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

[0115] (1) The succinic acid fermentation broth with a concentration of 95 g / L was filtered through a ceramic membrane and treated by ion exchange to remove bacterial residue and impurities and inorganic salts. Then the resulting solution was concentrated by vacuum distillation at 85 °C to a bio-based succinic acid supersaturated solution with a succinic acid mass content of 38% and a pH value of 2.1.

[0116] (2) The supersaturated bio-based succinic acid solution obtained in step (1) was cooled from 85°C to 58°C at a rate of 0.5°C / min and a stirring speed of 75 rpm, and the stirring was stopped. The solution was then held at 58°C for 1 h to crystallize. Then the solution was cooled from 58°C to 38°C at a rate of 1°C / min and a stirring speed of 135 rpm, and the stirring was stopped. The solution was then held at 38°C for 1 h to crystallize. Finally, the solution was cooled from 38°C to 18°C ​​at a rate of 2.5°C / min and a stirring speed of 180 rpm, and the stirring was stopped. The solution was then held at 18°C ​​for 2 h to crystallize, thus obtaining a mixture.

[0117] (3) The mixture obtained in step (2) is subjected to solid-liquid separation, the solid is collected, the solid is washed with an ethanol aqueous solution (ethanol mass content is 70%), and then dried at 90°C to obtain the bio-based succinic acid, the specific information of which is shown in Table 1.

[0118] Example 5

[0119] A bio-based succinic acid, the preparation method of which is as follows:

[0120] (1) The succinic acid fermentation broth with a concentration of 85 g / L was filtered through a ceramic membrane and treated by ion exchange to remove bacterial residue and impurities and inorganic salts. Then the resulting solution was concentrated by vacuum distillation at 82℃ to a bio-based succinic acid supersaturated solution with a succinic acid mass content of 35% and a pH value of 2.5.

[0121] (2) The supersaturated bio-based succinic acid solution obtained in step (1) was cooled from 82°C to 60°C at a rate of 0.5°C / min and a stirring speed of 60 rpm, and the stirring was stopped. The solution was then held at 60°C for 0.5 h to crystallize. Then the solution was cooled from 60°C to 40°C at a rate of 1°C / min and a stirring speed of 100 rpm, and the stirring was stopped. The solution was then held at 40°C for 0.5 h to crystallize. Finally, the solution was cooled from 40°C to 20°C at a rate of 2°C / min and a stirring speed of 160 rpm, and the stirring was stopped. The solution was then held at 20°C for 1.5 h to crystallize, thus obtaining a mixture.

[0122] (3) The mixture obtained in step (2) is subjected to solid-liquid separation, the solid is collected, the solid is washed with an ethanol aqueous solution (ethanol mass content is 65%), and then dried at 82°C to obtain the bio-based succinic acid, the specific information of which is shown in Table 1.

[0123] Example 6

[0124] A bio-based succinic acid, the preparation method of which is as follows:

[0125] (1) The succinic acid fermentation broth with a concentration of 88 g / L was filtered through a ceramic membrane and treated by ion exchange to remove bacterial residue and impurities and inorganic salts. Then the resulting solution was concentrated by vacuum distillation at 84℃ to a bio-based succinic acid supersaturated solution with a succinic acid mass content of 36% and a pH value of 2.3.

[0126] (2) The supersaturated bio-based succinic acid solution obtained in step (1) was cooled from 84°C to 55°C at a rate of 0.5°C / min and a stirring speed of 65 rpm, and the stirring was stopped. The solution was then held at 55°C for 1 h to crystallize. Then the solution was cooled from 55°C to 35°C at a rate of 1°C / min and a stirring speed of 110 rpm, and the stirring was stopped. The solution was then held at 35°C for 0.5 h to crystallize. Finally, the solution was cooled from 35°C to 15°C at a rate of 2°C / min and a stirring speed of 180 rpm, and the stirring was stopped. The solution was then held at 15°C for 1.5 h to crystallize, thus obtaining a mixture.

[0127] (3) The mixture obtained in step (2) is subjected to solid-liquid separation, the solid is collected, the solid is washed with an ethanol aqueous solution (ethanol mass content is 70%), and then dried at 85°C to obtain the bio-based succinic acid, the specific information of which is shown in Table 1.

[0128] Example 7

[0129] A bio-based succinic acid, the preparation method of which is as follows:

[0130] The bio-based succinic acid obtained in Comparative Example 3 was screened using sieves composed of 150 μm, 300 μm, and 500 μm to obtain bio-based succinic acid of different particle sizes. These bio-based succinic acids of different particle sizes were then mixed by weighing according to the proportions described in Table 1 to obtain the bio-based succinic acid.

[0131] Comparative Example 1

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

[0133] A bio-based succinic acid supersaturated solution with a succinic acid mass content of 33% was obtained using the same method as step (1) in Example 1. The solution was cooled from 82°C to 20°C at a rate of 1.5°C / min and a stirring speed of 100 rpm. The stirring was stopped, and the solution was crystallized at 20°C for 2 h to obtain a mixture. The mixture was subjected to solid-liquid separation, and the solid was collected. The solid was washed with an ethanol aqueous solution (ethanol mass content of 66%) and then dried thoroughly at 85°C to obtain the bio-based succinic acid. The specific information is shown in Table 1.

[0134] Comparative Example 2

[0135] A bio-based succinic acid, the preparation method of which is as follows:

[0136] A bio-based succinic acid supersaturated solution with a succinic acid mass content of 33% was obtained using the same method as step (1) in Example 1. The solution was cooled from 82°C to 60°C at a rate of 1°C / min and a stirring speed of 100 rpm, and the stirring was stopped. The solution was then held at 60°C for 0.5 h to crystallize. The solution was then cooled from 60°C to 40°C at a rate of 1°C / min and a stirring speed of 100 rpm, and the stirring was stopped. The solution was then held at 40°C for 0.5 h to crystallize. The solution was then cooled from 40°C to 20°C at a rate of 1°C / min and a stirring speed of 100 rpm, and the stirring was stopped. The solution was then held at 20°C for 2 h to crystallize, resulting in a mixture. The mixture was subjected to solid-liquid separation, and the solid was collected. The solid was washed with an ethanol aqueous solution (ethanol mass content of 66%) and then dried thoroughly at 85°C to obtain the bio-based succinic acid. The specific information is shown in Table 1.

[0137] Comparative Example 3

[0138] A bio-based succinic acid, the preparation method of which is as follows:

[0139] A bio-based succinic acid supersaturated solution with a succinic acid mass content of 33% was obtained using the same method as step (1) in Example 1. The solution was cooled from 82°C to 40°C at a rate of 1°C / min and a stirring speed of 100 rpm, and the stirring was stopped. The solution was then held at 40°C for 0.5 h to crystallize. The solution was then cooled from 40°C to 20°C at a rate of 2.5°C / min and a stirring speed of 200 rpm, and the stirring was stopped. The solution was held at 20°C for 2 h to crystallize, resulting in a mixture. The mixture was subjected to solid-liquid separation, and the solid was collected. The solid was washed with an ethanol aqueous solution (ethanol mass content of 66%) and then dried thoroughly at 85°C to obtain the bio-based succinic acid. The specific information is shown in Table 1.

[0140] Comparative Example 4

[0141] The specific information of commercially available bio-based succinic acid (Shandong Landian Biotechnology Co., Ltd., bio-based succinic acid) is shown in Table 1.

[0142] Comparative Example 5

[0143] A bio-based succinic acid, the preparation method of which is as follows:

[0144] The bio-based succinic acid obtained in Comparative Example 3 was screened using sieves composed of 150μm, 300μm, and 500μm to obtain bio-based succinic acid with different particle sizes. These bio-based succinic acids with different particle sizes were then mixed in proportion by weighing to obtain the bio-based succinic acid shown in Table 1.

[0145] Comparative Example 6

[0146] A bio-based succinic acid, the preparation method of which is as follows:

[0147] The bio-based succinic acid obtained in Comparative Example 3 was screened using sieves composed of 150μm, 300μm, and 500μm to obtain bio-based succinic acid with different particle sizes. These bio-based succinic acids with different particle sizes were then mixed in proportion by weighing to obtain the bio-based succinic acid shown in Table 1.

[0148] Table 1

[0149]

[0150] As can be seen from the data in Table 1, the bio-based succinic acid provided by this invention has a D... 50 The particle component has a particle size of 300-500 μm and a specific particle size distribution. The particle size distribution is controllable and the particle size uniformity is good. It can reduce the adhesion between particles and make the agglomeration strength as low as 11-17 N, avoiding agglomeration and clumping problems. This extends the storage time of bio-based succinic acid, improves storage performance, and is more suitable for downstream applications.

[0151] The bio-based succinic acid in Comparative Examples 1-4 does not have the particle size distribution characteristics defined in this invention, and its agglomeration strength is 22-58N. It is prone to agglomeration problems, which leads to a shorter storage time and increases the difficulty of downstream applications.

[0152] The median particle size of the bio-based succinic acid in Comparative Example 6 was in the range of 300-500 μm, but the content of particles with particle size d1, d2, d3, and d4 was outside this range, and the agglomeration strength was improved.

[0153] The application of the bio-based succinic acid described in this invention will be detailed below using application examples, but the application of the bio-based succinic acid is not limited to these application examples.

[0154] Application examples

[0155] A bath salt comprises a bath salt matrix (commercially available sea salt with a particle size of 0.5 mm) in a mass ratio of 9:1 and bio-based succinic acid, wherein the bio-based succinic acid is derived from Examples 1-7 and Comparative Examples 1-6.

[0156] The bath salt is prepared as follows: the bath salt matrix is ​​mixed with bio-based succinic acid, stirred evenly, and then passed through a 20-mesh sieve to obtain the bath salt.

[0157] The coefficient of friction of bath salts was tested using the following method:

[0158] A 200 g bath salt sample was spread evenly on a test plate, which was then placed on a CMXD-01 friction coefficient tester. A sample loading block (mass 500 g, contact area 25 cm²) was used. 2The sample is uniformly pressed onto the sample surface, with a preloading time of 30 seconds.

[0159] Static friction test: The plate is slowly pulled at a speed of 0.5 mm / s, and the maximum pulling force (F) when the sample begins to slide is recorded. max ), static friction coefficient u s The calculation formula is: u s = F max / N0; where N0 represents the weight of the loaded block, N0=4.9 N.

[0160] Dynamic friction test: After sliding, maintain a speed of 10 mm / s and record the average tension (F) during the steady-state phase (sliding distance 10-20 mm). avg ), coefficient of kinetic friction u k The calculation formula is: u k = F avg / N0, N0=4.9 N.

[0161] The test data is shown in Table 2:

[0162] Table 2

[0163]

[0164] According to the test data in Table 2, the bio-based succinic acid provided by this invention, when used to prepare bath salts, can provide more suitable friction due to its larger particle size and specific particle size distribution characteristics, thus improving the static friction coefficient u of the bath salts. s The coefficient of kinetic friction is 0.27-0.32. k The concentration is 0.45-0.52, which improves the comfort, gentleness and absorption of bath salts, and enhances the cleaning efficiency with the same amount, while avoiding the drawbacks of bath salts irritating the skin.

[0165] The static friction coefficient u of the bath salts using bio-based succinic acid in comparative examples 1-4 and 6 s The coefficient of kinetic friction is 0.22-0.25. k With a coefficient of friction of 0.35-0.39, bath salts offer a lower user experience.

[0166] The static friction coefficient u of the bath salt using bio-based succinic acid (Comparative Example 5) s The coefficient of kinetic friction is 0.36, u. k With a coefficient of friction of 0.61, bath salts may irritate the skin, thus diminishing the user experience.

[0167] The applicant declares that this invention illustrates the bio-based succinic acid, its preparation method, and its application 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 for the product, addition 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, characterized in that, The median particle size of the bio-based succinic acid is 300-500 μm, and the bio-based succinic acid comprises particles of the following particle sizes by mass percentage: Particles with a diameter of d1 account for 0-10%; Particles with a diameter of d2 account for 30-40%; Particles with a diameter of d3 account for 40-50%; Particles with a diameter of d4 account for 8-18%; Among them, d1<150 μm, 150 μm≤d2<300 μm, 300 μm≤d3<500 μm, d4≥500 μm.

2. The bio-based succinic acid according to claim 1, characterized in that, The median particle size of the bio-based succinic acid is 320-400 μm.

3. The bio-based succinic acid according to claim 1, characterized in that, The bio-based succinic acid comprises particles of the following particle sizes by weight percentage: Particles with a diameter of d1 account for 3-9%; Particles with a diameter of d2 account for 31.5-35.5%; Particles with a diameter of d3 account for 44.5-49.5%; Particles with a diameter of d4 account for 9.5-15.5%.

4. A method for preparing bio-based succinic acid as described in any one of claims 1-3, characterized in that, The preparation method includes the following steps: The bio-based succinic acid supersaturated solution was cooled from temperature T1 to temperature T2 at a rate v1 to carry out the first holding temperature crystallization; then cooled from temperature T2 to temperature T3 at a rate v2 to carry out the second holding temperature crystallization; and then cooled from temperature T3 to temperature T4 at a rate v3 to carry out the third holding temperature crystallization to obtain a mixture. The mixture was subjected to solid-liquid separation, and the solid was collected to obtain the bio-based succinic acid; Among them, T1≥78℃, 50℃≤T2≤62℃, 30℃≤T3≤42℃, T4≤22℃; v1≤0.8℃ / min, and v1<v2≤v3.

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 pH value of the bio-based succinic acid supersaturated solution is 2-3.

6. The preparation method according to claim 4, characterized in that, 0.2℃ / min≤v1≤0.7℃ / min; 0.8℃ / min<v2≤1.5℃ / min; 1.8℃ / min≤v3≤3.2℃ / min; The cooling is carried out under stirring conditions; The stirring speed during the cooling at rate v1 is 40-90 rpm; The stirring speed during the cooling rate v2 is 95-155 rpm; The stirring speed during the cooling at rate v3 is 140-300 rpm; The first holding time for crystallization is 0.4-1.5 h; The second holding time for crystallization is 0.4-1.5 h; The third holding time for crystallization is 1-3 hours.

7. The preparation method according to claim 4, characterized in that, The solid-liquid separation method includes centrifugation, filtration, or membrane separation; The process of collecting solids also includes washing and drying steps; The washing reagent used for the washing includes an alcohol-water mixture; The drying temperature is 80-100℃.

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

9. A bath salt, characterized in that, The bath salts comprise a bath salt matrix and bio-based succinic acid as described in any one of claims 1-3.

10. The bath salt according to claim 9, characterized in that, The bath salt contains 0.1-15% bio-based succinic acid by mass.

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