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

Abstract

The invention provides bio-based succinic acid as well as a preparation method and application thereof. The bio-based succinic acid comprises succinic acid, an N element, an S element and a P element, in the bio-based succinic acid, the mass content of an element N is 0.1-10 ppm, the mass content of an element S is 0.1-3 ppm, and the mass content of an element P is 0.1-10 ppm. The bio-based succinic acid provided by the invention contains N, S and P elements with specific contents, and the succinic acid is high in purity and low in impurity content. The bio-based succinic acid is applied to synthesis of chemical products such as polyester, 1, 4-butanediol, succinic anhydride, gamma-butyrolactone and tetrahydrofuran, side reactions can be effectively inhibited, target products with high yield and high purity are obtained, and the products have better hue and physical properties.

Description

Technical Field

[0001] The present invention belongs to the technical field of biochemistry, and particularly relates to a bio-based succinic acid, a preparation method thereof, and an application thereof. Background Art

[0002] Succinic acid is an excellent platform compound and has wide applications in the fields of chemical engineering, materials, medicine, and food. It is a raw material for the biodegradable material PBS (polybutylene succinate). There are mainly two methods for preparing succinic acid. One is the traditional chemical synthesis method, such as catalytic reduction of maleic acid to obtain succinic acid, hydrolysis of succinonitrile to prepare succinic acid, etc.; the other is the microbial fermentation method. The traditional chemical synthesis method is affected by the price of petroleum, and the cost remains high. At the same time, its manufacturing process does not conform to the strategic goal of carbon reduction in today's society. Therefore, in recent years, there has been a trend of being gradually replaced by the microbial fermentation method. The microbial fermentation method uses renewable biomass resources as raw materials, with a green production process and resource conservation. Bio-based succinic acid is listed by the United States as one of the 12 most valuable platform compounds in the future and has attracted much attention in the industry.

[0003] The process of preparing succinic acid by microbial fermentation includes two stages. The first stage is to ferment using specific microorganisms to obtain a succinic acid fermentation broth. The second stage is to treat the succinic acid fermentation broth by some physical and chemical methods to separate succinic acid from impurities and obtain the target product succinic acid. The process of preparing succinic acid by microbial fermentation is mainly carried out under neutral conditions. However, due to the continuous production of the product succinic acid, the pH value of the fermentation system continues to decrease, which is not conducive to the growth of the strain and causes a decrease in the utilization rate of the carbon source. In order to maintain the stability of the pH value of the fermentation system, an alkaline substance (such as ammonia water, sodium hydroxide, etc.) is added during the fermentation process for neutralization to convert succinic acid into succinate. The succinate needs to be acidified with acid again in the purification stage. This process not only consumes a large amount of acid and alkali, but also introduces more impurities, increasing the difficulty of extracting succinic acid from the fermentation broth.

[0004] In order to separate succinic acid from impurities in the fermentation broth, the industry usually adopts a treatment method combining multiple purification means. For example, CN1887843A discloses a method for separating and extracting succinic acid from an anaerobic fermentation broth. The fermentation broth is filtered through a microfiltration membrane, then through an ultrafiltration membrane, and then decolorized and purified with activated carbon to obtain a clarified succinic acid solution; the succinic acid solution is concentrated and crystallized to obtain a succinic acid product. CN101811953A discloses a method for extracting and separating succinic acid from a fermentation broth, including ultrafiltration separation, ion exchange with an H-type strongly acidic cation exchange resin, decolorization, concentration, crystallization, centrifugation, washing, and drying in sequence to obtain succinic acid.

[0005] At present, the methods for extracting and purifying succinic acid from fermentation broth mainly focus on filtration, membrane separation, ion exchange, decolorization, crystallization, etc., but the purification effect is still not ideal. Specifically, the large amount of acids and bases added during the fermentation process and the residual nutrients in the culture medium make the succinic acid product contain a large amount of elements such as N, S, and P. The existing purification processes cannot effectively remove the aforementioned elements, resulting in the presence of impurity elements in the succinic acid product, which has a greater impact on the subsequent processing of succinic acid. Therefore, how to obtain biobased succinic acid with low impurity element content and high purity is the research focus in this field. Summary of the Invention

[0006] Aiming at the deficiencies of the prior art, the purpose of the present invention is to provide a biobased succinic acid, its preparation method and application. The biobased succinic acid has high purity and low contents of N, S, and P elements. When it is applied to the synthesis of five-membered heterocyclic compounds and polyesters, it can effectively inhibit side reactions and improve the hue and physical properties of the products.

[0007] To achieve this purpose, the present invention adopts the following technical solutions:

[0008] In the first aspect, the present invention provides a biobased succinic acid, which includes succinic acid (pure substance), N element, S element, and P element; the mass content of N element in the biobased succinic acid is 0.1 - 10 ppm, the mass content of S element is 0.1 - 3 ppm, and the mass content of P element is 0.1 - 10 ppm.

[0009] The biobased succinic acid provided by the present invention contains specific contents of N, S, and P elements, and has the excellent qualities of high purity of succinic acid and low impurity content. The biobased succinic acid can effectively inhibit side reactions in the synthesis of polyesters, 1,4-butanediol, and five-membered heterocyclic compounds, obtain target products with high yields and high purities, and improve the hue and physical properties of the products.

[0010] The following are the preferred technical solutions of the present invention, but they do not limit the technical solutions provided by the present invention. Through the following preferred technical solutions, the purpose and beneficial effects of the present invention can be better achieved.

[0011] In the present invention, the term "ppm" represents parts per million, and 1 ppm represents one in a million.

[0012] Exemplarily, the N element in the biobased succinic acid is tested by the Kjeldahl method and a Kjeldahl nitrogen analyzer; the S element content is tested by a sulfur element analyzer (such as the ZDL-YE100D fully automatic sulfur analyzer); the P element content is tested by the phosphomolybdic acid colorimetric method.

[0013] It should be noted that the testing methods for the mass contents of N, S, and P elements in the bio-based succinic acid are not limited to those listed above. In the present invention, the lower limits of the mass contents of N, S, and P elements are restricted by the detection means.

[0014] Specifically, the mass content of N element in the bio-based succinic acid is 0.1 - 10 ppm. For example, it can be 0.15 ppm, 0.3 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 1.5 ppm, 2 ppm, 2.5 ppm, 3 ppm, 3.5 ppm, 4 ppm, 4.5 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, and the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.2 - 8.5 ppm, and more preferably 1.0 - 2.2 ppm.

[0015] The mass content of S element in the bio-based succinic acid is 0.1 - 3 ppm. For example, it can be 0.15 ppm, 0.3 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 1.5 ppm, 2 ppm, 2.5 ppm, or 2.8 ppm, and the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.2 - 1.5 ppm, and more preferably 0.3 - 0.7 ppm.

[0016] The mass content of P element in the bio-based succinic acid is 0.1 - 10 ppm. For example, it can be 0.15 ppm, 0.3 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 1.5 ppm, 2 ppm, 2.5 ppm, 3 ppm, 3.5 ppm, 4 ppm, 4.5 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, and the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.2 - 6.5 ppm, and more preferably 0.7 - 2.3 ppm.

[0017] Preferably, the mass content (purity) of succinic acid in the bio-based succinic acid ≥ 99.7%. For example, it can be 99.72%, 99.75%, 99.78%, 99.8%, 99.82%, 99.85%, 99.88%, or 99.9%, and the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 99.75 - 99.88%.

[0018] Preferably, the yellow index (YI) of the bio - based succinic acid is 0.01 - 1.0. For example, it can be 0.02, 0.05, 0.08, 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9 or 0.95, as well as specific point values between the above - mentioned point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. More preferably, it is 0.2 - 0.9, and further preferably 0.2 - 0.7.

[0019] Exemplarily, the yellow index of the bio - based succinic acid can be tested by the method in Standard GB / T 39822 - 2021. Specifically, the bio - based succinic acid to be tested is placed in a cylindrical container made of transparent glass or quartz glass, and tested with a yellow index meter, with the light source being the CIE standard D65 light source.

[0020] Preferably, the bio - based succinic acid also includes water and / or heavy metals.

[0021] Preferably, the mass content of water in the bio - based succinic acid is 0.1 - 4000 ppm. For example, it can be 1 ppm, 5 ppm, 10 ppm, 20 ppm, 30 ppm, 50 ppm, 80 ppm, 100 ppm, 150 ppm, 200 ppm, 250 ppm, 300 ppm, 500 ppm, 800 ppm, 1000 ppm, 1200 ppm, 1500 ppm, 1800 ppm, 2000 ppm, 2200 ppm, 2500 ppm, 2800 ppm, 3000 ppm, 3200 ppm, 3500 ppm or 3800 ppm, as well as specific point values between the above - mentioned point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 1 - 700 ppm, and more preferably 380 - 520 ppm.

[0022] The term "heavy metal" refers to a metal with a density > 4.5 g / cm 3 such as lead, mercury, copper; the heavy metal in the bio - based succinic acid described in the present invention is mainly lead (Pb).

[0023] Preferably, the mass content of heavy metals in the bio-based succinic acid is 0.01 - 10 ppm, for example, it can be 0.015 ppm, 0.03 ppm, 0.05 ppm, 0.08 ppm, 0.1 ppm, 0.2 ppm, 0.5 ppm, 0.8 ppm, 1 ppm, 2 ppm, 3 ppm, 3.5 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm or 9 ppm, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 0.02 - 3 ppm, and more preferably 0.02 - 1 ppm.

[0024] Preferably, the melting point of the bio-based succinic acid is 185 - 188 °C, for example, it can be 185.5 °C, 186 °C, 186.5 °C, 187 °C or 187.5 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0025] Preferably, the content of ignition residue in the bio-based succinic acid is 10 - 100 ppm, for example, it can be 12 ppm, 15 ppm, 20 ppm, 25 ppm, 30 ppm, 35 ppm, 40 ppm, 45 ppm, 50 ppm, 55 ppm, 60 ppm, 65 ppm, 70 ppm, 75 ppm, 80 ppm, 85 ppm, 90 ppm or 95 ppm, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 60 - 88 ppm.

[0026] Exemplarily, the content (purity), melting point, ignition residue content, water content, and heavy metal content of succinic acid in the bio-based succinic acid can be obtained by testing according to the method in GB / T 34686 - 2017.

[0027] In a second aspect, the present invention provides a method for preparing the bio-based succinic acid as described in the first aspect, and the preparation method includes:

[0028] Inoculating the seed liquid of the succinic acid-producing strain into a culture medium, and successively performing aerobic fermentation and anaerobic fermentation to obtain a fermentation broth;

[0029] Filtering the fermentation broth to obtain a filtrate;

[0030] Performing at least 4 ion exchange treatments on the filtrate to obtain a permeate;

[0031] The permeate is decolorized, concentrated, and crystallized to obtain the bio-based succinic acid.

[0032] The preparation method provided by the present invention uses renewable biomass resources as raw materials, obtains a fermentation broth containing succinic acid through microbial fermentation, and then designs a purification method including filtration, multiple (≥4 times) ion exchange treatments, decolorization, concentration, and crystallization to separate impurities from succinic acid and obtain the bio-based succinic acid containing specific contents of N, S, and P elements, with high purity and ultra-low impurity content.

[0033] Preferably, the succinic acid-producing strain includes Escherichia coli, Actinobacillus succinogenes, or Anaerobiospirillum.

[0034] Preferably, the inoculation amount of the seed liquid is 1-10%, for example, it can be 2%, 3%, 4%, 5%, 6%, 7%, 8%, or 9%, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0035] In the present invention, the term "inoculation amount" refers to the volume percentage of the seed liquid relative to the culture medium.

[0036] Preferably, the culture medium includes the following components: glucose 80-150 g / L, yeast powder 10-30 g / L, urea 5-20 g / L, dipotassium hydrogen phosphate 5-10 g / L, potassium dihydrogen phosphate 5-10 g / L, magnesium sulfate 0.1-2 g / L, and vitamins 0.1-2 g / L.

[0037] Specifically, the concentration of glucose in the culture medium is 80-150 g / L, for example, it can be 85 g / L, 90 g / L, 95 g / L, 100 g / L, 105 g / L, 110 g / L, 115 g / L, 120 g / L, 125 g / L, 130 g / L, 135 g / L, 140 g / L, or 145 g / L, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0038] The concentration of yeast powder in the culture medium is 10-30 g / L, for example, it can be 12 g / L, 15 g / L, 18 g / L, 20 g / L, 22 g / L, 25 g / L, or 28 g / L, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0039] The concentration of urea in the culture medium is 5-20 g / L, for example, it can be 6 g / L, 8 g / L, 10 g / L, 12 g / L, 14 g / L, 15 g / L, 16 g / L, or 18 g / L, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0040] The concentration of dipotassium hydrogen phosphate in the culture medium is 5-10 g / L. For example, it can be 5.5 g / L, 6 g / L, 6.5 g / L, 7 g / L, 7.5 g / L, 8 g / L, 8.5 g / L, 9 g / L or 9.5 g / L, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0041] The concentration of potassium dihydrogen phosphate in the culture medium is 5-10 g / L. For example, it can be 5.5 g / L, 6 g / L, 6.5 g / L, 7 g / L, 7.5 g / L, 8 g / L, 8.5 g / L, 9 g / L or 9.5 g / L, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0042] The concentration of magnesium sulfate in the culture medium is 0.1-2 g / L. For example, it can be 0.2 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, 0.8 g / L, 1 g / L, 1.2 g / L, 1.5 g / L, 1.6 g / L or 1.8 g / L, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0043] The concentration of vitamins in the culture medium is 0.1-2 g / L. For example, it can be 0.2 g / L, 0.4 g / L, 0.5 g / L, 0.6 g / L, 0.8 g / L, 1 g / L, 1.2 g / L, 1.5 g / L, 1.6 g / L or 1.8 g / L, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0044] Preferably, the vitamins include any one or a combination of at least two of vitamin B1, vitamin B2, and vitamin B3.

[0045] Preferably, the pH value of the aerobic fermentation is 6.5-7.5. For example, it can be 6.6, 6.7, 6.8, 6.9, 7.0, 7.2 or 7.4, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range. Further preferably, it is 6.6-7.0.

[0046] As a preferred technical solution of the present invention, an alkaline neutralizing agent is added to the system during the aerobic fermentation to make the pH value of the aerobic fermentation 6.5-7.5.

[0047] Preferably, the alkaline neutralizing agent includes any one or a combination of at least two of sodium hydroxide, sodium carbonate, magnesium carbonate, magnesium chloride, calcium carbonate, and calcium chloride.

[0048] Preferably, the aeration rate of the aerobic fermentation is 1 - 5 vvm. For example, it can be 1.5 vvm, 2 vvm, 2.5 vvm, 3 vvm, 3.5 vvm, 4 vvm, or 4.5 vvm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0049] Among them, "vvm" represents the ratio of the volume of gas passed per minute to the actual volume of the liquid material in the fermentation tank; it can also be understood as the volume of air required per cubic meter of fermentation broth per minute.

[0050] Preferably, the aerobic fermentation is carried out under stirring conditions.

[0051] Preferably, the stirring speed of the aerobic fermentation is 150 - 500 rpm. For example, it can be 180 rpm, 200 rpm, 220 rpm, 250 rpm, 280 rpm, 300 rpm, 320 rpm, 350 rpm, 380 rpm, 400 rpm, 420 rpm, 450 rpm, or 480 rpm, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range. Further preferably, it is 200 - 300 rpm.

[0052] Preferably, the temperature of the aerobic fermentation is 30 - 35 °C. For example, it can be 30.5 °C, 31 °C, 31.5 °C, 32 °C, 32.5 °C, 33 °C, 33.5 °C, 34 °C, or 34.5 °C, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0053] Preferably, the time of the aerobic fermentation is 8 - 12 h. For example, it can be 8.5 h, 9 h, 9.5 h, 10 h, 10.5 h, 11 h, or 11.5 h, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0054] Preferably, the pH value of the anaerobic fermentation is 5.5 - 6.5. For example, it can be 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3, or 6.4, as well as specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the range.

[0055] As a preferred technical solution of the present invention, an alkaline neutralizing agent is added to the system during the anaerobic fermentation so that the pH value of the anaerobic fermentation is 5.5 - 6.5.

[0056] Preferably, the alkaline neutralizing agent includes any one or a combination of at least two of sodium hydroxide, sodium carbonate, magnesium carbonate, magnesium chloride, calcium carbonate, and calcium chloride.

[0057] Preferably, the stirring speed of the anaerobic fermentation is 200 - 350 rpm. For example, it can be 220 rpm, 250 rpm, 280 rpm, 300 rpm, 320 rpm, or 340 rpm, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0058] Preferably, the temperature of the anaerobic fermentation is 33 - 40 °C. For example, it can be 34 °C, 35 °C, 36 °C, 37 °C, 38 °C, or 39 °C, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0059] Preferably, the time of the anaerobic fermentation is 36 - 48 h. For example, it can be 38 h, 40 h, 41 h, 42 h, 43 h, 44 h, 45 h, 46 h, or 47 h, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0060] Preferably, the filtration method includes any one or a combination of at least two of microfiltration, nanofiltration, ultrafiltration, or reverse osmosis, and nanofiltration is further preferred.

[0061] Preferably, the temperature of the filtration is 40 - 60 °C. For example, it can be 42 °C, 45 °C, 48 °C, 50 °C, 52 °C, 55 °C, or 58 °C, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0062] Preferably, the concentration multiple of the filtration is 10 - 40 times. For example, it can be 12 times, 15 times, 18 times, 20 times, 22 times, 25 times, 28 times, 30 times, 32 times, 35 times, or 38 times, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0063] In the preparation method of the present invention, the filtrate is subjected to at least 4 ion exchange treatments. For example, the number of ion exchange treatments is 4 times, 5 times, 6 times, 7 times, 8 times, etc.; considering production efficiency and cost, 4 - 6 times are preferred, and 4 times are more preferred.

[0064] Preferably, the ion exchange treatment includes at least 2 times (such as 2 times, 3 times, 4 times, etc.) of cation exchange and at least 2 times (such as 2 times, 3 times, 4 times, etc.) of anion exchange.

[0065] Preferably, before each cation exchange, the pH value of the solution to be treated is adjusted to 5.5 - 6.5, for example, it can be 5.6, 5.7, 5.8, 5.9, 6.0, 6.1, 6.2, 6.3 or 6.4, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0066] Preferably, before each anion exchange, the pH value of the solution to be treated is adjusted to 7.0 - 8.0, for example, it can be 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8 or 7.9, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0067] As a preferred technical solution of the present invention, adjusting the pH value of the solution to be treated to 5.5 - 6.5 before cation exchange and adjusting the pH value of the solution to be treated to 7.0 - 8.0 before anion exchange can effectively improve the impurity removal effect of ion exchange and achieve more thorough removal of N, P, and S elements.

[0068] Preferably, the temperature of the ion exchange treatment is 30 - 55 °C, for example, it can be 32 °C, 35 °C, 38 °C, 40 °C, 42 °C, 45 °C, 48 °C, 50 °C, 52 °C or 54 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0069] Preferably, the residence time of each ion exchange is independently 15 - 120 min, for example, it can be 20 min, 30 min, 40 min, 60 min, 80 min, 100 min or 110 min, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the above range.

[0070] As a preferred technical solution of the present invention, the at least 2 times of cation exchange includes the first cation exchange and the second cation exchange. The resin for the first cation exchange includes macroporous strong acid cation exchange resin, which can remove Na + , NH4 +and cation impurities; the second cation exchange resin includes a homogeneous strong acid cation exchange resin, which can specifically remove free ammonia and ammonium ions, and further reduce the N element content. The at least two anion exchanges include a first anion exchange and a second anion exchange. The resin for the first anion exchange includes a macroporous weak base anion exchange resin, which can remove sulfate and reduce the S element content; the resin for the second anion exchange includes a macroporous polystyrene anion exchange resin, which can remove various valences of phosphorus in water (such as orthophosphate, hypophosphite, etc.), thereby controlling the P element content. The present invention achieves a better impurity removal effect through at least four ion exchanges, and obtains the bio-based succinic acid containing specific contents of N, S, and P elements.

[0071] It should be noted that the present invention does not impose special restrictions on the order of at least four ion exchanges, and those skilled in the art can adjust it according to the process requirements. Considering production efficiency, it can be carried out in sequence according to the order of the first cation exchange, the second cation exchange, the first anion exchange, and the second anion exchange, or it can also be carried out in sequence according to the order of the first cation exchange, the first anion exchange, the second cation exchange, and the second anion exchange.

[0072] Preferably, the residence time of the first cation exchange is 20 - 60 min, for example, it can be 25 min, 30 min, 35 min, 40 min, 45 min, 50 min, or 55 min, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0073] Preferably, the residence time of the second cation exchange is 10 - 40 min, for example, it can be 15 min, 20 min, 25 min, 30 min, or 35 min, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0074] Preferably, the residence time of the first anion exchange is 40 - 120 min, for example, it can be 50 min, 60 min, 70 min, 80 min, 90 min, 100 min, or 110 min, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0075] Preferably, the residence time of the second anion exchange is 10 - 40 min, for example, it can be 15 min, 20 min, 25 min, 30 min, or 35 min, as well as specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the above range.

[0076] Preferably, the decolorizing agent used for decolorization includes any one or a combination of at least two of activated carbon, clay, and adsorption resin, and activated carbon is further preferred.

[0077] Preferably, the activated carbon includes granular activated carbon and / or powdered activated carbon.

[0078] Optionally, the packing density of the granular activated carbon is 0.4 - 0.5 g / cm 3 ; the particle size of the powdered activated carbon is 0.2 - 0.5 mm.

[0079] Preferably, the method of decolorization includes: passing the permeate through a decolorization column filled with a decolorizing agent for decolorization treatment.

[0080] Preferably, the temperature of decolorization is 30 - 60 °C, for example, it can be 32 °C, 35 °C, 38 °C, 40 °C, 42 °C, 45 °C, 48 °C, 50 °C, 51 °C, 52 °C, 53 °C, 54 °C, 55 °C, 56 °C, 57 °C, 58 °C or 59 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0081] Exemplarily, the temperature of decolorization can be controlled by installing a jacket for heat tracing on the outer wall of the decolorization column.

[0082] Preferably, the time of decolorization is 10 - 60 min, for example, it can be 15 min, 20 min, 25 min, 30 min, 32 min, 35 min, 38 min, 40 min, 42 min, 45 min, 48 min, 50 min, 52 min, 55 min or 58 min, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0083] Preferably, the temperature of concentration is 60 - 80 °C, for example, it can be 62 °C, 65 °C, 68 °C, 70 °C, 72 °C, 75 °C or 78 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0084] Preferably, the system pressure of concentration is 10 - 40 kPa, for example, it can be 12 kPa, 15 kPa, 18 kPa, 20 kPa, 22 kPa, 25 kPa, 28 kPa, 30 kPa, 32 kPa, 35 kPa or 38 kPa, as well as the specific point values between the above point values. Due to space limitations and for the sake of brevity, the present invention does not exhaustively list the specific point values included in the range.

[0085] Preferably, the concentration multiple is 2 - 10 times, for example, it can be 2.5 times, 3 times, 3.5 times, 4 times, 4.5 times, 5 times, 5.5 times, 6 times, 6.5 times, 7 times, 7.5 times, 8 times, 8.5 times, 9 times or 9.5 times, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0086] Preferably, the crystallization temperature is 10 - 30 °C, for example, it can be 12 °C, 15 °C, 18 °C, 20 °C, 22 °C, 25 °C or 28 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0087] Preferably, the system pressure for crystallization is 60 - 80 kPa, for example, it can be 62 kPa, 65 kPa, 68 kPa, 70 kPa, 72 kPa, 75 kPa or 78 kPa, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0088] Preferably, after crystallization, a drying step is further included.

[0089] Preferably, the drying temperature is 75 - 85 °C, for example, it can be 76 °C, 78 °C, 80 °C, 82 °C or 84 °C, as well as the specific point values between the above point values. Due to space limitations and for the sake of simplicity, the present invention does not exhaustively list the specific point values included in the said range.

[0090] Preferably, after crystallization, a recrystallization step is further included.

[0091] In a preferred technical solution, the preparation method of the bio - based succinic acid includes the following steps:

[0092] (1) Inoculate the seed liquid of the succinic acid - producing strain into the culture medium at an inoculation amount of 1 - 10%, and perform aerobic fermentation and anaerobic fermentation in sequence to obtain a fermentation broth;

[0093] Among them, the culture medium includes the following components: glucose 80 - 150 g / L, yeast powder 10 - 30 g / L, urea 5 - 20 g / L, dipotassium hydrogen phosphate 5 - 10 g / L, potassium dihydrogen phosphate 5 - 10 g / L, magnesium sulfate 0.1 - 2 g / L, vitamin 0.1 - 2 g / L;

[0094] The parameters of the aerobic fermentation include: pH value is 6.5 - 7.0, aeration rate is 1 - 5 vvm, stirring speed is 200 - 500 rpm, temperature is 30 - 35 °C, and time is 8 - 12 h;

[0095] The parameters of the anaerobic fermentation include: the pH value is 5.5 - 6.5, the stirring speed is 200 - 350 rpm, the temperature is 33 - 40 °C, and the time is 36 - 48 h;

[0096] (2) Filter the fermentation broth at 40 - 60 °C to obtain a filtrate;

[0097] (3) Perform ion exchange treatment on the filtrate to obtain a permeate;

[0098] The temperature of the ion exchange treatment is 30 - 50 °C, and it includes the first cation exchange, the second cation exchange, the first anion exchange, and the second anion exchange; before the first cation exchange and the second cation exchange, adjust the pH value of the solution to be treated to 5.5 - 6.5; the resin for the first cation exchange includes macroporous strong acid cation exchange resin, and the residence time is 20 - 60 min; the resin for the second cation exchange includes macroporous strong acid cation exchange resin, and the residence time is 10 - 40 min; before the first anion exchange and the second anion exchange, adjust the pH value of the solution to be treated to 7.0 - 8.0; the resin for the first anion exchange includes macroporous weak base anion exchange resin, and the residence time is 40 - 120 min; the resin for the second anion exchange includes macroporous polystyrene anion exchange resin, and the residence time is 10 - 40 min;

[0099] (4) The permeate is subjected to decolorization, concentration, crystallization, and recrystallization to obtain the bio - based succinic acid;

[0100] Among them, the temperature of the decolorization is 50 - 60 °C, and the time is 30 - 60 min,

[0101] The temperature of the concentration is 60 - 80 °C, the system pressure is 10 - 40 kPa, and the concentration multiple is 2 - 10 times;

[0102] The temperature of the crystallization is 10 - 30 °C, and the system pressure is 60 - 80 kPa.

[0103] 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 by the present invention. Exemplarily, the fermentation broth can be purified by a combination of ultrafiltration, multiple extractions, decolorization, electrodialysis, multiple recrystallizations, etc. to obtain bio - based succinic acid with low impurity content.

[0104] In the third aspect, the present invention provides an application of the bio - based succinic acid as described in the first aspect in the preparation of 1,4 - butanediol, five - membered heterocyclic compounds, or polyesters.

[0105] Preferably, the five-membered heterocyclic compound includes succinic anhydride, γ-butyrolactone or tetrahydrofuran.

[0106] Preferably, the polyester includes polybutylene succinate (PBS) or alkyd resin.

[0107] Compared with the prior art, the present invention has the following beneficial effects:

[0108] The bio-based succinic acid provided by the present invention contains specific contents of N, S and P elements, and the succinic acid has high purity and low impurity content. The bio-based succinic acid is used in the synthesis of chemical products such as polyester, 1,4-butanediol, succinic anhydride, γ-butyrolactone, tetrahydrofuran, etc., can effectively inhibit side reactions, obtain target products with high yield and high purity, and make the products have better hue and physical properties. Detailed Embodiments

[0109] The technical solutions of the present invention will be further described below through specific embodiments. Those skilled in the art should understand that the embodiments are only for helping to understand the present invention and should not be regarded as specific limitations on the present invention.

[0110] As used herein, the terms "comprising", "including", "having", "containing" or any other variation thereof are intended to cover non-exclusive inclusion. For example, a composition, step, method, article or apparatus containing the listed elements is not necessarily limited to those elements, but may also include other elements not expressly listed or elements inherent to such composition, step, method, article or apparatus.

[0111] In the following specific embodiments of the present invention, each component for preparing the culture medium and various reagents for the purification treatment of the filtrate are commercially available chemicals; the succinic acid-producing strain is commercially available Actinobacillus succinogenes. The cation exchange resin is a commercially available macroporous strong acid cation exchange resin (such as any one of D001 type, C100EDL type, IRC200Na type), a commercially available uniform particle strong acid cation exchange resin (such as Tulsimer T-42 or Tulsion T-42H); the anion exchange resin is a commercially available macroporous weak base anion exchange resin (such as any one of D301 type, D354 type, D370 type), a commercially available macroporous polystyrene anion exchange resin (such as LSC-770, A-107).

[0112] The specific information of some materials is as follows:

[0113] (1) Seed culture medium, the components are as follows: glucose 20 g / L, yeast extract 10 g / L, corn steep liquor dry powder 5 g / L, NaHCO3 2 g / L, NaH2PO4 2 g / L, K2HPO4 2 g / L, and the solvent is water.

[0114] (2) Fermentation medium, with the following components: glucose 120 g / L, yeast powder 30 g / L, urea 8 g / L, dipotassium hydrogen phosphate 8 g / L, potassium dihydrogen phosphate 8 g / L, magnesium sulfate 1 g / L, vitamin B1 0.5 g / L, and the solvent is water.

[0115] In the following specific embodiments of the present invention, the content (purity), melting point, content of ignition residue, water content, and content of heavy metals (calculated as Pb) of succinic acid in the bio-based succinic acid can be obtained by the methods in GB / T 34686-2017; the methods for other tests are as follows:

[0116] (1) Content of N element: Tested by the KDN-04A full-automatic Kjeldahl nitrogen analyzer through the Kjeldahl method. First, digest with concentrated sulfuric acid and copper sulfate to convert all the nitrogen in the bio-based succinic acid to be tested into inorganic nitrogen (ammonium salt), distill ammonia with alkali, absorb it with boric acid, and finally titrate with a standard acid (0.02 mol / L hydrochloric acid) to calculate the nitrogen element content.

[0117] (2) Content of S element: Tested with a sulfur element analyzer. Place the prepared succinic acid sample at the sample position of the ZDL-YE100D full-automatic sulfur analyzer (Hebi Yaoshi Electronic Technology Co., Ltd.), start the instrument for testing, and record the sulfur content result displayed by the instrument after the test is completed.

[0118] (3) Content of P element: The phosphomolybdic acid colorimetric method is adopted. The specific steps include: ① Mix water and ascorbic acid evenly to obtain an ascorbic acid solution with a mass concentration of 10%; ② Prepare molybdate solution: Weigh 13 g of ammonium molybdate into a beaker, add 100 mL of water to dissolve it; weigh 0.35 g of potassium antimony tartrate oxide, add 100 mL of water to dissolve it; slowly add the ammonium molybdate solution to the beaker containing 300 mL of sulfuric acid solution under stirring, then add the potassium antimony tartrate oxide solution and mix evenly. Transfer the mixed solution to a brown glass bottle and store it in a cool place; ③ Phosphate stock solution: Dry potassium dihydrogen phosphate at 100 °C for 2 hours, place it in a desiccator and let it stand overnight; weigh 0.217 g of potassium dihydrogen phosphate, dissolve it in water and transfer it to a 1000 mL volumetric flask, add 5 mL of sulfuric acid solution, and make up the volume to make the phosphorus concentration in this solution 50 μg / mL; ④ Phosphate standard solution: Measure 10 mL of the phosphate stock solution into a 250 mL volumetric flask, add water to make up the volume to make the phosphorus concentration in this solution 2 μg / mL. ⑤ Plot the standard curve: Accurately pipette 0 mL, 0.5 mL, 1.0 mL, 3.0 mL, 5.0 mL, 10.0 mL, and 15.0 mL of the phosphate standard working solution into 50 mL stoppered colorimetric tubes respectively, add water to the scale line, add 1 mL of 10% ascorbic acid solution to each colorimetric tube, mix evenly, add 2 mL of molybdate solution after 30 s and mix well, let it stand for 15 min. Use a 10 mm colorimetric cell, at a wavelength of 700 nm, with the zero-concentration solution as the reference, measure the absorbance, and plot the P element standard curve; ⑥ Sample determination: Weigh 10.0 g of the succinic acid sample to be measured into a beaker, dissolve it in water, transfer it to a 100 mL volumetric flask, make up the volume. Pipette 0.1 mL of the sample solution into a colorimetric tube, add 1 mL of 10% ascorbic acid solution to the colorimetric tube, mix evenly, add 2 mL of molybdate solution after 30 s and mix well, let it stand for 15 min. Use a 10 mm colorimetric cell, at a wavelength of 700 nm, with the zero-concentration solution as the reference, measure the absorbance, substitute it into the P element standard curve, and obtain the content of the P element.

[0119] (4) Yellow index (YI): According to the method in Standard GB / T 39822-2021, place the bio-based succinic acid to be measured in a cylindrical container made of transparent glass and test it with a yellow index meter. The light source is the CIE standard D65 light source.

[0120] Example 1

[0121] A bio-based succinic acid and its preparation method, the preparation method includes the following steps:

[0122] (1) Preparation of seed liquid:

[0123] Inoculate a single colony of Actinobacillus succinogenes on the flat plate into the sterilized seed medium, and culture it in an incubator at 34 °C for 14 h to obtain a seed solution.

[0124] (2) Preparation of fermentation broth:

[0125] Inoculate the seed solution obtained in step (1) into the fermentation medium at an inoculation amount of 10%, and perform aerobic fermentation and anaerobic fermentation in sequence to obtain a fermentation broth;

[0126] Among them, the pH value of the aerobic fermentation is 6.6, the ventilation rate is 2 vvm, the stirring speed is 280 rpm, the temperature is 33 °C, and the time is 12 h;

[0127] The pH value of the anaerobic fermentation is 6.0, the stirring speed is 220 rpm, the temperature is 37 °C, and the time is 40 h;

[0128] (3) Preparation of bio-based succinic acid:

[0129] Perform nanofiltration (the pore size of the filter membrane is 3 nm) on the fermentation broth obtained in step (2) at 55 °C, and collect the filtrate;

[0130] Perform ion exchange on the filtrate: First, adjust the pH value of the filtrate to 6.2 with a 5 wt% sodium hydroxide aqueous solution, and then pass it through a resin column filled with macroporous strong acid cation exchange resin (D001 type). The system temperature is 40 °C, and the residence time is 40 min to complete the first cation exchange and obtain a first clear liquid;

[0131] Adjust the pH value of the first clear liquid to 7.1 with a 5 wt% sodium hydroxide aqueous solution, and then pass it through a resin column filled with macroporous weak base anion exchange resin (D301 type). The system temperature is 35 °C, and the residence time is 100 min to complete the first anion exchange and obtain a second clear liquid;

[0132] Adjust the pH value of the second clear liquid to 6.0 with a 5 wt% sodium hydroxide aqueous solution, and then pass it through a resin column filled with homogeneous strong acid cation exchange resin (Tulsimer T-42). The system temperature is 40 °C, and the residence time is 30 min to complete the second cation exchange and obtain a third clear liquid;

[0133] Adjust the pH value of the third clear liquid to 7.8 with a 5 wt% sodium hydroxide aqueous solution, and then pass it through a resin column filled with macroporous polystyrene anion exchange resin (LSC-770). The system temperature is 40 °C, and the residence time is 25 min to complete the second anion exchange and obtain a permeate;

[0134] Use activated carbon to decolorize the permeate. The decolorization temperature is 50 °C, and the time is 40 min to obtain a decolorized liquid;

[0135] The decolorized solution is subjected to evaporation and concentration at a temperature of 60 °C, a system pressure of 15 kPa, and a concentration multiple of 3 times to obtain a concentrated solution;

[0136] The concentrated solution is crystallized at 10 °C and a system pressure of 70 kPa. The solid is collected and dried at 80 °C to obtain a crude product;

[0137] The crude product is redissolved in water at 65 °C and recrystallized at 10 °C and a system pressure of 70 kPa, followed by centrifugal separation and drying at 80 °C to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0138] Example 2

[0139] A bio-based succinic acid and its preparation method, the preparation method comprising the following steps:

[0140] (1) Preparation of the seed solution:

[0141] A single colony of Actinobacillus succinogenes on the plate is inoculated into the sterilized seed medium and cultured in an incubator at 35 °C for 12 h to obtain a seed solution.

[0142] (2) Preparation of the fermentation broth:

[0143] The seed solution obtained in step (1) is inoculated into the fermentation medium at an inoculation amount of 8%, and aerobic fermentation and anaerobic fermentation are carried out in sequence to obtain a fermentation broth;

[0144] Among them, the pH value of the aerobic fermentation is 6.8, the ventilation rate is 4 vvm, the stirring speed is 230 rpm, the temperature is 35 °C, and the time is 10 h;

[0145] The pH value of the anaerobic fermentation is 6.5, the stirring speed is 200 rpm, the temperature is 38 °C, and the time is 48 h;

[0146] (3) Preparation of bio-based succinic acid:

[0147] The fermentation broth obtained in step (2) is subjected to nanofiltration at 50 °C (the pore size of the filter membrane is 1 nm), and the filtrate is collected;

[0148] Ion exchange is carried out on the filtrate: First, the pH value of the filtrate is adjusted to 6.1 with a 5 wt% aqueous sodium hydroxide solution, and then it is passed through a resin column filled with macroporous strong acid cation exchange resin (C100EDL type). The system temperature is 35 °C, and the residence time is 50 min to complete the first cation exchange to obtain a first clear liquid;

[0149] After adjusting the pH value of the first supernatant to 7.2 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with macroporous weakly basic anion exchange resin (D354 type), the system temperature is 40 °C, and the residence time is 80 min to complete the first anion exchange and obtain a second supernatant;

[0150] After adjusting the pH value of the second supernatant to 6.0 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with uniform particle strongly acidic cation exchange resin (Tulsimer T-42), the system temperature is 40 °C, and the residence time is 30 min to complete the second cation exchange and obtain a third supernatant;

[0151] After adjusting the pH value of the third supernatant to 7.6 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with macroporous polystyrene anion exchange resin (A-107), the system temperature is 35 °C, and the residence time is 35 min to complete the second anion exchange and obtain a permeate;

[0152] The permeate is decolorized with activated carbon at a temperature of 50 °C for 40 min to obtain a decolorized solution;

[0153] The decolorized solution is evaporated and concentrated at a temperature of 70 °C, a system pressure of 25 kPa, and a concentration multiple of 5 times to obtain a concentrated solution;

[0154] The concentrated solution is crystallized at 20 °C and a system pressure of 60 kPa, the solid is collected and dried at 85 °C to obtain a crude product;

[0155] The crude product is redissolved in water at 75 °C and recrystallized at 20 °C and a system pressure of 60 kPa, then centrifuged and dried at 85 °C to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0156] Example 3

[0157] A bio-based succinic acid and its preparation method, the difference between the preparation method and that of Example 1 lies in step (3), specifically as follows:

[0158] The fermentation broth (prepared in the same way as in Example 1) is subjected to nanofiltration at 60 °C (the pore size of the filter membrane is 2 nm), and the filtrate is collected;

[0159] Ion exchange is carried out on the filtrate: First, the pH value of the filtrate is adjusted to 6.0 with a 5 wt% sodium hydroxide aqueous solution, and then it is passed through a resin column filled with macroporous strong acid cation exchange resin (D001 type), the system temperature is 45 °C, and the residence time is 35 min to complete the first cation exchange and obtain a first supernatant;

[0160] After adjusting the pH value of the first supernatant to 8.0 with a 5 wt% aqueous sodium hydroxide solution, it is passed through a resin column filled with macroporous weak-base anion exchange resin (D370 type). The system temperature is 30 °C and the residence time is 120 min to complete the first anion exchange and obtain a second supernatant;

[0161] After adjusting the pH value of the second supernatant to 5.9 with a 5 wt% aqueous sodium hydroxide solution, it is passed through a resin column filled with uniform particle strong-acid cation exchange resin (Tulsimer T-42H). The system temperature is 50 °C and the residence time is 20 min to complete the second cation exchange and obtain a third supernatant;

[0162] After adjusting the pH value of the third supernatant to 7.9 with a 5 wt% aqueous sodium hydroxide solution, it is passed through a resin column filled with macroporous polystyrene anion exchange resin (A-107). The system temperature is 45 °C and the residence time is 20 min to complete the second anion exchange and obtain a permeate;

[0163] The permeate is decolorized with activated carbon at a temperature of 55 °C for 50 min to obtain a decolorized solution;

[0164] The decolorized solution is evaporated and concentrated at a temperature of 75 °C, a system pressure of 30 kPa, and a concentration multiple of 8 times to obtain a concentrated solution;

[0165] The concentrated solution is crystallized at 15 °C and a system pressure of 70 kPa. The solid is collected and dried at 80 °C to obtain a crude product;

[0166] The crude product is redissolved in water at 75 °C and recrystallized at 20 °C and a system pressure of 60 kPa, then centrifuged and dried at 85 °C to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0167] Example 4

[0168] A bio-based succinic acid and its preparation method. The difference between the preparation method and that of Example 1 lies in step (3) as follows:

[0169] The fermentation broth (prepared in the same way as in Example 1) is subjected to nanofiltration at 50 °C (the pore size of the filter membrane is 2 nm), and the filtrate is collected;

[0170] Ion exchange is carried out on the filtrate: First, the pH value of the filtrate is adjusted to 5.8 with a 5 wt% aqueous sodium hydroxide solution, and then it is passed through a resin column filled with macroporous strong-acid cation exchange resin (C100EDL type). The system temperature is 40 °C and the residence time is 50 min to complete the first cation exchange and obtain a first supernatant;

[0171] After adjusting the pH value of the first supernatant to 6.2 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with uniform particle strong acidic cation exchange resin (Tulsimer T-42). The system temperature is 45 °C and the residence time is 30 min to complete the second cation exchange, obtaining a second supernatant;

[0172] After adjusting the pH value of the second supernatant to 7.8 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with macroporous weak base anion exchange resin (D354 type). The system temperature is 35 °C and the residence time is 100 min to complete the first anion exchange, obtaining a third supernatant;

[0173] After adjusting the pH value of the third supernatant to 7.8 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with macroporous polystyrene anion exchange resin (A-107). The system temperature is 40 °C and the residence time is 25 min to complete the second anion exchange, obtaining a permeate;

[0174] The permeate is decolorized with activated carbon at a temperature of 55 °C for 50 min to obtain a decolorized solution;

[0175] The decolorized solution is evaporated and concentrated at a temperature of 75 °C, a system pressure of 30 kPa, and a concentration multiple of 8 times to obtain a concentrated solution;

[0176] The concentrated solution is crystallized at 15 °C and a system pressure of 70 kPa, the solid is collected and dried at 80 °C to obtain a crude product;

[0177] The crude product is redissolved in water at 75 °C and recrystallized at 20 °C and a system pressure of 60 kPa, then centrifuged and dried at 85 °C to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0178] Example 5

[0179] A bio-based succinic acid and its preparation method. The difference between the preparation method and that of Example 1 lies in step (3), which is specifically as follows:

[0180] The fermentation broth (prepared in the same way as in Example 1) is subjected to nanofiltration at 55 °C (the pore size of the filter membrane is 2 nm), and the filtrate is collected;

[0181] Ion exchange is carried out on the filtrate: First, the pH value of the filtrate is adjusted to 6.0 with a 5 wt% sodium hydroxide aqueous solution, and then it is passed through a resin column filled with macroporous strong acid cation exchange resin (D001 type). The system temperature is 40 °C and the residence time is 60 min to complete the first cation exchange, obtaining a first supernatant;

[0182] After adjusting the pH value of the first supernatant to 7.5 with a 5 wt% aqueous sodium hydroxide solution, it is passed through a resin column filled with macroporous weakly basic anion exchange resin (D301 type). The system temperature is 40 °C and the residence time is 70 min to complete the first anion exchange and obtain a second supernatant;

[0183] After adjusting the pH value of the second supernatant to 6.3 with a 5 wt% aqueous sodium hydroxide solution, it is passed through a resin column filled with uniform particle strong acidic cation exchange resin (Tulsimer T-42H). The system temperature is 50 °C and the residence time is 20 min to complete the second cation exchange and obtain a third supernatant;

[0184] After adjusting the pH value of the third supernatant to 7.2 with a 5 wt% aqueous sodium hydroxide solution, it is passed through a resin column filled with macroporous polystyrene anion exchange resin (LSC-770). The system temperature is 35 °C and the residence time is 30 min to complete the second anion exchange and obtain a permeate;

[0185] The permeate is decolorized with activated carbon at a temperature of 55 °C for 40 min to obtain a decolorized solution;

[0186] The decolorized solution is evaporated and concentrated at a temperature of 80 °C, a system pressure of 20 kPa, and a concentration multiple of 5 times to obtain a concentrated solution;

[0187] The concentrated solution is crystallized at 15 °C and a system pressure of 60 kPa. The solid is collected and dried at 80 °C to obtain a crude product;

[0188] The crude product is redissolved in water at 65 °C and recrystallized at 10 °C and a system pressure of 70 kPa, followed by centrifugal separation and drying at 80 °C to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0189] Example 6

[0190] A bio-based succinic acid and its preparation method. The difference between the preparation method and that of Example 1 lies in the different ion exchange methods in step (3), specifically as follows:

[0191] The fermentation broth obtained in step (2) is subjected to nanofiltration (membrane pore size is 3 nm) at 55 °C, and the filtrate is collected;

[0192] Ion exchange is performed on the filtrate: The filtrate (pH value is 2.9) is passed through a resin column filled with macroporous strong acid cation exchange resin (D001 type). The system temperature is 40 °C and the residence time is 40 min to complete the first cation exchange and obtain a first supernatant;

[0193] Pass the first supernatant (pH value 2.9) through a resin column filled with macroporous weakly basic anion exchange resin (D301 type), with the system temperature at 35°C and a residence time of 100 min to complete the first anion exchange and obtain the second supernatant;

[0194] Pass the second supernatant (pH value 2.8) through a resin column filled with uniform particle strongly acidic cation exchange resin (Tulsimer T-42), with the system temperature at 40°C and a residence time of 30 min to complete the second cation exchange and obtain the third supernatant;

[0195] Pass the third supernatant (pH value 2.9) through a resin column filled with macroporous polystyrene anion exchange resin (LSC-770), with the system temperature at 40°C and a residence time of 25 min to complete the second anion exchange and obtain the permeate;

[0196] The permeate is decolorized, evaporated and concentrated, crystallized, redissolved, recrystallized and dried according to the same method in Example 1 to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0197] Example 7

[0198] A bio-based succinic acid and its preparation method. The difference between the preparation method and that of Example 1 lies in the different ion exchange method in step (3), which is specifically as follows:

[0199] Perform nanofiltration (membrane pore size 3 nm) on the fermentation broth obtained in step (2) at 55°C and collect the filtrate;

[0200] Perform ion exchange on the filtrate: Pass the filtrate (pH value 2.9) through a resin column filled with macroporous strong acid cation exchange resin (D001 type), with the system temperature at 40°C and a residence time of 40 min to complete the first cation exchange and obtain the first supernatant;

[0201] After adjusting the pH value of the first supernatant to 7.1 with 5 wt% sodium hydroxide aqueous solution, pass it through a resin column filled with macroporous weakly basic anion exchange resin (D301 type), with the system temperature at 35°C and a residence time of 100 min to complete the first anion exchange and obtain the second supernatant;

[0202] Pass the second supernatant (pH value 2.8) through a resin column filled with uniform particle strongly acidic cation exchange resin (Tulsimer T-42), with the system temperature at 40°C and a residence time of 30 min to complete the second cation exchange and obtain the third supernatant;

[0203] After adjusting the pH value of the third clear liquid to 7.8 with a 5 wt% sodium hydroxide aqueous solution, it is passed through a resin column filled with macroporous polystyrene anion exchange resin (LSC-770), the system temperature is 40 °C, and the residence time is 25 min to complete the second anion exchange, obtaining a permeate;

[0204] The permeate is decolorized, evaporated and concentrated, crystallized, redissolved, recrystallized and dried in the same manner as in Example 1 to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0205] Example 8

[0206] A bio-based succinic acid and a preparation method thereof. The difference between the preparation method and that of Example 1 lies in the different ion exchange methods in step (3), which are specifically as follows:

[0207] The fermentation broth obtained in step (2) is subjected to nanofiltration (the pore size of the filter membrane is 3 nm) at 55 °C, and the filtrate is collected;

[0208] Ion exchange is carried out on the filtrate: First, the pH value of the filtrate is adjusted to 6.2 with a 5 wt% sodium hydroxide aqueous solution, and then it is passed through a resin column filled with macroporous strong acid cation exchange resin (D001 type), the system temperature is 40 °C, and the residence time is 40 min to complete the first cation exchange, obtaining a first clear liquid;

[0209] The first clear liquid (pH value is 2.9) is passed through a resin column filled with macroporous weak base anion exchange resin (D301 type), the system temperature is 35 °C, and the residence time is 100 min to complete the first anion exchange, obtaining a second clear liquid;

[0210] The pH value of the second clear liquid is adjusted to 6.0 with a 5 wt% sodium hydroxide aqueous solution, and then it is passed through a resin column filled with homogeneous strong acid cation exchange resin (Tulsimer T-42), the system temperature is 40 °C, and the residence time is 30 min to complete the second cation exchange, obtaining a third clear liquid;

[0211] The third clear liquid (pH value is 2.8) is passed through a resin column filled with macroporous polystyrene anion exchange resin (LSC-770), the system temperature is 40 °C, and the residence time is 25 min to complete the second anion exchange, obtaining a permeate;

[0212] The permeate is decolorized, evaporated and concentrated, crystallized, redissolved, recrystallized and dried in the same manner as in Example 1 to obtain the bio-based succinic acid, and its component information is shown in Table 1.

[0213] Comparative Example 1

[0214] A bio - based succinic acid and its preparation method. The difference from Example 1 is only that the ion - exchange method is different. In Comparative Example 1, the second cation - exchange and the second anion - exchange are not carried out, and the obtained second supernatant is directly decolorized; other steps and parameters are the same as those in Example 1, and the bio - based succinic acid is obtained, and its component information is shown in Table 1.

[0215] Comparative Example 2

[0216] A bio - based succinic acid and its preparation method. The difference from Example 1 is only that the ion - exchange method is different. In Comparative Example 2, the second anion - exchange is not carried out, and the obtained third supernatant is directly decolorized; other steps and parameters are the same as those in Example 1, and the bio - based succinic acid is obtained, and its component information is shown in Table 1.

[0217] Comparative Example 3

[0218] A bio - based succinic acid and its preparation method. The difference from Example 1 is only that the ion - exchange method is different. In Comparative Example 3, the second cation - exchange is not carried out, that is, the second supernatant is subjected to the second anion - exchange to obtain a permeate; other steps and parameters are the same as those in Example 1, and the bio - based succinic acid is obtained, and its component information is shown in Table 1.

[0219] Table 1

[0220]

[0221] According to the data in Table 1, in the bio - based succinic acid provided in Examples 1 - 8 of the present invention, the mass content of N element is 1.1 - 8.2 ppm, further preferably 1.1 - 2.1 ppm; the mass content of S element is 0.33 - 1.5 ppm, further preferably 0.33 - 0.63 ppm; the mass content of P element is 0.8 - 6.3 ppm, further preferably 0.8 - 2.2 ppm; the purity of succinic acid is 99.76 - 99.85%; the water content is 380 - 520 ppm; the heavy - metal content ≤ 1 ppm; the content of ignition residue is 62 - 85 ppm. The succinic acid has high purity, low impurity content, YI value ≤ 0.85, further preferably ≤ 0.7, light color. When it is used in the synthesis of chemical products such as polyester, 1,4 - butanediol, succinic anhydride, γ - butyrolactone, tetrahydrofuran, etc., it can effectively inhibit side reactions, obtain target products with high yield and high purity, and make the products have better hue and physical properties.

[0222] The present invention obtains a fermentation broth containing succinic acid through microbial fermentation, and designs a purification method including filtration, multiple ion - exchange treatments, decolorization, concentration and crystallization, realizes the effective separation of impurities and succinic acid, and obtains a bio - based succinic acid containing specific contents of N, S and P elements, high purity and ultra - low impurity content.

[0223] Compared with Example 1, the number of ion exchange times in Comparative Examples 1-3 is less, resulting in poor impurity removal effect, significant increase in the content of three elements of nitrogen, phosphorus and sulfur, exceeding the limit value of the present invention, high yellow index of succinic acid and poor hue.

[0224] The following are exemplary application examples of the biobased succinic acid of the present invention for the preparation of 1,4-butanediol (BDO). In the following specific embodiments of the present invention, reagents whose preparation methods are not specified are all conventional commercially available chemicals.

[0225] Application Examples 1-8

[0226] The preparation method of BDO includes the following steps:

[0227] (1) Add biobased succinic acid (from Examples 1-8 respectively) and methanol (purity ≥ 99.0%, Beijing Innochem Technology Co., Ltd.) into a reaction kettle according to an alcohol-acid molar ratio of 10:1, add solid phosphotungstic acid as a catalyst, and the catalyst addition amount is 1% of the total mass of the raw materials. React at 110 °C for 5 h to obtain an esterified product;

[0228] (2) Add the esterified product and catalyst (Cu1Fe1Al0.5 catalyst) obtained in step (1) into a reaction kettle, and the addition amount of the catalyst is 1.5% of the total mass of the raw materials. Then, introduce hydrogen into the reaction kettle as a reducing agent, and the volume ratio of hydrogen to the esterified product is 180:1. React at 190 °C and 5 MPa for 8 h to obtain a crude product; Distill and purify the crude product, with a distillation pressure of 0.01 MPa, and collect the fractions in the range of 150-180 °C to obtain the BDO.

[0229] Control Examples 1-3

[0230] The preparation method of BDO is only different from that of the application example in that the biobased succinic acid provided in Comparative Examples 1-3 is used to replace the biobased succinic acid from Example 1 of the present invention in the application example, and the types, amounts and process steps of other materials are the same as those in the application example to obtain BDO.

[0231] Test the purity of BDO according to the method in Standard GB / T 24768-2009, and test the chromaticity of BDO according to the method in Standard GB / T 3143-1982. The obtained data are shown in Table 2:

[0232] Table 2

[0233]

[0234] According to the data in Table 2, since the contents of the three elements N, P, and S in the biobased succinic acid of Examples 1-5 of the present invention are within a specific range, side reactions can be inhibited and by-products can be reduced, resulting in BDO with a purity ≥99.7% and a chromaticity ≤7.1, obtaining BDO with high yield, high purity, and low chromaticity. The biobased succinic acid in Comparative Examples 1-3 has high contents of N, P, and S elements, which will cause side reactions in the esterification stage. Succinic acid is dehydrated by heating to form succinic anhydride, affecting the purity and chromaticity of BDO.

[0235] The applicant declares that the present invention uses the above examples to illustrate the biobased succinic acid and its preparation method and application of the present invention, but the present invention is not limited to the above examples, that is, it does not mean that the present invention must rely on the above examples to be implemented. Those skilled in the art should understand that any improvement to the present invention, the equivalent substitution of each raw material of the product of the present invention, the addition of auxiliary components, the selection of specific methods, etc., all fall within the protection scope and the disclosure scope of the present invention.

Claims

1. A bio-based succinic acid, characterized in that, The bio-based succinic acid includes succinic acid, N element, S element and P element; the mass content of N element in the bio-based succinic acid is 0.1 - 10 ppm, the mass content of S element is 0.1 - 3 ppm, and the mass content of P element is 0.1 - 10 ppm.

2. The biobased succinic acid according to claim 1, wherein The mass content of succinic acid in the bio-based succinic acid ≥ 99.7%; Preferably, the yellowness index of the bio-based succinic acid is 0.01 - 1.

0.

3. The biobased succinic acid according to claim 1, wherein The bio-based succinic acid also includes water and / or heavy metals; Preferably, the mass content of water in the bio-based succinic acid is 0.1 - 4000 ppm; Preferably, the mass content of heavy metals in the bio-based succinic acid is 0.01 - 10 ppm.

4. The biobased succinic acid according to claim 1, wherein The melting point of the bio-based succinic acid is 185 - 188 °C; Preferably, the content of ignition residue of the bio-based succinic acid is 10 - 100 ppm.

5. A method for preparing the bio-based succinic acid according to any one of claims 1-4, characterized in that, The preparation method includes: Inoculating the seed liquid of succinic acid-producing strain into a culture medium, and successively performing aerobic fermentation and anaerobic fermentation to obtain a fermentation broth; Filtering the fermentation broth to obtain a filtrate; Performing at least 4 times of ion exchange treatment on the filtrate to obtain a permeate; The permeate is subjected to decolorization, concentration and crystallization to obtain the bio-based succinic acid.

6. The preparation method according to claim 5, characterized in that, The succinic acid-producing strain includes Escherichia coli, Actinobacillus succinogenes or Anaerobiospirillum; Preferably, the inoculation amount of the seed liquid is 1 - 10%; Preferably, the culture medium includes the following components: glucose 80 - 150 g / L, yeast powder 10 - 30 g / L, urea 5 - 20 g / L, dipotassium hydrogen phosphate 5 - 10 g / L, potassium dihydrogen phosphate 5 - 10 g / L, magnesium sulfate 0.1 - 2 g / L, vitamin 0.1 - 2 g / L.

7. The preparation method according to claim 5, characterized in that, The pH value of the aerobic fermentation is 6.5 - 7.5; Preferably, the aeration rate of the aerobic fermentation is 1 - 5 vvm; Preferably, the stirring speed of the aerobic fermentation is 150 - 500 rpm; Preferably, the temperature of the aerobic fermentation is 30 - 35 °C, and the time is 8 - 12 h; Preferably, the pH value of the anaerobic fermentation is 5.5 - 6.5; Preferably, the stirring speed of the anaerobic fermentation is 200 - 350 rpm; Preferably, the temperature of the anaerobic fermentation is 33 - 40 °C, and the time is 36 - 48 h.

8. The preparation method according to claim 5, characterized in that, The filtering method includes any one or a combination of at least two of microfiltration, nanofiltration, ultrafiltration or reverse osmosis; Preferably, the temperature of the filtering is 40 - 60 °C.

9. The preparation method according to claim 5, characterized in that, The ion exchange treatment includes at least 2 times of cation exchange and at least 2 times of anion exchange; Preferably, before each cation exchange, the pH value of the solution to be treated is adjusted to 5.5 - 6.5; Preferably, before each anion exchange, the pH value of the solution to be treated is adjusted to 7.0 - 8.0; Preferably, the temperature of the ion exchange treatment is 30 - 55 °C; Preferably, the residence time of each ion exchange is independently 15 - 120 min; Preferably, the temperature of the concentration is 60 - 80 °C, and the system pressure is 10 - 40 kPa; Preferably, the concentration multiple is 2 - 10 times; Preferably, the temperature for crystallization is 10 - 30°C and the system pressure is 60 - 80 kPa.

10. Use of a biobased succinic acid as claimed in any one of claims 1 - 4 in the preparation of 1,4 - butanediol, a five - membered heterocyclic compound or a polyester; Preferably, the five - membered heterocyclic compound includes succinic anhydride, γ - butyrolactone or tetrahydrofuran.

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