Sebacic acid extraction and purification method and product

Abstract

The invention provides a sebacic acid extraction and purification method and a product, and the method comprises the following steps: (1) filtering fermentation liquor of sebacic acid through a microfiltration membrane to obtain first filtrate; carrying out decoloration treatment, acidification crystallization treatment and solid-liquid separation treatment on the first filtrate to obtain a first solid; (2) mixing the first solid, alkali and water to form a solution, and carrying out decoloration treatment, acidification crystallization treatment and solid-liquid separation treatment on the solution to obtain a second solid; and (3) mixing the second solid with water to form a mixture, carrying out heat preservation treatment on the mixture at 80-115 DEG C, then cooling to 25-45 DEG C for crystallization, and carrying out solid-liquid separation treatment to obtain the product, wherein the temperature of acidification crystallization is 70-120 DEG C, and the heat preservation time is 10-90 min. According to the embodiment of the invention, the quality of the sebacic acid product is improved, and the sebacic acid product is high in purity and low in ash content and nitrogen-containing impurity content.

Description

Technical Field

[0001] The invention relates to sebacic acid, in particular to a method for extracting and purifying sebacic acid produced by a biological fermentation method. Background Art

[0002] Sebacic acid (or deca-carbon long-chain dibasic acid) refers to an aliphatic dicarboxylic acid containing 10 carbon atoms in the carbon chain. It is a type of fine chemical product with important and extensive industrial uses. It is an important raw material for high-performance polyamide textiles, high-performance polyamide engineering plastics, synthetic high-grade fragrances, high-grade polyamide hot-melt adhesives, high-temperature electrolytes, cold-resistant plasticizers, high-grade lubricants, high-grade paints and coatings, medicines and pesticides in the chemical industry.

[0003] The chemical synthesis of sebacic acid is mainly to hydrolyze castor oil under the action of a catalyst to produce ricinoleic acid, and then to obtain it by high temperature and alkaline cracking. The biological fermentation method can produce sebacic acid using petroleum byproduct wax oil, alkanes, fatty acids or their derivatives as raw materials, and ferment sebacic acid under low temperature and low pressure using the unique oxidation ability of microorganisms and the action of microbial intracellular enzymes. Therefore, it has the advantages of a wide source of raw materials, simple production process, mild production conditions, etc., and has obvious advantages over traditional chemical synthesis methods.

[0004] When using biological fermentation to produce sebacic acid, the fermentation liquid obtained usually contains multiphase components such as water phase, oil phase (such as residual oil raw materials) and solid phase (such as microbial cells, residual protein, etc.), and there is also emulsification of the water phase and the oil phase. The complex fermentation liquid system increases the difficulty of subsequent extraction and purification of sebacic acid. If the impurity content of the sebacic acid product is high, it is difficult to meet the requirements of high-end polymer products for monomer raw materials.

[0005] The patent application with publication number CN102476987A discloses a method for refining long-chain dibasic acids by combining ultrafiltration and liquid-liquid extraction. After the fermentation broth in the fermentation stage is filtered through a microfiltration membrane to remove solid particles, it is first filtered through an organic ultrafiltration membrane with a molecular flux of 3000 to 50000 Daltons to remove some proteins and pigments in the filtrate. The ultrafiltrate is then mixed with alcohol and heated to acidify. Under a certain pH value and temperature, the alcohol and ultrafiltrate are mixed and stirred for a certain time, and then liquid-liquid separation is performed. The extract phase is cooled and crystallized, and the solvent is removed to obtain a purified product.

[0006] Since organic solvents are used in the above purification process, there will be residual solvents in the wet crystal product. During the drying process, a solvent recovery device needs to be added. At the same time, the solvent in the product cannot be completely removed during the drying process, thus affecting the final performance of the product. In addition, organic solvents are easy to volatilize and lose, and the cost is high.

[0007] In summary, developing an efficient and environmentally friendly method for extracting and refining sebacic acid to further improve the quality of sebacic acid products is a very practical problem that needs to be solved urgently in the existing technology. Summary of the invention

[0008] The present invention provides a method for extracting and purifying sebacic acid, comprising the following steps:

[0009] (1) filtering the fermentation broth of sebacic acid through a microfiltration membrane to obtain a first filtrate; decolorizing, acidifying, crystallizing, and solid-liquid separation the first filtrate to obtain a first solid;

[0010] (2) mixing the first solid, a base and water to form a solution, and subjecting the solution to decolorization, acidification and crystallization, and solid-liquid separation to obtain a second solid;

[0011] (3) mixing the second solid with water to form a mixture, heat-insulating the mixture at 80 to 115° C., then cooling the mixture to 25 to 45° C. for crystallization, and performing solid-liquid separation to obtain a product;

[0012] Wherein, the temperature of the acidification crystallization in step (1) and / or step (2) is 70 to 120° C., and the insulation time is 10 to 90 minutes.

[0013] The present invention also provides a sebacic acid product. The purity of the sebacic acid product is greater than 98.5%, and / or the ash content is less than 50 ppm, and the nitrogen content is less than 35 ppm. Further, the purity of the sebacic acid product is greater than 99%, and / or the ash content is less than 35 ppm, and / or the nitrogen content is less than 30 ppm. DETAILED DESCRIPTION

[0014] Typical embodiments that embody the features and advantages of the present invention will be described in detail in the following description. It should be understood that the present invention can have various variations in different embodiments without departing from the scope of the present invention, and the descriptions therein are essentially for the purpose of illustration rather than for limiting the present invention. Among them, "first", "second", "third", etc. are used to distinguish between multiple processes or products with the same name, but are not intended to limit them.

[0015] An embodiment of the present invention provides a method for extracting and purifying sebacic acid, the method comprising the following steps:

[0016] (1) filtering the fermentation broth of sebacic acid through a microfiltration membrane to obtain a first filtrate; decolorizing, acidifying, crystallizing, and solid-liquid separation the first filtrate to obtain a first solid;

[0017] (2) mixing the first solid, a base and water to form a solution, and subjecting the solution to decolorization, acidification and crystallization, and solid-liquid separation to obtain a second solid;

[0018] (3) mixing the second solid with water to form a mixture, heat-insulating the mixture at 80 to 115° C., then cooling the mixture to 25 to 45° C. for crystallization, and performing solid-liquid separation to obtain a product;

[0019] The temperature of the acidification crystallization in step (1) and / or step (2) is 70 to 120° C., and the insulation time is 10 to 90 minutes.

[0020] In the present invention, the sebacic acid fermentation broth can be a fermentation broth obtained by a square method using decane, ten-carbon fatty acids and their derivatives as substrates and utilizing microbial fermentation; wherein the microorganisms are used to convert the terminal methyl groups of decane, ten-carbon fatty acids and their derivatives into carboxyl groups through oxidation, thereby generating sebacic acid.

[0021] In one embodiment, the concentration of the fermentation broth is 2-20 wt %, further 2-17 wt %, further 5-13.7 wt %, further 10.2-13.7 wt %. It is generally known to those skilled in the art that sebacic acid in the fermentation broth exists in the form of sebacic acid and sebacate.

[0022] In one embodiment, the sebacic acid fermentation broth may be heated to 50-100° C., or further to 70-95° C., and then filtered through a microfiltration membrane.

[0023] In one embodiment, the pH value of the sebacic acid fermentation broth is 5.0 to 12, and further 6 to 11. The pH value may be the natural pH value of the fermentation broth, or may be an adjusted pH value.

[0024] In one embodiment, the pH value of the sebacic acid fermentation broth can be adjusted to 5.0-12, further to 6-11, and then filtered through a microfiltration membrane.

[0025] In one embodiment, the pH value of the fermentation broth can be adjusted by adding alkali and / or acid, and the types of alkali include but are not limited to sodium hydroxide and / or potassium hydroxide. The types of acid include but are not limited to hydrochloric acid, sulfuric acid, and nitric acid.

[0026] In one embodiment, in step (2), the solution is first filtered through a microfiltration membrane or an ultrafiltration membrane before being decolorized.

[0027] In one embodiment, in step (2), ultrafiltration membrane filtration is performed after the decolorization treatment and before the acidification crystallization treatment.

[0028] In one embodiment, the temperature of the sebacatezucain fermentation solution for microfiltration membrane filtration is 50-100°C, further 70-95°C.

[0029] In one embodiment, the operating pressure of the microfiltration membrane filtration is 0.1 to 1.2 MPa, further 0.1 to 0.7 MPa, for example 0.2 MPa, 0.5 MPa, 0.8 MPa.

[0030] In one embodiment, the pore size of the microfiltration membrane is 0.01 to 1 micron, and further can be 0.01 to 0.2 micron.

[0031] In one embodiment, the microfiltration membrane is a ceramic microfiltration membrane.

[0032] In one embodiment, the temperature of ultrafiltration membrane filtration is 25 to 95°C, further can be 25 to 43°C, further can be 32 to 38°C.

[0033] In one embodiment, the molecular weight cut-off of the ultrafiltration membrane is 2500 to 50000 Da, and further can be 2500 to 18000 Da.

[0034] In one embodiment, the ultrafiltration membrane includes but is not limited to a ceramic membrane, a polypropylene membrane, a polysulfone membrane, a polyethersulfone membrane, and the like.

[0035] In one embodiment, in step (1) and step (2), the decolorization treatment is achieved by contacting the solution to be decolorized with a decolorizing agent.

[0036] In one embodiment, the decolorization process may include mixing the solution to be decolorized with a solid decolorizer for solid-liquid decolorization; further, the decolorization effect may be improved by stirring the solid-liquid mixture.

[0037] It is generally known to those skilled in the art that after decolorization, the decolorizing agent can be removed by centrifugation or filtration to obtain a decolorized solution.

[0038] In one embodiment, the amount of the decolorizing agent used in the decolorization treatment in step (1) and / or step (2) is 0.05-5 wt % of the mass of the solution to be decolorized, further 0.05-3 wt %, further 0.05-2 wt %.

[0039] In one embodiment, the decolorizing agent in step (1) and / or step (2) includes but is not limited to activated carbon, activated clay, diatomaceous earth, macroporous adsorption resin, etc.

[0040] In one embodiment, the temperature of the decolorization treatment in step (1) and / or step (2) is 50 to 100°C, and further 70 to 100°C.

[0041] In one embodiment, the decolorization treatment time in step (1) and / or step (2) is 10 to 180 min, further 15 to 120 min, further 15 to 90 min.

[0042] The present application study found that temperature control during the acidification crystallization process has a significant impact on the effect of removing impurities in the system. Insulation treatment at a suitable crystallization temperature can change the existence form, aggregation state and solubility of some impurities, thereby improving the effect of acidification crystallization separation of sebacic acid and impurities.

[0043] In one embodiment, during the acidification crystallization in step (1) and / or step (2), the pH value is adjusted to 2 to 5.5, and further to 2.6 to 3.9.

[0044] In one embodiment, the temperature of the acidification crystallization in step (1) and / or step (2) is 85 to 110°C, further 85 to 105°C, further 85 to 100°C.

[0045] In one embodiment, the holding time of the acidification crystallization in step (1) and / or step (2) is 20 to 65 minutes.

[0046] In one embodiment, the acidification crystallization may use inorganic acid and / or organic acid. Inorganic acid includes but is not limited to hydrochloric acid, sulfuric acid, nitric acid; organic acid includes but is not limited to acetic acid.

[0047] In one embodiment, before mixing the first solid or the second solid with water, the first solid or the second solid may be washed with water.

[0048] In step (2) of one embodiment, the purpose of using alkali is to promote the dissolution of the first solid in water, and the types of alkali include but are not limited to sodium hydroxide and / or potassium hydroxide.

[0049] In step (2) of one embodiment, heating and stirring may be performed to promote the dissolution of the first solid to form the solution.

[0050] In step (2) of one embodiment, the first solid may be mixed with an aqueous solution of an alkali to promote dissolution of the first solid.

[0051] In step (3) of one embodiment, the mass ratio of the second solid to water may be 1:(2-20), further may be 1:(3-15), further may be 1:(3-10).

[0052] In step (3) of one embodiment, the temperature of the heat preservation treatment is 80 to 115°C, preferably 90 to 105°C.

[0053] In step (3) of one embodiment, the heat preservation treatment time is 15 to 150 minutes, and can further be 30 to 120 minutes.

[0054] In step (3) of one embodiment, after the heat preservation treatment, the terminal temperature of the cooling is 25-45°C.

[0055] In step (3) of one embodiment, after the heat preservation treatment, the temperature is first lowered to T1°C (the first stage of cooling process), kept for 20 to 180 minutes, and then lowered to 25 to 45°C (the second stage of cooling process). T1°C is 75 to 102°C, and further 80 to 100°C.

[0056] In step (3) of one embodiment, the holding time at T1°C is 25 to 120 min, and further 30 to 100 min.

[0057] In step (3) of one embodiment, the average cooling rate of the first stage cooling process is smaller than the average cooling rate of the second stage cooling process.

[0058] In step (3) of one embodiment, the average cooling rate of the first cooling process is 0.5 to 10° C. / h, and can further be 1 to 9° C. / h.

[0059] In step (3) of one embodiment, the average cooling rate of the second cooling process is 5 to 20° C. / h, further can be 7 to 18° C. / h, further can be 7 to 14° C. / h.

[0060] The present application has found that in the cooling process of step (3), by keeping the temperature at T1°C for a certain period of time and then cooling it down, the impurities and the dibasic acid crystals can be better separated, so that the impurities remain in the water, further improving the purity of the dibasic acid product.

[0061] In step (3) of one embodiment, the solid obtained by the solid-liquid separation treatment can be washed with water and dried to obtain the product.

[0062] In one embodiment, the solid-liquid separation in steps (1) to (3) can be centrifugal separation or filtration separation.

[0063] The method for extracting sebacic acid according to one embodiment of the present invention can overcome the disadvantages of poor product quality and environmental pollution caused by the traditional organic solvent crystallization method, and is suitable for the extraction and purification of sebacic acid prepared by the biological fermentation method.

[0064] An embodiment of the present invention improves the quality of sebacic acid products, and the sebacic acid products have high purity, low ash content and nitrogen-containing impurity content. Subsequent application in the preparation of polyamide can improve the quality of the product.

[0065] One embodiment of the present invention provides a sebacic acid product, wherein the purity of the sebacic acid product is greater than 98.5%, and / or the ash content is less than 50 ppm, and the nitrogen content is less than 35 ppm. Further, the purity of the sebacic acid product is greater than 99%, and / or the ash content is less than 35 ppm, and / or the nitrogen content is less than 30 ppm.

[0066] The following is a further description of the method for extracting sebacic acid according to one embodiment of the present invention by using a specific example. The raw materials used, unless otherwise specified, are commercially available, and the test methods used are as follows:

[0067] 1. Gas chromatography detection of sebacic acid purity

[0068] A standard sebacic acid sample was used as a control, with reference to GB5413.27-2010 Determination of fatty acids in infant foods and dairy products.

[0069] 2. Ash content detection

[0070] Take the sample to be tested and burn it in a crucible, then burn it in a muffle furnace at 700-800℃ for 2h, measure the weight after cooling to constant weight, and calculate the percentage weight.

[0071] 3. Total nitrogen determination

[0072] The Kjeldahl method was used for nitrogen determination.

[0073] 4. Alkane residue detection

[0074] Detected by gas chromatography, area normalization method.

[0075] Example 1 Preparation of Sebacic Acid Fermentation Broth

[0076] Referring to the fermentation method of Example 4 in the Chinese patent application number CN200410018255.7 and publication number CN1570124A, decane is used as a fermentation substrate to ferment and produce sebacic acid, and the concentration of the sebacic acid fermentation liquid is 9.7wt%.

[0077] Example 2 Preparation of Sebacic Acid Fermentation Broth

[0078] The strain used in the fermentation: Candida tropicalis CAT H1614, deposited in China Center for Type Culture Collection (CCTCC), Wuhan University, Wuhan, China, with a deposit number of CCTCC NO: M2013143, which has been disclosed in Chinese patent CN110218661A.

[0079] Fermentation method: Inoculate the glycerol tube strain of tropical Candida CAT H1614 in a seed bottle containing 30ml YPD liquid medium (glucose 2%, yeast extract 1%, peptone 2%), pH natural, control the temperature at 29°C, and culture at 220rpm on a shaker for 24 hours. Take the shake flask seeds and inoculate them in a seed tank filled with seed medium (sucrose 2.0%, yeast extract 0.5%, corn steep liquor 0.4%, potassium dihydrogen phosphate 0.8% and urea 0.3%), with an inoculation amount of 10%, control the temperature at 29°C, ventilation volume 0.4vvm, tank pressure 0.08MPa, culture for 18h, OD 620 When the pH reaches 0.7, the fermentation is inoculated into a fermentation tank containing a fermentation medium (glucose 3.0%, yeast extract 0.8%, corn steep liquor 0.6%, potassium nitrate 0.5%, potassium dihydrogen phosphate 0.5% and ammonium sulfate 0.3%) for fermentation conversion, and the inoculum amount is 20% (v / v). The fermentation temperature is controlled at 30°C, the ventilation volume is 0.32vvm, the tank pressure is 0.08MPa, and the dissolved oxygen is maintained at more than 20% during the fermentation process. The early stage of fermentation is mainly based on bacterial growth, and the initial pH of fermentation is about 6.5. With the growth of microorganisms, the pH of the fermentation liquid gradually decreases, and the pH of the fermentation system during the bacterial growth period is controlled to be 4.0. When the bacterial optical density (OD620) is above 0.5 (diluted 30 times), the fermentation substrate decane is added, and the pH of the fermentation system is controlled to be 5.0. Decane is added in batches after fermentation for 15 to 20 hours, and the decane content in the fermentation liquid is controlled to be 3 to 5%. Finally, a fermentation liquid with a concentration of 11.3wt% is obtained.

[0080] Example 3 Extraction and purification of sebacic acid

[0081] The sebacic acid fermentation solution of Example 1 was used as raw material for extraction and purification.

[0082] (1) filtering the fermentation broth of sebacic acid through a microfiltration membrane to obtain a first filtrate; decolorizing, acidifying, crystallizing, and filtering the first filtrate through a plate and frame to obtain a first solid;

[0083] (2) adding the first solid to water, adding alkali to dissolve the first solid to form a solution, filtering the solution with an ultrafiltration membrane to obtain a second filtrate; decolorizing the second filtrate, acidifying and crystallizing it, and filtering it with a plate and frame to obtain a second solid;

[0084] (3) The second solid is mixed with water to form a mixture, the mixture is kept warm at 100° C., then cooled for crystallization, and centrifuged. The obtained solid is washed with water and dried to obtain a sebacic acid product.

[0085] in,

[0086] In step (1), the pH value of the sebacic acid fermentation broth is adjusted to 9.2;

[0087] In step (1), the microfiltration membrane filtration is carried out using a ceramic microfiltration membrane, the temperature of the microfiltration membrane filtration of the fermentation broth is 90° C., the operating pressure is 0.3 MPa, and the pore size of the microfiltration membrane is 0.05 μm;

[0088] In step (1), the decolorization process is to use activated carbon for decolorization, the amount of activated carbon used is 0.15wt% of the mass of the solution to be decolorized, the decolorization temperature is 80°C, the decolorization time is 35min, and after decolorization, the solution is filtered through a plate and frame to obtain a clear solution, which is used for acidification and crystallization;

[0089] In step (1), the acidification crystallization is carried out by adjusting the pH to 3.0 with sulfuric acid, the temperature of the acidification crystallization is 95° C., and the temperature is kept at 95° C. for 30 min;

[0090] In step (2), the base is sodium hydroxide;

[0091] In step (2), the ultrafiltration membrane filtration temperature is 35° C., and the molecular weight cutoff of the ultrafiltration membrane is 10000 Da;

[0092] In step (2), the decolorization treatment is to use activated carbon for decolorization, the amount of activated carbon used is 0.2wt% of the mass of the solution to be decolorized, the decolorization temperature is 80°C, the decolorization time is 25min, and after decolorization, the solution is filtered through a plate and frame to obtain a clear solution, which is used for acidification crystallization;

[0093] In step (2), the acidification crystallization is to adjust the pH to 3.0 with sulfuric acid, the temperature of the acidification crystallization is 95° C., and the temperature is kept at 95° C. for 30 min;

[0094] In step (3), the mass ratio of the second solid to water is 1:8; the temperature is kept at 100°C for 90 minutes, then cooled to 95°C, kept at 95°C for 60 minutes, and then cooled to 30°C. The average cooling rate from 100°C to 95°C is 5°C / h, and the average cooling rate from 95°C to 30°C is 14°C / h.

[0095] Example 4 Extraction and purification of sebacic acid

[0096] In step (1), the temperature of the acidification crystallization is 105°C, and the temperature is kept at 105°C for 30 minutes; in step (2), the temperature of the acidification crystallization is 106°C, and the temperature is kept at 106°C for 30 minutes; the rest is the same as in Example 3.

[0097] Example 5 Extraction and purification of sebacic acid

[0098] In step (1), the temperature of the acidification crystallization is 77° C., and the temperature is kept at 77° C. for 30 min; in step (2), the temperature of the acidification crystallization is 75° C., and the temperature is kept at 75° C. for 30 min; the rest is the same as in Example 3.

[0099] Example 6 Extraction and purification of sebacic acid

[0100] In step (1), the temperature of the acidification crystallization is 93° C., and the crystallization is not kept at 93° C.; in step (2), the temperature of the acidification crystallization is 96° C., and the crystallization is not kept at 96° C.; the rest is the same as in Example 3.

[0101] Example 7 Extraction and purification of sebacic acid

[0102] In step (3), the cooling process is as follows: cooling from 100°C to 93°C: the average cooling rate is 14°C / h, and there is no insulation at 93°C; cooling from 93°C to 30°C: the average cooling rate is 5°C / h; the rest is the same as Example 3.

[0103] Example 8 Extraction and purification of sebacic acid

[0104] In step (1), the microfiltration membrane filtration is carried out using a ceramic microfiltration membrane, the membrane filtration temperature is 75° C., and the operating pressure is 0.4 MPa; the rest is the same as in Example 3.

[0105] Example 9 Extraction and purification of sebacic acid

[0106] In step (1), the raw sebacic acid fermentation broth prepared in Example 2 is used, and before the microfiltration membrane filtration treatment, the pH value of the sebacic acid fermentation broth is adjusted to 6.5; the rest is the same as in Example 3.

[0107] Example 10 Extraction and purification of sebacic acid

[0108] The sebacic acid fermentation broth of Example 2 was used as a raw material for extraction and purification.

[0109] (1) adjusting the pH value of the sebacic acid fermentation broth to 8.5, and then filtering the broth through a microfiltration membrane to obtain a first filtrate; decolorizing the first filtrate, acidifying and crystallizing the broth, and filtering the broth through a plate and frame to obtain a first solid;

[0110] (2) adding the first solid to water, adding alkali to dissolve the first solid to form a solution, filtering the solution with an ultrafiltration membrane to obtain a second filtrate; subjecting the second filtrate to decolorization, acidification and crystallization, and plate-and-frame filtration to obtain a second solid;

[0111] (3) The second solid is mixed with water to form a mixture, the mixture is kept warm at 95° C., then cooled to crystallize, and centrifuged. The obtained solid is washed with water and dried to obtain a sebacic acid product.

[0112] in,

[0113] In step (1), the microfiltration membrane filtration is performed using a ceramic microfiltration membrane, the temperature of the microfiltration membrane filtration of the fermentation liquid is 95° C., the operating pressure is 0.35 MPa, and the pore size of the microfiltration membrane is 0.1 um;

[0114] In step (1), the decolorization treatment is to use activated carbon for decolorization, the amount of activated carbon used is 0.3wt% of the mass of the solution to be decolorized, the decolorization temperature is 75°C, the decolorization time is 60min, and after decolorization, the solution is filtered through a plate and frame to obtain a clear solution, which is used for acidification crystallization;

[0115] In step (1), the acidification crystallization is carried out by adjusting the pH to 3.2 with sulfuric acid, the temperature of the acidification crystallization is 94° C., and the temperature is kept at 94° C. for 50 min;

[0116] In step (2), the base is sodium hydroxide;

[0117] In step (2), the temperature of the ultrafiltration membrane is 40° C., and the molecular weight cutoff of the ultrafiltration membrane is 8000 Da;

[0118] In step (2), the decolorization treatment is performed by using activated carbon, the amount of activated carbon used is 0.1wt% of the mass of the solution to be decolorized, the decolorization temperature is 95°C, the decolorization time is 50min, and after decolorization, the solution is filtered through a plate and frame to obtain a clear solution, which is used for acidification crystallization;

[0119] In step (2), the acidification crystallization is carried out by adjusting the pH to 3.0 with sulfuric acid, the temperature of the acidification crystallization is 97° C., and the temperature is kept at 97° C. for 50 min;

[0120] In step (3), the mass ratio of the second solid to water is 1:8; the temperature is kept at 100°C for 90 minutes, then cooled to 95°C, kept at 95°C for 60 minutes, and then cooled to 30°C. The average cooling rate from 100°C to 95°C is 3°C / h, and the average cooling rate from 95°C to 30°C is 12°C / h.

[0121] The products obtained in the above examples were subjected to relevant performance tests, and the specific results are shown in Table 1.

[0122] Table 1 Sebacic Acid Product Performance Table

[0123]

[0124] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0125] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for extracting and purifying sebacic acid, comprising the following steps: (1) filtering the fermentation broth of sebacic acid through a microfiltration membrane to obtain a first filtrate; decolorizing, acidifying, crystallizing, and solid-liquid separation the first filtrate to obtain a first solid; (2) mixing the first solid, alkali and water to form a solution, and subjecting the solution to decolorization, acidification and crystallization, and solid-liquid separation to obtain a second solid; (3) mixing the second solid with water to form a mixture, heat-treating the mixture at 80 to 115° C., then cooling the mixture to 25 to 45° C. for crystallization, and performing solid-liquid separation to obtain a product; in, The temperature of the acidification crystallization in step (1) and / or step (2) is 70 to 120° C., and the insulation time is 10 to 90 minutes.

2. The method according to claim 1, wherein: In step (1), the concentration of the sebacic acid fermentation broth is 2 to 20 wt %; and / or, In step (1), the temperature of microfiltration of the sebacic acid fermentation broth is 50-100° C.; and / or, The operating pressure of microfiltration membrane filtration is 0.1 to 1.2 MPa; and / or, The pore size of the microfiltration membrane is 0.01 to 1 micron.

3. The method according to claim 1, wherein: In step (1), the amount of the decolorizing agent used in the decolorization treatment is 0.05 to 5 wt% of the mass of the solution to be decolorized; and / or, The decolorizing agent includes activated carbon, activated clay, diatomaceous earth, and macroporous adsorption resin; and / or, The temperature of the decolorization treatment is 50 to 100° C.; and / or, The decolorization time is 10 to 180 minutes; and / or, In step (1), during the acidification crystallization, the pH value is adjusted to 2 to 5.5, further to 2.6 to 3.9; and / or, The temperature of the acidification crystallization is 85 to 110° C., further 85 to 105° C., further 85 to 100° C.; and / or, The holding time for acidification crystallization is 20 to 65 minutes.

4. The method according to claim 1, wherein: In step (2), the solution is first filtered through a microfiltration membrane or an ultrafiltration membrane before being decolorized; and / or, In step (2), ultrafiltration membrane filtration is performed after the decolorization treatment and before the acidification crystallization treatment.

5. The method according to claim 4, wherein: The temperature of ultrafiltration membrane filtration is 25 to 95° C., further can be 25 to 43° C., further can be 32 to 38° C.; and / or, The molecular weight cut-off of the ultrafiltration membrane is 2500 to 50000 Da, and further can be 2500 to 18000 Da; and / or, Ultrafiltration membranes include, but are not limited to, ceramic membranes, polypropylene membranes, polysulfone membranes, and polyethersulfone membranes.

6. The method according to claim 1, wherein: In step (2), the amount of the decolorizing agent used in the decolorization treatment is 0.05 to 5 wt% of the mass of the solution to be decolorized; and / or, The decolorizing agent includes activated carbon, activated clay, diatomaceous earth, and macroporous adsorption resin; and / or, The temperature of the decolorization treatment is 50 to 100° C.; and / or, The decolorization time is 10 to 180 minutes; and / or, In step (2), during the acidification crystallization, the pH value is adjusted to 2 to 5.5, further to 2.6 to 3.9; and / or, The temperature of the acidification crystallization is 85 to 110°C, further 85 to 105°C, further 85 to 100°C; and / or, The holding time for acidification crystallization is 20 to 65 minutes.

7. The method according to claim 1, wherein: In step (3), the mass ratio of the second solid to water may be 1:(2-20), further may be 1:(3-15), further may be 1:(3-10); and / or, The temperature of the heat preservation treatment is 80 to 115° C., preferably 90 to 105° C.; and / or, The heat preservation time is 15 to 150 minutes, and the further treatment time can be 30 to 120 minutes; and / or, After the insulation treatment, the final temperature of the cooling is 25-45℃.

8. The method according to claim 1, wherein: In step (3), after the heat preservation treatment, the temperature is first lowered to T1°C, kept at this temperature for 20 to 180 minutes, and then lowered to 25 to 45°C. T1°C is 75 to 102°C, and further 80 to 100°C.

9. The method according to claim 8, wherein: The holding time at T1°C is 25 to 120 min, further 30 to 100 min; and / or, The average cooling rate of the first cooling process is less than the average cooling rate of the second cooling process.

10. The method according to claim 8 or 9, wherein: In step (3), the average cooling rate of the first cooling process is 0.5-10°C / h, and the next cooling rate is 1-9°C / h; and / or, The average cooling rate of the second cooling process is 5 to 20°C / h, and further 7 to 18°C / h.

11. The method according to claim 1, wherein: In step (3), the solid obtained by solid-liquid separation is washed with water and dried to obtain the product.

12. A sebacic acid product, wherein the purity of the sebacic acid product is greater than 98.5%, and / or the ash content is less than 50 ppm, and the nitrogen content is less than 35 ppm; Furthermore, the purity of the sebacic acid product is >99%, and / or the ash content is <35 ppm, and / or the nitrogen content is <30 ppm.

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