A method for extracting sebacic acid and sebacic acid product

Abstract

The present invention provides a method for extracting sebacic acid and a sebacic acid product, the extraction method comprising the following steps: (1) using acid or alkali to adjust the fermentation liquid obtained in the process of producing sebacic acid by microbial fermentation to obtain a first mixed solution with a viscosity of 100 to 200 centipoise at 60 to 65°C; (2) heating the first mixed solution to obtain a second mixed solution with a temperature of 90 to 95°C and a viscosity of 30 to 50 centipoise, and keeping the temperature for ≥30 minutes; (3) filtering the second mixed solution to obtain a filtrate, and subjecting the filtrate to acidification crystallization, solid-liquid separation, and refining treatment to obtain a sebacic acid product. The method for extracting sebacic acid of one embodiment of the present invention can reduce acid and alkali consumption and the content of inorganic salts in water, and reduce the load of sewage treatment. The sebacic acid product has high purity.

Description

Technical Field

[0001] The invention relates to the extraction of sebacic acid, in particular to a method for extracting sebacic acid from sebacic acid fermentation broth produced by a microbial 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 between 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 sebacic acid product has low purity and high impurity content such as ash and water, it is difficult to meet the requirements of high-end polymer products for monomer raw materials.

[0005] Chinese invention patent CN101121653B discloses a method for preparing long-chain dibasic acids using C9-C18 fatty acid esters or fatty acid salts as raw materials, which includes extraction and purification of dibasic acids: adding alkali to the fermentation broth to adjust the pH to 7-11, heating to 60-100°C, and then separating the bacteria, dibasic acid clear liquid and fermentation residual substrate by centrifugation or membrane filtration. The obtained dibasic acid clear liquid is added with activated carbon in an amount not exceeding 5% of the clear liquid volume as appropriate, decolorized at 50-95°C for 10-180 minutes, filtered to remove the activated carbon, and then the decolorized liquid is heated to 50-100°C, and the pH is adjusted to 2-5 with acid for acidification and crystallization, and the acidified crystal liquid is filtered through a plate and frame filter to obtain a crude long-chain dibasic acid product; the crude long-chain dibasic acid product is dissolved with an organic solvent solution, and after the dibasic acid is fully dissolved, activated carbon in an amount not exceeding 5% of the total volume of the solution is added and heated to 60-100°C for decolorization for 10-180 minutes, and after the decolorization is completed, it is filtered while hot, and the clear liquid is cooled to 10-40°C to allow the long-chain dibasic acid to crystallize and precipitate, and the product is collected by centrifugation or plate and frame filtration, and washed with distilled water for multiple times, and dried to obtain the finished product. Due to the complex components and high viscosity of the fermentation broth, the above method requires first adding an excess of alkali to the fermentation broth to adjust the pH to 7-11, separating impurities such as bacteria, and then adding acid to adjust the pH to 2-5 to acidify and crystallize the dibasic acid. On the one hand, the input of alkali and acid increases the production cost, and on the other hand, acid-base salt formation increases the manpower and material costs of the post-treatment process. In addition, the desalination process is highly complex and improper handling will have an adverse impact on the environment.

[0006] Therefore, how to reduce the salt content in the fermentation liquid as much as possible while ensuring the acid production of sebacic acid by biological fermentation, bringing convenience to the subsequent processing process without increasing environmental pressure, is a very practical problem that needs to be solved urgently in the existing technology. Summary of the invention

[0007] A main object of the present invention is to provide a method for extracting sebacic acid, the method comprising the following steps:

[0008] (1) using acid or alkali to adjust the fermentation liquid obtained in the process of producing sebacic acid by microbial fermentation to obtain a first mixed liquid having a viscosity of 100 to 200 centipoise at 60 to 65° C.;

[0009] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90 to 95° C. and a viscosity of 30 to 50 centipoise, and keeping the temperature for ≥30 minutes;

[0010] (3) filtering the second mixed solution to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, solid-liquid separation, and purification treatment to obtain a sebacic acid product.

[0011] One embodiment of the present invention provides a sebacic acid prepared by the above method, wherein the sebacic acid has a content of ≥99.8%, a moisture content of <0.2%, an ash content of <20ppm, an iron ion content of <3ppm, a nitrogen content of <30ppm, and a color / transmittance of 440nm / 550nm>96 / 98.

[0012] The method for extracting sebacic acid according to one embodiment of the present invention can reduce acid and alkali consumption and the content of inorganic salts in water, and reduce the load of sewage treatment. In addition, the sebacic acid obtained has high purity, low impurity content, good light transmittance, etc., which is more conducive to improving the quality of downstream high-end products. DETAILED DESCRIPTION

[0013] Typical embodiments that embody the features and advantages of the 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" and "second" are used to distinguish between multiple processes with the same name, but not to limit them.

[0014] An embodiment of the present invention provides a method for extracting sebacic acid, the method comprising the following steps:

[0015] (1) using acid or alkali to adjust the fermentation liquid obtained in the process of producing sebacic acid by microbial fermentation to obtain a first mixed liquid having a viscosity of 100 to 200 centipoise at 60 to 65° C.;

[0016] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90 to 95° C. and a viscosity of 30 to 50 centipoise, and keeping the temperature for ≥30 minutes;

[0017] (3) filtering the second mixed solution to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, solid-liquid separation, and purification treatment to obtain a sebacic acid product.

[0018] In step (1) of one embodiment, the alkali may be sodium hydroxide, potassium hydroxide, aqueous ammonia, liquid ammonia, ammonia gas, or a mixed alkali containing at least two of them.

[0019] In step (1) of one embodiment, the acid may be sulfuric acid, hydrochloric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, trifluoromethanesulfonic acid, or a mixed acid containing at least two of them.

[0020] In step (1) of one embodiment, when the fermentation broth obtained during the production of sebacic acid by microbial fermentation is regulated with acid or alkali, the fermentation broth is heated.

[0021] In step (1) of one embodiment, the pH value of the first mixed solution is 5.4-5.6, for example, 5.4, 5.5, 5.6.

[0022] In step (1) of one embodiment, the fermentation liquid obtained in the process of producing sebacic acid by microbial fermentation is regulated with acid or alkali, and the fermentation liquid is heated to obtain a first mixed liquid with a viscosity of 150 to 170 centipoise at a temperature of 60 to 65°C.

[0023] In some embodiments, step (3) includes acidifying and crystallizing the filtrate to obtain a solid-liquid mixture; performing solid-liquid separation on the solid-liquid mixture to obtain a solid after solid-liquid separation, wherein the solid includes sebacic acid particles; and then refining the solid to obtain a sebacic acid product.

[0024] In the present invention, the sebacic acid fermentation broth can be a fermentation broth obtained by a method of producing sebacic acid by microbial fermentation using alkanes, fatty acids and their derivatives as fermentation substrates; wherein the microorganisms can convert the terminal methyl groups of alkanes, fatty acids and fatty acid derivatives into carboxyl groups by oxidation, thereby generating sebacic acid. In some preferred embodiments, the fermentation substrate is decane.

[0025] The method for extracting sebacic acid according to one embodiment of the present invention is particularly suitable for producing sebacic acid by fermentation under acidic conditions to obtain sebacic acid fermentation broth, wherein the acidic conditions refer to a fermentation system having a pH of 7.0 or less during the fermentation conversion period (ie, the acid production period).

[0026] In some embodiments, the sebacic acid fermentation broth is obtained by the following steps: fermenting and culturing sebacic acid-producing microorganisms, controlling the pH of the fermentation system to be above 3.0 during the bacterial growth phase and below 7.0 during the conversion phase.

[0027] In some preferred embodiments, the pH value of the fermentation system during the bacterial growth phase is preferably 3.5 to 6.5.

[0028] In some preferred embodiments, the pH value of the fermentation system during the conversion phase is preferably 4.0 to 6.8, more preferably 5.0 to 6.5.

[0029] In some embodiments, the fermentation temperature is 28-32° C., the fermentation air volume is 0.3-0.7 vvm, and the fermentation pressure is 0.05-0.14 MPa.

[0030] In some embodiments, the sebacic acid-producing microorganism comprises Candida viswanathii, Candida tropicalis, or Candida sake.

[0031] In some preferred embodiments, when the optical density (OD620) of the fermentation system is above 0.5 (30-fold dilution), for example 0.5, 0.6, 0.7, 0.8, etc., the pH of the fermentation system is controlled to be 4.0-6.8, more preferably 5.0-6.5.

[0032] In some embodiments, sebacic acid fermentation broth is obtained by the following steps:

[0033] ① Shaking culture: inoculate a glycerol tube of Candida viswanathii, Candida tropicalis or Candida sake into a seed bottle containing YPD liquid medium (containing the following ingredients (w / v): 2% glucose, 1% yeast extract, 2% peptone), with natural pH, temperature controlled at 28-32°C, shaking speed at 200-350 rpm, and culture for 10-48 hours.

[0034] ② Seed tank culture: take the above-mentioned shake flask seeds and place them in a seed tank filled with seed culture medium, control the temperature at 28-32°C, ventilation at 0.3-0.7vvm, tank pressure at 0.05-0.14MPa, and culture for 15-30h until the seeds mature. The standard for seed maturity is that the optical density (OD620) of bacterial growth after the seed solution is diluted 30 times is above 0.5, and more preferably OD620 is 0.5-1.0. The seed culture medium contains the following components (w / v): 1.0%-3.0% sucrose, 0.1%-0.5% urea, 0.1%-1.0% yeast extract, 0.2%-1.0% corn steep liquor, and 0.4%-1.2% potassium dihydrogen phosphate.

[0035] ③ Fermentation tank culture: The seed liquid obtained from the seed tank culture is inoculated into a fermentation tank containing a fermentation medium, with an inoculation amount of 10-30% (v / v, relative to the starting volume of the fermentation), and 0-10% (v / v, relative to the starting volume of the fermentation) of the fermentation raw material n-decane is added at the beginning of the fermentation. The temperature of the fermentation process is controlled at 28-32°C, the ventilation volume is 0.3-0.7vvm, the tank pressure (gauge pressure) is 0.05-0.14MPa, and a certain stirring speed is maintained, and the dissolved oxygen is controlled to be not less than 10%. The pH value of the fermentation system during the bacterial growth period is controlled to be 3.5-6.5; the pH value of the fermentation system during the fermentation conversion period is 5.0-6.5, until the fermentation is completed, and a fermentation liquid containing sebacic acid is obtained. Preferably, when the bacterial growth optical density (OD620) is ≥0.5 (diluted 30 times), the pH of the fermentation system is controlled to be 4.0-6.8, more preferably 5.0-6.5. The fermentation medium comprises the following components (w / v): 2.0% to 5.0% glucose, 0.1% to 1.0% yeast extract, 0.2% to 1.0% corn steep liquor, 0.1% to 1% potassium nitrate, 0.1% to 1.0% potassium dihydrogen phosphate and 0.1% to 0.5% ammonium sulfate.

[0036] In the method for extracting sebacic acid according to one embodiment of the present invention, in step (1), the temperature of the first mixed solution is 60-65°C, for example, 61°C, 62°C, 63°C, 64°C, etc.; the viscosity of the first mixed solution is 100-200 centipoise, for example, 120, 130, 140, 150, 160, 170, 180, 190 centipoise, preferably 120-180 centipoise.

[0037] In step (1) of one embodiment, the concentration of sebacic acid in the fermentation broth is 2 to 15 wt %, preferably 10 to 14 wt %. The concentration of sebacic acid in the fermentation broth can be adjusted by dilution or concentration.

[0038] In step (2) of one embodiment, the temperature of the second mixed solution is 90-95°C, such as 91°C, 92°C, 93°C, 94°C; the temperature is kept for ≥30 minutes, such as 40 minutes, 50 minutes, 60 minutes, 70 minutes, preferably 30-100 minutes. The viscosity of the second mixed solution is 30-50 centipoise, such as 30, 35, 40, 45, 50 centipoise.

[0039] In step (3) of one embodiment, the filtration is used to remove impurities such as bacteria and large proteins in the second mixed solution. The filtration can be centrifugal filtration or membrane filtration, preferably membrane filtration.

[0040] In step (3) of one embodiment, the filtration membrane used in the membrane filtration treatment may be a ceramic membrane, a metal membrane, a hollow fiber membrane or a plate membrane.

[0041] In step (3) of one embodiment, the filtration membrane used in the membrane filtration treatment is a ceramic membrane. When the ceramic membrane is used for membrane filtration, the operating pressure is preferably 0.1-0.6 MPa, further 0.2-0.4 MPa, such as 0.22 MPa, 0.25 MPa, 0.3 MPa, 0.35 MPa, 0.38 MPa, etc. The pore size of the filtration membrane core is preferably 0.05-0.2 microns, and more preferably 0.05-0.1 microns.

[0042] In step (3) of one embodiment, the membrane filtration temperature is 45-95°C, for example, 50°C, 52°C, 55°C, 58°C, 60°C, 70°C, 80°C, 90°C, 95°C.

[0043] In step (3) of one embodiment, the filtrate is further subjected to a decolorization treatment, which includes a step of adding a decolorizing agent to the filtrate to remove impurities such as pigments in the filtrate, and a step of separating the decolorizing agent. The decolorizing agent may include one or more of activated carbon, activated clay or diatomaceous earth. Preferably, activated carbon is added to the filtrate for decolorization.

[0044] In one embodiment, activated carbon is used for decolorization, and the amount of activated carbon added is 0.1 to 10 wt % of the sebacic acid content in the filtrate, and preferably 1 to 5 wt %.

[0045] In one embodiment, activated carbon is used for decolorization, and the temperature of the filtrate during the decolorization process is controlled to be 50-100° C., and can further be 60-80° C., such as 65° C., 70° C., 75° C., 80° C., 85° C., 90° C., 95° C. The decolorization time is 10-180 minutes, and can further be 15-120 minutes, such as 20 minutes, 25 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, 150 minutes.

[0046] In one embodiment, after the decolorization treatment, the decolorizing agent is preferably separated by plate and frame filtration, chamber filtration, centrifugal filtration, membrane filtration, etc. to obtain a decolorized solution and perform the subsequent step (3) of acidification and crystallization.

[0047] In step (3) of one embodiment, the acidification crystallization comprises: adjusting the pH value of the filtrate or the solution obtained after the filtrate is decolorized to 2-4, heating to 90-98°C for insulation, the insulation time is ≥30 minutes, and then cooling to 30-40°C to precipitate crystals to achieve recrystallization. The insulation time can be, for example, 40 minutes, 50 minutes, 60 minutes, 70 minutes, preferably 30-100 minutes.

[0048] In step (3) of one embodiment, the pH value of the solution system can be adjusted to 2, 2.2, 2.5, 2.6, 2.8, 3, 3.2, 3.5, 3.8, etc. during the acidification crystallization process.

[0049] In step (3) of one embodiment, the acid used to adjust the pH value may include an inorganic acid and / or an organic acid, such as sulfuric acid, hydrochloric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid and trifluoromethanesulfonic acid or a mixed acid containing at least two of them.

[0050] In step (3) of one embodiment, the solution after adjusting the pH value may be heated to 90-98° C., for example, 91° C., 92° C., 93° C., 94° C., 95° C., 96° C., 97° C., etc.

[0051] In step (3) of one embodiment, the temperature of the heated solution may be lowered to 30-40° C., such as 31° C., 32° C., 33° C., 34° C., 35° C., 36° C., 38° C., etc., to precipitate crystals.

[0052] In step (3) of one embodiment, solid-liquid separation may include filtration, centrifugal separation, such as plate and frame filtration, chamber filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0053] In step (3) of one embodiment, the separated solids can be washed, dried, and then subjected to subsequent refining treatment. The solids mainly include sebacic acid particles, which have stable quality and high purity, and can already meet some market demands.

[0054] In step (3) of one embodiment, the solids after solid-liquid separation are washed with water, for example, the solids after plate and frame filtration are washed with water, and then subjected to subsequent refining treatment.

[0055] In one embodiment of the present invention, the fermentation liquid obtained in the process of producing sebacic acid by microbial fermentation is regulated by using acid or alkali to obtain a first mixed liquid with a viscosity of 100 to 200 centipoise at a temperature of 60 to 65°C, and then the first mixed liquid is heated and kept warm. Not only can the sebacic acid precipitated in the fermentation liquid be converted into salts and dissolved in the fermentation liquid by using very little acid or alkali, but also the secondary precipitation of sebacic acid salts can be avoided under the premise of reducing the amount of dilution water. In this state, impurities such as bacteria can be removed by filtering treatment, and then acidification and crystallization can be carried out, which can further reduce the consumption of acid, and at the same time greatly reduce the content of inorganic salts in the wastewater while increasing the yield of sebacic acid, overcome the problem of high inorganic salt content in water in existing treatment processes, and reduce the load of sewage treatment.

[0056] In one embodiment of the present invention, the improvement of the solid quality after solid-liquid separation can also reduce the operation steps of subsequent refining treatment to obtain a higher purity sebacic acid product, further improve the product yield, and reduce production costs; in addition, it can also reduce equipment investment.

[0057] In step (3) of one embodiment, the refining treatment comprises:

[0058] The solid obtained after solid-liquid separation is mixed with an organic solvent at a temperature of 75 to 95° C. to obtain a mixture;

[0059] subjecting the mixture to a decolorization treatment to obtain a second mixture;

[0060] subjecting the second mixture to crystallization to obtain a second solid-liquid mixture; and

[0061] performing solid-liquid separation on the second solid-liquid mixture;

[0062] Wherein, the organic solvent is selected from one or more of organic acids, alcohols, esters and alkanes.

[0063] In step (3) of one embodiment, the solid obtained after solid-liquid separation is washed, dried and then purified.

[0064] In step (3) of one embodiment, the organic solvent may be one or more of an organic acid, alcohol, ester, and alkane that do not react with sebacic acid. Here, "does not react with sebacic acid" means that during the heating and heat preservation process of the refining treatment, the weight of sebacic acid that reacts with the organic solvent accounts for ≤1% of the total weight of sebacic acid.

[0065] In step (3) of one embodiment, the organic solvent may be any one or more of acetic acid, (C1-C4) alcohol acetate, and C3-C8 alcohol, such as methyl acetate, ethyl acetate, n-propanol, isopropanol, n-butanol, etc. Preferably, it is acetic acid.

[0066] In step (3) of one embodiment, the purity of the organic solvent is ≥95%, further ≥97%, and further ≥99%.

[0067] In step (3) of one embodiment, the mass ratio of the solid to the organic solvent is 1:(2.2-2.5), for example, 1:2.2, 1:2.3, 1:2.4, etc.

[0068] In step (3) of one embodiment, the mixture of solid organic solvent is decolorized to remove impurities; the decolorizer may be the same as the decolorizer in step (1) or different. The decolorizer may be activated carbon, and the amount of activated carbon may be 0.1 to 10 wt%, preferably 1 to 5 wt%, based on the weight of sebacic acid contained in the first-stage sebacic acid product solution; for example, the amount of activated carbon may be 0.5 wt%, 1 wt%, 1.5 wt%, 2 wt%, 2.5 wt%, 3 wt%, 3.5 wt%, 4 wt%, 4.5 wt%, etc.

[0069] In step (3) of one embodiment, during the decolorization process, the temperature of the solution can be 50-100° C., and can further be 60-80° C., such as 65° C., 70° C., 75° C., 80° C., 85° C., 90° C., 95° C. The decolorization time can be 10-180 minutes, and can further be 15-120 minutes, such as 20 minutes, 25 minutes, 30 minutes, 40 minutes, 45 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, 150 minutes. After the decolorization, the decolorizing agent is preferably separated by plate and frame filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0070] In step (3) of one embodiment, the mixture can be cooled to precipitate sebacic acid crystals. The end point of the cooling crystallization can be 20-30°C, such as 22°C, 23°C, 25°C, 26°C, 28°C, etc.

[0071] In step (3) of one embodiment, the second solid-liquid mixture obtained after crystallization can be subjected to solid-liquid separation, and the solid-liquid separation can be carried out by plate and frame filtration, chamber filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0072] In step (3) of one embodiment, the solid obtained by solid-liquid separation can be washed with water and dried to obtain the sebacic acid product.

[0073] In step (3) of one embodiment, the purification treatment may be performed twice or more.

[0074] In one embodiment, the method further comprises a step (4) performed after step (3), wherein the step (4) comprises: placing the sebacic acid product obtained after the refining treatment in step (3) in water at 90 to 110° C., keeping the temperature for 15 to 150 minutes, cooling the water to a terminal temperature of 20 to 65° C. after the insulation, and then performing a solid-liquid separation treatment.

[0075] Step (4) of one embodiment of the present invention comprises: placing the sebacic acid product obtained in step (3) into a crystallization tank, adding water, wherein the mass fraction of sebacic acid in water is 10 to 40 wt %, controlling the temperature of the aqueous solution to 95 to 105° C., and holding the solution for 15 to 150 minutes. After the holding is completed, the temperature is lowered to an end point temperature of 20 to 65° C., and then solid-liquid separation is performed by centrifugal filtration, plate and frame filtration, drum filtration, etc. to obtain sebacic acid; and the sebacic acid after solid-liquid separation is washed with water.

[0076] In one embodiment, the water-washed sebacic acid is dried, and the drying method includes but is not limited to any one or a combination of paddle drying, airflow drying or belt drying to finally obtain a sebacic acid product with high purity and low impurity content.

[0077] The extraction method of sebacic acid according to one embodiment of the present invention can remove bacteria by membrane filtration under low pH conditions, which can reduce acid and alkali consumption and the content of inorganic salts in water, and reduce the load of sewage treatment; at the same time, an intermediate product with low impurity content and high purity (i.e., the solid material of the present invention) can be obtained, and a high-end sebacic acid product can be obtained by further refining.

[0078] The extraction method of one embodiment of the present invention can improve the quality and purity of sebacic acid products, is simple and easy to operate, and is conducive to large-scale industrial production.

[0079] The extraction method of one embodiment of the present invention has a product with high purity, good light transmittance, and higher quality index than sebacic acid produced by chemical method, which is more conducive to improving the quality of downstream products.

[0080] The sebacic acid content obtained in one embodiment of the present invention is ≥99.8%, the moisture content is <0.2%, the ash content is <20ppm, the iron ion content is <3ppm, the nitrogen content is <30ppm, and the color / transmittance 440nm / 550nm>96 / 98.

[0081] The following is a detailed description of the method for extracting sebacic acid according to one embodiment of the present invention in conjunction with a specific example. Wherein, unless otherwise specified, all raw materials used can be obtained from commercial sources, and the details of the related tests involved are as follows.

[0082] 1. Viscosity of fermentation broth: measured using a capillary viscometer.

[0083] 2. Sebacic acid content (purity): Take the sample to be tested and perform conventional gas chromatography pretreatment, gas chromatography detection, and calculate the sebacic acid content based on the sebacic acid peak area.

[0084] 3. Moisture content: Loss on drying method, when the sample is heated to constant weight at 105℃, the proportion of volatile matter lost in the sample is the percentage of the sample.

[0085] 4. Ash content: Take the sample to be tested and burn it in a crucible, then burn it in a muffle furnace at 700-800℃ for 2 hours. After cooling to constant weight, measure the weight and calculate the percentage of the sample weight.

[0086] 5. Nitrogen content determination: measured by Kjeldahl method.

[0087] 6. Determination of iron ion content: The iron salt content (ppm) in terms of Fe in the sample was determined using the o-phenanthroline method.

[0088] 7. Color / transmittance: Take a 25% dimethyl sulfoxide solution of the sample to be tested and use a spectrophotometer to detect its transmittance at 440nm and 550nm. For example, "color / transmittance 440nm / 550nm>96 / 98" means that the transmittance at 440nm>96 and at 550nm>98.

[0089] 8. Total alkali consumption (T / T): The total alkali consumption during fermentation and extraction process for producing one ton of sebacic acid in the following examples and comparative examples.

[0090] Example 1

[0091] Production of Sebacic Acid Fermentation Broth by Microbial Fermentation

[0092] The strain used in the fermentation was Candida tropicalis CAT H1614, which was deposited in China Center for Type Culture Collection (CCTCC), Wuhan University, Wuhan, China, with a deposit number of CCTCC NO: M 2013143.

[0093] 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 fermentation medium is 0.7%, the fermentation is carried out 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%), and the inoculation amount is 20% (v / v). The fermentation temperature is controlled at 30°C, the ventilation volume is 0.3vvm, the tank pressure is 0.08MPa, a certain stirring speed is maintained, and the dissolved oxygen is maintained above 20% during the fermentation process. The initial fermentation pH is about 6.5, and the pH of the fermentation liquid gradually decreases with the growth of the microorganisms. The pH of the fermentation system is controlled to be 4.0 during the growth period of the microorganisms. When the optical density (OD620) of the microorganisms 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 when the fermentation cycle is 10 to 20 hours, and the decane content in the fermentation liquid is controlled to be 3 to 5%. When the decane in the fermentation liquid is detected to be 0, the fermentation is stopped. The fermentation time is 162 hours, and a fermentation liquid containing sebacic acid is obtained, the sebacic acid content is 176 g / L, and the viscosity is 515 centipoise.

[0094] Extraction of Sebacic Acid

[0095] (1) adjusting the fermentation liquid obtained by the above fermentation method (the concentration of sebacic acid is 5 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid with a temperature of 62° C., a viscosity of 158 centipoise, and a pH of 5.4;

[0096] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 31 centipoise, and keeping the temperature for 30 minutes;

[0097] (3) filtering the second mixed solution to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, solid-liquid separation, and refining treatment to obtain a sebacic acid product; wherein:

[0098] a) The filtration is membrane filtration to remove impurities such as bacteria, wherein a ceramic membrane with a core pore size of 0.05 microns is used for membrane filtration, the operating pressure is 0.5 MPa, and the temperature during membrane filtration is 90° C.; an activated carbon decolorizer with a sebacic acid content of 5 wt% is added to the solution obtained after filtration, and the solution is decolorized at 65° C. for 50 minutes, and then the decolorizer is separated by centrifugation to obtain a filtrate;

[0099] b) subjecting the filtrate obtained in step a) to an acidification crystallization treatment to obtain a solid-liquid mixture; wherein, during the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.5, the temperature is raised to 95° C. and kept warm for 40 minutes, and then the temperature is lowered to 35° C. to precipitate crystals, and solids are obtained after solid-liquid separation by plate and frame filtration, and the solids are washed with deionized water;

[0100] c) mixing the solid with acetic acid (purity 95%) to obtain a mixture, wherein the mass ratio of the solid to the acetic acid is 1:2.2, adding 4wt% activated carbon to the solid for decolorization, controlling the solution temperature to 80°C, decolorizing for 45 minutes, and removing the decolorizer by centrifugation to obtain a second mixture; cooling the second mixture to 30°C for crystallization to obtain a second solid-liquid mixture; using plate and frame filtration to separate the solid and liquid of the second solid-liquid mixture, and washing the obtained solid with deionized water and drying to obtain a sebacic acid product.

[0101] Example 2

[0102] Example 2 uses substantially the same raw materials and methods as Example 1, with the only difference being:

[0103] (1) adjusting the fermentation liquid obtained by the above fermentation method (the concentration of sebacic acid is 10 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid with a temperature of 62° C., a viscosity of 161 centipoise, and a pH of 5.4;

[0104] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 35 centipoise, and maintaining the temperature for 30 minutes.

[0105] Example 3

[0106] Example 3 uses substantially the same raw materials and methods as Example 1, with the only difference being:

[0107] (1) adjusting the fermentation liquid obtained by the above fermentation method (the concentration of sebacic acid is 12 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid with a temperature of 62° C., a viscosity of 165 centipoise, and a pH of 5.4;

[0108] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 40 centipoise, and maintaining the temperature for 30 minutes.

[0109] Example 4

[0110] Example 4 uses substantially the same raw materials and methods as Example 1, with the only difference being:

[0111] (1) adjusting the fermentation liquid obtained by the above fermentation method (the concentration of sebacic acid is 13 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid with a temperature of 62° C., a viscosity of 168 centipoise, and a pH of 5.4;

[0112] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 46 centipoise, and maintaining the temperature for 30 minutes.

[0113] Example 5

[0114] Example 5 uses substantially the same raw materials and methods as Example 1, with the only difference being:

[0115] (1) adjusting the fermentation liquid obtained by the above fermentation method (the concentration of sebacic acid is 15 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid with a temperature of 62° C., a viscosity of 176 centipoise, and a pH of 5.4;

[0116] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 48 cps, and maintaining the temperature for 30 minutes.

[0117] Example 6

[0118] Example 6 uses substantially the same raw materials and methods as Example 3, with the only difference being:

[0119] (1) adjusting the fermentation liquid obtained by the above fermentation method (the concentration of sebacic acid is 12 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid with a temperature of 65° C., a viscosity of 160 centipoise, and a pH of 5.5;

[0120] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 95° C. and a viscosity of 41 centipoise, and maintaining the temperature for 30 minutes.

[0121] Example 7

[0122] Example 7 uses substantially the same raw materials and methods as Example 3, with the only difference being that: after step c), step d) is further included: the solid sebacic acid product obtained in step c) is placed in a crystallization tank, water is added, the mass fraction of sebacic acid in water is 40wt%, the water temperature is 100°C, the insulation time is 35 minutes, and then the temperature is lowered to an end point temperature of 20°C, and then the solid-liquid separation is carried out by chamber filtration; the sebacic acid after solid-liquid separation is washed with 3 times the mass of deionized water to obtain a sebacic acid product.

[0123] Comparative Example 1

[0124] (1) adjusting the fermentation liquid obtained in Example 1 (the concentration of sebacic acid is 10 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid having a temperature of 60° C., a viscosity of 155 centipoise, and a pH of 9;

[0125] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 30 centipoise, and keeping the temperature for 30 minutes;

[0126] (3) filtering the second mixed solution to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, solid-liquid separation, and refining treatment to obtain a sebacic acid product; wherein:

[0127] a) The filtration is membrane filtration to remove impurities such as bacteria, wherein a ceramic membrane with a core pore size of 0.05 microns is used for membrane filtration, the operating pressure is 0.5 MPa, and the temperature during membrane filtration is 90° C.; an activated carbon decolorizer with a sebacic acid content of 5 wt% is added to the solution obtained after filtration, and the solution is decolorized at 65° C. for 50 minutes, and then the decolorizer is separated by centrifugation to obtain a filtrate;

[0128] b) subjecting the filtrate obtained in step a) to an acidification crystallization treatment to obtain a solid-liquid mixture; wherein, during the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.5, the temperature is raised to 95° C. and kept warm for 40 minutes, and then the temperature is lowered to 35° C. to precipitate crystals, and solids are obtained after solid-liquid separation by plate and frame filtration, and the solids are washed with deionized water;

[0129] c) mixing the solid with acetic acid (purity 95%) to obtain a mixture, wherein the mass ratio of the solid to the acetic acid is 1:2.2, adding 4wt% activated carbon to the solid for decolorization, controlling the solution temperature to 80°C, decolorizing for 45 minutes, and removing the decolorizer by centrifugation to obtain a second mixture; cooling the second mixture to 30°C for crystallization to obtain a second solid-liquid mixture; using plate and frame filtration to separate the solid and liquid of the second solid-liquid mixture, and washing the obtained solid with deionized water and drying to obtain a sebacic acid product.

[0130] Comparative Example 2

[0131] Comparative Example 2 uses substantially the same raw materials and methods as Comparative Example 1, with the only difference being that step (3) includes two refining treatment processes, i.e., the sebacic acid product obtained in step (3) of Comparative Example 1 is subjected to the steps of mixing the solid with acetic acid (purity 95%) as described in step (3) c) again.

[0132] Comparative Example 3

[0133] Comparative Example 3 uses substantially the same raw materials and methods as Example 1, except that:

[0134] (1) adjusting the fermentation liquid obtained in Example 1 (the concentration of sebacic acid is 10 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid having a temperature of 70° C., a viscosity of 183 centipoise, and a pH of 5.3;

[0135] (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90° C. and a viscosity of 52 centipoise, and keeping the temperature for 30 minutes;

[0136] Comparative Example 4

[0137] Comparative Example 4 uses the same raw materials as Example 1, and the specific process is as follows:

[0138] (1) adjusting the fermentation liquid obtained in Example 1 (the concentration of sebacic acid is 10 wt %) using sulfuric acid and sodium hydroxide to obtain a first mixed liquid having a temperature of 65° C., a viscosity of 156 centipoise, and a pH value of 5.4, and then keeping the mixture warm for 30 minutes;

[0139] (2) filtering the first mixed solution to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, solid-liquid separation, and refining treatment to obtain a sebacic acid product; wherein the specific parameters used in the filtration, acidification, crystallization, solid-liquid separation, and refining treatment are the same as those in step (3) of Example 1.

[0140] Table 1 lists the test data of the sebacic acid products obtained in Examples 1 to 7 and Comparative Examples 1 to 4.

[0141] Table 1

[0142]

[0143]

[0144] As can be seen from the results in the above table, the sebacic acid product of the present invention has better product performance than the sebacic acid product produced by conventional chemical method, especially in terms of water content, total nitrogen impurity content, etc., so that the quality and performance of the polymer product can be further improved when the polymer is prepared later. The sebacic acid product and extraction method of the present invention make the sebacic acid prepared by biological method have better application potential, and provide the possibility of industrially replacing the sebacic acid product of chemical method.

[0145] The sebacic acid used in one embodiment of the present invention is obtained by microbial fermentation, and by the processing of microbial fermentation process and separation and purification process, under the premise of greatly reducing the consumption of acid and alkali, high purity (i.e. high sebacic acid content) is still obtained, and moisture, ash, iron ion, nitrogen impurity content are low, and the sebacic acid product with high light transmittance is obtained. The sebacic acid product with high purity and low impurity content can meet the quality requirements of products such as high-grade polyamide and polyester, and the polymer product performance obtained is more excellent. Moreover, the extraction method of the sebacic acid of one embodiment of the present invention is mild in condition, environmentally friendly, and the product conversion rate is high and of good quality, and chemical method can be substituted for the industrial scale production of sebacic acid product.

[0146] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0147] 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 sebacic acid, characterized in that: The method comprises the following steps: (1) using an acid or alkali to adjust the fermentation liquid obtained in the process of producing sebacic acid by a microbial fermentation method to obtain a first mixed liquid having a viscosity of 100 to 200 centipoise at 60 to 65° C.; (2) heating the first mixed solution to obtain a second mixed solution having a temperature of 90 to 95° C. and a viscosity of 30 to 50 centipoise, and maintaining the temperature for ≥30 minutes; (3) filtering the second mixed solution to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, solid-liquid separation, and purification treatment to obtain a sebacic acid product; Wherein, the pH value of the first mixed solution is 5.4-5.

6.

2. The method according to claim 1, characterized in that: The concentration of sebacic acid in the fermentation broth is 2-15 wt %.

3. The method according to claim 1, characterized in that In the process of producing sebacic acid by the microbial fermentation method, the pH of the fermentation system during the bacterial growth phase is controlled to be above 3.0, and the pH of the fermentation system during the conversion phase is controlled to be below 7.

0.

4. The method according to claim 3, characterized in that The pH value of the fermentation system during the conversion period is 4.0-6.

8.

5. The method according to claim 4, characterized in that The pH value of the fermentation system during the conversion period is 5.0-6.

5.

6. The method according to claim 1, characterized in that The filtration is membrane filtration, and the membrane used in the membrane filtration is selected from a ceramic membrane, a metal membrane, a hollow fiber membrane or a plate membrane; Wherein, when a ceramic membrane is used for the membrane filtration, the operating pressure is 0.1-0.6 MPa, and the pore size of the filter membrane core is 0.05-0.2 microns.

7. The method according to claim 1, characterized in that The acidification crystallization comprises: adjusting the pH value of the filtrate to 2-4, heating the filtrate to 90-98° C., and then cooling the filtrate to 30-40° C.

8. The method according to claim 1, characterized in that The refining process comprises: The solid obtained after solid-liquid separation is mixed with an organic solvent at a temperature of 75 to 95° C. to obtain a mixture; subjecting the mixture to a decolorization treatment to obtain a second mixture; subjecting the second mixture to crystallization to obtain a second solid-liquid mixture; and performing solid-liquid separation on the second solid-liquid mixture; Wherein, the organic solvent is selected from one or more of organic acids, alcohols, esters and alkanes.

9. The method according to claim 8, characterized in that The mass ratio of the solid matter to the organic solvent is 1:2.2-2.

5.

10. The method according to claim 1, characterized in that The method also includes placing the solid obtained after the refining treatment in water at a temperature of 90 to 110° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation treatment.

11. The method according to claim 1, characterized in that: The sebacic acid product has a sebacic acid content of ≥99.8%, a moisture content of <0.2%, an ash content of <20ppm, an iron ion content of <3ppm, a nitrogen content of <30ppm, and a color / transmittance of 440nm / 550nm>96 / 98.

Images