Method for extracting and refining long-chain dibasic acid and product

Abstract

The present invention provides a method for extracting and refining a long-chain dibasic acid and a product. The method comprises the following steps: (1) heating a fermentation broth of a long-chain dibasic acid to reduce the content of insolubles in the fermentation broth, so as to obtain a mixed material liquid having a dry weight proportion of insolubles not exceeding 4 wt%; (2) filtering the mixed material liquid to obtain a filtrate, carrying out acidification crystallization treatment and solid-liquid separation treatment on the filtrate with or without decolorization treatment to obtain a first solid; and (3) carrying out refining treatment on the first solid. The extraction and refining method of the present invention can improve the purity and quality of long-chain dibasic acid products and yield products having a large particle size, is simple and easy to operate, and is conducive to large-scale industrial production.

Description

Extraction and refining method of long-chain dibasic acid and product thereof TECHNICAL FIELD

[0001] The present application relates to the extraction and refining of long-chain dibasic acid, in particular to a method for extracting and refining long-chain dibasic acid from long-chain dibasic acid fermentation broth produced by microbial fermentation. BACKGROUND

[0002] Long-chain dibasic acid generally refers to aliphatic dicarboxylic acid (abbreviated as DCn, n≥10) containing more than 10 carbon atoms in the carbon chain, which is a fine chemical product with important and wide industrial applications, and is an important raw material for synthesizing high-grade fragrances, high-performance engineering plastics, high-temperature dielectrics, high-grade hot melt adhesives, cold-resistant plasticizers, high-grade lubricating oils, high-grade paints and coatings, etc. in the chemical industry. The production methods of long-chain dibasic acid mainly include chemical synthesis and biological fermentation.

[0003] Biological fermentation method for producing long-chain dibasic acid is the application of microbial fermentation technology in the field of petrochemical industry in the 1970s, which generally uses wax oil, a byproduct of petroleum, as raw material. The biological fermentation method has the advantages of wide raw material sources, simple production process, and mild production conditions. The long-chain dibasic acid in the fermentation broth prepared by the biological fermentation method exists in the form of salt and / or acid. The fermentation broth usually contains other carbon chain length dibasic acids, monobasic acids, hydroxy acids and other impurities such as pigments, inorganic salts and nitrogen-containing compounds, which are not the main products. By extracting long-chain dibasic acid from the fermentation broth, a product with a certain purity can be obtained. According to different application fields and customer needs, the long-chain dibasic acid product extracted from the fermentation broth can be further refined.

[0004] SUMMARY

[0005] One main purpose of the present application is to provide an extraction and refining method of long-chain dibasic acid, which comprises the following steps:

[0006] (1) heating the long-chain dibasic acid fermentation broth to reduce the content of insoluble substances in the fermentation broth, to obtain a mixed liquor with a dry weight ratio of insoluble substances of 4wt% or less;

[0007] (2) filtering the mixed liquor to obtain a filtrate, and then performing acidification crystallization treatment and solid-liquid separation treatment on the filtrate with or without decolorization treatment, to obtain a first solid;

[0008] (3) refining the first solid.

[0009] Optionally, the base is added before, during or after the heating treatment in step (1). The base includes sodium hydroxide, potassium hydroxide, aqueous ammonia, liquid ammonia or a mixture of at least two of them. The base is in the form of solid, solution or solid-liquid mixture. The base includes sodium hydroxide, potassium hydroxide, aqueous ammonia, liquid ammonia, ammonia gas or a mixture of at least two of them. The base is in the form of aqueous solution with a concentration of 10wt% to 40wt%, further 15wt% to 35wt%, further 15wt% to 30wt%.

[0010] The long-chain diacid is selected from any one of decanedioic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedioic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedioic acid, 9-ene-octadecanedioic acid or a combination of two or more thereof.

[0011] The fermentation broth of long-chain diacid can be obtained by a method of fermenting alkane, fatty acid and derivatives thereof to produce long-chain diacid using microorganism. The microorganism can convert the terminal methyl group of alkane, fatty acid and derivatives thereof into carboxyl group by oxidation, thereby producing long-chain diacid. The long-chain diacid in the fermentation broth is in the form of long-chain diacid and / or long-chain diacid salt.

[0012] In the present application, the specific preparation method of the fermentation broth of long-chain diacid is not particularly limited.

[0013] In some preferred embodiments, the fermentation broth of long-chain diacid is obtained by culturing long-chain diacid-producing bacteria and controlling the pH of the fermentation system to be 2.0 or higher during the growth phase of the bacteria and 2 to 12 during the conversion phase.

[0014] In some preferred embodiments, the fermentation substrate is alkane, the fermentation temperature is 28 to 32°C, the air flow is 0.3 to 1.0vvm, the pressure is 0.05 to 0.14MPa, and the inoculation amount is 10 to 30%(v / v).

[0015] In some preferred embodiments, the long-chain diacid-producing microorganism includes Candida viswanathii, Candida tropicalis or Candida sake.

[0016] In an embodiment, the pH of the fermentation broth in step (1) is 2 to 12, further 4 to 12, further 4 to 9, further 4 to 6.5 or 7.3 to 8.5, further 5 to 6.5 or 7.5 to 8.3. For example, it can be 4.2, 5.0, 5.7, 6.5, 7.2, 8.0, 8.3.

[0017] In step (1), the pH value of the fermentation broth can be the natural pH value of the fermentation broth obtained after termination of fermentation, or the pH value after adjustment by adding acid and / or base.

[0018] In an embodiment, the pH value of the fermentation broth is adjusted to 2-12 by adding acid and / or base. The base includes sodium hydroxide, potassium hydroxide, aqueous ammonia, liquid ammonia, ammonia gas, or a mixed base containing at least two of the above. The base exists in the form of an aqueous solution, and the concentration is 10wt%-40wt%, further 15wt%-35wt%, and further 15wt%-30wt%. The acid includes sulfuric acid, hydrochloric acid, nitric acid, acetic acid, oxalic acid, phosphoric acid, trifluoromethanesulfonic acid, or a mixed acid containing at least two of the above.

[0019] In some embodiments, the fermentation broth with a pH value in the range of step (1) is obtained by adjusting the pH value of the fermentation broth of long-chain dibasic acid.

[0020] As is commonly known by those skilled in the art, the concentration of the long-chain dibasic acid in the termination fermentation broth after termination of fermentation is generally 5wt%-20wt%. The long-chain dibasic acid exists in the form of long-chain dibasic acid and / or long-chain dibasic acid salt.

[0021] In the present application, the heating temperature in step (1) is not particularly limited, as long as the fermentation broth can be heated to obtain a mixture liquid in which the dry weight percentage of insoluble substances is within the range defined in the present application.

[0022] As is commonly known by those skilled in the art, the insoluble substances in the termination fermentation broth of long-chain dibasic acid after termination of fermentation include: undissolved long-chain dibasic acid, insoluble protein, pigment, bacterial cells, inorganic salt, and miscellaneous acid.

[0023] In an embodiment, in step (1), the dry weight percentage of insoluble substances in the fermentation broth of long-chain dibasic acid is 2wt%-20wt%, further 2.5wt%-20wt%, further 3wt%-20wt%, further 3.5wt%-20wt%, and further 4.5wt%-20wt%. The dry weight percentage of insoluble substances in the fermentation broth is calculated as follows: dry weight (g) of insoluble substances in the fermentation broth / total mass (g) of the fermentation broth*100%. The insoluble substances in the fermentation broth can be separated by centrifugation or filtration.

[0024] In the present application, the content of insoluble substances in the fermentation broth is reduced by heating. The heating treatment changes the composition of the fermentation broth, the degree of suspension and the aggregation state of long-chain dibasic acid in the fermentation broth. By heating, part of the impurities in the fermentation broth denature, part of the impurities dissolve and precipitate. At the same time, heating also promotes the dissolution of long-chain dibasic acid. The present application found that after heating treatment, the fermentation broth with the above insoluble content characteristics is separated by filtration, and the impurity content in the filtrate obtained is significantly reduced, which is beneficial to the improvement of product purity.

[0025] In an embodiment, the dry weight percentage of insoluble substances in the mixed liquor in step (1) is 3 wt% or less, further 2.5 wt% or less, further 2 wt% or less, further 1.5 wt% or less.

[0026] The calculation method of the dry weight percentage of insoluble substances in the mixed liquor is as follows: the dry weight (g) of insoluble substances in the mixed liquor / the total mass (g) of the mixed liquor*100%. The insoluble substances in the mixed liquor can be separated by centrifugation or filtration.

[0027] In some embodiments, in step (2), the mixed liquor is filtered, and the filtrate or the decolorized liquid obtained after the decolorization treatment of the filtrate is subjected to acidification crystallization treatment and solid-liquid separation treatment to obtain a first solid. The first solid mainly contains long-chain dibasic acid, which has stable mass and high purity, and can already meet part of the market demand.

[0028] In step (2) of an embodiment, the filtration method is preferably membrane filtration.

[0029] In step (2) of an embodiment, the membrane used in the membrane filtration treatment is a ceramic membrane.

[0030] In step (2) of an embodiment, the operating pressure during membrane filtration is 0.1-1.2 MPa, further 0.1-1 MPa, further 0.3-0.8 MPa, for example 0.22 MPa, 0.3 MPa, 0.35 MPa, 0.4 MPa, 0.7 MPa, etc.

[0031] In step (2) of an embodiment, the pore size of the filtration membrane is 0.01-0.5 microns, further 0.01-0.2 microns, further 0.03-0.15 microns, further 0.05-0.1 microns.

[0032] In step (2) of an embodiment, the filtrate after filtration is subjected to decolorization treatment to obtain a decolorized liquid, and the decolorized liquid is subjected to acidification crystallization treatment.

[0033] As is commonly known by those skilled in the art, decolorization treatment includes the step of adding a decolorizing agent to the filtrate, and the step of separating (e.g., centrifugation or filtration) the decolorizing agent to obtain a decolorized liquid.

[0034] In one embodiment, activated carbon is used as the decoloring agent, and the iodine adsorption value of the activated carbon is 250 mg / g or more, further 500 mg / g or more, and further 600-1500 mg / g.

[0035] In one embodiment, the amount of the decoloring agent added in the decoloring treatment is 0.5%-10% of the mass of the long-chain dibasic acid contained in the liquid to be decolored (or the filtrate), further 0.5%-5%, further 1%-5%, and further 1.2%-4.8%.

[0036] In one embodiment, the temperature of the decoloring treatment is 50-100°C, and further can be 60-90°C, for example, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, 95°C.

[0037] In one embodiment, the time of the decoloring treatment is 10-180 minutes, further can be 15-120 minutes, and further can be 18-100 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, 150 minutes.

[0038] In one embodiment, after the decoloring is completed, the decoloring agent is separated by a plate-and-frame filtration, a chamber filtration, a centrifugal filtration, a membrane filtration, or the like, to obtain a decolorized liquid.

[0039] In step (2) of one embodiment, the acidification crystallization treatment includes adjusting the pH value of the filtrate or the decolorized liquid obtained after the decoloring treatment of the filtrate to 2-4, and further to 2.2-3.8, for example, 2, 2.2, 2.5, 2.6, 2.8, 3, 3.2, 3.5, 3.8.

[0040] In step (2) of one embodiment, in the acidification crystallization treatment, the acid used to adjust the pH value can 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.

[0041] In step (2) of one embodiment, a solid-liquid separation treatment is performed after the acidification crystallization treatment to obtain a first solid. The solid-liquid separation treatment can include a filtration separation, a centrifugal separation, for example, a plate-and-frame filtration, a chamber filtration, a centrifugal filtration, a vacuum negative pressure filtration, or the like.

[0042] In one embodiment, a long-chain dibasic acid product with improved quality is obtained by performing a refining treatment on the first solid.

[0043] In one embodiment, the first solid is washed and dried before the refining treatment in step (3).

[0044] In step (3) of one embodiment, the purification treatment includes any one or a combination of two or more of recrystallization, melt crystallization, extraction, distillation, chromatographic separation, and water treatment.

[0045] In step (3) of one embodiment, the purification treatment includes the following steps:

[0046] The first solid is mixed with an organic solvent, and decolorization treatment is performed at 75°C to 100°C. The decolorized solution is subjected to crystallization treatment and solid-liquid separation treatment, and a second solid is obtained.

[0047] In step (3) of one embodiment, the organic solvent includes any one or a combination of two or more of an organic acid, an alcohol, an ester, and an alkane.

[0048] In step (3) of one embodiment, the organic solvent includes any one or a combination of two or more of acetic acid, a (C1 to C4) acetic acid alcohol ester, and a C3 to C8 alcohol, such as any one or a combination of two or more of methyl acetate, ethyl acetate, n-propanol, isopropanol, and n-butanol. Acetic acid is preferred.

[0049] In step (3) of one embodiment, the organic solvent contains water, such as an acetic acid aqueous solution (or acetic acid solution).

[0050] In step (3) of one embodiment, the concentration of the organic solvent is ≥ 75%, further ≥ 79%, further ≥ 80.5%, further ≥ 85%, further ≥ 87.5%, further ≥ 89.5%, further ≥ 90%, further ≥ 90.5%, further ≥ 95%, further ≥ 97%, further ≥ 99%.

[0051] In step (3) of one embodiment, the mass ratio of the first solid to the organic solvent is 1 : (1 to 10), further 1 : (1 to 5).

[0052] In step (3) of one embodiment, activated carbon is used as the decolorizing agent in the decolorization treatment, and the iodine adsorption value of the activated carbon is 250 mg / g or more, further 500 mg / g or more, further 600 to 1500 mg / g.

[0053] The amount of the decolorizing agent can be 0.1% to 10%, further 0.5% to 5%, further 1% to 5%, further 1.2% to 4.8%, of the first solid (i.e., the solid to be decolorized before being mixed with the organic solvent).

[0054] In step (3) of one embodiment, the temperature of the decoloring treatment can be 77-100°C, further 77-98°C, further 80-98°C, for example 65°C, 70°C, 72°C, 75°C, 77°C, 80°C, 85°C, 90°C, 95°C.

[0055] In step (3) of one embodiment, the time of the decoloring treatment can be 10-180 minutes, further 15-120 minutes, for example 20 minutes, 25 minutes, 30 minutes, 40 minutes, 45 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, 150 minutes.

[0056] After the decoloring is completed, the decoloring agent can be separated by plate and frame filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0057] In step (3) of one embodiment, the crystallization treatment is a cooling crystallization treatment, and the terminal temperature of the cooling can be 20-55°C, further 20-40°C. The long-chain dibasic acid crystals are precipitated by the crystallization treatment.

[0058] In step (3) of one embodiment, a second solid is obtained by the solid-liquid separation treatment. The obtained second solid is a long-chain dibasic acid product with high purity, stable quality, and wide application field.

[0059] In step (3) of one embodiment, the solid-liquid separation treatment includes plate and frame filtration, compartment filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0060] In one embodiment, the step (3) further includes washing the second solid. For example, the second solid is washed with water and / or an organic solvent.

[0061] In one embodiment, the second solid is washed and then subjected to a drying treatment.

[0062] In one embodiment, the second solid can be further refined to improve the product quality, including the following steps: mixing the second solid with water, heating to 70-150°C, cooling to 20-65°C after not being kept warm or being kept warm for 15-150 minutes, and then performing a solid-liquid separation treatment to obtain a third solid.

[0063] In one embodiment, the mass ratio of the second solid to water can be 1:(2-20), further 1:(3-15), further 1:(3-10).

[0064] In one embodiment, the second solid is mixed with water, heated to 90-150°C, kept warm for 15-150 minutes, then cooled to 20-65°C, and then subjected to a solid-liquid separation treatment to obtain a third solid.

[0065] In one embodiment, the second solid is mixed with water, heated to 70-100°C, and maintained for 15-150 minutes, then cooled to 20-65°C, and then subjected to solid-liquid separation to obtain a third solid.

[0066] In one embodiment, the refining of the second solid includes the following steps:

[0067] S1 : the second solid is mixed with water, and the mixture is heated to 90-135°C,

[0068] S2: cooled to 20-65°C, and then subjected to solid-liquid separation to obtain a third solid.

[0069] In one embodiment, in step S1, the second solid is mixed with water, and the mixture is heated to 92-130°C, 100-110°C, or 100-120°C.

[0070] In one embodiment, in step S2, the cooling is to 20-45°C.

[0071] In one embodiment, in step S2, the equipment used for cooling is not particularly limited. For example, a heat exchange device with a heat transfer surface that can achieve heat exchange between two fluids (i.e., the hot fluid releases heat, and the cold fluid absorbs heat). The heat exchange device is, for example, a stirred tank with a jacket, in which hot fluid is added, and cold fluid is passed through the jacket. Other examples of heat exchange devices are conventional heat exchangers, such as tube heat exchangers, plate heat exchangers.

[0072] Specifically, the material to be cooled in step S2 is passed into the heat exchange device as a hot fluid, and heat exchange is performed with the cold fluid passed into the heat exchange device to achieve cooling.

[0073] In step S2, the cold fluid passed into the heat exchange device can be any component fluid. For example, water or other media, or it can be a mixture of long-chain dibasic acid solid and water, specifically, a mixture of the second solid and water.

[0074] In one specific embodiment of step S2, the material to be cooled is passed into the heat exchange device as a hot fluid, and the cold fluid passed into the heat exchange device is a mixture of another batch of the second solid and water.

[0075] In one embodiment, the mixture of the second solid and water as the cold fluid has an increased temperature after heat exchange in the heat exchange device, i.e., the heat exchange device achieves the effect of preheating. In order to improve production efficiency and reduce energy consumption, the above mixture can be further subjected to refining according to the process of steps S1 and S2, achieving continuous operation.

[0076] In an embodiment, the third solid is obtained by a solid-liquid separation method such as centrifugal filtration, plate-and-frame filtration, rotary drum filtration, etc.

[0077] In an embodiment, the third solid can be washed and dried.

[0078] The drying method includes, but is not limited to, any one or a combination of several of paddle drying, air flow drying, or belt drying.

[0079] In an embodiment, after step (3) is completed, the operation process and conditions of step (3) can be repeated one or more times.

[0080] The extraction method of the embodiment of the present application can improve the purity and quality of the long-chain dibasic acid product, the product has a large particle size, and the method is simple and easy to operate, which is beneficial to large-scale industrial production.

[0081] The extraction method of the embodiment of the present application has a higher quality index of the obtained product than the long-chain dibasic acid produced by a chemical method, which is more beneficial to improving the quality of downstream products.

[0082] The present application also provides a long-chain dibasic acid product, the purity of the long-chain dibasic acid product is > 98.5%, and / or the ash content is < 50 ppm, and / or the nitrogen content is < 30 ppm.

[0083] Further, the purity of the long-chain dibasic acid product is > 99%, and / or the ash content is < 35 ppm, and / or the nitrogen content is < 25 ppm. DETAILED DESCRIPTION

[0084] Hereinafter, the extraction and refining method of the long-chain dibasic acid of the present application will be described in detail in conjunction with specific examples. Unless otherwise specified, the raw materials used can be obtained commercially.

[0085] The test method of the iodine adsorption value of activated carbon is referred to GB / T 7702.7-2023 Coal Quality Granular Activated Carbon Test Methods Part 7: Determination of Iodine Adsorption Value. The unit of iodine adsorption value is mg / g.

[0086] Example 1-4 Fermentation production of different long-chain dibasic acids

[0087] The glycerol mycelium of Candida tropicalis CAT H1614 (preserved number CCTCC NO: M 2013143, which has been disclosed in Chinese patent CN110218661A) was inoculated into a seed bottle containing 30 ml of YPD liquid medium (glucose 2%, yeast extract 1%, peptone 2%), pH was natural, and the seed bottle was cultured at 29°C under 250 rpm shaking bed for 1 day.

[0088] The seed bottle seed is inoculated into a seed tank containing 5L seed culture medium (sucrose 2.2%, corn syrup 0.3%, yeast extract 0.5%, KH2PO4 0.8%, urea 0.3%), the inoculation amount is 10%, the initial pH of the system after inoculation is 6.0, the culture is carried out at 29°C, the ventilation amount is 0.4vvm, the tank pressure is 0.08MPa, the culture is carried out for 18h, and the pH naturally decreases to 3 during the culture process. The OD 620 When the OD reaches 0.7, it is inoculated into a fermentation tank containing 6L fermentation culture medium (glucose 4%, corn syrup 0.5%, yeast extract 0.4%, potassium nitrate 1%, potassium dihydrogen phosphate 0.1%, urea 0.12%, ammonium sulfate 0.06% and sodium chloride 0.1%), the initial volume after inoculation is 5L, the inoculation amount is 20%, the fermentation process is controlled at 30°C, the ventilation amount is about 0.4vvm, the tank pressure (gauge pressure) is 0.13MPa, and the dissolved oxygen is controlled not to be less than 20%. The pH of the fermentation broth is controlled by adding alkali. In the early stage of fermentation, the main process is the growth of the bacteria, the initial pH is 6.5, the pH of the fermentation broth gradually decreases with the growth of the microorganism, the pH is controlled not to be less than 3.0, when the optical density (OD 620 ) of the bacteria is greater than 0.5 (diluted 30 times), the pH is controlled to be 4.9-5.2 until the end of the fermentation. After 10-20h of fermentation, the substrate alkane is added in batches, and the alkane content in the fermentation broth is controlled to be not more than 10%.

[0089] Examples 1-4 are respectively: according to the above fermentation process, decane (example 1), dodecane (example 2), tridecane (example 3), and hexadecane (example 6) are fermented to prepare the corresponding long-chain dibasic acid.

[0090] Examples 5-8 are fermented to produce different long-chain dibasic acids

[0091] Referring to the fermentation methods of examples 4-9 in the Chinese patent with application number CN200410018255.7, different carbon atom number alkanes are used as fermentation substrates to ferment and produce different long-chain dibasic acids.

[0092] Examples 5-8 are respectively: decane (example 5), dodecane (example 6), tridecane (example 7), and hexadecane (example 8) are used as fermentation substrates to ferment and prepare the corresponding long-chain dibasic acid.

[0093] Table 1

[0094] Example 9-Extraction and purification of dodecanedioic acid

[0095] The dodecanedioic acid (DC12) fermentation broth obtained in Example 3 was used as the extraction raw material. The pH of the dodecanedioic acid fermentation broth was 5.0, and the dry weight of insoluble substances accounted for 19.4wt% of the fermentation broth. The details are as follows:

[0096] Step (1): The pH of the fermentation broth was adjusted to 7.9 using a 25wt% sodium hydroxide solution, and then the mixture was heated to obtain a mixture in which the dry weight of insoluble substances accounted for 1.4wt%;

[0097] Step (2): The same as in Example 10-A;

[0098] Step (3): The same as in Example 10-A.

[0099] Example 9-B Extraction and purification of dodecanedioic acid

[0100] The dodecanedioic acid (DC12) fermentation broth obtained in Example 3 was used as the extraction raw material. The pH of the dodecanedioic acid fermentation broth was 5.0, and the dry weight of insoluble substances accounted for 19.4wt% of the fermentation broth. The details are as follows:

[0101] Step (1): The pH of the fermentation broth was adjusted to 7.9 using a 25wt% sodium hydroxide solution, and then the mixture was heated to obtain a mixture in which the dry weight of insoluble substances accounted for 1.4wt%;

[0102] Step (2): The same as in Example 10-A;

[0103] Step (3): The same as in Example 10-A.

[0104] Example 10-A Extraction and purification of dodecanedioic acid

[0105] The dodecanedioic acid fermentation broth obtained in Example 7 was used as the extraction raw material. The pH of the dodecanedioic acid fermentation broth was 8.0, and the dry weight of insoluble substances accounted for 8.5wt% of the fermentation broth. The details are as follows:

[0106] (1) The fermentation broth was heated to obtain a mixture in which the dry weight of insoluble substances accounted for 1.5wt%;

[0107] (2) The mixture was filtered to obtain a filtrate, and the filtrate was subjected to acidification crystallization and solid-liquid separation treatment;

[0108] (3) Purification treatment.

[0109] In step (2):

[0110] The filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 microns is used in the membrane filtration, and the operating pressure is 0.5 MPa; when acidifying and crystallizing, sulfuric acid is used to adjust the pH value of the filtrate to 3.5; and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0111] In step (3):

[0112] The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 95wt%) according to a mass ratio of 1:2.2, 3.5% of the mass of the first solid of activated carbon (iodine adsorption value 900mg / g) is added for decolorization treatment, the temperature of the decolorization treatment is 85°C, the time of the decolorization treatment is 45 minutes, the decolorization liquid is cooled to 30°C for crystallization, a solid-liquid mixture is obtained, and the solid-liquid mixture is separated by plate and frame filtration to obtain a second solid, and the second solid is dried to obtain a dodecanedioic acid product.

[0113] Example 10-B Extraction and purification of dodecanedioic acid

[0114] The dodecanedioic acid fermentation broth obtained in Example 7 is used as the extraction raw material. The pH of the dodecanedioic acid fermentation broth is 8.0, and the dry weight of the insoluble substance accounts for 8.5wt% of the mass percentage of the fermentation broth. The specific process is as follows:

[0115] (1) Heating the fermentation broth to obtain a mixture liquid with a dry weight of insoluble substance of 1.4wt%;

[0116] (2) Filtering the mixture liquid to obtain a filtrate, and the filtrate is subjected to decolorization treatment, and the decolorization liquid is subjected to acidification crystallization and solid-liquid separation treatment;

[0117] (3) Purification treatment.

[0118] In step (2):

[0119] The filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 microns is used in the membrane filtration, and the operating pressure is 0.5 MPa;

[0120] Activated carbon (iodine adsorption value 750mg / g) is added to the filtrate obtained after filtration as a decolorizing agent, and the amount of activated carbon is 2% of the mass of dodecanedioic acid contained in the filtrate, and the decolorization is carried out at 80°C for 45 minutes;

[0121] When acidifying and crystallizing, sulfuric acid is used to adjust the pH value of the decolorization liquid to 3.6; and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0122] In step (3):

[0123] The first solid was mixed with an organic solvent acetic acid solution (acetic acid content 95wt%) at a mass ratio of 1:2.5, and 3% of activated carbon (iodine adsorption value 750mg / g) based on the mass of the first solid was added for decolorization treatment. The decolorization treatment temperature was 95°C, and the decolorization treatment time was 40 minutes. The decolorization liquid was cooled to 30°C for crystallization, to obtain a solid-liquid mixture. The solid-liquid mixture was separated by plate and frame filtration to obtain a second solid. The second solid was dried to obtain the dodecanedioic acid product.

[0124] Example 11 Extraction and purification of dodecanedioic acid

[0125] The process was substantially the same as in Example 10-A, except that:

[0126] Step (1): The mixture liquid obtained by heating the fermentation liquid had a dry weight of insoluble matter of 3.8wt%. The other steps were the same as in Example 10-A.

[0127] Step (2): The same as in Example 10-A.

[0128] Step (3): The activated carbon used had an iodine adsorption value of 300mg / g. The other steps were the same as in Example 10-A.

[0129] Example 12 Extraction and purification of dodecanedioic acid

[0130] Step (1): The same as in Example 10-A.

[0131] Step (2): The same as in Example 10-A.

[0132] Step (3): The first solid was mixed with an organic solvent acetic acid solution (acetic acid content 94wt%) at a mass ratio of 1:3, and 3% of activated carbon (iodine adsorption value 800mg / g) based on the mass of the first solid was added for decolorization treatment. The decolorization treatment temperature was 85°C, and the decolorization treatment time was 45 minutes. The decolorization liquid was cooled to 30°C for crystallization, to obtain a solid-liquid mixture. The solid-liquid mixture was separated by plate and frame filtration to obtain a second solid. The second solid was added to water at a solid to water mass ratio of 1:10, heated to 110°C, and maintained at 110°C for 80 minutes. The temperature was then lowered to 42°C, and the solid was filtered and dried to obtain the dodecanedioic acid product.

[0133] Example 13 Extraction and purification of decanedioic acid

[0134] The process was substantially the same as in Example 10-A, except that the dodecanedioic acid (DC10) fermentation liquid obtained in Example 1 was used as the extraction raw material. The pH of the decanedioic acid fermentation liquid was 5.1, and the dry weight of insoluble matter was 17.5wt% of the fermentation liquid.

[0135] (1) using 27wt% sodium hydroxide solution to adjust the pH value of the fermentation liquor to 8.0, and heating to obtain a mixed liquor with the dry weight of insoluble substances accounting for 1.7wt%;

[0136] (2) filtering the mixed liquor to obtain a filtrate, and performing acidification crystallization and solid-liquid separation treatment on the filtrate;

[0137] (3) refining treatment.

[0138] In step (2):

[0139] The filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 microns is used in the membrane filtration, and the operating pressure is 0.5 MPa; in the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.2; and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0140] In step (3):

[0141] The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 95wt%) according to a mass ratio of 1:3, 4% of the mass of the first solid of activated carbon (iodine adsorption value 1000mg / g) is added for decolorization treatment, the temperature of the decolorization treatment is 88℃, the time of the decolorization treatment is 50 minutes, the decolorization liquid is cooled to 30℃ for crystallization, a solid-liquid mixture is obtained, and the solid-liquid mixture is subjected to solid-liquid separation by plate and frame filtration to obtain a second solid, and the second solid is dried to obtain a decanoic acid product.

[0142] Example 14 Extraction and refining of hexadecanoic acid

[0143] The same as example 10-A, except that the hexadecanoic acid (DC16) fermentation liquor obtained in example 8 is used as the extraction raw material. The pH of the hexadecanoic acid fermentation liquor is 8.2, and the dry weight of insoluble substances accounts for 5.9wt% of the mass percentage of the fermentation liquor, as follows:

[0144] (1) heating the fermentation liquor to obtain a mixed liquor with the dry weight of insoluble substances accounting for 1.9wt%;

[0145] (2) filtering the mixed liquor to obtain a filtrate, and performing acidification crystallization and solid-liquid separation treatment on the filtrate;

[0146] (3) refining treatment.

[0147] In step (2):

[0148] The filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 microns is used in the membrane filtration, and the operating pressure is 0.5 MPa; in the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.2; and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0149] In step (3):

[0150] The first solid was mixed with an organic solvent acetic acid solution (acetic acid content 94 wt%) at a mass ratio of 1:3, and 3.5% of activated carbon (iodine adsorption value 650 mg / g) based on the mass of the first solid was added for decolorization treatment. The decolorization treatment was carried out at a temperature of 82°C for 55 minutes. The decolorized solution was cooled to 35°C for crystallization. A solid-liquid mixture was obtained, which was separated by plate and frame filtration to obtain a second solid. The second solid was added to water at a solid to water mass ratio of 1:5, and heated to 140°C. After being kept at 140°C for 50 minutes, the temperature was decreased to 38°C, and the solid was filtered and dried to obtain the dodecanedioic acid product.

[0151] Example 15 Extraction and purification of dodecanedioic acid

[0152] Step (1): same as Example 10-A;

[0153] Step (2): same as Example 10-A;

[0154] Step (3): the first solid was mixed with an organic solvent acetic acid solution (acetic acid content 84 wt%) at a mass ratio of 1:3.0, and 2.5% of activated carbon (iodine adsorption value 800 mg / g) based on the mass of the first solid was added for decolorization treatment. The decolorization treatment was carried out at a temperature of 83°C for 110 minutes. The decolorized solution was cooled to 33°C for crystallization. A solid-liquid mixture was obtained, which was separated by centrifuge to obtain a second solid. The second solid was mixed with water to suspend the second solid, and then heated to 103.5°C, and then cooled to 39°C. The mixture was then fed into a centrifuge for centrifugal separation. The obtained solid was dried to obtain the dodecanedioic acid product.

[0155] Example 16 Extraction and purification of dodecanedioic acid

[0156] Step (1): same as Example 10-A;

[0157] Step (2): same as Example 10-A;

[0158] Step (3): the first solid was mixed with an organic solvent acetic acid solution (acetic acid content 86 wt%) at a mass ratio of 1:3.5, and 2.8% of activated carbon (iodine adsorption value 800 mg / g) based on the mass of the first solid was added for decolorization treatment. The decolorization treatment was carried out at a temperature of 85°C for 90 minutes. The decolorized solution was cooled to 35°C for crystallization. A solid-liquid mixture was obtained, which was separated by centrifuge to obtain a second solid.

[0159] The second solid and water are mixed to suspend the second solid, the uniformly mixed solid-liquid mixture is continuously fed into a heat exchange device to be preheated, then fed into a heating device to be heated to 104.5°C, then fed back into the heat exchange device to exchange heat with the second solid and water mixture to be preheated (i.e. cold fluid), the temperature of the hot fluid is reduced to 41°C after heat exchange in the heat exchange device, then fed into a buffer tank or directly fed into a centrifuge without passing through the buffer tank to be centrifuged, the obtained solid is dried to obtain the dodecanedioic acid product.

[0160] Example 1 Extraction and purification of dodecanedioic acid

[0161] The same as Example 10-A, except that:

[0162] (1) The mixture liquid obtained by heating the fermentation liquid to obtain insoluble solids has a dry weight percentage of 5wt%;

[0163] Step (2) is the same as Example 10-A;

[0164] Step (3): The iodine adsorption value of the activated carbon is 150mg / g.

[0165] Step (4): Repeat the process of step (3) 1 time.

[0166] Table 2 Test data of long-chain dibasic acid product

[0167] Unless specifically limited, the terms used in the present application are intended to have the meanings commonly understood by those skilled in the art.

[0168] The embodiments described in the present application are for illustrative purposes only and are not intended to limit the scope of protection of the present application, and those skilled in the art can make various other replacements, changes and improvements within the scope of the present application, therefore, the present application is not limited to the above embodiments, but is limited only by the claims.

Claims

1. A method for extracting and purifying long-chain dibasic acid, characterized by, The method comprises the following steps: (1) heating the fermentation liquor of long-chain dibasic acid to reduce the content of insoluble substances in the fermentation liquor, to obtain a mixed liquor with a dry weight percentage of insoluble substances of less than or equal to 4 wt%; (2) filtering the mixed liquor to obtain a filtrate, and then performing acidification crystallization treatment and solid-liquid separation treatment on the filtrate with or without decolorization treatment to obtain a first solid; (3) refining the first solid.

2. The method of claim 1, wherein, In step (1), an alkali is added before, at the same time as, or after the heating treatment to adjust the pH value of the system to 6-11, further to 7.5-10, and further to 7.5-9.

3. The method of claim 1, wherein, The long-chain dibasic acid is selected from any one or a combination of two or more of decanoic acid, undecanoic acid, dodecanoic acid, tridecanoic acid, tetradecanoic acid, pentadecanoic acid, hexadecanoic acid, heptadecanoic acid, octadecanoic acid, and 9-alkenyl-octadecanoic acid.

4. The method of claim 1, wherein, In step (2), the filtration is membrane filtration. Further, the membrane is selected from a ceramic membrane; and / or, during membrane filtration, the operating pressure is 0.1-1.2 MPa, and the membrane pore size is 0.01-0.5 microns.

5. The method of claim 1, wherein, In step (2), the decolorization treatment uses activated carbon as a decolorizing agent, and the iodine adsorption value of the activated carbon is greater than or equal to 250 mg / g, further greater than or equal to 500 mg / g, and further 600-1500 mg / g. And / or, In step (2), the acidification crystallization treatment comprises adjusting the pH value of the filtrate or the decolorized liquid obtained by decolorization treatment on the filtrate to 2-4.

6. The method of claim 1, wherein, In step (3), the refining treatment comprises any one or a combination of two or more of recrystallization, melt crystallization, extraction, distillation, chromatographic separation, and water treatment.

7. The method of claim 1, wherein, The refining treatment in step (3) comprises the following steps: mixing the first solid with an organic solvent, performing decolorization treatment at 75-100°C, and then performing crystallization treatment and solid-liquid separation treatment on the decolorized liquid to obtain a second solid.

8. The method of claim 7, wherein, The organic solvent is selected from one or a combination of two or more of an organic acid, an alcohol, an ester, and an alkane; and / or, The concentration of the organic solvent is greater than or equal to 75%, further greater than or equal to 79%, further greater than or equal to 80.5%, further greater than or equal to 85%, further greater than or equal to 87.5%, further greater than or equal to 89.5%, further greater than or equal to 90%, further greater than or equal to 90.5%, further greater than or equal to 95%, further greater than or equal to 97%, and further greater than or equal to 99%.

9. The method according to claim 7 or 8, characterized in that, The organic solvent comprises any one or a combination of two or more of acetic acid, a C1-C4 acetic acid alcohol ester, and a C3-C8 alcohol, and is preferably any one or a combination of two or more of methyl acetate, ethyl acetate, n-propanol, isopropyl alcohol, and n-butanol.

10. The method of claim 7, wherein, The decolorization treatment uses activated carbon as a decolorizing agent, and the iodine adsorption value of the activated carbon is greater than or equal to 250 mg / g, further greater than or equal to 500 mg / g, and further 600-1500 mg / g; and / or, The amount of decolorizing agent is 0.1%-10% of the first solid, further 0.5%-5%, further 1%-5%, and further 1.2%-4.8%.

11. The method of claim 7, wherein, The refining treatment in step (3) further comprises washing the second solid.

12. The method of claim 7 or 11, wherein, The refining treatment of step (3) further comprises the following steps: mixing the second solid with water, heating to 70-150°C, cooling to 20-65°C after no holding or holding for 15-150 minutes, and then performing solid-liquid separation treatment to obtain a third solid.

13. The method of claim 7 or 12, wherein, The refining treatment of step (3) further comprises the following steps: S1: mixing the second solid with water, and heating the mixed material to 90-135°C, S2: cooling to 20-65°C, and then obtaining a third solid through solid-liquid separation treatment.

14. The method of claim 13, wherein: In step S1, the solid I and water are mixed, and the mixed material is heated to 92-130°C, 100-110°C, or 100-120°C.

15. The method of claim 1, wherein, The pH value of the fermentation liquor is 2-12.

16. The method of claim 2, wherein, The base includes sodium hydroxide, potassium hydroxide, ammonia water, liquid ammonia, or a mixed base containing at least two of them. Preferably, the base exists in the form of an aqueous solution, and the concentration is 10wt%-40wt%, further 15wt%-35wt%, and further 15wt%-30wt%.

17. The long-chain dibasic acid product produced according to the process of any one of claims 1 to 16, characterized by, The purity of the long-chain dibasic acid product is >98.5%, and / or, the ash content is <50ppm, and / or, the nitrogen content is <30ppm; Preferably, the purity is >99%, and / or, the ash content is <35ppm, and / or, the nitrogen content is <25ppm.

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