Extracting and refining method of long-chain dicarboxylic acid and product

Abstract

The invention provides a method for extracting and refining long-chain dicarboxylic acid and a product, and the method comprises the following steps: (1) carrying out heating treatment on fermentation liquor of long-chain dicarboxylic acid to reduce the content of insoluble substances in the fermentation liquor so as to obtain mixed feed liquor in which the dry weight ratio of the insoluble substances is less than 4wt%; (2) filtering the mixed material liquid to obtain filtrate, carrying out acidification crystallization treatment and solid-liquid separation treatment on the filtrate through or without decoloration treatment to obtain a first solid; and (3) refining the first solid. The extraction and refining method provided by the invention can improve the purity and quality of the long-chain dicarboxylic acid product, and the product has large particle size, is simple and easy to operate, and is beneficial to large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the extraction and purification of long-chain dibasic acid, in particular to a method for extracting and purifying long-chain dibasic acid from long-chain dibasic acid fermentation liquid produced by microbial fermentation. Background Art

[0002] Long-chain dibasic acids refer to aliphatic dicarboxylic acids with more than 10 carbon atoms in the carbon chain (abbreviated as DCn, n≥10). They are a type of fine chemical products with important and extensive industrial uses. They are important raw materials for synthesizing high-grade fragrances, high-performance engineering plastics, high-temperature dielectrics, high-grade hot melt adhesives, cold-resistant plasticizers, high-grade lubricants, high-grade paints and coatings in the chemical industry. The production methods of long-chain dibasic acids include chemical synthesis and biological fermentation.

[0003] The production of long-chain dibasic acids by biological fermentation is an application of microbial fermentation technology in the field of petrochemicals that emerged in the 1970s. It generally uses petroleum byproduct wax oil as raw material, and has the advantages of a wide source of raw materials, simple production process, and mild production conditions. The crude long-chain dibasic acid prepared by biological methods usually contains dibasic acids, monobasic acids, hydroxy acids and other miscellaneous acids of other carbon chain lengths that are not the main products, as well as impurities such as pigments, inorganic salts, and nitrogen-containing compounds. If the impurity content in the product is high, it is easy to affect the performance of polyamide when copolymerized with other monomers, such as when polymerized with diamines to prepare polyamide. Therefore, it is necessary to find a simple and efficient extraction and purification technology for long-chain dibasic acids. Summary of the invention

[0004] A main purpose of the present invention is to provide a method for extracting and refining long-chain dibasic acids, the method comprising the following steps:

[0005] (1) heating the fermentation broth of the long-chain dibasic acid to reduce the content of insoluble matter in the fermentation broth to obtain a mixed liquid in which the dry weight ratio of the insoluble matter is less than 4 wt %;

[0006] (2) filtering the mixed liquid to obtain a filtrate, and subjecting the filtrate to an acidification crystallization treatment and a solid-liquid separation treatment with or without a decolorization treatment to obtain a first solid;

[0007] (3) The first solid is subjected to a purification treatment.

[0008] The long-chain dibasic acid is selected from any one of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedicarboxylic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedicarboxylic acid, and 9-ene-octadecanedicarboxylic acid, or a combination of two or more thereof.

[0009] The fermentation broth of the long-chain dibasic acid can be a fermentation broth obtained by a method of using alkanes, fatty acids and their derivatives as fermentation substrates and using microorganisms to ferment and produce long-chain dibasic acids; wherein the microorganisms can convert the terminal methyl groups of alkanes, fatty acids and fatty acid derivatives into carboxyl groups by oxidation, thereby generating long-chain dibasic acids. The long-chain dibasic acid in the fermentation broth exists in the form of long-chain dibasic acids and / or long-chain dibasic acid salts.

[0010] In the present application, the specific method for preparing the fermentation broth of the long-chain dibasic acid is not particularly limited.

[0011] In some preferred embodiments, the fermentation broth of long-chain dibasic acid is obtained by culturing bacteria that produce long-chain dibasic acid, controlling the pH of the fermentation system to be above 2.0 during the growth phase of the bacteria and the pH of the fermentation system to be 2-12 during the conversion phase.

[0012] In some preferred embodiments, the fermentation substrate is alkane, the fermentation temperature is 28-32° C., the air volume is 0.3-1.0 vvm, the pressure is 0.05-0.14 MPa, and the inoculation amount is 10-30% (v / v).

[0013] In some preferred embodiments, the long-chain dibasic acid-producing microorganism comprises Candida viswanathii, Candida tropicalis or Candida sake.

[0014] In one embodiment, the pH value 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 may be 4.2, 5.0, 5.7, 6.5, 7.2, 8.0, or 8.3.

[0015] In step (1), the pH value of the fermentation broth may be the natural pH value of the fermentation broth obtained after terminating the fermentation, or may be the pH value adjusted by adding acid and / or alkali.

[0016] In one embodiment, the pH value of the fermentation broth is adjusted to 2 to 12 by adding acid and / or base. The base includes sodium hydroxide, potassium hydroxide, ammonia water, liquid ammonia, ammonia gas, or a mixed base containing at least two of them. The base exists in the form of an aqueous solution with a concentration of 10wt% to 40wt%, further 15wt% to 35wt%, and further 15wt% to 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 them.

[0017] In some embodiments, the pH value of the fermentation broth of the long-chain dibasic acid is adjusted to obtain a fermentation broth having a pH value within the range described in step (1).

[0018] It is generally known to those skilled in the art that the concentration of the fermentation liquid containing the long-chain dibasic acid after the fermentation is completed is generally 5 wt% to 20 wt%. The long-chain dibasic acid exists in the form of a long-chain dibasic acid and / or a long-chain dibasic acid salt.

[0019] In the present application, the heating temperature in step (1) is not particularly limited, as long as the fermentation liquid can be heated to obtain a mixed liquid in which the dry weight ratio of insoluble matter is within the range specified in the present application.

[0020] It is generally known to those skilled in the art that the insoluble matter in the fermentation broth of the long-chain dibasic acid after the fermentation is completed includes: undissolved long-chain dibasic acid, insoluble protein, pigment, bacteria, inorganic salts, miscellaneous acids, etc.

[0021] In one embodiment, in step (1), the dry weight percentage of insoluble matter in the fermentation broth of the long-chain dibasic acid is 2wt% to 20wt%, further 2.5wt% to 20wt%, further 3wt% to 20wt%, further 3.5wt% to 20wt%, further 4.5wt% to 20wt%. The dry weight percentage of insoluble matter in the fermentation broth is calculated as follows: dry weight of insoluble matter in the fermentation broth (g) / total mass of the fermentation broth (g)*100%. The insoluble matter in the fermentation broth can be separated by centrifugation or filtration.

[0022] In this application, the insoluble content of the fermented liquid is reduced by heating it. The heat treatment changes the composition of the fermented liquid, the degree of suspension and the aggregation state of the long-chain dibasic acid in the fermented liquid. The heating denatures some impurities in the fermented liquid, dissolves and precipitates some impurities, and the heating also promotes the dissolution of the long-chain dibasic acid. The present application found that after the heat treatment, the fermented liquid with the above-mentioned insoluble content characteristics was separated by filtration, and the impurity content in the obtained filtrate was significantly reduced, which is beneficial to the improvement of product purity.

[0023] In one embodiment, the dry weight percentage of insoluble matter in the mixed liquid 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.

[0024] The calculation method of the dry weight ratio of insoluble matter in the mixed liquid is as follows: dry weight of insoluble matter in the mixed liquid (g) / total mass of the mixed liquid (g)*100%. The insoluble matter in the mixed liquid can be separated by centrifugation or filtration.

[0025] In some embodiments, in step (2), the mixed liquid is filtered, and the filtrate or the decolorized liquid obtained after the filtrate is decolorized is subjected to acidification crystallization and solid-liquid separation to obtain a first solid. The first solid mainly contains long-chain dibasic acids, which have stable quality and high purity, and can already meet some market demands.

[0026] In step (2) of one embodiment, the filtration method is preferably membrane filtration.

[0027] In step (2) of one embodiment, the membrane used in the membrane filtration treatment is a ceramic membrane.

[0028] In step (2) of one embodiment, during membrane filtration, the operating pressure 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.

[0029] In step (2) of one embodiment, the pore size of the filtration membrane is 0.01 to 0.5 micrometers, further 0.01 to 0.2 micrometers, further 0.03 to 0.15 micrometers, further 0.05 to 0.1 micrometers.

[0030] In step (2) of one embodiment, the filtrate is decolorized to obtain a decolorized solution, and the decolorized solution is subjected to an acidification and crystallization treatment.

[0031] It is conventionally known to those skilled in the art that the decolorization treatment includes the steps of adding a decolorizing agent to the filtrate, and separating (e.g., centrifuging or filtering) the decolorizing agent to obtain a decolorized solution. Preferably, activated carbon is used as the decolorizing agent, and the iodine value of the activated carbon is 400 or more, further 550 or more, and further 600 to 1500.

[0032] In one embodiment, the amount of the decolorizing agent added during the decolorization process is 0.5% to 10% of the mass of the long-chain dibasic acid contained in the decolorized liquid (or filtrate), further 1% to 5%, further 1.2% to 4.8%.

[0033] In one embodiment, the temperature of the decolorization treatment is 50-100°C, and may further be 60-90°C, for example, 65°C, 70°C, 75°C, 80°C, 85°C, 90°C, or 95°C.

[0034] In one embodiment, the decolorization treatment time is 10 to 180 minutes, further can be 15 to 120 minutes, further can be 18 to 100 minutes, for example 20 minutes, 25 minutes, 30 minutes, 40 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, 150 minutes.

[0035] In one embodiment, after decolorization is completed, the decolorizing agent is preferably separated by plate and frame filtration, chamber filtration, centrifugal filtration, membrane filtration, etc. to obtain a decolorized solution.

[0036] 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 filtrate is decolorized to 2-4, heating it to 80-130° C., keeping it warm for 10-120 minutes, and then cooling it to 25-40° C.

[0037] 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 filtrate is decolorized to 2.2-3.8, for example, 2, 2.2, 2.5, 2.6, 2.8, 3, 3.2, 3.5, 3.8, and heating to 80-130° C., keeping warm for 10-120 min, and then cooling to 25-40° C.

[0038] In step (2) of one embodiment, during the acidification crystallization process, the temperature is raised to 85-120°C, further to 85-110°C, further to 90-110°C, further to 92-97°C, and then lowered to 25-40°C.

[0039] In step (2) of one embodiment, during the acidification crystallization process, the holding time is 20 to 100 minutes, and further 30 to 90 minutes.

[0040] In step (2) of one embodiment, during the acidification crystallization process, the cooling temperature is 25 to 40° C., further 32 to 38° C., to precipitate crystals.

[0041] 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.

[0042] In step (2) of one embodiment, solid-liquid separation is performed after the acidification crystallization treatment. The solid-liquid separation method may include filtration separation and centrifugal separation, such as plate and frame filtration, chamber filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0043] In step (2) of one embodiment, the first solid obtained after the solid-liquid separation treatment is washed and dried, and then subjected to the purification treatment of step (3).

[0044] In one embodiment, in step (3), the first solid obtained in step (2) is subjected to a refining treatment to obtain a long-chain dibasic acid product with improved quality.

[0045] In one embodiment, the refining treatment in step (3) comprises any one or a combination of two or more of recrystallization, melt crystallization, extraction, distillation, chromatography, and water treatment.

[0046] In step (3) of one embodiment, the refining treatment comprises the following steps:

[0047] The first solid is mixed with an organic solvent, and decolorized at 75° C. to 100° C. The decolorized liquid is crystallized and solid-liquid separated to obtain a second solid.

[0048] In one embodiment, the organic solvent may be one or more of an organic acid, alcohol, ester, and alkane that does not react with the long-chain dibasic acid. Here, "does not react with the long-chain dibasic acid" means that during the heating and heat preservation process of the refining treatment, the weight of the long-chain dibasic acid that reacts with the organic solvent accounts for ≤1% of the total weight of the long-chain dibasic acid.

[0049] In one embodiment, the organic solvent is selected from one or a combination of two or more of organic acids, alcohols, esters, and alkanes.

[0050] In one embodiment, the organic solvent may be any one of acetic acid, (C1-C4) alcohol acetate, C3-C8 alcohol, or a combination of two or more thereof, such as methyl acetate, ethyl acetate, n-propanol, isopropanol, n-butanol, etc. Acetic acid is preferred.

[0051] In one embodiment, the organic solvent contains water, such as an acetic acid solution.

[0052] In one embodiment, the concentration of the organic solvent is ≥90%, further ≥95%, further ≥97%, and further ≥99%.

[0053] In one embodiment, the mass ratio of the first solid to the organic solvent is 1:(1-10), further 1:(1-5).

[0054] In one embodiment, in the decolorization treatment, activated carbon is used as a decolorizing agent, and the iodine value of the activated carbon is 400 or more, further 550 or more, and further 600-1500.

[0055] The amount of the decolorizing agent may be 0.1% to 10% by weight of the first solid, preferably 1% to 5% by weight, and preferably 1.2% to 4.7% by weight.

[0056] In one embodiment, the temperature of the bleaching treatment can be 77°C to 100°C, further 77°C to 98°C, further 80°C to 98°C, for example 65°C, 70°C, 72°C, 75°C, 77°C, 80°C, 85°C, 90°C, 95°C.

[0057] In one embodiment, the decolorization treatment time can be 10 to 180 minutes, and further can be 15 to 120 minutes, for example, 20 minutes, 25 minutes, 30 minutes, 40 minutes, 45 minutes, 50 minutes, 60 minutes, 80 minutes, 100 minutes, or 150 minutes.

[0058] After decolorization is completed, the decolorizing agent can be separated by plate and frame filtration, centrifugal filtration, vacuum negative pressure filtration, etc.

[0059] In one embodiment, the crystallization treatment is a cooling crystallization treatment, and the terminal temperature of the cooling crystallization can be 20 to 40° C. The long-chain dibasic acid crystals are precipitated by the crystallization treatment.

[0060] In one embodiment, the cooling crystallization process is as follows:

[0061] First, cool down to T1℃ (the first cooling process), keep at T1℃ for 20 to 180 minutes, and then cool down to the end temperature (the second cooling process).

[0062] In one embodiment, the T1°C is 45 to 84°C, further 45 to 79°C, further 45 to 77°C, further 60 to 75°C.

[0063] In one embodiment, the holding time at T1° C. is 30 to 120 min.

[0064] In one embodiment, the average cooling rate of the first cooling process is less than the average cooling rate of the second cooling process.

[0065] The average cooling rate of the first cooling process can be 0.5-12°C / h, further can be 0.5-10°C / h, further can be 1-7°C / h, further can be 2-6°C / h, for example 10°C / h, 8°C / h, 5°C / h.

[0066] The average cooling rate of the second cooling process can be 5-15°C / h, further can be 8-15°C / h, further can be 12°C / h, 10°C / h, 7°C / h.

[0067] In one embodiment, the solid-liquid separation treatment includes plate and frame filtration, chamber filtration, centrifugal filtration, vacuum negative pressure filtration and the like.

[0068] In one embodiment, after the solid-liquid separation treatment, the second solid is obtained, which is a long-chain dibasic acid product with high purity, stable quality and wide application fields.

[0069] In one embodiment, the purification treatment in step (3) further comprises: washing and / or drying the second solid.

[0070] In one embodiment, the refining treatment in step (3) further comprises: placing the second solid in water at 70 to 150° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation to obtain a third solid.

[0071] Furthermore, the mass ratio of the second solid to water may be 1:(2-20), further may be 1:(3-15), further may be 1:(3-10).

[0072] Furthermore, the refining treatment in step (3) further comprises: placing the second solid in water at 90 to 150° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation to obtain a third solid.

[0073] Furthermore, the refining treatment in step (3) further comprises: placing the second solid in water at 70 to 100° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation to obtain a third solid.

[0074] In one embodiment, the third solid is obtained by solid-liquid separation through centrifugal filtration, plate and frame filtration, drum filtration, etc.

[0075] In one embodiment, the purification treatment in step (3) further comprises: washing and drying the third solid.

[0076] The drying method includes but is not limited to any one or a combination of paddle drying, airflow drying or belt drying.

[0077] In one embodiment, after completing step (3), the operation process and conditions of step (3) may be repeated one or more times.

[0078] The extraction method of one embodiment of the present invention can improve the purity and quality of the long-chain dibasic acid product, the product has a large particle size, and is simple and easy to operate, which is conducive to large-scale industrial production.

[0079] The extraction method of one embodiment of the present invention has a higher quality index of the obtained product than the long-chain dibasic acid produced by chemical method, which is more conducive to improving the quality of downstream products.

[0080] The present invention also provides a long-chain dibasic acid product, the purity of the long-chain dibasic acid product is greater than 98.5%, and / or the ash content is less than 50ppm, and / or the iron ion content is less than 3ppm, and / or the nitrogen content is less than 30ppm, and / or the light transmittance at 440nm is greater than 97%,

[0081] Furthermore, the purity of the long-chain dibasic acid product is >99%, and / or the ash content is <35ppm, and / or the iron ion content is <2ppm, and / or the nitrogen content is <25ppm, and / or the transmittance at 440nm is >98%. DETAILED DESCRIPTION

[0082] The following is a detailed description of the extraction and purification method of the long-chain dibasic acid of the present invention in conjunction with specific examples. 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.

[0083] 1. Purity: detected by gas chromatography.

[0084] 2. 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 loss and calculate the percentage of the sample weight.

[0085] 3. Nitrogen content determination: measured by Kjeldahl method.

[0086] 4. Determination of iron ion content: The phenanthroline method is used for determination, and the content of iron salt is measured as Fe.

[0087] 5. Transmittance: Take a 25% dimethyl sulfoxide solution of the sample to be tested and use a spectrophotometer to detect its transmittance at 440nm.

[0088] 6. Screening rate: Screening rate = sample mass passing through the sieve / total sample mass before screening * 100%.

[0089] Examples 1 to 4 Fermentation production of different long-chain dibasic acids

[0090] A glycerol tube of Candida tropicalis CAT H1614 (deposit number: CCTCCNO: M2013143, disclosed in Chinese patent CN110218661A) was inoculated into a seed bottle containing 30 ml of YPD liquid medium (2% glucose, 1% yeast extract, 2% peptone), pH was natural, and cultured in a shaking incubator at 250 rpm at 29° C. for 1 day.

[0091] The seeds from the shake flask were inoculated into a seed tank containing 5 L of seed culture medium (2.2% sucrose, 0.3% corn syrup, 0.5% yeast extract, 0.8% KH2PO4, and 0.3% urea). The inoculation amount was 10%. The initial pH value of the inoculated system was 6.0. The culture was carried out at 29°C, with a ventilation rate of 0.4 vvm and a tank pressure of 0.08 MPa for 18 h. During the culture process, the pH naturally dropped to 3, and the OD 620When the pH reaches 0.7, inoculate it into a fermentation tank containing 6L fermentation medium (4% glucose, 0.5% corn syrup, 0.4% yeast extract, 1% potassium nitrate, 0.1% potassium dihydrogen phosphate, 0.12% urea, 0.06% ammonium sulfate and 0.1% sodium chloride). The initial volume after inoculation is 5L, the inoculation amount is 20%, the temperature during the fermentation process is controlled at 30°C, the ventilation volume is about 0.4vvm, the tank pressure (gauge pressure) is 0.13MPa, and the dissolved oxygen is controlled to be not less than 20%. The pH value of the fermentation liquid is controlled by adding alkali. The early stage of fermentation is mainly based on bacterial growth. The initial pH of the fermentation is 6.5. As the microorganisms grow, the pH of the fermentation liquid gradually decreases, and the pH is controlled to be not less than 3.0. When the optical density of the bacteria (OD 620 ) is greater than 0.5 (diluted 30 times), the pH is controlled at 4.9-5.2 until the end of fermentation. After 10-20 hours of fermentation, the substrate alkane is added in batches to control the alkane content in the fermentation liquid not to exceed 10%.

[0092] Examples 1 to 4 are respectively: according to the above fermentation process, decaalkane (Example 1), dodecaalkane (Example 2), tridecaalkane (Example 3), and hexadecane (Example 6) are fermented to obtain the corresponding long-chain dibasic acids.

[0093] Examples 5-8 Fermentation production of different long-chain dibasic acids

[0094] Referring to the fermentation method of Examples 4 to 9 in the Chinese patent application number CN200410018255.7, alkanes with different carbon numbers are used as fermentation substrates to produce different long-chain dibasic acids.

[0095] Examples 5 to 8 are respectively: using decaalkane (Example 5), dodecaalkane (Example 6), tridecaalkane (Example 7), and hexadecane (Example 8) as fermentation substrates to produce the corresponding long-chain dibasic acids.

[0096] Table 1

[0097] Fermentation substrate Fermented products The pH of the fermentation broth obtained Example 1 C10 Alkanes DC10 5.1 Example 2 C11 Alkanes DC11 5.0 Example 3 C12 Alkanes DC12 5.0 Example 4 C16 Alkanes DC16 5.2 Example 5 C10 Alkanes DC10 8.0 Example 6 C11 Alkanes DC11 8.1 Example 7 C12 Alkanes DC12 8.0 Implementation Benefits 8 C16 Alkanes DC16 8.2

[0098] Example 9 Extraction and purification of dodecanedioic acid

[0099] The fermentation broth of dodecanedioic acid (DC12) obtained in Example 3 was used as the extraction raw material. The pH of the fermentation broth of dodecanedioic acid was 5.0, and the dry weight of insoluble matter accounted for 19.4 wt % of the fermentation broth. The details are as follows:

[0100] Step (1): adjusting the pH value of the fermentation liquid to 7.9 using a 25 wt % sodium hydroxide solution, and then heating to obtain a mixed liquid having a dry weight percentage of insoluble matter of 1.4 wt %;

[0101] Step (2): Same as Example 10.

[0102] Step (3): Same as Example 10.

[0103] Example 10 Extraction and purification of dodecanedioic acid

[0104] 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 matter accounted for 8.5 wt % of the fermentation broth. The details are as follows:

[0105] (1) heating the fermentation liquid to obtain a mixed liquid in which the dry weight of insoluble matter accounts for 1.5 wt %;

[0106] (2) filtering the mixed liquid to obtain a filtrate, decolorizing the filtrate, and subjecting the decolorized liquid to acidification, crystallization, and solid-liquid separation;

[0107] (3) Refining treatment.

[0108] In step (2):

[0109] a) the filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 micrometer is used for the membrane filtration, and the operating pressure is 0.5 MPa; activated carbon (iodine value is 850) is added to the filtrate obtained after filtration as a decolorizing agent, and the amount of activated carbon is 2% of the mass of the dodecanedioic acid contained in the filtrate, and the decolorization is carried out at 78° C. for 50 minutes;

[0110] b) subjecting the decolorized liquid to acidification crystallization and solid-liquid separation; 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 105° C. and kept for 40 minutes, and then the temperature is lowered to 35° C. to precipitate crystals, 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%) in a mass ratio of 1:2.2, and activated carbon (iodine value 1000) of 4% by mass of the first solid is added for decolorization. The decolorization temperature is 85°C and the decolorization time is 45 minutes. The decolorized liquid is cooled to 30°C for crystallization to obtain a solid-liquid mixture, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is dried to obtain a dodecanedioic acid product.

[0113] The process of cooling the decolorizing solution to 30°C is as follows: cooling from 85°C to 72°C, keeping at 72°C for 1 hour and then cooling to 30°C. 85°C to 72°C: the average cooling rate is 4°C / h, 72°C to 30°C: the average cooling rate is 8°C / h.

[0114] Example 11 Extraction of dodecanedioic acid

[0115] The method is basically the same as Example 10, except that: in step (1), a mixed liquid having an insoluble matter dry weight ratio of 3.8 wt% is obtained by heating; and in step (3), acetic acid decolorization is performed: the iodine value of the activated carbon is 400. The details are as follows:

[0116] Step (1): heating the fermentation liquid to obtain a mixed liquid having an insoluble matter dry weight percentage of 3.8 wt %;

[0117] Step (2): the same as in Example 10;

[0118] Step (3): the first solid is mixed with an organic solvent acetic acid solution (acetic acid content 95wt%) in a mass ratio of 1:2.2, and activated carbon (iodine value 400) of 4% by mass of the first solid is added for decolorization. The decolorization temperature is 85°C and the decolorization time is 45 minutes. The decolorized liquid is cooled to 30°C for crystallization to obtain a solid-liquid mixture, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is dried to obtain a dodecanedioic acid product.

[0119] The process of cooling the decolorizing solution to 30°C is as follows: cooling from 85°C to 72°C, keeping at 72°C for 1 hour and then cooling to 30°C. 85°C to 72°C: the average cooling rate is 4°C / h, 72°C to 30°C: the average cooling rate is 8°C / h.

[0120] Example 12 Extraction of dodecanedioic acid

[0121] Step (1): the same as in Example 10;

[0122] Step (2): the same as in Example 10;

[0123] Step (3): the first solid is mixed with an organic solvent acetic acid solution (acetic acid content 95wt%) in a mass ratio of 1:2.2, and activated carbon (iodine value 1200) of 4% by mass of the first solid is added for decolorization. The decolorization temperature is 85°C and the decolorization time is 45 minutes. The decolorized liquid is cooled to 30°C for crystallization to obtain a solid-liquid mixture, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is dried to obtain a dodecanedioic acid product.

[0124] The process of cooling the decolorizing solution to 30°C is as follows: cooling from 85°C to 72°C, keeping at 72°C for 1 hour and then cooling to 30°C. 85°C to 72°C: the average cooling rate is 4°C / h, 72°C to 30°C: the average cooling rate is 8°C / h.

[0125] Example 13 Extraction of dodecanedioic acid

[0126] Step (1): the same as in Example 10;

[0127] Step (2): the same as in Example 10;

[0128] In step (3):

[0129] The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 95wt%) in a mass ratio of 1:2.2, and activated carbon (iodine value 1000) of 4% by mass of the first solid is added for decolorization. The decolorization temperature is 85°C and the decolorization time is 45 minutes. The decolorized liquid is cooled to 30°C for crystallization to obtain a solid-liquid mixture, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is dried to obtain a dodecanedioic acid product.

[0130] The process of cooling the decolorizing solution to 30°C is as follows: cooling from 85°C to 72°C, keeping at 72°C for 1 hour and then cooling to 30°C. 85°C to 72°C: the average cooling rate is 15°C / h, 72°C to 30°C: the average cooling rate is 7°C / h.

[0131] Example 14 Extraction of dodecanedioic acid

[0132] Step (1): the same as in Example 10;

[0133] Step (2): the same as in Example 10;

[0134] Step (3): The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 94wt%) in a mass ratio of 1:3, and activated carbon (iodine value 750) of 4% of the mass of the first solid is added for decolorization. The decolorization temperature is 85°C and the decolorization time is 50 minutes. The decolorized liquid is cooled to 30°C for crystallization to obtain a solid-liquid mixture, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is added to water in a mass ratio of solid to water of 1:10, and after being kept at 120°C for 65 minutes, the temperature is cooled to 42°C, filtered, and a solid is obtained. The solid is dried to obtain a dodecanedioic acid product.

[0135] The process of cooling the decolorizing solution to 30°C is as follows: cooling from 85°C to 72°C, keeping at 72°C for 1 hour and then cooling to 30°C. 85°C to 72°C: the average cooling rate is 3°C / h, 72°C to 30°C: the average cooling rate is 9°C / h.

[0136] Example 15 Extraction of Decadianoic Acid

[0137] The method is basically the same as Example 10, except that the fermentation broth of deca-dicarboxylic acid (DC10) obtained in Example 1 is used as the extraction raw material. The pH of the fermentation broth of deca-dicarboxylic acid is 5.1, and the dry weight of insoluble matter accounts for 17.5 wt % of the fermentation broth. The details are as follows:

[0138] (1) adjusting the pH value of the fermentation liquid to 8.0 using a 27 wt % sodium hydroxide solution, and heating to obtain a mixed liquid having a dry weight percentage of insoluble matter of 1.5 wt %;

[0139] (2) filtering the mixed liquid to obtain a filtrate, decolorizing the filtrate, and subjecting the decolorized liquid to acidification, crystallization, and solid-liquid separation;

[0140] (3) Refining treatment.

[0141] In step (2):

[0142] a) the filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 microns is used for the membrane filtration, and the operating pressure is 0.5 MPa; activated carbon (iodine value is 900) is added to the filtrate obtained after filtration as a decolorizing agent, and the amount of activated carbon used is 2% of the mass of the deca-dicarboxylic acid contained in the filtrate, and the decolorization is carried out at 85° C. for 40 minutes;

[0143] b) subjecting the decolorized liquid to acidification crystallization and solid-liquid separation; wherein, during the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.2, the temperature is raised to 105° C. and kept for 60 minutes, and then the temperature is lowered to 30° C. to precipitate crystals, and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0144] In step (3):

[0145] The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 93wt%) in a mass ratio of 1:3, and activated carbon (iodine value 800) of 2.5% by mass of the first solid is added for decolorization. The decolorization temperature is 88°C and the decolorization time is 50 minutes. The decolorized liquid is cooled to 30°C for crystallization to obtain a solid-liquid mixture. The solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is dried to obtain a decacarbon dibasic acid product.

[0146] The process of cooling the decolorizing solution to 30°C is as follows: cooling from 88°C to 72°C, keeping at 72°C for 1 hour and then cooling to 30°C. 85°C to 72°C: the average cooling rate is 3°C / h, 72°C to 30°C: the average cooling rate is 10°C / h.

[0147] Example 16 Extraction of Undecanedicarboxylic Acid

[0148] The method is basically the same as Example 10, except that the fermentation liquid of undecane dicarboxylic acid (DC11) obtained in Example 6 is used as the extraction raw material. The pH of the fermentation liquid of undecane dicarboxylic acid is 8.1, and the dry weight of insoluble matter accounts for 3.1 wt% of the fermentation liquid. The details are as follows:

[0149] (1) heating the fermentation liquid to obtain a mixed liquid having an insoluble matter dry weight ratio of 1.3 wt %;

[0150] (2) filtering the mixed liquid to obtain a filtrate, and subjecting the filtrate to acidification, crystallization, and solid-liquid separation treatments;

[0151] (3) Refining treatment.

[0152] In step (2):

[0153] a) the filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 micrometers is used for membrane filtration, and an operating pressure of 0.4 MPa is used to obtain a filtrate;

[0154] b) subjecting the filtrate obtained in step a) to acidification crystallization treatment and solid-liquid separation treatment; wherein, during acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.5, the temperature is raised to 105° C. and kept warm for 40 minutes, then the temperature is lowered to 35° C. to precipitate crystals, and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0155] In step (3):

[0156] The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 92wt%) in a mass ratio of 1:3, and activated carbon (iodine value 1200) of 5% of the mass of the first solid is added for decolorization. The decolorization temperature is 85°C and the decolorization time is 45 minutes. The decolorized liquid is cooled to 32°C for crystallization to obtain a solid-liquid mixture, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is added to water in a mass ratio of solid to water of 1:8, and after being kept at 98°C for 65 minutes, the temperature is cooled to 45°C, filtered, and a solid is obtained, and the solid is dried to obtain an 11-carbon dibasic acid product.

[0157] The process of cooling the decolorizing solution to 32°C is as follows: from 85°C to 72°C, keep at 72°C for 2h, and then cool to 32°C. 85°C to 72°C: the average cooling rate is 5°C / h, 72°C to 32°C: the average cooling rate is 12°C / h.

[0158] Example 17 Extraction of Hexadecanedicarboxylic Acid

[0159] The method is basically the same as Example 10, except that the fermentation liquid of hexadecanedioic acid (DC16) obtained in Example 8 is used as the extraction raw material. The pH of the fermentation liquid of hexadecanedioic acid is 8.2, and the dry weight of insoluble matter accounts for 5.9 wt% of the fermentation liquid, as follows:

[0160] (1) heating the fermentation liquid to obtain a mixed liquid having an insoluble matter dry weight ratio of 1.9 wt %;

[0161] (2) filtering the mixed liquid to obtain a filtrate, decolorizing the filtrate, and subjecting the decolorized liquid to acidification, crystallization, and solid-liquid separation;

[0162] (3) Refining treatment.

[0163] In step (2):

[0164] a) the filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 microns is used for membrane filtration, and the operating pressure is 0.5 MPa; activated carbon (iodine value is 800) is added to the filtrate obtained after filtration as a decolorizing agent, the amount of activated carbon used is 2% of the mass of hexadecanedioic acid contained in the filtrate, and the decolorization is carried out at 85° C. for 40 minutes;

[0165] b) subjecting the decolorized liquid to acidification crystallization and solid-liquid separation; wherein, during the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.2, the temperature is raised to 105° C. and kept for 60 minutes, and then the temperature is lowered to 30° C. to precipitate crystals, and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0166] In step (3):

[0167] The first solid is mixed with an organic solvent acetic acid solution (acetic acid content 93wt%) in a mass ratio of 1:3, and activated carbon (iodine value 750) of 1.5% of the mass of the first solid is added for decolorization, the decolorization temperature is 82°C, the decolorization time is 50 minutes, the decolorized liquid is cooled to 35°C for crystallization, a solid-liquid mixture is obtained, and the solid-liquid is separated by plate and frame filtration to obtain a second solid. The second solid is added to water, the mass ratio of the solid to water is 1:6, after being kept at 140°C for 50 minutes, the temperature is cooled to 38°C, filtered, a solid is obtained, and the solid is dried to obtain a hexadecane dibasic acid product.

[0168] The process of cooling the decolorizing solution to 35°C is as follows: cooling from 82°C to 72°C, keeping at 72°C for 1 hour, and then cooling to 35°C. 82°C to 72°C: the average cooling rate is 4°C / h, 72°C to 35°C: the average cooling rate is 8°C / h.

[0169] Comparative Example 1

[0170] It is basically the same as Example 10, except that:

[0171] (1) heating the fermentation liquid to obtain a mixed liquid in which the dry weight of insoluble matter accounts for 4 wt %;

[0172] (2) filtering the mixed liquid to obtain a filtrate, decolorizing the filtrate, and subjecting the decolorized liquid to acidification, crystallization, and solid-liquid separation;

[0173] (3) Refining treatment.

[0174] In step (2):

[0175] a) the filtration is membrane filtration, wherein a ceramic membrane with a pore size of 0.05 micrometer is used for the membrane filtration, and the operating pressure is 0.5 MPa; activated carbon (iodine value is 850) is added to the filtrate obtained after filtration as a decolorizing agent, and the amount of activated carbon is 2% of the mass of the dodecanedioic acid contained in the filtrate, and the decolorization is carried out at 78° C. for 50 minutes;

[0176] b) subjecting the decolorized liquid to acidification crystallization and solid-liquid separation; wherein, during the acidification crystallization, sulfuric acid is used to adjust the pH value of the filtrate to 3.5, the temperature is directly lowered to 20° C., crystals are precipitated, and the first solid is obtained after solid-liquid separation by plate and frame filtration.

[0177] Step (3): Same as Example 10.

[0178] Table 1 Test data of long chain dibasic acid products

[0179]

[0180] Unless otherwise defined, the terms used in the present invention have the meanings commonly understood by those skilled in the art.

[0181] The embodiments described in the present invention are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. Those skilled in the art may make various other substitutions, changes and improvements within the scope of the present invention. Therefore, the present invention is not limited to the above embodiments, but is only limited by the claims.

Claims

1. A method for extracting and refining a long-chain dibasic acid, characterized in that: The method comprises the following steps: (1) heating the fermentation broth of the long-chain dibasic acid to reduce the content of insoluble matter in the fermentation broth to obtain a mixed liquid in which the dry weight ratio of the insoluble matter is less than 4 wt %; (2) filtering the mixed liquid to obtain a filtrate, and subjecting the filtrate to an acidification crystallization treatment and a solid-liquid separation treatment with or without a decolorization treatment to obtain a first solid; (3) The first solid is subjected to a purification treatment.

2. The method according to claim 1, characterized in that The long-chain dibasic acid is selected from any one of sebacic acid, undecanedioic acid, dodecanedioic acid, tridecanedioic acid, tetradecanedioic acid, pentadecanedicarboxylic acid, hexadecanedioic acid, heptadecanedioic acid, octadecanedicarboxylic acid, and 9-ene-octadecanedicarboxylic acid, or a combination of two or more thereof.

3. The method according to claim 1, characterized in that The filtration in step (2) is membrane filtration; Preferably, 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 micrometer.

4. The method according to claim 1, characterized in that: The decolorization treatment in step (2) uses activated carbon as a decolorizing agent, and the iodine value of the activated carbon is above 400; and / or, the acidification crystallization treatment in step (2) includes: adjusting the pH value of the filtrate or the decolorized liquid obtained after the filtrate is decolorized to 2-4, heating it to 80-130°C, keeping it warm for 10-120 minutes, and then cooling it to 25-40°C.

5. The method according to claim 1, characterized in that The refining treatment in step (3) includes any one or a combination of two or more of recrystallization, melt crystallization, extraction, distillation, chromatographic separation, and water treatment.

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

7. The method according to claim 6, characterized in that The organic solvent is selected from one or a combination of two or more of organic acids, alcohols, esters, and alkanes; and / or, The concentration of the organic solvent is ≥90%, further ≥95%, further ≥97%, and further ≥99%.

8. The method according to claim 6 or 7, characterized in that: The organic solvent is selected from any one of acetic acid, acetic acid (C1-C4) alcohol ester, and C3-C8 alcohol, or a combination of two or more thereof.

9. The method according to claim 6, characterized in that The decolorization treatment uses activated carbon as a decolorizing agent, and the iodine value of the activated carbon is above 400.

10. The method according to claim 6, characterized in that The refining treatment in step (3) further includes: washing and / or drying the second solid.

11. The method according to claim 6 or 10, characterized in that: The refining treatment in step (3) further comprises the following steps: placing the second solid in water at 70 to 150° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation to obtain a third solid.

12. The method according to claim 6 or 10, characterized in that: The refining treatment in step (3) further comprises the following steps: placing the second solid in water at 90 to 150° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation to obtain a third solid.

13. The method according to claim 6 or 10, characterized in that: The refining treatment in step (3) also includes the following steps: placing the second solid in water at 70 to 100° C., keeping the temperature for 15 to 150 minutes, then cooling the temperature to 20 to 65° C., and then performing solid-liquid separation to obtain a third solid.

14. The method according to claim 1, 5 or 6, characterized in that: After completing step (3), repeat the operation process and conditions of step (3) one more time.

15. The method according to claim 1, characterized in that The pH value of the fermentation liquid is 2-12.

16. The method according to claim 15, characterized in that The pH value of the fermentation broth is adjusted to 2-12 by adding acid and / or alkali.

17. The method according to claim 16, characterized in that The alkali includes sodium hydroxide, potassium hydroxide, ammonia water, liquid ammonia, ammonia gas or a mixed alkali containing at least two of them; preferably, the alkali exists in the form of an aqueous solution with a concentration of 10wt% to 40wt%, further 15wt% to 35wt%, further 15wt% to 30wt%.

18. The method according to claim 16, characterized in that 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 them.

19. A long-chain dibasic acid product, wherein: The purity is greater than 98.5%, and / or the ash content is less than 50 ppm, and / or the iron ion content is less than 3 ppm, and / or the nitrogen content is less than 30 ppm, and / or the light transmittance at 440 nm is greater than 97%; Preferably, the purity is >99%, and / or the ash content is <35 ppm, and / or the iron ion content is <2 ppm, and / or the nitrogen content is <25 ppm, and / or the transmittance at 440 nm is >98%.

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