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CN-121974798-A - Method for extracting and refining long-chain dibasic acid by adopting mixed solution of water-soluble organic solvent and water

CN121974798ACN 121974798 ACN121974798 ACN 121974798ACN-121974798-A

Abstract

The invention relates to a method for extracting and refining long-chain dibasic acid by adopting a mixed solution of a water-soluble organic solvent and water. The method comprises the steps of directly acidifying and filtering fermentation liquor to obtain a long-chain diacid filter cake containing fermentation thalli, heating and dissolving the filter cake in a mixed solution consisting of a water-soluble organic solvent and water, decoloring and filtering, cooling and crystallizing, separating and washing, and dehydrating and drying to obtain a long-chain diacid refined product meeting the high quality requirement. The invention has the advantages of short process route, low energy consumption, environmental protection and low cost.

Inventors

  • XU ZEGUI
  • MENG HONG
  • XU SHUYU
  • WANG JIHUA
  • Peng Zechi

Assignees

  • 北京原生界生物科技有限责任公司

Dates

Publication Date
20260505
Application Date
20260127

Claims (10)

  1. 1. A method for extracting and refining long-chain diacid by adopting a mixed solution of a water-soluble organic solvent and water, which is characterized in that fermentation liquor is directly acidified and filtered to obtain a long-chain diacid filter cake containing fermentation thalli, the filter cake is heated and dissolved in the mixed solution consisting of the water-soluble organic solvent and water, and a long-chain diacid refined product meeting the high quality requirement is obtained through decolorization and filtration, cooling and crystallization, separation and washing and dehydration and drying, and the method is characterized by comprising the following steps: s1, directly adding inorganic acid into a fermentation liquor stock solution for acidification, preserving heat, filtering, adding water into a filter cake for resuspension, and filtering to obtain a long-chain dibasic acid filter cake containing fermentation thalli; s2, adding a long-chain dibasic acid filter cake containing fermentation thalli into a mixed solution composed of water-soluble alcohols or nitrile organic solvents and water, heating for dissolution, decolorizing with activated carbon, filtering to obtain decolorized clear liquid, cooling for crystallization, performing solid-liquid separation, washing with water, and dehydrating and drying to obtain a long-chain dibasic acid refined product; The long-chain dibasic acid is a metabolite obtained by fermenting the microorganism by alkane, wherein the molecular general formula of the long-chain dibasic acid is C n H 2n-2 O 4 , and n is 10-18.
  2. 2. The method for extracting and refining long-chain dibasic acid by using a mixed solution of a water-soluble organic solvent and water according to claim 1, wherein the stock solution of the fermentation broth is a fermentation broth after fermentation, and the pH value is 5.0-8.5.
  3. 3. The method for extracting and refining long-chain dibasic acid by using a mixed solution of a water-soluble organic solvent and water according to claim 1, wherein the acidification temperature is 20-90 ℃, the pH value of an acidification end point is 3.0-5.0, the acidification heat preservation time is 1.0-4.0 h, and the inorganic acid is at least one of sulfuric acid, hydrochloric acid, phosphoric acid and the like.
  4. 4. The method for extracting and refining long-chain diacid by adopting the mixed solution of the water-soluble organic solvent and water, which is disclosed in claim 1, is characterized in that the filter cake in S1 refers to a wet filter cake containing fermentation thalli, impurities and diacid or a filter cake after drying, namely a long-chain diacid filter cake containing fermentation thalli for short, and the water is added into the filter cake for resuspension, wherein the water consumption is 3-8 times of the mass of the filter cake.
  5. 5. The method for extracting and refining long-chain dibasic acid by using mixed solution of water-soluble organic solvent and water according to claim 1, wherein the water-soluble alcohols such as ethanol and isopropanol and the like in S2, and the water-soluble nitriles such as acetonitrile and the like are mixed solution of the water-soluble organic solvent and water, and the water-soluble organic solvent accounts for 50-95% of the volume of the mixed solution.
  6. 6. The method for extracting and refining long-chain dibasic acid by using a mixed solution of a water-soluble organic solvent and water, according to claim 1, wherein the concentration of the long-chain dibasic acid in the mixed solution is 150-400 g/L, and the heating and dissolving temperature of the long-chain dibasic acid is 40-85 ℃.
  7. 7. The method for extracting and refining long-chain dibasic acid by adopting the mixed solution of the water-soluble organic solvent and water, which is disclosed in claim 1, is characterized in that the activated carbon decolorization and filtration step S2 is that the activated carbon is added into the long-chain dibasic acid filter cake for the first time for decolorization, wherein the activated carbon is 2.0-6.0% (w/w) of the dry mass of the filter cake, the first time is obtained by heat preservation decolorization and filtration, the second time is obtained by adding the activated carbon which is 2.0-6.0% (w/w) of the dry mass of the filter cake into the first time of decolorization, the second time is obtained by heat preservation decolorization and filtration, and the heat preservation and decolorization time is 15-100 minutes.
  8. 8. The method for extracting and refining long-chain dibasic acid by adopting the mixed solution of the water-soluble organic solvent and water, which is disclosed in claim 1, is characterized in that the temperature of S2 is reduced and crystallized, the temperature is slowly reduced above the crystallization point, the temperature reduction speed is 0.5-5 ℃ per hour, the temperature of the crystallization point is kept for 0.5-2.0 hours, the temperature reduction speed is 8-15 ℃ per hour in other time periods, the end point temperature is 20-40 ℃, the temperature is kept for 1.0-4.0 hours, and the crystallization material is obtained by solid-liquid separation.
  9. 9. The method for extracting and refining long-chain dibasic acid by using a mixed solution of a water-soluble organic solvent and water according to claim 1, wherein the water is added for washing in the step S2, and the washing water consumption is 3-6 times of the mass of the filter cake.
  10. 10. The method for extracting and refining long-chain dibasic acid by using mixed solution of water-soluble organic solvent and water according to claim 1, wherein the drying equipment of S2 is a biconical dryer, a roller dryer, a hollow blade dryer, an air flow dryer and the like, and the drying temperature is 60-120 ℃.

Description

Method for extracting and refining long-chain dibasic acid by adopting mixed solution of water-soluble organic solvent and water Technical Field The invention relates to preparation of long-chain dibasic acid, in particular to a method for extracting and refining long-chain dibasic acid by adopting a mixed solution of a water-soluble organic solvent and water. Background The long chain dibasic acid is aliphatic dibasic acid (DCn or DCA for short) containing more than 10 carbon atoms in a carbon chain, and the aliphatic dibasic acid comprises saturated and unsaturated dibasic acid, is a fine chemical product with important and wide industrial application, and is an important raw material for synthesizing high-grade perfume, high-performance nylon engineering plastics, high-grade nylon hot melt adhesive, high-temperature dielectric medium, high-grade paint and coating, high-grade lubricating oil, cold-resistant plasticizer, resin, medicine, pesticide and the like in the chemical industry. In the prior art, in the process of producing long-chain diacid by utilizing a microbial fermentation method, firstly, the pH value of fermentation liquor is adjusted by adding alkali, so that long-chain diacid which is insoluble in water is changed into long-chain diacid salt which is soluble in water, bacterial cells are filtered and sterilized by a membrane filter, decolorization and filtration, acidification and filtration, dehydration and drying are carried out, and a long-chain diacid crude product is obtained, and the dried diacid crude product is refined in water or an organic solvent, so that a long-chain diacid refined product is obtained. Chinese patent CN103030550a discloses a method for purifying and refining long chain dibasic acids and salts thereof without using an organic solvent. And (3) performing acidification precipitation on the fermentation broth after removing thalli to obtain a crude product of the dibasic acid, adding alkali into water to perform heating dissolution, decoloring and filtering, adding the acid to perform acidification again, centrifuging, washing with water until the dibasic acid precipitate is neutral, adding water with the mass 3-20 times that of the dibasic acid to perform resuspension, heating a mixture of water and the dibasic acid at high pressure above the melting point temperature of the dibasic acid for 20-30 min, slowly cooling to room temperature, and filtering and separating to obtain long-chain dibasic acid crystals. Because the solubility of the long-chain dibasic acid in water is low, alkali is added in the refining process to form long-chain dibasic acid salt for purification, the method does not use an organic solvent, the production environment is friendly, but the acid and alkali consumption is large, the wastewater discharge amount is large, the production cost is high, and the product quality is difficult to meet the polymerization grade requirement. Chinese patent CN102911036a discloses a process for obtaining high purity dicarboxylic acids. Comprises the steps of heating and inactivating the terminated fermentation liquor, filtering and sterilizing, acid precipitating and crystallizing, filtering, dissolving an ether organic solvent, separating an organic phase from a water phase, decoloring and adsorbing the organic phase, filtering, crystallizing and drying to obtain the dicarboxylic acid. The method adopts a solvent extraction refining mode based on crude acid extraction, and although the quality of the obtained dicarboxylic acid is obviously improved, the dicarboxylic acid is sequentially subjected to multi-step operations such as aqueous phase dissolution, acid precipitation, drying and dehydration, organic phase heating and dissolution, cooling and precipitation, drying and the like, the process flow is long, and the energy consumption and the dicarboxylic acid loss are higher through the three heating processes. Chinese patent CN111349006A discloses a method for refining long-chain dicarboxylic acid, which comprises the steps of adding alkali into fermentation liquor after fermentation is finished to adjust the pH value to 9-10, heating, cooling, removing thalli by membrane filtration, adding inorganic acid, acidifying, filtering and drying to obtain crude acid. Adding low-carbon alcohol into crude acid at normal temperature for dissolution, filtering to remove solids, adding a large amount of water into filtrate to separate long-chain dibasic acid out of water phase, filtering and drying to obtain refined product. According to the method, long-chain dibasic acid is dissolved in low-carbon alcohol at room temperature for refining, the addition amount of the low-carbon alcohol is 10-20 times of the mass of crude acid, and water with the mass of more than 4 times of that of the low-carbon alcohol is added into the solution to separate out the long-chain dibasic acid, so that the separation of the long-chain dibasic acid is realized. However, the solubility