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CN-122010748-A - Method for purifying 3,3' -diaminobenzidine by crystallization

CN122010748ACN 122010748 ACN122010748 ACN 122010748ACN-122010748-A

Abstract

The invention relates to the technical field of 3,3' -diaminobenzidine preparation, and discloses a method for purifying 3,3' -diaminobenzidine by crystallization, which comprises the following steps of (1) dissolving a 3,3' -diaminobenzidine crude product in a good solvent; the method comprises the steps of (1) carrying out solid-liquid separation on a dissolved 3,3' -diaminobenzidine crude product, contacting the dissolved 3,3' -diaminobenzidine crude product with activated carbon, obtaining a solution through solid-liquid separation, (3) adding at least part of a solvent into the solution obtained in the step (2), carrying out crystal growth, adding the rest solvent after crystal growth, and carrying out first aging, and (4) cooling a product obtained by the first aging, carrying out second aging, solid-liquid separation, washing and drying at the temperature, wherein the cooling rate is 0.1-0.4 ℃ per minute. The method can obtain the 3,3' -diaminobenzidine product with high purity and high yield.

Inventors

  • HAO HONGXUN
  • LI JI
  • ZHAO JIAWEI
  • WANG AILIAN
  • ZHANG LONGGUI
  • WANG TING
  • WANG NA
  • LI JING
  • WU JIANING
  • HE WEN

Assignees

  • 中国石油化工股份有限公司
  • 中石化(北京)化工研究院有限公司

Dates

Publication Date
20260512
Application Date
20241111

Claims (10)

  1. 1. A method for the crystallization and purification of 3,3' -diaminobenzidine, comprising the steps of: (1) Dissolving a crude 3,3' -diaminobenzidine product in a good solvent, wherein the good solvent comprises at least one of an organic matter containing nitrogen, an organic matter containing sulfur and an organic matter containing oxygen; (2) The dissolved 3,3' -diaminobenzidine crude product is contacted with active carbon, and then is subjected to solid-liquid separation to obtain a solution; (3) Adding at least part of the solvent into the solution obtained in the step (2) for crystal growth, adding the rest solvent after crystal growth, and then performing first aging, wherein the solvent comprises water and/or monohydric alcohol; (4) And cooling the product obtained by the first aging, and performing the second aging, solid-liquid separation, washing and drying at the temperature, wherein the cooling rate is 0.1-0.4 ℃ per minute.
  2. 2. The method of claim 1, wherein in step (1), the dissolution temperature is 25-35 ℃.
  3. 3. The method of claim 1, wherein the good solvent comprises at least one of N, N-dimethylformamide, N-dimethylacetamide, dimethylsulfoxide, and tetrahydrofuran; And/or, the amount of the good solvent used is 10 to 35mL per 12g of crude 3,3' -diaminobenzidine.
  4. 4. The process according to claim 1, wherein the amount of the activated carbon is 0.01 to 1g per 12g of the crude 3,3' -diaminobenzidine; And/or in the step (2), the contact condition comprises a temperature of 5-35 ℃ and a time of 0.5-1h.
  5. 5. The method of claim 1, wherein the elution agent is a C1-C5 monohydric alcohol and/or water, preferably at least one of methanol, ethanol, water, isopropanol and n-propanol.
  6. 6. The method of claim 1, wherein in step (3), the volume ratio of the total amount of the elution agent to the amount of the good solvent is 1-4:1; And/or, in the step (3), the at least part of the solvent is used in an amount such that crystals of the solution obtained in the step (2) start to precipitate; And/or, the adding temperature of the solvent is 5-30 ℃; And/or, the solvent is added in a dropwise manner.
  7. 7. The method of claim 1, wherein the conditions for growing the crystals comprise a temperature of 5-35 ℃ for 0.5-1.5 hours.
  8. 8. The method of claim 1, wherein the first aging condition comprises a temperature of 5-35 ℃ and a time of 0.5-2 hours.
  9. 9. The method of claim 1, wherein in step (4), the second aging condition comprises a temperature of 0-5 ℃ and a time of 0.5-2 hours.
  10. 10. The method according to claim 1, wherein the washing employs a detergent of C1-C5 monohydric alcohol and/or water, preferably at least one of methanol, ethanol, water, isopropanol and n-propanol; And/or the drying condition comprises that under the vacuum condition, the temperature is 40-60 ℃ and the time is 3-8h.

Description

Method for purifying 3,3' -diaminobenzidine by crystallization Technical Field The invention relates to the technical field of preparation of 3,3 '-diaminobenzidine, in particular to a method for purifying 3,3' -diaminobenzidine by crystallization. Background 3,3' -Diaminobenzidine is an important monomer for high molecular polymers and can be used for preparing high molecular resins and fibers having excellent properties, such as polybenzimidazole and polyamide. Meanwhile, 3' -diaminobenzidine has mutagenicity, so that nucleic acid, protein and the like can be chemically stained. As an analytical detection reagent, it is commonly used for spectrophotometry to determine selenium content. The purity of the 3,3' -diaminobenzidine directly influences the accuracy of analysis and detection and the value and performance of subsequent synthesized products, so that the production scale of the 3,3' -diaminobenzidine is improved, and the 3,3' -diaminobenzidine is refined by developing and optimizing a crystallization process, thereby having important practical significance and wide development prospect. CN117756640A synthesizes 3,3' -diaminobenzidine by adopting a two-step heating method, wherein in the purification process, water which is 40-50 times of the mass of the crude product is required to be used for dissolving the 3,3' -diaminobenzidine, meanwhile, active carbon and antioxidant ammonium sulfate hydrochloride with the mass ratio of 1:1 are required to be added, the whole process is required to be protected by nitrogen due to the overhigh operation temperature, and the purification operation is required to be repeated for many times to obtain the high-purity 3,3' -diaminobenzidine, so that the total yield is not high. EP0522577B1 still requires a large amount of water as solvent in the process of purifying crude 3,3' -diaminobenzidine, and the dissolution temperature is above 100 ℃. US3943175 uses a large amount of acid and alkali to obtain a3, 3' -diaminobenzidine solid product through acid-base reaction and a large amount of boiling water dissolution and cooling, and the operation temperature is high and the purity of the product is not high. US3481984 uses sodium chloride as a flocculant and passes an aqueous solution of 3,3' -diaminobenzidine through an activated carbon column at 120-125 ℃ to remove insoluble colloidal impurities, which is costly and inefficient. In summary, 3' -diaminobenzidine is mostly purified by using water as a solvent, but because the solubility of 3,3' -diaminobenzidine in water is very low, a large amount of water is needed to be used at a high temperature of about 100 ℃ to dissolve the 3,3' -diaminobenzidine, and because 3,3' -diaminobenzidine is easy to oxidize and deteriorate at a high temperature, nitrogen protection is needed in the whole process, and multiple purifications are needed to obtain a high-purity 3,3' -diaminobenzidine product, so that the defects of low equipment utilization rate, high energy consumption, small single-batch processing capacity, low yield and the like are overcome. Disclosure of Invention The invention aims to overcome the problems in the prior art and provide a method for purifying 3,3' -diaminobenzidine by crystallization. In order to achieve the above object, the present invention provides a method for purifying 3,3' -diaminobenzidine by crystallization, comprising the steps of: (1) Dissolving a crude 3,3' -diaminobenzidine product in a good solvent, wherein the good solvent comprises at least one of an organic matter containing nitrogen, an organic matter containing sulfur and an organic matter containing oxygen; (2) The dissolved 3,3' -diaminobenzidine crude product is contacted with active carbon, and then is subjected to solid-liquid separation to obtain a solution; (3) Adding at least part of the solvent into the solution obtained in the step (2) for crystal growth, adding the rest solvent after crystal growth, and then performing first aging, wherein the solvent comprises water and/or monohydric alcohol; (4) And cooling the product obtained by the first aging, and performing the second aging, solid-liquid separation, washing and drying at the temperature, wherein the cooling rate is 0.1-0.4 ℃ per minute. Through the technical scheme, the invention has the following beneficial effects: (1) The 3,3' -diaminobenzidine crude product contains more impurities (mainly soluble biphenylamine compounds such as biphenylamine triamine or biphenylamine) and the impurities in the crude product are derived from an upstream process. According to the invention, the crystallization and purification are carried out by adopting a specific good solvent and a specific solvent, and meanwhile, the solvent is added twice and aged at different temperatures twice, so that the 3,3' -diaminobenzidine product with high purity and high yield can be obtained by the method. The method has the advantages of mild conditions, simple process, low energy consumption, no ne