CN-122010719-A - Treatment method of o-methyl phenylacetic acid mother liquor

Abstract

The invention relates to the technical field of industrial wastewater treatment, and particularly discloses a treatment method of o-methyl phenylacetic acid mother liquor. The invention provides a treatment method of o-methyl phenylacetic acid mother liquor, which sequentially comprises the steps of primary constant temperature crystallization, secondary multi-stage temperature control crystallization, bipolar membrane electrodialysis enrichment after secondary mother liquor alkalinity adjustment, concentrated solution decompression crystallization, three times of mother liquor decompression distillation recovery solvent and the like, realizes the graded recovery and the solvent recycling of the o-methyl phenylacetic acid, greatly reduces the resource waste and the wastewater discharge, has strong industrial applicability, meets the requirements of green chemical development, and has wide industrial application prospect in the field of o-methyl phenylacetic acid production mother liquor treatment.

Inventors

• ZHANG YU
• LIU YAPENG
• YIN ZHONGKAI
• LI YUNPENG
• ZHANG GAIFEI
• Wei xinjian
• Pang Ningmin
• WANG SHUANGLONG
• YIN GUOHUA
• HOU JINGJING
• DING XIAOQIANG

Assignees

• 河北诚信集团有限公司

Dates

Publication Date

20260512

Application Date

20260121

Claims (10)

1. 1. The method for treating the o-methyl phenylacetic acid mother liquor is characterized by comprising the following steps of: Step a, heating o-methyl phenylacetic acid mother liquor to dissolve the o-methyl phenylacetic acid contained in the o-methyl phenylacetic acid mother liquor, then cooling to 40-50 ℃, preserving heat for crystallization, and filtering to obtain primary o-methyl phenylacetic acid crystals and primary mother liquor; Step b, heating the primary mother liquor to dissolve residual o-methyl phenylacetic acid, then cooling to 35-40 ℃ at a first cooling rate, preserving heat for a first preset time, cooling to 30-35 ℃ at a second cooling rate, preserving heat for a second preset time, cooling to 25-30 ℃ at a third cooling rate, preserving heat for a third preset time, and filtering to obtain secondary o-methyl phenylacetic acid crystals and secondary mother liquor; Step c, regulating the pH value of the secondary mother liquor to be alkaline, then introducing the secondary mother liquor into a bipolar membrane electrodialysis device, and collecting an acid chamber solution to obtain an o-methyl phenylacetic acid enrichment solution; Step d, concentrating the o-methyl phenylacetic acid enrichment solution under reduced pressure to obtain o-methyl phenylacetic acid enrichment solution and a removal solvent, cooling the o-methyl phenylacetic acid enrichment solution to 4-5 ℃, preserving heat for crystallization, centrifuging, and washing to obtain tertiary o-methyl phenylacetic acid crystals and tertiary mother liquor; Step e, combining the tertiary mother liquor and the solvent removal, performing reduced pressure distillation, and collecting fractions to obtain recovered water and ethanol; Wherein the ionic membrane of the bipolar membrane electrodialysis device is alkali-resistant homogeneous-phase anion membrane-AHT, and the bipolar membrane is bipolar membrane-BPS-1.
2. 2. The method for treating a mother liquor of o-tolylacetic acid according to claim 1, wherein in the step a, the temperature is raised to 60 to 70 ℃ and/or In the step a, the heat preservation crystallization time is 1-2 h, and/or In step a, the pore size of the filter medium used for the filtration is 10-20 μm, and/or In the step a, a program cooling mode is adopted to cool to 40-50 ℃ with the cooling rate of 5-10 ℃ per hour.
3. 3. The method for treating an o-methylphenylacetic acid mother liquor according to claim 1, wherein in the step b, the temperature is raised to 60 ℃ to 70 ℃.
4. 4. The method for treating o-methylphenylacetic acid mother liquor according to claim 1, wherein in the step b, the first cooling rate is 4 ℃ per hour to 6 ℃ per hour, the first preset time is 3h to 5h, the second cooling rate is 2 ℃ per hour to 3 ℃ per hour, the second preset time is 1.5h to 2.5h, the third cooling rate is 1 ℃ per hour to 2 ℃ per hour, and the third preset time is 2.5h to 5h.
5. 5. The method for treating a mother liquor of o-methylphenylacetic acid according to claim 1, wherein in the step c, the alkalinity means a pH value of 9 to 12, and/or In the step C, the voltage of the bipolar membrane electrodialysis device is set to 10-20V, the current density is 10mA/cm 2 ~15mA/cm 2 , and the temperature is 25-30 ℃.
6. 6. The method for treating o-methylphenylacetic acid mother liquor according to claim 1, wherein in the step d, the pressure of the reduced pressure concentration is-0.085 MPa to-0.095 MPa and the temperature is 20 ℃ to 40 ℃.
7. 7. The method for treating an o-tolylacetic acid mother liquor according to claim 1, wherein in the step d, the o-tolylacetic acid concentrated solution is 40% -45% of the mass of the o-tolylacetic acid enriched solution.
8. 8. The method for treating o-methylphenylacetic acid mother liquor according to claim 1, wherein in the step d, the time of heat preservation and crystallization is 2-4 hours.
9. 9. The method for treating a mother liquor of o-methylphenylacetic acid according to claim 1, wherein in step d, the washing specifically includes the steps of: and washing and filtering the obtained solid by adopting ice water with the temperature of 8-10 ℃ and cold ethanol with the temperature of 8-10 ℃ in sequence.
10. 10. The method for treating an o-methylphenylacetic acid mother liquor according to claim 1, wherein in the step e, the pressure of the reduced pressure distillation is-0.085 MPa to-0.095 MPa and the temperature is 20 ℃ to 40 ℃.

Description

Treatment method of o-methyl phenylacetic acid mother liquor Technical Field The invention relates to the technical field of industrial wastewater treatment, in particular to a treatment method of o-methyl phenylacetic acid mother liquor. Background O-methyl phenylacetic acid (OMA for short) is an important organic synthesis intermediate, has irreplaceable key effects in the fields of medicine, pesticide and the like, and is a core raw material for synthesizing various high-added-value products such as ibuprofen, pyrethroid and the like. At present, the sodium cyanide method is widely used for producing o-methyl phenylacetic acid in industry, the process is mature and widely applied, and the core reaction process is that o-methyl chlorobenzyl and sodium cyanide (NaCN) are used as raw materials to carry out substitution reaction to generate o-methyl benzyl cyanide, and then the o-methyl benzyl cyanide is subjected to alkaline hydrolysis and acidification treatment to obtain the target product OMA. However, in the production of OMA by the sodium cyanide process, large amounts of production mother liquor are concomitantly produced. The prior recovery processing technology for OMA mother liquor has the following core problems: (1) The yield and purity of the target product are low, the yield of the target product is only 70% -80% by adopting a direct cooling crystallization method, a large amount of target product is still reserved in the mother liquor, waste is caused, although the solubility of OMA in the mother liquor is low, OMA is easy to separate out along with other impurities in the mother liquor in the crystallization process, the purity of the recovered product is low, a large amount of energy consumption and reagent are required for recovering the mother liquor, the economic feasibility of the recovery process is poor, most enterprises choose to discard the recovery, waste of the target product is caused, and the pollutant load of subsequent wastewater treatment is increased. (2) The method has the advantages of high environmental protection pressure and high treatment cost, the acid precipitation method realizes product separation by adding sulfuric acid for acidification, but the process can generate a large amount of high-salt wastewater containing sodium sulfate, the subsequent treatment has high difficulty and high cost, secondary pollution is easy to cause, the solvent extraction method mainly adopts ethyl acetate as an extractant, the product separation efficiency can be improved to a certain extent, the problems of high solvent consumption and high operation cost exist, the purity of the product is further influenced by solvent residues, and the environmental protection burden is increased due to the recovery and treatment of the solvent. (3) The solvent in the mother liquor is not effectively recycled, and most of the prior art does not realize the effective recycling and cyclic utilization of the solvent such as water, ethanol and the like in the mother liquor, thereby not only causing resource waste, but also causing larger wastewater discharge. In summary, the existing OMA mother liquor treatment technology generally has the problems of low recovery yield and purity, high environmental protection pressure, resource waste and the like, and is difficult to adapt to the current requirements of green chemical development. Therefore, the o-methyl phenylacetic acid mother liquor treatment method which can efficiently enrich and recycle OMA, reduce environmental protection load and recycle solvent is developed, and has important practical significance and industrial application value. Disclosure of Invention Aiming at the problems of low yield and purity, high environmental protection pressure, resource waste and the like of the recovered OMA mother liquor commonly existing in the prior OMA mother liquor treatment technology, the invention provides a treatment method of o-methyl phenylacetic acid mother liquor. The method mainly comprises the steps of gradient cooling crystallization, alkaline adjustment electrolysis enrichment of o-methyl phenylacetic acid, decompression concentration, sectional washing and the like to obtain high-purity o-methyl phenylacetic acid, and the residual mother liquor after the o-methyl phenylacetic acid is separated is subjected to decompression distillation to recover ethanol and water, so that the recycling of effective components in OMA mother liquor is realized, and the method has higher economic benefit and environmental benefit. In order to solve the technical problems, the technical scheme provided by the invention is as follows: a method for treating o-methyl phenylacetic acid mother liquor comprises the following steps: Step a, heating o-methyl phenylacetic acid mother liquor to dissolve the o-methyl phenylacetic acid contained in the o-methyl phenylacetic acid mother liquor, then cooling to 40-50 ℃, preserving heat for crystallization, and filtering to obt