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CN-122010895-A - Preparation method of N-hydroxyethyl-3, 4-methylenedioxy aniline

CN122010895ACN 122010895 ACN122010895 ACN 122010895ACN-122010895-A

Abstract

The invention relates to a preparation method of N-hydroxyethyl-3, 4-methylenedioxyaniline, which comprises the following steps of (1) condensation reaction of piperine and ethylene carbonate serving as starting materials in a high-boiling-point ether solvent, (2) distillation of the reaction liquid obtained in the step (1) under reduced pressure to recover the solvent, thus obtaining crude N-hydroxyethyl-3, 4-methylenedioxyaniline, and (3) purification of the crude N-hydroxyethyl-3, 4-methylenedioxyaniline, and post-treatment of the crude N-hydroxyethyl-3, 4-methylenedioxyaniline to obtain refined N-hydroxyethyl-3, 4-methylenedioxyaniline. The invention improves the quality of the product, reduces environmental pollution, has the characteristics of green, low cost, simple operation and the like, and ensures that the product production is clean, safe and environment-friendly, so that the product is more suitable for mass production.

Inventors

  • LIU FENG
  • TENG PENG
  • PAN ZHIJUN

Assignees

  • 浙江鼎龙科技股份有限公司
  • 内蒙古鼎利科技有限公司

Dates

Publication Date
20260512
Application Date
20260410

Claims (9)

  1. 1. A method for preparing N-hydroxyethyl-3, 4-methylenedioxyaniline, which is characterized by comprising the following steps: (1) Condensation reaction, namely taking piperine and ethylene carbonate as starting materials, and carrying out condensation reaction in an ether solvent; (2) Distilling the reaction liquid obtained in the step (1) under reduced pressure to recover the solvent to obtain a crude product of the N-hydroxyethyl-3, 4-methylenedioxy aniline; (3) Purifying, namely, post-treating the crude product of the N-hydroxyethyl-3, 4-methylenedioxyaniline to obtain a refined product of the N-hydroxyethyl-3, 4-methylenedioxyaniline.
  2. 2. The method for producing N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 1, wherein in the step (1), the ether solvent is diethylene glycol dimethyl ether.
  3. 3. The method for producing N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 1, wherein in the step (1), the reaction temperature is controlled to be 120 to 170 ℃ and the reaction time is controlled to be 7 to 13 hours.
  4. 4. The preparation method of N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 1, wherein the condensation reaction is performed under the action of a catalyst, and the catalyst is used in an amount of 0.1-5% by mass of piperonyl amine.
  5. 5. The method for preparing N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 4, wherein the catalyst is one or more of trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, phosphotungstic acid and NaY molecular sieves.
  6. 6. The method for preparing N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 1, wherein the molar ratio of piperonyl amine to ethylene carbonate is 1:1.02-1.16.
  7. 7. The process for the preparation of N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 1, wherein in step (3) the post-treatment is recrystallisation.
  8. 8. The method for producing N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 7, wherein the solvent for recrystallization is an ethanol-water solution or a methanol-water solution.
  9. 9. The preparation method of N-hydroxyethyl-3, 4-methylenedioxyaniline according to claim 2, wherein the amount of diethylene glycol dimethyl ether is 5-15 times of the mass of piperonyl amine.

Description

Preparation method of N-hydroxyethyl-3, 4-methylenedioxy aniline Technical Field The invention relates to a preparation method of a chemical intermediate, in particular to a preparation method of N-hydroxyethyl-3, 4-methylenedioxy aniline. Background N-hydroxyethyl-3, 4-methylenedioxyaniline is an important chemical and dye intermediate, is used as a coupling body component of a high-grade oxidant, is compounded with a main intermediate component commonly used, and can produce hair with rich color tone from deep yellow to olive through oxidative coupling. Oxidative dyes for dyeing hair must meet a number of requirements in addition to the desired intensity of dyeing. For example, from a toxicological and dermatological point of view, the dyes must be safe and the dyeing achieved must have good light fastness, permanent wave fastness, acid resistance and rubbing fastness. In any case, such staining must remain stable for at least 4-6 weeks without the action of light, friction and chemicals. Furthermore, it is necessary to create a wide range of different color nuances by combining suitable developers and couplers. N-hydroxyethyl-3, 4-methylenedioxyaniline, whose methylenedioxy can enhance the stability of a conjugated system, and hydroxyethyl provides an anchor point for water-soluble groups and subsequent derivative reactions, has obvious influence on the color light and fastness after dyeing, and is one of the varieties with the most development prospect in the international dyeing market at present. The report on the preparation method of the N-hydroxyethyl-3, 4-methylenedioxyaniline is less, the main synthesis method at present takes piperine as a starting material, and the piperine is condensed with chloroethyl chloroformate and then subjected to cyclization and hydrolysis to prepare the N-hydroxyethyl-3, 4-methylenedioxyaniline, and the preparation method comprises the following steps: the method has longer steps, simultaneously generates a large amount of salt-containing wastewater, and has higher price and toxicity of the raw material chloroethyl chloroformate. In addition, the literature reports that piperine is used as a starting material and is condensed with bromoethanol or chloroethanol in one step to prepare a target compound, the method has shorter steps, but the used material bromoethanol or chloroethanol has higher toxicity, in addition, the selectivity of the reaction is poorer, the quality of the product is poorer, and the total yield of the product is only about 50 percent. Disclosure of Invention In order to overcome the defects in the prior art, the invention provides a preparation method of the N-hydroxyethyl-3, 4-methylenedioxy aniline, which is green, safe and low in cost. In order to achieve the aim of the invention, the invention adopts the following technical scheme: a method for preparing N-hydroxyethyl-3, 4-methylenedioxy aniline, comprising the following steps: (1) Condensation reaction, namely taking piperine and ethylene carbonate as starting materials, and carrying out condensation reaction in an ether solvent; (2) Distilling the reaction liquid obtained in the step (1) under reduced pressure to recover the solvent to obtain a crude product of the N-hydroxyethyl-3, 4-methylenedioxy aniline; (3) Purifying, namely, post-treating the crude product of the N-hydroxyethyl-3, 4-methylenedioxyaniline to obtain a refined product of the N-hydroxyethyl-3, 4-methylenedioxyaniline. The ether solvent of the invention is selected from high boiling point ether solvents with boiling point more than or equal to 150 ℃, and preferably, in the step (1), the ether solvent is diethylene glycol dimethyl ether. The synthetic route of the invention is as follows: Preferably, in the step (1), the reaction temperature is controlled to be 120-170 ℃ and the reaction time is controlled to be 7-13 h. Less than 120 ℃ react incompletely and more than 170 ℃ may produce N, N-dihydroxyethyl by-product. Preferably, the condensation reaction is carried out under the action of a catalyst, and the dosage of the catalyst is 0.1-5% of the mass of piperonyl amine. Preferably, the catalyst is one or more than two of trifluoroacetic acid, methanesulfonic acid, p-toluenesulfonic acid, phosphotungstic acid and NaY molecular sieves. Preferably, the molar ratio of piperonyl amine to ethylene carbonate is 1:1.02-1.16. The excess of the ethylene carbonate is 0.02-0.16 mol, so that complete reaction of piperonyl amine can be promoted, and the post-treatment difficulty can be increased due to excessive excess. Preferably, in step (3), the post-treatment is recrystallisation. Preferably, the solvent for recrystallization is an ethanol-water solution or a methanol-water solution. Preferably, the dosage of the diethylene glycol dimethyl ether is 5-15 times of the mass of the piperonyl amine. The invention has the beneficial effects that: The invention improves the quality of the product, reduces environmental pollution, has the c