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Hydrolysis process for hydroquinone

A hydroquinone and process technology, which is applied in the field of hydroquinone hydrolysis process, can solve the problems of high sulfuric acid concentration, high corrosion, high material requirements, etc., and achieve the effect of clean and environmentally friendly process, increased production capacity, and reduced volume

Inactive Publication Date: 2012-10-24
JIANGSU YANGNONG CHEM GROUP +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0008] ①The hydrolysis reaction has a large amount of acid circulation, a large volume of the reaction kettle, and a large investment in equipment
[0009] ②The hydrolysis reaction temperature is high (106-108°C), the concentration of sulfuric acid is high (30%), the corrosion is high, the hydrolysis reaction conditions are harsh, and the material requirements of the kettle are high

Method used

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  • Hydrolysis process for hydroquinone
  • Hydrolysis process for hydroquinone
  • Hydrolysis process for hydroquinone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0026] 1. Diazotization reaction: Add 408g (0.625mol) of 15% sulfuric acid and 27.8g (0.25mol) of 98% p-aminophenol for industrial products into a 1000mL reactor, stir and cool down to -5~0°C, add 40% sulfuric acid dropwise Add 48g (0.275mol) of sodium nitrate aqueous solution, dropwise for 30-45min, keep warm for 0.5hr after dropping, add 1.5g of urea, stir for 15min, when the release of nitrogen is not obvious, add 1.5g of thiourea and stir for another 15min. The dropwise addition, heat preservation and feeding temperature were all kept at -5-5°C to obtain 470-480 g of dark brown diazonium liquid, which was stored at 0°C.

[0027] 2. Hydrolysis reaction: Add 42.5g (98%, 0.1875mol) of basic copper carbonate, 143.5g (98%, 0.5625mol) of copper sulfate pentahydrate, 314g of water and 200g of solvent n-butyl acetate or Methyl isobutyl ketone, heated to 85-88°C, then dropwise add the above diazonium solution at 0±0.5°C, dropwise for about 1 hr, and keep warm at 85-88°C for 1-1.5 h...

Embodiment 2 to 7

[0031] The preparation method is the same as in Example 1, except that the sulfuric acid concentration of the diazonium reaction is different. (All copper in hydrolysis is calculated as copper sulfate)

[0032]

[0033] The yield of diazoic acid is stable from 9 to 25%, and the yield is stable at 90 to 91%. When the acid concentration is reduced and increased, the yield shows a clear downward trend.

Embodiment 8 to 14

[0035] The preparation method is the same as in Example 1, except that the concentration of copper sulfate in the hydrolysis is changed. (All copper in hydrolysis is calculated as copper sulfate)

[0036]

[0037] The concentration of the hydrolyzed copper sulfate aqueous solution is higher than 30%, and the yield is 90-91%, and the yield shows an obvious downward trend when it drops to 20%.

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PUM

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Abstract

The invention discloses a hydrolysis process for hydroquinone and relates to a hydrolysis process during hydroquinone synthesis by subjecting p-aminophenol to diazotization and hydrolysis processes. The process includes: adding basic cupric carbonate, cupric sulfate and solvents into a hydrolysis reaction kettle, dropwise adding diazonium solution of 0+ / -0.5 DEG C obtained by subjecting sodium nitrite and dilute sulfuric acid to diazotization and performing hydrolysis reaction at a reaction temperature of 85 DEG C-88 DEG C. Raffinate phase does not generate waste acid, and the copper recovery rate reaches to more than 99.5%, so that a disadvantage of high copper price is made up; and sodium sulfate is obtained by means of concentration and crystallization of filtrate, concentrated water is used for preparing acid for diazo reaction, and crystallized mother solution of the sodium sulfate is used for preparing cupric sulfate solution for hydrolysis, so that clean production is realized.

Description

technical field [0001] The invention relates to the technical field of a method for preparing hydroquinone (HQ for short) from p-aminophenol, in particular to the hydrolysis process in which p-aminophenol is synthesized through diazotization and hydrolysis processes. Background technique [0002] Hydroquinone, also known as hydroquinone, is an important chemical raw material. In recent years, domestic demand for it has shown a growing trend, and the consumption field has expanded year by year. [0003] There are many synthetic methods of hydroquinone, among which the industrialized production mainly includes aniline oxidation method and phenol hydroxylation method. [0004] Chinese patent CN 200710163599.0 uses p-aminophenol to synthesize hydroquinone through diazotization and hydrolysis processes, uses sodium nitrite and dilute sulfuric acid for diazotization reaction, and then uses 30% sulfuric acid for hydrolysis reaction. [0005] Its reaction equation is: [0006] ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C39/08C07C37/045
Inventor 孙诚丁克鸿徐林顾志强李明马庆炎曹美荣
Owner JIANGSU YANGNONG CHEM GROUP
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