Continuous process method for preparing hydroquinone

A technology of hydroquinone and a process method is applied in the field of preparation of hydroquinone, and can solve the problems of affecting the stability of hydrolyzed base acid, large amount of acid circulation in hydrolysis reaction, and high requirements on the material of hydrolysis kettle, so as to reduce equipment investment. , to achieve the effect of waste acid discharge and reduce equipment volume

Active Publication Date: 2015-04-01
JIANGSU YANGNONG CHEM GROUP +1
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

But this process also has the following problems: 1. the hydrolysis reaction acid circulation is large, the reactor volume is large, and the equipment investment is large; 2. the hydrolysis reaction temperature is high (106-108 ℃), the sulfuric acid concentration is high (30%), and the corrosion is large , the material requirements of the hydrolysis kettle are high; ③The sodium salt generated by the diazonium reaction will be enriched in the acid after entering the hydrolysis reaction, which will affect the stability of the hydrolysis base acid. acid treatment

Method used

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  • Continuous process method for preparing hydroquinone
  • Continuous process method for preparing hydroquinone
  • Continuous process method for preparing hydroquinone

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0038] 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% sodium nitrite dropwise Aqueous solution 48g (0.275mol), dripping time 30-45min, after dropping, keep warm for 0.5hr, add 1.5g urea, stir for 15min, when the release of nitrogen is not obvious, add 1.5g 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.

[0039] Reaction-extraction: using attached figure 1 Process, add 250g of 30% copper sulfate and 25g of MIBK into a 1000ml four-necked bottle, start stirring and raise the temperature to 85-88°C, add 235g of diazonium solution dropwise for 1hr, after the addition is completed, keep warm at 85-88°C for 2hr, and the resulting mixture is used as Bottom material for continuous tank reac...

Embodiment 2-6

[0041] The preparation method is the same as in Example 1, except that the concentration of copper sulfate in the hydrolysis is changed. The copper in the hydrolysis is all calculated in the form of copper sulfate)

[0042]

[0043] The concentration of hydrolyzed copper sulfate is higher than 30%, and the yield is 90-92%; when the yield drops to 20%, the yield shows an obvious downward trend.

Embodiment 7

[0045] Hydroquinone preparation method carries out according to the following steps:

[0046] 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% sodium nitrite dropwise Aqueous solution 48g (0.275mol), dripping time 30-45min, after dropping, keep warm for 0.5hr, add 1.5g urea, stir for 15min, when the release of nitrogen is not obvious, add 1.5g 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.

[0047] Reaction-extraction: using attached figure 2 Process, add 1700g of 30% copper sulfate solution to a tower reactor with a volume of 1300ml, preheat to 88°C; continuously feed MIBK from the bottom, with a flow rate of 77.82g / hr; feed 30% copper sulfate in the middle, with a flow rate of 194...

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Abstract

The present invention relates to a continuous process method for preparing hydroquinone. The method comprises the following steps: (1) adding a sodium nitrite aqueous solution to a sulfuric acid solution of para-aminophenol in a dropwise manner to carry out a diazotization reaction to obtain a dark brown diazo solution; (2) continuously feeding methyl isobutyl ketone from the bottom, continuously feeding a copper sulfate solution from the middle part, collecting extraction residue water from the bottom, collecting an extraction oil layer from the upper overflow port, adjusting flow and in-out balance, and then continuously feeding a diazo solution from the middle part, wherein the extraction oil layer is subjected to precipitation, decoking and crystallization to obtain the hydroquinone finished product.

Description

technical field [0001] The present invention relates to the preparation method of Hydroquinone (HQ for short). Background technique [0002] Hydroquinone, also known as hydroquinone (HQ), 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. Hydroquinone is widely used as an important raw material, intermediate and auxiliary agent for medicine, pesticide, dye and rubber, etc. It is mainly used for developer, anthraquinone dye, azo dye, rubber antioxidant and monomer polymerization inhibitor, Food stabilizers and paint antioxidants, petroleum anticoagulants, synthetic ammonia catalysts, etc. At present, the application field of hydroquinone is gradually expanding. In addition to the application in the traditional field, there are also new developments in the fields of chemical fertilizers, water treatment, and liquid crystal polymers. In addition, it can also be processe...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C07C39/08C07C37/045
Inventor 史雪芳徐林程晓曦顾志强丁克鸿田宇王丹肖锋陈宏飞
Owner JIANGSU YANGNONG CHEM GROUP
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