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Hydroquinone synthesis method

A technology of hydroquinone and synthesis method, which is applied in chemical instruments and methods, preparation of organic compounds, organic chemistry, etc. It can solve problems such as high temperature, large amount of tar, harsh reaction conditions, etc., and achieve the effect of process cleaning and environmental protection

Inactive Publication Date: 2015-07-01
JIANGSU YANGNONG CHEM GROUP +2
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  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The disadvantages of this process are: ① more tar is generated during the reaction; ② harsh reaction conditions: high temperature, strong acidic conditions
There are major problems in this process: 1. the amount of tar is large in the reaction process; 2. a large amount of ammonium sulfate (hydrogen) black waste water is produced; 3. the reaction yield is about 70%, and the total yield after refining and purifying is only 55-60%; 4. the reaction conditions are harsh: High temperature, high pressure, strong acid
However, there are disadvantages in this process: the sodium salt generated by the diazonium reaction enters the hydrolysis reaction and is enriched in the acid. When the sodium salt in the acid reaches a certain content, the reaction yield will decrease, which will affect the stability of the hydrolyzed bottom acid, and it needs to be discharged regularly. Salt-containing waste acid, application of maintenance acid

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0034] Example 1 (reaction part)

[0035] Hydroquinone preparation method is carried out as follows:

[0036] Diazotization reaction: Add 245g of 15% sulfuric acid and 27.8g of 98% p-aminophenol for industrial products into a 1000mL reactor, stir and cool down to -5~0℃, add 87.3g of 40% nitrosylsulfuric acid solution dropwise, and add the time 1-1.5hr, keep warm for 0.5hr after dripping, 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 350-360g of diazonium solution, which was stored at 0°C.

[0037] Hydrolysis reaction: first add 1000g of 40% sulfuric acid to a 2000mL reactor, heat to 106-110°C, add the above diazo solution dropwise at around 0°C, add dropwise for 1-1.5hr, and keep warm at 106-110°C for 3-4hr, Obtain about 1350g of hydrolyzate.

[0038] Extraction: The hydrolyzed liquid is lowered ...

Embodiment 2-6

[0040] The preparation method is the same as in Example 1, except that the concentration of sulfuric acid in the diazonium reaction is changed.

[0041]

Embodiment 7-12

[0043] The preparation method is the same as in Example 1, except that the temperature of the diazonium reaction is changed.

[0044]

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Abstract

The invention discloses a preparation method of hydroquinone (called as HQ for short). The preparation method comprises 1, diazotization reaction, 2, hydrolysis reaction, 3, extraction reaction and 4, purification reaction. Nitroso-sulfuric acid is used for the hydroquinone diazotization reaction so that the whole reaction system does not contain waste acid and through simple treatment, the hydrolyzed waste acid can be recycled and thus the preparation method is clean and environmentally friendly, does not produce a sodium salt in the reaction process and guarantees acid recycle.

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, which is widely used as an important raw material, intermediate and auxiliary agent for medicine, pesticides, dyes and rubber. Quinone dyes, azo dyes, rubber antioxidants and monomer polymerization inhibitors, food stabilizers and coating antioxidants, petroleum anticoagulants, etc. At present, the application fields of hydroquinone are gradually expanding. In addition to the application in traditional fields, new developments have also been made in fields such as chemical fertilizers, water treatment, and liquid crystal polymers. In the past 10 years, researchers have paid more attention to the research on the production process of hydroquinone and other aspects. [0003] There are many ways to prepare HQ, generally using aniline oxidation and pheno...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C37/04C07C39/08
CPCC07C37/04C07C39/08
Inventor 孙诚徐林丁克鸿顾志强李明曹美荣马庆炎
Owner JIANGSU YANGNONG CHEM GROUP
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