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Preparation method of 2,6-dihydroxy naphthalene

A technology of dihydroxynaphthalene and sodium naphthalene disulfonate, applied in the preparation of organic compounds, chemical instruments and methods, organic chemistry, etc., can solve problems such as impact, and achieve the effect of high product purity

Inactive Publication Date: 2011-10-19
NANTONG BAISHENG CHEM
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  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Since 2,6-naphthalene disulfonate sodium (potassium) generated during high-temperature alkali fusion with mixed alkali is easily oxidized into tar, which directly affects the selectivity of 2,6-dihydroxynaphthalene

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0008] In a 2000L stainless steel reactor, add 90% KOH 523g, 98% NaOH 523g, heat to 260°C, add 332g of sodium 2,6-naphthalene disulfonate (content 75%, purity 94%) and phenol 52g, heat up to 345 React for 3 hours between ~355°C, after the reaction is over, cool the material to 260~270°C, add 4000ml of water to dissolve the material, and then adjust the alkali fusion dilution to 1.17~1.19g / cm with water 3 Between them, use 38% sulfuric acid aqueous solution to neutralize until the pH value is 2~3, cool to 25°C, filter, and drain to obtain 253g of crude 2,6-dihydroxynaphthalene (organic matter content is 62%, 2,6 - The purity of dihydroxynaphthalene is 88.32%, and it has been refined into a fine product with a purity of more than 98%.).

[0009] By comparison, in the case that other conditions are the same as those in the examples, no antioxidant phenol is added during the high-temperature alkali fusion process of 2,6-sodium naphthalene disulfonate and mixed alkali to obtain 206...

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Abstract

The invention discloses a preparation method of 2,6-dihydroxy naphthalene, which comprises the steps of: adding 98% of KOH and NaOH to a reaction kettle, heating, adding 2,6-naphthalenedisulfonic acid disodium salt and phenol, heating up to 345 to 355 DEG C and then performing reaction, cooling materials to 260 to 270 DEG C upon the completion of the reaction, adding water to dissolve the materials, then regulating an alkali fusion diluting material to a range from 1.17g / cm<3> to 1.19g / cm<3> with water, neutralizing with an sulfuric acid aqueous solution to the condition that the pH is 2 to 3, cooling, filtering and drying by pumping to obtain the crude 2,6-dihydroxy naphthalene. According to the method, a small quantity of phenol is added as an antioxidant during high temperature alkali fusion of 2,6-naphthalenedisulfonic acid disodium salt and mixed alkali, thus the generated 2,6-naphthalenediphenol sodium (potassium) is prevented from oxidation, the selectivity of the 2,6-naphthalenedisulfonic acid disodium salt is improved and the product purity is high.

Description

technical field [0001] The invention relates to a preparation method of 2,6-dihydroxynaphthalene. Background technique [0002] 2,6-Dihydroxynaphthalene is an important pharmaceutical intermediate. Since 2,6-naphthalene disulfonate sodium (potassium) generated during high-temperature alkali fusion with mixed alkali is easily oxidized into tar, which directly affects the selectivity of 2,6-dihydroxynaphthalene . Contents of the invention [0003] The purpose of the present invention is to provide a kind of preparation method of 2,6-dihydroxynaphthalene with high product purity. [0004] Technical solution of the present invention is: [0005] A preparation method for 2,6-dihydroxynaphthalene, which is characterized in that: in a reaction kettle, add 90% KOH and 98% NaOH, heat, add 2,6-sodium naphthalene disulfonate and phenol, and heat up to 345- React between 355°C, the reaction is over, the material is cooled to 260~270°C, add water to dissolve the material, and then ...

Claims

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Application Information

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IPC IPC(8): C07C39/14C07C37/04C07C37/88
Inventor 许庆丰袁仲飞张天永
Owner NANTONG BAISHENG CHEM
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