Method for synthesizing dyestuff intermediate H acid by naphthalene

A technology for synthesizing dyes and intermediates, applied in 1 field, can solve problems such as difficult treatment of high-salt COD wastewater, and achieve the effects of reducing secondary pollution, reducing emissions, and reducing reaction time

Active Publication Date: 2010-06-02
泰兴锦汇化工有限公司
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Problems solved by technology

This method is currently the main method for producing H acid in China. The method of alkali fusion is to make the sulfonic acid group on the T acid alkali-dissolved under alkaline co

Method used

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  • Method for synthesizing dyestuff intermediate H acid by naphthalene
  • Method for synthesizing dyestuff intermediate H acid by naphthalene
  • Method for synthesizing dyestuff intermediate H acid by naphthalene

Examples

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[0028] Example 1

[0029] Add 192 g of refined naphthalene and 792 g of 98% sulfuric acid into a three-necked flask, raise the temperature to 160° C., stir at this temperature for 1 hour, then raise the temperature to 175° C., and stir for 6 hours to carry out the reaction. After the reaction, cool to 40°C and add 135g of water to dilute the concentration of sulfuric acid to extract refined naphthalene 2,6-disulfonic acid, heat up to 65°C and filter to obtain 142g of naphthalene 2,6-disulfonic acid, then add 130g of water to the filtrate , dilute the sulfuric acid concentration to 40%, extract naphthalene-2,7-disulfonic acid, cool to 30°C and filter to obtain 180g naphthalene-2,7-disulfonic acid.

[0030] In addition, dissolve the previously fractionated naphthalene-2,6-disulfonic acid into 50 g of 80% sulfuric acid, add 15 g of water, adjust the sulfuric acid concentration to 72%, raise the temperature to 195° C., and stir at this temperature for 10 hours for isomerization. ...

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Abstract

The invention discloses a method for synthesizing dyestuff intermediate H acid by using naphthalene. In the method, the H acid is prepared by carrying out the steps of sulfonating with sulfonating agent sulfuric acid, nitrating with concentrated nitric acid, separating and neutralizing, reducing by catalytic hydrogenation, acid hydrolysis, and segregating on refined naphthalene. The H acid prepared by the method is suitable for various dyestuffs of active azo and the like, and can also be used for synthesizing medicaments. The synthesis method has the advantages of no tri-sulfonation, little waste acid amount, no alkali solution, less generated sulfur dioxide gas and inorganic salt, high yield, and reduced COD and secondary pollution of waste slag because of no iron cement generated by hydrogenation reduction.

Description

technical field [0001] The invention belongs to the field of organic chemical synthesis, and in particular relates to a new H acid synthesis process route and a synthesis method of 1,8-diaminonaphthalene-3,6-disulfonic acid sodium salt. Background technique [0002] At present, the preparation method of dye intermediate H acid [1-amino-8-naphthol-3,6-disulfonic acid monosodium salt] mainly adopts oleum staged sulfonation to obtain a trisulfonated mixture, and excessive Nitric acid nitration, after denitrification, directly neutralize with ammonia water, use iron powder to reduce nitro-TA acid to obtain amino-TA acid, acid analysis, filter cake beating for neutralization, add caustic soda for dehydration, heat up alkali fusion, add alkali melt to acid in acid Sulfur dioxide is released for recovery, H acid is precipitated, and H acid product is obtained by filtration. The above-mentioned method has a large amount of ammonium salts that need to be removed in the T acid isolat...

Claims

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Application Information

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IPC IPC(8): C07C309/50C07C303/32C07C309/47
Inventor 赵卫国苏金奇杨军芮国王国民
Owner 泰兴锦汇化工有限公司
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