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Method for preparing 4, 4'-diamido stilbene-2, 2'-disulfonic acid

A technology of diaminostilbene and dinitrostilbene, which is applied in the field of preparing DSD acid, can solve problems such as environmental pollution and reduce production costs, and achieve the effects of reducing environmental pollution, reducing production costs, and mild reaction conditions

Inactive Publication Date: 2013-07-10
HEBEI HUA CHEM DYE CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0005] The purpose of this invention is to provide a kind of method that utilizes iron oxide as catalyst, ferrous salt as reducing agent to prepare 4,4'-diaminostilbene-2,2'-disulfonic acid, reduces production cost, solves the problem of Environmental pollution caused by iron sludge produced by reduction of iron powder

Method used

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Examples

Experimental program
Comparison scheme
Effect test

example 1

[0017] First weigh 9g of 68% DNS, add 200mL water to dissolve, add 0.5gFe 3 o 4 , and the temperature of the solution was raised to 30°C, and 90mL of 3mol / L FeCl was added within 60min under constant stirring 2 Solution, while using 30% NaOH to maintain the pH of the reaction at about 7, after adding ferrous iron, continue to stir for 5 minutes. Then the pH of the reaction solution was adjusted to about 9.5, 0.2 g of sodium hydrosulfite was added and filtered, and the filter cake was washed and dried to obtain 23.36 g of miscible iron oxide. After the filtrate was heated to 80°C, the pH was adjusted between 1 and 2 with 98% concentrated sulfuric acid, and the solution was filtered with suction to finally obtain 10.35 g of DSD acid wet product.

example 2

[0019] First weigh 9g of 68% DNS, add 200mL water to dissolve, add 0.5gFe 3 o 4 , and the temperature of the solution was raised to 50°C, and 90mL of 3mol / L FeCl was added within 60min under constant stirring 2 Solution, while using 30% NaOH to maintain the pH of the reaction at about 7, after adding ferrous iron, continue to stir for 5 minutes. Then the pH of the reaction solution was adjusted to about 9.5, and 0.2 g of sodium hydrosulfite was added and then filtered. The filter cake was washed and dried to obtain 21.82 g of pure-phase iron oxide black. After the filtrate was heated to 80°C, the pH was adjusted between 1 and 2 with 98% concentrated sulfuric acid, and the solution was suction-filtered to finally obtain 11.78 g of DSD acid wet product.

example 3

[0021] First weigh 9g of 68% DNS, add 200mL water to dissolve, add 0.5gFe 3 o 4 , and the temperature of the solution was raised to 70°C, and 90mL of 3mol / L FeCl was added within 60min under constant stirring 2 Solution, while using 30% NaOH to maintain the pH of the reaction at about 7, after adding ferrous iron, continue to stir for 5 minutes. Then the pH of the reaction solution was adjusted to about 9.5, and 0.2 g of sodium hydrosulfite was added and then filtered. The filter cake was washed and dried to obtain 22.24 g of iron black. After the filtrate was heated to 80°C, the pH was adjusted between 1 and 2 with 98% concentrated sulfuric acid, and the solution was filtered with suction to finally obtain 9.80 g of DSD acid wet product.

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Abstract

The invention discloses a method for preparing 4, 4'-diamido stilbene-2, 2'-disulfonic acid. The method comprises the following steps of: using the 4, 4'-dinitro stilbene-2, 2'-disulfonic acid (DNS) as a raw material, using water as a solvent, in the presence of an iron oxide catalyst, reducing with ferrous iron, wherein the reaction conditions are as follows: the mass concentration of the raw material in the water is 1%-15%, the reduction temperature is 25-80 DEG C, the pH value is 6.0-9.0, and the dosage of the catalyst is 0.5-5.0g / l. In the method, the cheap ferrite or ferrous pickling waste liquor as the reducing agent, the ferrous iron is oxidized and further hydrolyzed to generate iron oxide, and the iron oxide can be sold as a product, so that the method is environment-friendly. In the method, the technology is simple, the reaction conditions are mild, the catalyst is high in activity and strong in selectivity, and the production cost is lowered.

Description

[0001] technical field [0002] The invention relates to a method for preparing DSD acid, which belongs to the technical field of organic synthesis in the chemical industry. Background technique [0003] 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD) is an important intermediate in the field of fine chemicals, widely used in the manufacture of optical brighteners, dyes, reactive dyes and other fields. The synthesis of DSD acid is usually achieved by non-catalytic reduction of metal powders (such as Fe powder), transition metal-catalyzed or noble metal-catalyzed hydrogenation reduction of aromatic nitro compounds. Although the non-catalytic Fe powder reduction process is relatively mature, it will produce iron sludge that can pollute the environment (Gao Ge et al., Modern Chemicals, 2011, 31, (1):57-60); transition metal catalytic hydrogenation is a clean production process , but the reduction selectivity is relatively poor, and it is easy to produce deep reduction (Chem. R...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C309/46C07C303/02
Inventor 魏雨谷占冬段卫东张中领宫占胜陈治淮
Owner HEBEI HUA CHEM DYE CHEM
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