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Method for preparing sodium salt DNS acid from NTS

A sodium and sodium hydroxide technology, applied in 4 fields, can solve the problems of increasing power and heating steam consumption, uneven distribution of gas and liquid, formation of by-products, etc., to improve mass transfer conditions, reduce energy consumption, and reduce consumption. Effect

Inactive Publication Date: 2004-03-10
TIANJIN UNIV
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

This greatly increases the consumption of power and heating steam
In addition, due to the uneven distribution of gas and liquid in the kettle, by-products are formed, the yield is reduced, and even the phenomenon of "red pot" appears

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0009] Add 2g of activated carbon particles with a particle size of 20μm and 730mL of NaOH solution with a concentration of 0.9~1.0M into a 4L oxidation kettle with a flow rate of 0.04m 3 / h of air. Then, 100 mL of NTS solution with a concentration of 800 g / L was dropped into the reaction kettle within 40 minutes, and 80 mL of industrial-grade NaOH solution with a concentration of 11.40 mol / L was added dropwise to maintain the alkali concentration of the system unchanged. During this process, the temperature of the reaction system was maintained at 52-54°C.

[0010] In the first 2h of the reaction, the reaction temperature was maintained at 56-58°C, and the base value of the system was adjusted to 1.8M with 90mL NaOH solution.

[0011] In the second 2h of the reaction, the temperature was raised to 62-64°C, water was added to adjust the base value of the system to 0.9M, and 2g of activated carbon was added at the same time. Then, the temperature is increased to 69-71°C within 2h, ...

Embodiment 2

[0014] Follow the steps in Example 1, but the added activated carbon is 2.4 g, the particle size is 40 μm, and the reaction yield is 87.7%.

Embodiment 3

[0016] Follow the steps in Example 1, but the added activated carbon is 2.4 g, the particle size is 20 μm, and the reaction yield is 88.4%.

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Abstract

A process for preparing the sodium salt of 4,4'-dinitrobistyrene-2,2'-disulfonic acid (DNS) from NTS includes preparing the sodium hydroxide solution of NTS, adding inertial solid particles, introducing air or oxygen, regulating pH value, oxidizing condensation reaction at a certain temp, acidifying, salint-crystallizing and filter. Its advantages are high output rate, and low energy consumption.

Description

Technical field [0001] The invention relates to a method for synthesizing nitrostilbene sulfonic acid, in particular to a method for synthesizing 4,4'-dinitrostilbene-2,2'-disulfonic acid (DNS). Background technique [0002] DNS is the synthetic raw material of dye intermediate 4,4'-diaminostilbene-2,2'-disulfonic acid (DSD acid). There are more than one hundred kinds of fluorescent brighteners based on DSD acid, and five reactive dyes. More than ten kinds, more than 70 kinds of direct dyes, dyes synthesized with DSD acid as a substitute for benzidine dyes, due to their non-toxicity and no accumulation in the human body, they have received extensive attention in recent years and have developed rapidly. [0003] Industrially, DNS and its salts are usually prepared by oxidative condensation of p-nitrotoluene o-sulfonic acid (NTS) in a strong alkaline medium. The oxidant (usually accompanied by a catalyst) can be oxygen or oxygen-enriched air. , Sodium hypochlorite or chlorine, etc....

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C07C303/22C07C309/40
Inventor 赵永江张凤宝张国亮王淑兰戈建华
Owner TIANJIN UNIV
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