Preparation method for continuously synthesizing indigotin

A technology for synthesizing indigo in a liquid state, applied in the direction of bis-indole indigo indigo dyes, etc., can solve the problems of large consumption, high price, secondary pollution, etc.

Inactive Publication Date: 2009-09-16
JIANGSU TAIFENG CHEM
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

These alkalis can also be partially recovered, but require large consumption and high price of potassium hydroxide resources
A small amount of non-reusable mixed alkali residue after repeated application will bring secondary pollution

Method used

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Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0008] React liquid metal sodium with ammonia gas in the tower for 3 hours at 300-380°C to generate sodium amide, add it to the molten anhydrous alkali according to a certain proportion, stir and mix well, and then continuously add the mixed In the material reactor, use the above-mentioned alkali as a solvent and sodium amide as a condensation agent, continuously add aniline acetate, at a temperature of 180°C to 250°C, and a pressure of 0.1-0.5Mpa, aniline acetate is cyclized Hydroxyindoxyl salt is continuously put into the oxidation tank, and indigo is obtained through tower circulation oxidation. The base is potassium hydroxide, sodium hydroxide or a mixture of both.

[0009] In the above preparation process, 9000 kg of potassium anilinoacetic acid sodium salt, 4000 kg of potassium hydroxide and sodium hydroxide mixed alkali, and 2500 kg of sodium metal were used for 2.5 hours to react to obtain 5570 kg of indigo with a yield of 86%.

[0010] In the above preparation proces...

Embodiment 2

[0012] Using 9000 kg of potassium anilinoacetic acid sodium salt, 4000 kg of potassium hydroxide, and 2500 kg of sodium metal, reacted for 2.5 hours to obtain 5578 kg of indigo with a yield of 85%. All the other processes are the same as in Example 1.

Embodiment 3

[0014] Using 9000 kg of potassium anilinoacetic acid sodium salt, 4000 kg of sodium hydroxide, and 2500 kg of metallic sodium, reacted for 2.5 hours to obtain 5381 kg of indigo with a yield of 82%. All the other processes are the same as in Example 1.

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PUM

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Abstract

The invention discloses a preparation method for continuously synthesizing indigotin, which comprises the steps that: liquid sodium metal reacts with ammonia gas at a certain temperature to produce sodium amide; the sodium amide is added to molten anhydrous alkali in a certain proportion, and then the mixture of the sodium amide and the anhydrous alkali is continuously added to a mixing reactor; anilino acetate is continuously added to the mixing reactor taking the anhydrous alkali as a solvent and the sodium amide as a condensing agent; and the anilino acetate is cyclized into hydroxyindole phenolate at certain temperature and pressure, and then the hydroxyindole phenolate is continuously oxidized to produce the indigotin. The alkali is potassium hydroxide, sodium hydroxide or a mixture of the potassium hydroxide and the sodium hydroxide. The method has the advantages of improving the reaction yield and the product quality, shortening the reaction period, reducing the generation of pollutants, reducing the equipment investment and the employee labor intensity, improving the working environment, and greatly reducing the energy consumption and the production cost.

Description

technical field [0001] The invention relates to a preparation method for continuously synthesizing indigo Background technique [0002] The traditional indigo production all adopts kettle reaction and batch operation. However, gap production has problems such as long reaction cycle, low production capacity per unit time, high equipment investment, large floor area, high labor intensity, many waste discharge points, large pollutant discharge, high material consumption and energy consumption. [0003] The traditional production method uses a mixed alkali composed of potassium hydroxide and sodium hydroxide as the solvent for the indigo synthesis reaction, although the sodium amide and phenylaminoacetate in the reaction can be well dissolved in this mixed alkali solvent , After the reaction, the product indigo can be separated from the aqueous alkali solution. These bases can also be partially recovered, but the resource of potassium hydroxide, which consumes a lot and is exp...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): C09B7/02
Inventor 张正西刘国平吴德生赵忠民栾敏红
Owner JIANGSU TAIFENG CHEM
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