Process for preparing indigo and its intermediate

A technology based on indigo and aniline, applied in the field of indigo preparation, can solve problems such as cost pollution, achieve the effects of solving governance problems, reducing labor intensity, and improving the working environment

Inactive Publication Date: 2005-03-02
JIANGSU TAIFENG CHEM +1
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

[0004] In order to solve the problem of cost and pollution, the present invention provides a method of preparing potassium sodium anilinoacetate by using anilinoacetonitrile as the main raw material, and using this as an intermediate to prepare the anhydrous mixed alkali of liquid ammonia and potassium sodium for recycling. indigo method

Method used

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Examples

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Embodiment Construction

[0010] The preparation method of a kind of indigo of the present invention is to add quantitative metal sodium into the reaction tank, after heating up and melting, at the specified temperature, feed fresh or recycled liquid ammonia to react to produce sodium amide, and then add it to the pre-filled fresh Or in the retort of the anhydrous potassium sodium mixed alkali (NaOH, KOH) that reclaims, under certain temperature, with fresh or reclaim alkali as solvent, sodium amide is made condensing agent, gap adds a batch of potassium anilinoacetic acid sodium salt, Indoxylate potassium (sodium) is synthesized by cyclizing potassium anilinoacetic acid sodium salt under high temperature and high pressure, and then oxidized, press-filtered and dried to obtain indigo.

[0011] The preparation of the intermediate potassium anilinoacetic acid sodium salt is to add anilinoacetonitrile to the mother liquor whose temperature is lower than 65°C, after it dissolves, cool down to within 50°C, a...

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Abstract

An indigo is prepared from anilinoacetonitrile as main raw material, anhydrous K-Na alkali mixture as solvent, and aminosodium as condensating agent through adding potassium sodium (or potassium) anilinoacetate, cyclyzing the potassium sodium anilinoacetate to become the indolol potassium (or sodium) at high temp and pressure, oxidizing, press filtering and drying. Said potassium sodium (or potassium) anilinoacetate as intermediate is prepared through proportionally mixing anilinoacetonitrile with the liquid K-Na alkali mixture or liquid K alkali.

Description

[0001] Field [0002] The invention relates to a method for preparing indigo with anilinoacetonitrile as the main raw material. Background technique [0003] In the traditional indigo synthesis, industrial product liquid ammonia is used to react with metal sodium to produce condensing agent sodium amide, which is used for alkali fusion, and the mixed alkali used for alkali fusion is the solid industrial product sodium hydroxide and potassium hydroxide purchased in the market, according to 1: The ratio of 1.5 is melted and used as a solvent for alkali fusion, and the potassium aniline acetate is cyclized by alkali fusion to generate potassium indoxylate, and then oxidized, filtered, and dried to obtain indigo products. The synthesis of the intermediate aniline and chloroacetic acid potassium salt is made of aniline and chloroacetic acid as raw materials: ferrous sulfate, liquid caustic soda, aniline and chloroacetic acid are reacted in a synthesis tank to prepare aniline and ch...

Claims

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): C09B7/00
Inventor 罗必奎毛卫平张文达周红灯郑长春赵中明尹应武张荣生侯跃灯
Owner JIANGSU TAIFENG CHEM
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