Preparation method for synthesizing indigotin through continuous oxidation

Abstract

The invention discloses a preparation method for synthesizing indigotin through continuous oxidation, which comprises the following steps: introducing ammonia gas into liquid sodium metal, and performing reaction in an ammonia-sodium synthesizing tower to generate sodium amide; adding the sodium amide into alkali according to certain proportion, and adding the mixture into a material-mixing reactor continuously or at intervals; at certain temperature and pressure, using the alkali as a solvent and the sodium amide as a condensating agent, and adding anilino-acetate continuously to cyclize the anilino-acetate into hydroxy indole phenolate; discharging the materials continuously and diluting the materials with water, and then adding 3 to 20 percent w/w of indole phenolate solution into an oxidation reaction tower continuously from the upper part of the tower; introducing air into the tower from the lower part of the tower at a temperature of between 60 and 80 DEG C; after the continuous cyclic oxidations by an oxidation tower and oxidation reaction devices, sending the materials oxidized to the end point to post-processing from the bottom of the tower; and obtaining the indigotin through filtering, washing and drying. The preparation method improves the reaction yield and the product quality, shortens the reaction period, and greatly reduces the energy consumption.

Description

technical field [0001] The invention relates to a preparation method for continuous oxidation synthesis of 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 is to dilute the synthesized indoxyl salt with water, and then directly pass air into the kettle for oxidation. The utilization rate of oxygen is low, the oxidation time is long, and a large number of side reactions are generated, which affects the quality of the finished indigo. A large amount of foam is generated during the oxidation process, and a large amount of defoaming agent must be used to defoam, and the production cost is high....

AI Technical Summary

Problems solved by technology

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, etc.

[0003] The traditional production method is to dilute the synthesized indoxyl salt with water, a...