Method for continuous production of herbicide 2,4-dichlorophenoxyacetic acid

Abstract

The invention discloses a method for continuously producing herbicide 2,4-dichlorophenoxyacetic acid. According to the method, phenol and chlorine gas are used as raw materials; a continuous chlorination reaction is conducted through a micro-channel reactor to prepare 2,4-dichlorophenol, a condensation reaction is conducted through a tandem condensation reaction kettle to prepare 2,4-dichlorphenoxyacetic acid sodium salt, and then a continuous acidification reaction is conducted through a tandem acidification reaction kettle to prepare the 2,4-dichlorphenoxyacetic acid. Since continuous operation is realized in all the three reactions, the technological process is efficient, environmentally friendly, sustainable and suitable for industrial production; the method has the advantages that energy is saved, consumption is lowered, and emission of pollutants is reduced, and therefore safe and continuous industrial production is achieved.

Description

technical field [0001] The invention relates to a method for producing the herbicide 2,4-dichlorophenoxyacetic acid, in particular to a method for producing the herbicide 2,4-dichlorophenoxyacetic acid using a continuous process, which belongs to the preparation technology of the herbicide field. Background technique [0002] 2,4-Dichlorophenoxyacetic acid is a kind of widely used systemic conductive herbicide, which has phytohormone effect and herbicidal selection effect, and can stimulate the growth of plants at low concentration; Can destroy the plant metabolic process and kill the plant. At present, it is widely used in the control of weeds in wheat fields, corn, fruit trees, vegetables and other crops. [0003] The world's annual demand for 2,4-dichlorophenoxyacetic acid is over 50,000 tons. Major domestic manufacturers include Changzhou Yongtaifeng Chemical Co., Ltd., Shandong Weifang Runfeng Chemical Co., Ltd., etc. At present, there are mainly two kinds of prepara...

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Problems solved by technology

The intermittent production of 2,4-dichlorophenoxyacetic acid has many technical disadvantages, such as: (1), the chlorination section adopts the traditional batch method operation, which increases the human operation control factors and has a great impact on the quality of the chlorinated finished product (2), the production process control of the condensation workshop section is unstable, which increases the human operation factor, causing the fluctuation of the conversion rate of the condensation workshop section; (3), the variation of the sodium salt content due to the fluctuation of the conversion rate of the condensation workshop section has a great impact on the condensation waste water volume and The amount of circulating materials will have an impact; (4), the acidification section increases the human operation factor, causing the acidity of the wastewater in the acidification section to change, affecting the stability of the environmental protection section in the later stage

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