Process for continuously producing chloroacetic acid through acetic anhydride catalytic method

Abstract

The invention discloses a process for continuously producing chloroacetic acid through an acetic anhydride catalytic method. The production process comprises the steps: using acetic acid and chlorineas raw materials, using acetic anhydride as a catalyst, introducing chlorine for a reaction in a first-stage chlorination main kettle, conveying a reaction liquid to a second-stage chlorination main kettle through a pump, introducing chlorine for a reaction continuously in the second-stage chlorination main kettle, conveying the reaction liquid in the second-stage chlorination main kettle to a hydrolysis kettle through a pump, adding an appropriate amount of water to the hydrolysis kettle, removing unreacted intermediate products through a hydrolysis reaction, conveying the hydrolyzed reactionliquid to a rectification column through a pump, introducing steam into a reboiler of the rectification column for material heating, and separating the light component acetic acid and the heavy component chloroacetic acid from the reaction liquid; and condensing liquid foam in the reaction gas of the chlorination reaction kettles through a first-stage condenser and a second-stage condenser, returning the condensed liquid foam to the chlorination reaction kettles through reflux pipes separately, and sending the reaction gas condensed by the condensers to an exhaust gas treatment process for further treatment.

Description

technical field [0001] The invention relates to the production technology of chloroacetic acid, in particular to a new process of the catalyzed continuous method of chloroacetic acetic anhydride. Background technique [0002] Using acetic acid and chlorine as raw materials to produce chloroacetic acid, the chemical reaction formula is as follows: [0003] [0004] In the process of producing chloroacetic acid with glacial acetic acid and chlorine as raw materials, various production processes are derived according to the catalyst used in the reaction and whether the process is continuous. Among them, according to the catalyst used, it is divided into two types: sulfur catalysis method and acetic anhydride catalysis method, and according to whether the production process is continuous or not, it is divided into two types: batch method and continuous method. At present, the production process of chloroacetic acid in the domestic chloroacetic acid industry mainly includes t...

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Problems solved by technology

[0007] 2. Due to the use of sulfur as a catalyst, the chloroacetic acid product contains elemental sulfur and its compounds, resulting in many impurities in the product chloroacetic acid, which affects downstream use

[0008] 3. The by-product hydrochloric acid contains elemental sulfur, sulfuric acid, sulfurous acid and other compounds, resulting in poor quality of by-product hydrochloric acid, and the purification is difficult and costly, and it is difficult to use downstream, and the environmental protection hazard is relatively large

[0009] 4. The device occupies a large area and has a low degree of automation

[0010] Some chloroacetic acid plants in China are produced by the acetic anhydride catalytic batch method, and the quality of the main product chloroacetic acid and by-product hydrochloric acid has improved, but due to the single-pot batch method, the device occupies a large area and has a low degree of automation

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