Manufacturing Method of Chloroacetic Acid (Sulfur Method)
Chloroacetic acid is an important organic chemical raw material, which is widely used in pesticides, pharmaceuticals, dyes, plastics and other fields. There are various manufacturing methods for chloroacetic acid, among which sulfur method is a common production method. This article will introduce the manufacturing method of chloroacetic acid (sulfur method) in detail.
I. Raw materials and equipment
1. Raw materials: acetic acid, chlorine, sulfur, sodium hydroxide.
2. Equipment: reaction kettle, condenser, storage tank, stirrer, pump, thermometer, manometer and so on.
2. Manufacturing steps
1. Add acetic acid into the reactor, turn on the stirrer and keep a certain stirring speed.
2. Pass in chlorine gas and add sulfur at the same time, so that chlorine gas and sulfur react in acetic acid to form chloroacetic acid and sulfuric acid.
3. Control the reaction temperature, generally in the range of 30-50 ℃, to avoid too high a temperature leading to the generation of by-products.
4. Continuously monitor the pH of the reaction solution during the reaction, when the pH drops to a certain value, the reaction is basically complete.
5. Add sodium hydroxide solution to the reaction solution and adjust the pH to neutral or slightly acidic so that chloroacetic acid precipitates as a salt.
6. Filter, wash and dry the precipitate to obtain chloroacetic acid product.
3. Precautions
1. Strictly control the reaction temperature and pH value to avoid the generation of by-products and the decrease of product quality.
2. Keep the equipment well sealed during operation to prevent chlorine gas from leaking and polluting the environment.
3. Operators should wear protective gears to avoid contact with toxic and hazardous substances.
4. Waste should be properly disposed of to avoid harming the environment and ecology.
4. Product quality control
1. Conduct quality inspection on the products, including purity, acidity, chlorine content and other indicators.
2. Monitor the production process to ensure stable and reliable product quality.
3. Dispose of unqualified products to prevent them from entering the market.
In conclusion, the manufacturing method of chloroacetic acid (sulfur method) requires strict control of reaction conditions and operation process to ensure product quality and production safety. Meanwhile, waste treatment and environmental protection should be strengthened to realize green production.
