How to purify acetic acid by distillation?

How to purify acetic acid by distillation?

Distillation is a widely used chemical separation technique for the purification of acetic acid. Acetic acid is an important organic compound, which is widely used in chemical, food and pharmaceutical fields. Acetic acid in industrial production usually contains impurities and moisture, and it is necessary to obtain high-purity products through purification methods. Because of its high efficiency and scalability, distillation has become one of the main methods for the purification of acetic acid. The steps, principles and precautions for purifying acetic acid by distillation are described in detail below.

1. Distillation Principle

The core principle of distillation is to use the different boiling points of substances to separate the mixture. Acetic acid has a boiling point of 118°C, while water has a boiling point of 100°C, and carbon and other impurities have higher boiling points. Separation and purification are achieved by heating the mixture to evaporate acetic acid prior to water and impurities, followed by cooling and condensation. This method is especially suitable for solutions with high acetic acid content, which can effectively remove water and other low boiling impurities.

2. distillation of acetic acid purification steps

1. Preparation of raw materials Before distillation, it is necessary to select a suitable acetic acid solution as the raw material. Generally, the use of higher purity acetic acid solution can reduce the interference of impurities and improve the purification efficiency. Distilled water is also one of the key raw materials, used to adjust the water content of the mixture.

2. Selection and Installation of Distillation Unit The distillation apparatus includes a still, a condenser, and a collector. The distillation kettle is used to heat the mixture, the condenser cools the evaporated acetic acid vapor into a liquid, and the collector is used to store the purified acetic acid. During the installation process, ensure that the device is well sealed to prevent steam leakage and impurities from mixing.

3. distillation operation

• The acetic acid solution and the appropriate proportion of distilled water were added to the still pot.
• Turn on the heating device and gradually increase the temperature to 110-120°C, so that the acetic acid begins to evaporate.
• Steam through the condenser cooling into the collector, collecting high purity acetic acid liquid.
• Repeat this process until the desired purity of acetic acid is collected.

1. 
   of impurity treatment During distillation, some impurities may remain in the still. After the distillation is completed, these residues need to be cleaned to ensure the efficiency and cleanliness of the next operation.

3. distillation method advantages and precautions

1. Advantage

• Distillation method is simple, low cost, suitable for large-scale production.
• Can effectively remove water and other low boiling point impurities, improve acetic acid purity.
• By controlling the distillation temperature, it is possible to further optimize product quality.

1. Precautions

• Safety issues: distillation process will produce harmful gases, need to ensure good ventilation conditions, and wear protective equipment.
• Temperature control: strictly control the heating temperature to avoid acetic acid due to overheating decomposition or by-products.
• Impurity treatment: regularly clean the distillation kettle in the residue to prevent impurities from affecting subsequent operations.
• Product quality: through testing equipment monitoring acetic acid purity and impurity content, to ensure compliance with industry standards.

4. DISTILLATION LIMITATION AND IMPROVEMENT

Although the distillation method performs well in purifying acetic acid, it still has some limitations. For example, close-boiling impurities may not be completely removed by distillation and need to be combined with other separation techniques, such as molecular distillation or chromatographic separation. Some by-products may be produced in the distillation process, which need further treatment to reduce environmental pollution.

5. summary

Distillation is an efficient and practical method for the purification of acetic acid, which is widely used in industrial production. The purity and yield of acetic acid can be significantly improved by reasonable selection of raw materials, optimization of distillation devices and strict control of operating conditions. For occasions where higher purity acetic acid is required, it can be combined with other separation technologies to further improve product quality. Therefore, distillation is still one of the important means of purifying acetic acid.