Technological process of preparing sodium ethoxide by metal sodium method
There are two main methods for preparing sodium ethoxide:
One is alkali method, which generates sodium ethoxide and water from anhydrous ethanol and flake alkali,
Benzene ethanol water ternary azeotrope was removed by benzo distillation in the reaction system; The other is the metal sodium method, in which the metal sodium reacts with ethanol to generate sodium ethanol and hydrogen. Compared with alkali method, metal sodium method has the advantages of high product purity, simple process and no need to introduce flammable and carcinogenic benzene. The production process of metal sodium process uses and generates hazardous chemicals, and effective safety measures must be taken into account in the chemical design process.
Sodium ethoxide as strong alkaline catalyst and ethoxylating agent.
It is widely used in medicine and pesticide industry.
There are two types of industrial sodium ethoxide: liquid and solid. The liquid product is light yellow or brown, which is an ethanol solution containing about 17.5%~21% sodium ethoxide; Solid product is white or yellowish hygroscopic powder.
The content of sodium ethoxide is about 95%~97%. Sodium ethoxide is easy to decompose and deteriorate when encountering air or water,
Therefore, sodium ethoxide is best prepared and used on the spot.
Under the protection of nitrogen, metal sodium is put into the sodium ethoxide preparation kettle, and then excess ethanol is added by dropping. After the dropping is completed, the heat preservation reaction is continued until there is no bubble in the kettle. The product is transferred to the blending tank, sampled for analysis, and mixed to the required concentration, and finally transported to the next process.
The reaction principle is as follows：
2Na+2C2H5OH → 2C2H5ONa+ H2 ↑