Acetonitrile water removal methods or equipment?
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The water content in acetonitrile is below 10% (by mass), and it is required that after treatment the acetonitrile content be at least 98%. I hope everyone here can help me
Direct distillation can fully meet the requirements
Acetonitrile forms azeotropes with water and many organic solvents, so the method of distillation alone for dehydration is usually not applicable. The normal boiling point of the acetonitrile-water binary azeotrope is 76°C, which is close to the normal boiling point of acetonitrile at 81.6°C; the azeotrophic composition contains 15% water by mass. For materials with an acetonitrile water content of less than 10% (by mass), desiccants such as calcium chloride can be used for dehydration, or molecular sieves can be employed for adsorption-based dehydration; the choice of specific process depends on the volume of material to be processed.
I heard that for the dehydration of industrial alcohol after it reaches its azeotrope point, lime is used for this purpose. It’s not sure whether using it on yours will cause deterioration due to excessive heat generation. This cost should be lower than that of calcium chloride and molecular sieves
Distillation is achieved using a distillation tower
This indicator is relatively easy to achieve; a regular distillation tower can be used to evaporate the azeotrope. It is necessary to consider a comprehensive comparison of the energy consumption of various methods in order to find the option that offers the best balance between energy consumption and equipment investment.
Reply to Building 7#: When the water content of acetonitrile in the feed is about 10% (by mass), an azeotropic distillation method is used; the vapor leaving the top of the tower contains mostly an azeotrope with a water content of around 15%, while only a very small amount of high-quality recovered acetonitrile can be obtained from the bottom of the tower. The recovery rate is extremely low. Furthermore, the water-containing azeotrope distilled from the top of the tower does not separate into layers upon condensation, making it difficult to further process.
Using azeotropic distillation, the recovery rate of high-quality acetonitrile product at the tower bottom is no more than 40%； More than 60% of the fed acetonitrile is distilled off at the top of the tower as an azeotrope (containing about 15 wt% water); it does not separate upon condensation, making further treatment difficult.
Do you mean a membrane is needed? I wonder what the lifespan of the membrane is?