Drying using drying agents

• Drying involves using a drying agent to remove water from a liquid organic product. Water is considered an impurity in this instance, so needs to be removed.
• One major feature of a drying agent is that it must not react with the organic liquid.
• Typical drying agent are anhydrous metal salts (e.g. calcium/magnesium/sodium sulfate). When these compounds come into contact with water, they form hydrated salts, so absorb water from the organic liquid.
• In the first stage of drying, the drying agent is added to the organic liquid, then the mixture is shaken and left for some time. This agent should become crystalline after absorbing water, and if more agent is added and it remains powdery, the liquid is now dry.
• After the process of drying, the drying agent can be removed either via decantation (pouring the organic liquid off the solid drying agent) or filtration.