Types of Distillation

Simple Distillation

• Purpose: Used for separating a liquid from a solution.
• Example: Separating pure water from seawater.

Equipment:

• Flask: Contains the solution or liquid mixture.
• Bung: Seals the flask to prevent gas escape.
• Thermometer: Measures the temperature inside the flask.
• Condenser:
  • Main pipe surrounded by a water jacket.
  • Cold water is fed in at the bottom and exits at the top.
• Beaker: Captures the pure liquid.
• Heating Device: Bunsen burner to heat the flask.

Process:

1. Heat the mixture to evaporate the desired liquid.
2. Vapor rises, moving into the condenser.
3. Cold water jacket cools vapor, condensing it into liquid.
4. Liquid collects in the beaker.
5. Example Outcome: Heating seawater results in pure distilled water, leaving behind salt.

Fractional Distillation

• Purpose: Used for separating mixtures of liquids with similar boiling points.

Equipment:

• Fractionating Column:
  • Filled with glass rods for high surface area.
  • Cooler at the top than the bottom.

Process:

1. Methanol Separation

   • Heat mixture to ~65°C for methanol evaporation.
   • Methanol vapors rise through the column, pass into the condenser, and collect as liquid.
   • Other liquids condense back into the flask.
   • Outcome: Pure methanol collected.

2. Ethanol Separation

   • Increase temperature to ~78°C for ethanol evaporation.
   • Pure ethanol is collected as liquid.

3. Propanol Separation

   • Remaining liquid assumed to be propanol.
   • Optionally, heat further to boil off propanol for purity assurance.

• Conclusion: Different distillation techniques are tailored to the liquid mixtures' properties, such as boiling points.

Additional Notes:

• Fractional distillation is essential when dealing with similar boiling points to achieve substance purity.
• Visualization aids (color coding) can assist in understanding separation processes.

End of Lecture Summary