Principle of Vacuum Distillation:
Distillation under reduced pressure (vacuum distillation) lowers the boiling points of the components in the mixture by reducing the ambient pressure, allowing distillation to occur at lower temperatures.
Methodology:
Setup: Similar to simple or fractional distillation but includes a vacuum pump to reduce the pressure in the apparatus.
Pressure Reduction: The pressure inside the distillation setup is reduced using the vacuum pump.
Heating: The mixture is heated to the required lower boiling point.
Vaporization and Condensation: Components vaporize at lower temperatures, pass through the condenser, and are collected.
Uses:
Distillation of heat-sensitive compounds that would decompose at higher temperatures.
Purification of high-boiling-point substances.
Used in the pharmaceutical, food, and chemical industries.
Merits:
Prevents thermal decomposition of sensitive compounds.
Reduces energy consumption by lowering the required distillation temperature.
Can be used to distil high-boiling-point materials.
Demerits:
Requires a vacuum system, increasing complexity and cost.
Not suitable for materials that cannot be vaporized under vacuum conditions.
Maintenance of vacuum equipment can be challenging.