Vacuum distillation is the process of separating a mixture of liquids by evaporation and condensation. This is normally performed by heating the liquid until boiling occurs, indicating that the vapor pressure of the liquid has exceeded the ambient pressure.

However, heat can damage the structure of temperature-sensitive substances. In such cases, vacuum distillation is preferred, in which a vacuum pump is used to significantly reduce the boiling point of the liquid. A chemical duty diaphragm pump is recommended for this method.