Under vacuum conditions, the weight of the atmosphere places less of a force on the liquid surface aka no vapor pressure. Compounds evaporate more easily and at lower boiling points because they are facing reduced resistance. These conditions also reduce condensation point, requiring more cooling & turbulence for collection. Also, due to the reduced boiling points, compounds are more likely to distill together, making fractional distillation more difficult. The primary advantage is the ability to perform low temperature distillations, protecting sensitive compounds from damage or loss. And, secondarily, operating under vacuum will significantly increase your solvent recovery and oil distillation rates.

The fractional precision of distillation often comes down to the design of the columns. They are a critical part of controlling these processes and setting the limitations for flow and separation efficiency. This, perhaps, increases the given batch time or retention on the wiper, but overall process time due to prep & post-processing is reduced or eliminated. This is thanks to the precision, high-purity distillation achieved in one pass, alongside high yields, from even significantly impure crude oils.