# 5.6: Rotary Evaporation

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The preferred method for solvent removal in the laboratory is by use of a rotary evaporator (also known as a "rotovap"). A rotary evaporator is essentially a reduced pressure distillation: a solution in a round bottomed flask is placed in the water bath of the apparatus, and rotated while the system is partially evacuated (by a water aspirator or vacuum pump). The reduced pressure in the apparatus causes the solvent to boil at a lower temperature than normal, and rotating the flask increases the liquid's surface area and thus the rate of evaporation.

• 5.6A: Overview of Rotary Evaporation
It is very common for a desired compound to be dissolved in a solvent during regular manipulations in the laboratory. The preferred method for solvent removal in the laboratory is by use of a rotary evaporator, also known as a "rotovap". A rotary evaporator is essentially a reduced pressure distillation: a solution in a round bottomed flask is placed in the water bath of the apparatus , and rotated while the system is partially evacuated (by a water aspirator or vacuum pump).
• 5.6B: Step-by-Step Procedures for Rotary Evaporation
• 5.6C: Troubleshooting Rotary Evaporation
If the solvent fails to boil on the rotary evaporator even after one minute, consider whether a mistake may have been made. For example, it may be that you are trying to evaporate the aqueous layer from a separatory funnel step instead of the organic layer. Alternatively, the water bath may need to be heated to a higher temperature depending on the boiling point of the solvent.