Design of A Rotary Evaporator
The main components of a rotary evaporator are:
- A motor unit that rotates the evaporation flask.
- . A heated fluid bath (generally water) to heat the sample.
- A condenser or 2-3 condensers with either a coil passing coolant, or a "cold finger" into which coolant mixtures such as dry ice and acetone are placed.
- A receiving flask at the bottom of the condenser, to catch the distilling solvent after it re-condenses.
- A mechanical or motorized mechanism to quickly lift the evaporation flask from the heating bath.
The vacuum system used with rotary evaporators can be as simple as a water aspirator with a trap immersed in a cold bath (for non-toxic solvents), or as complex as a regulated mechanical vacuum pump with refrigerated trap. Glassware used in the vapor stream and condenser can be simple or complex, depending upon the goals of the evaporation, and any propensities the dissolved compounds might give to the mixture (e.g., to foam or "bump"). Modern equipment often has features such as digital control of vacuum, digital display of temperature and rotational speed, and vapor temperature sensing.