A rotary evaporator is a device commonly used in chemical laboratories for the efficient and gentle removal of the volatile solvents from samples by evaporation. They are found in almost every organic laboratory. The rotation flask rotates and shapes a thin film in negative pressure condition by heating; it evaporates; and then the vapor is condensed, liquefied, and recollected for separation.
A typical thin film evaporator has a water bath that can be heated in either a metal container or crystallization dish. This keeps the solvent from freezing during the evaporation process. The solvent is removed under vacuum, is trapped by a condenser, and is collected for easy reuse or disposal.