Various factors influence the distillation rate of a Rotavapor®. The following tips help you to improve the efficiency of your distillation process, to conserve energy and to reduce the environmental impact. The following charts show the distillation rate of acetone as a function of temperature, rotation speed and flask size, respectively.
Heating bath temperature:
A high heating performance (i.e. > 3.6 kW) only affects the distillation rate at high heating bath temperatures. For a difference of 20 °C or less between the vapor and bath temperature, distillation rates of a R-220 Pro, R-220 Pro High Performance or R-250 are identical.
To make use of the high heating power of a R-220 Pro High Performance or a R-250, set the bath temperature as high as possible
High rotation speed produces maximum turbulence inside the flask resulting in higher evaporation rates. However, for highly viscos samples, some foaming products, or spillage of heating media (e.g. when a drying flask is used), high rotation speed is not applicable.
Recommendation: The higher the rotation speed, the faster the distillation.
The larger the surface of the sample inside the flask, the higher the evaporation performance. On the other hand, large flasks are more difficult to handle and the sample is distributed over a larger area when evaporating to dryness.
Recommendation: The sample volume ideally fills 1/3 to ½ of the flask size.