Buchi Rotavapor R-100 - Adjusting Distillation Conditions

6 | Operation BÜCHI Labortechnik AG
34/60 Operation Manual Rotavapor® R-100
6.2.2 Adjusting distillation conditions
To obtain optimum distillation conditions, the energy absorbed by the solvent from the
heating bath must be removed again in the condenser. To achieve that, the following
settings are recommended:
Δ 20 °C
20 °C
40 °C
60 °C
Δ 20 °C
1
1
2
3
1 Coolant temperature: 20 °C
2 Vapor temperature: 40 °C
3 Heating bath temperature: 60 °C
The temperature difference between heating bath and evaporating flask and between
evaporating flask and condenser should be 20 °C in each case.
The pressure in the evaporating flask should be set so that the boiling point of the sol-
vent is around 40°C (see Chapter10.1 "Solvent table", page47).
The flow rate of the coolant depends on the type of coolant used and the capacity of
the cooler but should be at least 40 – 50 L/h.
Those settings offer the following advantages:
 The evaporating flask can be replaced without the risk of skin burns.
 The evaporation rate of the water in the heating bath is low.
 The energy of the heating bath is efficiently utilized.
To achieve optimum distillation, all devices in the system should be matched to one
another. Therefore, we recommend that the Rotavapor® R-100 is used together with
the BUCHI Vacuum Pump V-100 and the BUCHI Recirculating Chiller F-105 (see
Chapter3.2.4 "Typical application", page14). That will enable achievement of a sta-
ble vacuum and stable cooling, and thus a more efficient distillation process.