25
BÜCHI
Rotavapor
R-200/205
5 Operation
5.6
Distilling
In this section, starting, optimising and ending a distillation are
shown on the basis of a checklist.
Apparatus is completely installed
• All electrical connections are correct
• All sealings have been correctly inserted
• All joints have been greased
• Evaporating flask is empty mounted
Evacuating apparatus in order to test tightness
(see 6.5, Functional test) max 3 mbar pressure increase/min.
Setting heating bath to desired value
Heating liquid has reached set temperature
Open cooling water
Allow cooling water to flow through the condenser at
approximately 40 – 50 l/h and not warmer than 20 °C.
Fill solution into the evaporating flask
• The solution can also be sucked in using vacuum
Start evacuation process
• Choose pressure in such a way that the boiling point of
the solvent is 40 °C (see Table, Chapter 5.7)
• Set rotation
• Use quick-action jack to sink flask into the bath
• After set vacuum has been reached, wait for 1- 2 minutes
to see whether distillation begins
• If distillation does not start, parameters must be optimised
again (Sink pressure gradually or increase bath
temperature)
In the optimum case, condenser is to be 2/3 to 3/4 burdened,
otherwise sink the pressure until this is the case (Not possible
for all distillation operations!).
