Heidolph Vacuum Switchbox - Manual (Page 58)

58
E
Copy vacuum gauge reading with arrow keys.
Complete calibration by hitting the "Set" key
INFORMATION ABOUT DISTILLATION SETTINGS
Using a rotary evaporator for thermal cracking of substances, some basic considerations should be
made to achieve the best results possible. Optimize settings as described below:
8. Rotary speed of evaporator flask
Raise distillation speed by raising rotational speed. This method cuts distillation time and protects
the substances handled.
9. Temperature difference between hot bath and vapor
This temperature difference should at lease be 20 K to achieve adequate distillation speed. If
acceptable by thermal stability of the substances handled, you even may raise temperature
difference.
Rule of thumb: double temperature to double distillation speed.
10. Temperature difference between vapor temperature and
coolant
This temperature difference should be no less than 20 K to guarantee adequate condensation.
With low temperature difference, effectiveness of solvent recovery drops. Choose an as high as
possible temperature difference in particular for high-boiling substances. .
11. Choose vacuum regulation mode and do respective
settings
11.1. "Manual" vacuum regulation mode
The "Manual" mode features the following parameters:
- separation of substances in a mix within physical limits
- no optional equipment needed
- manually select pressure when distilling mixes of substances
- high repetition accuracy
- requires detailed knowledge about thermal dynamic substance parameters
particularly for all standard processes
11.1.1. Settings in "Manual" regulation mode
- pressure "p" (Set Vac) and the hysteresis Δp (Set Δp) are set.
- choose pressure "p" as to locate boiling point of the substance to be distilled in the limits
defined by Chapters 9 and 10 (bath temperature and coolant temperature). To this end make