Buchi Rotavapo R-220 SE User Manual download pdf (Page 69)

6 Operation

69 R-220 SE Operation Manual, Version F

6.2 Optimal distillation conditions

To achieve optimal distillation conditions, all distillation energy supplied by the heating bath must be

removed by the condenser. The physical cooling capacity of the condenser must not be exeeded in

order to avoid steam emission by overpressure inside the assembly!

NOTE:

• A temperature gradient of 20 °C between 'heating bath → vapor' and 'vapor → cooling medium'

is optimal for most distillation tasks. This rule can also be applied to other temperature ranges.

• During aeration (e.g. to suppress foam formation) the condensation height can decrease.

• Condensation over the complete condenser height is a sign for unsufﬁcient cooling capacity!

Adjust the distillation parameters (e.g. lower the cooling medium temperature) to stabilize the

condensation zone at approximately 2/3 to 3/4 during operation.

Cooling water source:

max. 20 °C

Vapor: 40 °C

Bath: 60 °C

Typical distillation parameter settings:

• Set the bath temperature to 60 °C.

• Use cooling water / medium with less than 20 °C.

• Allow cooling water / medium to ﬂow through the condenser at approximately 120 — 150 l/h.

• Adjust pressure parameter to reach a boiling point of ~40 °C for the used solvent. In most cases

it is necessary to apply a vacuum! Information about the corresponding pressure for common

solvents can be found in the following ‘Solvent table’.

Advantages associated with bath temperatures of 60 °C:

• Water can be used as heating medium (cost efﬁcient, good availability)

• Comparatively low comsumption of heating energy compared to higher bath temperatures

• Gentle product treatment at moderate temperature

• Shorter cooling-off time for evaporating ﬂask and heating medium

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Buchi Rotavapo R-220 SE User Manual Page 69