beerwiz
Hazard to Others
Posts: 128
Registered: 6-2-2014
Member Is Offline
Mood: No Mood
|
|
Rotary Evaporator vs Magnetic Stirrer for Distillations - which is superior?
I've tried doing simple distillations with a rotary evaporator and a magnetic stirrer, and to me it looks like the magnetic stirrer does a better job.
Am I wrong or are the two really the same? Both move the solvent around increasing the surface area.
And frankly based on my experience the rotavap takes longer to distill than the mag stirrer, but maybe my rotavap technique is flawed?
[Edited on 1-12-2016 by beerwiz]
|
|
|
DDTea
National Hazard
Posts: 940
Registered: 25-2-2003
Location: Freedomland
Member Is Offline
Mood: Degenerate
|
|
Rotovap is not for distillation per se. Rotovap is to remove solvent from a non-volatile component.
If you're trying to separate a mixture on the basis of the boiling points of its components, use a still with a stir bar/boiling chips.
"In the end the proud scientist or philosopher who cannot be bothered to make his thought accessible has no choice but to retire to the heights in
which dwell the Great Misunderstood and the Great Ignored, there to rail in Olympic superiority at the folly of mankind." - Reginald Kapp.
|
|
|
Dr.Bob
International Hazard
Posts: 2658
Registered: 26-1-2011
Location: USA - NC
Member Is Offline
Mood: No Mood
|
|
Using a rotovap allows lower BP temps, less likely to burn the residue. But if you are careful a stirred flask can boil solvent just fine. I use
simple distillations in some cases where I want more control or to keep a reaction warm or if the volumes are smaller. But if you need to
concentrate 12+ L of column fractions (Sadly that was my week), a good rotovap is great. The trick is to find the sweet spot of bath temp, vacuum
pressure, and rotation to get a nice constant evaporation without bumping.
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
