flakten
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Vacuum Desiccator vs Rotary Evaporator
This question will probably seem foolish to you experienced chemists, that's why I posted it in "Beginnings".
The question is simple: What are the different advantages ad disadvantages of a rotovap and a vacuum desiccator?
Temperature control? But with a bit of craftsmanship you can control the temperature in the desiccator too.
So why do some chemists spend £1-2.000 on a rotovap?
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Sulaiman
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I believe that when a rotovap is used, the solvent is condensed and recovered,
A vacuum dessicator removes but can not recover the solvent due to the vacuum.
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flakten
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So solvent recovery would be the only advantage?
But I use a vacuum desiccator an I have solvent trap so that the solvents don't damage my precious pumps.
But either way the solvent can only be reused for identical experiments since it will now contain trace elements of chemicals, products and side
reactions.
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NitreRat
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Rotovaps are capable of removing much more solvent than most vacuum desiccators are capable of. Vacuum desiccators are normally just used for drying
solids which still contain small amounts of solvent and are too temperature sensitive for lab ovens. Rotovaps also have the advantage (over normal
vacuum distillation) that they rotate, which greatly increases the rate of solvent evaporation. More expensive models also have many adjustable
settings tailored for specific solvents so you can safely leave your experiment for long durations of time. In a professional lab you can't afford to
be constantly carefully controlling your vacuum desiccator's temperature. Another advantage I can think of is that they fit ground-glass jointed
glassware so you can use the same flask used in the reaction, reducing transfer loss.
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beerwiz
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Rotavaps remove the solvent much faster than regular distillation or a vacuum dessicator. But I've found that if you do a regular distillation but use
a magnetic stirrer, the speed of the vacuum distillation is comparable to the rotavap.
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