How to Use a Rotary Evaporator (Rotavap)

[ Music ]>>The rotary evaporator
or rotavap is used to remove organic solvents
from solutions that are in a round bottom flask. Make sure before
you use the rotavap that your round bottom
flask is less than half full and that the vacuum pump
is on [pump running]. Now we are turning the pump
off for video purposes. The rotavap has three main
controls; rotation control knob, an up and down switch,
and the vacuum vent valve. The valve opens the whole system through the atmosphere
when is pointing up. There is an open valve here
that connects to the atmosphere. When you point the valve down,
the whole system is connected through these vacuum
tube to the vacuum pump. So the whole system
is on the vacuum. So to put your flask through
the rotavap you couple the glass joint and you secure
it with a keck clip. The keck clip has two sides, a
small side and the larger side. You want to straddle the joint and the small side
goes on the small neck. The larger side goes
on the large neck. Then you connect the
system to the vacuum, turn it down pointing
towards the vacuum hose. Immediately start the rotation and for a small flask the
rotation can be fairly brisk, half to three-quarters
of the speed, and then you lower your
flask in the water bath. [ Music ] [ Pump Running ] When the rotavap is
working correctly, you should see your
solvent dripping down the cold finger
into the reservoir. [ Pump Running ] When there’s no liquid left
in your round bottom flask, and you can stop the rotation to
check that, you lift your flask out of the water bath, you
vent the system and you want to hear it hissing
[hissing sound]. Then you remove the keck
clip and remove your flask. You can leave the rotavap
as it is for the next user. After you have removed all the
solvent from your solution, the round bottom flask
may look empty, it’s not. If you have a liquid compound,
you might just have a drop in there, which is spread
around the whole wall, so you don’t really see
it even if it is in there. What you collect here is
the solvent that is waste. [ Music ]

4 thoughts on “How to Use a Rotary Evaporator (Rotavap)

  1. Once I forgot to turn vaccum off after I used it and the pressure stole my product. It was a little embarassing, but it must have looked kinda funny to my colleagues 😀

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