Sciencemadness Discussion Board

General Lab Glass Questions

Yttrium2 - 24-2-2023 at 18:52

Is 400mm Liebig condenser long enough? -- When is 500mm used?
-I was told to go with a 400mm Liebig.

Can allihn bulb condensers be packed with the glass packing -- for fractional distillation?

would a modified claisen adapter ( the kind that looks like a 3 neck) stand up to a 3 neck flask, i.e. under vacuum, or is it for some reason limited in this application?
It'd be ideal to consolidate
(Probably my last post)
EEEEek

[Edited on 2/25/2023 by Yttrium2]

s-l500.jpg - 41kB

[Edited on 2/25/2023 by Yttrium2]

j_sum1 - 24-2-2023 at 22:16

My liebig is 300 mm. The next one I buy will be 200mm.
If I need higher wattage cooling than the liebig then I go for a different design with greater surface area.
I know there are occasions where you wsnt a long straight condenser - even up to 600mm. But these are not applications that I am doing.
You can always apply less heat and distil a bit slower, so a big condenser is not always better anyway. A less aggressive distillation will give clearer fractions. And smaller surface reduces mechanucal losses.

I would think packing a straight column will be easier than an ahlinn. But whatever.

The adapter you show may make a reasonable substitute for a 3 neck flask. But really, get the adapters you need for the projects you are doing. Watch a bunch of chemplayer vids. It is amazing what he accomplished with just a beaker and some vacuum filtration.