Sciencemadness Discussion Board

problem with rotovap

soma - 24-12-2013 at 12:44

We've got a buchler rotovap. There's a problem with the flange -- it fills up with distillate and at the end I have to drain it but the solvent is somewhat hard to drain and leaks out the boil end and under the adapter on the distill end.

I've attached photos of the rotovap and flange.

Suggestions welcome.



Paddywhacker - 24-12-2013 at 14:26

Use recirculated antifreeze from a nearby freezer as your condenser cooling liquid. Keep your distillate receiver chilled.

soma - 24-12-2013 at 14:38

The flange connects to the condenser and fills up before anything reaches the condenser. If there was some kind of heating mantle that could fit over the flange, that might solve it. This has to be a common problem -- at least with this type of rotovap. I'm wondering how others handle it. If the rotovap was able to tip further over I could just pour the liquid out from the top.

[Edited on 24-12-2013 by soma]

chemrox - 24-12-2013 at 16:00

I do a lot of Buchi repair and used evap sales. Can you PM me with a photo? Or post one showing exactly what's going on? Is the condenser collecting solvent? Is the solvent going into the collection flask? Show me what the setup looks like when it's in use. There may be something really simple with angle adjustments going on or you may need a gasket change. BTW I have a Buchler minus the glassware I could let you have cheap or trade.

killer_lapin - 26-12-2013 at 06:41

If you vacuum is not strong enought the vapor may condense before reaching the condenser causing liquid to accumulate in the mantle. It is a common problem with rotovap. A heating mantle may be a good alternative if you dont want to get a new pump.

soma - 27-12-2013 at 22:47

I'm using it without a vacuum for this (although I have one). It's an easy way to prevent bumping. It's not real easy to get dry ice or liquid nitrogen.

[Edited on 28-12-2013 by soma]

soma - 27-12-2013 at 23:16

Quote: Originally posted by chemrox  
I do a lot of Buchi repair and used evap sales. Can you PM me with a photo? Or post one showing exactly what's going on? Is the condenser collecting solvent? Is the solvent going into the collection flask? Show me what the setup looks like when it's in use. There may be something really simple with angle adjustments going on or you may need a gasket change. BTW I have a Buchler minus the glassware I could let you have cheap or trade.


I've drawn an arrow to the area where the distillate collects. BTW, the large white nut holding the flange on the distillation side (to the right of the arrow) was an ad-lib. The rotovap didn't come with one and I couldn't find anyone that had one. As it turned out, the cap on a 5 gallon plastic container ended up being almost exactly the right size. Could use the original tho if you have one.