Sciencemadness Discussion Board

Distillation flask

liquidlightning - 13-5-2012 at 19:09

How would one use a distillation flask such as this: ?

Does the side arm act as an air cooled condenser, or do you need to attach a condenser? I'm assuming a rubber stopper for the top.

bbartlog - 14-5-2012 at 06:28

I would assume that the side arm is for applying vacuum. But in the case of the flask you link to, I'm really not sure; it has neither a ground glass joint on top nor a barbed fitting on the sidearm for attaching a hose to. And both neck and sidearm look excessively long. I don't like the design.

(edit): above comments assume that it's a receiver, which I suppose it may not be.

[Edited on 14-5-2012 by bbartlog]

fledarmus - 14-5-2012 at 06:40

That appears to be an old-style short path distillation apparatus. It is a very simple system, closely related to the alembic. Basically, you put a cork with a thermometer in it in the top opening, so the thermometer bulb is just below the sidearm, and use a small erlenmeyer or graduated cylinder to collect the distillate as it drips out of the sidearm. The major problems are that there is only air cooling on the sidearm, so low boiling compounds don't condense well, and the system is open at the drip tip so you can't distill flammable materials if you are using flame as a heat source.

I have seen these used with a second cork on the sidearm to fit a water cooled condenser, but if you're going that route, it isn't that much more expensive to use ground glass joints.

Endimion17 - 14-5-2012 at 06:40

You guys are joking, right? Come on, tell me you're joking. :(


[Edited on 14-5-2012 by Endimion17]

Magpie - 14-5-2012 at 07:41

There was a time when there was no TV, or ground glass fittings....

grndpndr - 14-5-2012 at 07:55

Ouch! :D
Ive got an old(HOLT,RINEHART,WINSTON H.S.Chemistry Workbook ,mid'50''s?,with an almost identical simple distillation setup.(sand baths
were still popular and glass blowing required.)Glass distillation retorts !etc, issued @ the beginning of the semester to each student as well as a list of issued chems's that today would surely warrant a home/school visit from ATF/DEA.
Another thing that may be on the way out is improvising whats needed for an experiment ,as long as it remains a safe excercise I rather enjoy trying to improvise equipment.

[Edited on 14-5-2012 by grndpndr]

Endimion17 - 14-5-2012 at 08:54

Quote: Originally posted by Magpie  
There was a time when there was no TV, or ground glass fittings....

This "time" still exists. Most schools don't want to spend money on expensive glass joints (+ Keck clips) because the only thing kids will see is water distillation. Therefore, standard setups like the one in the photo are widely used.

It's a "distillation flask". It's one of the things people recognize even if they aren't involved in chemistry because it's an icon of laboratory work, just like a test tube is. Or a Bunsen burner.