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Author: Subject: fractionating column help?
Funkerman23
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[*] posted on 14-6-2013 at 21:10
fractionating column help?


To make a lot of waffling less: I'm trying to fractionally distill a sample and my 'column' does not have the indentations/prongs at the bottom; what can I do to use the condenser as a fractionating column? I've considered using an adapter like this one http://www.ctechglass.com/images/AD-0057b.jpg but I'm fairly certain that the frit would flood at some point( the viscosity of the liquid would be a factor as well). .any ideas are greatly appreciated. If this has been asked please forgive me but in any event I thank you and wish you the best yields.



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elementcollector1
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[*] posted on 14-6-2013 at 21:37


If you can get a plain glass tube, jointed on either end, and fill it with small glass beads, that seems to work just as well.



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Funkerman23
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[*] posted on 14-6-2013 at 21:53


Quote: Originally posted by elementcollector1  
If you can get a plain glass tube, jointed on either end, and fill it with small glass beads, that seems to work just as well.
I had tried that but I keep having the media/ glass beads come out of the tube, dumb as that may sound.



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Organikum
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[*] posted on 14-6-2013 at 22:41


If it does not conflict with what you distill a stainless steel scrubber pad (or a part thereof) should do nicely.
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[*] posted on 15-6-2013 at 08:05


The frit would flood, no doubt about that. It would flood, and the vapor couldn't pass through it, leading to a sharp increase of pressure in the distilling flask. If the flask is strong enough, the joints would separate. Pressure would drop suddenly and the distilling liquid would turn to a blob of gas, shooting out. That would be a major hazard, even if it's not flammable or corrosive.
If the apparatus is tightly jointed, with the clamps and everything holding it very tight, and the flask is not strong enough, it would explode.

Either way, you're fucked, or the lab is. So don't even think about frits.

Organikum has s good point. If you're distilling something neutral, organic, fresh steel wool is a great way to make a column, but be careful not to stuff it. It can become saturated at the bottom, flooding and shooting liquid into your cooler.
I actually had such issue even with a proper Vigreux column, when the temperature difference was so great that all that disstilate rain from above simply choked the column and in a matter of 1-2 seconds it just burped stuff into the Claisen adapter above. It was scary, because I was distilling gasoline. Pack your column carefully.

You can even use a small steel spring on the bottom of the condenser, but don't use a flimsy one because at higher temperatures, they might fail. Also don't use a strong one to avoid damaging your condenser. After the spring is positioned, carefully load the beads, but I recommend you to make Raschig rings. They offer more surface and the less chance to flood up the system.




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[*] posted on 16-6-2013 at 02:09


I have two possible solutions:
1: break an old glass jar an find a piece that fits in the top of the condenser but not out the bottom. This works for me because my condenser is slightly tapered at the end, but I dont know if all condensers are like this. Once you've got that stuck in the bottom, fill the rest up with glass beads. It'll probably take some fiddling, but there you go.

2: grab a piece of stainless steel cable slightly shorter than the length of your condenser. Unwind the 5 or so strands that make up that cable, but leave a little bit left unwound, to stop the whole thing falling apart.
You can stick this unravelled pice of cable into your condenser, and it should stick there without falling down. This unravelled cable will provide lots of surface area like steel wool, but runs no risk of becoming flooded.
The type of cable I am talking about can be found here: http://www.alliedirrigation.com/products/191-stainless-steel...




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