Could someone identify the strange (to me) funnel in the linked image? It seems a bit sub-optimal. The tiny frit is below the stopcock, so that any grit might damage the teflon or jam the
stopcock. And it seems hard to clean. Does one put a piece of filter paper at the bottom of the cone?
edit: I now think it is a chromatography column meant to be used with a cotton ball in the neck, with the glass frit catching any remaining fine
particulates.
[Edited on 28-1-2013 by GammaFunction]kavu - 28-1-2013 at 14:43
It looks like a dropping funnel with a gas outlet. It's not supposed to be used as a filter funnel. One might also do a quick filter through a pad of
silica with that, though.
[Edited on 28-1-2013 by kavu]GammaFunction - 28-1-2013 at 14:52
It looks like a dropping funnel with a gas outlet....
I guess what seems strange to me is 1) the small frit, which indicates some filtering function 2) the 'gas outlet' seems, to my eyes, to be a vacuum
port and 3) the open top, which is unusual for a dropping funnel, and seems to sugggest that it is meant to be packed with stuff.
If there were a big frit above the stopcock, I'd call it a chromatography column. Maybe pack neck with cotton or fiberglass, fill with chromatography
stationary phase, and rely on the frit to mop up last bits of particulates that make it through the cotton?
kavu - 28-1-2013 at 15:31
Gas outlets can be used to suck vacuum as well and vice versa (with some restrictions of course). Some models of dropping funnels don't have a ground
joint at the end, I've had a few of those. The frit makes it a bit more interesting, it might be useful for a quick column as stated. Anyhow it's a
piece of specialized glassware. How fine is the frit and can you take a picture from another angle?
[Edited on 28-1-2013 by kavu]kristofvagyok - 28-1-2013 at 17:03
We use these kind of funnels for flash chromatography. Just fill it with silica (or cellulose ect.), place the mixture of your substances on the top,
fill it with the chosen eluent and "pull it down" until you've got what you need.
It could be only used if there is an enough big Rf difference between the needed compound and everything else. It could be a really quick and easy
method for purification.chemrox - 28-1-2013 at 18:02
I have one a bit longer that came with some other oddities from ebay. This is not an oddity as unpronounceable states-it's a flash chromatography
vessel. I have no idea what a "gas outlet" would be doing at such a location. That is clearly a vacuum fitting. It's a good thing for a beginner in
organic experimentation to look for on ebay because 90% of the time the seller won't have a clue and the price will be cheap. I have a larger one
without the frit that looks like it was put together by a glassblower. A small circular frit with polished circumference could be dropped in but its
100 mm diameter makes it an expensive cleanup tool. Maybe I could use Tide soap for the solid phase .. GammaFunction - 28-1-2013 at 20:32
We use these kind of funnels for flash chromatography. Just fill it with silica ....
Thank you (and chemrox). This is what I suspected. What threw me off was the lack of frit above the Teflon stopcock (because Teflon is a bit soft,
and might get scratched by a coarse medium.
Is it true that one has to place cotton balls or glass wool in the neck? chemrox - 29-1-2013 at 17:16
You would use a frit or glass wool. Otherwise the hole in the stopcock would probably get clogged. I also realized this funnel could be used as a
percolation funnel for making herbal extracts in the historic manner (well one of them anyway). But it's probably too small for that. If you decide
against it please p2p me the url.
