Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
Distillation using an air condenser
Has anyone done a distillation with an air condenser?
Such as a long tube routed from a stoppered erlenmeyer?
What diameter tube is most versatile/best. Any advice on said distillations? Chill the receiver?
Last question. I posted this here because it's it's own subject. Please let me know why all my questions are getting moved to one thread. Thank you
Edit by Texium: changed title for clarity
[Edited on 3-19-2018 by Texium (zts16)]
|
|
|
Magpie
lab constructor
Posts: 5939
Registered: 1-11-2003
Location: USA
Member Is Offline
Mood: Chemistry: the subtle science.
|
|
Yes, I have done them with a regular condenser without any coolant. I've also used a 3 foot long 8mm glass tube. I also keep a heat gun handy if the
product solidifies in the condenser.
The single most important condition for a successful synthesis is good mixing - Nicodem
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
I'm thinking of yanking apart a nearby fridge to get the copper tube from the ice maker out.
Maybe salvage up the polypropylene tubes too
The compressor seemed to be more trouble than it was worth last time.
|
|
|
Texium
Administrator
Posts: 4516
Registered: 11-1-2014
Location: Salt Lake City
Member Is Online
Mood: PhD candidate!
|
|
Your questions were getting merged into one thread when they were silly and easily google-able. This isn't Yahoo Answers. This thread is alright, but
I changed the title because there are hundreds of threads about "Distillations" on this forum. A good discussion on the use of air condensers wouldn't
be bad though.
|
|
|
Bert
Super Administrator
Posts: 2821
Registered: 12-3-2004
Member Is Offline
Mood: " I think we are all going to die. I think that love is an illusion. We are flawed, my darling".
|
|
Air condenser work for some applications, particularly if the throughout is pretty low. Plenty of moonshiners don't bother with a water jacket if it's
winter and they are working outdoors.
Axt did make a Copper condenser for his destructive distillation of benzoic acid for over the counter benzene production, see the pentryl thread. I
recall it being a tube inside another Copper tube, with water cooling though, rather than a plain air condenser..
Soft Copper tube is always good to have around, as an easily worked, easy to solder tube for quick engineering projects, as a reagent, a conductor for
electricity, a heat sink... Tons of uses. Heck, you can even use it for plumbing!
There are a fair number of online descriptions of repurposing refrigerator compressors as vacuum pumps- If it still runs, and you are doing any
chemistry that would benefit, this might be something to consider.
If you are good with expanding on your questions a bit beyond one quick sentence with no context? Do some work on explaining WHY you have the
questions and googling for yourself before asking the simple, easy ones? Try to ask a question in an existing thread, best of all? I will be happy to
leave your threads where and as you put them.
Welcome back-
|
|
|
Sidmadra
Hazard to Others
Posts: 129
Registered: 17-2-2017
Member Is Offline
Mood: No Mood
|
|
It's worth mentioning there are tons of different configurations with air condensers. Some just use passive cooling, taking advantage of surface area
of the condenser, some specialized glass air condensers actually have a metal heat exchange around them, and you could even wrap copper tubing around
to blow in front of a fan to provide really decent heat exchange.
There's this one company that makes a purely glass air condenser that has some really decent reflux power. The condenser has a baffled and curved
design which supposedly helps the process. They have a chart on the page showing different solvents able to be refluxed in oil baths at different
temperatures with minimal solvent loss: https://www.asynt.com/product/asynt-condensyn-air-condenser/
I wanted to get one but they start at like $200 or something.
|
|
|
Reboot
Hazard to Others
Posts: 141
Registered: 8-8-2017
Member Is Offline
Mood: No Mood
|
|
Neat!
For those on a budget, there's always the classic distillation retort:
https://en.wikipedia.org/wiki/Retort
You can still buy them on eBay anyway if you're feeling sentimental about the truly old school methods. :-)
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
so you can reflux in a retort? Just by tilting it on its side?
There is a 25ml distillation flask that looks pretty interesting.
also a 250ml glass distillation apparatus -- wondering what all it could be used for, it looks like a retort, but with a bit of a modern element to
it.
what about one of these
[Edited on 3/20/2018 by Yttrium2]
|
|
|
S.C. Wack
bibliomaster
Posts: 2419
Registered: 7-5-2004
Location: Cornworld, Central USA
Member Is Offline
Mood: Enhanced
|
|
Air condensers are used for high boiling or crystallizing distillates; it's stupid or at least slow to not use water when water should be used. I have
an old ~250 mm that has a water tube attachment but is otherwise a Liebig condenser without a jacket. So the performance using an actual Liebig will
suck in comparison unless you at least blow a fan on it of fill it with something.
Know WTF you're doing or learn with teaching moments. Do you know how much easier it is to condense heptane than water? Yes indeed glycols can boil
high but if you use air, your condenser will be really long and really hot unless you've got a few days.
I bought a retort for special situations, times when you don't want your glassware to fail, so it's never used.
One should settle for nothing less than an old but complete 19/22 Kimax kit on ebay from some tiny college.
|
|
|
Sulaiman
International Hazard
Posts: 3558
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
Quote: Originally posted by Yttrium2  | I'm thinking of yanking apart a nearby fridge to get the copper tube from the ice maker out.
Maybe salvage up the polypropylene tubes too
The compressor seemed to be more trouble than it was worth last time. |
Domestic refrigerators that I have looked at have very small bore tubing,
the condensate would spit out of the tube in bursts and everything start jumping and bumping.
Even with larger diameter tubing you have to ensure that the liquid condensate path is always downhill,
otherwise, drops form into puddles form into traps - and spitting occurs.
I once (Ta c20C) tried a 9mm i.d. 1.5m long glass tube as an air condenser for ethanol heated by a cheap 1500W hotplate;
- 1.5m was not long enough - not all of the vapour was always condensed
- even with a straight, inclined, 9mm bore: 'blobs' of condensate blocked the tube then got spat out.
Just remember, the condenser has to remove the heat of vaporization.
So for me to expect a 1.5m glass tube at below ethanol b.p., in ambient air, to dissipate 100's of Watts was, to say the least - optimistic 
I have disposed of refrigerators in the past;
UK/EU regulations are enforced - at least here in West Midlands.
My local council is obliged to collect unwanted refrigerators and freezers FREE OF CHARGE.
Once you break the gas seal you may find it difficult to dispose of.
OTOH
I (my other half) shall soon be disposing of a small fridge and a freezer,
the storage and cooling-power of a used fridge would be great for my chemistry hobby - if I can make some space.
P.S. I now use a calculator for the dissipation of heat by tubes in air.
http://www.paroc.co.uk/tools-and-documents/calculators
and
The intact refrigerator radiator may be useful for re-circulated condenser cooling water, with additional cooling via ice/TEC/refrigeration etc.
or, depending upon production rate, heat of vaporization, condenser efficiency, b.p., ambient temperature...... without additional cooling 
[Edited on 21-3-2018 by Sulaiman]
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Melgar
Anti-Spam Agent
Posts: 2004
Registered: 23-2-2010
Location: Connecticut
Member Is Offline
Mood: Estrified
|
|
I set up a liquid-cooled system that used a CPU heatsink and two 60W 12VDC thermoelectric coolers for distillation. It could hold a 14/20
distillation setup to about 15˚C pretty easily, which is fine for most solvents. Temperature would go up for distillates with higher BPs, which
usually didn't matter much. If I needed it colder, I'd just dump a bunch of ice cubes into the coolant tank. The ice would eventually melt, but not
nearly as fast as it would have without the coolers.
http://www.sciencemadness.org/talk/viewthread.php?tid=80597
The first step in the process of learning something is admitting that you don't know it already.
I'm givin' the spam shields max power at full warp, but they just dinna have the power! We're gonna have to evacuate to new forum software!
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
Back to the idea of an air condenser being built out of a glass tube atop a stoppered 250mL Erlenmeyer---
The balloon atop for reflux : is there a particular material/thickness of balloon to employ?
And
What if the tubing O.D. is say 10mm-12mm, - won't condensate accumulate in the gap of the balloon between it and the tubing? Do I need a thicker tube
condenser for the balloon to wrap around to ensure condensate falls down center INTO the tube?.... Should the end of the tubing be flared out so the
balloon stretches so there isn't a gap between balloon and glass tube condenser?
If im not mistaken the balloon acts as a condenser, during reflux, and allows material to drop from the top of the balloon down into the tube, and
down into the reaction flask?
How much material can be reacted in this contraption? It avoids water pumps, stands, ice bath, and all the grief associated with it.
[Edited on 12/28/2019 by Yttrium2]
[Edited on 12/28/2019 by Yttrium2]
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
Bump
Should a simple jacket ice water jacket around the glass pipe be implemented? I think so
|
|
|
Sulaiman
International Hazard
Posts: 3558
Registered: 8-2-2015
Location: 3rd rock from the sun
Member Is Offline
|
|
Simple glass tubing works as an air condenser but the cooling power is quite low,
e.g. condensing 100oC water vapour with 20oC ambient temperature,
8mm od = 30 W/m, 16mm od = 60 W/m approximately.
So to condense e.g. 100ml water per hour,
2257 (J/g) x 100 (g) /3600 (seconds/hour) = 62.7 W
which would require approx. >2m of 8mm tubing, or >1m of 16mm tubing !
this is why water cooled condensers are so popular
___________________________________________
For high b.p liquids an air condenser is practical,
e.g. b.p. = 320oC, ambient = 20oC, diameter = 25mm (one inch)
cooling power is approx. 600 W/m
also
having a 320oC vapour condensed by 20oC water would be a 300oC temperature difference across the glass,
which is a very high thermal gradient that would probably crack the glass.
CAUTION : Hobby Chemist, not Professional or even Amateur
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
What about the idea of using a balloon for reflux?
If the diameter of the tubing is say 12mm OD, won't there be a gap between the balloon and tubing ?
|
|
|
Yttrium2
Perpetual Question Machine
Posts: 1104
Registered: 7-2-2015
Member Is Offline
|
|
Can anyone explain the balloon condenser? I know this may seem elementary...
Please help me! Im confused about the diameter tubing the balloon condenser must go over for it to work. I don't want my drips to land and pool up
between the balloon and the tube but I want them to drop from the balloon down into the tube.
Any help much appreciated
[Edited on 12/29/2019 by Yttrium2]
|
|
|
![[*]](images/xpblue/default_icon.gif){kind=icon}
