Vanry
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steam distillation problem - condensation before main flask
Hi everybody !
Another messy post (bad month in my lab  )
I tried to steam distill some stuff, first time I tried this.
To be specific my steam distillation was done with the steam source outside of the flask containing the reagent (it wasn't an hydrodistillation).
I'll post pictures later but to sum-up, but quickly, almost all apparatus is glass, except a rubber tubing connecting the two three neck flask.
and here comes the problem, as steam is generated, it bubbles a lot when it start (I was very happy for approximately 5 seconds) and then a bit of
water condenses in the tube and start ruining everything, increasing pressure in the steam sources, siphoning a bit of the main flask... well... not
really what I hoped for.
so here comes the question part:
how to improve the setup ? How is that done in a professional way ?
Can I punct a hole into the lowest spot of the tube to let condensed water flow out, or will it be useless ? I don't really like to throw away brand
new tubing or burn myself with steam. I have the ability to make a connector with a piece of steel tubing pierced, can it be usefull ?
and if nothing work, is it possible to simply do an hydrodistillation instead of a steam distillation, my product is not water or heat sensitive, so
in theory it doesn't change anything am I wrong ?
thank you in advance for your answers, hoping your help will make something work in my lab before the end of the century x)
[Edited on 12-7-2018 by Vanry]
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happyfooddance
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You must heat the flask with your product gently, to about 100°C (or a little less) before you admit the stream of steam. Did you just leave it room
temperature? It sounds like it, and if you did then your product is just acting as a condenser.
If you are still having a problem, you can set up a "steam trap". You can make one pretty easily; google it to get an idea.
Also, just insulating the tube from your steam generator to your boiling flask with a little Al foil will help a lot, and should be done anyway.
Good luck 
[Edited on 7-12-2018 by happyfooddance]
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Magpie
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see my post here:
https://www.sciencemadness.org/whisper/viewthread.php?tid=61...
The single most important condition for a successful synthesis is good mixing - Nicodem
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Vanry
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Ok so:
aluminium foil, everything: I'll try ^^
I was heating my main flask, but I don't have two heater so I repurposed a heat gun... it was not RT but not even close to 100°C. maybe to 50°C.
I got a steam injection tube, and a pretty good liebig, not very long but with a very thin inner wall. but in my case, steam don't even get to the
flask, i'll think later about problem past the condenser...
A steam trap is basicaly a piece of tube with a little tank and a valve. May not be too hard to do. I read your post about Salicylaldehyde @magpie.
Impressing. And a cleverly unusual use of a separatory funnel, as a steam trap, I'll try something like this, but I'll have to improvised a two-hole
plug.
anyway, thank you for this tips, going to try it out tomorow 
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happyfooddance
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A heat gun is probably just fine for once everything gets to temp, but 50°C is way too cold to start. That's a whole 50° lower than the bp of water!
As a comparison you were to run 50° water through your condenser it would condense almost all the water.
Temperature control (and vapor flow rate, closely related) is key to successful steam distillation.
Also, you mentioned that at first there was some bubbling and you thought everything was good... If I had to bet I would say that this was right after
your steam generator started boiling. This is just air being pushed out of the steam generator. As soon as all that air is pushed through, then your
steam comes. But in your case it condensed and that's why it started to suck back. If your main flask is about 90-95° this shouldn't happen.
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Vanry
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Some new here !
I rearanged my apparatus:
- created a steam trap with a bit of cork with two hole, two tube and a separating funnel.
- change the steam source from 3 necked RBF + oil bath to a camp stove and a reactor (reactor is a classy name for "repurposed paint can" with a
drilled hole)
- use the now free hotplate to oilbath my main flask and heat it to ~90°C
Drawback: can't use it for very flammable solvent and a camping stove is not really fire-proof
But, it worked ! almost perfectly ! 
I had to re-seal everything with a bit of teflon, and I putted too much water in the reactor, causing bumping and difficulties to manage steam rate in
the begining, but after 30m everything became a steady steam distillation, as a book would describe it ! 
It is wonderfull !
Big thanks to everything here
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happyfooddance
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Good job! Don't forget to put boiling chips in your steam generator!
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lab-equip
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https://forum.lambdasyn.org/index.php/topic,2030.msg10239.ht...
see there one of my work ups with pictures
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