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Author: Subject: azeotrope -- diethyl ether and heptane
jamit
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[*] posted on 19-11-2014 at 07:54
azeotrope -- diethyl ether and heptane


I'm about to distill starter fluid to get diethyl ether but its mixed with heptane (and co2 for propellant). I can't find anything over google as to whether diethyl ether and heptane forms an azeotrope.

Am I right to assume that this is just a straight distillation since the bp of diethyl ether is 35C and heptane is 98C.

Any help on whether diethyl ether and heptane form an azeotrope? thanks.
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Nicodem
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19-11-2014 at 07:59
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[*] posted on 19-11-2014 at 10:26


This might be useful http://www.youtube.com/watch?v=SLWwwod-u-Q&list=UUFhXFik...
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UnintentionalChaos
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[*] posted on 19-11-2014 at 10:27


They don't form an azeotrope, but the mixture is annoyingly difficult to separate. You should slap your longest column on it and pull the ether very slowly off so that the stillhead stays at 35C.

See also http://www.sciencemadness.org/talk/viewthread.php?tid=9747

[Edited on 11-19-14 by UnintentionalChaos]




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jamit
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[*] posted on 19-11-2014 at 11:59


Quote: Originally posted by UnintentionalChaos  
They don't form an azeotrope, but the mixture is annoyingly difficult to separate. You should slap your longest column on it and pull the ether very slowly off so that the stillhead stays at 35C.

See also http://www.sciencemadness.org/talk/viewthread.php?tid=9747

[Edited on 11-19-14 by UnintentionalChaos]



Thank you for that info. Have you tried separating it yourself?
Why is it difficult to separate if the Bp difference is 95-35= 60c. Shouldn't it separate easily without a column? Just wondering.
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blogfast25
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[*] posted on 19-11-2014 at 14:29


Quote: Originally posted by jamit  
Shouldn't it separate easily without a column? Just wondering.


Yup. Me too. Why a column with such a large delta BP?




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HeYBrO
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[*] posted on 19-11-2014 at 18:30


I tried this yesterday and just used a hot water bath, and most of the ether came over at ~30-4 degree C. Nice and simple, and i was using a 14/20 setup. However, make sure you have a nice long, ice cold condenser, as i didn't recover much with my 150 mm condenser.
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