LuckyWinner
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Distilling High Temperature Chemicals - Insulate Vacuum Distillations?
I have a chemical that boils at 300C
my vacuum can lower this boiling point to around 150C.
I see the chemical melt and boil in the RBF inside the oilbath
but it does not reach the condenser and just coats the RBF.
this means the upper part of the RBF is too cold and condenses all
the product at its top.
I need to alufoil wrap it to make it come over?
I already did that and it did not work.
more alufoil? or use an aluminium heating block coated in 5 layers of alu foil
up to the condenser?
use an air condenser for this 150C hot steam?
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monolithic
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I've had similar problems in the past, even with a short path condenser. I ended up treating the short path as an air condenser (no fluid through the
condenser jacket) and gently heated the top of the flask and the "still head" with a heat gun. Eventually it warmed up enough to bring over the
distillate. You could try a hair dryer, might be hot enough, but a heat gun will definitely work.
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Fyndium
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If using a bath of sort, you could cover it containing the stillhead with al foil to create a space which is heated by the bath.
Or then use more heat input. Or push air into this containment with heat gun or hair dryer.
Bleeder tube could also help as the little airflow could carry vapors over, unless it's air sensitive - or then use inert gas.
If one has short path, the flask can be tilted so the condenser is almost parallel with the liquid surface so vapors are carried to the condenser with
very little vapor pressure.
[Edited on 1-10-2020 by Fyndium]
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