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Author: Subject: Diacetone alcohol synthesis
reactofurnace
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[*] posted on 30-6-2019 at 19:24
Diacetone alcohol synthesis


Guys i'm going to attempt the condensation reaction of acetone to give diacetone alcohol. The procedures i've read calls for a soxhlet extractor with a barium hydroxide catalyst under reflux.
I do not have a soxhlet extractor so i was wondering if it is possible to conduct the reaction without it by just placing the barium hydroxide directly into the reaction flask and letting it reflux.
Would this work? What yield should I expect?


The article on the synthesis: http://www.prepchem.com/synthesis-of-diacetone-alcohol/
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bobm4360
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[*] posted on 30-6-2019 at 20:16


Slightly different procedure, but much better notes and background:

OrgSyn
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Metacelsus
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[*] posted on 30-6-2019 at 22:41


Quote: Originally posted by reactofurnace  
i was wondering if it is possible to conduct the reaction without it by just placing the barium hydroxide directly into the reaction flask and letting it reflux.
Would this work?


Not very well. Think carefully about equilibrium and vapor pressure of the reactants vs. products, and you'll see why they put the catalyst in the extractor and not the main reaction flask.

edit: if you're stumped, an explanation is in note 5 of the OrgSyn procedure

[Edited on 2019-7-1 by Metacelsus]




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Tsjerk
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[*] posted on 1-7-2019 at 08:19


I can imaging you could make some sort of improvised soxhlet by hanging a tea bag filled with BaOH in a reflux column, might be inefficient but also might work, refluxing acetone shouldn't cost too much energy anyway.

Edit: maybe hanging the teabag below the condensor but above the liquid would work, as the temperature is probably a bit higher there it would react a bit faster compared to the soxhlet, which does a cold "extraction".

[Edited on 1-7-2019 by Tsjerk]
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VSEPR_VOID
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[*] posted on 1-7-2019 at 18:00


It is an equilibrium process I think, so you need to keep diaacetone alcohol off of the barium hydroxide. This is why a soxhlet is used. The more volatile acetone boils off and is sent to the catalyst, well the product stays in the boiling flask.

I attempted doing this using a separator funnel and reflux condenser, the ghetto method, for 20 hours of reflux, but with no success. I think you really need to do this for a hundred hours at least. Make sure to use a condenser with a high efficiency and to regularly top off the reaction solution with fresh acetone.




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reactofurnace
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[*] posted on 1-7-2019 at 19:17


Quote: Originally posted by VSEPR_VOID  
It is an equilibrium process I think, so you need to keep diaacetone alcohol off of the barium hydroxide. This is why a soxhlet is used. The more volatile acetone boils off and is sent to the catalyst, well the product stays in the boiling flask.

I attempted doing this using a separator funnel and reflux condenser, the ghetto method, for 20 hours of reflux, but with no success. I think you really need to do this for a hundred hours at least. Make sure to use a condenser with a high efficiency and to regularly top off the reaction solution with fresh acetone.


20 hours and no success!! wow that must have been a real bummer. Yes , perhaps this reaction needed to be conducted for long periods.

Were your reagents dried?

[Edited on 2-7-2019 by reactofurnace]
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