Waffles SS
Fighter
Posts: 998
Registered: 7-12-2009
Member Is Offline
|
|
Separation Aldehyde/Ketone
If Distillation dont help, may Oxidaton of Aldehyde work?(Oxidation to Acid)
I want to separate Ketone from Aldehyde.
[Edited on 19-3-2010 by Waffles SS]
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
Bisulfite adduct. http://en.wikipedia.org/wiki/Sodium_bisulfite
This should then allow the ketone to be separated from the bisulfite adduct by distillation.
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
Uh, Davster,
are you sure that ketones don't form adducts with bisulfite too?
|
|
|
Lambda-Eyde
National Hazard
Posts: 857
Registered: 20-11-2008
Location: Norway
Member Is Offline
Mood: Cleaved
|
|
All aldehydes form bisulfite adducts, but not all ketones do. That is if some other functional group doesn't interfere with the reaction.
If your ketone does not form a bisulfite adduct, they could easily be separated.
|
|
|
DJF90
International Hazard
Posts: 2266
Registered: 15-12-2007
Location: At the bench
Member Is Offline
Mood: No Mood
|
|
Run the mixture through a column 
[Edited on 19-3-2010 by DJF90]
|
|
|
Waffles SS
Fighter
Posts: 998
Registered: 7-12-2009
Member Is Offline
|
|
If ketone does form a bisulfite adduct then separation is impossible.
I think mild oxidant that has no effect on Ketone will be better but which one?
[Edited on 19-3-2010 by Waffles SS]
|
|
|
entropy51
Gone, but not forgotten
Posts: 1612
Registered: 30-5-2009
Member Is Offline
Mood: Fissile
|
|
You might actually get some helpful advice if you told us what these mysterious carbonyls compounds are.
I second Woelen's suggestion that threads that start out without identifying the subject chemicals be tossed into Detritus.
|
|
|
The_Davster
A pnictogen
Posts: 2861
Registered: 18-11-2003
Member Is Offline
Mood: .
|
|
Vague question, vague answer. 
Without knowing what aldehyde and ketone, my previous advice was as useful as 'distil, collect the fraction boiling at 80C)
|
|
|
Waffles SS
Fighter
Posts: 998
Registered: 7-12-2009
Member Is Offline
|
|
This is not for certain Aldehyde or Ketone separation.
For example separation Acetophenone from Phenylacetaldehyde
or
Propanone from Propanal
or
Phenylacetone from 2-phenylpropanal
...
I am looking for general method
[Edited on 20-3-2010 by Waffles SS]
|
|
|
not_important
International Hazard
Posts: 3873
Registered: 21-7-2006
Member Is Offline
Mood: No Mood
|
|
For example separation Acetophenone from Phenylacetaldehyde
Easy, bisulfite forms addition compound with aldehyde ArCH2CHO, but not with methyl aromatic ketone ArCOCH3
or Propanone from Propanal
harder, bisulfite readily forms addition compound with both. The boiling points are different enough that fractional distillation can be used to
separate them.
or Phenylacetone from 2-phenylpropanal
Both form bisulfite addition compound, although the aldehyde does do more readily and careful control of conditions will allow separation. Fractional
distillation is possible, although more difficult than for the C3 example. Oxidation will work, if all you care about is the P2P for cooking with.
Oxidation is not a universal method, as some ketones may be sensitive to oxidation at other points in their structure, or to other side effects from
the oxidation reagent.
Nor is oxidation properly a _separation_ as the aldehyde is destroyed, thus only works when all you care about is the ketone.
I am looking for general method
there ain't none, except buying the desired compound(s) and so letting others worry about the problem.
|
|
|
Waffles SS
Fighter
Posts: 998
Registered: 7-12-2009
Member Is Offline
|
|
Thanks not_important
What oxidant agent is suitable for oxidation of 2-phenylpropanal and propanal that has no effect on Ketone
Potassium Permanganate?Sodium Dichromate?
|
|
|
Nicodem
Super Moderator
Posts: 4230
Registered: 28-12-2004
Member Is Offline
Mood: No Mood
|
|
I think it was already explicitly made clear by several members on several occasions that playing this game is not tolerated. If you have drug cook
questions you must ask them openly so that members have a choice to either get involved or not (and moderators decide what to do with the topic).
Getting people involved into something they would never want to get involved by playing dirty is distasteful and only shows you know not what the word
dignity means!
Besides this question is on a beginners level and if you want to make illegal drugs, you should at least learn chemistry at a basic level.
|
|
|
Nicodem
|
Thread Closed
21-3-2010 at 12:23 |
![[*]](images/xpblue/default_icon.gif){kind=icon}
