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posted by  green rose on 10/23/2008 7:53:26 PM  |  status: Live  

recystallization

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Organic Chemistry N/A N/A N/A
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what criteria should you use to determine wheter recrystallization or sublimation will be a better method of purification?
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posted by Arcanum on 10/23/2008 10:41:30 PM  |  status: Live
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green rose's comment:
"thanks"
Response Details:
Well, here is the skinny on sublimation and recrystallization: (Heeheh, I haven't said that phrase in an age or two :+) )
 
Anyways, the advantage of using sublimation is that no solvent is used and that later on, none will be needed to be removed. Sublimation also removes any occluded material, such as molecules of solvent, from the substanced that you sublimed.
 
Now, to be of importance to your question, know that sublimation is generally faster in purification than crystallization but you can't be as selective. Reasons, is that similar vapor pressures are pretty often a factor in when dealing with solids that sublime, in which little separtion can be achieved and recrystallization would be a better method. So, most often recrystallization is used on solids for purfication rather than sublimation.
 
Keep in mind, that Sublimation is most effective in removing anything that is volatile even from a nonvolatile compound. I hope I haven't confused you more and hope that this was some help to you :+)
 
If you have any further questions about this feel free to PM me :+)
Pffhh, if I knew everything, I would spend my entire time on here answering questions, but until then ill spend my entire time on here asking questions... :+)
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