August 11, 2020, 06:32:40 AM
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Topic: Recrystallization Solvent ?  (Read 230 times)

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Offline TrevorGage

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Recrystallization Solvent ?
« on: March 18, 2020, 01:28:32 AM »
What to recrystallize methyl 3,5-dibromobenzoate from?

Literature says ethanol but it doesn't work. Compound precipitates and does not crystallize.

Melting point is 63 C.omegle discord xender


I have also tried DCM, or DCM/hexane and the same thing happens.

Offline hollytara

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Re: Recrystallization Solvent ?
« Reply #1 on: March 18, 2020, 08:56:34 AM »
You get a powder (microcrystals) instead of discernible crystals? 

I always like to recrystallize methyl esters from methanol if using an alcohol - no chance of transesterification.

If you are getting a powder, that means the temperature/solubility curve is very steep - so you can suddenly become greatly oversaturated and have rapid crystallization. 

You can - dissoive to saturation at room temperature.  Then add a known amount of extra material - don't saturate at hgh T. 

Or - lower the temperature more slowly. 

Offline pgk

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Re: Recrystallization Solvent ?
« Reply #2 on: March 18, 2020, 01:46:48 PM »
Try recrystallization with ethanol containing a little THF. It may work.

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