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Author: Subject: Purify the benzoic acid from a mixture with benzyl alcohol.
Maddr33
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mad.gif posted on 15-3-2015 at 01:24
Purify the benzoic acid from a mixture with benzyl alcohol.


I would love to show crystallization.
Solvents: acetone, ethanol, methanol, ethyl acetate, hexanes, dichloromethane
Aqueous solutions: 1M NaOH, 1M HCl, 3M NaOH, 3M HCl, 1 M NaHCO3, saturated NaCl
Drying Agent: sodium sulfate
I wish there were a sim lab where I could mix these things and practice extraction.
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madscientist
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15-3-2015 at 02:18
Boffis
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[*] posted on 15-3-2015 at 09:23


Neutralise the acid with dilute NaOH and steam distil or extract with immiscible solvent, of those listed probably hexane is best and fractionate the extract. You don't need much solvent because benzyl alcohol is pretty insoluble in aqueous salt solutions anyway. If you have produced this mixture by Cannizzaro's reaction from benzaldehyde you should get phase separation anyway. Check out Vogel's Textbook of organic chem.

The free acid can be recovered with dilute HCl on the aqueous phase.
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Maddr33
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[*] posted on 15-3-2015 at 14:10


thanks you...
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sparkgap
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[*] posted on 15-3-2015 at 16:46


Sodium hydroxide will work, but even a bicarbonate solution will do the job for extraction, after which you do the requisite acidification and salting out to net your benzoic acid.

sparky (~_~)




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