redox
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Crystal Separation
Hello all.
Recently I was digging through my father's old photo-developing stuff, and I found (among many other chemicals) a tin can containing Kodak
Photo Developer D-76. On the label is listed that it contains p- methyl aminophenol sulfate and hydroquinone. I am interested in isolating the latter,
for use as a starting point in organic synthesis.
Does anybody have any thoughts of how to separate these substances? I was thinking along the lines of a solubility difference in a solvent,
but little solubility information of these compounds is published on the internet.
Any ideas?
p.s. It is a homogeneous white powder
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Mindchemist
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Try heating it to 180C. The hydroquinone will melt while the metol will remain solid.
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redox
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I considered that method, but it may be difficult to execute. 180C is a little hot for me. Plus, what if the metol is soluble in the molten
hydroquinone?
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HydroCarbon
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Just a thought, but you might be able to recrystallize in water. I would imagine the metol to be a good bit more soluble in water. But I could be
wrong...
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GreenD
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Solubility of hydroquinone: 5.9 g/100 ml (15 °C)
The solubility of the other product would be nearly 100% due to it being a salt. (atleast thats what I'm seeing!).
I think also if you added a bit of NaCl to the water it would help with the solubility of the prior, and increase precipitation of the latter.
Pretty sure you can take that to the bank 
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smuv
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you could probably just triturate that stuff with butanone, the hydroquinone will dissolve the aminophenol should not. After that go for a
recrystallization, I don't know a lot about the solubility of sulfate salts, but probably with MeOH/butanone you could come up with a good system.
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smaerd
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edit woops had that backwards
[Edited on 4-4-2011 by smaerd]
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redox
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I don't think water solubility separation is an option. The solubility of methylaminophenol sulfate is 5 g/100 mL, almost the exact same as
hydroquinone.
Quote: Originally posted by smuv  | | you could probably just triturate that stuff with butanone, the hydroquinone will dissolve the aminophenol should not. After that go for a
recrystallization, I don't know a lot about the solubility of sulfate salts, but probably with MeOH/butanone you could come up with a good system.
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I think this is the best option.
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