roXefeller
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p-cresol purchase
I ordered up a 4g quantity of p-cresol recently and when I arrived I discovered I was sent a vial of translucent orange colored liquid (even after I
chilled it). I knew it had a melting point in the 30's and I'm scratching my head. Before I file a complaint, as a sanity check am I missing
something here? It was sold and is labeled specifically as the para isomer.
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TheChemiKid
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How cool did you chill it? I do know the meta isomer is liquid a RT, only freezing at 11°C.
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unionised
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have you thought of this?
http://en.wikipedia.org/wiki/Supercooling
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roXefeller
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Supercooling is a possibility since it is in a smooth glass vial and possible got hot during transit. I just pulled it out of the freezer and it
still flows, though more viscous. When I dropped a grain of salt in to seed it, nothing froze. It smells a bit like camphor though. Following that
I've added it to a NaOH solution. It formed an immiscible phase at first, but on warming it dissolves.
[Edited on 16-8-2014 by roXefeller]
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UnintentionalChaos
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Don't assume salt will seed a dissimilar substance, especially since salt forms small cubic crystals with relatively low surface area. Try a crumb of
boiling chip instead.
I think I had issues with my p-cresol supercooling as well.
Department of Redundancy Department - Now with paperwork!
'In organic synthesis, we call decomposition products "crap", however this is not a IUPAC approved nomenclature.' -Nicodem
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Boffis
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Traces of water can also significantly depress the melting point of some simple phenols, particularly phenol itself. This is what "liquid phenol" is,
its about 95% phenol and 5% water and liquid at room temperature. I can imagine that p-cresol will act similarly. How you dry it is another matter,
maybe azeotropic distillation with say toluene might work. The water content is likely to be small if that the problem. The other possibility is that
it is mixed with another isomer and this has depressed the melting point after all p-cresol melts at 35 and o-cresol at about 31 C. I have a large jar
of p-cresol and it never liquefies even in warm weather but it is a pale pinkish crystalline material if yours is a brown liquid it doesn't sound very
pure.
Maybe try distillation, if cresol and water don't form an azeotrope then simple distillation will probably be sufficient to separate the water and
then further distillation to remove the coloured impurities (hopefully!). Check out google.
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roXefeller
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The response after my seller got the certificate of analysis:
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I received a message back, they told me it is very common for this compound to be in a liquid state even at 98+% purity. I have found the same to be
true of other hydroxyl compounds. Can I ask if you had a plan for it and if it worked well regardless?
The p-cresol that I have left, the same that I put in the freezer to test, is still about half frozen in white crystals regardless of the fact that it
has been a few days and my room temperature here is about 75.
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