beeludwig
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Separation of paraffin wax
Paraffin wax is just a mixture of long chain aliphatic carbons right?
Would it be possible to separate them based on their different melting points? Or are the different components too close together in melting point to
effectively separate this way?
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j_sum1
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Melting point, no. How on earth is a long chain molecule that reaches melting temperature going to escape the bulk of material that is still solid.
Boiling point, maybe. Now you are in the realm of fractional distillation. I am not sure how easily you can fraction something like paraffin wax,
but then, I have never tried.
Good luck.
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unionised
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Fractional distillation's not going to work much better than melting point.
You are beyond the realm of fractional distillation, and into the realm of chromatography.
https://www.agilent.com/cs/library/applications/A00773.pdf
And even this isn't that good at separating all the components.
You might get some sort of fractionation by crystallisation.
[Edited on 28-5-19 by unionised]
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beeludwig
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I see what you guys mean. Do you think natural waxes, bee's wax etc, would be any easier to separate? or is that still in the fractional
distillation/gas chromatography land.
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Pumukli
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Beeswax is not paraffin, it's a different animal chemically. But I don't see why would it be easier to separate its components physically.
Wouldn't it be easier to synthetize a well-defined paraffin molecule by the known methods? Of course it would be more expensive than starting from
cheap paraffin, but at least you could be sure what you have is chemically pure in the end.
What is the purpose of this all, besides brainstorming?
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beeludwig
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Well... at this point it’s 99% brainstorm. It’s not exactly a linear process. So originally here’s what happened. I requisition some well
defined fatty acids at various carbon lengths. The purpose of which would be to do a really nice little lab with my chem students about chemical and
physical properties and intermolecular forces and all that. So then I thought, hey why don’t we take a real life mixture and see if we can’t
separate the mixture based on boiling points. Paraffin wax was sitting on my desk for a different project and so I thought it might work. But
obviously it doesn’t. We don’t even ha e a simple distillation kit. Well... we do but it doesn’t work because I can’t get them to fix the
faucet in my sink (public schools, whatyagonnado?) so it’s not a huge deal of it doesn’t work. We might make soap or something instead. I even
thought about doing some hydrogenation or dehydrogenation. But I’m not sure that’s possible with what we have. Basically the labs need to be free
or close to it.
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SWIM
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Natural waxes from biological sources have functional groups on them, so separation by chromatography or other means might be easier than with regular
old alkanes. Beeswax is just full of esters.
[Edited on 28-5-2019 by SWIM]
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unionised
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As a teaching exercise you might be able to freeze (mainly) triolein out of olive oil.
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Ubya
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You could try to saponify beeswax and break the major component triacontanyl palmitate, separating the long chain alcohol (it has growth hormone
features for roses). Plus a really long alcohol is just unusual (for simple chemistry)
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DraconicAcid
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You can actually do a distillation without running water- attach the hoses to the stems of two funnels, which are supported at an approximately equal
level with ring stands. Pour ice water in one funnel. Raise or lower the other one to get cold water flowing slowly through the condensor,
replenishing the ice as needed.
Please remember: "Filtrate" is not a verb.
Write up your lab reports the way your instructor wants them, not the way your ex-instructor wants them.
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beeludwig
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That’s really awesome idea. If they can’t fix the sink in time for classes this fall I’ll have to try that. I refuse to ha e chemical equipment
collecting dust.
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Fulmen
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Quote: Originally posted by j_sum1  | | Melting point, no. How on earth is a long chain molecule that reaches melting temperature going to escape the bulk of material that is still solid.
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You know the MP can be approached from both directions? Freezing out might work, although I wouldn't expect miracles.
[Edited on 29-5-19 by Fulmen]
[edit]
Apologies Fulmen. I hit edit instead of reply. Error fixed.
[Edited on 29-5-2019 by j_sum1]
We're not banging rocks together here. We know how to put a man back together.
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j_sum1
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| Quote: Originally posted by Fulmen | | Quote: Originally posted by j_sum1 | | Melting point, no. How on earth is a long chain molecule that reaches melting temperature going to escape the bulk of material that is still solid.
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You know the MP can be approached from both directions? Freezing out might work, although I wouldn't expect miracles. |
True. But like you I doubt the practicality. You would require really good temperature control and to be able to hold it for long enough for your
fraction to settle -- or else have some means for filtering without altering the tempertature significantly.
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Fulmen
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Still, it's worth a shot. I would think you'd need a vessel with: insulation -> temperature regulation -> thermal mass -> sample.
The upside is that it should be completely safe to run it unattended for long periods.
We're not banging rocks together here. We know how to put a man back together.
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Morgan
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There's a pdf entitled "Crystallization Behavior of Waxes" on Google that has some thoughts/approaches. Having a passing interest in electrets, it
crossed my mind maybe a purified fraction of carnuba wax and beeswax would have enhanced electrostatic properties.
CRYSTALLIZATION BEHAVIOR OF WAXES
https://www.google.com/url?sa=t&source=web&rct=j&...
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SWIM
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If I were going to try separating Paraffin components I'd probably look into finding an appropriate solvent to thin the mixture so it would separate
at a lower temperature.
Mixtures where the components are very similar sometimes don't separate on cooling very well.
Some essential oil mixtures just gel or solidify without separation unless you thin them a bit with an appropriate solvent.
I suspect a mixture of even more similar components like Paraffin might be even worse in that regard.
There's also the possibility of separating the straight from the branched chain alkanes by using urea inclusion complexes.
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