EverythingAl2O3
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Carbonate ester synthesis from urea?
I know that carbonate esters are typically made from the reaction of phosgene and alcohols. I don't exactly have the equipment to handle phosgene, but
think it would be fun to synthesize and play with them in grignard reactions and maybe an attempt to make polycarbonates (making my own glasses lenses
sounds like a fun long-term project).
Urea seems like the easiest OTC source of the carbonate structure. The biggest issue I see is that amides are more stable than esters so conversion
from amide to ester will be particularly difficult, and that water/hydroxide will ruin the reaction. I think that the use of sodium/potassium
methoxide in methanol (because methanol doesn't form an azeotrope with water it can be easily purified) and refluxed for a period of time (maybe 24
hours). I know n-butanol can do this at high temperature according to this paper at temps around 175-190C so I'm hoping alkoxides will help speed up
the reaction at lower temps.
I will be personally attempting this once I get some urea and sodium/potassium metal to make pure alkoxides. Will probably use nurdrages magnesium
reduction method for it. As an additional side project I might attempt to make a super efficient high boiling alcohol catalyst based on his previous
work to see if I can beat the 10 hours of borneol for generating sodium and see just how fast potassium can be made. And I will try to also capture
the NH3 and store it as NH4Cl cuz if I'm gonna work with useful nasty smelling chemicals by god I'm gonna make sure I don't have to smell them.
And now I have issued myself a huge challenge that I hope to be able to achieve being new to actual synthesis of chemicals.
Attachment: Carbamic Esters from Urea.pdf (356kB)
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njl
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As discussed in other threads, simple carbonate esters can be made simply from the alcohol and urea in moderate yields. I bet you could even
incorporate Al2O3 into the reaction if you look around enough. I have tried this reaction between methanol and urea. Fairly uneventful reaction, but
using such low boiling alcohols makes the reaction take ages. So maybe catalytic alkoxide would help. Point being, you don't need a bunch of sodium to
get this reaction to work.
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EverythingAl2O3
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| Quote: |
As discussed in other threads, simple carbonate esters can be made simply from the alcohol and urea in moderate yields. I bet you could even
incorporate Al2O3 into the reaction if you look around enough. I have tried this reaction between methanol and urea. Fairly uneventful reaction, but
using such low boiling alcohols makes the reaction take ages. So maybe catalytic alkoxide would help. Point being, you don't need a bunch of sodium to
get this reaction to work.
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You are right it looks like Al2O3 can be used. I'm not sure what preparation method of the y-Al2O3 needs to be used. I'll need to search through the
references. It seems to have low yields though.
Attachment: Synthesis of organic carbonates from alcoholysis.pdf (3.5MB)
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BromicAcid
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I did a few trials to make ethylene carbonate in a different life, the results looked promising but like most of my early work I focused more on the
synthesis than the workup:
http://www.sciencemadness.org/talk/viewthread.php?tid=2948
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