Magpie - 14-11-2015 at 19:11
This is a gaseous reagent I have wanted to obtain for a long time. Ideally I would like to have a compressed gas cylinder like hospitals use but that
doesn't seem likely. So I'm looking for a way to make a dry, controlled, stream of EtO myself.
Wiki shows this synthetic method:
I-CH2-CH2-I + Ag2O --> (CH2)2O + 2AgI
from a book in Russian, "Khimiya." I am looking for this reference and and an English translation of this synthesis. This appears to be a
solid-solid reaction that produces anhydrous EtO.
Crowfjord has offered this paper, linked in References, which may give me the information I need:
"A general integrated process for synthesizing olefin oxides"
I'm hoping 1,2-dibromoethane could be used instead as it would likely be more stable, cheaper, and easier to make.
Comments, suggestion, and questions are encouraged.
Waffles SS - 14-11-2015 at 19:57
I did some reaction with EO.That is really nasty and dangerous stuff(be careful)
I attached reaxys search of all possible way for synthesis of EO(hope this help you)
Attachment: EO.pdf (937kB)
This file has been downloaded 901 times
[Edited on 15-11-2015 by Waffles SS]
Magpie - 14-11-2015 at 20:30
Yes, thanks Waffles. I'll look that material over. I know it is nasty and wouldn't think of making it without a good fume hood.
I looked over the Sun et al paper from Crowfjord. The conversion for the Ag2O + 1,2-dibromoethane reaction is low at ~10%. Also this was done in a
slurry with water so is not anhydrous.
Maybe I need to accept the fact that I would have to dry the EtO. I don't know off-hand what drying agents might be acceptable, eg, H2SO4, KOH, mole
sieves, etc.
S.C. Wack - 15-11-2015 at 18:07
Weygand recommends 2-chloroethyl acetate "added dropwise to a mixture of coarsely ground potassium hydroxide and sand. The ethylene oxide generated is
dried by passing it over freshly ignited soda-lime"... leading to one not-English reference and then even more for the precursor and its precursors,
such as starting here at the very end of the relevant Watts Dictionary page
https://books.google.com/books?id=Wt3nAAAAMAAJ&pg=PA61
Magpie - 15-11-2015 at 20:42
Interesting, but the 2-chloroethylacetate may be hard to come by. I see that Sigma wants $50/g for it which may be an indication of its either its
low demand, or difficult synthesis, or both.
I see in OrgSyn also that soda-lime is specified for EtO drying.
AvBaeyer - 15-11-2015 at 20:49
Magpie,
Do you really need ethylene oxide (EO) for a particular purpose? There are work-arounds that essentially give you products derived directly from EO. I
am referring to organic synthesis methods.
Like Waffles, I have worked with EO and found it to be non-forgiving in many organic reactions. Lots of polymers.
Just my two cents.
AvB
Magpie - 15-11-2015 at 21:11
I wanted to use it for making primary alcohols via Grignard.
AvBaeyer - 16-11-2015 at 18:56
Ethylene oxide does work ok for 2-carbon homologation like you want to do. Careful control of the Grignard addition, particularly temperature of the
reaction, is needed to prevent polymerization. If you do make EO, you might consider trapping it directly in THF and then use that solution in your
Grignard reaction. You could determine EO concentration in the THF by weight change.
As for 2-chloroethyl acetate, it can be easily made from 2-chloroethanol and acetic anhydride. I have purchased in the past 2-chloroethanol from
legitimate sources at pretty reasonable cost.
AvB
Magpie - 16-11-2015 at 19:30
Thanks for that information. Have you ever made EtO form 2-chloroethanol? garage chemist mentions this but I don't know if he ever posted a
synthesis. Sometimes he posted only on versuchschemie.de, but I can't access that now. Pok's links don't work for me.
Waffles SS - 16-11-2015 at 21:32
https://www.youtube.com/watch?v=bKiXxoRZ_VQ
http://www.sciencemadness.org/talk/viewthread.php?tid=12607
(good information on page 2)
Also i attached the reaxys search of all possible way for synthesis 2-Chloroethanol
Attachment: 2-Chloroethanol.pdf (653kB)
This file has been downloaded 1267 times
Magpie - 17-11-2015 at 09:50
Yes, that is where I read garage chemist's comments. I would like to search versuchschemie.de to see if he gave his synthesis.
I would like to make a comparison between the 2-chloroethanol (ethylene chlorohydrin) method and the method using 2-chloroethyl acetate.
AvBaeyer - 17-11-2015 at 18:01
Magpie,
I never made ethylene oxide. I always bought it in lecture bottles and made up working solutions in THF. Ah, the good old days!
Getting your hands on 2-chloroethanol may be more difficult now than a couple of years ago when I bought mine. I cannot find it openly listed any
longer. You can buy chloroacetic acid from Elemental Scientific. This can be converted to the methyl or ethyl ester then reduced with sodium
borohydride to 2-chloroethanol. You do not need lithium aluminum hydride to do this reduction. (I have actually just finished a small project reducing
several esters to alcohols with NaBH4.)
AvB