Keras
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Diethyl ether from chloroethane and sodium ethoxide
Apparently,
C2H5ONa + C2H5Cl → C2H5OC2H5 + NaCl
Has anyone ever attempted this? Sodium ethoxide can apparently be made from ethanol and sodium hydroxide, and chloroethane from ethanol and
concentrated hydrochloric acid.
Might be a less risky way than the usual dehydration of ethanol by sulphuric acid at 140 °C.
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Pumukli
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"Has anyone ever attempted this?"
A man called Mr. Williamson probably did. 
https://en.wikipedia.org/wiki/Williamson_ether_synthesis
Less risky but much more expensive!
Btw. I tried making sodium ethoxide from NaOH and ethanol, I got something, but the condensation reaction I intended to with it failed! It may only
mean that I'm inept in practical org. chem. though.
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Keras
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I know that :p I meant anyone out here
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clearly_not_atara
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Chloroethane is nowhere near as easy to make as you're making it sound. Ethyl bromide is relatively easy with hydrobromic acid.
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Keras
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I read that chloromethane could be made from ethanol and hydrochloric acid using zinc chloride as a catalyst. In that case, it would be enough to
dissolve some zinc into the HCl before adding the ethanol.
What about ethyl iodide?
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clearly_not_atara
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Ethyl iodide works fine. Primary and methyl chloroalkanes are difficult to generate with the Lucas reagent as an extended rxn at high temp is
required. Additionally, the low bp of EtCl makes it annoying to distill. Even isopropyl chloride is a technically demanding synth due to low bp.
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SWIM
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Ethyl bromide can also be made with sulfuric acid and sodium or potassium bromide.
This used to be a common lab synth for 1st year organics labs.
Check any old lab manual and you'll probably find a small scale version of that reaction.
The classic acid dehydration of ethanol really isn't bad to do though.
Ice water in condenser and ice cooled receiver in a well ventilated room with an electric heating source does the job with minimal odor.
I have done this in summertime in an apartment building without attracting attention.
Also, it only requires the cheapest of ingredients. H2SO4 drain cleaner and 90-95% ethanol gives good results and you get to save your fine chemicals
for other things.
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Keras
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Quote: Originally posted by clearly_not_atara  | | Ethyl iodide works fine. Primary and methyl chloroalkanes are difficult to generate with the Lucas reagent as an extended rxn at high temp is
required. Additionally, the low bp of EtCl makes it annoying to distill. Even isopropyl chloride is a technically demanding synth due to low bp.
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I’m a bit nonplussed here, because I expected precisely the fact that ethyl chloride has a low boiling point to be an advantage, as it would bubble
out of the solution of HCl and ethanol and could be condensed in an ice bath cooled flask. However, on the other hand, ethyl iodide has about the same
boiling point as ethanol, which would make it a pain to distill out – only liquid chromatography would be suitable at this point.
| Quote: Originally posted by SWIM | Ethyl bromide can also be made with sulfuric acid and sodium or potassium bromide.
This used to be a common lab synth for 1st year organics labs.
Check any old lab manual and you'll probably find a small scale version of that reaction. |
Interesting, I will check that out.
| Quote: Originally posted by SWIM | The classic acid dehydration of ethanol really isn't bad to do though. Ice water in condenser and ice cooled receiver in a well ventilated room with
an electric heating source does the job with minimal odor. I have done this in summertime in an apartment building without attracting attention.
Also, it only requires the cheapest of ingredients. H2SO4 drain cleaner and 90-95% ethanol gives good results and you get to save your fine chemicals
for other things. |
I have done it twice, and since I work in an old barn with one wall missing and a roof something like 20 m above ground, I’m not really that worried
about lack of ventilation. But I find the main problem to be the high temperature. At 130 °C, a lot of water, alcohol and sulphuric acid passes over
through the distillation apparatus, and the end product needs a lot of cleaning. Of course, this is not insuperable, but it’s just annoying to
redistill, then neutralise, then dehydrate, etc. And even then, I have a small bottle of thus made diethyl ether, in which I put some KOH flakes to
check peroxide formation. I thought it to be reasonably pure, but soon the KOH dissolved and transformed into a yellow glop, probably due to the
simultaneous presence of acetaldehyde.
At the end, I simply bought a liter of commercial anhydrous ether for my future Grignard reactions :p – that I will try to recycle as much as
possible.
[Edited on 31-5-2019 by Keras]
[Edited on 31-5-2019 by Keras]
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Ubya
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| Quote: Originally posted by Keras |
I read that chloromethane could be made from ethanol and hydrochloric acid using zinc chloride as a catalyst. In that case, it would be enough to
dissolve some zinc into the HCl before adding the ethanol.
What about ethyl iodide? |
HCl+ZnCl2+alcohol is at the base of the Lucas test to identify tertiary alcohols. This Reaction is very fast for tertiary alcohols because of the
carbonation stability, secondary alcohols react but much slower, primary alcohols are inert or need heating and long reaction times. Plus the zinc
chloride is equimolar with HCl, "some" is not enough
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feel free to correct my grammar, or any mistakes i make
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ErgoloidMesylate
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| Quote: Originally posted by Keras | Apparently,
C2H5ONa + C2H5Cl → C2H5OC2H5 + NaCl
Has anyone ever attempted this? Sodium ethoxide can apparently be made from ethanol and sodium hydroxide, and chloroethane from ethanol and
concentrated hydrochloric acid.
Might be a less risky way than the usual dehydration of ethanol by sulphuric acid at 140 °C. |
Sodium ethoxide and ethyl bromide at 55C.
If a solvent is desired, ethanol.
Cannula transfer and cannula filtering is used for lysergic synth Compressed air and remove co2
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Keras
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Geez, that is an old thread. I have more or less abandoned any idea of producing diethyl ether by Williamson synthesis. Much too wasteful in terms of
resources.
Does, however, the acid have to be sulphuric acid? I mean, I understand that using HCl or any halide acid is not possible because it would boil off
before the reaction even taking place. But what about phosphoric acid, which, by the way, is not oxidising, so should not produce any tar at the end
of the reaction?
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clearly_not_atara
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I don't believe it's necessary to use sulfuric acid. The mechanism certainly doesn't suggest it is. One advantage of sulfuric acid is that it's a
strong hydrogen bond donor and acceptor, so it reduces the tendency of ethanol to boil away.
Phosphoric acid may or may not be strong enough. pKa EtOH2+ ≈ -2.5 IIRC.
Toluenesulfonic acid is liquid at the relevant reaction temperature range. The formation of ethylene might also be a mechanism of tar formation. But
TsOH can be easier to handle for other reasons.
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Texium
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Thread Moved
5-5-2023 at 10:35 |
ErgoloidMesylate
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| Quote: Originally posted by Keras |
Geez, that is an old thread. I have more or less abandoned any idea of producing diethyl ether by Williamson synthesis. |
Don't take this personally, but this forum can be searched by anyone. It is for that info be readily available I typed it. I never believed or thought
you wanted to synth ether, as i have zero reason to think so.
Cannula transfer and cannula filtering is used for lysergic synth Compressed air and remove co2
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