evil_lurker
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Posts: 767
Registered: 12-3-2005
Location: United States of Elbonia
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Mood: On the wagon again.
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Ether synthesis run... weird things happened.
I was outta concentrated sulfuric acid so I decided to use some anhydrous EtHSO4 that I made many moons ago according to the US3024263 patent.
113 parts by weight of sodium bisulfate and 20 parts by weight of pure grain alcohol are combined in a flask and brought to boiling upon which
time the sodium bisulfate crystals disappear and sodium sulfate forms.
When the reaction has been completed, the flask was is immersed in an ice bath and vigorously stirred until the tempurature rapidly goes below 32.3C.
The formed sodium sulfate is thus filtered out leaving an anhydrous ethyl hydrogen sulfate/ethanol mix.
The plan was to heat about 400ml of the ETHSO4 up to 140C, then add in EtOH, however, it didn't quite work that way. Around 100C, it started to
boil... and to my surprise make ether. Boiling was continued for approx 2.5h until I ran outta ice. The temp was at 120C when heating was stopped.
During this time about 100ml or so of ether was collected and the top of the 300mm hempel column got warm, but still cool enough to wrap your hand
around. I guess this does make sense if there was any free water or alcohol in the starting EtHSO4, however the temperature at which it occurred was
what got me.
The reaction for ether is:
EtHSO4 + EtOH = Et2O + H2O + H2SO4
H2SO4 +EtOH = EtHSO4 + H2O
And the chain continues until the EtHSO4 loses its capability to make more ether due to the equalibrium shift caused by water formation. By using a
good reflux column, preferably at least a 300mm vigreux, I believe the process could be greatly improved over the "classic" ether formation using
1mole of alcohol, 1 mole of sulfuric acid, and 1 mole of of alcohol run into the former.
At the end of the ether formation, one could simply boil another mole of NaHSO4 + EtOH and add it to the cooled EtSO4 in effect regenerating its ether
production capability.
I'm going to do some more testing today, and make about 600ml of 1:1 EtOH/EtHSO4 and see what it'll do.
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starman
Hazard to Others
Posts: 318
Registered: 5-7-2008
Location: Western Australia
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Mood: No Mood
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Quote: Originally posted by evil_lurker  | I was outta concentrated sulfuric acid so I decided to use some anhydrous EtHSO4 that I made many moons ago according to the US3024263 patent.
113 parts by weight of sodium bisulfate and 20 parts by weight of pure grain alcohol are combined in a flask and brought to boiling upon which
time the sodium bisulfate crystals disappear and sodium sulfate forms.
When the reaction has been completed, the flask was is immersed in an ice bath and vigorously stirred until the tempurature rapidly goes below 32.3C.
The formed sodium sulfate is thus filtered out leaving an anhydrous ethyl hydrogen sulfate/ethanol mix.
The plan was to heat about 400ml of the ETHSO4 up to 140C, then add in EtOH, however, it didn't quite work that way. Around 100C, it started to
boil... and to my surprise make ether. Boiling was continued for approx 2.5h until I ran outta ice. The temp was at 120C when heating was stopped.
During this time about 100ml or so of ether was collected and the top of the 300mm hempel column got warm, but still cool enough to wrap your hand
around. I guess this does make sense if there was any free water or alcohol in the starting EtHSO4, however the temperature at which it occurred was
what got me.
The reaction for ether is:
EtHSO4 + EtOH = Et2O + H2O + H2SO4
H2SO4 +EtOH = EtHSO4 + H2O
And the chain continues until the EtHSO4 loses its capability to make more ether due to the equalibrium shift caused by water formation. By using a
good reflux column, preferably at least a 300mm vigreux, I believe the process could be greatly improved over the "classic" ether formation using
1mole of alcohol, 1 mole of sulfuric acid, and 1 mole of of alcohol run into the former.
At the end of the ether formation, one could simply boil another mole of NaHSO4 + EtOH and add it to the cooled EtSO4 in effect regenerating its ether
production capability.
I'm going to do some more testing today, and make about 600ml of 1:1 EtOH/EtHSO4 and see what it'll do. |
I am reviving this old thread because I think there is some merit into looking at this reaction for optimisation of ether production.
I did U2U evil lurker to see how he went with further experimentation but he hasn't visited the site for a while.
I also attempted the conditions of the patent which is mentioned in several other threads in connection with the manufacture of diethyl sulfate.The
slurry(if you can call it that-more like a crust that sits atop the refluxing ethanol) was impossible with a magnetic stirbar(migrated to the top of
the mixture). The patent states that the refluxing solvent provides sufficient agitation but at the ratio of 20g/113g its a pretty dry mix with not
much agitation going on.
Anyway.I refluxed about an hour.Did not notice the appearance of "needle like" Na2SO4 (still looked like granular NaHSO4 to me) but the fluid
component took on a dark brown oily appearance.Upon cooling down and disassembly I was greeted by penetratrating ethereal odour with no hint of the
starting ethanol aroma.(perhaps this was simply masked)
So questions are.
Is thermal decomposition of "anhydrous" NaHSO4 with no added EtOH going to produce Et2O? this would by my calculation leave oleum in the pot and
dosen't seem terribly likely.
Given the increasing difficulty of obtaining (in Oz) H2SO4 and the easy availability and low cost of bisulfate I am curious as to whether this can be
set up as a continous process analogous to the standard dehydration reaction with H2SO4 without necessarily isolating the ethyl hydrogen sufate.
Chemistry- The journey from the end of physics to the beginning of life.(starman)
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