weiming1998
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Bisulfate+ethanol: Success?
I know that this topic has been discussed before, but (I think) this is the first time somebody has done it (somewhat) successfully.
A few hundred grams of NaHSO4 is added to a beaker. 400mls of ethanol (methylated spirits) is added. The beaker is heated up. There was an evolution
of a thick vapour that didn't look like vaporized alcohol. The mix is then cooled and rested for a day. A day later, the ethanol (which is now yellow)
is poured off and boiled in the beaker again, minus the bisulfate. The mix was getting darker and darker in colour, and begun to bubble more slowly.
Finally, there was only a few lazy bubbles bubbling. The mix has begun to fume.
The vapours formed smelt nothing like ethanol, more like SO2, and irritates my eyes. At this point I turned off the flame. The mix dissolves iron
slowly when heated, but very rapidly when cooled. Some is poured on homemade potassium chlorate. It didn't react (probably because the chlorate was
too impure. Then some is dipped on sugar through a syringe. Now, the interesting thing is that the sugar didn't react, but when I dripped ethanol on
the and lit the pile, it (very rapidly) bubbles and carbonizes , instead of charring, like what a normal flame would have done.
What kind of sulfuric acid rapidly carbonizes something only when burnt? Also, why does it dissolve iron more quickly cold than hot? Is it
passivation? Any help would be appreciated.
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AJKOER
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Now as H2SO4 will dehydrate Ethanol:
2 C2H5OH ====> C2H5OC2H5 + H2O
140 deg
upon substituting NaHSO4 for H2SO4 assuming its similarly dehydrates as:
NaHSO4 + H2O <===> NaOH + H2SO4
then:
2 C2H5OH ====> C2H5OC2H5 + H2O
x deg
or diethyl ether which is colorless and boils at 34.6 C. This is my best guess as I am not much of an organic chemist.
Per wiki:
"Ethanol is mixed with a strong acid, typically sulfuric acid, H2SO4. The acid dissociates in the aqueous environment producing hydronium ions, H3O+.
A hydrogen ion protonates the electronegative oxygen atom of the ethanol, giving the ethanol molecule a positive charge:
CH3CH2OH + H3O+ → CH3CH2OH2+ + H2O
A nucleophilic oxygen atom of unprotonated ethanol displaces a water molecule from the protonated (electrophilic) ethanol molecule, producing water, a
hydrogen ion and diethyl ether.
CH3CH2OH2+ + CH3CH2OH → H2O + H+ + CH3CH2OCH2CH3
This reaction must be carried out at temperatures lower than 150 °C in order to ensure that an elimination product (ethylene) is not a product of the
reaction. At higher temperatures, ethanol will dehydrate to form ethylene. The reaction to make diethyl ether is reversible, so eventually an
equilibrium between reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture
before it reverts to ethanol, taking advantage of Le Chatelier's principle."
[Edited on 2-2-2012 by AJKOER]
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entropy51
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Quote: Originally posted by weiming1998  | I know that this topic has been discussed before, but (I think) this is the first time somebody has done it (somewhat) successfully.
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Pardon my ignorance, but what were you trying to make that you think you suceeded at? Sulfuric acid? Or
what?
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weiming1998
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| Quote: Originally posted by entropy51 | | Quote: Originally posted by weiming1998 | I know that this topic has been discussed before, but (I think) this is the first time somebody has done it (somewhat) successfully.
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Pardon my ignorance, but what were you trying to make that you think you suceeded at? Sulfuric acid? Or
what? |
I think I succeeded at making sulfuric acid from NaHSO4+ethanol, but I might not. Still, I looked at this topic with the search engine. It didn't have
any relevant results. The few results were only extremely vague mentions about the subject without telling the exact details or success/failure.
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weiming1998
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| Quote: Originally posted by AJKOER | Now as H2SO4 will dehydrate Ethanol:
2 C2H5OH ====> C2H5OC2H5 + H2O
140 deg
upon substituting NaHSO4 for H2SO4 assuming its similarly dehydrates as:
NaHSO4 + H2O <===> NaOH + H2SO4
then:
2 C2H5OH ====> C2H5OC2H5 + H2O
x deg
or diethyl ether which is colorless and boils at 34.6 C. This is my best guess as I am not much of an organic chemist.
Per wiki:
"Ethanol is mixed with a strong acid, typically sulfuric acid, H2SO4. The acid dissociates in the aqueous environment producing hydronium ions, H3O+.
A hydrogen ion protonates the electronegative oxygen atom of the ethanol, giving the ethanol molecule a positive charge:
CH3CH2OH + H3O+ → CH3CH2OH2+ + H2O
A nucleophilic oxygen atom of unprotonated ethanol displaces a water molecule from the protonated (electrophilic) ethanol molecule, producing water, a
hydrogen ion and diethyl ether.
CH3CH2OH2+ + CH3CH2OH → H2O + H+ + CH3CH2OCH2CH3
This reaction must be carried out at temperatures lower than 150 °C in order to ensure that an elimination product (ethylene) is not a product of the
reaction. At higher temperatures, ethanol will dehydrate to form ethylene. The reaction to make diethyl ether is reversible, so eventually an
equilibrium between reactants and products is achieved. Getting a good yield of ether requires that ether be distilled out of the reaction mixture
before it reverts to ethanol, taking advantage of Le Chatelier's principle."
[Edited on 2-2-2012 by AJKOER] |
The reaction is done at the boiling point of ethanol, which is 78 degrees celsius, not 140 degrees (sulfuric doesn't form azeotropes with ethanol, it
simply forms ethyl sulfate. When the ethanol is boiled away, the ethyl sulfate decomposes at 200 degrees to ethylene and sulfuric acid. That explains
the fumes, but it could be still diethyl ether. If ethyl sulfate forms an azeotrope with ethanol, then the vapours were diethyl ether and the
corrosive effect on iron and carbonizing effect on sugar were caused by ethyl sulfate.
Anyway, I googled and found this http://en.wikipedia.org/wiki/Talk%3ASodium_bisulfate. It talks about being able to increase the speed of bisulfate+ethanol reaction. Does any of
you people know, under what conditions, will the reaction increase in speed? Anhydrous bisulfate or solution? Cold temp or hot? Water in ethanol or no
water?
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weiming1998
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No, the liquid was ethyl sulfate because when I mixed it ethanol and ignited it, it started bubbling and a white smoke,which is highly flammable
bubbled out. The white smoke fuelled the fire for several minutes. The ethyl sulfate, which would have decomposed into sulfuric acid and ethylene in
the fire. The ethylene fuels the fire while the sulfuric acid reacts with ethanol, creating more ethanol sulfate and diethyl ether. But eventually the
liquid stops burning. I guess that's when the different products are at an equilibrium with each other.
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