Natural Science Forum / Chemistry / Organic Synthesis / September 2003

Magnesium sulfate won't work cause it will partially dissolve in the alcohol
AND it also reacts with alcohol.

The easiest way to dry ethanol:

1.  Take 1 L of 95% ethanol and add 20 g of magnesium turnings.
2.  Start heating.  The alcohol starts to react with the magnesium,
producing hydrogen and magnesium ethoxide.  If it doesn't start, shoot in a
0.5 mL of chloroform, then keeping heating.
3.  Gently reflux the mixture until all the magnesium has been consumed
(1 -2 hours).
4.  Distill the mixture, discarding the fore and after run.

Dave

"Dave Muzuno" <nobody@nowhere.com

--------
Organic Synthesis, Collective  Volume 1 pg. 249.

Suggests (if  the presence of methyl alcohol is permissible):-

"by dissolving 24g of magnesium turning in 200 cc. of absolute methyl alcohol (the
reaction is vigorous) and then adding 3 l of the ordinary grade of absolute
alcohol (about 99.5 per cent). The mixture is refluxed for about 5 hours
and distilled into a flask in which the absolute alcohol is to be used."

Preparation using sodium and chlorform can be found on page 259 (same volume).

--
donald j haarmann - independently dubious

Dave Muzuno a écrit dans le message ...

alcohol

If your alcohol is around 95% distilling through a column filled with corn
meal  will remove most of the water.  NaCl (rock salt )  will remove traces.
CaO can be mixed
with the alcohol and then near absolute alcohol removed by distillation.  Of
interest  is this site.
http://www.journeytoforever.org/biofuel_library/ethanol_manual/manual_ToC.ht
ml

James

traces.

Of

I've had a quick look at the web site above (ethanol manual) and there is a
lot of incorrect stuff there (as with most web sites!).
The rock salt thing won't work, (a) you simply can't get enough water out of
the ethanol that way (b) salt is slightly soluble in ethanol (esp wet
ethanol) and I don't think salt in your fuel tank - even traces - is a good
idea. I don't know where the corn meal column is coming from either - it
won't absorb enough water, and you can't distill out the last 5% water so
I'm not sure of the logic behind it.

Barry Hunt

in a

alcohol (the

absolute

<snip>
this is cheating, Donald, you're starting with 99.5% ethanol!

Barry Hunt

Barry Hunt a écrit dans le message ...

in

corn

t

of

If one starts with 95% EtOH distilling through a dry corn meal
column will remove almost all of the water
NaCl is not soluble in near absolute alcohol and will remove the traces just
fine.
Would you like to point out the errors you found in the link I gave?

James

wouldnt it be possible to add anhydrous copper sulfate, then filter
then distill.  I dont believe the copper sulfate reacts with ethanol
and if there were any dissolved in the alcohol after this it could be
tested for either visually or with a spectrometer (the blue tint
rather than no tint present from the magnesium sulfate).

I've never had much success drying alcohols (ethanol?) or other polar
solvents with salts, so I don't hold out much hope that you will be
able to do so using CuSO4.

Also, don't rely on a lack of color as an indicator that you have not
contaminated your alcohol with the salt. Remember, the color is due to
the water of hydration. If that water is removed, CuSO4 is colorless.
It is possible to have a minute amt of the salt in the solvent and,
because it is dehydrated, have no color from it.

Steve Chaffin

firmabs6pk@sexmagnet.com (FirmAbs6pk) wrote in message news:<bii9qg$c2d@panther.Gsu.EDU>...

A symple method from 95° EtOH is destil with CaO

--
"La sintesi organica è la chimica che fa Dio quando ha voglia di divertirsi
un po'. Se Dio è un chimico" (A.R.)

______________
Albert Ruggi
a.ruggi@inwind.it
www.chimicavita.cjb.net
"Michael Carpenter"