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How to dry 96% enthanol to 100%

Migrated topic.
G

Garfield

Sascha
Hi Nexians,

A special to question to all the great chemists at the Nexus.
I need for a special conversion technique 100% ethanol, but only have 96%.:cry:
So my short question is:
Would it be possible to go the same route as for drying aceton, using anhydrous epsom salt?
Or do really have to use anhydrous coppersulfate.
I have both but would like to use epsom because of foodgrade purpose.

Every help is appreciated.

Garfield
 
Thank you very much for the quick answers.
I was just wondering because wikipedia and other sources stated that epsom is slightly soluble in ethanol, but nowhere appears a number for that. So I guess it´s soluble because of water residue in ethanol. :d

So thanks again, helped me to make my day brighter.:lol:

Garfield
 
I think that in this case, the cornmeal, straw or sawdust acts as the molecular sieve, as opposed to using zeolite - so all you would need is one of these, cornmeal probably being the easiest to get your hands on.
 
narmz said:
I think that in this case, the cornmeal, straw or sawdust acts as the molecular sieve, as opposed to using zeolite - so all you would need is one of these, cornmeal probably being the easiest to get your hands on.
Click to expand...
Am I getting something wrong here?
When I use a molekular sieve I´m supposed to use it the same way as epsom in aceton, just by throwing it into the solvent shake the hell out of it and let it settle.
Right?
If so and I use cornmeal etc. the fats and a lot of other stuff will dissolve into the ethanol.
When I´m using this ethanol for an isomerisation process, I have not the faintest idea how these residues will react with for example sulfuric acid.
Or am I wrong here?
 
i have used zeolite type 3a to dehydrate 95% ethanol. i used to have an alkohol meter, but no longer.:cry:

in the ethanol industry, perhaps half of the stuff in the usa is dehydrated with a modified corn grit. the stuff is packed into columns, and ethanol in VAPOR phase is passed thru to remove traces of water.

i know there are references to using corn grits, cellulose, etc on the internet, but i am not too sure how well they would work in liquid phase at room temp. i would be very curious to know, however.

without an alcohol meter, how can you really be sure?

i would have thought that magnesium sulfate would dissolve in the water in the ethanol. maybe try it, and evap some to look for mg residue. it seems to work for ipa.
 
biopsylo said:
i have used zeolite type 3a to dehydrate 95% ethanol. i used to have an alkohol meter, but no longer.:cry:

in the ethanol industry, perhaps half of the stuff in the usa is dehydrated with a modified corn grit. the stuff is packed into columns, and ethanol in VAPOR phase is passed thru to remove traces of water.

i know there are references to using corn grits, cellulose, etc on the internet, but i am not too sure how well they would work in liquid phase at room temp. i would be very curious to know, however.

without an alcohol meter, how can you really be sure?

i would have thought that magnesium sulfate would dissolve in the water in the ethanol. maybe try it, and evap some to look for mg residue. it seems to work for ipa.
Click to expand...
Thanks for clarification.:d
The 3 angstrom type is what I will order, and in addition a more precise alcohol meter. With my already existing one I have to guess everything above 98.5%. I once tested it with ultra pure 99.9% lab grade ethanol, and it showed me something like 103% :shock:

Doing it with corn grit in a column and ethanol in vapour phase makes sence to me, but I found a statement in the german wikipedia that it´s not in industrial use.
I will check for magnesium residues before doing my process. I will definitely add a lot more epsom than this would need, as I´m doing it with my aceton. Always on the save side.
 
molecular sieves won't do it either. to get absolute alcohol, you'd need to distill it in the presence of a compound which has predominantly VanDerWaals interactions like benzene, nothing that can potentially hydrogen-bond. even after fractional distillation of the recovered alcohol, it will contain traces of the nonpolar.

absolute ethanol is used in synthesis. for all practical purposes, grain alcohol is suitable
 
I'm surprised no-one has mentioned the magnesium/iodine method mentioned in Harwood and Moody's "Experimental Organic Chemistry". I could type up the method, I suppose.

The article about Molecular Sieves started with alcohol that was already markedly anhydrous. If you look at the data, the starting concentration of water was around 1200ppm - i.e. 0.12% - so that was 99.88% alcohol to start with.

Sounds like adding cornstarch, filtering and then redistilling in apparatus fitted with a drying tube, possibly followed by molecular sieves, might be the way to go.
 
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