Sciencemadness Discussion Board - Best Drying Agent for MeOH

Best Drying Agent for MeOH

rocket_psyance - 12-6-2010 at 14:30

After UTSE, website#1 specifically states that Magnesium and Magnesium Oxide are good drying agents for alcohols... but for Magnesium Sulfate it states: "Almost all compounds including acids, acid derivatives, aldehydes and ketones".

Website#2 recommends "anhydrous magnesium or calcium sulphate" for alcohols.

Why doesn't website#1 just say "Alcohols" instead of "Almost all compounds..."? Why is there any discrepancy at all?

Is dumping MgSO4 into an old gallon of MeOH the best OTC solution for drying and/or long-term storage?

Chainhit222 - 12-6-2010 at 15:07

Quote: Originally posted by rocket_psyance

After UTSE, website#1 specifically states that Magnesium and Magnesium Oxide are good drying agents for alcohols... but for Magnesium Sulfate it states: "Almost all compounds including acids, acid derivatives, aldehydes and ketones".

Website#2 recommends "anhydrous magnesium or calcium sulphate" for alcohols.

Why doesn't website#1 just say "Alcohols" instead of "Almost all compounds..."? Why is there any discrepancy at all?

Is dumping MgSO4 into an old gallon of MeOH the best OTC solution for drying and/or long-term storage?

MgSO4 will work for MeOH.

franklyn - 12-6-2010 at 15:32

What do you think this is , physics ?
You expect coherency from chemistry ?

The point to remember when choosing a drying agent
is to pick the one which has the least solubility when
filtered cold.

Yes MgSO4 works and is cheap OTC, if you don't mind distilling
to be rid of the trace residue.

Attached is more than even you want to know.

.

Attachment: Drying of Solvents.zip (1.6MB)
This file has been downloaded 989 times

peach - 14-7-2010 at 03:24

CLICK THIS

Sometimes it's just how you phrase something that better plunders a google tresh-ar

I'd like some of them thar molecular sieves myself

[Edited on 14-7-2010 by peach]

soul_clothes - 27-7-2010 at 09:55

Well I had some old methanol lying around so I threw in some mag sulfate just to keep it dry. The liter-or-so has been sitting for a couple days now but(the container is opaque so I'm guessing here) the meoh looks milky-cloudy and it appears that not all the mgso4 has settled.

Can it be filtered, or must it be distilled to remove the fine mgso4 particles?

If it must be distilled then maybe mgso4 is not the best drying agent?

The WiZard is In - 27-7-2010 at 10:58

Quote: Originally posted by rocket_psyance

---------
Try Brauer's Handbook of Preparative Inorganic Chemistry,
p 26. I believe it dobe int the Sci Mad library.

djh
----
The average women would rather have
beauty than brains because the average
man can see better than he can think.

Anon.

SWilkin676 - 29-7-2010 at 07:52

<<I'd like some of them thar molecular sieves myself>>

They ain't what they're all cracked up to be. We bought some 3a in bulk and it has a problem in that it deposits white dust in whatever you use it in so you wind up having to distill it to get it out - or filter with diamateous earth.

rrkss - 29-7-2010 at 07:57

Quote: Originally posted by SWilkin676

<<I'd like some of them thar molecular sieves myself>>

They ain't what they're all cracked up to be. We bought some 3a in bulk and it has a problem in that it deposits white dust in whatever you use it in so you wind up having to distill it to get it out - or filter with diamateous earth.

That is true. Everytime I use my 3A to make anhydrous ether or ethanol, I have to distill before I use and it coats the distillation flask with a white layer which takes some scrubbing to remove.

How about Diatomaceous Earth?

turkey_baser - 21-5-2012 at 07:54

It's supposedly inert, so why not create layers of filter paper, DE, filter paper, DE etc...?

I was thinking about being lazy and just filtering gas line meoh several times if you don't feel like distilling a bunch of meoh...

Wadya think?