Author Topic: drying ether  (Read 2078 times)

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acx01b

  • Guest
drying ether
« on: October 23, 2004, 01:53:00 AM »
hi what is the best way do dry C2H5-O-C2H5 ?
i purpose this: 30% H2So4 is boiled to get 50% H2SO4
50% H2SO4 (5ml) is added to 50ml of ether,
phases are mixed well.
ether layer is separated, and 0.5gram magnesium turnings are added, mixed well...

i purpose that the % of H2O will be 0.1% maximum.

Novice

  • Guest
Dry Et2O using elemental alkali
« Reply #1 on: October 23, 2004, 03:35:00 AM »
If MgSO4-dried ether isn't good enough for you, use either magnesium-, litium- or sodium turnings and stirring, then, when from what you can tell all the water present in the Et2O has reacted, distill the ether.

Adding 50% H2SO4 will only make it worse than it already is.

acx01b

  • Guest
nope mf, magnesium turnings wont dry it at...
« Reply #2 on: October 23, 2004, 05:30:00 PM »
MgSO4 dried ether is not dried: it still reacts with Na then...

nope mf, magnesium turnings wont dry it at all, maybe iodine + magnesium turnings but how to separate iodine from ether then ?

maybe by reacting iodine with MgO obtained by burning magnesium turnings... or any oxyde like CuO or something...

but iodine is not cheap, and instead of using iodine why not use sodium.. whereas my post was how to dry ether without NaH NaO Na NaNH2...

what about the electrolysis of melted NaOH ? is it hard to produce Na (inert gaz needed because Na melted reacts violently with O2 in air)
what about using desoxygenated Air (O2 --> CO2) as the inert gaz ?

cya

indole_amine

  • Guest
mol sieves
« Reply #3 on: October 24, 2004, 04:14:00 AM »
Molecular sieves. Residual water is 0.0001 percent by volume - "Analytical grade" water absence... :)


indole_amine

acx01b

  • Guest
Just to say (i learnt it today) that Conc.
« Reply #4 on: October 28, 2004, 02:58:00 AM »
Just to say (i learnt it today) that Conc. sulphuric acid won't work to dry ether by only mixing the 2 at room temp... for the simple reason that ether and conc sulphuric acid (80% i tried) have good miscibility together!

Novice

  • Guest
80% sulphuric acid contains more water than...
« Reply #5 on: October 28, 2004, 03:24:00 AM »
80% sulphuric acid contains more water than it contains sulphuric acid, which is to say, it won't react with any additional water.

There is only H2O, HSO4- and H3O+ in it, and as far as I know HSO4- isn't that strong an acid. At least not strong enough to bind the reast of the water.

If 80% sulphuric acid would work to dry ether with, it wouldn't have mattered if they were miscible or not, as you still have to distill the ether when you're done (leaving H2SO4 and H2O behind).

acx01b

  • Guest
so close to have free H2SO4 in it!
« Reply #6 on: October 28, 2004, 05:53:00 AM »
so close to have free H2SO4 in it!
density of 80% h2SO4 : 1.7, in 1L of 80% H2SO4
1360grams of H2SO4 (13.87mol) and 340grams of H2O (18.8 mol)

I just calculated that since 85% H2SO4-water solution begins to have free H2SO4

Novice

  • Guest
CaO might work for drying ether, yes.
« Reply #7 on: October 28, 2004, 01:37:00 PM »
CaO might work for drying ether, yes. I don't think it's as effective as elemental alkali though. Just don't try and dry the sulphuric acid with CaO :-}