FriendlyFinger (Newbee)
10-27-01 01:28
No 229257
      Isopropyl alcohol with Mg SO4  Bookmark   

Hi there,

Recently, I accidently put a heaped tea spoon of  super anhydrous MgSO4 in 100ml of anhydrous analytical grade Isopropyl alcohol. The alcohol was straight from the mother bottle.

The solution went cloudy, put in the freezer,  and stayed cloudy for days and days. Then the MgSO4 sunk and the solution turned crystal clear. Why did it take so long? 

Kind regards,
(Distinctive Doe)
10-27-01 03:11
No 229261
      Re: Isopropyl alcohol with Mg SO4  Bookmark   

Suspended particles due to the solution viscosity.  Anhydrous isopropyl alcohol is actually a fairly viscous fluid, compared to methanol or acetone.  I noticed the same exact thing when drying with Na2SO4.  Particles stay suspended for a while.  When drying acetone this did not occur.
Filter it, that clears the solution right up.  A coffee filter should work fine.

The freezer probably slowed down the settling.  If the bottle is sealed tight there is no reason to put it in the freezer.

Do Your Part To Win The War
(Hive Bee)
10-27-01 07:35
No 229282
      Re: Isopropyl alcohol with Mg SO4  Bookmark   

MgSO4-dust can be hell to filter out (goes right through coffee filters anyway).
Better use chunks to dry. The drying takes a little longer but the chunks are much easier to remove than powder.

Hansje high in proteine and fibre!
(Distinctive Doe)
10-27-01 08:34
No 229296
      Re: Isopropyl alcohol with Mg SO4  Bookmark   

Ok then no coffee filters.  A nice big buchner funnel hooked up to the aspirator is how I did it.

Do Your Part To Win The War
10-27-01 23:40
No 229493
      Re: Isopropyl alcohol with Mg SO4  Bookmark   

Thanks guys.

That sure clears things up in my mind as well as my solution.
I've only used coffee filters once. Then I discovered WHATMAN, went to a few auctions and now I have every grade of filter under the sun. All at a very modest price!

Kind regards