Azarius (Stranger)
04-14-02 19:00
No 296835
      powdered KOH dehydration  Bookmark   

Can powdered KOH bee dehydrated to remove the atmospheric water it picked up while being powdered simply by heating in an oven @175C, or would this drastically increase K2CO3 content?

Many thanks,
Azarius
 
 
 
 
    hest
(Hive Bee)
04-14-02 19:14
No 296838
      It's posible to dehydrate KOH in an owen (dont' ...  Bookmark   

It's posible to dehydrate KOH in an owen (dont' let it melt)
It will pick some CO2 up from the air, but not that much (there is only 200-300ppm to take)
 
 
 
 
    Elementary
(Hive Addict)
04-14-02 19:25
No 296839
      KOH Hydrates  Bookmark   

KOH.(H2O)x

x=4 MP -32.7C
x=2 MP 35.5C
x=1.5 and 1 MP 143C

(Pickering, J.C.S., 1893, 63, 890)

At about 200C I can't really see much more than small amounts of Carbonate forming.

If you are really bothered by small amounts of carbonate, heat the KOH in an inert atmosphere/vacuum, or heat the KOH higher than 1000C to rid the CO2

Nobodys home
 
 
 
 
    terbium
(Old P2P Cook)
04-14-02 20:08
No 296850
      But why?  Bookmark   

Can powdered KOH bee dehydrated to remove the atmospheric water it picked up while being powdered
But if the powdered KOH is being used to isomerize an allylbenzene then is this necessary?
 
 
 
 
    Aurelius
(Hive Bee)
04-14-02 23:00
No 296897
      necessity of drying  Bookmark   

Terbium, aurelius wasn't sure if that was retorical.  So... no, it doesn't need to be dried.  it is preferred that no visible water is present, but the minute traces make almost no difference in the course/yeild of the isomerization.  (from practical experience)
 
 
 
 
    Azarius
(Stranger)
04-15-02 01:47
No 296950
      k, thanx ppl :)  Bookmark   

k, thanx ppl :)