feacetech - 17-4-2007 at 15:52
Which is the best desiccant for use in a desicator
High-Absorption Desiccant/Purifier; alumina silicate
http://www.coleparmer.com/Catalog/product_view.asp?sku=24450...
Drierite desiccants; anhydrous calcium sulfate
http://www.coleparmer.com/Catalog/product_view.asp?sku=07193...
Well I think the high aborbtion looks to irritating to handle, it says on th msds that it must be dried one layer thick and it can be destroyed from
over heating.
Anyone used the high absorbtion, is it easier to dry than what they say can it be dried in an air oven at 101 C in glass beakers or do you have to do
as instructed.
[Edited on 18-4-2007 by feacetech]
[Edited on 18-4-2007 by feacetech]
Klute - 18-4-2007 at 10:19
Depending on what you want to dry, high absorbtion silicates are really not necessarry, the much more common CaCl2 is quite effecient and
cheap/available everywhere... Solid NaOH/KOH workes very well, so as conc.H2SO4 although you should not use a base to dry a possibly volatil acid,
and vice versa or the vapors could react... IIRC, CaSO4 is a very effecient drier in the sense that is will really remove the last bit of water in
most solvants and in the air, etc, but has a weak absorbtion capacity, you need alot if not using another dissicant to get the stuff already nicely
dried...you could just aswell gets ome NaOH or CaCl2 from your local hardware shop, Silica gel works nice and is regenerable nearly infinitly,if you
can get it cheap locally, or making it from sodium silicate and acid is very easy as you won't need very pur form for dissicants. Just pop it in the
oven for an hour or two at 150°c, and it's as new. All of these will be much less expensive in hardware shops, etc. Although KOH can sometimes be a
little expensive. I would suggest keeping your money for other things 
The most common dissicant I've seen in labs is the drierite, i guess it's the cheapest.
[Edited on 18-4-2007 by Klute]
[Edited on 18-4-2007 by Klute]
Nerro - 18-4-2007 at 12:01
If you want it to be really dry you might consider something that really reacts irreversibly with water, like K2O, Na2O, CaO or P4O10.
Klute - 19-4-2007 at 13:11
I was quite deceived from CaO use in a dessicator, although it was from a gardening supply, not slacked lime. I guess alot of it must have already
turned to Ca(OH)2 or simply contain contained other salts or such. It worked for drying alcohol by refluxing and distilling though.