uchiacon - 3-9-2011 at 13:40
Hey guys,
I recently got about 5L of molecular sieve from a solvent recycling place for free, and I was just wondering what the capabilities of these sieves
are?
Among drying out ethanol(it's a water absorbing sieve), I was thinking that it might be possible to circumvent the whole h2so4 distillation process
for concentrating 70% nitric, and simply use this sieve to absorb most of the water.
Provided the sieve won't absorb the nitric acid molecules, (it's carbon molecular sieve btw), and that it won't react with the nitric, could this
work? Will I have to distill it anyway, as opposed to just decanting off the nitric and leaving the beads?
SmashGlass - 10-10-2011 at 07:52
You'd have to know which type of mol. sieve you have first and
whether they are "activated". A good way to test this is put a
bit of spit in the palm of your hand (preferably your own) and
add one mol sieve to it. Crude but generally an effective
indicator test. It should get hot if it reasonably activated. If it
only warm-ish it not that great, but will absorb some moisture
from solvents.
The pore size defines which solvents it is most suited for. 4Å is
good for DMF, pyridine, dioxane, ether or chemical reactions. 3Å
is better for methanol or ethanol. 5Å toluene and xylene. I've
never tried to put mol. sieves in mineral acids, so unsure on the
effects there.
On can reactivate mol. sieves but it is useful to know which
solvent has been in there before since most are toxic, smelly
and flammable. You need a good vacuum pump though.
Good luck