RE: molecular sieves

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Before using a molecular sieve, you first have to determine which one to
use.  Type 3A if for unsaturated hydrocarbons and polar fluids.  These
would include methanol, ethanol, and acetone. The 3A refers to the size of
the molecule it can absorb.  In this case, less than 3 angstrom.  Molecular
sieve 3A has an absorption capacity of 22% by weight.

To dry liquids,  add a slight excess of drying agent to the liquid.  Next,
a little calculation. Call your vendor and retrieve a C of A (certificate
of analysis) for the lot of reagent you're using.  There should be a spec
for water content.  The water content value is the moisture in the bottle
upon release.  An open bottle would have higher moisture depending on how
hydroscopic the reagent is.   Let's use methanol which is very hygroscopic
as an example.  Let's say the C of A states the water content is 1.0% which
equates to 4 ml in a 4 liter bottle.  4 ml of  water is equal to 4 g of
          22%x (   )=  4g  = 18.18 g  for excess use 20g molecular sieve.
 Mix thoroughly and allow the liquid to stand.  After a few minutes,  the
drying agent settles to the bottom of the container.  Separation can be
completed by decanting or filtration (suction filtration would work best
and fastest ).

How often you would dry a solvent out is dependent on application, use, and

TIP: Depending on application and specifications required, the use of
molecular sieves may eliminate to need to purchase expensive super dry

If you have further question,  feel free to ask.

Rande Kline, HT (ASCP )& Joe Daniels
Technical Services
EM Science

"Weems, Joyce" <> on 01/25/99 01:19:32 PM

To:   rkline
Subject:  RE: microsieve size

But exactly how do you use it? How much do you put in what volume and do
you filter it daily, etc etc etc. Thanks! Joyce

>Sent:    Monday, January 25, 1999 11:04 AM
>To:      Gayle Callis
>Subject:      Re: microsieve size
>The molecular sieve to use for Acetone is type 3A, mesh 8-12.  EM Science
>Catalog # MX1583L/1 for 500 g or /3 for 2kg.
>Gayle Callis <> on 01/22/99 05:52:35 PM
>Subject:  microsieve size
>About to try a microsieve for water removal/acetone.  Any recommendations
>on size?
>Gayle Callis

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