From: Matthew J Dowd (mdowd$##$hsc.vcu.edu)
Date: Thu Jul 01 1999 - 13:29:33 EDT
> I know this is a basic query but any suggestions are appreciated. In
> our lab, we seem to have difficulty in obtaining dry THF on a consistent
> basis. In the past, we have distilled it from KOH, and then from
> Na/benzophenone ketyl. Recently, we added an initial step: distilling
> from P2O5, then from KOH, then finally from Na/benzophenone ketyl (as
> outlined in Perrin, DD & Armarego, WLF Purification of Laboratory
> Chemicals). The sodium we use is blocks, stored in mineral oil, and then
> cut into small pieces (as small as possible). At first, the addition of
> the P2O5 step seemed to improve the drying process. But, after a few
> distillations from the Na flask, that flask seems to be getting very
> cloudy and is taking very long to form the blue ketyl.
>
> I was just wondering if anyone has had similar problems and, if so, as
> determined a solution.
>
> Also, how long should the indicator last in the Na flask? Is it
> necessary to replenish it (because of degradation/breakdown)?
>
> Thanks for your time.
>
> Matt
>
>
_______________________________________________________________________________
Matthew J. Dowd
Department of Medicinal Chemistry
Box 980540
Virginia Commonwealth University
Richmond, VA 23298-0540
Tel: 804-828-6454
Fax: 804-828-7625
Email: mdowd$##$hsc.vcu.edu
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